NOTICE TO MEMBERS

The Secretary begs to inform the members of the Society that

the membership is having a very satisfactory growth since the last

issue of the Transactions. Without question the policy outlined

there, which has since had the sanction of the annual meeting, is

appealing both to the old members and to others interested in

Biology and in the Microscope,—physicians and teachers.

A membership of 400 will enable the officers to publish regu-

larly a Quarterly the size of the last issue (100 to 125 pages).

If each member will secure and recommend at least one new

name, we can have a membership of 400 in a short time. One

busy member has added 7 to the membership in the last month.

Will the members generally not show some of that interest in

the Society that you rightly expect of your Secretary, and extend

to the Society the benefit of your personal acquaintance and influence

with people who might be, or become, interested.

OFFICERS.

Presidents Au Eu ELERTZEER VMN. 2 be ee Sana ye eranah Ube avaliae Kansas City, Mo.

Vice President: M. J. Evrop......... Aa Ue AMIE A aan aah Missoula, Mont.

ISZGRE LATA HIN LT) WN GALL OWA Wis sclera alerebetee pale ena pstalcbotay al atelier ab atelersya1 a Decatur, Ill.

RC OUSUPLE Ile let EVAINIRSE ISON s/c ce iat Nha cual oiailetay evar clststiet heloteustai ele Charleston, Ill.

GUS 70 HON ANUAGNUS MEELAUIM Maines ceaiclelelcie cia sieike sleelatel Meadville, Pa.

ELECTIVE MEMBERS OF THE EXECUTIVE COMMITTEE

eT OL COLMA eine Van aume alu ALA cian ie SMPs ERA IL aaa aly AU oe Lincoln, Neb.

TL! TBS NWO 04 Wot pele aint aU Meir Rig es tir ty Sas ex Om RAGE CMR ae RU Gambier, Ohio

TEL TINGS {Coe eh Je eR RNA I ALR) A oY PD ta LH A AH Buffalo, N. Y.

EX-OFFICIO MEMBERS OF THE EXECUTIVE COMMITTEE

Past Presidents still retaining membership in the Society

ROE VViARD, MoD!) BRIM. S. ofiiroy, Ney. ,

at Indianapolis, Ind., 1878, and at Buffalo, N. Y., 1879.

J. D. Hyatt, of New Rochelle, N. Y.,

at Columbus, Ohio, 1881.

Apert McCatta, Ph.D., of Chicago, Il.

at Chicago, IIl., 1883.

T. J. Burritt, Ph.D., of Urbana, III.

at Chautauqua, N. Y., 1886, and at Buffalo, N. Y., 1904.

Gero. E. Fett, M.D., F.R.M.S., of Buffalo, N. Y.,

at Detroit, Mich., 1890.

MarsHALL D. Ewett, M.D., of Chicago, III,

at Rochester, N. Y., 1892, and at Boston, Mass., 1907.

Simon Henry Gace, B.S., of Ithaca, N. Y.,

at Ithaca, N. Y., 1895 and 1906.

A. CiirForp Mercer, M.D., F.R.M.S., of Syracuse, N. Y.,

at Pittsburg, Pa., 1896.

A. M. Brette, M.D., of Columbus, Ohio,

at New York City, 1900.

C. H. Ercenmann, Ph.D., of Bloomington, Ind.,

at Denver, Colo., 1901.

CuHartes E. Bessey, LL.D., of Lincoln, Neb.,

at Pittsburg, Pa., 1902.

E. A. Birce, LL.D., of Madison, Wis.,

at Winona Lake, Ind., 1903.

Henry B. Warp, A.M., Ph.D., of Lincoln, Neb.,

at Sandusky, Ohio, 1905.

Hersert Ossorn, M.S., of Columbus, Ohio,

; at Minneapolis, Minn. 1910

The Society does not hold itself responsible for the opinions expressed

by members in its published Transactions unless endorsed by a special vote.

TABLE OF CONTENTS

FOR VOLUME XXX, Number 1

The Address of the President. Some Thoughts Concerning the Scope

and Future Work of the American Microscopical Society, by Herbert

Oshorit (eco sk ied ence ct ot ss sae ee Sent eee Lee ee eee 5

Studies on a Phosphorescent Bermudan Annelid, Odontosyllis Enopla

Verrill, by T. W. Galloway and Paul S. Welch, with Plates I to V... 18

The Etiology of Trachoma, by H. C. Solomon, with Plate VI............. 41

The Theory of Nerve Components and the Fore Brain Vesicle of Verte-

brates iby Le Mvaridacrels ssc ccc oe nie ele soley ee ice ee eRe 57

Notes, Reviews, etc. A Plea for Microscopy; Some of the Needs of the

Society; Micrometric Measurements; The Centrosome in Living

Protoplasm; Life Cycle in Ameba; Diatoms as a Food Supply; A

Peculiar Achlya; Transformation of Species of Vaucheria; Sexual

Periodicity in Dictyota; Quinone Fixation of Algae; Growth of

Nerves in Culture Media; Causes of Conjugation in Paramecium;

Bacillus of Typhus; Device for Transferring Specimens; Charts to

Suit the Course; The Build of a Microscope; The Leitz Double Dem-

Onsthatlonass Eyepiece navi ee ek esis im halen Ree Oe eee 67

Necrology.

William Henry Seaman, LL.B. M.D., with Portrait, by S. L.

Asaiby, > ING AR 9. 2k eae en Se ain basse k pterete eae osetia oa 79

NOTICE

The financial statements of the officers did not reach Minne-

apolis in time for audit and approval by the Society in its annual

meeting. The Auditing Committee appointed to receive these reports

has not found it possible to audit them in time for publication in

the January number.

All the minutes of the meeting, therefore, together with the

reports of the Treasurer and Custodian will appear in the April

number.

The names of the newly elected officers appear on the pre-

ceding page.

TRANSACTIONS

American Microscopical Society

(Published in Quarterly Installments)

Vol. XXX JANUARY 1911 No. 1

THE ADDRESS OF THE PRESIDENT

MINNEAPOLIS, MINN., DECEMBER 27-28, 1910

SOME THOUGHTS CONCERNING THE SCOPE AND

FUTURE WORK OF THE AMERICAN

MICROSCOPICAL |SOCIETY

By HERBERT OSBORN

It is no doubt sufficiently evident to the members of the So-

ciety that it is at present in a particularly critical period of its

history. It is equally evident that something decisive should be

done in the near future either to provide for the perpetuation

and growth of the society, or its dissolution in some manner that

shall be consistent with the important and dignified position it has

occupied in the past.

To those who have followed the fortunes of the society from

the beginning, there is doubtless a profound sorrow in any thought

that the organization can have outlived its usefulness; but they

are not alone in such feeling for I believe it strictly true to say

that many of the members who have come into the society in later

years, and who have become at all acquainted with its history

and achievement of the third of a century, cherish a deep regard

for it and a hope that it may continue in its honorable career.

That the society should have outlived the particular sphere

of service for which it was founded is but a consequence of

growth and changed conditions, part of which are largely due to

5 HERBERT OSBORN

the activities and success of the society itself. It does not follow,

however, that the society cannot take on new activities or adapt

itself to new forms of service in the interest of the subjects it

was organized to promote. To do this, however, may involve a

candid recognition of the changed conditions and a willingness to

adapt its work accordingly.

It seems, under the circumstances, not only proper but per-

haps a duty that, as President of the Society, | should open up the

question as it appears to me and at least suggest some lines along

which the thought and discussion of the members may be directed.

In doing so, however, I trust I may not be understood as urging

any particular policy in an official capacity but as presenting cer-

tain facts and conditions as they have been forced upon me in

the time during which I have been a member and officer in the

society.

Of the different factors which have conspired to weaken the

society in recent years, two I think should be considered as of

special importance since they are the two which have a contin-

uous effect. First, the specialization of many branches in which

the microscope is used as an instrument and the consequent diver-

sion of members (and the papers resulting from their work) into

other societies and, second, the great multiplication of technical

societies which has made it increasingly difficult and burdensome

for scientific workers to retain membership and to present the

results of their studies in the different societies in which they might

be interested. The American Microscopical Society is not alone

in being affected by these conditions and in fact has suffered less

than some which might easily be compared with it in scope of

activity and length of life.

The microscope, as we will all admit, is an instrument for

service in many varied lines of research and instruction. During

the years of its development it formed in itself a great field for

investigation and experiment and no one can measure the service

to science at large, or to human industries and human welfare in

general, by the societies which stimulated to the utmost the im-

provement and perfection of the instrument. While this improve-

ment is still in progress we have reached such a degree of per-

fection that the new developments are extremely technical and for

THE ADDRESS OF THE PRESIDENT yf

the most part interest the general microscopist only after becom-

ing available in his work. We are working with a highly per-

fected tool and most of us are much more concerned with the

results of our work than with the instrument with which we work.

In the early days of this society the microscope was a fad

and microscopical clubs flourished in many places. Comparisons

of work and tests of favorite instruments was as great an item

to its votaries as that of airships today for the aviators.

In the same spirit there arose hosts of camera clubs with the

camera as the basis, and these flourished and declined in due time

and now photography is as much a servant of all branches of sci-

ence aS microscopy.

So too, the bicycle had its day of development and exploita-

tion with hosts of clubs and societies the most of which have dis-

appeared with the universal use of the vehicle and the appear-

ance of other attractions for the amateurs. The automobile shows

the same course and doubtless the societies for promotion of aero-

nautics will likewise have their day, serve their purpose and in

time follow the course of mundane things.

It is certainly no discredit to the microscope that its position

has changed from that of a scientific toy or a basis for the excite-

ment of the wonder of the multitude, the gratification of the “Oh

my!” instinct in humanity to that of any every day tool for the

use of the world; that it should have become the necessary basis

for innumerable lines of work and occupy its place in the labora-

tory, the schcol room, the physician’s office, the laboratories of

the experts in geology, chemistry, mining, bacteriology, entomology,

and in fact, almost every branch of study or activity that one can

name.

This general utility is just what its devotees claimed for it

in its period of development, and just what they wished for and

expected from their knowledge of the practical value of the in-

formation to be gained by a proper study of the minute things of

nature that were to be understood only by such enlargement to

vision as was accomplished by the microscope.

The scope of this society, however, was broader than the mere

exploitation of an instrument, in fact has covered the different

8 HERBERT OSBORN

fields of scientific research in which the microscope and microsco-

pical methods have been a factor.

While a large part of its early life may have centered in pop-

ular displays and exhibition of different types of instruments and

in the accomplishment of spectacular feats possible with different

makes, it has also stood for solid progress in microscopical tech-

nique and for results.of scientific value in the special fields of sc1-

ence in which it must be used.

Then if the society has accomplished the purpose for which

it was organized. is there any reason for its continuance? Some

argue that having done so, the best policy is for it to gracefully

admit the logic of events and die and take its burial in the most

dignified manner possible.

But are the objects for which it was organized fully accom-

plished? Is there no more work which it may legitimately and

successfully pursue? Does its membership feel that the time has

come for it to permanently disband and turn its strength and vital

forces into other organizations which just at the present time appear

blessed with greater vitality? These are questions confronting us

and which demand candid and fair consideration not only in justice

to the present organization but for those who in future years might

find in this society the most favorable conditions for their scientific

progress.

Personally I feel that there is advantage in numerous independ-

ent agencies for the encouragement of scientific research, in order

that every earnest, honest, scientific worker may, if possible, find

his opportunity and a medium for his recognition in the world of

science. One reason why a great amount of the scientific product

of the past has come from the universities has been that they have,

throughout their history, represented the greatest freedom of activ-

ity, and that in some one or another of them the ardent seeker for

knowledge has found opportunity and a hearing. So then I would

regret to see any organization which can offer opportunities for

independent action and the encouragement of scientific research

cease its efforts or relinquish its control of its resources.

As a practical means of continuing its activity, there is the

plan of publishing an annual volume, or the papers available in a

quarterly as may be deemed most expedient, which would avoid

THE ADDRESS OF THE PRESIDENT 9

the suspension of a publication now numbering 29 volumes, and

which includes in these volumes a great number of valuable con-

tributions to science.

Whether a special effort should be made to convene the society

in a regular annual session may be open to discussion. Certain it

is that the history of the last ten years has shown the improbability

of securing any such attendance on these meetings as marked the

earlier gatherings. Nor do I believe that much change in this respect

can be expected. The day for spectacular displays in the line of

microscopy is past. We are working as microscopists on problems

in which the tool is subordinated to the subject and while triumphs

of microscopy are numerous and illuminating, they appear in the

light of triumphs of some special field in which the microscope is an

essential and recognized necessity.

But meetings and the reading of papers in public are by no

means an essential function of a society. In these days of rapid

publication the printed page is more potent than the spoken address,

at least for most of scientific contributions, and a well edited journal

with a varied range of articles, such, for instance, as the admirable

number just from the press, can serve a most useful purpose to

science and at the same time serve to keep our membership in touch

and enthused with the opportunities open to all.

There is further the question as to the Spencer-Tolles Fund

which the Society is in duty bound to preserve and administer in

such a manner as to promote the objects for which it was founded

and toward which so many individuals have contributed. Whether

the fund could be disposed of in any creditable manner so as to

relieve the Society of this responsibility is a legal question which I

do not undertake to discuss, but this much is certain, that it was

given with the expectation that it be administered by this Society

and until it is proven that the Society is unequal to the task it is

safe for it to do this to the best of its ability.

With the income now available from this fund it is certainly

possible with the earnest effort of devoted officers to encourage

research along a number of lines appropriate to the sphere of the

Society.

Among the lines of work particularly open for this Society,

it appears to me there are especial opportunities in Parasitology and

10 HERBERT OSBORN

Aquatic Biology. Neither of these subjects has as yet any official

publication in this country, and both are subjects in which there is

great activity and need of encouragement in the way of avenues

of publication.

In the field of Parasitology there has been a marvelous growth

in knowledge of those organisms which are related to disease, and

investigations in this matter will certainly be greatly multiplied in

the years to come. On account of the minuteness of the forms and

their modes of transmission, the problems connected with them are

essentially microscopic and they involve a great deal of special

technique which can be most appropriately developed by means of

this Society and its publications issued in its journal. Even among

the parasitic forms included in the group of insects, there 1s

wide opportunity for investigation, and while much of this matter

might be issued through the Entomological journals, there is much

investigation in this field, especially that which involves particular

microscopic technique, which might very appropriately be consid-

ered as belonging within the sphere of this Association. Certainly

papers in this line would be most welcome to the Society and reach

a very appropriate audience. Perhaps no better emphasis of this

point could be asked than the excellent summary of Prof. Ward

just issued in the Transactions.

For the development of Aquatic Biology which has already

been a considerable feature in the Society, there is no really special

journal in America, and as has been already suggested, the Society

may very properly give itself particularly to this line of work. The

questions for investigation in this direction are of such varied

character and involve a development of so many different phases of

Biology, that they do not in many cases fall strictly within the

limits of any of the common fields of investigation. While the

organisms themselves may be assigned to particular groups of plants

or animals, the relation they bear to each other, the ecologic condi-

tions of their existence, and the particular technique in their inves-

tigation, furnish a very distinct series of problems, and in these

there seems to be a most attractive and important field for the

members of this Society.

Further, there is a large field still open in the matter of develop-

THE ADDRESS OF THE PRESIDENT Ey

ment of technique and particularly of the special methods of work

in certain fields of microscopical investigation which will for a

long period yet offer abundant opportunities for investigation. That

such work belongs essentially to this Society I think no one will

question, and the contributions and discussions in such lines, and

especially of reviews of progress in various fields of Biological

research will give ample room for many workers. A special depart-

ment of Technique will I believe still prove a very popular feature.

Perhaps one particularly useful feature of the Society may be

to bring together workers in the more special branches, and furnish

a common basis for the comparison of methods of work and condi-

tions for progress in their separate fields. This is particularly true

of those lines of investigation which for their progress must depend

upon the bringing together of data from quite varied fields of work.

Altogether it appears that there is still abundant room and a distinct

field of endeavor for the Society.

STUDIES ON A PHOSPHORESCENT BERMUDAN ANNE-

LID, ODONTOSYLLIS ENOPLA VERRILL.

By T. W. GALLOWAY AND PAut S. WELCH

Contributions from the Biological Department, James Millikin

University, No. 7.

I. INTRODUCTION AND NATURAL HISTORY.

During the summer of 1904 the senior author, while working at

the Bermuda Biological Station, had the opportunity to observe

with some care two appearances of a remarkably interesting phos-

phorescent annelid.* The laboratory was at that time located at

Hotel Frascati on the Flatts Inlet to Harrington Sound. The tide

runs freely into and out of the Sound by way of the Inlet. The

worms appear periodically in the waters of this inlet in considerable

numbers and with striking regularity. It was reported to me that

they also occur in the waters of St. George’s Harbor. In all like-

lihood they are to be found at numerous points about the Islands.

Two appearances were observed by me at Frascati, and a third

was reported to me. The first occurred July 3-7, with a maximum

on the 4th; another July 29-31, with a maximum on the 30th. The

latest appearance was reported to me as occurring on August 23;

but details are lacking as to its duration. There is thus an interval

of about 26 days between these maxima.

The full meaning of this interval is not clear. The lunar month

is, however, at once suggested. This would in all probability come

to be established through the tides, either alone and directly, or in

connection with light variations produced by tidal variation. These

agencies might possibly become operative in two ways: (1) in con-

nection with the formation of the sexual cells, and (2) in their

*The indebtedness of the writers'is hereby acknowledged for courtesies extended by

the Bermuda Biological Station (supported by the Bermuda Natural History Society and

Harvard University) and by Professor Edward L. Mark, its Director. The identifica-

tion of the worm was made by Dr. J. Percy Moore of the Academy of Natural Sciences

of Philadelphia.

14 T. W. GALLOWAY AND PAUL S. WELCH

release. How the effects are wrought in this case we are not ina

position to say. The matter should receive more careful local study.

According to the tide tables, the tide was at its lowest for the

day in the Bermudas on July 4 about 6:30 P. M., the moon being in

its last quarter on July 5th. On July 27th was a spring tide; and the

second recorded appearance began July 29th. On July 31 there was

a near-spring tide at its lowest daily phase at 7:30 P. M. While

these two appearances do not show a strict parallelism with the

lunar phases, they do involve a coincidence of low tides and ap-

proaching dark.

If my informant was correct in his dates, the third appearance

would occur at high tide. It is possible that the first appearance of

the season, involving a release of gametes, is stimulated by low

tide or by the coincidence of low tide and approaching dark; that

the time necessary for renewal of reproductive bodies has been

established at approximately the lunar month by a series of circum-

stances, internal and external; and that the release of the sexual

products occurs on the first approach of dark after their maturity

irrespective of the height of the tide at the time.

Parallel instances of periodicity in the formation and release of

sexual bodies are numerous, in which both tide and light appear to

play a part.

In addition to the monthly periodicity, there is a daily period-

icity. On both occasions on which they were carefully observed they

appeared each day, within fifteen minutes of the same time, just as

dusk was becoming pronounced.

The display lasted from twenty to thirty minutes. Only a few

appeared at first, each evening. The numbers gradually increased

to a maximum, when scores might be seen at once. The display

waned somewhat more rapidly than it waxed. An occasional belated

specimen sometimes appeared some minutes afterward.

In a similar way, not so many individuals were seen on the

first evening of each period. On the second or third night they

reached a maximum, and again dwindled in numbers on following

days. :

Of the three appearances, that of early July was the most

numerous, and that of August the least so. This suggests an annual,

STUDIES ON ODONTOSYLLIS ENOPLA VERRILL 15

as well as a daily and monthly maximum; but this needs further

observation.

The males and females differ considerably in size—the females

often being twice as long as the males. The larger female speci-

mens attain a length of 35 mm. Both sexes are distinctly phos-

phorescent :—the female with strong and more continuous glow, and

the male with sharper, intermittent flashes.

In mating, the females, which are clearly swimming at the sur-

face of the water before they begin to be phosphorescent, show

first as a dim glow. Quite suddenly she becomes acutely phos-

phorescent, particularly in the posterior three-fourths of the body,

although all the segments seem to be luminous in some degree. At

this phase she swims rapidly through the water in small, luminous

circles two or more inches in diameter. Around this smaller vivid

circle is a halo of phosphorescence, growing dimmer peripherally.

This halo of phosphorescence is possibly caused by the escaping

eggs, together with whatever body fluids accompany them. At any

rate the phosphorescent effect closely accompanies ovulation, and the

eggs continue mildly phosphorescent for a while. The fact that the

luminosity is known at no other time is further suggestive that it

is produced by the material which escapes from the body cavity.

If the phosphorescent glands are external, as the histology of the

epidermis at least suggests, the discharge of the glands is closely

correlated with ovulation.

If the male does not appear, this illumination ceases after 10 to

20 seconds. In the absence of the male the process may apparently

be repeated as often as four or five times by one female, at intervals

of 10 to 30 seconds. The later intervals are longer than the earlier.

Usually, however, the males are sufficiently abundant to make this

repetition unnecessary; and the unmated females are rare, if they

are out in the open water. One can sometimes locate the drifting

femaie between displays by the persistence of the luminosity of the

eggs; but the male is unable to find her in this way.

The male appears first as a delicate glint of light, possibly as

much as 10 or 15 feet from the luminous female. They do not

swim at the surface, as do the females, but come obliquely up from

the deeper water. They dart directly for the center of the luminous ~

16 T. W. GALLOWAY AND PAUL S. WELCH

circle and they locate the female with remarkable precision, when

she is in the acute stage of phosphorescence. If, however, she ceases

to be actively phosphorescent before he covers the distance, he is

uncertain and apparently ceases swimming, as he certainly ceases

being luminous, until she becomes phosphorescent again. When her

position becomes defined he quickly approaches her, and they rotate

together in somewhat wider circles, scattering eggs and sperm in

the water. The period is somewhat longer on the average than when

the female is rotating alone; but it, too, is of short duration.

So far as could be observed, the phosphorescent display is

not repeated by either individual after mating. Very shortly the

worms cease to be luminous and are lost. Often they give the

appearance of sinking out of sight; however, this appearance 1s

negatived by the fact that I have caught both sexes at once by

timing the current and dipping down stream, as much as six or eight

feet from the point of latest visible phosphorescence. Sometimes as

many as two or three males seem to take part in one mating.

The females caught and examined immediately on becoming

luminous are full of eggs. Those caught after three or four displays,

or after copulation, are largely empty of eggs; yet the different seg-

ments of one worm will differ widely in this particular. Eggs are

often caught among the sete and at any other points where they can

be held.

Specimens in confinement after copulation may be aroused into

mild phosphorescence for at least an hour.

The group of mating adaptations in this Syllid is peculiarly

large and complex; and the elements entering into the precision with

which the eggs and sperm are brought together are quite worth not-

in. Ina number of counts made of eggs captured in connection with

the copulating worms, I found a range of 45-80 per cent of fertilized

eggs in five batches taken at random. Considering the external

fertilization of the eggs this must be considered very high. It is

quite probable that this is a higher result than would be attained if

the eggs and worms had been left in the sea.

The following correlated adaptations are noteworthy:

1. The concentration of the ripening and production of the

ova and sperm into a few days of each month, in the worms of a

STUDIES ON ODONTOSYLLIS ENOPLA VERRILL 17

given locality; and the coincidence of the periodicity of the male

and female.

2. The further concentration of these processes into 30 min-

utes of the twenty-four hours, and at the coming of darkness.

3. The coincidence of the luminosity with the emission of eggs

and, so far as we know, its confinement to this period.

4. The repeated periods of luminosity of the female—serving

as an adequate lure for the male, even though his distance may be

considerable.

5. The sex-dimorphism in the character of the flashes in male

and female, which may serve as recognition marks.

6. The fact that the females swim at the surface of the water

at this time, while the males are beneath the surface until the

former become luminous, enables the males to locate the females with

greater precision. This position of the female may also make the

oxidation more complete, and thus secure the increased luminosity.

7. The eyes of the male are perceptibly larger than those of

the female, in spite of the fact that the females are distinctly larger

than the males.

Hee CLASSIC A DIGN:

The Syllidae, of which Odontosyllis is a genus, are an inter-

esting and widely distributed family of annelids. While nothing is

known of the habits and manner of life of this species of Odonto-

syllis except what is seen in this mating period, there are numerous

striking features of the family recorded. They are mostly free-

swimming forms; but it is believed that they dwell largely amidst

the fixed vegetable and animal growths between the tide-marks, or

at shallow depths, and seek their food there. Some species are

known to be commensal with sponges. Certain species of Autolytus

are reported to be parasitic on nemerteans, and other species of

Polycheta. In such cases the proboscis is said to be incapable of

being retracted.

To the general student the most remarkable facts about the

family relate to the methods of reproduction. As in some of the

naidiform Oligocheta, the non-sexual reproduction by “budding”

is a common occurrence. This budding may be of the nature of

transverse fission, as in the naidiform worms; or it may be lateral,

18 T. W. GALLOWAY AND PAUL S. WELCH

sometimes even with rosettes of buds rising from the side of the

body. In one species of Autolytus the budding may continue from

these primary buds in such a way as to produce a complex, much

branched stock very similar to plant growth. As will be recog-

nized, this is an uncommon occurrence among animals as highly

differentiated as the Syllids. In Autolytus and some other genera,

possibly in many of the genera, a non-sexual nurse-stock gives off

numerous sexual buds or zooids, which ultimately escape and mate

as free-swimming worms. The embryos develop into the nurse-

stock and thus a somewhat complicated alternation of generation

comes about.

Malaquin (1893) diagnoses the family Syllidae as follows:

“Cephalic segments provided with 5 appendages: Namely, two palpi;

two lateral and one median antennz; and two pairs of eyes. The peristomial

(post-cephalic) segment usually has two pairs of tentacle-like cirri,—some-

times only one pair. The succeeding segments have feet consisting only of

the setigerous lobe of the ventral division, together with a dorsal and a ven-

tral cirrus. The dorsal division of the foot often develops at the time of

sexual maturity. The proboscis is protrusible, and consists of two regions:

(1) the anterior (pharynx) chitinous and with one or more teeth; (2) the

muscular gizzard, which is a secondary development of the pharynx of the

larva. Reproduction is distinguished by the appearance of secondary sexual

characteristics (such as enlargement of the eyes, elongation of the antennae,

development of swimming bristles and of genital glands, and often of phos-

phorescent organs). The ordinary individual may thus itself become sexual

by these changes (epigamy); or it may give rise to new and special buds

which separate and assume the sexual characteristics (schizogamy).”

The Syllidae are divided into the following sub-families :

Fused ieee Soy cect tols ayant Exogonea.

: Palps present... cabaret ixt: DASExOmy;-1.t- steele Eusyllidae.

Syllidae. Separates cet sik he ore Seis eee nee

Pall psrawanitinion hnrecictoracrcertem bocca eeetat iar tevsie ania eee eee Autolytea.

Malaquin defines the Eusyllidea, to which Odontosyllis belongs,

thus:

“Syllidae with ventral cirrus (McIntosh says that these may be absent;

they are wholly wanting in both sexes of the worm under consideration) ;

palpi fused at the base only. Tentacular cirri filiform and cylindrical, with

surface constrictions. Reproduction epigamous (direct).”

Odontosyllis was established as a genus by Claparede (1863)

and is described as follows:

“Palpi short or moderately elongated; more or less separate or fused at

STUDIES ON ODONTOSYLLIS ENOPLA VERRILL 19

the base. Tentacles (3) and the dorsal cirri filamentous, short—becoming

longer in sexually mature zooids. Nuchal organ has a central pit. Tentacular

cirri in two pairs. Ventral cirrus present [not in the sexual zooids of O.

enopla]. Proboscis with a series of horny papilla, the points curved back-

ward. Ventricle (stomach) short and devoid of T-shaped ceca. Bristles

with the terminal piece simple or bifid.”

Verrill (1900) has described Odontosyllis enopla as follows:

“A large species with a dark brown, wide, short esophagus, armed with

a ventral row of six stout, recurved, hook-like teeth anteriorly, besides the

median dorsal tooth.

Head large, broader than long, broadly rounded in front and on the

sides; posteriorly with two rounded lobes, separated by small median emargi-

nation. Eyes black, unequal, the anterior ones much larger, reniform; those

of each side are so close together that they seem to be almost in contact.

Palpi shorter than the head, rather wide, thin, often wrinkled or folded

in contraction, and commonly curved downward.

Tentacle tapered, rather slender, not annulated, its length about 1% times

that of the head. Antennae similar, about % as long. Tentacular cirri sim-

ilar to the tentacle, the upper one rather larger and longer; the lower ones

shorter ; first dorsal cirrus decidedly longer and larger than the upper tentac-

ular cirrus. Succeeding ones mostly shorter, unequal, alternately shorter and

longer, tapered distally; the longer ones are equal to the breadth of the body,

the shorter ones about % as long; those on setigerous segments 3, 4, 6, 9 are

longer than the others.

The sete are all similar, numerous, slender, short, projecting but little

beyond the parapodia, with short, rather wide blades, ratio as 1:2'%4-3; their

tips are strongly incurved and acute, with a small denticle a little distant from

the end. [Fig. 16, V.] Two spiniform yellow acicula usually occur in each

fascicle.

The esophagus is short and occupies about 4 segments; its margin is

incurved and strongly emarginate dorsally. It bears a group of 6 [see Figs.

18, 19, 23] nearly equal, parallel, recurved hooks or teeth, which are large and

strong. The conical dorsal tooth is near the margin.

The stomach is large and occupies 8 segments; it is wide, elliptical, and

about twice as long as the esophagus. Its surface is covered with angular or

alveolar markings, often hexagonal, so as to have a honeycomb-like appear-

ance, but not arranged in definite rows.

Color, in formalin, is nearly white, except when containing eggs.

Length, 25mm; diameter, about 1.5mm.

One of the largest specimens has all the segments back of the gastric

region filled with eggs.”

III. GENERAL AND EXTERNAL MORPHOLOGY.

As in the other_nereidiform worms, the body is elongated and

very mobile. The length varies in the observed specimens from 19

20 fT. W. GALLOWAY ANI) PAUL S. WELCH

to 35 mm. The males are distinctly smaller than the females. Just

back of the head the body is almost cylindrical. The dorsi-ventral

diameter grows continuously shorter from before backward, while

the transverse diameter lengthens for about 40 segments, after which

it too gradually diminishes.

The segments vary in number from about 110 to 130, in the

twelve or fifteen specimens examined. They may be grouped in

the following regions: (1) a head with 3 to 6 supecialized segments

including the first setigerous segment; (2) an anterior body region

of 23 or 24 segments, in which there is a gradual increase in the

right-left diameter, and upon which the dorsal portion of the para-

podium (notopodium) bears no setz, although the ventral process

(neuropodium) does; (3) a mid-region, comprising some 30 to 32

segments, and similar to the last segments of the preceding region

but for the fact that each notopodium bears a cluster of long,

swimming sete in addition to the neuropodial sete; (4) a posterior

region, similar to the second region in that the notopodial sete are

lacking, which includes all the rest of the worm, except—(5) the

specialized anal segment which bears beside the anus, a pair of

elongated cirri. The variation in the number of segments in the

worms is due to differences in the fourth region enumerated above.

The length of the other regions is subject to very little variation.

The Head.

As is usual in the polychetes the head is well differentiated, and

the problem of its segmentation is not an easy one. There is the

usual pre-oral portion known as the prostomium; the mouth itself;

and a region surrounding the mouth and just back of it, the peri-

stomium. See Figs. 2, 5, 12, 13. This specialized head includes

the first setigerous segment and everything in front of it. If the

prostomium, as is held by Malaquin, consists of one segment only,

the head of Odontosyllis contains four segments. If, as Pruvot

thinks, the prostomial lobe represents a modification of three seg-

ments, there are six segments in the head.

If we regard the prostomium and its outgrowths as fully hom-

ologous with the structures in other regions of the body it would

seem that Pruvot’s contention is the sounder of the two. For the

dorsal prostomial lobe bears three types of paired sensory struc-

STUDIES ON ODONTOSYLLIS ENOPLA VERRILL 21

tures: foremost of all, two ciliated palps; back of these and sepa-

rated from them by a groove, the pair of lobes bearing the eyes, of

which there are two on each side of the head; and, lying between

these lobes, the three tentacles, one medium and two lateral (Fig.

12). It is not easy to see how this region can be regarded as seg-

mented at all and consider it of less than three segments; but in

the light of the embryonic development of this and similar worms

it is questionable whether it is sound to try to homologize the div-

isions of this prostomial organ or even the whole organ with the

segments of the body. In the larva of Odontosyllis, as in other

Syllids, segmentation is distinctly a secondary state, superimposed

on the posterior part only of trochosphere. The anterior enlarged

portion seems not to share in this embryonic segmentation. In our

opinion the prostomium rather represents a modification of this

unsegmented anterior outgrowth of the trochosphere. It is not even

morphologically a whole segment; but is rather an outgrowth and

specialization of a portion of the first embryonic segment.

The peristome, on the other hand, is clearly of three segments,

each bearing a pair of lateral cirri becoming progressively more

dorsal. Only the third of these segments (posterior) appears, how-

ever, as a complete ring of the body. The dorsal part of this seg-

ment may protrude in the form of a flap covering the base of the

lobes bearing the eyes (Figs. 1, 13, F.). In life this is quite dis-

tensible. A ventral projection of this same segment froms the lower

lip (Fig. 5). The first and second segments show only as partial

rings extending from the side of the mouth to the over-arching

prostomium.

The Eyes.

The four eyes are arranged in pairs, two eyes on either side of

the median line (Figs. 1, 12, 13, Ey.) They are mounted on pro-

truding lobes which are capable of a certain amount of motion. The

anterior eyes are somewhat larger than the posterior ones, though

not markedly so. The eyes of the males are distinctly larger than

those of the females. In measurements of the eyes of two males

and three females, after making allowance for differences in planes

of sectioning, there is a difference of 10-30 per cent in favor of the

males. The opening into the pigment cup (pupil) of the anterior

22 T. W. GALLOWAY AND PAUL S. WELCH

eyes in the normal position is directed forward and outward; that

of the posterior ones, dorsally (Fig. 1, E.)

The cuticle which covers the front of the eye is a continuation

of that which covers the exterior of the body. The lens is a spherical

body lying in the cavity formed by the pigment cup (Fig. 7 Le.) It

appears to be connected with the cuticle through the opening in the

pigment cup, by a slender stalk or pedicel. After fixation the lens

shows as a somewhat fibrous substance surrounding at various

places roundish bodies which stain with greater intensity. It gives

the appearance of a semi-fluid substance, that has been coagulated

by reagents, rather than of cells. It stains readily and is rendered

somewhat brittle by the usual methods of fixation and treatment.

The remaining regions of the eye—rods, pigment layer, retinal

cells, and optic nerve, which form the wall of the cup of the eye are

not really four distinct regions, but are continuations and differenti-

ations of one layer of cellular elements. The wall of the cup is

formed of numerous long and narrow elements (ommatidia) all

essentially alike, with the long axes in a radial position. Each om-

matidium is a highly differentiated cell (Fig. 8). The outer end of

each cell narrows into a nerve fibre which enters into the optic nerve.

Near this end the cell has its greatest dimensions and contains a

large,‘ conspicuous nucleus. The middle part of each of these

cells is covered with a dense pigment (Fig. 8, Pg.) The united

effect of these pigmented regions lying side by side is to produce the

pigment layer which is very conspicuous and appears continuous.

The inner part of the cell projects towards the lens as a clear hyaline

rod. These rods form the peripheral part of the refracting mass,

but are morphologically a part of the retina. The pigmented cup is

continuous, except at the dorsal region where it is interrupted by a

small circular aperture, the pupil, through which the pedicel of the

lens passes. ;

Parapodia.

In the regions of the body, described above as anterior (2) and

posterior (4) the dorsal ramus of the parapodium (notopodium) is

specially reduced and rudimentary. It is bilobed, consisting of two

short processes or tubercles. The dorsal of these is larger and bears

a dorsal cirrus (Fig. 21 Ci.) These cirri are chiefly outgrowths of

STUDIES ON ODONTOSYLLIS ENOPLA VERRILL 23

the epidermal layer of cells; but fibres from the circular layer of

muscles pass to their bases. The ventral lobe of the notopodium is

a smaller, pointed process, bearing no external structures in this

region. In the mid-region of the body this lobe bears a conspicuous

bunch of about 40 long capiliform, non-branching sete, arranged

in two parallel rows in the sac (Fig. 10, S’”), and is supported by an

aciculum.

The ventral ramous (neuropodium) is well developed through-

out. It consists of the usual larger dorsal and smaller ventral lobes.

The dorsal lobe has at its outer extremity a cleft or sac in which the

setee are imbedded. These sete differ from the dorsal ones in being

jointed, having a long stalk with a small incurved appendage (Fig.

16, V.). This lobe is also supported by internal acicula which reach

the surface (Fig. 21, 4). The setz of both kinds sit on the basement

membrane of the external epithelium and clearly arise from the

modified epithelial cells lining the sac (Fig. 9, C). The ventral lobe

of the neuropodium is small and does not produce the ventral cirrus

usually described as characterizing the Syllide.

IV. INTERNAL ANATOMY AND HISTOLOGY.

The Body-wall.

The body-wall is composed of the four usual regions; viz., (1)

the cuticle, (2) the epidermis, (3) the muscular system and (4) the

parietal peritoneum. '

The secreted cuticle is of about the same thickness in all regions,

except in a location just anterior to the peristomial flap where it is

much increased in thickness (Fig. 6, £7). It shows the following

perforations: (1) the pores of the epidermal glands; (2) the points

of emergence of the setz from the body-wall; and (3) the external

openings of the nephridia at the ventral basal region of each para-

podium.

The cuticle takes any of the general stains, showing up pecu-

liarly well when treated with haematoxylin. It possesses a character-

istic luster which is apparent in all preparations, irrespective of the

kind of treatment. Under the highest powers the homogeneous

appearance gives way to a suggestion of very fine intersecting lines.

The striations perpendicular to the surface are more apparent.

24) LW: GALLOWAY AND PAULTS?) WELECE:

The epidermis is a conspicuous layer of cells in most parts of

the body and is easily traceable over the exterior of the body and

into the anal and oral openings. The epidermis is composed of

three kinds of cells: viz., (1) the ordinary undifferentiated epithelial

cells which compose the greater part of the epidermis; (2) the large

regular gland cells; and (3) the “twisted” gland cells.

In all parts of the epidermis, with a few exceptions to be noted,

the cells of the first class are of the usual columnar type, with con-

spicuous nuclei near the bases. The basement membrane is very defi-

nite in all regions, staining readily with haematoxylin. In certain

quite definite regions these cells vary from the common shape. They

become much more elongated near the base of the parapodium on

both dorsal and ventra! sides. The greatest thickening takes place,

however, in the region just in front of the dorsal flap, that extends

forward from the last peristomial segment, and just at the base of

the brain. At this point the epidermal cells are tremendously elon-

gated—the length in the longest being something like fifteen times

the short dimension, and 6 or 8 times as long as is usually the case

(Fig. 6, E’). This patch of cells has all the appearance of a sensory

epithelium. There are several such patches, less striking, about

the various flaps and folds of the head.

The regular glands are rather numerous, and are found in all

regions of the skin. They seem to be a little more numerous on the

sides of the segments above the bases of the parapodia, and on the

ventral surface to the right and left of the median groove. These

cells have a characteristic shape resembling a truncated cone, the

larger diameter being distal. The cell-wall, nucleus, and cytoplasm

are quite distinct, and the latter has a very characteristic reticulated

structure which is shown in Fig. 15.

The third type of epidermal cells—the “twisted” gland cells—

occur in most parts of the epidermis, and are rather numerous.

They occur in the ordinary regions of the body singly or in small

groups separated by one or more epithelial cells; but they are often

in clusters of 4 or 5 or more on the tentacles and cirri. In general

they are more numerous on the exposed parts of the body, and

much less so in the depressions, though they are abundant at the

lips of such grooves. They are somewhat flask-shaped, usually with

STUDIES ON ODONTOSYLLIS ENOPLA VERRILL 25

irregular surface depressions that give the appearance of a spiral

twist (Fig. 22). They vary considerably in size. Each cell has a

distinct neck, and opens to the exterior through a pore in the cuticle.

The reticulum is conspicuous throughout the cell. Usually these

cells stain densely, especially at the wall. The internal reticulations

are very much less stained. Often the glands show only a slight,

ghostly staining, suggesting a difference of physiological state. The

distribution, and apparently empty condition of many of the glands

suggest that they may be the phosphorescent organs; though of

this the authors have no final proof. In the dorsal region of a male

specimen these glands show a somewhat different structure, as

appears in Fig. 22a., Sg. Here the structure is of a much divided

tubular sort. Their distribution and general relations, however,

mark them as identical with the twisted cells.

The muscles of the body-wall present no significant departure

from the condition described for other nereidiform worms. The

outer circular layers give rise to acicular muscle fibers and to fan-

shaped oblique fibres concerned in the motions of the parapodia.

The longitudinal muscles are massed in four heavy bands—two

dorsal and two ventral. They too give off tracts of fibres to the

parapodia. The general relations of the muscles are very well shown

in Figs. 20, 21. The muscles are unstriate.

The Alimentary Canal.

The alimentary canal is a nearly straight tube running the

length of the body from the mouth to the anus. It is in no wise

degenerate, as in some of the Syllids ; but is functional throughout its

course. Five regions may be distinguished, the last four of which

are sharply differentiated from each other: (1) buccal cavity; (2)

pharynx; (3) esophagus; (4) gizzard; (5) intestine.

A number of features, both embryonic and histological, seem

to suggest the point of union of gizzard and intestine as the begin-

ning of the mesenteron. There is a cuticular lining with very pro-

nounced developments as far as the anterior end of the gizzard, and

in less degree throughout its extent. It will be seen that the chief

differentiations of the tract are in the stomodaeum and that the

mesenteron is quite uniform in size and structure.

26 T. W. GALLOWAY AND PAUL S. WELCH

Mouth and Pharynx.

The first two regions, the buccal cavity and the pharynx, con-

stitute an introvert. When withdrawn the buccal cavity occupies

the peristomium, and the pharynx extends from the first setigerous

segment to the seventh. When fully everted the buccal region is

turned wrong side out, and the terminal opening is directly into the

muscular pharynx, which is pulled forward its full length so that

its posterior end is in the first or second setigerous segment. Com-

pare Figs. 2 and 3.

The oral opening, when the introvert is withdrawn, presents

a lobed margin of which the first setigerous segment furnishes the

posterior ventral portion—a kind of lower lip (Fig. 5). The first

and second peristomial segments form the remainder of the boun-

dary to the mouth. The ventral floor of the buccal cavity is glan-

dular (Fig. 2; 14, g.) while the sides are merely transitional from

the outside to the pharynx. There is also a deep glandular fold

from the dorsal wall of the cavity at the anterior margin of the

pharynx (Figs. I, 2, O).

The anterior part of the pharynx is very thick and muscular,

but the posterior one-third, or thereabouts, is thin and pliable. It

is this latter region that allows the adjustment of the phaynx to the

body space when it is withdrawn into the body. This thin zone is

thrown into a backward directed fold into the coelom, dorsal to the

anterior end of the esophagus (Figs. 2, 3, Ph’.) The anterior end of

the esophagus comes to lie within the lumen of the posterior part of

the pharynx. The wall of the pharynx is composed of (1) the

internal cuticle, (2) the epithelial lining which secretes the cuticle,

(3) a thick muscular coat, and (4) the peritoneum.

The cuticle is continuous with that of the skin and similar to it

in structure, but presents modifications in certain regions. It is

thickened into minute conical denticles over a large portion of the

pharyngeal surface (Figs. 2; 14, dt.). In the dorsal part the dent-

icles begin with the mouth and extend about one-third of the length

of the pharynx. In the ventral floor they begin at the posterior edge

of the glandular region (Fig. 14) and cover perhaps two-thirds of

the floor back of that point. The glands and the denticles do not

occur together.

STUDIES ON ODONTOSYLLIS ENOPLA VERRILL 27

The epithelial layer of the pharynx is thrown into a series of

longitudinal folds, somewhat irregular at first, but becoming more

definite posteriorly. One of these in the dorsal part of the pharynx

has almost the definiteness of form of the typhlosole of the intes-

tine of the earthworm (Fig. 18). The epidermal cells of the pos-

terior portion of the thick muscular region of the pharynx are con-

spicuously glandular. In the thin region, that forms the flexure in

introversion, the cells revert more nearly to the ordinary type of

epithelium.

The muscular layer is the most conspicuous one in the wall of

the pharynx. It consists of a complex of circular, longitudinal, and

radial or oblique fibres. In a longitudinal section of the organ the

circular fibres show themselves to be arranged on both sides of

sheets, which radiate from the lumen outward not at right angles

to the lumen, but in positions depending on the degree of inversion.

The circular fibres appear to dominate in this organ, but it is much

less easy to distinguish the various layers here than in any other part

of the body. Indeed it is easy to see that the layers are not as

independent as elsewhere, and intermix to a greater degree.

The Esophagus.

The esophagus when withdrawn occupies segments 8 to II.

At its anterior margin occurs a ring of cuticular teeth which give

the name to the genus. In the ventral floor there is a row of six of

these,” closely appressed, uniform in size, conical in form, and

curved slightly backward. On the lateral walls near the dorsal part,

and arching over so as to engage the ventral teeth, is a somewhat

larger recurved tooth on either side of the lumen. In introversion

the dorsal ridge of the pharynx is pressed in between these lateral

teeth (see Fig. 18, Df.). It is very difficult to get satisfactory

sections in the region of the teeth.

From within outward the layers in the wall of the esophagus

are: The very much thickened cuticle, comprising about one-third

the thickness of the whole wall; the columnar epithelium; the layer

of circular muscles about the thickness of the epithelium; the longi-

tudinal muscles, two-fifths the total thickness of the wall; and the

thin peritoneum.

The cuticular layer is thicker in the esophagus than at any other

28 T. W. GALLOWAY AND PAUL S. WELCH

part of the body. It stains densely except at the very outer margin

and shows a clear striate structure, the striations running perpen-

dicular to the surface. While the teeth are to be looked upon as

special thickenings of the cuticle, there is a sharp demarcation

between this layer and them (Fig. 23.)

The arrangement and character of the muscles in the region of

the esophagus shows that they are not so much concerned with the

mere action of the esophagus itself as with the larger problem of

introversion and eversion, and of the manipulation of the teeth at

the anterior end of the esophagus. It is not the purpose of this

paper to trace out the course and value of the various muscular

tracts; but an examination of the various figures will suggest the

role of some of the muscles massed about the anterior end of the

esophagus. They bring the latter organ into proper relation to the

processes being initiated by the action of the pharynx, as well as

furnish a point of attachment for some of the elements engaged in

retraction and protrusion. The thickened cuticle of the esophagus

is undoubtedly for this purpose, and for the added purpose of keep-

ing the esophagus open and functional during the various vigorous

changes of form and position of the introvert.

The Gizzard.

The gizzard or stomach is a highly developed structure imme-

diately following the esophagus and sharply demarcated fromat. It

extends normally from about the 12th setigerous segment to the 21st.

It practically fills the body cavity in these segments. It is of uniform

size except where it tapers off rather abruptly to join the esopha-

gus and the intestine. It is elliptical in cross-section; and the lumen

is in the form of a long narrow slit, the sides of which are nearly

parallel. This slit-like lumen divides the organ into symmetrical

halves, whose walls are very thick except in the part opposite the

edges of the lumen. Here it is not more than 1-5 the usual thick-

ness. Apparently the morphological position of the slit is dorsi-ven-

tral; but the whole organ may be rotated until it has a right left

position. From a surface view, or in excentric longitudinal (tan-

gential) section, the whole wall of the organ is seen to be crossed

by a series of fine parallel lines running transverse to the organ.

The band-like spaces between these lines are divided into numerous

STUDIES ON ODONTOSYLLIS ENOPLA VERRILI 2Y

angular areas of nearly uniform shape and size. The whole pre-

sents a remarkably regular and interesting pattern (Fig. 25). Has-

well (1886) has shown in his study of various species of Syllids that

the wall of the gizzard is a highly complex muscular organ; and is

not, as has long been supposed, a glandular one, at all. These studies

confirm his conclusion in all essential particulars.

In detail, the wall of the gizzard, from within outward, shows

the following regions: (1) the epithelium with its very thin secretion

of cuticula; (2) a very much reduced muscular layer (Fig. 24, m1.)

which contains internally one thickness of circular fibres and just

without this a similar single thickness of longitudinal fibres; (3)

a thick zone made up of muscular elements which show chiefly as

radiating columns in a transverse section or in longitudinal sections

radial to the organ (Figs. 21; 2, V; 24, Col.); (4) a thin layer of

elements (Fig. 24, mo.) which certainly contains circular muscular

fibres, and according to Haswell contains longitudinal fibres also;

(5) the thin peritoneal layer.

None of these layers call for special comment with the excep-

tion of the thick muscular layer which furnishes the main body of

the wall of the gizzard.

A view when the gizzard is cut longitudinally, in such a way as

to display the radial elements uncut, would be illustrated by Fig. 2,

V, at the left-hand side of the figure. Such a view shows three chief

topographic features: (1) a series of fibrous columns passing from

the thin inner muscular sheet to the outer; and (2) lying between

these, open spaces somewhat shorter than the columns and tapering

toward both ends; and (3) in the outer portion of these open spaces,

tapering objects, thicker at the outer ends, which extend from the

outer wall about one-half the way to the lumen.

Study of these objects in other sections (see Figs. 2; 24) shows

the radiating columns to be muscle fibres extending the whole thick-

ness of the wall of the gizzard. They appear as columns in the

transverse section of the gizzard also (Fig. 21, 3) but do not have

such well-developed spaces between them. The tapering objects

extending inward between the columns present a granular appear-

ance and are in fact annular muscle fibres cut cross-wise. They

form the transverse lines that show in a tangential section, such as is

30 T. W. GALLOWAY AND PAUL S. WELCH

seen in Fig. 25,Cb. They are in reality thin, wedge-like bands of

muscle fibres that encircle the gizzard and separate the radial col-

umns into successive circular zones, also shown in Fig. 26, Cb. Only

the outer halves of the columns are thus divided, since the circular

bands extend only part way to the lumen. In the cross-section of

the gizzard these circular bands present their fibres in longitudinal

view. They show dimly (Fig. 21, 2) in such sections outside the

wavy line which appears midway the columns (Figs. 21, 24). These

circular fibres are of the usual unstriate type and coalesce with the

circular sheet of fibres of the inner muscular layer at the two edges

of the lumen of the gizzard (Fig. 21, Ra.), and only there. The

wavy line seen in Fig. 24 about midway on the columns seems to be

the mark of the union of the inner thin edge of the circular band of

fibres with the adjacent radial columns.

The histology of the radial columns has been worked out in

much detail by Haswell for several Syllids. The differences between

the conditions in O. enopla and those described by him are of

minor moment, The individual fibrils run the length of the columns

and are undoubtedly made up of alternate light and dark bands,

such as are seen in typical cross-striate muscles. Haswell remarks

that the striations found in these fibres are more strongly marked

than in any crustacean or insect he had examined.

Considered as a whole, each one of these radiating columns of

cross-striate muscle fibrils is made up longitudinally of two sym-

metrical halves hollowed out on their inner faces in such a way as

almost to surround a cavity. This cavity is small and closely sur-

rounded near the inner end of the column, as seen in cross-section

(Fig. 27, f); but in cross-sections further from the lumen, the

space between the two halves becomes larger, and is less com-

pletely surrounded by the muscle fibres. In the outer half of

its course the halves of a given column fall on different sides

of one of the circular bands of muscles referred to above. See

Fig. 26, which represents a cross section of a group of the col-

umns about two-thirds of the way toward the outer surface,

and shows the circular muscles separating the triangular halves of

the columns and thus throwing them into a band back to back with

the nearby halves of the next row of columns. Figure 25 shows

STUDIES ON ODONTOSYLLIS ENOPLA VERRILL 31

the relation of the parts just as close to the outer end of the columns

as a section can be made. In this figure the outer ends of the half-

columns included between two of the bands of circular fibres are

shown almost to run together into a continuous zig-zag sheet. At

this level the space between the circular band of unstriate fibres

(Fig. 25, Cb.) and the adjacent zone of the radial columns (Fig. 25,

col.) is occupied by a mass of granular nucleated protoplasm (Fig.

25, 2). This protoplasm extends only a short distance down the

columns, as appears in Fig. 28, n., which shows a section perpen-

dicular to that in Fig. 25.

In brief summary, then, the gizzard is a complex muscular

organ with an outer and inner sheet of unstriate fibres; a parallel

series of thin bands of annular unstriate muscles, whose outermost

fibres are in close relation to the external muscular layer, and extends

inward as a band from the outer muscular sheet only about one-

half the thickness of the whole wall, except that it reaches entirely

to the inner muscular sheet at the angles of the lumen where the

wall is thinnest and there gives off fibres which unite with it; and a

series of radial columns of striate muscle fibres, each column of

which is made of two trough-like halves whose concave sides are

apposed in such a way as to make a conical cavity with its largest

diameter at the outer end.

From the point of view of histogenesis the most interesting

things about the gizzard are this mixture of striate and unstriate fi-

bres in the single organ, and the evidence that the central cavity of the

radial columns presents at the outer end a remnant of the granular

protoplasm from which the muscular fibrils were differentiated.

Each of these hollow columns is a simple muscular organ, in which

the contractile elements are the product of the single multinucleate

mass of protoplasm occupying its core and it is differentiated pro-

gressively toward the periphery, as is suggested by the last position

of the nucleated protoplasm (Fig’ 28 n.). The embryonic charac-

ter of the mature fibres, and the simplicity of the relation of the

fibres in the organ mark the organism as one that would well repay

study upon the ontogenetic differentiation of the muscles of the

gizzard.

32 T. W. GALLOWAY AND PAUL S.. WELCH

The Intestine.

The intestine is a straight tube passing with nearly uniform

character, and with gradually diminishing size, to the anal opening.

It has the usual constrictions between the segments, with saccula-

tions almost amounting to diverticula within the segments. The

epithelial lining has the usual variety of columnar cells. Those in

the posterior part of the tract are heavily ciliated. Both circular

and longitudinal fibres may be found, but they do not form a definite

or continuous sheet of tissue. Fig. 20 illustrates a cross section of

the body, in the intestinal region, which includes a dissepiment.

The intestine is sharply constricted ; the layer of longitudinal muscle

fibres appears clearly just outside the entoderm; and a thick zone

of circular fibres outside this shows a clear anastomosis with the

circular fibres of the body wall in both dorsal and ventral regions.

The distribution of oblique muscle fibres in the dissepiment is also

shown—the origin being in the ventral region on either side the nerve

cord and passing out fan-wise to the muscular layers of the dorso-

lateral walls. At least some of these fibres run into the circular

muscular sheet in being inserted.

The only noteworthy differentiations in its length are the shal-

low proctodeum, and the valvular enlargement of the intestine at its

junction with the gizzard (Fig. 4, v.). At the beginning of the intes-

tine there is a special annular or sphincter group of muscle fibres

Ghigo ,S))).

The Circulatory System.

The blood vessels agree with those described as characterizing

the Syllids generally, and call for little special discussion. The

dorsal vessel is small and thick-walled as compared with the ventral.

The dorsal vessel is imbedded 1n the wall of the intestine in an inter-

esting way thru a part of its course—the peritoneal membrane in-

closing both in one sheath (Figs. 17; 29). Segmental vessels arise

from both the dorsal and ventral longitudinal vessels and run out-

ward on the anterior face of each dissepiment.

The Excretory System.

The nephridia are quite large organs in this worm in comparison

with the size of the body. This is due in the female to the liberal

STUDIES ON ODONTOSYLLIS ENOPLA VERRILL 33

glandular portion. The nephridia apparently occur in all the setig-

erous segments of the body beginning with the very first—which

is also the last segment of the peristomium.

In the male the tubular ciliated portion of the nephridium is

much larger than in the female, and the glandular part appears less

massive (Fig. 11, V., G.). In the sections of a female, whose cavity

was filled with eggs in such a way as to indicate that ovulation had

not occurred. the tubular part of the nephridia was so compressed

and displaced as to preclude the possibility that they could be used

for the discharge of eggs, at least at the beginning of ovulation. In

the male on the contrary there is abundant evidence that these organs

are in an hypertrophied condition, and probably they function as

vasa deferentia. They have large lumens, and protrude well into the

middle of the body.

Genital Products.

As in other polychetes the eggs and sperm are produced by pro-

liferation from the coelomic peritoneum. They are found in all the

full-sized segments of the body, beginning about the 19th or 20th

setigerous segment. Ripe eggs were found in sections two or three

segments anterior to the union of gizzard and intestine. Fig. 30

shows a cross-section of a female which has not deposited any of

her eggs. In this case the eggs are so numerous that the segment

is stretched until the body wall is very thin. The eggs occupy every

available cavity. As has been indicated it appears to the writers

that the ova could not use the nephridia in this case, but must escape

by rupture of the body wall.

34 T. W. GALLOWAY AND PAUL S. WELCH

BIBLIOGRAPHY

AwnpreEws, A. E.

1892. The eyes of Polychaetous Annelids. Journal of Morphology,

7 :169.

BenHaM, W. B.

1896. Polychaete Worms. Cambridge Nat. Hist. Vol. 2, Chs. 9-13.

CLAPAREDE, A. R. E.

1863. Beobachtungen tiber Anatomie und Entwicklungsgeschichte wir-

belloser Theire, pp. 38-48.

Euters, E.

1864. Die Borstenwiirmer. Erste Abt. pp. 203-232.

GaLLoway, T. W.

1908. A Case of Phosphorescence as a Mating Adaptation. Sch. Sci.

and Math. May, 1908.

HaswEL., Wm. A.

1886. On the Structure of the So-called Glandular Ventricle (Driisen-

magen) of Syllis. Quart. Journ. Micr. Sci. 26:471.

1889. A Comparative Study of Striate Muscles. Quart. Journ. Micr.

Sci 20%3i-

LANGERHANS, P.

1879. Die Wurmfauna von Madeira. Zeitschrift fiir wiss. Zoologie. Bd.

32 2554.

MaLaguin, ALPHONSE.

1893. Recherches sur les Syllidiens. Lille.

McIntosH, Ws. C.

1873. A Monograph of British Annelids. Ray Society. Three Vols.

Moore, J. Percy.

1909. Polychaeteous Annelids dredged off the Coast of Southern Cali-

fornia. Proc. Phila. Acad. Nat. Sci. 61 :321-351.

St. Josepu, A. De.

1886. Les Annélides Polychétes des Cotes de France. Ann. d. Sci. Natur.

Zool. Ser. 9:vol. 3; pp. 145-260.

VERRILL, A. E.

1900. Additions to the Turbellaria, Nemertina, and Annelida of the Ber-

mudas. Trans. Conn. Acad. Sci. 10:pt. 2:627-8.

SEY

TNL

\TE

Fig. 1.

Bigs. 2.

Big: 3:

Fig. 4.

STUDIES ON ODONTOSYLLIS ENOPLA VERRILL 35

EXPLANATION OF PLATES

Plate I

A para-sagittal section of the dorsal part_of the head. Diagram-

matic. E, the pupils of the eyes (see also Fig. 7); F, flap of peris-

tomium (see also Fig. 6) ; O, a glandular fold at the dorsal anterior

edge of the pharynx (see also Fig. 2); P, palp; Ph, pharynx.

A sagittal section of the head and anterior segments, with the

introvert withdrawn. 1, the last peristomial (first setigerous) seg-

ment; az, an annular organ in the cardiac opening of the gizzard,

consisting of modified epithelium and circular muscle fibres; Br.

brain; Cu, cuticula of the esophagus (E); F, a flap projecting for-

ward from the 3rd peristomial segment (see also Figs. 1 and 6); G,

gizzard, in which the dorsal (D) and ventral (V) walls are cut in

different relation to the elements composing the wall; M. mouth; O,

a thin-walled glandular pocket at the anterior, dorsal edge of the

pharynx; P, palp; Ph, pharynx, with thick muscular wall; PW’,

thin-walled, flexible portion of pharynx; ¢, cuticular teeth in an-

terior margin of esophagus. X4o.

A frontal section thru head and anterior segments, with the intro-

vert protruded. Lettering as in Fig. 2. X4o.

Longitudinal section at junction of gizzard and intestine. G, giz-

zard; I, intestine; S, sphincter muscle at beginning of intestine; V,

valvular enlargement at anterior end of intestine. X40.

Fig. 5.

Fig. 6.

Fig. 7.

Fig. 8.

Fig. 9.

Fig. 10

Fig. 11.

T. W. GALLOWAY AND PAUL S. WELCH

Plate II

Ventral view of the head; 1, lateral tentacle of the prostomium; m,

median tentacle; P, palpus; 1, 2, 3, the peristomial tentacles or cirri.

The lower lip is shown to be an anterior projection of the first seti-

gerous segment. XI5.

Longitudinal section thru dorsal body-wall immediately in front of

3rd peristomial (first setigerous) segment, B, brain; E, epithelium;

E’, the thickened sensory epithelium in front of the peristomial

flap (F). X300.

Eye. A median section of anterior eye thru pupil. Cw, cuticula; E,

epithelium; Le, lens; 0. n., optic nerve; Pe, pedicel of the lens; Pg,

pigment layer of the retina; 7, rods, or layer formed by inner ends

of retinal cells; R, retinal cells, deeper portion containing nuclei.

X 330.

Ommatidium. C, the nucleated part of the cell; F, fibre; Pg, pig-

ment, which collectively makes the pigment cup of the eye; 7, the

rod or inner end of cell. 500.

Setae-sac of dorsal bristles, cut in the long axis of the setae. A,

aciculum; c, bristle cell, from which the bristles arise; m, basement

mebrane; s, seta (see also Fig. 16). 125.

Cross-section of two parapodia showing both the dorsal and ventral

bristle sacs cut across the long axis of the setae. A, acicula (the

smaller light objects are the setae); Ci, dorsal cirrus; n, nephrid-

ium; S’, ventral seta-sac; S”, dorsal sac, with the swimming bristles

in two parallel rows. The darker dots show muscular elements. X50.

Cross-section of a segment in the mid-region of the body of a male.

G, glandular part of nephridium; N, the tubular portion of neph-

ridium, much enlarged and used as sperm-ducts; T, the twisted

gland cells (see Fig. 22) numerous in the dorsal body wall. X50.

x be

va’

PEATE it

Fig.

STUDIES ON ODONTOSYLLIS ENOPLA VERRILL RVA

Plate III

Dorsal view of head and anterior body segments. Ey, eyes,

occurring in pairs on flaps; L, lateral tentacles of the prostomium;

M, median tentacle; P, palpus; Ph, introvert protruded; 1, 2, 3, the

tentacles of the three peristomial segments. X15.

Lateral view of the head. Lettering as in Fig. 12. X15.

Sagittal section thru buccal cavity, showing beginning of the

pharynx. JD, dorsal; V, ventral, dt, conical denticles of cuticula in

wall of pharynx; g, a patch of glandular cells in floor of mouth; Ph,

lumen of pharyx.

Gland cells of epidermis. C, cuticula; E, epithelium; g, gland

cell showing characteristic inner reticulated protoplasm and outer

striated protoplasm. 600.

Setae. D, the dorsal, capilliform, swimming setae of the mid-body

region; ’, the ventral jointed setae, occurring the whole length of

the body.

Cross-section of the body in the mid-region of body. (Ci, dorsal

cirrus; J, lumen of intestine; O, ova in body cavity. X50.

Fig. 18.

Fig. 10.

Fig. 20.

Fig. 21.

Fig. 22.

Fig. 22a.

T. W. GALLOWAY AND PAUL S. WELCH

Plate 1V

Cross-section of pharynx and esophagus, with introvert withdrawn.

E, muscular wall of the esophagus, showing the lateral mass of

muscular fibres connected with the tooth apparatus; ep, epithelial

layer that secretes the ventral teeth; Df, a longitudinal, dorsal fold

of the pharynx that invades the front of the esophagus in intro-

version; Ph, muscular wall of the pharynx. X65.

Similar cross-section a little anterior to Fig. 18. X65.

Cross-section in mid-region of body, including a dissepiment (Di).

1, dorsal ramus of notopodium, bearing dorsal cirrus (Ci); 2, ven-

tral ramus of notopodium, bearing swimming bristles supported by

aciculum; 3, dorsal ramus of neuropodium, bearing bristles and

acicula; 4, ventral ramus of neuropodium with no appendages. X50.

Cross-section of body thru the gizzard. A, aciculum; Ci, dorsal

cirrus; m/!, layer of circular muscles of body wall; m2, longitudinal

muscles; Ra, raphe where there is an anastomosis of the fibres of

the annular band of muscle fibres (2) with the innermost layer of

the gizzard. The numerals indicate three successive zones of ele-

ments in the wall: 1, the peritoneum and thin outer muscle layer;

2, annular bands of fibres, much flattened in the direction of the

long axis of the animal suggested by the broken lines; 3, muscular

columns which make up the bulk of the wall of the organ. Within

this is a thin layer consisting of muscles, epithelium, and cuticula.

X65.

“Twisted” glands (phosphorescent?) from epidermis of female. Po,

pore in cuticula; Sg, the gland with constrictions. 680.

Similar glands in the dorsal epithelium of a male specimen. X68o.

Fig.

23.

24.

25.

20.

27.

28.

30.

STUDIES ON ODONTOSYLLIS ENOPLA VERRILL 39

Plate V

Detail of ventral floor of esophagus, longitudinal section, in region

of teeth. Cu, cuticula lining esophagus; Ep, epithelial layer; g,

glandular epithelium in the thin portion of pharynx; ft, one of the

ventral teeth.

Two muscle columns of the gizzard, taken from transverse section of

that organ (see Fig. 21). Lettering in figures 24-28: cb, “circular

band,” a thin sheet of muscle whose fibres encircle the organ; col,

the radial muscular columns whose fibres radiate from the lumen; f,

a fissure separating the halves of one column; mi, thin inner muscu-

lar layer; mo, a thin outer muscular layer; n, nucleated protoplasm

between the outer ends of the half-columns.

Section perpendicular to 24, transverse to the columns and tangen-

tial to gizzard, just as near the outer surface as possible. 320.

Section transverse to the columns (parallel with 25), at a deeper

level. 160.

Section parallel with 24 and 25, transverse to the columns at their

inner end). X160.

Longitudinal section of columns (outer end) at right angle to Fig.

24, showing them as they appear in longitudinal section of the giz-

zard. X160.

Dorsal wall of intestinal tract showing relation of dorsal blood

vessel to it. cil, cilia; d, dorsal blood vessel; ep, epithelial lining of

digestive tract; L, lumen of blood vessel. 360.

Cross-section from mid-body region of a female in which ovulation

has not commenced. JN, glandular part of nephridium; O, ova; W,

the much stretched and thinned dermo-muscular wall. X4o.

THE ETIOLOGY OF TRACHOMA

By H. C. SoLomon

Contributions from the Zoological Laboratory, University of California,

under the direction of Prof. C. A. Kofoid.

Although many attempts have been made to determine the etiol-

ogy of trachoma, it was not until recently that a germ has been

demonstrated that could be considered specific. The early work was

devoted largely to bacterial examinations, and such bacteria as

Staphloccocci, Streptococci, Pneumococci, Xerose bacilli, infleunza

bacilli, and the Diplococci of Morax-Axenfeld were found in the

diseased tissue. None of these forms, however, was finally con-

sidered specific, and for a time the search was given up.

With the demonstration by Schaudinn of Spirochaete pallida as

the cause of syphilis, a new impetus was given to the study, and it

was not long before a body was demonstrated that was considered

as the cause of trachoma. The discovery was made independently by

Halberstaeder and v. Prowazek, and by Greeff.

While the bodies demonstrated have been pretty generally ac-

cepted as the cause of the disease there are still many problems to

be solved. There is a difference of opinion as to what part of the

mass described is the individual germ. Whether the germ is a

bacterium or protozoon is another disputed point. Then there still

remains the life history to be worked out in detail.

This disease seems to be closely related in its etiological factors

to a number of other organisms supposed to be associated with

certain other diseases. These include Cytoryctes variolae (small

pox) Cytoryctes vaccinia (cow pox), Neuroryctes hydrophobiae

(hydrophobia). the supposed organisms of scarlet fever, Molluscum

contagiosum, chicken pest, carp pox, jaundice of the caterpillar,

Lyssa, etc.

Halberstaeder and v. Prowazek, and Greeff claim the distinc-

tion of having first discovered and recognized the trachoma bodies.

For a time the controversy ran high, each apparently describing

different bodies, but now there is hardly any doubt that these inves-

tigators were dealing with the same organisms.

42 H. C. SOLOMON

The technique is of very great importance in this study, and

especially so the staining, and it was due to the difficulties in this

particular that the early investigators failed to detect the organism.

Adequate preparations may be obtained by making smears of the

secretion, by lightly scraping the surface of the infected eyelids or

sectioning the gross tissue removed by an operation. One great

trouble is the presence of other organisms, as there is usually a

mixed infection, and considerable extraneous matter such as pus

cells and leucocytes.

Various methods of staining have been tried, mostly giving

negative results. However the tubercular bacillus method, Loffler’s

stain for flagella, and the Giemsa method appear to give uniformly

positive results. Greeff reports that Heidenhaim’s iron alum haema-

toxylin stain would not show the bodies, but this is the stain Leber

and Hartmann use successfully and I have found it to work well.

The stain most frequently used in this work is Giema’s azur-

eosin. This is the stain used by Halberstaeder and v. Prowazek, and

Greeff, Frosch, and Clausen in their work. The staining by this

method is as follows:

I. 12 parts Giemsa’s eosin solution (2.5 cc. of 1% French eosin

solution to 500 ce. of distilled water).

2) 8 -palts or wazur 1 (1 -1e@00)):

3. 3 parts of Azur II (0.8:1.000).

The three solutions must be well mixed. Then the preparation

should be put in the mixture and kept at a temperature of 37° C. for

6-9 hours, then washed with distilled water, dried with filter paper

and mounted in cedar oil.

In material from fresh cases of trachoma and from experi-

mental cases on Orang Otangs, using the method of staining given

above, v. Prowazek describes his results as follows: Surrounding

the nuclei of the epithelial cells are dark amorphous masses (plas-

tin masses). By careful differentiation and the use of colored light,

there may be seen inside of these masses little red or reddish purple,

round bodies. (Figure 1). These color after the manner of the

nucleolus.

These trachoma bodies (the name was suggested by Greeff)

have an average size of about %4 micron, but they vary from the

THE ETIOLOGY OF TRACHOMA 43

limits of visibility to 1 micron, and it is possible that there are

many beyond the limits of vision. They are seen to multiply by split-

ting and then come to lie two and two, resmbling the arrangement of

the Diplococci. In its usual position the plastin mass surrounds the

nucleus like a cap, but as the little bodies increase rapidly in num-

ber, the plastin mass becomes puffed out, then it splits into little

parts which become absorbed, and the little bodies are found near

the nucleus, and these later make their way out of the cell.

The presence of the amorphous masses and the small bodies is

typical of trachoma, and the morphological characteristics are spe-

cific. Halberstaeder and v. Prowazek, Greeff, Frosch and Clausen,

and most of the men who have worked on trachoma, consider the

small round bodies as the etiological originators (Erreger) of the

disease, while they consider the dark amorphous mass as a reaction

product of the cell of the host. As v. Prowazek describes it: The

virus seizes on the host and after a short time becomes localized in

the cell, where it reproduces. The host cell answers to the invasion

of the virus by the production of a specific, morphologically differ-

entiated substance of the cell, which is closely related to the nuclear

substance or more closely to the nucleolus of the cell. These reac-

tion products are usually found in the ectoderm cells.

There is a difference of opinion as to whether the small round

bodies or the amorphous masses are the germs. Calkins, Lowden,

Williams and Negri look upon the amorphous masses as protozoa,

and the primary cause of the disease. Their work however has been

done on other diseases and they explain the conditions of trachoma

by analogy. On the other hand the men who have done work on

trachoma, including Halberstaeder, v. Prowazek, Greeff, Frosch,

Clausen, Hartmann, Leber, Di Santo, consider the small round

bodies as specific germs, and the amorphous masses as reaction

products.

The authors who see in the amorphous masses the germ of the

disease consider the whole mass as an individual protozoon. There

is considerable constancy in the appearance of these forms, which

would easily lead to this conception, but in old cases of the disease

they are usually absent, while the small bodies may be present. In

support of this theory they describe a uninucleate cell, but on this

44 H. C. SOLOMON

point they are not very definite. It is to be supposed that the whole

mass is considered the nucleus. This mass is so structureless that it

hardly appears probable that it is the nucleus of an organism. It has

also been claimed, though it has never been confirmed, that conju-

gation has been observed; also the formation of cysts. They inter-

pret the small bodies as being idiochromidia, and forming part of

the life history of the organism. This leads to their classification

as rhizopods, in which group the formation of idiochromidia is

characteristic. The work that led to these conclusions was done

on other forms than trachoma, and at present the proof is not very

conclusive that the same cycle is followed in the case of the

trachoma organisms.

v. Prowazek gives the following reasons for taking exceptions

to the foregoing views: (1) In vaccinia the masses can be made to

disappear with a 10-20% solution of NaCl, and yet vaccination can

be successfully performed with the material that is left. The same

results can be obtained after twenty-four hours digestion with

trypsin or pepsin. (2) In vaccinia successful vaccination can be

performed with material in which no Guarneri bodies are microscop-

ically visible. (3) In hydrophobia the Negri bodies are often not

visible in virulent material. (4) Infections can be successfully per-

formed with weakened emulsions of hydrophobia virus that have

been treated centrifugally, while in the liquid thus treated no Negri

bodies were visible, having apparently been cast aside. (5) Finally,

the structure of these bodies speak against their being protozoa, as

they possess no protoplasmic structure, are hyalin, fairly homo-

geneous, and subject to changes that would be considered cell degen-

eration processes rather than stages in the development of a proto-

zoan.

While the criticisms are significant, it must be remarked that

the infectiousness of the material in which no bodies were visible

only shows that it is likely that there only remained the smaller

bodies which we infer are ultra-microscopic. It is true that it is

easier to conceive of the presence of the smaller bodies which in

their largest and visible stage are only I micron in size, as ultra-

microscopic, but this does not preclude the possibility of the larger

bodies existing in this state, especially after treatment.

THE ETIOLOGY OF TRACHOMA 45

The fact that when treated centrifugally the virus still retained

its virulence might possibly be explained by the fact that some of

the bodies are so light that the centrifuge had no effect on them, or

perhaps some of the virus might have stuck to the side of the con-

tainer. This seems probable when it is considered that in chicken

pest it has been found that a solution of 1-1,000,000,000 of the virus

retains its virulence.

Now to take up the contention that the small bodies are the

germs of the disease. In vaccinia of the cornea of the rabbit, v.

Prowazek was able to trace in the epithelial cells and less frequently

in the Guarneri bodies themselves, little alveoles in which were

minute oval or round bodies, which he designates as initial bodies.

Division was described in some of these at times as binary and in

other cases as multiple spore formation. The same bodies were also

seen by Hartmann, Paschen and Mihlers and considered by them

as the organisms of the virus.

Paschen found in vaccinated children many vaccine bodies in

the lymph of the pustule, and besides these many that divided

binarily, remaining connected by the ends, and these again divided

forming a chain. These finally separated forming little round bodies

with a thread like flagellum hanging to them.

Babes found similar bodies in hydrophobia, while Negri and

Velpine could differentiate little nuclear like bodies in the Negri

bodies and their alveoles. These lay arranged symmetrically around

a central body that could not be differentiated. v. Prowazek sug-

gests that they probably came from this by multiple division.

So here in these other diseases we find a condition somewhat

similar to that found in trachoma. Thus we are able to interpretate

trachoma as caused by a related etiological factor.

According to v. Prowazek, trachoma is a disease of the epith-

elium. On the introduction of the virus into the eye, the epithelial

cells of the conjunctive enlarge. This growth continues with the

increase of the virus, and finally the cell is ruptured and the germs

spread out over the pus. After this the disease can be spread

by purely mechanical means, through contact with the pus cells

By the bursting of the cells the surface layers come to be covered

with the germs. A few little bodies may then reach the follicles, a

46 H. C. SOLOMON

condition which is usually considered as the primary stage of the

disease but which according to this author is the secondary result due

to rapid growth. In the follicles one also finds epithelial cells, and

consequently the bodies may be found there, as it is in the epithelial

cells that they are primarily localized. It is only in the old cases

that the free bodies are found, probably due to the cells containing

them having been destroyed.

Leber and Hartmann, staining with Heidenhaim’s iron alum

haematoxylin, show a light court or ring surrounding the trachoma

bodies which is colored by the Giemsa stain. (Figure 2). This

light ring is interpreted as cytoplasm, while the dark body is con-

sidered as the nucleus. They describe division as follows: The

dark body in the centre divides forming two small bodies, but these

move a short distance apart, remaining connected by a thread. In

moving apart the light surrounding mass (cytoplasm?) is pulled

along, and the result is a dumb bell shaped figure. (Figure 3.)

These figures are very similar to those of Babesia of the tick fever

in the dividing stage. These authors claim that after the entrance

of the trachoma bodies into the cell, chromatin material is thrown

out, and this changes to plastin, and while it is not probable that all

the plastin material is formed from chromatin, at least a part of it

is. This formation is typical of cell degeration, as has lately been

shown by R. Hertwig, Hartmann, and Reichow working on other

forms.

The trachoma bodies increase rapidly in number until they come

to fill up the entire space of the cytoplasm of the cell. (Figure 4))

This increase in the number of the trachoma bodies has a destruc-

tive effect on the cell. The nucleus is forced to the edge of the

cell (Figure 5) and finally destroyed (Figure 6). In this way the

cell is destroyed and after its destruction the bodies come to lie

free, and may get into the pus or on the surface of the conjunctiva.

There seems to be little doubt that the bodies described are the

germs of the disease, and the amorphous masses reaction products

of the cell. It might be added that the trachoma bodies have been

described in the nucleus (Figure 2) and lying free in the cell in

the early stages, apparently before the reaction product had been

formed. In the destruction of the cells and the irritation caused

THE ETIOLOGY OF TRACHOMA 47

by these bodies, there is ample explanation of the ravages of the

disease. Besides this when we consider that in all fresh cases, the

presence of the bodies is constant, and that their morphology is

always the same, we add one more point in favor of this view.

Furthermore these bodies have never been found in any other form

of eye disease. All forms of conjunctivitis and infections of the

eyes have been examined, but the results have all been negative.

A point that has caused a great deal of doubt is that after

filtration through the finest Berkfeld filter under pressure, the

filtrate was found to be infectious, although no bodies were visible.

The explanation of this phenomenon is that the smaller ultra-micro-

scopic bodies passed through the filter, but this is purely hypo-

thetical. Prowazek, working on chicken pest, which presents the

same problem, has been able to clear up the matter. He has shown

that by using a Berkfeld filter and filling the pores with agar,

celloidin and gelatin that the filtrate was no longer infectious. In

the gelatinous mass he found the broken bodies of the germs.

In cases that have been treated and in old established cases

no trachoma bodies have been found. Greeff has shown in at least

one case that at a certain stage the disease is not infectious, but

unfortunately he does not state whether or not the trachoma bodies

were present. The indication seems to be that there is a stage in

the life cycle of the germ when it is not present in the form

described. Another fact suggestive of the life history, is that the

disease is recurrent (recidiv). After an apparent cure that has

lasted some time, the disease suddenly comes back in full vigor,

when there was no apparent new infection. This is a very important

consideration in the matter of the suppression of the disease, and

probably accounts for the great number of cases that slip into this

country despite the care of the United States Public Health and

Marine Hospital Service. In this respect it reminds us of the

action of malaria, and it is interesting to note that in 1897 Elze

published a paper trying to show the relation of trachoma to the

Plasmodium of malaria.

Many experiments have been made to grow the germ in cul-

ture. The secretion has been planted in: (1) Different fertile soils;

(2) on boullion; (3) on agar, weak and strong; (4) on glycerin

48 H. C. SOLOMON

agar; (5) on blood agar; (6) on Loffler’s blood serum; (7) on

serum agar; (8) on soils free from acids. The contents of follicles

were also planted in the soils. On no occasion were the trachoma

bodies obtained. This does not mean that they cannot be grown in

culture, but rather that the right conditions have not been tried.

Although only negative results were obtained in the attempts

to grow the germ in culture, they have been grown in culture

animals. Halberstaeder and v. Prowazek succeeded in infecting

Orang Otangs and obtaining the typical trachoma bodies. Positive

results were not obtained on all occasions, even on repetition; this

was so both when the secretion and the follicles themselves were

used for the inoculation. There is a possibility that the virus was

not all retained, but was washed away by the lachrimation. There

is also a possibility that some of the animals were naturally immune,

and also that the cases from which the virus was taken were not

in an infectious stage of the disease.

Innoculation experiments have been made on other animals,

both for the purpose of attempting to get material for experimen-

tation and also for hygienic considerations. Experiments have been

made to inoculate rabbits, guinea pigs and dogs, but with negative

results. However Greeff remarks that he remembers seeing a dog

that apparently had trachoma, the eyes presenting all the clinical

symptoms; and Dr. Kunz reports a dog kept in the trachoma bar-

racks at Thorn afflicted with the disease. In both of these instances

_ however, no microscopical examinations were made to find the

trachoma bodies.

Greeff was unable to infect the Macacus apes, while the Italian

investigators, Baiardi and Bertarelli, and Cecchetto obtained positive

results both on the Macacus and Cercopithecus. The time that

elapsed before it became certain that the infection was successful

varied from two weeks to three months. The fact that these investi-

gators working in Italy were able to get successful inoculations,

while Greeff in Germany was unsuccessful with the same species,

suggested that climatic conditions may have something to do with

the infectiousness of the virus.

Successful inoculation were performed on the Cynocephalus

(Pavinae) apes by Hess and Romer, Greeff, and Dr. Hereford.

THE ETIOLOGY OF TRACHOMA AQ

The latter stated that after a time the symptoms began to disappear

and five weeks after the inoculation had disappeared entirely.

This suggests that the disease may run in a cycle, or that the culture

animal had a high resistance.

A fact that seems pertinent in regard to these experiments on

animals is that even in cases where it was apparent that the infec-

tion had taken, the condition of the conjunctiva was different from

that in man. The inflammation was not so great and there were

no infected follicles present in the manner so characteristic in human

cases. Greeff remarks that ‘while the conjunctiva reacts to the

trachoma virus, the condition of the susceptibility and in the struc-

ture of the clinical pictures there is established a great difference

between man and animals. Perhaps it is the same as we have

learned in the case of the syphilis virus, that the animals give a

lesser susceptibility as against a greater in man.”

Greeff has performed two inoculation experiments on humans.

In the first case no results were obtained. There could be no doubt

that the person from whom the virus was taken had the disease.

Two possibilities present themselves to explain the failure of the

experiment :—either that the person on whom it was made was

inherently immune to trachoma, or that the period of infectiousness

had been run. Greeff offers the latter explanation. It is the general

opinion of clinicians that the disease has its periods of infectiousness,

and after this has been run that it is no longer infectious. That the

virus from the eye of this patient of Greeff's experiment was at

one time infectious seems certain, as two members of his family

had apparently caught it from him previously.

In the second case the results were distinct. On the second day

after the inoculation there was a reddening, swelling and secretion

of the left eye, but the difference between the two eyes was slight.

Five days later there was a swelling of the lid, slight swelling of

the conjunctiva, and a slight secretion, the two eyes being well differ-

entiated. Three days later there was a distinct swelling of the lid

and conjunctiva with the formation of follicles. The next day the

eye was running, the lids heavily swollen, the conjunctiva very red,

and folds and follicles formed, presenting a typical trachoma pic-

ture. The microscopical examinations showed no cell inclusions

50 H. C. SOLOMON

until the thirteenth day, when the first were visible. After this they

increased rapidly.

From these results we can draw the following conclusions:

Trachoma is a specific infectious disease; it is transmissable by

purely mechanical means, without the presence of an intermediate

host; there is no acute or initial stage of the disease, differentiated

from a secondary or tertiary stage as in the case of syphilis since

trachoma develops completely in a few days. The fact that with

the introduction of the virus the trachoma bodies, cell inclusions,

are brought into the conjunctiva, which before was free from these,

speaks strongly for the conception of these bodies as the specific

germ of the disease.

The question as to susceptibility and immunity to this disease

has often been raised. Is there any such thing as disposition of a

race as a whole to this disease? The only fact seeming to have any

bearing on this question is that the negroes in North America seem

to be immune from it. As far as is known no case has ever been

reported among them. On the other hand in Europe and Asia it is

found to a great extent among the colored races, and in Africa it is

very prevalent, Egypt seeming to have been its original home. On

the whole it may be said that race has no proved significance in

this connection.

It is interesting to note that children up to the age of two or

three years seem to be immune. At least no cases have been noted

in very young children, even when they have been suckled by

mothers having the disease.

It has been stated that persons having gonorrheal infections

of the eyes are immune, but this is not so. It has also been said

that scrofula prepares the eye for trachoma infection, but there

is no proof of this. Of course a person in this condition may be

highly susceptible as there is a favorable condition for the retention

of the virus, if brought into contact with the eye.

It has been contended that when one eye is infected the other

becomes immune. It is true that it is usually found only in one

eye, but the reason probably is that after one eye becomes infected

the patient becomes more careful and keeps the other eye clean.

Personally I have seen a case in which both eyes were infected.

THE ETIOLOGY OF TRACHOMA SI

Germaix tried infecting the free eye with the virus of the other, but

was unsuccessful. This however does not prove anything as it is

possible that he took the virus from an eye in which the infectious

stage had been run.

People whose blood contains a large amount of haemoglobin

are more likely to escape the disease. Anemia and the presence of

CO2 are favorable for the disease.

In the lowlands and swampy regions the disease is especially

prevalent, while in the highlands it is less often found. This is due

in a great measure to the conditions found in these regions. In

the swampy countries there is a greater amount of CO2 which is

favorable to the disease, and dampness is also a favorable condition.

In the highlands the conditions are less favorable for the disease as

the people are found to have more haemoglobin in the blood and

less CO2 as a rule.

It is probable that climatic conditions influence the virility,

the re-occurrence and the infectiousness of the disease. While it is

not found exclusively in any one place, it has been longest and best

known in Egypt, a warm country. It is also noticeable in the

clinics that the disease is less frequent in winter, and that with the

return of the warm weather, new infections or re-occurrences come.

There can be little doubt that trachoma is a germ disease, or

that the germ is present in the morphological structures described.

Our knowledge of the subject points to the so-called trachoma

bodies as the germ, rather than the larger amorphous masses. The

point then remains, is the parasite a protozoon or bacterium?

Halberstaeder and v. Prowazek claim that the parasites are

protozoans, while Greeff, Fresch and Clausen claim that they are

bacteria. In support of the theory that they are protozoans are the

following facts: (1) The disease and also the related diseases run

in cycles so characteristic of protozoan diseases. It has been noticed

that there is a re-occurrence after an apparent cure without a new

infection. (2) The trachoma bodies are intracellular. The only

cases of bacteria that are intracellular are the leper bacilli described

by Babes, but this is strongly opposed by Sudakowitsch; and the

Gonococci, whose intracellular nature is now explained as due to the

action of phagocytes. (3) They have also been found in the nucleus,

52 H. C. SOLOMON

a condition that has never been observed in the case of any bac-

teria. (4) They give certain reaction products that can be traced

morphologically, and by staining, to the stainable matter of the

nucleus (chromatin and nuclein). (5) They can not be grown in

culture media as can the bacteria. (6) They are very adaptive,

changing according to the environment. (7) They give new quali-

ties to their host. (8) Gall and gall salts, which have no effect on

bacteria, destroy their virulence. (9) The division as pictured by

Leber and Hartmann, shows a condition analogous to that in forms

of protozoa, especially as observed in amoeba and flagellates. (10)

They are similar morphologically to forms of protozoa found para-

sitic in amoeba. (Figure 7). (11) They are smaller than any

known bacteria.

Greeff, who considers them as bacteria, says that the fact that

they have not yet been grown in culture does not prove that they

are not bacteria, but that the right medium has not been found.

Further he argues that the smallness of the body is no criterion as

Frosch has shown some bacteria equally as small. Unfortunately it

is not stated what these bacteria are. Another point that he empha-

sizes is that the double form is characteristic of the bacteria; but with

binary fission this form would be seen in any case.

I think that the evidence now at hand greatly favors the

contention that the body is a protozoon. There still remains the

question of their classification, but with our present meagre knowl-

edge of the subject little can be said. They are undoubtedly closely

related to the germs of the other diseases that were mentioned as

being closely related to trachoma. Prowazek creates a new group to

put these forms in, calling them Chlamydozoa, i. e., mantle bearers

(referring to the fact that they surround the nucleus in the form of

a cap or mantle) and placing this group midway between the bac-

teria and protozoa.

What can be said as to the practical application of the trachoma

bodies in the diagnosis of trachoma? In new cases that have never

been under treatment the presence of these bodies is constant and

specific for this disease, but in most cases there is little need to

make so complicated an examination as the clinical picture is typical.

In old cases, or cases that have been under treatment, the bodies

THE ETIOLOGY OF TRACHOMA 53

disappear, and then while the patient might be suffering from

trachoma, this form of diagnosis would be contradictory. It may be

said that this method is only confirmatory and not sufficient in itself,

When the results are positive there can be no doubt that trachoma

exists, but when these bodies are absent the disease may still exist.

Through the kindness of Dr. A. Barkan, in charge of the eye

clinic of the Cooper Medical College, I was enabled to obtain ma-

terial from trachoma patients. This material was used to demon-

strate the etiological factor of the disease and to experiment on the

susceptibility of animals. The work was done in the laboratory

of the Department of Zoology of the University of California, with

the following results.

Material was obtained from the eye of a man, forty-five years

of age, who claimed that his eyes had never before been treated.

Smears of the secretion of the eye were made, the contents of

follicles were spread upon cover glasses, and sections were made

from the conjunctiva obtained from an operation. These prepara-

tions were stained with the Giemsa stain and some with Heiden-

haim’s iron alum haematoxylin.

Examination of the preparations stained by the Giemsa method

showed many pus cells and leucocytes present in the sectioned ma-

terial. Many small eosinphile granules were also present. In the

parts of the sections showing but few pus cells or leucocytes the

trachoma bodies were found. These, as described above, were

minute deeply staining bodies, lying in a structureless amorphous

mass. These were occasionally found surrounding the nucleus, but

most often they were to be seen lying free outside of the cells in

rows, with the amorphous masses broken up and persisting only

occasionally. These bodies showed also in the other preparations

and with the iron alum haemotoxylin stain.

Other material was obtained from the eye of a Chinaman from

the secretion and by opening follicles. It was found, however, im-

possible to demonstrate any trachoma bodies. In this case it was

discovered that the patient had been under treatment before, and

as has been stated above, in sttch a case the bodies do not seem to

be present. The question however arises as to what has become of

the bodies. When the patient was brought into the clinic, it ap-

54 H. C. SOLOMON

peared that the disease was in a virulent condition, and apparently

rapidly getting worse. Now if these bodies are the direct cause of

the disease why should they be absent in such a condition. The

answer may be given that they may be present and in ultra-micro-

scopic condition, or that while the body of the germ has been de-

stroyed a toxin has remained. These explanations, however are

purely theoretical, and more information is necessary before we

can give a definite explanation.

Attempts were made to infect guinea pigs, white rats, and a dog,

with the disease. The virus for these experiments was obtained

from a patient with trachoma who at the time that the virus was

obtained had never been under treatment for her eyes. The results

were all negative. The eyes of the inoculated animals showed no

clinical symptoms of the disease and the microscopical examina-

tions were also negative.

BIBLIOGRAPHY

Archives of Opthalmology, vol. 38, 1900.

CLARK AND SCHERESCHEWSKY.

Trachoma, Its Characters and Effects. Public Health and Marine Hos-

pital Service, U. S., 1907.

CLAUSEN.

Untersuchungen tiber die Enstehung und die Entwicklung des Trachoms.

Klinischen Jahrbuch, 1908.

Beitrage zur Trachom Forschung. Klinischen Jahrbuch, 1909. Inhalt-

verzeichnis :

a. Die Uebertragbarkeit des Trachoms. Prof. Greeff.

b. Untersuchungen zur Aetiology des Trachoms, Leber und Hart-

mann.

c. Untersuchungen tiber die sogenannten Trachomkorperchen. Dr.

C. Di Santo.

d. Wie sind die Sogenannten Trachomkorperchen differential-

diagnostisch zu verwerten. Dr. Clausen.

e. Die Einschleppung des Trachoms in den Regierungsbezirk

Arnsberg. Prof. Greeff.

THE ETIOLOGY OF TRACHOMA 55

KeR EL ZE:

Plasmodienbefunde bei Trachom, 1897.

GIEMSA UND PROWAZEK.

Weitere Untersuchungen tiber sog. ultramikroskopische Infektionserreger.

| Miinchener med. Wochenschr., No. 29, 1908.

HALBERSTAEDER UND PROWAZEK.

Zur Aetiologie des Trachoms. Berliner klin. Wochenschr., No. 24, 1909.

Zu dem Aufsatz “Die Erreger des Trachoms” von Prof. Greeff. Deut.

med. Wochenschr. No. 17, 1900.

PROWAZEK UND DE REUREPAIRE.

Untersuchen tiber Variola. Miinchener med. Wochenschr. No. 44, 1908.

S. von PROWAZEK.

Chlamydozoa I, Zusammenfassende Ubersicht. Arch. fiir Protistenkunde

10, 1907.

Bemerkungen zur Kenntnis der pathogen Mikro-organismen ‘“Chlamy-

dozoa.”’ Miinchener med. Wochenschrift No. 19, 1908.

EXPLANATION OF FIGURES

Fig. 1. An epithelial cell with a few trachoma bodies surrounding the nucleus.

Fig. 2. Trachoma bodies surrounded by light court as figured by Leber.

Fig. 3. Division of trachoma bodies as figured by Leber.

Fig. 4. Cell in which trachoma bodies have greatly increased in number.

Fig. 5. Nucleus being crowded to edge of cell.

Fig. 6. The destruction of the cell, the nucleus having disappeared.

Fig. 7. An Ameba infected with protozoan parasites. (After Calkins).

DEPARTMENT OF SUMMARIES

TO BE DEVOTED TO DIGESTS*OF PROGRESS

IN: BIOLOGY ~

While the Transactions will continue to be primarily a Journal of research in micro-

biology, it is recognized that the field has become so broad as to preclude the possibility

of frequent articles in any one of the departments of special interest. Because of this

it will be the policy to present, from time to time, supplementary digests of the progress

being made in the various fields of micro-biology. It is also proposed to introduce similar

summaries of the progress made in some departments not represented in our articles of

research. This is done with the feeling that such reviews will increase the permanent

value of the Transactions to all who may not have access to a large list of technical

biological journals, nor the time to make the survey for themselves.

THE THEORY OF NERVE COMPONENTS AND THE

FORE BRAIN VESICLE OF VERTEBRATES

By F. L. LANDACRE

A critical review of the two recent papers on the fore brain

vesicle of vertebrates by J. B. Johnston (4) and C. J. Herrick (3)

would be out of place in a short sketch. They should be consulted

by those caring to follow the descriptions and arguments on which

their conclusions are based. Several points in these papers have an

important bearing on the theory of nerve components and a dis-

cussion of these in connection with some of the more general con-

clusions of that theory may not be inopportune for those whose

interest in other fields of work preclude their following closely the

development of the theory and its implications.

The theory of nerve components in its narrow sense, and as

first worked out, applies primarily to the composition of the cerebral

nerves. It has, however, extended its field until it involves not only

the peripheral nerves and sense organs, but the fundamental struc-

ture of the cord and brain as well as the embryology of all these

structures. It has gradually been enlarged into what has been called

a functional morphology of the nervous system by applying to the

58 F. L, LANDACRE

whole nervous system principles first applied to limited parts of

that system.

The significance of the theory is, however, most apparent from

a statement of the facts upon which it was founded.

Any one who has had occasion to consult the neurological lit-

erature of the last decade preceding 1900, must have been struck

by the diversity of opinion and often by the hopeless lack of agree-

ment as to the homology of the cerebral nerves in the various classes

of vertebrates. Coupled with this disagreement as to the homology

of the cerebral nerves was disagreement as to the more fundamental

problems of head morphology, particularly the problem as to the

number of head neuromeres and the relation of these to the cerebral

nerves and of the cerebral nerves to the spinal nerves.

Now while these fundamental problems are of the greatest in-

terest and of far reaching importance to the vertebrate morphology,

the question arises as to whether the point of view from which

the work was done might not have had some fundamental weakness

about it that prevented agreement among workers.

The dominant note, in the writer’s estimation, in the neurolog-

ical work of the period mentioned, was the serial homology of the

central and peripheral nervous systems; not always the avowed

object of research of course, but the dominant idea by which most

morphological conceptions were tested.

Starting with the two-root segmental spinal nerves, the effort

was made to unravel the cerebral nerves on the basis of their rela-

tion to the spinal nerves ; to determine the number of head segments ;

to place the cerebral nerves in their proper segments and to deter-

mine the homology of the cerebral nerves to each other in the vari-

ous groups of vertebrates. The aim was purely morphological and

its weakness as a working hypothesis became most apparent in the

effort to determine the homologies of the cerebral nerves with the

two root theory and serial homology as the fundamental ideas back

of the analysis. Much of the morphological work was extremely

valuable and necessary to the solution of problems in head mor-

phology which we shall have with us for a long time to come, and to

which we must return from time to time and attempt to solve from a

THE THEORY OF NERVE COMPONENTS 59

different standpoint, and after the acquisition of new material bear-

ing on these problems.

The essential weakness of any purely morphological conception

as a working basis lies in the fact that it fails to take cognizance of

the fact that an organism is primarily a living thing; that there are

certain processes that it must carry on to meet the requirements im-

posed upon it by its environment and that no structure, however

perfect anatomically, can persist and become a permanent part of

the organism, if it does not do the work demanded of it. In short,

what an animal has to do and the way it does it are more important

and furnish a better working basis in the attempt to understand its

nervous system, than the serial homology of its parts or any other

purely morphological conception that ignores the function of the

structures concerned. The primitive morphological characters of

the nervous system may be modified almost indefinitely so long as

they serve the primary functions of conduction and correlation that

adjust the organism to its environment.

These criticisms of the early workers in neurology do not apply

to them only, for their morphology was exactly in line with the

morphology of the time. It had the same strength and the same

weaknesses that the purely morphological conceptions in zoology

and embryology had. The parallelism goes further. The general

adoption of the experimental method in general zoology and embry-

ology was coincident with the appearance of the theory of nerve

components and a functional analysis of the central and peripheral

nervous systems of the vertebrates. This I take to be the deeper

significance of the recent work on the nervous system whether it

is strictly experimental or not ; not so much to ignore morphological

conceptions as to make them of secondary importance to functional

conceptions. It amounts to determining the simplest conduction

paths in the lower vertebrates and following the elaboration of these

paths in the more specialized higher forms, the conduction path be-

ing primarily the expression of an important functional fact.

Take for instance Gaskell’s (1) treatment of the typical spinal

segment. Instead of the old two-root theory which was a most

serious handicap to the correct interpretation of the homologies of

the cerebral nerves, he finds four roots; two somatic and two vis-

60 F. L. LANDACRE

ceral, with a sensory and motor component in each. This gives us

four roots to each segment and four centers in the cord. The terms

used to designate these components, somatic and visceral, are of

course morphological as are their homologues in the brain; but the

significance really lies in the fact that the visceral sensory and

visceral motor components are concerned in reflexes involving the

adjustment of internal organs to each other, while the somatic

motor and somatic sensory components are concerned in reflexes

involving the adjustment of the organism to its external environment

through external stimuli and by means of somatic muscles concerned

chiefly in locomotion.

By conceiving of these four centers of each segment as arranged

in longitudinal columns, we can speak of a longitudinal analysis

of the cord, even though the centers may not be continuous as cell

masses in consecutive segments. This conception of longitudinal

columns of the cord and brain, while it does not clear up some

of the difficulties encountered by the students of transverse seg-

mentation of the brain, furnishes us with a far more valuable con-

ception with which to attack the fundamental problems of the cord

and brain. It shows how simple generalized reflexes have been

elaborated into highly specialized reflexes, particularly those of the

special senses and of the higher types of conduction paths of the

higher mammals.

This idea was first clearly enunciated for the brain by Johnston

(5) on the basis of his study of the brain of the sturgeon. Here we

find an almost diagrammatic arrangement of the four columns with

a marked continuity throughout the length of the medulla. The

simplicity of arrangement is due in part to the hypertrophy of the

columns and in part to the widening of the central canal of the cord

into the fourth ventricle. From the medulla the columns extend

forward into the regions anterior to this with varying degrees of

continuity ; the important segmental nuclei of the metencephalon, the

mesencephalon and the diencephalon being referable to these four

columns. The conduction paths are important in determining the

exact relation of important regions in the segmental portions of

these three brain divisions and the supra-segmental centers are refer-

able to correlation tissue present to a greater or less extent in

segmental centers.

THE THEORY OF NERVE COMPONENTS 61

The older morphology sought to place these centers in their

proper places in the transverse segmentation of the brain, an effort

that met with indifferent success and when successful gave us little

clue to the functional significance of the centers. The newer mor-

phology inquires primarily as to which of the four functional

divisions, as shown most distinctly in the medulla, a particular

nucleus or tract belongs, and concerns itself only secondarily with

its place in the transverse segmentations of the head, since its rela-

tion to one of the four functional divisions determines its position

functionally and serves to explain the significance of the secondary

and tertiary reflex paths in the brain.

Turning now to the cerebral nerves, to which the theory of

nerve components was first applied in its narrow sense, we find that

the first analysis of the cerebral nerves on the basis of their com-

ponents or functional units was made by Strong (6) on an am-

phibian. This analysis was very thorough for the trigemino-facial

complex. Somewhat later a very thorough analysis of all the cere-

bral nerves in a teleost was made by Herrick (2) accompanied by

a full description of the central connection and peripheral distribu-

tion of these nerves. The basis upon which this analysis was made

is the difference in size between the fibres of the various compon-

ents such as the ear and lateral line or acoustico-lateralis component,

the general cutaneous or tactile, and the visceral including both

special visceral or gustatory and the general visceral supplying

mucous surfaces. The analysis is simplified in some types by a com-

plete isolation of ganglia which are usually fused in other types and

especially by the hypertrophy of certain of these systems—in some

types one, and in other types another—so that the course of a given

component can be traced from its origin in its ganglion to both its

central and peripheral terminations. This last principle of using

hypertrophied systems has been emphasized and used, particularly

by Herrick, in the solution of difficult problems in the morphology

of the brain and nerves. It practically amounts to selecting a type

in which nature has performed an experiment for us, as for instance

in the case of the enormously hypertrophied gustatory system of the

catfishes where this system is so large in proportion to other systems

that both its peripheral nerves and central connections can be fol-

62 F. L. LANDACRE

lowed with comparative certainty. A great deal of attention has

been paid in nerve component work to the analysis of V, VII, VIII,

IX and X nerves, particularly their sensory components because

these, excepting the VIII, are compound nerves. The III, IV and

VI are pure motor nerves and easily referable to the somatic motor

group and I and II stand, in a sense, in a class by themselves owing

to their mode of development. These nerves are amenable to the

same classification, the I being placed in the visceral sensory and the

II in the somatic sensory division. These will be referred to later.

Without attempting to give in any detail the distribution of the

three components mentioned, the general cutaneous, the acoustic-lat-

eralis and the visceral in the cerebral nerves, the general statement

may be made, taking the ganglia as a starting point, that in the

Ichthyopsida the V ganglion furnishes only general cutaneous or

tactile fibres. The VII ganglion furnishes, from two of its div-

isions, lateral line fibres and from a third division visceral fibres both

special gustatory and general. The VIII ganglion furnishes only

auditory fibres referable phylogenetically to the lateral line group.

The IX ganglion contains in Ameiurus apparently a pure special

visceral portion whose fibres supply taste buds and a lateralis gan-

glion. The X contains all four components.

The way in which these components are distributed in any given

cranial nerve trunk is quite variable. A particular nerve in two

different types retains its integrity only in a general way, the degree

of variability depending largely upon the dominance of one or the

other of these components. So that nerves vary not only in the

relative amount of any one of these components and consequently

in their mode of peripheral distribution but vary absolutely also by

containing components in one type which are absent in another. The

peripheral organs to which any one of these components is dis-

tributed are constant, as are their central connections in the brain,

and these central connections are referable to the four longitudinal

columns mentioned earlier.

The most obvious conclusion from a study of the analysis of

the cerebral nerves is that the units of which the cerebral nerves are

made up are the components and not the nerves themselves. Any

given cerebral nerve if studied in a number of types is likely to

THE THEORY OF NERVE COMPONENTS 63

show a variation in its distribution owing to the fact that it does not

have a constant structure. The cerebral nerves are more like routes

from the periphery to the brain in which the units of conduction

vary. The components consequently become the units in our analy-

sis of these cerebral nerves and the term nerve-component becomes

extremely valuable as a constant reminder that we must start with

these as a basis in our attempt to analyze the cerebral nerves rather

than the segmental position of the nerve, with reference to head

neuromeres. The determination of the precise segmental position

of a given cerebral nerve would be an interesting morphological fact

if we could ascertain it exactly, but is relatively unimportant com-

pared with an accurate knowledge of the functional divisions or

components of the nerve which enable us to determine what kind of

reflexes must be served by this nerve, and the part it plays in the

economy of the body as a functioning organism. The theory of

nerve components looks toward an explanation of how the nervous

system works.

The interesting question of the relation of the head to the trunk

is not ignored in the theory of nerve components, although it is

approached from a different point of view. The terms “general

cutaneous” and “general visceral’ applied to fibres in the cerebral

nerves that do not end in special sense organs, indicate the funda-

mental similarity of these in both brain and cord. This conclusion

is further strengthened by the similarity in mode of origin of the

two components in the brain and cord, these coming from the neural

crest in both cases.

The relation of the special somatic components of the cerebral

nerves, in which class the acoustico-lateralis and optic fibres fall

and of the special visceral, in which class the gustatory and olfac-

tory fibres fall, is not quite so simple. These classes of fibres

receive their name from the fact that they end in the cord and

brain in centers homologous to the visceral and somatic centers of

the cord and are special in the sense that they end in specialized

organs. They differ from spinal nerves in the fact that there are in

present Ichthyopsida no homologues of the special sense organs in

the trunk innervated by spinal nerves and that the specialized gan-

glia arise in a manner totally different from the spinal ganglia. The

64 F. L. LANDACRE

fact that the centers in the brain are homologous to those of the

cord enables them to be placed in the same general category from a

functional standpoint.

Whatever may prove to be the explanation of the origin of

the special sense organs and of the special ganglia, the reference of

the special components of the cerebral nerves to the two compon-

ents represented in the cord is a marked step in the direction of a

rational interpretation of the marked cephalization of the verte-

brates.

Returning now to the brain axis, we find the attempt made in

the two papers mentioned to carry the analysis of the brain stem

into the diencephalon and telencephalon. Prof. Johnston has given

his attention mainly to the question as to the exact delimitation of

the first two segments, while Prof. Herrick has taken up the question

of the extension of the four longitudinal columns into the first two

brain segments.

Both these papers contain suggestions for changes in the B. N.

A. subdivisions of the diencephalon and telencephalon. The bear-

ing of the papers on the analysis of the brain axis into logitudinal

columns, only, can be taken up here.

In the diencephalon the six primary laminae of His, i. e., the

roof plate, the floor plate and two lateral plates on each side become

ten according to Herrick. The two lateral plates of His which are

separated by the longitudinal furrow, the sulcus limitans, are divided

into four longitudinal regions by two additional furrows. The two

dorsal columns of these four lateral columns are devoted mainly to

receptive functions and the two ventral columns to effector func-

tions. The ventral columns contain chiefly the descending conduc-

tion paths and the dorsal the ascending conduction paths. The

sulcus limitans disappears in the diencephalon and its disappear-

ance is probably correlated with the absence of motor nerves

anterior to the mid-brain and to the invasion of the remaining

motor coordination tissues by visceral elements. The evagination of

the optic vesicle occurs in the dorsal lamina. The boundary between

the diencephalon and telencephalon is placed by Johnston on a line

running from the velum transversum to the chiasma. This leaves

a median unpaired portion in the telencephalon in addition to the

THE THEORY OF NERVE COMPONENTS 65

paired portions evaginated from the brain axis and surrounding the

first and second ventricles.

Prof. Herrick’s analysis of the telencephalon is based upon the

adult amphibian and the embryonic brains of vertebrates generally.

The four lateral columns of the diencephalon are evaginated

to form the hemisphere but owing to the meeting of the roof and

floor plate of His in the lamina terminalis or rostral end of the

brain, the columns situated at the extreme dorsal and the extreme

ventral parts of the lateral brain wall approach each other and are

shifted in position so as to meet on the medial wall of the lateral ven-

tricle leaving the lateral wall to be formed by the two middle col-

umns of the diencephalon.

The two ventral laminae are directly continuous with the ven-

tral columns and are concerned in efferent functions, the ventro-

medial in visceral efferent and the lateral in somatic efferent func-

tions.

The two dorsal laminae correspond to the two dorsal laminae

of the diencephalon but direct continuity between the two regions of

the brain is interrupted in forms above fishes by the great flexure

between the diencephalon and telencephalon. The olfactory bulb

was the site of the initial telencephalic evagination, but later in

phylogeny all four columns become involved and there was also

much differentiation in situ. The later stages of the telencephalon

were dominated by the entrance of tracts for the correlation of

olfactory sense with tactile and visual sensations and as we ascend

the phylogenetic series the non-olfactory correlation tissue domi-

nates more and more the functions of the telencephalon.

The significant fact about both these papers is not so much

the explanation of later stages of the first brain vesicles, although

that is significant, as the reduction of them to a simple type which

brings them into line with other parts of the brain axis and renders

clear the analysis of the whole brain axis from a functional stand-

point. It is a significant step in the process of rendering intelligible

the most puzzling field in vertebrate anatomy.

KF. L. LANDACRE

BIBLIOGRAPHY

GaSsKELL, W. H.

On the Structure, Distribution, and Functions of the Nerves which Inner-

vate Visceral and Vascular Systems. Jour. of Phys. Vol. 7, 1886.

Herrick, C. J.

The Cranial and First Spinal Nerves of Menidia. Jour. of Com. Neu.

and Psy. Vol. 9, 1800.

The Morphology of the Forebrain in Amphibia and Reptiles. Jour.

Com. Neu. and Psy. Vol. 20, No. 5, 19Io.

Jounston, J. B.

The Morphology of the Forebrain Vesicle in Vertebrates. The Journal

of Com. Neu. and Psy; Vol. XIX No. 5, 1900.

The Brain of Acipenser. Zool. Jahrbtcher. Vol. 15, 1901.

Strone. O. S.

The Cranial Nerves of the Amphibia. Jour. Morph. Vol. 10, 1895.

NOTES, REVIEWS, ETC.

A PLEA FOR MICROSCOPY, AS A STUDY AND A HOBBY

Such general terms as Naturalist, Student of Nature, or Micro-

scopist have a peculiar value in these times of specialization. It is

worth while at this time to dwell somewhat on their value, as illus-

trated in our own Society. ive

1. In the first place it furnishes a common bond between per-

sons of various employments and nationalities—whether experts or

not—who are working for a better understanding of nature. The

very diversity of the interests of these special students makes this

bond all the more necessary.

2. It furnishes a means for mutual stimulation and inter-

change of ideas, whereby the amateur gets the advantage of the

view point of the specialist, and the professional may keep the spirit

of the amateur.

3. Not only are knowledge and investigation specialized in an

extreme fashion, but the specialization, in the processes necessary

to bring work to its completion and to develop it from all needed

aspects, is so detailed that the draftsman, the photographer, the

maker of instruments of precision, the technician, as well as the

biologist, must appear in every piece of good work.

4. There ought also to be something in such a union of inter-

ested people, scattered as we are over the whole land, when it comes

to coordinating results of similar work from different localities.

This is peculiarly true of such studies as vary with locality—as,

diseases, plankton, systematic biology, and the like.

5. The proposed resumes and summaries, with suitable but

not too elaborate bibliographies, ought to be of very great aid to

the rank and file of a general society; and if this Society can fur-

nish such a general review of the important fields of biology it will

be a real contribution to the needs of the student.

For these and various other reasons it appears to me that study

with the microscope furnishes the most interesting side interest, or

68 NOTES, REVIEWS, ETC.

hobby. It is attractive in itself and allies the student at once with

many departments of natural science. It is impossible to get out of

range of interesting things to be examined, and while different

workers will undoubtedly get returns proportional to their interest

and insight, ample returns can be had by all.

V. A. Latuam, M. D.

SOME OF THE NEEDS OF THE SOCIETY AS SEEN BY ONE OF THE

OLDER MEMBERS

In the light of the fact that specialization is on the increase, one

of the problems of the society at present is in bringing together and

holding together the older and the newer members. The newer

members are apparently less interested in the perfecting of methods,

and more in the resulting knowledge of biology. The older mem-

bers possibly like to dwell more on the instrument and on the

beauties and adjustments found in it, and on its possibilities as an

instrument of precision. We need to see that these interests are by

no means antithetical, but rather supplementary. Many modern

workers no not use their instruments and their technic to the point

of refinement practiced by earlier workers; nor get the full value

out of the modern improvements in the microscope and its ac-

cessories.

We need also to see that the Society meets the needs of both

the beginner and the man of research. If it is worth while to have

a general society containing amateur workers, it is worth while

to take such steps as will make the society helpful to the inde-

pendent worker with the microscope, even when he is making his

start. In many instances the back volumes of the Society will con-

tain much that is valuable to the beginner. Can’t we have a series of

notes, or a comprehensive article, on “How the New Worker May

Independently Take up the Work With the Microscope?” Would

not such a discussion, coupled with a brief department of notes and

suggestions of a practical nature, help keep alive the amateur and

independent worker who has not the opportunity of personal asso-

ciation with other workers?

V. A. Latuam, M. D.

AMERICAN MICROSCOPICAL SOCIETY 69

MICROMETRIC MEASUREMENTS

In the Journal of the Royal Microscopical Society for Oct.,

1910, is a scholarly paper by Dr. Marshall D. Ewell, twice President

of this Society, on “Comparative Micrometric Measurements.” The

paper is too technical to report in brief, but the writer’s conclusions

are:

1. That measurements of micrometric spaces, from .oI mm. to

0.I mm., when made in large series by experienced observers, may

be trusted as accurate within limits quite appreciably less than 0.1 yu.

2. That it is best to use the lowest power that will properly

resolve the object; and that greater magnification for purposes of

more accurate measurement is illusory.

THE CENTROSOME IN LIVING PROTOPLASM

The studies of living protoplasm are continually becoming more

numerous and successful. The centrosome, for example, has been

seen in living cells as follows: Of the mucous membrane from the

stomach of the frog, the cat, the dog, and the horse; of the pos-

terior corneal epithelium of the cat; in the summer ova of the tur-

bellarian Mesostoma; in the early cleavage cells of the embryo

of the nematode Ascaris; and in the eggs of certain species of

sea-urchins,

LIFE CYCLE IN AN AMEBA

Professor Maynard M. Metcalf, Journal Exp. Zool., Oct. 1910,

describes some interesting conditions believed by him to be stages in

the life-cycle of an Ameba. Upon the body of active Amebae were

formed numerous protuberances or “gemmules.’”’ These gem-

mules finally became free, and are believed, after a period of inac-

tivity, to give rise to small bi-flagellate monads containing a part of

the original nuclear matter. These may withdraw their flagella, be-

come ameboid, and occasionally divide by binary fission. Instances

of copulation, and of permanent fusion, of these flagellospores in

pairs were observed. The result was a typical small crawling ameba

(of the blattae type).

DIATOMS AS A FOOD SUPPLY FOR ORGANISMS

Systematic study of plankton, and experiments in rearing ame-

bae and larvae of different kinds, are all increasing our appreciation

70 NOTES, REVIEWS, ETC.

of the role of Diatoms as the nutritive foundation of the various

successions of life and activity among the micro-organisms.

In a careful and quantitative study of the plankton at the south

end of the Isle of Man, it has been found that the Diatoms are

foundational to the most rapid annual increase in life, which takes

place in the Spring. Dinoflagellates furnish a well-marked, but

less pronounced, maximum later, between April and August. Cope-

pods have a maximum in early summer, usually later than that of

the Dinoflagellates.

E. J. Allen and E. W. Nelson find that Diatoms are peculiarly

satisfactory food in the artificial rearing of various marine larvae

(sea-urchins, worms, mollusks). Several American students have

found that most cultures in which Diatoms succeed prove prolific of

Ameba.

A PECULIAR ACHLYA

W. C. Coker in Botanical Gazette for Nov. 1910, describes a

new species of Achyla from North Carolina. He calls it A. caro-

liniana. The oogonial hyphae often branch in such a way as to sug-

gest the three balls of the pawn-brokers shop. The oogonial hypha

in about 1-6 of the oogonia protrudes into the oogonium in a way to

suggest the action of an antheridium. These are the distinctive

marks. This genus and other Saprolegniaceae present a most at-

tractive field of study for the amateur as well as the professional

student of aquatic botany. They are easily cultivated, are easily

observed, and respond readily to changes of conditions.

TRANSFORMATION OF SPECIES OF VAUCHERIA

A French investigator has succeeded in producing a transfor-

mation in species of the common alga Vaucheria by varying the con-

ditions of growth. IV. terrestris, which showed as a pure culture

when grown in the air, assumed all the characteristics of V. gemi-

nata when grown in an aqueous nutrient solution. By more vigor-

ous nutrition the experimenter was able to effect a still further

transformation into a form like no known form, in which there

was a tendency for the oogonial branches to assume further vege-

tative divisions and later to develop into both oogonia and anthe-

ridia. In other words, a branch that normally produced female

AMERICAN MICROSCOPICAL SOCIETY 71

structures only, through changed nutrition came to develop both

sexes.

SEXUAL PERIODICITY IN DICTYOTA

An interesting case of periodicity in the release of sexual

cells in Dictyota is reported from Naples by I. F. Lewis in the Bo-

tanical Gazette, 1910. It is similar in some respects to that recorded

on page 14 of this issue for the worm Odontosyllis. Mature gametes

are released 2 or 3 days after the neap tides. The rudiments of the

next generation of gametes begin at the same time. The author

finds that the critical points (formation and liberation of the sex-

ual bodies) are reached on the day that low water occurs at or near-

est mid-day. Thus the maximum intensity of light must be a prin-

cipal factor in these periodic phenomena. At other places where

the plant has been studied this simple correspondence is somewhat

modified. This may be due to the persistence of certain inheritances

of earlier adaptations.

QUINONE FIXATION OF ALGAE

A. Bonnet says that even the most delicate algae—as the Siph-

oneae, Confervaceae, Conjugatae, Florideae, etc., may be satisfac-

torily fixed in freshly prepared quinone solution with a strength

of 4:1000. The advantages of the method are: That it may be used

in either salt or fresh water; and that it resists well the dehydration

necessary for mounting either by the glycerine-jelly or balsam

method. The treatment stains the chloroplyll a greenish brown, and

the non-green protoplasm a light yellow.

GROWTH OF NERVES IN CULTURE MEDIA

Professor Ross Granville Harrison (Jour. Exp. Zool., Dec.,

1910) has succeeded in growing excised embryonic cells from the

nervous system of tadpoles, in hanging-drop cultures of coagulated

lymph. Nerve fibrils of more than 1 mm. were thus secured which

could be observed at all stages of growth from the nerve cells.

His observations show (1) that the primitive nerve fibers are

formed by actual protoplasmic movement of the hyaline ectoplasm

of the nerve-cell in a way quite analogous to the extension of pseu-

dopodia in rhizopods, and that thesé fibers end in a rhizopod-like en-

largement with fine processes or pseudopodia; and (2) that the

72 NOTES, REVIEWS, ETC.

neuro-fibrillae differentiate later within this filament. This dem-

onstration is believed to deny the necessity of supposing with Hen-

sen and Schultze and others, that formed structures outside the

original nerve cell are largely responsible for the structure and

course of the nerve fibers.

CAUSES OF CONJUGATION IN PARAMECIUM

Professor Jennings has recently added to his interesting studies

of the Protozoa a study of the conditions determining conjugation

in Paramecium. He finds that successive conjugations may occur

in some cases at intervals of five days and in others of two weeks

to a month. In one case conjugation was repeated after only four

divisions. In others, divisions were followed for three years with

no signs of degeneration and without any conjugation whatever.

The conditions that induce conjugation are both internal and exter-

nal: Internal (inherited), because different stock subjected to

exactly similar conditions had vastly varied periods; external, be-

cause certain nutritive cycles affect the rate. Starved individuals

do not conjugate. Individuals that have been starved and are be-

coming well-fed do not conjugate. Thriving individuals with de-

clining nutritive conditions tend to conjugate. The author is dis-

posed to believe that senile degeneration due to a long series of

divisions which has been thought to be the principal cause of con-

jugation does not figure as a factor of moment.

POWERS OF RESISTANCE IN PIOPHILA LARVAF

It has been shown that Piophila larvae, which are to be found

in cheese and are favored by some eaters of cheese, can pass thru

the gut of the dog or of man without being injured. It is claimed

that they do some damage to the wall of the intestine by the action

of their oral hooks and ventral papillae. They are very hardy and

resist the action of alcohol and other killing agents for considerable

periods of time.

THE BACILLUS OF TYPHUS

W. Predtjetschensky, in Centralblatt f. Bakteriol. u. Parasit.

1910, believes that he has discovered the specific Bacillus of typhus

fever. His evidences are: The bacilli are found abundantly in

blood of patients suffering from the fever, especially about the 6-9

AMERICAN MICROSCOPICAL SOCIETY FS

day; they are not found in other nearby patients, suffering from

other diseases but not having typhus; they show the agglutination

phenomena known in typhoid.

NEMATODE IN THE MUSCLES OF THE EARTHWORM

B. Buchanan, in Proceedings of Royal Society of Victoria Aug.

1910, describes a parasite (probably nematode) with an interesting

habitat. It was found imbedded in the circular muscle layer of an

earthworm. It has the general appearance of a nematode, but

lacks entirely the reproductive bodies. The author suggests that it

may be the larval stage.

A DEVICE FOR TRANSFERRING SPECIMENS

A simple method of transferring specimens while dehydrating

and clearing was devised by a student a few years ago and has

proven very convenient for general work.

An aluminum thimble such as can be obtained for five or ten

cents is perforated by many pin-holes and a bail of thread is at-

tached at the top. The specimens are placed in the basket thus

formed and lifted from one solution to another without handling.

The thread bail is long enough to hang over the top of the bottle

containing the solution and so support the thimble at the surface of

the liquid to prevent light specimens from floating out. The

stopper can be returned to hold the thimble in position as well as to

cover the bottle.

Eipa R. WALKER.

CHARTS TO SUIT THE COURSE

It may not be generally known to biologists how easily and

cheaply very presentable charts may be made, right in the labora-

tory. White or cream-colored curtain cloth (Holland) of any

convenient width, say forty inches, may be bought by the roll of

ten yards or more, and may easily be cut into proper lengths and

tacked onto one inch half-round moulding. The moulding may be

bought, cut into proper lengths, say forty-two inches, of any planing

mill, and may be painted and varnished in a very short time. It is

best not to attach the cloth to the moulding until after the figures are

drawn.

74 NOTES, REVIEWS, ETC.

The figures should first be outlined lightly in pencil or in white

chalk, and then be finished with India ink and water colors of the

desired shades.

Any student assistant can, with care, make very creditable

charts, or they may be obtained by having each student in a technic

course make a chart, or a part of one, as a part of the work of the -

course.

Diagrams and figures representing sections are very easily

drawn; surface views and dissections require more artistic skill.

The ink and the water colors can be applied without difficulty

with ordinary camel’s hair brushes.

The chief advantage in making these charts is that the exact

series of figures desired for any particular course may be copied

from well known sources.

A. M. REESE.

It is a pleasure to announce that Mr. Ernst Leitz of Wetzlar,

Germany, has been awarded the degree of Doctor of Philosophy by

the University of Marburg in recognition of his distinguished

services to science thru the making of optical instruments during the

last half century.

Major E. V. Elwes, in the Journal of Marine Biological Asso-

ciation of the United Kingdom for 1910, furnishes some very valu-

able analytic keys to the genera of littoral polychetes from the

shores of the English Channel.

THE BUILD OF A MICROSCOPE

A comparison between the Microscopes of say 20 years ago

and of the present day discloses many modifications in construc-

tion and design. In place of the former tall instrument in bright

brass frequently with considerable more vibration than could be

tolerated nowadays, we have the compact, sombre-looking models

with which present day workers are familiar.

In a microscope stand, rigidity and freedom from spring when

the various parts are brought into working are extremely desirable,

but are very difficult to attain with high power oil immersion objec-

tives. Much of this spring is observable when pressure is put on

the stage to move the object in the field. A step in the right direc-

AMERICAN MICROSCOPICAL SOCIETY 75

tion has been made in the general construction of microscopes by

abandoning the many separate parts in favour of large portions cast

in one piece of metal. This method is one which the firm of W,

Watson & Sons Limited, 313, High Holborn, London, W. C., have

pursued with conspicuous success for several years past. There

must necessarily be separate parts, but this firm has shown a way

in which, by interlocking, those parts which must be joined together

may be made equal to solid metal, and the arrangement which has

been so much appreciated by users of their Van Heurck

microscopes has now been madeuse of in theirimproved

model of the Royal Microscope.

We append two illustrations showing the way in

which this is effected.

Fig. 2. Breet

Fig. 1 shows the back end of the stage where it is attached to

the limb. It will be noticed that rising from the surface are two

cheeks which fit on either side of the limb and are secured to it by

3 screws on each side, and the bolt for the inclining joint passes

through the centre of the whole. Obviously a stage attached in this

manner must be vastly stronger than one that is merely dependant

on attaching screws for retaining it in its position, and a practical

use of a stage built under these conditions soon discloses its. won-

derful rigidity.

In pursuance of the scheme already utilized, it will be noticed

that the limb is continued below the stage in one piece, and to the

face of it is attached, beneath the stage a substage with its coarse

70 NOTES, REVIEWS, ETC.

and fine adjustments. This is shown in Fig. 2 and the letters refer

to the following parts:

The Limb.

1. The Limb continued downwards to carry Substage.

The bolt hole for the inclining joint.

Substage condenser carrier.

The same fitting swung out of the optical axis.

Fine adjustment milled head.

Coarse adjustment milled head.

Tail-piece carrying the mirror.

The matter is one which is of considerable interest to micro-

scopists, especially those who are interested in high power work

with the best means available, and it is an indication of the way

in which the building of the most accurate of all instruments may

be solidified and improved.

OAD S >

THE LEITZ DOUBLE DEMONSTRATION EYEPIECE WITH POINTER

This eyepiece is an important addition to the many practical,

auxiliary apparatus intended to facilitate microscopical teaching,

thus saving time.

THIS DOUBLE DEMONSTRATION EYEPIECE, with pointer, is an

instrument the need of which was seriously felt for a long time.

It has been constructed with a special view to help the teacher in

demonstrating a particular object in the visual field of a Microscope.

It is used like any ordinary Eyepiece, by simply placing it into

the draw tube of a Microscope. Jt enables two observers to view,

simultaneously, the image which is produced and by means of the

pointer they may demonstrate mutually any part of the image.

The pointer is universally adjustable by a ball joint and can

be moved forward or backward, thus the whole field can be easily

covered.

The construction of the Apparatus may be easily understood

from the accompanying illustration:

AMERICAN MICROSCOPICAL SOCIETY ING

Patented D. R. G. M. 435297

Between the lenses of the vertical ocular, just above the eye-

piece diaphragn, is placed the double prism I and II, through which

the greater part of the light passes in a straight line. The remainder

of the light being deflected on the long side of prism I into another

prism, No. III in illustration, which again directs the path of rays

into the auxiliary (side) eyepiece which is of terrestrial construc-

tion. This side eyepiece is of sufficient distance (7 inches) from the

vertical one so that the two observers will not interfere with each

other.

The focusing is chiefly done by the person observing through

the vertical ocular, it being more convenient; at the same time the

focusing of the image is performed, automatically, in the side eye-

piece.

The eyepieces have, in both tubes, an initial magnification of

approximately 3144 +. Both images are sharply defined, colorless

and free from distortion. The student will use the vertical eyepiece,

this giving him the proper position in viewing a Microscopical

image, while the demonstrator, being familiar with the object under

observation, will use the auxiliary (side) eyepiece.

This new LEITZ DOUBLE DEMONSTRATION EYEPIECE with pointer

will be of immense help to the teacher as well as to the student.

A trial will easily confirm this, and every institution sooner or

later will have one or more of these practical auxiliary apparatus.

WILLIAM HENRY SEAMAN, LL.B., M.D.

bo acs tue ave AL Sea vice eat

NECROLOGY

WILLIAM HENRY SEAMAN, LL.B., M.D.

Dr. Seaman died, June 11, 1910, in the 73rd year of his age,

and after a life of most varied and effective activity in scientific

pursuits.

He has been an active member of this Society since 1886, and

was its efficient Secretary from 1890 to 1895.

He was born November 1, 1837, in New York City, at the

family residence in Broome Street, the son and only child of John

G. and Ann R. (Wall) Seaman, both of them of the Society of

Friends.

On his father’s side he descended from Captain John Seaman,

who received a patent of a large tract of land at Hempstead, L. L,,

about the year 1650. From him most of the Seaman family in

America are descended. Dr. Seaman’s mother was a native of

Crosswicks, New Jersey, and was educated at Bethlehem, Penn-

sylvania.

Until eleven years old, Dr. Seaman was educated by his mother.

Afterward he attended a Friend’s School in Hester Street, New

York City, and assisted the principal of the school in preparing

experiments in physics and chemistry, to illustrate the lectures.

When fifteen years old (in 1852) the family removed to Plain-

field, New Jersey, and afterwards to Woodbury, New Jersey, where

they remained until 1869, when Dr. Seaman came to Washington.

For ten years, 1869-79, Dr. Seaman was employed in the De-

partment of Agriculture. In 1879 he was appointed an Assistant

Examiner in the U. S. Patent Office; was promoted from time to

time, finally to be principal Examiner. He held this position at

the time of his death.

Shortly after coming to Washington he attended law lectures

at the Columbian College Law School and in 1872 was graduated

with the degree of LL. B.: the same year he was admitted to the

bar of the District of Columbia.

So WILLIAM HENRY SEAMAN

June 27, 1871, he was appointed Lecturer in Botany in the

Medical Department of Howard University. His connection with

the Department continued until four days before his death, when

he resigned.

Dr. Seaman was appointed September 21, 1874, Professor of

Chemistry in the Medical Department of Howard University and

held this chair until he resigned. The title of the chair covered in-

organic and organic Chemistry and toxicology, and included both

didactic and laboratory work. In addition to this he also from time

to time gave practical lectures on the microscope. When the Den-

tal College was inaugurated in 1881, he became Professor also of

Chemistry therein; and when the Pharmaceutical College was re-

organized (1880-1) he became Professor of Chemistry in that Col-

lege also. May 15, 1897, he was also made Lecturer on Botany in

the Pharmaceutical College. These many duties occupied the major

part of his evenings and he doubtless gave more of his time to the

Medical School than any other member of the Faculty.

Dr. Seaman was ever ready and willing to assist the students

and gave freely of his time and information for their advantage.

It was the same with Faculty matters; his time and his “all round”

acquirements were always at the service of the Medical Depart-

ment. His knowledge of law and science and his general knowledge

and clear judgment were repeatedly called upon and were always of

value.

In 1883 the Honorary degree of M.D. was conferred upon him

by Howard University.

Three times, namely, in aR. 1900, 1910, he was appointed a

delegate from the Medical School to the Convention for the Revis-

sion of the Pharmacopoea.

In 1873 he married Miss Marianna Perkins Clark, of London-

derry, N. H., who survives him. There are no children.

Dr. Seaman contributed many articles to scientific and literary

magazines.

He was a member of many scientific societies, and spoke with

fluency both French and German, the latter being a language in

which much of his work was done. He was member and Fellow

of the American Association for the Advancement of Science; cor-

responding member of The Maryland Academy of Science; mem-

WILLIAM HENRY SEAMAN SI

ber of the Biological Society of Washington; member of the Na-

tional Geographic Society; charter member, and in 1894 President

of the Chemical Society of Washington; member of the American

Chemical Society; for a number of years Abstractor of Chemical

Patents for its journal; member and sometime President of the

Washington Microscopical Society; member and sometime Secre-

tary of the American Microscopical Society and during this service,

editor of its journal. He was a charter member of the University

Club of Washington; an early member of the Cosmos Club, of the

Washington Society of the Fine Arts, and of the American Library

Association, and an active member of the Playgrounds Association

of Washington.

By birth a member of the Society of Friends, after his mar-

riage he was a constant attendant of the First Congregational

Church, a member of its Society and also of the Congregational

Club of Washington.

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TRANSACTIONS

OF THE

American Microscopical

Society

ORGANIZED 1878 INCORPORATED I&Q1

PUBLISHED QUARTERLY

BY THE SOCIETY

EDITED BY THE SECRETARY

VOLUME XXX

NuMBER Two

(DousBLe)

DecatTup, ILL.

Review Printinc & STATIONERY Co.

1911

NOTICE TO MEMBERS

Members of the American Microscopical Society are under

peculiar obligation this quarter to two of our members: to Dr. J. S.

Foote, who, beside furnishing the remarkable series of drawings

in his article, has donated to the Society $150 toward the publica-

tion of this number; and to Mr. Edward Pennock for securing

the adherence of eleven new members to the Society.

Application for entry as second-class matter at the post office at Decatur, Illinois, pending.

OFFICERS.

Pee sdent AAC Eo TLERTZLER, MDS. onc) as alo aa tatees aie aa ahaa Kansas City, Mo.

Vaceseressdents) SMe J LROD. .s sec de acy uaie oi Mote daiaraa fe dl pela Missoula, Mont.

SCKEtar ys) OLIN! GALE OWA Vis U1 4 sche ater erte rela an eictena) sete raveletetticns Decatur, III.

UeEGSUTET 3) ee Te (ELANIKINSONye oie cee oo eel sir ane ince ehaetetalers Charleston, Ill.

GuSTORIEi en NUAGNUS ) PELAUIM co cere le ea ee a area lata teveoey erie Meadville, Pa.

ELECTIVE MEMBERS OF THE EXECUTIVE COMMITTEE

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SL ADSM pe Rees ATA Snap ear adr Mi Ke PS Sarl ui ay ARN A Aran an Nas a Buffalo, N. Y.

EX-OFFICIO MEMBERS OF THE EXECUTIVE COMMITTEE

Past Presidents still retaining membership in the Society

R. H. Warp, M.D., F.R.M.S., of Troy, N. Y.,

at Indianapolis, Ind., 1878, and at Buffalo, N. Y., 1879.

J. D. Hyatt, of New Rochelle, N. Y.,

at Columbus, Ohio, 1881.

ALBert McCaita, Ph.D., of Chicago, III.

at Chicago, IIl., 1883.

T. J. Burrmz, Ph.D., of Urbana, IIl,

at Chautauqua, N. Y., 1886, and at Buffalo, N. Y., 1904.

Gro. E. Fett, M.D., F.R.M.S., of Buffalo, N. Y.,

at Detroit, Mich., 1890.

MarsHALL D. Ewett, M.D., of Chicago, III,

at Rochester, N. Y., 1892, and at Boston, Mass., 1907.

Simon Henry Gace, B.S., of Ithaca, N. Y.,

at Ithaca, N. Y., 1895 and 1906.

A. CuirrForp Mercer, M.D., F.R.M.S., of Syracuse, N. Y.,

\ at Pittsburg, Pa., 1896.

A. M. Buette, M.D., of Columbus, Ohio,

at New York City, 1900.

C. H. E1iceEnmMann, Ph.D., of Bloomington, Ind.,

at Denver, Colo., 1901.

Cuartes E. Bessty, LL.D., of Lincoln, Neb.,

at Pittsburg, Pa., 1902.

E. A. Birce, LL.D., of Madison, Wis.,

at Winona Lake, Ind., 1903.

Henry B. Warp, A.M., Ph.D., of Urbana, III.

at Sandusky, Ohio, 1905.

HERBERT Oszorn, M.S., of Columbus, Ohio,

at Minneapolis, Minn. 1910

The Society does not hold itself responsible for the opinions expressed

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TABLE OF CONTENTS

FOR VOLUME XXX, Number 2

The Comparative Histology of Femoral Bones, with Plates A and I to

EXC DIG. LONE OObES MIO DDSI, toe cn a sie oeitrrie See piacere ene 87

Note on a Growth of Synura in Lake Cochituate, Mass., by Horatio

IN fl Bch 3 FS ci teen a i v9 Ned ED RR LES ere Sree ee NG 141

Recent Progress in Some Lines of Cytology, by Michael F. Guyer....... 145

Notes, Reviews, Etc. Mesostomum ehrenbergii (illustrated) ; Cellular

Activities Connected with Shedding of Leaves; The Herbaceous

Arrangement of Elements Derived from that of the Woody Type;

The Growth of Somatic Cells without the Body; Origin of the Ele-

ments of the Sympathetic System; Regeneration and Cell-division;

Red Blood Cells; To Demonstrate Spirochaeta Pallida; The Study

of Rotifers; A Paper Ribbon-Carrier (illustrated) ; Safety-razor

Microtome /Bladesiie rive teio eee ae ee oie deka s a eee a ete 191

INecrologys) Brederick W. Kuhne, with’ Portrait2-- os2-k occ nee eres 199

Minutesmor-the\ rAnnual e Meeting). sane ciine ian eee een Oe C OR Oree 201

Proposed Disposition of the Spencer-Tolles Fund...................2.- 204

PAG VETTISEMIIETIES acs heck ovale hol atette Sie tche state eee aS eee eotereR meine eee {-VIII

NOTICE

The Secretary is pleased to announce to the Society that more new

members have come into the Society during four months since the issue of

Vol. 29, No. 2, than in any twelve months since 1891.

The officers purpose making this the most notable year’s growth in the

history of the American Microscopical Society. This can be done with

the help of the minority of the membership now actively helping the Secre-

tary, but the result cannot be so satisfactory as if the whole body of mem-

bers were to assist.

There is no desire to make this a large, unwieldy body; but it can easily

be made large enough to sustain a creditable quarterly journal. May we not

confidently expect that each member will give his personal influence to

secure this end?

TRANSACTIONS

American Microscopical Society

(Published in Quarterly Installments)

Vol. XXX APRIL 1911 No. 2

THE COMPARATIVE HISTOLOGY OF FEMORAL

BONES.

By J. S. Foote, M. D.

It is interesting to notice the diversity of structure present in the

femurs of various animals. We have been led to think that bone

is bone; that long bones, and especially similar bones wherever they

occurr, have the same structure because they are used for the

same purposes. This is not true. Microscopical examinations of

entire sections of femurs of forty-three different animals show that

the structures and their arrangements are not at all the same.

They vary in different animals and even in the walls of a bone of

any one animal. The anterior wall is unlike the posterior, the

outer wall unlike the inner. Nor are the lineal portions of a bone

the same. If a long bone, like the femur, is divided into thirds, each

third is found to differ from another third. Therefore, a correct

knowledge of the histology of bone cannot be obtained from pre-

pared sections of small pieces sawed from the walls of bones. Entire

cross sections must be made in each case. Furthermore, a drawing

and description of one long bone will not answer for another.

In a general way femurs answer a common purpose, but in

specific ways they differ considerably. The various habits of

animals, the complex muscular stresses to which their femurs are

exposed and the variations in position relative to the bodies which

they support demand corresponding structural arrangements peculiar

to the animals possessing them. Thus the femurs of swimmers,

flyers, scratchers, climbers, crawlers, runners and jumpers differ

from each other very decidedly. Bone exhibits a very ready struc-

tural response to functional demands.

88 J. S. FOOTE, M. D.

We are accustomed to one type of bone, viz: the Haversian

system type. It is the familiar type described and plated in books.

It is human and will not answer as a formula of the general bone

structure of animals. In most cases a small piece of a long human

bone is described. In some instances entire cross sections of small

bones, as the fibula, radius, metatarsal or metacarpal, are given.

This type, in its pure form, appears to be peculiar to man, as none of

the other femurs examined show it. The completely developed

Haversian system evidently belongs to the higher animals.

Entire cross sections of the femurs of the following forty-

three animals have been examined as they were received. They

were not selected:

LIST OF BONES EXAMINED

AMPHIBIA. MAMMALIA

F i _ Pl A; figs. Marsupials

eres 2. a Opossum, Pl. IV; fig. 22

Placentals

REPTILIA.

Order Rodentia

Alligator, Pl. I, fig. 4 Musk Rat, Pl. IV; fig. 24.

Rat PIs Ve fess:

Rabbit, Pl. IV; fig. 26.

Squirrel, Pl. IX; fig. 50.

Woodchuck, Pl. V; fig. 27.

Prairie Dog, Pl. V; fig. 28.

Snapping Turtle, Pl. gi figs. 5, 6.

AVES.

Order Steganopodes

Pelican, Pl. I, fig. 7.

Order Anseres

Mallard Duck, Pl. II; fig. 8.

Wild Goose, Pl. II; fig. 9.

Order Striges

Owl, Pl. II, fig. to.

Order Accipitres

Eagle, Pl. IT; fig. 11.

Hawk, PI. II; fig. 12.

Order Gallinae

Grouse, Pl. II; fig. 13.

Chicken, Pl. III; fig. 14.

Prairie Chicken, Pl. II]; fig. 15.

Domestic Turkey, Pl. III; fig. 16.

Wild Turkey, PI. III; fig. 17.

Peahen, Pl. III; fig. 18.

Order Picariae

Yellow Hammer, PI. III; fig. 10.

' Order Passeres

Crow, Pl. IV; fig. 20.

Yay, PLATV 3 fig.-21:

Order Carnivora

Skunk, Pl. V; fig. 20.

Raccoon, Pl. V; fig. 30, 32.

Mink, Pl. V; fig. 31.

Weasel, Pl. VI; fig. 33.

Wild Cat, Pl. VI; fig. 34.

Gat Pr Vis ig. s5:

Gray Fox, Pl. VI; fig. 36.

Wolf, Pl. VI; fig. 37.

Dog, PI. VI; fig. 38.

Order Ungulata

Elk, Pl. VII; fig. 30.

Deer, Pl. VII; fig. 40.

Ox, PEO Ville he 43!

Sheep, Pl. VIII; fig. 44.

Goat, Pl. IX; fig. 51.

Horse, Pl. VIII; fig. 41.

Pig, Pl. VIII; fig. 42.

Order Primates

Monkey, Pl. IX; fig. 52.

Man, Pl. IX; fig. 53.

HISTOLOGY OF FEMORAL BONES 89

All sections are taken from the middle of the femurs, ground to

proper thinness, mounted in hard balsam and examined with the

same objectives, oculars and tube lengths of a Zeiss microscope.

Drawings are then made. As some of the femurs are very large and

some are very small, all drawings are made from the viewpoint of

clearness rather than from actual sizes.

The drawings do not make any effort, therefore, to give the

exact number of Haversian systems, laminae, lamellae, etc. The

aim has been merely to show the relative positions, arrangements,

proportions and developments of these structures. The horizontal

line in connection with each femur gives the natural diameter of

the bone.

The following general outline is followed in all examinations:

(1) antero-posterior diameter of the bone; (2) lateral diameter of

the bone; (3) antero-posterior diameter of the medullary canal;

(4) latera ldiameter of the medullary canal; (5) medullary canal,

full or empty; (6) trabeculae of bone, present or absent; (7) can-

cellous bone, present or absent; (8) compact bone; (9) hardness

or density; (10) character of external and internal circumferential

lamellae; (11) arrangement, development and character of the

Haversian systems; (12) laminae—concentric or oblique, position

of; (13) lacunae, character of; (14) canaliculi, character of ; (15)

type of structure.

DETAILED DISCUSSION.

Femurs of the Bull Frog.

The femurs of four frogs are examined, the first unusually

large, the second of medium size and the third and fourth small.

The first femur is 3.5 mm. x 4.5 mm., the second 2.5 mm. x 3 mm.,

the third and fourth 1 x 1.3 mm.

They show different developments of the same type of bone

GPILA, Bigs, 1, 2,.3))'Ph Pigs; 1-3),

Femur of the First Frog.

Pl. A, Fig. 1.

Antero-posterior diameter of bone, 3.5 mm.; lateral, 4.5 mm.

Antero-posterior diameter of medullary canal, 1 mm.; lateral,

2 mm.

The medullary canal is full. There are no trabecule and no

cancellous bone. The bone is soft.

90 ‘J. S. FOOTE, M. D.

Structure. The bone shows three general divisions, viz: (1)

external circumferential lamellae; (2) a central ring of radiating

canals; (3) internal circumferential lamellae. The external circum-

ferential lamellae, three or four in number, surround the bone. Their

lacunae are round and oval, their canaliculi are short and bushy and

all are poorly developed. The central ring, situated between the

external and internal circumferential lamellae, consists of con-

centric lamellae, interrupted by forty-two large radiating canals.

The lamellae are indistinct, their lacunae are round and oval and the

canaliculi communicate with the radiating canals. In some places

the canals, with their canaliculi and lacunae, present an appearance

similar to stems with fine branches and small leaves.

The canals are just visible to the naked eye, or about 0.25 mm.

in diameter. Some of them extend from the internal to the external

circumferential lamellae, some about two-thirds of that distance and

some are interrupted at various points along their way. The central

ring forms about four-fifths of the thickness of the bone, is thicker

in the posterior half than in the anterior, and presents a low de-

velopment.

The internal circumferential lamellae, three or four in number,

surround the medullary canal. They are clearer than those of the

external lamellae, their lacunae are oval and their canaliculi are

short and bushy. In the posterior wall, situated partly in the lamellar

and partly in the central ring, is a large vascular canal on its way to

the medullary canal. The internal lamellae are poorly developed.

The type of bone is lamellar, poorly developed.

The peculiar features are the radiating canals and the associ-

ation of poorly developed lamellae and lacunae with them. The

bone is an early form of lamellar development.

Femur of the Second Frog.

PIP Aisne:

Antero-posterior diameter of bone, 2.5 mm.; lateral, 3 mm.

Antero-posterior diameter of medullary canal, 1.5 mm.; lateral,

1.5 mm.

The medullary canal is full. There are no trabecule and no

cancellous bone. The bone is soft.

HISTOLOGY OF FEMORAL BONES gI

Structure. Around the bone is a very narrow ring of dense

lamellae containing a few long, narrow lacunae and long canaliculi.

In the center of the anterior wall is a notch, which extends

inward about half of the width of the wall. The notch is a part of

the nutrient canal. Beginning a little to the outer side of the

posterior mid line and extending around the outer wall, anterior

wall, and about one-fourth of the inner wall, the entire thickness of

the bone is composed of 16-18 concentric lamellae with oval lacunae

and bushy canaliculi. The remaining portion of the bone consists of

concentric lamellae in which are cross sections of 36-38 canals ar-

ranged radially in twos and threes. The canals are surrounded by

clear areas and extending from them in all directions are very fine

canaliculi. In the anterior inner wall the canals assume a longi-

tudinal direction. The type is lamellar.

Its peculiar feature is a development intermediate between that

shown in the first and third frogs.

Femur of the Third and Fourth Frogs.

PivAL iene oP i vingsa

Antero-posterior diameter of the bone, 1 mm.; lateral, 1.3 mm.

Antero-posterior diameter of the medullary canal, 0.5.; lateral,

0.6 mm.

The medullary canal is full. There are no trabecule and no

cancellous bone. The bone is soft.

Structure. The section is composed of eight or nine lamellae,

concentrically arranged around the medullary canal. There are no

divisions into external circumferential lamellae. There are no radi-

ating canals. The lamellae are clear, their lacunae oval, long and

narrow and their canaliculi are long and numerous. The type is

lamellar.

The peculiar feature is its completeness as compared with pre-

ceding figures.

These figures show drawings of femurs taken from the same

species of frogs, but of different sizes and weights. The largest,

Fig. 1, is lowest in development ; the second in size, Fig. 2, is next,

and the third, Fig. 3, is last and most complete. They are all of the

g2 Jie/Se, HOODE, UMD:

lamellar type, though of different developments. In Fig. 1, the radi-

ating canals, with poorly developed intervening lamellae, indicate a

low stage of development. In Fig. 2 half of the canals have disap-

peared and better developed lamellae are formed. In Fig. 3 all of

the canals have disappeared and the whole bone consists of con-

centric lamellae.

Fractured and Repaired Femur of the Frog.

Pl] oFag: 2, 3:

One of the femurs (Fig. 2) had been fractured about the

middle of the shaft and repaired. The ends of the bone had slipped

by each other and new bone had formed around the fragments. In

the section, which was taken from the middle of the new bone, two

cuts of the femur appear situated eccentrically. The upper frag-

ment, proximal, shows cell growths bursting through the wall of the

bone (Pl. I, Fig. 2, A. B.). In the lower fragment, distal, no cell

outbursts appear.

Around the two fragments and extending between them is a

formation of cancellous bone which is the new bone of repair.

The cancellous bone resembles large Haversian systems, although

there are no Haversian systems in the femur. This fact suggests

a genetic relationship between cancellous bone and Haversian

systems, and also indicates that bone repairs are made by cancellous

bone. Evidently the lamellar type is the simplest type of bone struc-

ture.

Femur of the Alligator.

PL EoPig'4:

Antero-posterior diameter of the bone, 15 mm.; lateral, 17 mm.

Antero-posterior diameter of medullary canal, 5.5 mm.; lateral,

6 mm.

The medullary canal is full. No trabecule. Very little can-

cellous bone. The bone is hard.

Structure. A thin cross section of this femur held up to the

light presents a ringed appearance like that of a cross section of the

trunk of a tree.

PLATE A

Anterior wall

External

Civcumferential Co

arnellae (

Radiating

Canals

Innerwall ap

Inteenal

circ.lamellae Ss

tenure afa large Frog Showen

lamellae interrupted by radiating

Canals. Low lype of structure.

Notch of _

nuteient arte vy

Anlevioe

Inner wal

Fi By wei

Femur of Frog, Showing

fomieligh ereveluer.

HISTOLOGY OF FEMORAL BONES 93

Under the microscope the following concentric rings are found,

beginning with the circumference:

1. A wide ring composed of irregularly-shaped canals enclosed

within a network of canaliculi, radiating from long and oval lacunae,

embedded in bone substance. Lamellae do not appear. The ring

has the appearance of very incomplete Haversian systems. The

lacunae are small or large and their canaliculi are long, branching

and bushy.

2. A second narrow, laminar ring composed of two or three

lamellae between which are long narrow lacunae, with long, straight

canaliculi. The lamellae are well developed.

3. A second ring of incomplete Haversian systems, narrower

than the first, but of similar construction.

4. A second narrow lamina, like the first.

5. A third ring of incomplete Haversian systems, like the other

two, excepting that it is a little denser.

6. A third lamina, like the two first described.

7. A fourth wide ring of incomplete Haversian systems like

the others.

8. A fourth narrow ring of internal circumferential lamellae,

three or four in number, interrupted by a little cancellous structure

in the inner and outer walls. It may be noticed that the bone has

four concentric laminae alternating with four rings of incomplete

Haversian systems, which is practically the same structure as found

in the femur of the turtle. The bone is hard.

Its peculiar features are the absence of complete Haversian

systems, its uniform concentric ringed structure, its laminar de-

velopment and the presence of incomplete Haversian systems.

Femur of the Snapping Turtle.

PID igs; 6!

Antero-posterior diameter, 8 mm.; lateral diameter, 8.5 mm.

Antero-posterior diameter of medullary canal, 1 mm.; lateral

diameter, I mm.

Medullary canal is full. No trabecule.

Structure. The walls of the shaft are very thick, proportion-

ately, and the medullary canal is very small. The femur is nearly

94 J. S. FOOTE, M. D.

solid. Around the medullary canal is a zone of cancellous bone.

Around this is a thick zone of compact bone. The bone is hard.

This variation in the relative diameters of the shaft and medullary

canal is in marked contrast with the measurements of other femurs.

The type of structure is mixed and incomplete. The bone presents

quite a complicated arrangement of its structural units, lamellae,

laminae and Haversian systems. The following structures appear,

beginning with the outer boundary and proceeding toward the medul-

lary canal:

1. A clear peripheral lamella of bone containing only a few

irregularly-shaped lacunae, with few canalicull.

2. A complete concentric lamina of bone composed of four or

five lamellae closely united. The lacunae are oval, round or long

and narrow and their canaliculi are numerous and bushy.

3. A wide ring of incomplete Haversian systems. These sys-

tems are composed of oval or round lacunae arranged around rather

large Haversian canals. The canaliculi are radiating in arrange-

ment. The lamellae of the systems are not distinctly marked. The

canals are large. The systems present an appearance of incom-

pleteness.

4. A second concentric lamina composed of three or four

lamellae of bone with long narrow lacunae and bushy canaliculi.

5. A second wide ring of Haversian systems similar in all

respects to the first.

6. A third concentric lamina of three or four lamellae similar

to the others described.

7. A third ring of Haversian systems, narrower than the

others, otherwise similar.

8. A fourth concentric lamina similar to the others described.

9. A wide zone of cancellous bone surrounding the medullary

canal.

Thus the femur has four concentric laminae alternating with

three rings of incomplete Haversian systems. The laminae appear

to be more completely developed than the systems. All of the

laminae and rings of Haversian systems, at one point of the section,

bend inward from the external surface to the cancellous central

bone.

HISTOLOGY OF FEMORAL BONES 95

Femur of the Pelican.

Pil, hips 7

Antero-posterior diameter of the bone, 11.5 mm.; lateral, 12 mm.

Antero-posterior diameter of the medullary canal, 9.5 mm.;

lateral, 10 mm.

The medullary canal is full. There are no trabeculae. The bone

is of medium hardness. No cancellous bone.

Structure. External circumferential lamellae, four to ten in

number, surround the bone, excepting at the anterior and outer

posterior ridges. The lamellae are well developed, their lacunae are

long and narrow and their canaliculi are long and branching. At

the anterior and posterior ridges the lamellae are interrupted by

tendon insertions.

The central ring is composed of Haversian systems in different

stages of development. Underneath the external lamellae is a

narrow ring of well-developed Haversian systems.

The main portion of the bone is composed of oval and round

lacunae, with short, bushy canaliculi, forming a delicate network

within the bone substance. There are no lemellae, laminae or

Haversian systems. Wide branching canals extend from the medul-

lary canal outward and cross the bone in all directions, forming a

coarse network. This portion of the bone resembles reptilian bone

CPlT, Fig. 4,.5, 6).

The posterior wall consists of rather indistinct whorls of lacunae

and their reticular canaliculi bordering on the medullary canal. In

some places half of a system forms the boundary line.. The outlines

of the Haversian systems are more clearly marked in the internal

than in the external half of the wall. The lacunae are long and

narrow. The internal circumferential lamellae, two or three in

number, surround the medullary canal, excepting in the posterior

wall. They form an extremely narrow boundary of the medullary

canal. The lamellae are only partly developed. The lacunae are

oval and the canaliculi are short and bushy.

The section shows a thickening a little to the inner side of the

anterior mid line. The external surface has tendon insertions. ex-

tending through the external circumferential lamellae. The canals

96 J. S. FOOTE, M. D.

of this region have a transverse direction. There is another thick-

ening in the outer wall formed of crude Haversian systems and two

slight thickenings in the posterior wall formed in a like manner.

The type is Haversian system, undeveloped. The peculiar feature

of the bone is its low stage of development.

Femur of the Mallard Duck.

Pl. II, Fig. 8.

Antero-posterior diameter of the bone, 4.6 mm.; lateral, 6.3 mm.

Antero-posterior diameter of medullary canal, 3.5 mm.; lateral,

5.5 mm.

Medullary canal empty. No trabecule and no cancellous bone.

The bone differs from that of the wild goose in that it does not show

the division into outer and inner rings of Haversian systems and

laminz. It is of medium hardness.

Structure. 1. External circumferential lamellae, four to six

in number, with long, narrow lacunae and branching canaliculi.

2. A wide ring of various combinations of irregularly-shaped

Haversian systems and short laminae. No plan of arrangement is

evident. The systems appear to be a laminar formation doubled or

rolled into crude forms. Their lacunae are rather few and their

canaliculi are short and bushy. Their lamellae are clearly marked.

They run ih all directions, as may be seen from their cross sections.

The laminae are short (inter-Haversian), and the canals are numer-

ous and frequently intersecting. Their lacunae are long or oval and

their canaliculi are bushy.

3. Internal circumferential lamellae, three or four in number,

with long lacunae and branching canaliculi. Along the posterior

ridge and surface the Haversian systems are more numerous and

better developed.

The bone is of the mixed type, but incompletely developed.

Femur of the Wild Goose.

|e Ad Bed BY 0

Antero-posterior diameter of the bone, 9 mm.; lateral, 8.5 mm.

Antero-posterior diameter of medullary canal, 7 mm.; lateral,

7 mm.

: v

— fi

trom

PLATED

cell growth

bursting through

the wall ofthe

femur at A,B. anterioyY

Lamellae upper fragment wall....

of the femur

Incoinplete

Fig. | Haverslan

Femur of afro Fs >

UA NRG OU Da ee Systems...

type of Structure

Laynina..

Lowey fragment

of the femur,

Lacunoe.

AVL LY

NI F193.

Fig. 2, , Cancetlous bone p<

We Fractured and repaired bralelins NNW!

ae femur of a frog Fig. 4

Femur of an Alligatoy Show tng

Goncentric rings of very Lncomplete

HaverSian Systems and laminae

Circumferential

lamina

c — s ; ,

Cte tens eR Anterior wall

oy MYMNOs. =. aster

Circumferential Haversian ystems, # Yarrow

lamina Haversian Systems. acing of

Incomplete . :

: circumferential |

HaverSian fa ces sees Havevsian Systems

SyStems.. H. Systems..

circumferential €. lamina =~. Network of

Le canaisand

Haversian SyStemss Canatieslt

iedutiayy medullary inner wall

Qiwailecensen

Circuinferential Canal at Nl L

lamina...... Cancellous : incerna

Incomplete ome: eee Sa ; oF ay

aversian Systems. g Wide Canals

Giycumferential

lamina. .°

CancellouS bone...

#5 "9. g Fig. 6

Femur of a Snapping, turtle Showing A portion of fg.¥ enlarged.

alternating Haverslan Systems

Gnd Circumferential Laminae.and

Small medallary Canal.medullary 7

Canal iS very Small. Fig.7

Femur of a Pelican-Showing alow.

Stage of development.

HISTOLOGY OF FEMORAL BONES 97

Medullary canal is full. No trabeculz and no cancellous bone.

The bone is of medium hardness. The medullary canal is large and

the walls of bone are thin.

Structure. The external circumferential lamellae are well de-

veloped and vary from four to ten in number. Their lacunae are

long and narrow and their canaliculi are rather few in number. At

the posterior ridge are found many Haversian systems incompletely

developed. Their lacunae are round or oval and their canaliculi are

few. The anterior wall of the bone is composed of incomplete

Haversian systems occupying the whole thickness of the wall be-

tween the external and internal circumferential lamellae. The re-

mainder of the bone, about four-fifths of the whole, shows quite

different structures and arrangements in the two walls, outer and

inner. The outer wall is composed of irregulariy-shaped laminae

and undeveloped Haversian systems. The laminae are confined to

the inner half of the wall, while the Haversian systems occupy the

outer half, situated under the external circumferential lamellae.

The two halves are well marked and distinct from each other.

The lacunae of the systems and laminae are oval and their canaliculi

are few and short. The Haversian canals of the laminae are irreg-

ular and branching. The inner wall of the shaft is composed of an

internal band of well-developed laminae and an outer band of rather

poorly-developed Haversian systems. The band of Haversian sys-

tems is just under the external circumferential lamellae, the band

of laminae is just outside of the internal circumferential lamellae.

The laminae are better developed than the systems. The peculiar

structural feature of the whole wall of the bone is its division into

two equal concentric rings, one of Haversian systems and the other

of laminae. The internal circumferential lamellae, from three or

four to ten or twelve in number, are well developed. On the left

side of the bone quite large canals extend from the medullary canal

through the laminae to the Haversian canals between the laminae.

The type is mixed.

The bone has the following rings beginning with the outside:

1. External circumferential lamellae.

2. Irregular laminae and Haversian systems.

98 J. S. FOOTE, M. D.

3. Well-developed laminae.

4. Internal circumferential lamellae.

Indistinct arrangements of similar structures are present in the

femurs of several other birds.

Femur of the Large Horned Owl.

Pl, II, Fag: ro.

Antero-posterior diameter of the bone, 8 mm.; lateral, 7.5 mm.

Antero-posterior diameter of medullary canal, 6 mm.; lateral,

6 mm.

Medullary canal is full. No trabecule and no cancellous bone.

The bone is hard, the walls thin.

Structure. 1. The external lamellae vary in number. In some

places there are three, in some six, in other places nine. They are

narrow, their lacunae are long, numerous and have very fine, long

canaliculi. Here and there canals traverse the entire thickness of

them all.

2. A ring of small, irregularly-shaped, incomplete Haversian

systems. They are best developed along the posterior ridge. In the

anterior wall they are few and confined to the region which is just

below the surface. Between the posterior and anterior middle lines

they are rather indistinct, on account of their shape, arrangement

and incomplete formation. The canals are short or long, angular

and branching. They are very prominent and reunite with each

other frequently. Along some of them are lamellae, along others

incomplete Haversian systems. The entire ring impresses one as

a transitional blending of lamellae into Haversian systems. The

lacunae are oval, numerous and have bushy canaliculi.

3. The internal circumferential lamellae differ from others ex-

amined. They form a thick, heavy ring around the medullary canal.

There are thirteen to twenty of them, which, on the outer wall of

the bone, merge into six laminae. The whole ring of the internal

lamellae forms about one-third of the thickness of the wall of the

bone. It is traversed by many canals extending from the medullary

canal into the canals of the Haversian systems. Their lacunae are

long and numerous and their canaliculi are bushy. The bone is of ©

HISTOLOGY OF FEMORAL BONES 99

the Haversian system type undeveloped. The peculiar feature of the

bone is the thick, well-developed internal circumferential lamellae

which merge into laminae.

Femur of the Eagle.

Pl) Ti Figs 19.

Antero-posterior diameter of the bone, 1 3 mm.; lateral, 14 mm.

Antero-posterior diameter of the medullary canal, 11 mm.,

lateral, 11.5 mm.

Medullary canal is empty. Trabecule are present in the lower

third. No cancellous bone. The bone is of medium hardness.

Structure. The external circumferential lamellae, six to ten

in number, surround the bone, excepting at two posterior ridges,

where they are interrupted by tendon attachments. They are fully

developed. Their lacunae are long, narrow and concentrically ar-

ranged and their canaliculi are rather short and branching.

The central ring of bone is composed of six to twelve con-

centric laminae, interrupted here and there by poorly-developed

Haversian systems. The canals which separate the laminae are

relatively wide and, on account of their frequent communications

with neighboring canals, they present the appearance of a coarse

network.

The laminae are mostly short and consist of four to six or

seven lamellae. Their lacunae are oval or round and their canaliculi

are short and bushy. They indicate a low stage of development. A

few poorly-developed Haversian systems are scattered among the

laminae and in some instances appear to be circular dilatations of the

concentric canals.

Internal circumferential lamellae, six to twelve in number, sur-

round the medullary canal. They are fully developed and are fre-

quently crossed by canals extending inward from the medullary

canal. Their lacunae are long and narrow and their canaliculi are

long and branching.

On the posterior surface are two ridges, one central and one on

the posterior inner lateral border. The bone at these points consists

of poorly-developed Haversian systems, separated by frequent wide

100 J. S. FOOTE, M. D.

canals, which pass to an apex at the outer surface of the ridges. The

external circumferential lamellae are absent at these points and

tendon insertions, interspersed by many canals, occupy the ridges.

The peculiar features of the bone are its undeveloped condi-

tion and its resemblance to the femurs of the peahen and turkey.

The eagle’s medullary canal is empty, like that of the peahen, but

its laminar structure is more like that of the turkey. The type is

incomplete laminar.

Femur of the Hawk.

PL, Bigs 12:

Antero-posterior diameter of bone, 4 mm.; lateral, 4.3 mm.

Antero-posterior diameter of medullary canal, 3 mm.; lateral,

3.3 mm.

The medullary canal is empty. The bone is hard.

Structure. The section is surrounded by four to six external

circumferential lamellae, fairly well developed. Their lacunae are

more frequently oval than long. This fact indicates a less complete

development. The canaliculi are bushy.

In the inner lateral posterior wall is a ridge to which are at-

tached muscle tendons penetrating the external lamellae. Under-

neath the external circumferential lamellae is a thick ring of in-

complete Haversian systems with oval lacunae and short, bushy

canaliculi. The ring is crossed at all angles by wide, irregular canals,

which are mostly confined to the ring. The Haversian systems are

most prominent and best developed near the ridge of the lateral

posterior region. This central Haversian system ring blends with

the external circumferential lamellae.

The medullary canal is enclosed by six or eight well-developed

internal circumferential lamellae with long lacunae and canaliculi.

It is distinct from the central ring. No cancellous bone.

The peculiar feature of the bone is its low development. The

type is incomplete Haversian system.

HISTOLOGY OF FEMORAL BONES IOI

Femur of a Grouse.

Pl. II, Fig. 13.

Antero-posterior diameter of the bone, 5 mm.; lateral, 5.5 mm.

Antero-posterior diameter of the medullary canal, 4 mm.;

lateral, 5 mm.

The medullary canal is empty. Trabecule are present in the

lower third. The bone is soft. No cancellous bone.

Structure. There are no distinct external circumferential

lamellae. The bone, with the exception of a narrow ring of internal

circumferential lamellae, is composed of short concentric laminae,

separated by wide canals. Each lamina consists of two to four

lamellae, with long, narrow or oval lacunae and long, branching or

bushy canaliculi. The canals freely communicate with each other

across the laminae. In the anterior wall (middle portion) is a

slight prominence or ridge, consisting of three or four poorly-

developed Haversian systems, situated close to the external surface

and several whorls of lamellae arranged around short canals running

in different directions. In the posterior wall are two ridges sep-

arated by a concave surface of bone. A single, poorly-developed

Haversian system is found at the apex of each ridge, around which

are collections of oval lacunae, with short, bushy canaliculi. Close

to the internal circumferential lamellae are a few Haversian systems

of a crude type.

Internal circumferential lamellae, three or four in number,

surround the medullary canal. Their lacunae are long and narrow.

The type of bone is the laminar.

The peculiar feature is the absence of complete Haversian

systems. The bone resembles that of a turkey.

Femur of the Domestic Chicken.

PTW) Pigeta

Antero-posterior diameter of the bone, 9 mm.; lateral, 9 mm.

Antero-posterior diameter of the medullary canal, 7 mm.;

lateral, 7 mm.

The bone is practically round. The medullary canal is full. No

trabecule and no cancellous bone. It is of medium hardness.

102 J. S. FOOTE, M. D.

Structure. 1. Well-marked external circumferential lamellae,

three to five in number, with long, narrow lacunae and branching

canaliculi. They are quite distinct from the remainder of the bone.

2. A wide ring of irregularly-shaped, incompletely-developed -

Haversian systems. Some of the systems are circular in cross sec-

tion, but most of them exhibit no definite shape. They run in various

directions, are better developed on the outer side than on the inner

side and tend to centralize at the posterior ridge and anterior surface.

At the posterior ridge they occupy the entire thickness of the wall

of the bone as far as the internal circumferential lamellae. At the

ridge surface canals and bone lamellae take a direction at right angles

to the long axis of the shaft. Along the anterior surface the systems

are better developed and extend a short distance on both sides of the

middle line. Interspersed between the systems are short lamellae.

The lacunae of the systems are oval and the canaliculi are short and

bushy. The Haversian canals are prominent in some places where

they form a network, while in other places they form a parallel

system.

3. Internal circumferential lamellae, four or five in number,

completely surrounding the medullary canal. Their lacunae are

long and narrow and their canaliculi are bushy.

Both external and internal lamellae are well-developed and dis-

tinct from the Haversian ring. The bone is of the Haversian system

type undeveloped.

Femur of the Prairie Chicken.

Pl igs:

Antero-posterior diameter of the bone, 5 mm.; lateral, 6 mm.

Antero-posterior diameter of the medullary canal, 4 mm.;

lateral, 4.5 mm.

The medullary canal is empty. Trabecule are present. The

bone is soft. No cancellous bone.

Structure. There are no distinct external circumferential

lamellae. The bone is composed of crude lamellae, crossed at all

angles by short canals, some of which extend inward from the

external surface. In the posterior and outer walls they unite and

form a coarse network, while in the anterior and inner walls they

PLATE II

SS =

Posterior 7 ss

anterior ; ;

: {yrregular,

Miaikt PosterLory vidge incomplete

Haversian

Systems... *

Laminae of

the theelc

internal

Circumferential

lamellae ..

Right or External

yi CivCumferyential

mn Oe ea lavnatlce

¥ uniting

a Haver Sian Canals.

Fig.8 :

« Showing F1g.10

Femur of amallard Duck $I

Extarnall intenwal lamellae and anterior Surface Section of the femur of the large

Varlous Combinations oa _teregudar Figg horned owl Showing athin and of

laminae and HaverSian systems. : D showing external Circumferential lamellae

Femur of wild g008¢ § beans incomplete Haversian Systems and.

Ws ———____— tncom plete oY eno ems, FRick band of mye Bon eta erential

5 7 7; 5 5 ellae amellae anc prominent uwniki Haver Sia)

anterior : Ey laminae and lam ret nel pb in neting Have q

-——____+

Interior wal

Laminate

Laminae

Canals

Internal

Inn an ‘ Lamellae

Tnnew

~WaLL

Tendon poe

insertions. Fig. 1

reese Femur of a Hawk

Poslervon vidges Showing well bl eloped external and Femum of Grouse (Blue), Showing

Fug. internal lamellae and undeveloped Laminar Structure.

Central Haversian systems

Femur of an Eagle,

HISTOLOGY OF FEMORAL BONES 103

do not. The lamellae are not distinct, but are blended together.

Their lacunae are oval or narrow and their canaliculi are bushy or

long and branching.

A very few crude Haversian systems are found interrupting the

lamellae of the anterior and inner walls. They have only three or

four lacunae around a minute canal. Their canaliculi are few. In the

posterior wall are two ridges separated by a concave surface of

bone. Two or three undeveloped Haversian systems are found in

each ridge.

The internal circumferential lamellae, four to six in number,

surround the medullary canal. They are well developed. Their

lacunae are long and narrow and their canaliculi are long and branch-

ing. The type of bone is lamellar.

The peculiar features are the general absence of Haversian

systems and the crude lamellar formation. The bone is not as far

advanced as that of the grouse (Blue). |

Femurs of the Domestic and Wild Turkey.

PE TIE Wigs: 16),57.

Domestic turkey. Antero-posterior diameter, 15 mm.; lateral,

17.5 mm.

Antero-posterior diameter of medullary

canal, 10.5 mm.; lateral, 13 mm.

Wild turkey. Antero-posterior diameter, 9 mm.; lateral,

II mm.

Antero-posterior diameter of medullary

canal, 7 mm.; lateral, 8 mm.

Since the two bones resemble each other closely, one description

will answer for both. The medullary canals are full. No trabecule;

no cancellous bone. The type of structure is laminar. The bones

are soft. The medullary canals are relatively large and the walls

of the bones are thin.

Structure. Around the outside are four or five external circum-

ferential lamellae, between which are long, narrow lacunae, with

many canaliculi. Along the posterior ridges of the two femurs are

small areas of incomplete, irregularly-shaped Haversian systems

which occupy nearly the entire thickness of the posterior walls of

104 J. S. FOOTE, M. D.

the bones. They extend nearly to the outer surfaces, where they

seem to be projected in a network of bone extensions, which pass

to the surfaces of the posterior ridges, where they blend with the

tendon attachments. In the anterior walls are small areas of the

same irregular Haversian systems. The systems do not reach either

surface. In both of these regions the systems do not appear to run

parallel with the outer and inner surfaces of the bones, but extend

in different directions. Since their cross sections are circular, ellip-

tical, angular and very irregular in shape, no one direction could

be followed by all. The Haversian canals are large, the lacunae are

oval and their canaliculi are numerous and bushy.

Between the posterior ridges and middle anterior surfaces, and

constituting eight-tenths of the whole section of the bones, are con-

centric laminae, fifteen to eighteen or twenty in number, separated

by prominent canals and crossed at frequent intervals by smaller

canals extending from both surfaces of the bones. The laminae

are composed of three or four lamellae, between which are oval

lacunae, with short, bushy canaliculi. Here and there a lamina is

interrupted by a Haversian system.

Around the medullary canal the internal circumferential lamellae

are not distinct from the adjoining laminae. The peculiar feature of

the turkey femurs is the laminar formation.

It may be noticed that the Haversian systems present in the

section are found in the posterior walls and ridges and in the

anterior walls, where muscular stress is greatest.

Femur of the Peahen.

Pl. III, Fig. 18.

Antero-posterior diameter of the bone, 10 mm.; lateral, 11 mm.

Antero-posterior diameter of medullary canal, 8 mm.; lateral,

10 mm. Bone is thin; medullary canal is large, empty; has a net-

work of trabeculae which extends from one wall in a downward

direction to the opposite wall. They are most numerous near the

extremities of the bone. No cancellous bone. The bone is ex-

tremely hard.

Structure. The usual three divisions of the bone into external

circumferential lamellae, middle ring of Haversian systems and in-

HISTOLOGY OF FEMORAL BONES 105

ternal circumferential lamellae do not appear. The bone consists of

a network of canals separating short, concentric laminae. The canals

intersect at all angles. They are wide. The laminae are composed

of four or five lamellae with oval lacunae and relatively few rather

short, bushy canaliculi. In the vicinity of the posterior ridge a few

incomplete Haversian systems are found. In other parts of the

section, here and there, a system appears without any apparent

signification. The bone is peculiar in the absence of Haversian

systems. The bone trabeculae are composed of three or four

lamellae with long, narrow lacunae and branching canaliculi. A few

systems are present. The bone is of the laminar type, but does not

show a development equal to that of the turkey. However, it be-

longs to the same structural type and can be recognized as such with

no difficulty.

Femur of a Yellow Hammer.

PVE Pigs 10:

Antero-posterior diameter of the bone, 2.5 mm.; lateral, 3 mm.

Antero-posterior and lateral diameters of the medullary canal,

0.5 mm.

The medullary canal is full and situated close to the posterior

wall. The bone is soft.

The femur consists of a wall of compact bone, composed of

three or four external circumferential lamellae and about the same

number of internal circumferential lamellae, between which are a

few irregularly-developed Haversian systems. Large canals extend

transversely across the walls of the bone communicating with the

meshes of the central bone structure.

The central portion of the bone usually occupied by the

medullary canal is composed of a fine cancellous bone formation,

with the exception of a fine medullary canal about the size of a

fine sewing needle, situated close to the posterior wall. The femur

is therefore nearly solid bone. The cancellous center is composed

of fine lamellae forming a meshwork extended from the internal

circumferential lamellae. The meshes are filled with granular ma-

terial, insoluble in ether or chloroform. It is difficult to grind out this

106 J. S. FOOTE, M. D.

material and leave uninjured the meshwork. The lacunae are small,

round or oval and their canaliculi are short, bushy and infrequent.

Round and oval lacunae appear to be antecedent forms of long,

narrow lacunae. In undeveloped Haversian systems the lacunae are

round or oval, while in the complete systems they are long and

narrow. It is possible that the pressure of development accounts for

the variation in shape—the medullary canal is full and extremely

small. Its position is unlike that of other canals.

The peculiar features of this femur is the central bone form-

ation and small eccentric medullary canal. Although the yellow

hammer is a good flyer, its femur is practically a solid bone. The

type is lamellar-cancellous.

Femur of the Crow.

Pl: TV, Fig: 20:

Antero-posterior diameter of the bone, 4 mm.; lateral, 3 mm.

Antero-posterior diameter of medullary canal, 2.5 mm.; lateral,

2mm.

The medullary canal is full. No trabeculze and no cancellous

bone. The bone is soft.

Structure. 1. External circumferential lamellae, six or eight

in number, form a wide lamina around the bone. The lamellae are

not clearly defined, the lacunae are oval, with bushy, connecting

canaliculi. A little to the outer side of the anterior mid-line, the

lamina dips down and forms a semi-circular depression about 14 mm.

in diameter.

2. A central wide ring of transverse canals, enclosed by in-

complete Haversian systems and irregular lamellae. Their lacunae

and canaliculi are the same as above described. There is very little

difference in the structure of the various parts of the bone. Possibly

the Haversian systems are a little better developed in the posterior

wall.

3. Internal circumferential lamellae, two or three in number,

form a narrow ring around the medullary canal. Their lacunae are

narrow and long and their canaliculi are long and branching.

The bone is of the mixed type. The peculiar features are the

external lamina, uniform central ring and semi-circular depression.

PLATE AIL

+ ——+

Ivregular

HaverSian

Systems o

posterior

ridge.

Fifteen to

Seventeen

laminae...

Irregulay

Haveystan

Systems on

Vidge.......

Femur of domestic chicken Femur of a Prairie Chicken Fig. d6

showing external ,internal lamellae Showing lamellae type. Femuronde ais .

Gnd irregulay HaverStan Systems, laminae i Shh es tc Cuykey Showing

Systems on anherinean ae ane

iy on Gntertoy and posterior vidges.,

«i

Tyyvegular ‘ ‘

HaverSian 4

Systems oF Posterior ridge antercen.

postertov incomplete wall

viage Haversian SyStems.

Fifteen to Haversian Canals COM pon

eighteen

Laminae..

laminae Cancellous

btone....

Trabecula... Ewe

nulay

Bee matevial. ... 4.

Systems o a medullary

Antertor Canal....—

ridge Se :

Posterior

F 2 wall....———

Fig-/7 anterloy Surface. : Fig. /9

Section o the femur of awild 719-8 le

turkey Showing laminae and ane: of 0 ganey peeve a network ecuaa ° peltans etten Eu lre rely eoae

tyre gular HaverStan Systems on of aversia Canals, or eee oe,few edutlary nal near posterior wall. Thefemar

: ; = H. sian systems and trabeculae ofbone is nearly all bone from one wall to another. The

anterior and posterior ridges. tthe k A) : Pechie LeTRC Genin lhena aha felled With granular

material

HISTOLOGY OF FEMORAL BONES 107.

Femur of a Blue Jay.

PL: IV, Fig: 21.

Antero-posterior diameter of bone, 2.5 mm.; lateral, 2.5 mm.

Antero-posterior diameter of medullary canal, 2.5 mm.; lateral,

1.5 mm.

The bone is nearly round. The medullary canal is full. The

bone is hard.

Structure. The anterior and outer walls are composed of four

or five incompletely-formed laminae, frequently uniting. The

laminae consist of three or four lamellae. The inner and posterior

walls are composed of lamellae interrupted by a few incompletely-

developed Haversian systems. The lacunae are oval. The canaliculi

are few and short.

The type of bone is lamellar. The peculiar feature of the bone

is its close conformity to the lamellar type and absence of Haversian

systems.

Femur of the Opossum.

Pl IV, higi23

Antero-posterior diameter of the bone, 7 mm.; lateral, 8.5 mm.

Antero-posterior diameter of the medullary canal, 3.5 mm.;

lateral, 5 mm.

Medullary canal is full. No trabecule and no cancellous bone.

The bone is soft.

Structure. The bone presents a rudimentary appearance. It is

composed of two wide external lamellar bands of incomplete form-

ation separated by a very narrow band of imperfectly-developed

Haversian systems, the whole occupying two-thirds of the posterior,

outer and anterior walls. The lamellar bands simply give the

general appearance of lamellae, but are really composed of large oval

lacunae, with extensive, bushy canaliculi forming an intricate net-

work. At short intervals short transverse canals appear, with many

radiating canaliculi. Just internal to this lamellar band is a narrow

crescent of very incomplete Haversian systems occupying the an-

terior, outer and posterior walls. The systems are merely canals,

from which radiate numerous straight canaliculi, with a few oval

lacunae around their apparent circular boundaries. Around the

108 J. S. FOOTE, M. D.

medullary canal of the anterior, outer and posterior walls internal

circumferential lamellae are well developed, reaching their greatest

thickness in the outer wall. Their lacunae are long and narrow and

their canaliculi are long, straight and branching.

The inner wall of the bone is extended in the form of a heavy

ridge. It is composed of heavy, oblique canals, from which are sent

off dense networks of large canaliculi. This peculiar arrangement

forms the external half of the ridge. The internal half consists of

incomplete Haversian systems, arranged in oblique rows, converging

to a central point in the middle of the ridge. The systems are

similar to those described above. No internal circumferential

lamellae are found in this region. The bone is very poorly developed

and belongs to a type of structure characterized by incomplete de-

velopment.

The peculiar features are the undeveloped lamellar and Haver-

sian systems and the heavy oblique canals. The only complete struc-

ture is the partial internal circumferential ring of lamellae.

Femur of the Musk Rat.

Pl. TV; Fig. 24:

Antero-posterior diameter of the bone, 5 mm.; lateral, 6.5 mm.

Antero-posterior diameter of medullary canal, 2.5 mm.; lateral,

3 mm.

Medullary canal has no contents. From the medullary surface

of the inner wall project a few fine trabeculae. No cancellous bone.

The bone is soft.

Structure. The bone is peculiar in many respects. The inner

wall of the bone is extended in the form of a ridge, which is com-

posed of a network of laminae and canals running transversely from

above downwards and occupying the outer four-fifths of the ridge.

Each lamina consists of two or three lamellae, with long or oval

lacunae and long branching or bushy canaliculi. The inner one-fifth

of the ridge wall consists of a network of laminae running from

the medullary canal to the outer network. Within its meshes are

found canals from which radiate many long, branching canaliculi.

The remainder of the bone (anterior, outer and posterior walls) is

composed of a very irregular, wide internal ring of lamellae sur-

HISTOLOGY OF FEMORAL BONES 109

rounding the medullary canal and having an outer wavy border, in

some places distinct and in other places fused with an external net-

work of laminae. Very many canals cross the lamellae on their way

from the medullary canal to the interior of the wall. Within the

lamellar ring are several round or elliptical bodies composed of 6-8

lamellae running lengthwise of the cross section. These bodies are

such as would result from a transverse section of solid pillars. In

the outer wall of the bone, lamellae form the entire thickness.

Here and there occurs a very incomplete Haversian system, consist-

ing of a central canal and radiating canaliculi.

The bone is of the lamellar type modified. Its peculiar features

are the networks of laminae and canals, the irregular lamellae, the

circular or elliptical solid bodies, and the numerous canals.

Femur of a Rat.

PEV Hig, 25.

Antero-posterior diameter of the bone, 2.5 mm.; lateral, 3.5 mm.

Antero-posterior diameter of the medullary canal, 1.5 mm.;

lateral, 2.5 mm.

The medullary canal is full. No trabeculze and no cancellous

bone are present. The bone is soft.

The bone has a prominent ridge in the outer wall and is some-

what egg-shape in transection.

Structure. It 1s composed of two concentric rings of about

equal width surrounding the medullary canal. The external ring

consists of lamellae, varying in number from thirteen to fifteen in the

outer ridge to six or eight in the anterior and posterior walls and

ten to twelve in the inner wall. The lacunae are long and narrow

and their canaliculi are long and branching. Here and there cross

canals appear. The internal ring consists of a network of canals,

enclosing few incomplete Haversian systems, short lamellae or

laminae and, in some places, fine network of canaliculi. The lacunae

are oval and round and the canaliculi are bushy. The lamellae

are complete. The internal circumferential lamellae are so blended

with the other structures of the internal ring that they are poorly

defined.

110 J. S. FOOTE, M. D.

The bone is lamellar in type. Its peculiar features are the two

rings, one external complete lamellae and the other internal incom-

plete Haversian systems and canalicular network.

Femur of the Rabbit.

PITY iig:. 26:

Antero-posterior diameter of the bone, 5.5 mm.; lateral, 7.5 mm.

Antero-posterior diameter of medullary canal, 3.5 mm.; lateral,

5 mm.

The medullary canal is full. No trabecule and no cancellous

bone are present. The bone is soft.

Structure. 1. Around the bone is a ring of lamellae of varying

thicknesses. As a whole it is narrow, and, in the posterior wall,

merges into oblique laminae which join the internal circumferential

lamellae. The lacunae are long and narrow and the canaliculi are

long and branching.

2. There is a wide central ring of incomplete Haversian sys- |

tems and short, irregular laminae occupying the anterior and inner

walls. In the posterior wall this ring is interrupted by oblique, well-

developed Haversian systems and laminae extending from the in-

ternal to the external circumferential lamellae. In the outer wall

there are wide, oblique canals separating irregular laminae extend-

ing from the internal to the external lamellae and interdigitating

with extensions from the periosteum. These two oblique arrange-

ments enclose a small crescent of irregular systems and lamellae.

The lacunae are oval or long and the canaliculi are bushy.

3. Internal circumferential lamellae of varying thickness and

well-developed surround the medullary canal. In the inner and

posterior walls it merges into oblique, wide laminae, separated by an

oblique row of complete Haversian systems. To the outer side of

this row of systems are three or four wide, oblique laminae which

appear to be extensions of the internal lamellae.

The bone is of the mixed type. Its peculiar features are the

oblique Haversian systems and laminae.

Fg. 20

Femur of Crow Showing

depression and trregulay Systems,

lamina,

anterior wall,

hetwork of

laminae...

Solid

elliptical body.

Fig. 2 4-

Bes oF Gs Rak Showing a very

ultay arrangement of laminae

ra incomplete Haversian Une

wall .

nner wall,

Right femuy of a Rlue Fay Showing

laminae. lamellae and a very few

HaverySian Systems,

PLOATE IV

wall...

Fig: 24

Fig. 23

Femur of the Opossum Showing

tncom blete lamellae Havers:

Cystorns and heavy do6ligue Canals,

Femur of a rat Showing wide Yingsof

external Circumferential Lameilae

and internal incomplete Haverstan

Systems and lamellae with a network

of Canals,

Frg.26

Femur of a rabbit Showing lamellae,

Haversian Systems and obligue laminae,

HISTOLOGY OF FEMORAL BONES EEE

Femur of the Woodchuck or Ground Hog.

Ply.V5 Bigh27:

Antero-posterior diameter of the bone, 6 mm.; lateral, 7 mm.

Antero-posterior diameter of the medullary canal, 4 mm.;

lateral, 4.5 mm.

The medullary canal is full. It has no trabecule nor cancellous

bone. The bone is soft.

Structure. 1. Two well-developed external laminae, dis-

tinctly separated, form the circumference of the bone. In the pos-

terior portion of the outer wall they fuse and form a single lamina.

Each lamina is composed of five or six lamellae with large round

or oval lacunae and bushy canaliculi. In the center of each lamina,

and concentric with their boundaries, is an incomplete ring of crude

Haversian systems. The two laminae are separated by a wide canal.

The external lamina is thickest in the inner wall.

2. Acentral ring of rugged, irregularly-shaped Haversian sys-

tems between which are short lamellae with no apparent regularity.

In some places the lamellae are merged into laminae. The lacunae

of the Haversian systems are long, their canaliculi are thickly set,

long and branching and their lamellae are distinct.

3. Two well-developed internal laminae distinctly separated

from each other. Each lamina is composed of five or six lamellae

with large round or oval lacunae and long canaliculi. At one point

(A) of the medullary surface of the inner wall are seen outgrowths

from the medullary canal breaking through the laminae.

The bone is of the complete mixed type. Its peculiar features

are the strongly-developed external and internal laminae, the irreg-

ular character of the Haversian systems and the medullary out-

growths.

Femur of the Prairie Dog.

Pl. V, Fig. 28.

Antero-posterior diameter of the bone, 4.5 mm.; lateral, 5 mm.

Antero-posterior diameter of medullary canal, 2.5 mm.; lateral,

3 mm. yatig 43

The medullary canal is empty. No trabeculz and no cancellous

bone. The bone is soft.

II2 J. S. FOOTE, M. D.

Structure. 1. External circumferential lamellae, eight to fif-

teen in number, form an irregularly wide ring, which reaches its

greatest width in the inner wall. The lacunae are long and narrow

and the canaliculi are long.

2. A narrow central ring of incomplete Haversian systems.

Their lamellae are indistinct, their lacunae are oval and their canali-

culi are bushy.

3. A very wide ring of internal circumferential lamellae, six

to twenty-five in number. The ring is widest in the anterior wall.

Their lacunae are long and narrow and their canaliculi are long.

Numerous canals pass from the medullary canal across the lamellae

into the interior of the bone.

The bone is of the lamellar type, with a few Haversian systems

of an incomplete formation.

Femur of the Skunk.

PL, Fig. 20:

Antero-posterior diameter of the bone, 5 mm.; lateral, 5 mm.

Antero-posterior diameter of medullary canal, 3.5 mm.; lateral,

mm.

7 Medullary canal is full. No trabeculz and no cancellous bone.

The bone is of medium hardness.

Structure. 1. A thick ring of external circumferential lamel-

lae, fourteen to seventeen in number, in the middle of which is a

concentric row of very incomplete Haversian systems. The lamellar

ring is interrupted in the posterior wall by Haversian systems. The

lacunae of the lamellae are long and branching or short and bushy.

The concentric row of Haversian systems within the external

lamellae consists of Haversian canals, a short distance apart, around

which are one or two indistinct lamellar with oval lacunae and short,

bushy canaliculi.

2. A narrow, somewhat irregular ring of poorly-developed

Haversian systems, the canals of which frequently unite. This ring

widens at the posterior wall, where it occupies the entire thickness

of it, excepting the internal circumferential lamellae. The lacunae

are oval and few and their canaliculi are short and bushy.

HISTOLOGY OF FEMORAL BONES 113

3. Internal circumferential lamellae, thin in the posterior wall,

six to eight in number and very thick elsewhere, eighteen in number.

In the outer wall this ring has a concentric central row of incomplete

Haversian systems. The lacunae are long and narrow and their

canaliculi are long and branching. Many canals pass through this

lamellar ring on their way from the medullary canal to other canals

in the interior of the wall.

The bone is of the mixed type. Its peculiar features are the

wide rings of lamellae with central rows of Haversian systems and

incomplete development.

Femur of the Raccoon.

Pl. V, Fig. 30.

Antero-posterior diameter of bone, 9 mm.; lateral, 10 mm.

Antero-posterior diameter of medullary canal, 6.5 mm.; lateral,

7 mm.

Medullary canal is full. No trabeculz. No cancellous bone.

The bone is of medium density or hardness.

Structure. 1. External circumferential lamellae, fourteen to

fifty in number, according to locality. In the anterior wall the lamel-

lar ring is thin, being composed only of a few lamellae, while, in

the posterior and inner walls, it reaches its greatest thickness, form-

ing in those regions two-thirds of the entire thickness of the bone.

Numerous canals appear at short intervals within the ring. Within

the wide lamellar ring of the inner wall are found many rather in-

complete Haversian systems. The lacunae of the lamellae are long

and narrow and the canaliculi are long.

2. An irregularly-shaped ring of Haversian systems well de

veloped. In the middle of the posterior wall it is thin, one-third or

one-fourth of the thickness of the wall. It gradually increases in

thickness in the outer wall until it reaches about the middle, where

it forms two-thirds of the width of the wall. From this point it

continues to increase to the middle of the anterior wall, where it

forms four-fifths of the bone. The systems are strongly developed.

They have three to five well-marked lamellae, their lacunae are long

and narrow and their canaliculi are long and branching. Between

114 J. S. FOOTE, M. D.

the systems are short lamellae. The Haversian canals frequently

unite. In the middle of the lamellar ring of the outer wall are thirty

to thirty-five very distinct Haversian systems separated by lamellae.

These systems seem to form a group by themselves without any

especial signification.

3. A ring of internal circumferential lamellae and laminae of

varying thicknesses. In the anterior wall only a few lamellae

appear. The Haversian systems almost border the medullary canal.

In the outer wall extending around the posterior region are short,

oblique laminae, forming in some places nearly one-half of the

thickness of the bone. In the inner wall two or three laminae form

the medullary boundary. The lacunae are long and narrow and the

canaliculi are long and branching.

The femur is of the mixed type. The peculiar features of the

bone are the wide external lamellae, the irregular arrangement of

the Haversian systems and the oblique internal laminae (compare

os penis, Fig. 32).

Os Penis of the Raccoon.

Pe Voniaiow 32:

The os penis is introduced here because it resembles the Haver-

sian system type of femurs.

The antero-posterior diameter of the bone is 4 mm.; lateral,

4 mm.

The antero-posterior diameter of the central canal is 0.8 mm.;

lateral, 0.8 mm. The canal is very irregular in shape. The bone

is of medium hardness.

Structure. 1. External circumferential lamellae, seven to

twelve in number, and rather incompletely developed. They are not

equally distinct in all parts. In some places they are fairly well de-

veloped, while in others they are indistinct and interrupted by small,

incompletely-formed Haversian systems. The lacunae are large, few

in number, oval in shape and have branching canalicull.

2. A wide ring of large and small Haversian systems. The

large systems occupy the inner portion of the ring, the small ones the

outer portion. They are all fairly well developed. Their Haversian

canals frequently communicate with each other, their cross sections

HISTOLOGY OF FEMORAL BONES 115

are circular, their lacunae are few, long and narrow, their canaliculi

are long and branching and their lamellae are not clearly defined.

Here and there short inter-Haversian lamellae appear.

3. Internal circumferential lamellae, six or eight in number,

which form a very irregular boundary of the medullary canal by

the formation of large cancellous spaces. The lamellae seem to be

folded into cancellous structures. The lacunae are long and their

canaliculi are very numerous and branching.

The peculiar feature of this bone is its close resemblance to

the structure of some femurs. This resemblance is unexpected,

since the requirements of the two bones are apparently quite dif-

ferent. The inference is that the structure of a bone is governed

more by the individual, formative character present in an animal than

by the function; that is, when a bone is formed the forces at work

in the arrangement of its structural units are the same in all parts

and the same type of bone is constructed in the penis as elsewhere.

Femur of the Mink.

Pi Viigo. aur.

Antero-posterior diameter of the bone, 3.5 mm.; lateral, 4.5 mm.

Antero-posterior diameter of the medullary canal, 1.5 mm.;

lateral, 2 mm.

The medullary canal is full. No trabeculae and no cancellous

bone.

Structure. The usual arrangement of lamellae and Haversian

systems is not present in this bone. A portion of the anterior wall

consists of 50-60 lamellae, forming the entire thickness of the

bone. These lamellae then diminish in number to 25-20-12, and

form an irregular complete ring around the medullary canal. Numer-

ous canals pass across this ring, incompletely or completely, on their

way from the medullary canal to small canals of the interior. The

lacunae are long and narrow and their canaliculi are long and

branching.

The Haversian systems are absent at the widest lamellar point.

They then begin to appear, in single file, gradually increase in thick-

ness to the posterior wall and diminish again as they approach the

anterior wall. In this manner they form an irregular crescent en-

116 J. S. FOOTE, M. D.

closed within outer narrow lamellae and wide inner lamellae. The

crescent nearly encircles the bone. The Haversian systems are fairly

well developed, their lamellae rather indistinct, their lacunae oval

and their canaliculi relatively few. Their canals frequently unite.

In some places bands of lamellae cross the crescent extending from

the outer to the inner lamellae. Numerous canals traverse the cres-

cent. The internal circumferential lamellae form a wide, irregular

ring, fusing with the external lamellae in the anterior wall. Many

canals cross them. The lacunae are long and narrow and their

canaliculi are long and branching.

The bone is of the mixed type. The peculiar features of the

bone are the wide internal lamellar ring, with its many canals, the

narrow external lamellar ring and the long crescent of Haversian

systems.

Femur of a Weasel.

PIV i, Figs 33:

Antero-posterior diameter of the bone, 1.5 mm.; lateral, 2 mm.

Antero-posterior diameter of the medullary canal, 1 mm.;

lateral 2 mm.

The medullary canal contains a very thin layer of marrow

around the walls of the bone. There are no trabecule. The bone is

soft. No cancellous bone.

Structure. There are no distinct external and internal circum-

ferential lamellae. The anterior walls are thicker than the posterior.

The bone consists of twenty to twenty-eight concentric lamellae.

Their lacunae are narrow and oval and their canaliculi are long,

branching or bushy. The lamellae are fairly well developed. In the

outer anterior wall they are interrupted by irregularly-shaped whorls

of oval and round lacunae, with short, bushy canaliculi. In one or

two of them a central canal appears. The whorls are evidently

the early stages of Haversian systems. Besides these not a single

Haversian system can be found. Large canals cross the bone on

their way from the medullary canal to the external surface. They

are not numerous. The type of bone is the lamellar.

The peculiar feature is the complete absence of Haversian

systems in a mammalian femur.

PLATS V

= ae

antercor wall.

Antertor wall _

Femuy of wood¢huck oY ground

hog Showing two well developed

external and tnternal laminae and

wregular 4averStan Systems,

Femuy, of

Q pratyie POS

wide external/internal circumferential

lamellae and narrow ring of Haverstan

Systems,

Showing

Fig.3)

amink Showing wide

lamellae Crescent af HaverSian Systems

and numerous Canals.

Fig.30

Femuy of GPACCOOM Showing wide

lamellae, ivyegular arrangement of

HaverSian Systems and internal lamenac.

Femur o

anrerioy

wall...

Haversian

Systems...

Central

Canal...

Fig.29

Femur of @ Skunk Show la ae

Character fe the bone, oe eae

779. 32

Cross Section of the o$ bens

of the raccoon.

HISTOLOGY OF FEMORAL BONES HEL)

Femur of the Wild Cat.

Pl Vij iig. 34:

Antero-posterior diameter of the bone, 13.5 mm.; lateral,

Ir mm.

Antero-posterior diameter of the medullary canal, 8 mm.;

lateral, 5.5 mm.

The medullary canal is full. No trabeculze and no cancellous

bone are present. The bone is hard.

Structure. 1. Around the outside of the bone is a wide ring

of lamellae, interrupted very frequently by incomplete Haversian

systems. The ring forms two-thirds of the thickness of the walls of

the bone, excepting in the posterior wall, where the central Haversian

systems occupy the whole width from the internal circumferential

lamellae outward to the circumference. As this ring approaches

the posterior wall on the inner side the lamellae separate into laminae.

Many canals traverse the ring. For the most part, all of the

structural units are indistinct. Around the anterior and a portion of

the inner wall is a narrow rim of lamellae, 4-6 in number. The

lacunae of the wide lamellar ring are long or oval and their canaliculi

are long and branching or bushy. In some places there is a network

of lacunae and their canaliculi, a formation which belongs to the

lower orders of development.

2. In the anterior wall there is a short crescent of well-

developed Haversian systems adjacent to the internal circumferential

lamellae. In other portions there is an irregular arrangement of

Haversian systems and laminae, complete and incomplete. In the

posterior wall a narrow ring of well-developed Haversian systems

appear, which is gradually lost in the wide lamellar ring.

3. Around the medullary canal is a well-defined ring of internal

circumferential lamellae, varying in thickness from three or four in

the posterior wall to thirty in the anterior wall. Numerous large

canals cross the ring to communicate with canals within the center

of the bone. The lacunae are long and canaliculi long and branched.

The bone is of the lamellar type, principally.

118 J. S. FOOTE, M. D.

Femur of the Cat.

Pl Wi, Fig: 35:

Antero-posterior diameter of the bone, 7.5 mm.; lateral, 9.5 mm.

Antero-posterior diameter of medullary canal, 4 mm.; lateral,

5.5 mm.

Medullary canal is full. No trabecule. No cancellous bone. The

bone is of medium hardness.

Structure. 1. External circumferential lamellae, twenty-three

to forty-five in number, form about one-half of the thickness of the

wall of the bone. They are inclined to interlace. Near the mid line

of the anterior wall four Haversian systems appear in the middle of

the lamellar ring. They are well developed and without apparent

signification. A short distance from the mid line in the inner wall

the lamellar ring divides into a wide outer and narrow inner parts

which enclose a crescent-shaped area of Haversian systems. Along

the posterior wall a few scattering, incomplete Haversian systems

are introduced into the lamellar ring. About the middle of the inner

wall is quite a sharp lateral ridge formed by lamellae. The lamellar

ring is widest at this point and narrowest in the outer wall. The

lamellae, for the most part, are clearly developed and show no

signs of a laminar formation, excepting in the anterior wall, where

there is a slight tendency toward such an arrangement. The lacunae

are long and narrow and the canaliculi are thickly set, long and

branching.

2. A ring of well-developed, large and small Haversian sys-

tems, widest in the inner wall and narrowest in the outer wall. The

ring has irregular boundaries. The systems are generally strongly

developed, and are round, elliptical or irregular in cross section.

Their lamellae are clearly marked, their lacunae are long and

narrow, their canaliculi branching and their Haversian canals are

frequently united. Inter-Haversian lamellae, short and irregular,

hold the systems together.

3. The internal circumferential lamellae are in the form of

two or three laminae in some places and five or six in others. Each

lamina is composed of four to six lamellae. Their lacunae are

long or oval and their canaliculi are bushy. The laminae do not

HISTOLOGY OF FEMORAL BONES 119g

present parallel sides, but are wide or narrow, and hence the width

of their internal ring varies. Numerous canals pass through the

laminae on their way from the medullary canal. The bone is of the

lamellar type. The peculiar feature of this bone is the extremely

thick ring of lamellae.

Femur of a Small Grey Fox.

Pie NV ieign 220:

Antero-posterior diameter of the bone, 8 mm.; lateral, 9 mm.

Antero-posterior diameter of medullary canal, 5 mm.; lateral,

6.5 mm.

The medullary canal is full. No trabecule and no cancellous

bone present. The bone is soft.

Structure. 1. A ring of external circumferential lamellae,

twenty to thirty in number, surround the bone. In the outer wall the

lamellar ring is distinct, but in the inner wall it widens and merges

into laminae, which occupy the whole thickness of the wall. The

laminae are short and are separated and crossed by intercommun-

icating canals. On the inner side of the posterior wall is a ridge

and the laminae from the inner wall reach the surface at this point

and appear to interdigitate with inward extensions from the peri-

osteum. The lacunae are long and narrow, the canaliculi are long

and branching.

2. <A crescent of well-developed Haversian systems, the horns

of which begin a short distance apart in the inner wall, while the

widest part of the body occupies the outer wall. The systems are

small and large, regular and irregular in shape. Their lamellae are

well defined, their lacunae are long and narrow and their canaliculi

are branching. Their Haversian canals frequently communicate.

3. Around the medullary canal is a border of Haversian

systems, flattened, a few laminae and some lamellae.

The bone is of the complete mixed type. Its peculiar features

are the arrangements of the lamellae, laminae and Haversian systems.

120 J. S. FOOTE, M. D.

Femur of the Wolf.

PL Vi, Fig. 37:

Antero-posterior diameter of the bone, 16.5 mm. ; lateral, 7 mm.

Antero-posterior diameter of the medullary canal, 10 mm.;

lateral, 7.5 mm.

The medullary canal is full. No trabeculae and no cancellous

bone.

Structure. 1. Around the outside of the bone is a ring of

external circumferential lamellae, sixteen to twenty-one in number,

separating into four laminae in the inner and outer walls. The

laminae are interrupted here and there by Haversian systems. As

the ring approaches the posterior middle line it narrows to three or

four lamellae, which gradually merge into the Haversian systems of

that region. Shortly after leaving the anterior mid-line of the

section, in the inner and outer walls, the external ring is re-enforced

by other lamellae, beginning higher in the inner wall than in the

outer and increasing in thickness. On each side, from two or three

lamellae to five or six laminae interrupted by Haversian systems

and forming with the external ring, three-fourths of the whole

thickness of the walls of the bone. As the laminae approach the

posterior wall they change to Haversian systems, which occupy the

whole thickness of the wall, with the exception of a narrow ring of

internal circumferential lamellae. The lacunae of the laminae and

lamellae are long and narrow and their canaliculi are branching.

The laminae are composed of four to eight lamellae with long central

canals, which are gradually rolled into Haversian systems of an

incomplete nature.

2. A crescent of well-developed Haversian systems, thick in

the anterior wall, is situated underneath the external lamellar ring.

The systems gradually merge into the posterior group of Haversian

systems. They are well developed and have two to five distinct,

concentric lamellae, with long lacunae and branching canaliculi.

Their Haversian canals frequently unite.

3. A ring of internal circumferential lamellae, thinnest in the

posterior wall and gradually increasing in thickness until it expands

into six laminae in the mid-line of the anterior wall. The lamellar

and laminar lacunae are long and narrow and their canaliculi are

HISTOLOGY OF FEMORAL BONES I2I

branching. Many large canals pass from the medullary canal into

the interior of the bone and communicate with the canals of the

laminae and Haversian systems.

The bone is of the mixed type. The peculiar features are the

external and internal lamellae expanding into laminae and Haversian

systems.

Femur of the Dog.

PRGV ES Bigs $38)

Antero-posterior diameter of the bone is 14 mm.; lateral, 13 mm.

Antero-posterior diameter of the medullary canal, 9 mm.;

lateral, 7 mm.

The bone is nearly round; medullary canal is full; no trabecule

and no cancellous bone. It is of medium hardness. This femur

shows different arrangements of lamellz, lamine and Haversian

systems in different parts of the section.

For descriptive purposes, it will be better to divide the section

into imaginary fourths, beginning with the posterior mid line and

proceeding around the section to the left or inner wall of the femur.

Structure. First fourth of inner wall—This portion is com-

posed of the following alternating structures:

I. External circumferential lamellz, narrow ring.

2. Irregular Haversian systems.

3. Lamelle (narrow) or lamina.

4. Haversian systems.

5. Lamellz or lamina.

6. Haversian systems.

7. Internal circumferential lamelle.

Second fourth of inner wall:

1. External cimcumferential laminze forming one half of

the entire thickness of the wall.

2. Haversian systems, regular in shape, wide.

3. Internal circumferential lamelle.

Third and fourth fourths of outer wall. These two fourths

have the same structure:

1. External circumferential lamelle.

2. A very wide semicircular band of well-developed Hay-

ersian systems.

3. Internal circumferential lamelle.

122 J. S. FOOTE, M. D.

The lamellae, laminae and systems are well developed. The

lacunae are long and narrow or oval, their canaliculi are long and

branching or short and bushy. The Haversian canals communicate

freely and wide, prominent canals pass from medullary canal to

canals between the laminae. The bone is of the complete mixed type.

The peculiar feature of this femur is the decidedly complex arrange-

ment of tis structural units. The outer wall is not at all like the inner

wall. The posterior fourth of the inner wall is not like the anterior

fourth of the same wall. From a study of structural positions in

other femurs, it appears that the particular situation of any structure

depends upon its muscular attachments or stress. Wherever mus-

cular stress is greatest, there the Haversian systems are best de-

veloped and most numerous, and the laminae are either absent or

incomplete. Wherever muscular stress is least, there laminae or

lamellae are well developed and the Haversian systems are absent,

or few and incompletely formed. Viewed from this viewpoint, the

femur of the dog must be subject to various stresses not apparent

in many other quadrupeds. If the structure does not depend upon

the requirements present, there is no apparent reason for this com-

plex arrangement.

Femur of the Elk.

Pl Vi Figs 30:

Antero-posterior diameter of the bone, 35 mm.; lateral, 33 mm.

Antero-posterior diameter of the medullary canal, 23 mm.;

lateral, 20 mm.

The medullary canal is full. There are no trabecule and no

cancellous bone. The bone is brittle and of medium hardness.

Structure. A wide ring of external circumferential lamellae,

14-40 in number, surround the bone. The lamellae are distinct, their

lacunae are long and narrow and their canaliculi are long and branch

ing. The ring is widest in the anterior inner, lateral wall, where

it is divided into two portions by a canal and by different arrange-

ments of the lamellae. The central ring, constituting the greater part

of the bone, consists of fully-developed laminae separated by con-

centric canals and interrupted at short intervals by completely de-

veloped Haversian systems. The laminae are frequently transected

PLATE VI

wall

Whorls of lacunae

anterior wall.

wide ring

of external

lamellae..

Haversian

Inner Systems :....

wall ——

Lamella Internal

laminaed

[ Fig.3

Femur of a weasel, showing

e. 9. Femur of acat Showing wide ring Of

almost Pens Lamellar typ FU Ste fomellne atregular ying of Haverstan

Femur of awild cat Showing systems and internal laminae.

Uuuy the pecultay avrangement of

mh the Structural units.

— aan

ere

anterior anterioy wall

a iit

Fig. 3b

Femuy of a small grey fox

Showtng the peculiar arrangement

Fig.3

of lamellae, Laminae and HaverStan Femur of a dog acute

Systems ee Ae 37 alteynating laminae Gnel Haverstan

if ‘

A eMhus ofatne wolf showing lamellae, of the inney wall and wide band of

st q

well deve oped. and laminae Havergian Systems of Outer wall

HISTOLOGY OF FEMORAL BONES 123

by the canals, which freely communicate with each other. They are

composed of 5-10-12 lamellae, with long, narrow lacunae and branch-

ing canaliculi. They have the appearance of a strong development.

The canals are wide and in some places have widened into Haversian

systems.

The Haversian systems have 3-9 lamellae, long, narrow lacunae

and long branching canaliculi. The Haversian canals are large,

round or oval in shape, and freely communicate with each other.

There are no incomplete systems in the bone; in fact, there are no

incomplete bone structures of any kind. There are more Haversian

systems in the outer wall than elsewhere. Beginning at the mid-line

of the posterior wall and extending around the outer wall nearly to

the anterior mid-line, and occupying a position next to the internal

circumferential lamellae, a zone of Haversian systems, three or four

in thickness, surround the medullary canal. Their lacunae and

canaliculi are completely formed.

In the anterior wall and near the medullary canal are five or

six large vascular canals, surrounded by 3-4 lamellae. The bone is

of a mixed type, completely developed, with the laminar type pre-

dominating.

The peculiar features are the complete development of all the

bone structures and their arrangemnt. Th bone is more advanced

than that of the deer.

Femur of a Deer (white tailed).

Pl. VII, Fig. 40.

Antero-posterior diameter of the bone, 25 mm.; lateral, 24 mm.

Antero-posterior diameter of the medullary canal, 17 mm.;

lateral, 16.5 mm.

The medullary canal is full. No trabecula and no cancellous

bone are present. The bone is hard.

Structure. The bone consists almost entirely of laminae, which

vary in number in the different walls. The anterior-inner-lateral

wall is thickest and shows 31-33 laminae, the anterior-middle wall

has 26-27, the outer-mid-lateral wall has 17-18 and the posterior

lateral walls 16-17. The laminae are well developed, separated and

124 J. S. FOOTE, M. D.

crossed by wide canals and are composed of three to six or eight

lamellae. Their lacunae are long, narrow and completely developed.

The canaliculi are long and branching. Here and there are found

a few scattered incomplete Haversian systems produced by a circular

widening of the concentric canals and the bending of a few lamellae

around the circular opening. The laminae form the entire section,

excepting that of the posterior ridge, which is composed of Haver-

sian systems and have a general concentric arrangement. There are

no distinct external circumferential lamellae. In the external half

of the section the laminae are arranged concentrically around the

entire bone, excepting at the posterior ridge. In the internal half

of the anterior, inner, and posterior-inner-lateral walls the laminae

are arranged in concentric arcs of circles of shorter diameters, be-

ginning and ending in the internal circumferential laminae.

By this arrangement the internal circumferential laminae are

very distinctly marked off in this region. In the outer wall the

internal laminae disappear and a regular concentric laminar arrange-

ment occupies the whole thickness of the wall. The canals between

the laminae cross them at all angles and communicate freely with

each other.

The internal circumferential laminae form an irregularly-

shaped boundary of the medullary canal only on the anterior-inner-

lateral and posterior walls. They are two or three in number and

are frequently crossed by canals extending outward from the medul-

lary canal. The surface of the posterior ridge shows the tendon at-

tachments of muscles. Extending from this surface to the internal

circumferential laminae, and for a short distance on either side of

the posterior mid-line, is the one area of Haversian systems. They

are irregular in shape, well-developed, for the most part, and by

their position indicate their importance in the valuation of muscular

stress. Their lacunae are long and narrow, generally. A few, how-

ever, show round or oval lacunae, with short, bushy canaliculi. These

form the weaker spots of the bone.

The peculiar features of this bone are its almost complete

laminar structure, its one area of Haversian systems and its associ-

ation in type with the pig and turkeys. These animals appear to be

Antari

Vascula

utar wal,

“4

PLATE Vil

Antarior wall

<TH,

sibel

AAA

Ane:

Outer wall __(

Fig.39.

Left Femur of an EIK showing full

developed Haversian systems , laminae

and Theunae. ¥ ae , ldmellae.,

HISTOLOGY OF FEMORAL BONES 125

widely separated, if we judge from their appearances and habits, but

their femurs certainly belong to the same class.

Femur of a Horse.

PI Vill) Pig: 40

Antero-posterior diameter of the bone, 41.5 mm.;_ lateral,

57.5 mm.

Antero-posterior diameter of medullary canal, 22.5; lateral,

32 mm.

Medullary canal is full. Spongy bone surrounds the medullary

canal and is thickest in the outer wall.

Structure. The anterior, outer, posterior and inner walls may

be considered separately, as they differ in structure.

Anterior wall: The bone has the form of a blunt triangle, with

the longer side as the anterior wall. This wall is composed of well-

developed Haversian systems, with little or no inter-Haversian struc-

ture, excepting a few laminae, some distance from the surface, ex-

tending toward the outer angle. The laminae are interrupted by a

few Haversian systems. The external circumferential lamellae are

generally absent. The Haversian systems reach the external bound-

ary and in some places half systems are present with their Haversian

canals directly underneath the periosteum. The Haversian systems

vary in diameter, are well developed and have three to five or six

concentric lamellae. Their lecunae are long and their canaliculi are

long and branching. In the internal half of the wall a few well-

developed laminae appear with afew Haversian systems. The

laminae are composed of six or seven lamellae and are separated by

canals from which extend short transverse canals. Around the

medullary canal is a thin ring of internal circumferential lamellae,

arranged in the form of cancellous bone.

Outer wall: In the outer wall the external circumferential

lamellae are absent, the Haversian systems and half systems form-

ing the external boundary as they do in the anterior wall. Com-

mencing in the outer, lateral, posterior region a few laminae appear,

which increase in number until they form four-fifths of the thick-

ness of the posterior wall. The laminae are well developed and in-

126 J. S. FOOTE, M. D.

terrupted by frequent Haversian systems. The deeper portion of

the wall is composed of Haversian systems. Around the medullary

canal of this wall the cancellous bone is very much thicker, while the

internal circumferential lamellae are extended from the anterior wall

with the same number of lamellae.

The posterior wall: This wall is composed of well-developed

laminae in the outer portion and Haversian systems, extending from

the circumference to the internal circumferential lamellae, in the

central or angular portion. Underneath the laminae are a few rows

of Haversian systems. Cancellous bone surrounds the medullary

canal of this wall.

The inner wall: This wall has several external laminae directly

underneath the periosteum. Each lamina is frequently interrupted

by Haversian systems. Underneath the lamina are a few layers of

large Haversian systems, and still lower down in the section a few

more laminae are found. Underneath these laminae are a few layers

of Haversian systems, and around the medullary canal are the

internal circumferential lamellae, in the form of cancellous bone and

lamellae. The bone is hard.

The type is well-developed Haversian system and lamina type.

The peculiar features of the bone are the well-developed Haversian

system and laminae. The bone belongs to a high order.

Femur of the Pig.

PLVit tie 42:

Antero-posterior diameter of bone, 21.5 mm.; lateral, 18.5 mm.

Antero-posterior diameter of medullary canal, 16.5 mm. ; lateral,

12.5 mm.

Medullary canal is full. No trabecule. No cancellous bone.

bone is of medium hardness.

Structure. 1. Around the outside of the bone, no lamellae

are present, excepting in the form of laminae.

2. The entire bone, with the exception of the posterior wall,

ic composed of seventeen to thirty-five concentric laminae. The

laminae are separated and crossed by wide canals which frequently

communicate with each other. The separating canals, here and

there, widen into circular spaces surrounded by incompletely-

HISTOLOGY OF FEMORAL BONES 127

developed concentric lamellae which form incomplete Haversian

systems. Interrupting the laminae of the inner portion of the outer

wall are a few Haversian systems. The laminae are long or short

and strongly developed. They have long, narrow lacunae and

branching canaliculi. The posterior wall, for a short distance on

both sides of the middle line, is composed of Haversian systems

well developed. These are the only regular systems of the section.

3. Around the medullary canal are laminae which form a part

of the wall. The bone is decidedly of the laminar type.

Femur of the Ox.

Pl, VIN, Fig.'43.

Antero-posterior diameter of the bone, 44 mm. ; lateral, 39 mm.

Antero-posterior diameter of medullary canal, 23 mm. ; lateral,

21 mm.

Medullary canal is full. No trabecule and no cancellous bone.

Structure. The bone is composed of three wide concentric

rings with irregular boundaries, separated by canals containing

chains of black, lacunar-like bodies with connecting and very irreg-

ular lateral, canalicular extensions. In thin sections there appear to

be no uniting structures in the canals of sufficient importance to hold

the rings together. The outside ring is further partially divided by

an incomplete central canal of similar nature. The canals have an

undulating course and communicate with other canals of the rings.

Outer or first ring: In some portions there are a few external

circumferential lamellae but generally the ring is composed of sixteen

to 20 concentric laminae divided into short lengths. The direction of

the laminae is parallel with the circumference of the bone. Occas-

ionally a few Haversian systems interrupt the laminae, as though

evolved from them. In the anterior wall, which projects pointedly,

the laminae are broken up into irregular Haversian systems which

have their best development in the middle portion of the anterior

wall. The laminae have six to ten lamellae, with long or oval

lacunae and branching or bushy canaliculi folded in some locations

into crude Haversian systems. Some laminae are solid, some have

central canals and some show these canals enlarged at intervals with

128 J. S. FOOTE, M. D.

the lamellae bending around the enlargements, forming Haversian

systems. In this manner lamellae become laminae and laminae,

systems.

Second ring: The borders of the separating canals are com-

posed of clear lamellae, with no visible canaliculi. The second ring

consists of short and long laminae arranged vertically to the outer

ring, especially in the inner wall. Along the outer border of the

separating canal the lamina is concentric. As it approaches the

anterior projecting wall it merges into the irregular Haversian sys-

tems of that region. In the outer wall the laminae are much more

concentric. The laminae of this ring are folded around canalicular

expansions into large elliptical or elongated angular Haversian sys-

tems. As they approach the third ring they are more circular. Their

lacunae and canaliculi are like those of the outer ring.

Third ring: This is composed of vertical and concentric

laminae, of an Haversian system character, intricately intermixed.

There are more systems in the posterior wall. Here they are best

developed. But on the whole, the laminar systems of this ring present

a great variety of forms running in various directions and form a

complex arrangement of structural units. In the anterior projecting

wall the ring merges into the systems of that region. The lacunae and

canaliculi of this ring are like those of the outer rings. The anterior

bluntly-pointed wall of the bone is composed of irregularly-shaped,

large crude Haversian systems united by short lamellae. They have

individual lamellae, large oval lacunae and many thick bushy canal-

iculi. Aroung the medullary canal is an irregular ring of internal cir-

cumferential lamellae composed of three to fifteen lamellae and hav-

ing long, narrow lacunae, with branching canaliculi.

The bone is of the mixed type, the laminar formation predom-

inating. The peculiar features are the three rings of concentric and

vertical laminar systems.

Femur of the Sheep.

Pl, VIII, Fig. 44.

Antero-posterior diameter of the bone, 14 mm.; lateral, 18 mm.

Antero-posterior diameter of the medullary canal, 7 mm.;

lateral, 10.5 mm.

ant

out

Lay

lavers

ry otey

ostert

i7 to 3

ami ni

nmcom

Sy St ry

ryouné

videne

Cana(

wail...

outer wall

Cancellous

bono... .-

Laminaé....

HaverStan

Systems of

posterior Wall

17 to 35

lami nae

Left

of Lae

Incomplete

system

around

widened Canal

Canal

¥ig.42

Femuy o TQ Showin l r

type of stare oe gaa

PLATE VITI

Fig.45.

Haverstan System formed by

filling up meshes or Channels.

Anterio)

wall

(Seva | —

Canat

Third Ying...

Internat

lamellae...

emur of a horse Showing the arrangement

developed Haveysian Systems and laminae

Fig.4b.

a stems formed by bend-

lame

central Canals,

Fiyst ving.

Second ring

Fig-43.

Femur te OX Showing the three rings the

Sepayating Canals. laminae,and Systems

—_—

Internal

Circumferential

laminaeana

lamellae

obli ue

Lamin@e...

Crescent

shafed region

of Haversian

Systems...

External

Gircu m ferential

lameilae of

varyin

thicknesses

Fig.4-4

Section Bf the fermi of a Shee

owing Lameéliae, laminae and Haversian

Systems in irregular arrangement.

HISTOLOGY OF FEMORAL BONES 129

The bone is widest laterally. Medullary canal is full, no trabec-

ule, nor cancellous bone. The walls are thick. The bone is hard.

Structure. The arrangement of the structural units of this

femur is complicated. 1. External circumferential lamellae, six or

seven in number in some places, increasing to twenty-four or twenty-

eight laminae in other portions. The lacunae are long and narrow,

with long, branching canaliculi. 2. Between the external and in-

ternal circumferential lamellae are small and large Haversian sys-

tems, arranged in the form of a crescent, the horns of which begin

and end near the anterior boundary of the medullary canal. The

thickest portion of the crescent is along the posterior ridge. The

systems are, for the most part, small, close together, and their Haver-

sian canals frequently unite. They have few lacunae and few

bushy canaliculi. The outer wall of the bone is composed almost

entirely of laminae, there being a few Haversian systems close to

the internal circumferential lamellae. The laminae are separated

by wide canals, which frequently cross and unite with other canals.

Each lamina is composed of three to five or six lamellae with oval

lacunae and bushy canaliculi. The inner wall of the bone has oblique

laminae and near the anterior surface are found very oblong Haver-

sian systems which appear like circular systems flattened. 3. In-

ternal circumferential lamellae in one or two laminae arranged

around the medullary canal.

The bone exhibits the laminar type of structure as much as the

Haversian system type. The peculiar features of the bone are the

crescent of Haversian systems, the concentric laminae of the outer

wall, the oblique laminae of the inner wall and the flattened systems.

It is difficult to understand the requirements which demand such a

variation in structural arrangement.

Femur of a Squirrel (large Red).

Pl. 1X,-Fig: 50:

Antero-posterior diameter of bone, 4.5 mm.; lateral, 6 mm.

Antero-posterior diameter of the medullary canal, 3.5 mm.;

lateral, 5 mm.

The medullary canal is full. There are no trabecule and no

cancellous bone. The bone is of medium hardness.

130 J. S. FOOTE, M. D.

Structure. External circumferential lamellae, three to twenty

in number, surround the bone. In the posterior and outer walls there

are only three. Beginning in the posterior wall and extending around

the inner wall they gradually increase to twenty as they reach the

inner ridge. They then decrease to three or four as they approach

the anterior wall and then increase again to twelve or fifteen in the

outer anterior lateral wall. In this manner they form an enclosing

ring of varying thickness. Their lacunae are mostly long and

narrow and their canaliculi are numerous, long and branching.

A middle, irregularly-shaped ring of complete and incomplete

Haversian systems is situated under the external lamellae. It is of

varying widths. In the anterior wall it is extremely thin, consisting

of a few round and oval lacunae, with short, bushy canaliculi having

more or less of a circular arrangement. It increases in thickness

around the inner, posterior and outer walls, approaching the ex-

ternal surface and reaches the surface in the outer wall. It thus

forms an uneven ring and occupies an irregular position. It con-

sists of incomplete and complete Haversian systems. In many places

in the inner wall they are composed of oval lacunae with short, bushy

canaliculi arranged in a circular manner and have no central canal.

They are very incomplete. In the outer and posterior walls they

are best developed. Here they have long, narrow lacunae and long

and very numerous canaliculi.

Internal circumferential lamellae form an uneven, thick ring

around the medullary canal. In the inner wall, opposite the ridge,

there are six or eight. They here form the thinnest portion of the

ring. From this point they increase to 20-22 in the posterior wall,

then decrease to 10 or 12 in the outer wall and then increase to

25 or 30 in the anterior wall. Their lacunae are long and narrow

and their canaliculi are long, numerous and branching. They are

fully developed. The bone, therefore, is composed of three very

uneven and irregularly-shaped rings of structural units. The

lamellae are fully developed, the Haversian systems are poorly de-

veloped. The type is lamellar. The peculiar features of the bone

are the uneven rings, the complete lamellae and incomplete Haver-

sian systems.

HISTOLOGY OF FEMORAL BONES I3I

Femur of the Goat.

PLEX Figes7.

Antero-posterior diameter of the bone, 4.5 mm.; lateral, 5 mm.

Antero-posterior diameter of medullary canal, 2.5 mm.; lateral,

3 mm.

The medullary canal is full. No trabeculae. No cancellous

bone. The bone is hard. .

Structure. The structures from without inward are as follows:

1. External circumferential lamellae, six to sixteen in number,

encircle the bone. Of these, six or eight form the inner and outer

boundaries of the inner and outer walls, and twelve to sixteen form

the boundaries of the anterior and posterior walls.

2. Two or three thick laminae, separated in the middle by long,

short and irregularly-shaped Haversian systems. They are thickest

in the inner wall.

3. A thick ring of irregularly-shaped Haversian systems, best

developed in the outer and posterior walls. They are displaced by

laminae in the inner and anterior walls. The systems, in cross

section, are circular, elongated or angulated. Their lacunae are

long and narrow and their canaliculi are long and branching.

4. An irregularly-shaped ring of varying widths composed of

well-developed Haversian systems.

5. Internal circumferential lamellae, four to fifteen in number.

The peculiar features of the bone are arrangements of the laminae

and Haversian systems. The bone is of mixed type.

Femur of a Monkey (Macacus rhesus).

Pl De Bigs 52:

Antero-posterior diameter of bone, 8 mm.; lateral, 8.5 mm.

Antero-posterior diameter of the medullary canal, 5 mm.;

lateral, 5.5 mm.

The medullary canal is full. There are no trabecule. The bone

is of medium hardness. No cancellous bone.

Structure. There are no external and internal circumferential

lamellae distinct from the central ring of the bone, but the following

parts constitute the structure of the whole:

132 J. S. FOOTE, M. D.

A crescent of well-developed Haversian systems, bordering

upon the inner wall of the medullary canal, begins in the posterior

region and extends around the inner and anterior walls to the outer

wall, where it merges into the lamellar structure. The widest part

of the crescent forms about one-third of the entire thickness of the

inner wall.

The systems are fully developed. In several places a half

system borders the medullary canal. The lacunae are long and

narrow and their canaliculi are long and branching. The Haversian

systems are united by short inter-Haversian lamellae. A second

crescent of Haversian systems borders the medullary canal extend-

ing from the posterior prominence around the posterior and outer

walls to about the middle portion of the outer wall. The systems

of the two crescents are the only fully developed systems present.

The second crescent is narrower than the first. Its widest part 1s

in the posterior region of the outer wall. The lacunae are long and

narrow.

The main structure of the inner, anterior and outer walls is

lamellar. It consists of irregularly concentric lamellae, interrupted

by rudimentary Haversian systems. They are not clearly distinct

and not easily followed for any distance. In some places they assume

a fan shape, as though on their way to Haversian systems. This

lamellar structure makes up two-thirds of the whole bone and sets

the type as lamellar. The lacunae are generally long, wider than

fully developed lacunae, and have long, branching and numerous

canaliculi. In some places the lacunae are curved and quite irregular

in shape. The Haversian systems are not clear. Their outlines are

not traceable. They consist of Haversian canals, from which radiate

fine canaliculi, extending into the surrounding lacunae. The systems

are very low in development. The posterior wall and ridge consist

of Haversian systems poorly developed. They are separated by

lamellae. Their outlines are not sharply defined, but appear to merge

into the surrounding lamellae. Their lacunae are narrow and oval.

The type of bone is lamellar, incomplete. The peculiar feature of

the bone is its low development among mammals.

HISTOLOGY OF FEMORAL BONES 133

Femur of Man.

PLOiXk Figs

Antero-posterior diameter of the bone, 28 mm.; lateral, 30 mm.

Antero-posterior diameter of medullary canal, 16 mm.; lateral,

17 mm.

Medullary canal is full, no trabeculz, cancellous bone present

around medullary canal; compact bone encloses the cancellous and

forms greater part of the wall. The bone is of medium hardness.

The type is Haversian system. The medullary canal is large and the

walls of the bone are thick.

Structure. Around the outside the external circumferential

lamellae appear only at scattered points. Here and there a few

lamellae occupy the outer boundary for short distances. Judging

from their irregularity and poor development, they are apparently

unimportant. Their lacunae are long and narrow and their canaliculi

are long and numerous. The whole compact bone is composed of

Haversian systems. They extend from the inner cancellous bone to the

very circumference of the shaft and in some places the most external

systems are only half systems. They are rather small, somewhat

irregular in size and shape. In some regions they are close together,

in others they are separated by short lamellae or laminae. Their

lacunae are long and narrow and their canaliculi are long and

branching. Their Haversian canals communicate with each other

and their concentric lamellae are distinct. Around the medullary

canal is 4 ring of cancellous bone extending nearer to the anterior

external surface than to the posterior. The marrow spaces com-

municate with the medullary canal. The internal circumferential

lamellae, poorly marked, form the inner, irregular layer of the

cancellous bone. Lamellae and laminae, however, are insignificant

as structural units; the type of structure is decidedly Haversian

system. The human femur differs from all others studied.

SUMMARY.

1.—Three Types of Structure:

Although the number of fumurs examined is not yet large, it

ts large enough to indicate three types of bone structure, viz:

134 J. S. FOOTE, M. D.

the lamellar, laminar and Haversian system types. These may occur

pure, or mixed.

The lamellar type is composed of several lamellae of bone, com-

pletely or incompletely developed, concentrically arranged around

the medullary canal, as in the femur of the frog (Pl. I, Fig. 1).

The laminar type is composed of several laminae of bone, com-

pletely or incompletely developed, concentrically arranged around the

medullary canal, as in the turkey, pig, deer and peahen (PI. ITI, Figs.

13, 15; Pl. VIII, Fig. 42). Each lamina consists of several lamellae

and is separated from adjacent laminae by canals.

The Haversian system type is composed of Haversian systems

generally running parallel with the external and internal surfaces

of the wall of the bone. The systems may be large or small, regular

or irregular in shape, held together by lamellae or laminae, and en-

closed or not enclosed by external and internal circumferential

lamellae or laminae, as in the femur of man (PI. IX, Fig. 53).

The femurs of other animals are made up of various com-

binations of these types, arranged according to the stress require-

ments of each. The three types of structure are present in the

femurs of many animals, but the proportions, positions, develop-

ments and arrangements of these structures vary greatly in all.

Lamellae and laminae characterize the larger number of femurs and

are usually completely developed.

A study of these bones shows a great diversity of structural

units and arrangements and wide differences in the shapes of femurs,

thickness and hardness of their walls and in the character of their

contents. Some are practically round, as the frog, turtle, crow,

domestic chicken and skunk. In some bones the antero-posterior

diameters are the longest, as in the wild goose, dog, pig, wolf, wild

cat and ox. In some the lateral diameters are the longest, as in the

alligator, wild turkey, domestic turkey, man, mallard duck, peahen,

woodchuck, rabbit, sheep, cat, raccoon, muskrat and opossum. The

walls vary in thickness. The peahen has the thinnest walls and the

turtle the thickest.

The contents of the medullary canals vary. They are empty in

the mallard duck, peahen, prairie dog, muskrat, and full in the frog,

turtle, alligator, wild turkey, domestic turkey, man, wild goose, crow,

HISTOLOGY OF FEMORAL BONES 135

domestic chicken, wood chuck, dog, owl, rabbit, sheep, pig, cat,

skunk, raccoon, mink, opossum, wolf (timber), ox and goat. Two

have medullary trabeculae: peahen and muskrat. Three have circum-

medullary cancellous bone: turtle, man and alligator. The bones

of the turtle, alligator, peahen, owl, sheep, goat, wild cat, ox and

man are hard; those of the wild turkey, domestic turkey, crow,

prairie dog, woodchuck, rabbit, muskrat, fox and opossum are soft,

and those of the wild goose, mallard duck, domestic chicken, dog,

pig, skunk, raccoon, mink and wolf are medium.

Haversian systems are best developed in man, horse, dog, elk,

sheep, wolf and ox. They are incomplete in the turtle, alligator,

mallard duck, crow, domestic chicken, owl, muskrat, opossum and

prairie dog.

Laminae are best developed in the pig, deer and elk, incom-

pletely developed in the turkey, peahen, wild goose, mallard duck,

owl and muskrat. They are well developed as partial structures in

the horse, ox, wolf, woodchuck, dog, rabbit, sheep and raccoon.

They are absent in the chicken, skunk, mink and opossum. They are

oblique in the sheep and rabbit.

The external circumferential lamellae are widest and best de-

veloped in the prairie dog, wild cat, cat, skunk, raccoon, muskrat,

mink and wolf; the internal lamellae, in the owl, opossum and ox.

Anterior walls are unlike posterior; outer, unlike inner walls.

Posterior ridges have best developed Haversian systems.

Nearly all femurs have two forms of lacunae and canaliculi,

long and narrow, with long, branching canaliculi, and round or oval,

with bushy canaliculi. The oval or round lacunae with bushy

canaliculi belong to incomplete developments, the long to the

complete.

2.—The Formation of Haversian Systems (Pls. VIII, Figs. 45, 46;

Pl. IX ,Figs. 47, 49):

Haversian systems appear to be formed in three ways:

1. By the concentric arrangement of round lacunae, with short,

bushy canaliculi, around the central canal (Pl. IX, Fig. 47). The

lacunae increase in number and the foreshadowed system increases

136 J. S. FOOTE, M. D.

in diameter (Pl. IX, Fig. 47). These forms are found in reptile

femurs: turtle and alligator. The round lacunae then become oval

and their canaliculi are less bushy (Pl. IX, Fig. 47). This form

may be seen in some birds and low mammals; turkey, opossum.

Then the lacunae, by pressure of development, ‘apparently become

narrow and long, with long, single or slightly branching canaliculi,

as in man and the higher mammals. This method of formation is

fundamental in bone developments and seems to show a phylogenetic

history.

2. By the concentric arrangement of lamellae around the inside

of channel walls or cancellous meshes, as in bone repair or ontogen-

etic development (Pl. VIII, Fig. 45).

3. By the separation of lamellae at definite points and bending

of the lamellae around a central canal, as may be seen in the pig

(Fig. 42 and in Fig. 49). As the lamellae and laminae are the

first bone units to appear, their lacunae are the first to become long

and narrow.

The Haversian system development appears to be much later

and therefore in many animals both incomplete and complete forms

are found, the predominating character of the system indicating the

degree of development present in any animal.

3.—Some General Principles:

In working out the comparative histology of femurs, the writer

is conscious of the fact that the number of bones examined may not

be large enough to warrant the following generalizations. However,

they are presented subject to correction as future studies may

suggest:

1. The structural units of femurs are lamellae, laminae and

Haversian systems, and establish the three types of bone.

2. They may be developed or incompletely developed.

3. The characters of these units are indicators of the positions

which animals occupy in the scale of graded development.

4. The units display the species, type and individual develop-

ment by their variations in the architectural plan and the complete-

ness of their formation.

5. They exhibit evidences of phylogenesis.

HISTOLOGY OF FEMORAL BONES 37,

6. They show structural responses to functional demands.

7. Cancellous bone usually shows a higher state of complete-

ness than compact bone, and indicates by its position around the

medullary canal an older formation.

The first units to appear were the lamellae, with their enclosed

lacunae and canaliculi. Since they are layers of bone substance, they

were, of necessity, produced as soon as animal mass required a

skeleton.

The completeness or incompleteness of the lamellae depend

upon the pressure developments arising from the applied forces of

environing conditions, as indicated by round and oval lacunae, with

short, bushy canaliculi and long, narrow lacunae with long, branch-

ing canaliculi.

Gradations are based upon three factors which characterize the

bone:

1. The time of its appearance in vertebrate history.

2. The predominating completeness or incompleteness of the

elements which constitute its structural units.

3. The architectural plan which is present.

Thus three general grades of femurs may be recognized with

which all developments are compared:

1. The lowest grade appeared first in the amphibian. It con-

sists of single units, lamellae, unevenly developed and exhibits one

plan of arrangement. Such a bone is the femur of the frog.

2. The next grade—transitional—first appeared incompletely

in the reptile. It consists of laminae and exhibits one plan of ar-

rangement. The laminae are formed by grouping and separating

the lamellae by canals. Such bones may be seen in the turtle, alli-

gator.

3. The third and highest grade appeared, in outline, in the

reptile and in more complete form in birds and mammals. It consists

of Haversian systems, completely developed in mammals, and ex-

hibits a definite plan of arrangement. Such bones may be seen, in

their best form, in the femurs of the horse, man, ox, goat.

No femur shows a complete development of all of the elements

of its structural units. Bones vary greatly in this respect. Some

are mere outlines ; some show lamellae and laminae well developed,

138 J. S. FOOTE, M. D.

and Haversian systems poorly developed. But, in all cases where the

Haversian systems are well developed, the lamellae and laminae are

also. That is, the Haversian systems are the last to develop, and

therefore belong to the highest classes of mammals. The position

which an animal occupies in the scale of development is, therefore,

indicated in part by the character of its bone units.

4. Lacunae and Canaliculi an Index of Development (Pl. IX,

Fig. 48) :

The state of development of lamellae, laminae and Haversian

systems is indicated by the characters of their lacunae and canaliculi.

Wherever these elements are round or oval and their canaliculi are

short, bushy and rather infrequent, the state of development is low;

wherever the lacunae are long and narrow and have long, branching

numerous canaliculi, the state of development is high.

The bone of the frog has a majority of oval lacunae with bushy

canaliculi, and is therefore poorly developed. Furthermore, since it

has only one unit (lamellae) it is low, comparatively. The bones of

the turtle and alligator have a majority of round lacunae with short,

bushy canaliculi, and are low in development, but they show the

three units and plan of arrangement and are higher than the frog.

The bones of the turkeys, peacock and eagle have predominating

oval lacunae with short canaliculi and incomplete Haversian systems.

They are low in development. But since they all show the laminar

formation, they are higher than the reptiles.

The bones of the wild goose, domestic chicken, prairie chicken,

mallard duck, have predominating oval lacunae and are low in de-

velopment, but high in arrangement.

5.—The Grade of Bone is Further Determined by the Development

of Its Haversian Systems. For example:

The bones of the owl, crow, pelican, hawk, yellow hammer, blue

jay have high lamellar developments and low Haversian systems.

They are low.

Among mammals the bones of the skunk, opossum, musk rat,

prairie dog, monkey, weasel, rat, mink have high lamellar develop-

HISTOLOGY OF FEMORAL BONES 139

ment and low Haversian system development. They are therefore

low.

The bones of the rabbit, pig, raccoon, woodchuck, domestic cat,

wild cat, dog, fox, goat, wolf, sheep, deer, horse, ox, elk, man have

high lamellar and Haversian system development and are therefore

high.

The development of crude Haversian systems in the reptiles and

the gradual changes which they show through the birds and mam-

mals indicate phylogenesis. No complete systems are found in the

reptiles, a very few in birds, a very few in the lower mammals, while

they show complete development in the higher mammals.

6.—Classification of Femurs:

Arranging the femurs according to their predominating struc-

tures, the following divisions may be made:

I | II | iil | IV | Vv

Incomplete

Lamellar Laminar Mixed Type: Complete Complete Mixed Type:

Type. Type. Lamellar and Haversian Lamellar, Laminar, and

Laminar. System Type |Haversian system type.

Frog, Domestic Man, Sheep,

Cat, Turkey, Dog,

Skunk, Wild Turkey, Woodchuck,

Mink, Pig, Ox,

Raccoon, Peahen, Wolf (Timber),

Musk Rat, Deer, Goat,

Prairie Dog, Eagle, Small grey fox,

Opossum, Grouse, Rabbit,

Rat, Elk.

Wild Cat, Horse,

Blue Jay,

Monkey,

Squirrel,

Weasel,

Yellow-hammer,

Hawk,

Prairie Chicken,

While variation in function may be supposed to account for a

corresponding variation in structure, it scarcely seems that the

femurs of these animals have sufficiently common demands to

associate them as they appear in the above table; nor do the like-

nesses or unlikenesses follow the zoological classification, as will be

seen from examinations of the plates. There is no close relation

between the brain development and activities and the histology of

the femur. For example, the monkey femur does not conform to

the human type. The monkey bone is chiefly lamellar, while the

140 J. S. FOOTE, M. D.

human bone is Haversian system. The monkey is much nearer the

weasel or squirrel than the human in bone structure. The horse, on

the contrary, is quite similar to man in bone development.

7.—Specific versus Functional Features:

The units fix the species type and also show the individual vari-

ations. All animals belonging to a species conform to that type and

yet display the variations which are required by environmental vicissi-

tudes. The femurs of two domestic turkeys, one weighing seventeen

pounds and the other thirty-two pounds, were examined. They were

both laminar, but the heavier turkey had more Haversian systems

and a much thicker and better developed internal circumferential

lamellae. These increases are evidently in the nature of re-enforce-

ments.

Bones thus show in their structure a response to functional de-

mands. This appears in the femurs of the two turkeys cited above.

Doubling the weight called for femur re-enforcements and they

came in an increase of Haversian systems and the thick internal

lamellae.

In order to explain such varieties of structure and arrangement

as have appeared in this study, we are driven to the following

conclusions :

1. That the structural units and their arrangements depend

primarily upon some biological law which governs the entire bone

formation of an animal and which sets the type according to which

all of its bones are constructed.

2. That the structural units and their arrangements depend

also upon the functional requirements and activities of the bone.

3. That structural variations are best accounted for as de-

pendent on the interaction of these two agencies.

The writer desires to thank those who kindly assisted in secur-

ing the femurs, and would be very glad to receive fresh femurs of

animals not included in the above list. The femurs should be fresh,

or the first observer should note the contents of the canal while it is

fresh. Sawed rings of the above femurs will be sent to interested

parties as long as they last.

Creighton Med. Coll., Omaha, Nebr.

PLATE IX

Anteriov wall

Lamellae.,

Early form. Laler. Still later.

Completed.

Laminae... Diaoyams Showin ormation of Haverstan Systems

1p peessure development

Tnner wall

Haverstan ee athe Ridge

SyStems.., _ Ott

Round. Oval. Elongated.

Fig .4- Development

7 : of Lacunae.

Diagram Showing the formation ——________.

Of HaveyStan Systems

External Fiq.5 0.

circumferential

Sie” . ete *

Qntertor wall ——

Squirrel (Laxge Red).

lamellae. Femur of & qe ‘s

Int¢cyna( :

Cicumferential

loemalliien Cancetlous

Rudimentary

Haver Slayr

Systems

antertoy

wall,

Crescent

Tnner wall

Lamellae

Posterior

prom inence

fbr HaverSian

Haversian

; Systems. Systems.

F019. 52 maitiea's

Femuy of a Monkey (Macacus Rhesus), f:9.S4

Femur of a goat showing

Fig 63 pecue Y Grrangement of laminae

3 nd Haverstan systems.

Section of @ human femur-center of shaft

NOTE ON A GROWTH OF SYNURA IN LAKE

COCHITUATE, MASSACHUSETTS.

By Horatio NEWTON PARKER.

In the American Naturalist, Vol. 33, No. 390, Page 485 (1899),

G. C. Whipple and the writer described a growth of Mallomonas

at the thermocline in Lake Cochituate, and later, in a paper ‘‘On the

amount of Oxygen and Carbonic Acid Dissolved in natural waters

and the Effect of These Gases Upon the Occurrence of Microscopic

Organisms” (Trans. Am. Microscopical Soc., Vol. 23, Pages 103-

144, 1901), commented on the growth as follows (Page 140):

“Tt will be seen that the organisms (Mallomonas) were concentrated

just below the thermocline. From what is now known of the dis-

tribution of oxygen and carbonic acid in Lake Cochituate, the reason

for this is at hand. At the surface and throughout the circulating

water above the thermocline oxygen was abundant, but carbonic

acid was absent. Near the bottom of the lake there was carbonic

acid, but no oxygen, and likewise an insufficient amount of light for

plant growth. But just below the thermocline there were both

carbonic acid and oxygen, and as Mallomonas is a chlorophyl bear-

ing organism, it found there favorable conditions for its develop-

ment.”

As being in line with these statements, it is desired to record here

the observations that were made on a growth of Synura in Lake

Cochituate in 1900. At that time the data were not available for

publication, but they are now presented by permission of Dexter

Brackett, Chief Engineer of the Metropolitan Water Board, and

through the courtesy of A. W. Walker, Biologist of the Board.

The noteworthy facts are given in the accompanying table.

0 3)

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9°8F OF j9°SF |0 |8'sh | 0 06 : a

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FPR [SOTO PP |S FF 6'SF | 0 PPP OFF Gtr )O {Ltr 02 oh

USF | OTL SF |8°SF TGF | 0 rah {0 = |9°9F 9°F | OL |a°ct 0 OF

PLP 199°6 |S Lh ELF GOLF | 02 ULF U8F Sl4F);O |ULF 0 cs

SF |S1'6 |8'8h |6°8F 0'6F | 0 P'S | OLL |L°6F | OST |L'6P | OOT |S'8h | OF 083 |L° TS] 96T 929 |9°.FG] 08 |0°.S9} 08

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61S 1°08 xg

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8°19 61

0 |6'09 919 8T

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F°6S | 3S |L'F9 |E'F9 0'F9 | 0 0°89 |}0 = |FTL 0°92 }0 |6°9L 0 a

F'6S | O'S |T'F9 849 | O a'é9 0 jo89|0 |FTL}0 |TeL}0 692] 0 j0°.44) 0 0 |8°.d4) 0 0 |e.9L) 0 |9°.FL Epa:

-ansg

———— — —_ | —__}_ | — | T_T nn | | | | ————— | | — | | -—

cele endlean esate |e cael Geli \obeleec ie lal folea Gel aelba|ecalran| el osaliae lag \egelecy |: al

P(ECHE VE SIE BIELBIEI EVE IE ISL EIEI BIS |EIE LEI EI EIE ETE) BE la.

:0061 ‘SI 19q0}9GQ 0} ‘0061 ‘g ysNSNY WoIZ dJeNYIOD oye] ur syydap jussIyIp ye oT

jod syed ut OD 2041f pue ‘o'o sod sytun prepuejs ut einuds pure yoyuere,y sdoigap ur sinjzerodtu [,

A GROWTH OF SYNURA 143

Synura appeared on August 6th and persisted through Sep-

tember 21st, after which date it was not found, though observations

were continued until October 15th. At no time during the period

was the organism discovered at a depth of less than fifteen feet and,

though the Synura seems to have been scattered from mid-depth to

the bottom, there never were found more than 40 standard units per

¢.¢c. in any sample taken at a depth greater than 30 feet. Between

the depths of 15 and 30 feet Synura thrived, though the position of

most vigorous growth appears to have been clearly defined at

between 25 and 30 feet, for it was at these depths that the largest

numbers were obtained. The temperatures prior to September 7th

were taken with a thermometer and those obtained at 30 and 60 feet

are undoubtedly high; yet they are sufficiently accurate to show that

the lake was thermally stratified. On September 7th, and thereafter,

the temperatures were taken with a thermaphone (The Microscopy

Drinking Water, Whipple, 2d Ed., p. 54) and are accurate. It

appears from the table that during the period the temperature of

the water varied from a maximum of 77°.0 F. at the surface to a

minimum of 43°.3 F. at the bottom, and that while the growth per-

sisted the temperature of the surface to 10 foot stratum, wherein

no Synura was found, was never less than 68°.0 F. The highest

temperature at which a considerable quantity of Synura developed

was 66°.5 F., the temperature of the 15-foot sample on September

7th and the lowest temperature at which the organism was found

was 43°.6 F., the temperature of the 40-foot sample on September

1oth. The temperature of the samples ranged from 48°.5 to 50°.8 F.

at 25 and 30 feet, and, as it was at these depths that the greatest

quantities of Synura were obtained, it may be that within these

narrow limits the organism finds the temperatures that most favors

its development. Temperature is not the only factor, however, that

fostered the organism at this place in the vertical dimension, for at

higher levels there would have been less free carbonic acid and at

lower ones less oxygen and less sunlight, and all of these are essential

to the organism. However, the observations that Synura at no time

during this considerable summer growth was found at a temperature

higher than 66°.5 F. and that it was most numerous at temperatures

between 48°.5 F. and 50°.8 F., accord with the fact that in the colder

144 HORATIO NEWTON PARKER

parts of the year, in late autumn, in winter and in early spring the

organism most often develops in quantities large enough to impart

its characteristic disagreeable odor of ripe cucumbers to large bodies

of water. Moreover, the growth in Lake Cochituate throws light

on those big summer growths of Synura that sometimes unexpectedly

appear in public water supplies, infest them for a few days and

suddenly die out ; for it is quite possible that, as in Lake Cochituate,

the organisms establish themselves in a favorable environment at

a depth in the water and later by a high wind or some other agent

are brought to the surface, where they soon succumb to lack of food

and unfavorable temperature.

In studying this growth of Synura, free carbonic acid determin-

ations ought to have been made, but it was not possible to do this

prior to October 12th, at which date the organisms had entirely dis-

appeared. However, from this single observation and the temper-

atures recorded, together with what is now known of the distribution

of free carbonic acid in Lake Cochituate when it is thermally strat-

ified, it seems reasonable that during the period of this growth of

Synura, the free carbonic acid at 25 feet was about 9 parts per

million, at 15 feet about 5 parts and at less depths, about 2.5 parts.

Of course, in the absence of actual determinations, it is not certain

that the free carbonic acid then was thus distributed, but to the writer

it seems entirely probable that it was so.

What terminated this growth in Lake Cochituate is not apparent.

At the time the Synura disappeared the temperature at 30 feet, where

the growth had been largest, was unchanged (49°.0 F.), and the

supply of free carbonic acid was abundant; the only clue to the

disappearance of the Synura is to be found in the temperature read-

ings, which show that the surface waters were rapidly cooling. It

may be the Synura swam away from its plentiful food supply of

carbonic acid into the circulating cooling waters and thus perished.

Boston, Mass., March, rort.

DEPARTMENT OF SUMMARIES

TOBE DEVOTED TO DIGESTS OF PROGRESS

IN BIOLOGY