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J OAL IN AL

MORPHOLOGY

EDITORIAL BOARD

Epwarp PHEtps ALLIS, JR.
Milwaukee

Epwin G. ConkKLIN
Princeton University

Henry H. DoNALDSON
The Wistar Institute

Mitton J. GREENMAN
The Wistar Institute

Ross G. Harrison
Yale University

G. Cart Huser
University of Michigan

Horace JAYNE
The Wistar Institute

Frank R. LILure
University of Chicago

FRANKLIN P. Mau
Johns Hopkins University

CuHartes S. Minot
Harvard University

Tuomas H. Morcan
Columbia University

GrorcEe H. Parker
Harvard University

CHARLES O. WHITMAN
University of Chicago

Epmunp 13. WILSON
Columbia University

VOIP OCUx

PHI LADELPHI:A

tae wWisl AR INS TILULE OF ANATOMY. ANDY BIOLOGY

CONTENTS. OF: VOL, XIX.

No. 1.—FEBRUARY, 1908.

PAGES.
FRANKLIN P. MALt.
A Study of the Causes Underlying the Origin
of Human Monsters. (Third Contribution
to the Study of the Pathology of Human
EEO EMOG Ni at pers cot ee tame her Ve abe Meta tec thane 3-368
No. 2.—-OcTOBER, 10908.
I. Heten Dean Kine.
The Oodgenesis of Bufo lentiginosus ...... 369-438
Il. Heven Dean Kine.
The Structure and Development of Bidder’s
Organ in Bufo lentiginosus ......... 439-408
Ill. JAcos REIGHARD AND JESSIE PHELPS.
The Development of the Adhesive Organ
and Head Mesoblast of Amia ....... 469-409

IV. JAcosp REIGHARD AND S. O. Mast.
Studies on Ganoid Fishes. IT. The Develop-
ment of the Hypophysis of Amia .... 497-510
V. Roy L. Mooptr.
The Lateral Line System in Extinct Am-
PUVO UGA se gk 5 oe Mme ver ee Ge 511-540
VI. SorsterJ. ANTHON.

The Larva of Ctenophora angustipennis,
1 TUE a Nimes oa Rey eta Oe ET Be Se a 541-560

No. 3.—DECEMBER, 1908.
ArTHUR Day Howarp.
The Visual Cells in Vertebrates, Chiefly in Nec-
CHES HUUCUNOSUS S «< iy tate foes at hs) s Sha sulhewte he 561-62

Volume XIX. February, 1908. Number 1.

|

JOURNAL

OF

MORPHOLOGY.

A STUDY OF THE CAUSES UNDERLYING ‘THE
ORIGIN OF HUMAN MONSTERS. (THIRD
CONTRIBUTION TO THE’ STUDY
OF THE PATHOLOGY OF
HUMAN EMBRYOS.)

By FRANKLIN P. MALL,

ProrEessor oF ANatTomMy, JouNs Hopkins University, BALtimore, Mp.

PAGE
MEO CITC ELOLIMN erecta oacis oo Seca Baum sraceeiaie ws ee Sa alates cleieje'e, bisleuelarefore 2
Part I
lsiaiaareall see cea es Secnoo bem BeBe aoe or ol6 Namo Geiaton doit o amar raatn (a)
Experimental :

(a) Datibles Monster Ssiseke Sede ce + ccieln nie cleans sic ov ole ale « osniely 17
(b) Lithium embryos and nodular forms in chicks and man...... 21

(c) Experiments with salts of potassium and changes especially
TITRE Cleantiertin ey. ecu tae as as ncvenscte etlekorn aus erotocgn ei@isiarsavo.a's) stale 25
(d) Sodium monsters—spina bifida and anencephaly ............ Be

(e) The destruction of tissues in magnesium monsters, cy-
elopia atid club-f00t. - 02 1. ewe Pasi wea e Peele nse seas 43
BapMOlOSICAl GVA. 6 fac oes socio ednin see asias eres At Hon OCP PR ita cOmen 48
REWits PYERUATICICS, vo nec nes ecica's cies vies ae ted oes wees Fetes aewaseeeesss 58

I

2 MALL. {Vor. XIX.

- PAGE
Unruptured tubal pregnancies. .......0..4.0 occ eee cee ede cree ee cen 60
Ruptured tubal pregnancies .......... 6. eee e ence cee cee eee eens 65
Partial or complete destruction of the amnion, leaving only the
mbiliGal ~vesicl@: ja.%5 es eke ea ee ed clone eee erent 69
Ova in which the embryo and amnion have been destroyed, including
certain moles. «.25%iBes chroukte.ee Waichanoe Bae os ott eral ene 82
Pathological ova in which the embryo has been destroyed, leaving a
portion of the umbilical cord and the amnion .............. 90
Pathological embryos sot the second weels {io siemcm tsetse eee 07
Embryos. of. the -thisd! sweek 2 ace hae aicf- caver ate toi iene crete 102
Embryos: of the. founnthy weeksncer\ iso creo osetia bs eee ese ieee 107
Pmbryos'.of (the filthy week craters ca seer ttc chs were emer 113
Exfibryos: of athe sixtle pweekk <tisitictemvessrecni> steve ails & lense ste pestarerne satan seared 118
Embry@sy ofsthe; seventh gweekein jae tise icicle fatate cjaler Soleo ct ane beeeraye rege 12
Embryos of the eighth week and older ....... ORAS SOG oe ee 133
Part i:
Description of. the specimens, and ieticeso, 222 at a diae nuiiecsias Aeveelrr te 139

Mescrmbtiow of themplates sence... tee. ceca icin seetotes- ayaa ene eerie eae ete cae 305

INTRODUCTION.

The present communication is the outcome of a study of
163 pathological human embryos which I have collected
during the past fifteen years. The first contribution! which
I made to this subject included a report of 53, and the second?
of 20 of these embryos. These two studies are rather
anatomical in nature and do not consider the causes which
produce pathological embryos, nor their relation to ordinary
human monsters. A more careful study of my specimens,
which have more than doubled in number during the past five
years, establishes beyond doubt (1) the identity of path-
ological embryos and small monsters, that is, many of them
would have developed into real monsters if they had not been
aborted, and (2) that all of them are developed from normal
ova due to external influences,—in man to a condition which
I shall term faulty implantation.

From the earliest ages in the world’s history the study of
monsters, and the causes which produce them, has been one
of the capital problems in anatomy, medicine and natural
history. Supernatural causes for the production of monsters,
like the influence of the gods, celestial or diabolical, or lunar
influences, as expressed in their name, monster or moon-calf,
held for a long time universal sway and are still believed in
by many ignorant people. However, the Greek naturalists
and physicians were inclined to ascribe them to natural causes,
which belief was gradually displaced in the Dark Ages by the
one that monsters were hybrids of bestial origin, a theory
which was finally overthrown in the eighteenth century.
Equally general has been the theory that maternal impressions
affect the offspring and convert them into monsters. This

*Mall, Welch Festschrift, Johns Hopkins Hospital Reports, IX, 1900.

*Mall, Vaughan Festschrift, Contributions to Medical Research, Ann
Arbor, 1903.

1 3

4 MALL. [Vou XIX.

belief is of great antiquity, and is at present of world-wide
distribution. It also was attacked in the eighteenth century,
first by Blondel from a philosophical and then by Haller from
a scientific standpoint.

All the theories can be resolved into the simple question:
“Are the conditions which produce a monster germinal and
therefore hereditary, or are they produced from normal
germs by external influences?’ The discussion on both sides
of the question has been a long one, conducted during many
years by the ablest masters, among whom are always in-
cluded the leading anatomists of the time. However, the
theory of external influences gradually gained ground during
the nineteenth century, as the science of embryology was
cultivated more and more. But here again we have two
schools, the one believing that monsters are formed from
normal germs due to maternal impressions, the other that
they are due to mechanical influences. It may be noted here
that the obstetricians and gynecologists of America as a class
advocate strongly the theory of maternal impressions, due
largely, no doubt, to their insufficient scientific education.
On the other hand, we may pride ourselves over the masterful
strokes of American teratologists against this theory; the
experimental teratologists have produced double monsters,
spina bifida and cyclopia, under the very noses of these prac-
titioners, but they continue their futile speculations over mere
coincidences.

With Meckel, who laid the embryological foundation for a
scientific teratology, and the Saint-Hilaires, who made the
first teratological experiments, we have the beginning of the
development of the mechanical theory. It appears in a
variety of forms, as, for example, that monsters are due to
tight lacing which causes pressure upon the embryo, or to the
contracting uterus which naturally might have the same effect.
However, this theory was gradually transformed by tera-
tologists so that now it rests upon the idea that amniotic bands
constrict or compress the embryo, thus bringing about its
deformity. Occasionally it has been found that monsters are

No. 1.] ORIGIN OF HUMAN MONSTERS. 5

attached to the chorion through newly-formed bands of tissue,
and such bands, whether present or not, are held responsible
‘for all terata. This coincidence, as I term it, cannot be of
frequent occurrence, for usually there is present an hydram-
nios. Nor can even the “coincidence” occur in anamniotic
animals. Furthermore, no amniotic bands were ever found in
any of the 169 specimens which I have studied.

In place of these theories it is my purpose to demonstrate
that all monsters are produced by external influences upon
normal ova which affect the nutrition of the embryos due to
faulty implantation of the ovum. That the power to become
a monster is present in every ovum is fully demonstrated by
experiments upon a variety of vertebrates as well as by all
of my pathological ova, especially those obtained from tubal
pregnancies.

The changes found repeatedly in the chorion are no doubt
primary; they are usually of an hemorrhagic nature, often
indicating inflammatory changes in the uterus. I shall only
hint at the cause for the changes in the uterus, which may
interfere with the formation of the decidua, and recommend
this field as a very fertile one for gynecologists and obstet-
ricians to investigate. At any rate, the change interferes much
with the attachment of the ovum, and this condition and what
results from it I have termed faulty implantation.

It has been impossible, in fact it is not desirable, to discuss
extensively the immense amount of excellent literature upon
teratology. The whole makes one of the best chapters in
medical literature to which the greatest minds of medicine
have contributed their best efforts. One cannot go through
these writings, many of which are comprehensive, without
laying them aside with profound respect. In this study I
have used many of them freely, but make, however, very few
references.* I have also avoided technical terms as much as

*J. F. Meckel, Handbuch d. pathol. Anatomie, Leipzig, 1812.
Forster, Die Missbildungen des Menschen, Jena, 186s.

Bischoff, Wagner’s Handworterbuch, 1842.

Ahlfeld, Die Missbildungen des Menschen, Leipzig, 1880-1882. Part

6 MALL. [Vo.t. XTX.

possible, and in general have adopted Ballantyne’s classifica-
tion, which, in turn, is based upon Tarufh’s.

I wish it were possible to thank adequately the many
physicians who have contributed the specimens and who have
responded so generously to my many inquiries. All data
obtained from them are given in quotations under the descrip-
tion of the specimens, which are also properly credited to the
donors. Some names will be seen repeatedly, as Miller,
Boldt, Lamb, Brodel, Ballard, West and Minot. In addition,
I wish also to thank my colleagues at the Johns Hopkins,
who have aided me in every possible way to bring together
the gynecological, obstetrical, pathological and experimental
embryological evidence.

In this paper all of the embryos mentioned in the two pre-
vious ones are discussed, and brought together in Part Il.
The essence of the first contribution is given, and all of the
second contribution is incorporated in this publication, so in
a measure it may be viewed as a study of the whole collec-
tion. However, the various steps by which I came to arrange
the specimens, as I have, can be understood only by consulting
the two previous publications.

III, which was to be the important part, never appeared. Fortunately,
however, Ahlfeld’s library, which is very complete, was presented to the
Johns Hopkins University. This I have consulted freely and in a way
it makes up for the missing Part III.

Marchand, Missbildungen, Eulenburg’s Real-Encyclopedia, 3d edition,
1897, Vol. XV.

Taruffi, Storia delli Teratologia, 8 volumes, Bologna, 1881-1895.

Hirst and Piersol, Human Monsters, Philadelphia.
Piersol, Teratology, Ref. Hndbk. Med. Sci., new edition, Vol. VII,
1904.

Ballantyne, Antenatal Pathology, 2 volumes, Edinburgh, 1904.

FE. Schwalbe, Die Morphologie d. Missbildungen des Menschen und
der Thiere, Jena, Pt. I, 1906, Pt. II, 1907.

PART <1:

HISTORICAL AND GENERAL.

HISTORICAL.*

The changes found in the pathological embryos to be
described in this memoir are so radical in nearly all specimens
that it is almost useless to speculate regarding the fate of the
embryos had they continued to grow to the end of a normal
pregnancy. Could the circulation be maintained these specimens

‘might have developed into amorphous monsters, a condition
which is probable only when there is a normal twin foetus to
supply the nutrition. In only one of my specimens (No. 87)
are the possibilities for such a termination present. Here on
one side of the chorion there is a normal embryo of the third
week and on the other side a highly developed umbilical
vesicle with but a rudimentary amnion, but no real body of
an embryo. In all of the other twin specimens the changes
in both embryos are radical and identical, so that we could not
hope to have had the one embryo dependent upon the other
for its circulation and nutrition.

In general then the changes in the embryo and its mem-
brane, due to the inflammatory action in the uterus, are so
great that if the ovum is not aborted at an early date (as it
usually is) it is converted into a solid mole which in the
course of time is likewise expelled. A few specimens, how-
ever, are but slightly changed, and these would probably have
grown into some sort of merosomatous monsters had they
been retained in the uterus. From my experience I am con-
vinced that in the study of specimens like these we have the
key by which we can unlock many of the mysteries of
teratology.

In my first two communications I carefully avoided
all speculations on this subject, for I was well aware of the
sad state this subject is in, and mere speculations would not

*The data here recorded are taken largely from Ballantyne’s Ante-
natal Pathology.
9

10 MALL. [VoL. XIX.

help teratology out of its difficult position. However, what
little progress has been made in the study of terata has been
made by the embryologist and we naturally still have conf-
dence in him. The course to be followed, therefore, is the
study of early abortions, and this I have done diligently.
I can, therefore, subscribe fully to what Ballantyne has
recently said in his able and scholarly treatise on antenatal
pathology. He says, page 77: “Now, in reference to the
inquiry into the problems of teratology or embryonic path-
ology, let me emphasize the importance of a thorough |
scrutiny of the foetal membranes and of the routine exami-
nation, microscopic as well as macroscopic, of all abortion
sacs and their contents thrown off in the early months of
pregnancy. What is most wanted at present are careful
descriptions of monstrous embryos from abortion sacs, obser-
vations upon teratological conditions while the organism is
still in the embryonic period of antenatal life. These are
essential for the further progress of a knowledge of human
teratogenesis, and they are at the present time the desiderata
of embryonic pathology. Microscopic human monstrosities
are, aS a matter of fact, almost unknown.”

The last sentence is hardly justifiable, for a pretty large
number of young pathological embryos have been described
by His, Giacomini and myself, but these do not resemble
monsters at full term any more than an embryo of the fourth
week resembles a new-born child. Whether the early path-
ological embryos are young monsters, or young monsters of
so extreme a degree that they will not continue to grow, is’
now the most important question of the capital problem in
teratology. I think that the specimens that are reported in
this publication contribute to the answer of this question, but
many more observations are required before the answer will
be accepted by all teratologists.

The history of teratology co-exists with that of medicine
and includes mythology, the vilest superstitions and scientific
embryology. The medical profession have abandoned the
idea of supernatural causes in the production of monsters

No. 1.] ORIGIN OF HUMAN MONSTERS. II

and have gladly exchanged the hybridity theory (cohabita-
tion with lower animals) for the more innocent one of
maternal impressions. The last notion is of great antiquity,
is of world-wide distribution and is intimately related to
witchcraft. It is gratifying to note that these superstitions,
based upon coincidences, have been raised from medicine by
the study of scientific anatomy, and the more recent work by
J. F. Meckel in this direction can be ranked with that of
Morgagni and Virchow. Morgagni gave the first blow to
humoral pathology by giving medicine an anatomical basis,
Meckel cast out devils, witches and mother’s marks by placing
teratology on an embryological basis, and Virchow won the
third great victory for anatomy, probably the greatest con-
tribution ever made to medicine, by giving it an histological
basis. It would be inappropriate to enter any further into a
discussion of teratogenesis in this publication, for in general
the superstitious notions are abandoned by scientific physi-
cians, although they may still be entertained by a few prac-
titioners of some eminence. It is humiliating to state that
these practitioners seem to reside exclusively in America,
but we have every reason to hope that when scientific medical
education becomes general with us they will also disappear.

Most of the great men who have contributed to the prog-
ress of medicine, from Hippocrates and Aristotle to the
modern scientists, tried to ascribe the production of mon-
sters to natural and not to supernatural processes. From the
first the explanations were as satisfactory as they are to-day,
for even now we barely do better than Aristotle did. How-
ever, the spread of the scientific spirit beginning with the
study and practice of anatomy by all medical students has
driven medical superstitions pretty well out of the medical
profession. In this respect we differ from the ancients. The
first scientific explanations were of a crude mechanical nature,
like those due to excessive lacing, malformations of the uterus
or a twin fcetus, which might injure the embryo. This notion:
was superseded in part by the theory of Morgagni, who
maintained that monsters were due to fcetal disease. This

12 MALL. [Vot. XIX.

again received its death-blow from J. F. Meckel, who pointed
out the well known fact that many structural anomalies are
hereditary. This observation naturally divided terata into
two groups: those which are hereditary and germinal, and
those which are not hereditary but due to mechanical injury
or disease. I think this line of division should be drawn
much sharper than it is, but until our data can be arranged
better than is now possible we are still quite uncertain re-
garding a large number of terata. It seems to me that many
merosomatous terata (all kinds of anatomical anomalies and
variations of the extremities, like polydactyly and possibly
some cases of arrested development like ectrodactyly and
hare-lip) are germinal and cannot be produced experi-
mentally. Other monsters in which more or less of the
foetus is destroyed, as in iniencephaly, spina bifida, anen-
cephaly, cyclopia, club-foot and many varieties of arrested de-
velopment, are not germinal but are produced in some me-
chanical way which usually interferes with the nutrition of
the embryo. In my notes I have been in the habit of calling
those belonging to the first group as being abnormal and
those to the second group as pathological. The one is
germinal with a hereditary tendency, and the other is acquired
and therefore not hereditary; polydactyly is inherited, cyclo-
pia is not, although there seems to be a tendency for it to
occur more than once in abortions from the same woman.
However, if this is true, it may be due to the same cause in the
uterus of the mother affecting the nutrition of successive ova,
thus producing similar deformities in the embryos. Usually
a woman who gives birth to several monsters has the varie-
ties mixed up pretty well, the first may have hydrocephalus,
the next hare-lip and the third cyclopia. Reducing it to a
matter of chance, a woman who has given birth to one
monster is more likely to give birth to a second one, which,
however, is rarely like the first. In experimental teratology
in birds and amphibia the result is the same. Here monsters
may be produced experimentally with a variety of agents,
even by treating the semen of toads with X-rays, but the

No. 1.] ORIGIN OF HUMAN MONSTERS. 13

variety of monster can never be predicted, and if there are
a number of them they are usually of mixed types.”

What I have to say in this publication of monsters applies
only merosomatous terata which are not of an hereditary
nature and are no doubt produced by agents which interfere
with the nutrition of the embryo. Having taken only those
monsters from which the germinal factor is excluded, it
makes it necessary once more to consider some minor me-
chanical agents as their cause, which may be termed a modified
mechanical theory.

The advocates of the mechanical theory gradually lost
ground, for they had to combat the germinal theory on the one
hand, and on the other they were compelled to state that me-
chanical influences, generally those due to lacing, caused the
foetus to become monstrous by the pressure that was exerted
upon it. The theory was then modified to include primarily
intra-abdominal influences like tumors, malformations of the
pelvis and uterus, as well as those within the ovum itself.
Gradually we see less and less weight placed upon any of these
specific causes, and finally the modern advocates of the theory
believe that amniotic bands and adhesions are the main influ-
ences in the production of monstrosities. It is needless to
state that each advocate had his own combination of circum-
stances, and when all of them are taken together, with modi-
fications and exceptions, it is practically impossible to make
general statements. Suffice to say that the objections to each
form of the theory appear to be sufficient to explode the
whole theory, and to the bulk of physicians maternal influ-
ences seem to be as rational a cause in the production of
monsters as mechanical influences, for the data of experience
are about as good in the former as in the latter.

There are some rare cases of spontaneous amputation of
the extremities which are said to be due to pressure of the
umbilical cord. However, these cases can be separated into
two marked groups, one in which there is an actual amputa-

*Bardeen, Jour. of Experimental Zool., 1907.

14 MALL. [Vor. XIX.

tion and the other in which there is an atrophic or rudi-
mentary hand or foot attached. In the latter instance it
seems to me that it is very irrational to hold the umbilical cord
responsible for the amputation. Furthermore, the cause is
possibly germinal, as may be the case in sympodia, syndactyly
and ectrodactyly. The rare cases in which there is actual
amputation of the extremity are more likely to have been
produced by mechanical injuries during labor than by having
the amputated limb caught in a loop of the umbilical cord.
In fact, we must admit that we are unable to explain by any
satisfactory hypothesis either congenital amputations or dis-
locations.

It has been noticed occasionally in merosomatous monsters
that the diseased or malformed part is tied by means of
bands of tissue either to the amnion or to adjacent parts of
the body of the fcetus. These observations, relatively few in
number, have led to the theory that the bands caused the
deformity. It seems to me that, in view of the idea that
many monsters are due simply to an arrest of development
of some part of the embryo, that hydramnios is usually pres-
ent, and that all kinds of monstrosities may be produced in
lower animals (including amphibia which have no amnion),
it is highly probable that amniotic bands and the like are
secondary in their formation and have nothing whatever to
do with the production of monsters. The more the embryo-
logical theory is tested by experimental methods the more
all simple mechanical explanations suffer, and it seems to me
that all of them will have to be abandoned.

It 1s not especially remarkable to find that when the head or
face is malformed the diseased part occasionally forms a sec-
ondary attachment with the amnion; or that, as in exomphalos,
where the umbilical cord is “dilated,” the extruded viscera
come in direct contact with the placenta, as they should, and
the blood-vessels are scattered and run along the amnion to the
placenta, as should also be the case when the subject is
viewed from the standpoint of embryology. Furthermore, de-
formities of the extremities are of frequent occurrence, but

No! Ee] s ORIGIN OF HUMAN MONSTERS. 15

amniotic bands are rarely found, and when they are present
they are often attached to the body of the embryo and not
to the deformed extremity. It seems to me, therefore, that as
facts accumulate it becomes clearer and clearer that the occa-
sional amniotic adhesions found are due to the presence of
the monster and are not causal in nature.®

Possibly I have devoted too much space to the discussion
of mechanical theories in teratogenesis. What has been said
is no doubt acceptable to all embryologists, and my apology
is due to the fact that the influence of maternal impressions
upon the offspring is still believed in by so large a number of
American medical writers of note and that mechanical notions
regarding embryology are entertained by physicians in general.

The great embryologists from Harvey onward explained
the conditions found in monsters as due to an arrest of
development, for they saw in these distorted individuals con-
ditions which are normally found in the embryo. The
embryological theory was first well formulated by J. F.
Meckel, who explained the beast-like appearance of some
monsters by the fact that in his development man passes suc-
cessively through stages found in lower animals. To those
who have accepted the doctrine of evolution this is all clear,
but it remains to be shown what are the factors in develop-
ment, and the effect of changes in the embryo upon the
growth of the foetus.

As has been pointed out above, we must divide monsters into
two groups, those in which the proper conditions to produce
them are already in the germ (are therefore inherited), and
those due to certain external influences which act upon
the egg after it is fertilized. It is obvious that only the
second group can be considered in any experiments made
upon the embryo. So, if the pathological ova I have studied

*Ballantyne says: “The reader may feel (and he is justified in so
feeling) that, after all, experimental teratogeny has not done much for
the understanding of the mode of origin of monstrosities, if it has
weakened a belief in the influence of the amnion.” I may add that this
argument can be applied to maternal impressions as a cause equally as well.

16 MALL. [Vou XIX.

are all due to a diseased chorion, which in turn is dependent
upon endometritis, then we should find embryos tending to-
wards club-foot, anencephaly, iniencephaly, spina bifida and
cyclopia, which in fact proves to be the case. However, a
large group of new monsters, known only to embryologists,
make their appearance and from the very nature of the abnor-
mality found but few of them could develop beyond the first
months of pregnancy. In their study comparisons have been
constantly made with normal embryos of the same size, and
in this way, to a certain degree, it is possible to picture the
order of events. It is found that in these specimens some
tissues are more susceptible than others, and when the nutri-
tion of the ovum is impaired it is these that are affected first.
In very early stages the amnion and embryo are equally
susceptible and the umbilical vesicle and chorion are the
most resistant. Later it is the embryo alone, and still later
the head, central nervous system and extremities. It fol-
lows then that the parts most susceptible are those most
frequently found changed, or wanting, in merosomatous non-
germinal monsters. In general the varieties found in my col-
lection of young embryos correspond with those obtained
experimentally by others in birds and appear much like the
most common human monsters.

The Saint-Hilaires, who contributed so very much to our
knowledge of teratology, were the first to study the subject
experimentally. By a variety of experiments made upon the
shell of the egg (e. g., pricking and varnishing) the older
Saint-Hilaire produced a large number of anomalies in which
there were defective heads and spina bifida. Huis experiments
were made upon eggs after development was well under way,
and his results were pronounced enough to allow of com-
parison with human monsters. The younger Saint-Hilaire
extended the experiments to include the earliest days of
incubation, and found that the embryos which developed were
dwarfed or were wanting altogether. In no instance were
polysomatous monsters produced. At any rate, the experi-
ments of the Saint-Hilaires show that a change in the external

No. 1.] ORIGIN OF HUMAN MONSTERS. 17

physical conditions may influence and modify normal develop-
ment and thereby produce a variety of merosomatous terata.

During the following seventy-five years a great amount of
experimental work was done upon chicks by numerous inves-
tigators, which showed that the varieties of monsters pro-
duced were quite constant, no matter what agent is used, but
no single variety could be produced with certainty. It was
found impossible to experiment with precision, for a certain
per cent of eggs would produce one or more varieties of
deformed embryos.

EXPERIMENTAL.

RECENT WorK UPON THE PRODUCTION OF POLYSOMATOUS
MONSTERS.

The various theories regarding teratogenesis which had
troubled mankind for so many centuries were finally exploded
by naturalists, whose speculations gradually led them to ex-
periment upon this subject. Anatomists and zoologists had
deduced that the primary change lay in the egg about the
time of fertilization, and we read in J. Miller,t Valentin? and
Leuckart® that a double monster is due to division of the
embryo-forming substance in the earliest stage of develop-
ment. The experiments subsequently made by Gerlach,*
Panum® and Dareste® upon chicks were negative in this
respect, but the tradition has come down to us that polyso-
matous monsters are produced by a process of splitting of the
primitive streak. The more recent anatomists—Fol, Rauber,

*Miiller, Meckel’s Archiv, 1828.

*Valentin, Handworterbuch d. Physiologie, I, 1842.

*Leuckart, De Monstris, Gottingen, 1845.

“Gerlach, Doppelmissbildungen, 1882.

*Panum, Entstehung der Missbildungen, 1860.

°Dareste, Recherches sur la production de monstrosités, Paris, 1891.

18 MALL. [VoL. XIX.

Born and O. Hertwig—who observed the developing egg and
experimented upon it, were at first inclined to the theory that
the first cause in the production of monsters is due to poly-
spermy, but this has not been substantiated.

The first reliable and valuable observations upon the pro-
duction of double monsters were made by Vejdovsky,’ who
noticed that the eggs of Lumbricus produce more monsters in
warm than in cool weather, and he expressed the suspicion
that they were produced by the change in temperature.
Driesch® seized upon this idea, experimented upon sea-urchins’
eggs, and found by subjecting them to high temperatures that
the cells, in the two-cell stage, separated, each growing into
an individual, but, however, remaining connected with each
other. Driesch had already shown that when the blastomeres
of these eggs are fully separated by shaking, each grows into
a whole embryo, and it was now clear to him that double
monsters are produced by separating the blastomeres slightly,
but still keeping them close enough together so that the inde-
pendent embryos grow into each other’s bodies to form a
double individual.

By a very different method double monsters were also pro-
duced by Loeb.® He subjected sea-urchin eggs to an equal
mixture of sea-water and distilled water shortly after they
had been fertilized. The rapid absorption of water caused
many of the cell membranes to burst, and part of their proto-
plasm escaped, which, however, remained connected with that
inside of the membrane. All this took place before the nucleus
had divided. Upon returning the eggs to normal sea-water
cleavage began, and one of the first two nuclei wandered into
the extruded protoplasm. Each nucleus with its protoplasm
then became an embryo, and in case the embryo within the egg
was not separated from the extra-ovate embryo by its active
movements in the blastula and gastrula stage a double monster

*Vejdovsky, Entwicklsg. Untersuchungen, Prag, 1890.

*Driesch, Zeit. f. wiss Zool., LV, 1892.

"Loeb, Biological Lectures at Woods Holl, 1893; Pfliiger’s Archiv,
LV, 1894; Roux’s Archiv, I, 1895; and Studies in General Physiology,
Chapter X, Chicago, 1905.

No. 1.] ORIGIN OF HUMAN MONSTERS. 19

or “Siamese” twins were formed. Frequently they became
separated and independent animals developed. It often hap-
pened that the outflow of protoplasm was multiple, and then
the three, or even more, protoplasmic drops which were
formed developed respectively into triple or quadruple
monsters.

These important discoveries were soon extended to the
vertebrates by E. B. Wilson,’® who experimented upon the
eggs of Amphioxus, and by O. Schultze,*? who experimented
upon those of the frog. Wilson partly separated the blasto-
meres of Amphionus in the two-celled stage and produced a
variety of double monsters which developed until the first
gill-slits were formed. In the gastrula stage almost every
possible transition occurred between forms slightly expanded
laterally to those in which the two bodies were joined only by
a slender bridge of tissue. Incomplete separation of the blas-
tomeres in the four-celled stage gave rise sometimes to double
embryos of equal size, triple embryos, one being as large as
the other two, or rarely to quadruple monsters. Wilson’s
studies prove, he believes, “that the unity of the normal
embryo is not caused by a mere juxtaposition of the cells, but
they indicate that this unity is not mechanical but physiolog-
ical, and point toward the conclusion that there must be a
structural continuity from cell to cell that is a medium of co-
ordination, and that is broken by the mechanical displacement
of the blastomeres.”

Oskar Schultze produced monsters in frogs by fixing the
eggs between two glass plates, and after they had developed
to the morula stage the plates were inverted. A number of
the eggs righted themselves, but others grew into double
embryos. Wetzel'* extended the observations of Schultze
and showed that there was a flow of protoplasm in each of
the blastomeres into their upper hemispheres, which may

*Wilson, Jour. of Morph., 1893.

%O. Schultze, Verhandl. d. anat. Gesellsch., 1894, and Roux’s Archiv,
I, 1895.

*Wetzel, Arch. f. mik. Anat., XLVI, 1895.

2

20 MALL. [VoL. XIX.

account for the separation of the primary cells, thus laying
the foundation for two embryos instead of one.

Spemann'® has also produced polysomatous monsters from
the frog’s egg by tying a ligature loosely around it in the two-
cell stage between the two blastomeres. Specimens in which
the ligature struck the median plane of the embryo produced
two-headed monsters of all grades, their development de-
pending somewhat upon the degree of the mechanical con-
striction. He performed similar experiments upon Triton
eggs, and in some instances found cyclopia in one or both of
the heads. By broadening the anlage of the tail through
splitting, a double tail may be formed, or in case limb-buds
are divided one or more times two or even a cluster of limbs
may be produced where but one develops normally.“

The experiments enumerated above, although not quite to
the point in the present study, are reviewed because they show
that teratogenetic problems are solved by experimental em-
bryology and because they are very striking. If it is clear
that polysomatous monsters are produced experimentally
with such precision, the great variety of merosomatous terata
of the experimenter must be admitted worthy of careful study.
It is necessary to state this because only a small per cent of
them live for some length of time, but they show a great sim-
ilarity with early stages of human terata with which we are
familiar. A glance at the great works of Dareste and Panum
makes it clear that the deformed embryos they obtained are not
easily interpreted and they could easily be pushed aside as not
bearing upon the subject in question. The same criticism may
be made against early pathological human embryos. That it is
difficult to see any marked relation between them and monsters
at the end of pregnancy caused me much confusion for a
long time, but after studying a large number of deformed
embryos I am finally convinced that the pathological embryos
are nothing but young monsters. This conclusion is sup-

*Spemann, Stizungsber. d. phys.-med. Gesellsch., Wurzburg, 1900;
Zool. Jahrbuch, VII Supplementband, 1904.
“Tornier, Roux’s Archiv, XX, 1905.

No. 1.] ORIGIN OF HUMAN MONSTERS. 21

ported especially by the numerous investigations in experi-
mental embryology, many of which are also at the same time
investigations in experimental teratology. For this reason I
shall consider briefly the recent work upon the production of
merosomatous monsters.

Liruium Emsryos anp NopuLar Forms
IN CHICKS AND IN MAN.

Comparative teratology gives ample testimony to explain
the production of double monsters, and it is now clear how
they may be produced in man. But when the study is ex-
tended to merosomatous terata great difficulties arise in making
comparisons between the large number of experimental mon-
sters in lower animals, the pathological embryos which I have
studied, and finished monsters at the end of pregnancy. The
endless literature upon these subjects is very difficult to blend
into a continuous story on account of the various terminol-
ogies used by the different writers. However, I hope to draw
some satisfactory lines through it, being guided by compara-
tive anatomy and embryology. ©

The immense number of experiments performed upon the
eggs of different species of animals has given the greatest
variety of monsters of very irregular form, and extremely
difficult to interpret properly in the light of our present knowl-
edge of embryology. Quite recently our distinguished tera-
tologist, Morgan, has presented this problem in a new light
in his series of studies on the relation between normal and
abnormal development of the embryo of the frog. No doubt
scientific investigations like these of Morgan will soon clear
up many of the questions in teratology which have perplexed
us so long. It may be noted that new kinds of monsters are
constantly being produced by the experimental teratologist,
one of the most interesting being that known as the lithium
larva.

*Morgan, Ten Studies in Roux’s Archiv, Vols. XV-XIX, 1902-1905.

to
to

MALL. [Vot. XIX.

In 1893, Herbst,” while studying sea-urchins’ eggs, observed
that the action of lithium salts upon them caused the layers
of the blastoderm to invert in development. The lithium ex-
periments were repeated by others, including Morgan, upon
frogs’ eggs, who found that the upper protoplasmic contents
of the egg fails to move downward, which is followed by a
complete inversion of the germ layers. The entire upper part
of the egg sinks into its interior and forms a medullary plate
which is bent back upon itself. This change in development
is due to the physical and chemical action of lithium salts, for
it cannot be brought about by any other means.

Very recently Stockard* experimented upon Fundulus with
solutions of lithium chloride and produced monsters which
developed into quite decent fishes, but at present it is impos-
sible to compare them with lithium larve of sea-urchins and
frogs. In these embryos the blastoderm is usually prevented
from growing downward over the yolk, as is also the case in
the frog, and therefore bulges as a cap upon the upper part
of the egg. In stronger solutions of lithium this cap often
constricts at its borders and finally pinches itself off from the
yolk and dies. In embryos which survive, the heart beats
slowly, the eyes often fail to develop, the blood is colorless and
therefore appears to lack hemoglobin. These characteristics,
taken with the inability to recover from the lithium effect,
seem to prove that they are due to chemical causes.

At present it is difficult to compare the great variety of
monsters produced in anamniotic with those obtained in
amniotic animals, for the number of the latter is relatively
‘small and their description meager. We have a series of
excellent papers on the production of monsters in the hen’s

‘egg by Panum,* Dareste> and Féré.6 These authors, how-
ever, devoted their main discussion to the teratogenic agents,

*Herbst, Mitth. Zool. Sta., Neapel, 1893, and Roux’s Archiv, 1806.
» Jour. Ex. Zool., Baltimore, 1906.

‘Panum, Entstehung d. Missbildungen, Berlin, 1880.

*Dareste, Recherches sur la production de monstrosités, Paris, 1891.
*Féré, Cinquantenaire de la Société de Biologie, Paris, 1899.

No. 1.] ORIGIN OF HUMAN MONSTERS. 23

of which they used a great variety. In general, they employed
variations in temperature during incubation and, although
they produced many kinds of monsters, they never could
predict which kind they were to obtain from a given batch of
eggs. It is, therefore, very apparent why experimental tera-
tologists did not make much headway as long as they experi-
mented upon the chick. However, they did establish two facts:
first, that monsters are produced from the hen’s egg by all
kinds of external influences, as varnishing the shell, placing
the egg in the vertical position, change of temperature, trau-
matic means, shaking, magnetic and electrical influences, by
gases which penetrate the shell and by a great variety of
chemical poisons and toxines injected into the white of the
egg. In general, any substance which either interferes with
the nutrition of the egg or poisons it, causes the embryo to
become abnormal, but a special kind of monster is never
produced by a given teratogenic agent. In this respect the
experiments upon anamniotic eggs are far more satisfactory.
Panum classified the monsters he produced into two great
groups: (1) Those in which the whole embryo is involved,
(2) those in which but part of it is abnormal. Under the
first group there are (a) flattened forms, that is, the germinal
area is not much changed in shape; (0) flattened forms with
the production of red blood, i. ¢., only the embryo is affected ;
(c) cylindrical forms, the embryo becomes abnormal in a more
advanced stage; and (d) amorphous forms. This first group,
with its four subdivisions, may possibly be compared with the
great variety of irregular monsters of which the lithium larva
may be considered the type. At any rate, we may say that
there is an analogy. Certainly there is a similarity between
the cylindrical forms, which do not live long, and the de-
formed fishes obtained from Fundulus by means of lithium -
chloride solutions. The great change which has taken place
in both varieties makes it impossible for either of them to
exist for a longer time. A similar form of monster is also
often found in mammals, and His, in adopting Panum’s ter-
minology, has classed it with cylindrical monsters. The

24 MALL. [VoL. XIX.

pathological changes ii them are so radical that their lives
are also short. Amorphous forms are analogous with lithium
larve and identical with the nodular form in man. In gen-
eral, only part of the embryo continues to develop in an
irregular fashion and finally the whole embryo dies. The
flattened forms, with and without blood-vessels, are identical
in man with the vesicular forms, that is, ova containing
umbilical vesicles only, and to ova without embryos, respec-
tively.

The merosomatous monsters in which the whole embryo
is affected, total monsters as they are also called, are not
likely to live long, but they are of great interest to those
studying teratological problems. While they are being formed
a certain number of eggs develop into partial monsters, and
in man some of them grow into foetuses which may go on to
full term, and a very small number of them live on to maturity
after birth.

The recent total monsters produced by Bardeen’ in sub-
jecting the sperm of toads to X-rays before fertilization can
be explained on the same ground as are lithium embryos. The
tadpoles which develop from such eggs are entirely diseased,
continue to grow in an irregular manner and appear much like
lithium larve in Fundulus or as ordinary pathological embryos
in man. In all three cases the primary radical change involves
the whole embryo; in Bardeen’s experiment the cause af-
fected the sperm before fertilization, in Fundulus shortly
after fertilization, and in human pathological embryos some-
what later. Although the methods employed are very differ-
ent, the principle involved and the results obtained are much
the same.

A very large number of monsters are to be classed as total
monsters. They are probably brought into existence by a
variety of circumstances, all of which interfere with the
nutrition and growth of the whole embryo and the changes
in them are so radical that their lives are very short. In man

"Bardeen, Jour. Ex. Zool., IV, 1907.

No. 1.] ORIGIN OF HUMAN MONSTERS. 25

the primary trouble cannot be due to the presence of poisons
in the blood of the mother, to correspond with chemicals used
by teratologists in producing lithium larvz, for instance, nor
to a fever, to correspond with the changes in temperature
used to produce chick monsters. The process in man is quite
different, being due probably to faulty implantation of the
ovum, which naturally affects the growth of the embryo.
This will be discussed under a subsequent heading.

EXPERIMENTS WITH SALTS OF POTASSIUM AND CHANGES OF
THE EMBRYO ESPECIALLY MARKED IN THE HEART.

In case interference in the nutrition of the embryo is not too
great the growth of part of the embryo, instead of all of it, may
be retarded, with an additional destruction of tissue, thus pro-
ducing the partial monsters in man, which frequently develop to
full term. However, there is every kind of gradation between
total and partial monsters, the former often showing many
indications of the latter and the latter are frequently multiple.
A total monster may have spina bifida, hare-lip, anencephaly,
club-foot, cyclopia, etc., and a partial monster may include
several of these types.. The primary affection which is to
produce a pure spina bifida in man must be slight, must come
at the right time, and subsequently the faulty implantation
must be remedied so that the embryo may continue to ‘grow.
In order to make my standpoint clear I shall first give
some data regarding the frequency of some types of monsters
as well as some experiments which show that the heart is
extremely susceptible, its growth being easily retarded and
often arrested after the embryo is well formed.

Von Winckel has given us some data regarding 87 mon-
sters obtained from 12,378 births in Dresden, that is, there

*Von Winckel, Ueber die mensch]. Missbildungen, Samml. klin.
Vortrage, Leipzig, 1904.

26 MALL. [Vou. XIX.

was one monster in every 142 children born. He also states
that there were 105 monsters in 20,000 births in Munich, or
I to 190. The most marked deformity in each of the 87
Dresden cases number as follows:

Deformities of the head ee ieee. cee eee 23
Deformities: of ‘the: face. ee 6 ee ee 12
Detormities Of the necks eee ee eee 4
Deformities: of the abdomens ect eee 7
Deformities ofthe Dacken a= eee eee a
Deformities ‘or te upper extremity seen 9
Deforimities:of the Wower extremity o- eer. e- 17
Deformitiesxerthesskiner sores cit. ae ees iti
Deformittessor orueimoncansher, tae ee ee I

I have compiled a similar table from Panum,? who gives
data obtained from Otto and from Meckel. It is as follows:

Total number Number of

of monsters. cases.
AMmencephalis ce stakes ene 618 119
Anencephalus (according to Bal-
lantyne 2h oe alee Sats 325 46
Py drocepialis.s heen te on; cemstes uses 618 26
EHydrocephaloedle: vs nie 2 tee 618 93
THarelip, ave eat aaa 618 7G.
Cyclopia 2h.c vont he et eae eee 618 16
Eyes siissitieng.. hein aren eek eee an 618 9
Deformed aipper jaw eai-ne seis 618 3
Deformedtextrenities sie antennae 618 II5
Spinanbihida dicate sated ean ewre 404 38

In my collections of 163 pathological embryos there are 48
which show deformities which can easily be recognized as
similar or as being forerunners to foetal monsters. In 27 of
the embryos this deformity is limited to a single part of the
embryo, as indicated in the table, but in 21 of them two or

*Panum, J. c.

No. 1.] ORIGIN OF HUMAN MONSTERS. 27

more malformations are present. They are as follows. Total
number of cases, 48.°

Atrophic: Head vacate a ee eye Att ok ee het 24

Malktorntied: facesandcmecks eye, wet si ta aes 17
Bisplaced* eyes st. oes emer bye ace a otto 3
Detormed extremities: \ nia ta eae 18
AS [DOA CT (G Dar Aa Oe PPE ER piper oR 12
EPROP all yore og 6 Bla sea ay, eran ete pate 5

In a general way the deformities in these 48 malformed
embryos correspond pretty well in per cent with the type
of monsters as recorded by Von Winckel and Panum. As
shown in the table on page 43, seven pregnancies out of every

“In order to make it possible to look up the histories of the embryos
given in this table I add the numbers of the specimens which are included
under each heading:

Atrophic Face and Eye. Extremities. Spina bifida. Exomphaly.

Head. Neck.
12 110 135 81 6 II5
60 122 201 04 12 162
69 124 285 122 54 166
81 132 124 94 244

104 201 132 135 364

132 212 135 182

135 226 142 189

137 232 177 226

177 246 200 251

182 251 230 203

189 276 232 364

200 207 251 365

201 330 316

207 343 325

212 357 343

226 364. 344

276 365 357

295 366

309

335

341

343

364

365

28 MALL. [VoL. XIX.

100 give pathological ova of which but one-third give well
formed embryo monsters, or two per cent of all pregnancies.
The number of monsters which go on to full term is about .6
per cent, and it is just this group which has escaped me. The
embryo and foetal monsters form, therefore, 2.6 per cent of all
pregnancies, or, in other words, three well-formed monsters
are aborted in the early months of pregnancy for every one
which goes on to the end of pregnancy.

It is clear that those cases in which the embryo is markedly
deformed or is absent altogether, as is the case in about 100 of
my specimens, cannot possibly develop for any great length
of time, for without either heart or form they cannot exist.
However, the second group of forty-eight embryo monsters
show within themselves such radical changes that they also
could not have existed much longer. In nearly all of them the
heart is markedly changed, is atrophic or is wanting altogether.
There are also many other changes, especially in the central
nervous system, which makes it probable that they have lived
as long as they could and were then finally aborted. In
general, I think that the form of the monsters and their clas-
sification show clearly that they are practically identical
with those that grow into foetuses and then to full term, differ-
ing only in the degree of their changes. These are so radical
in the embryo monsters that their lives are destroyed.

Teratologists have long ago observed that the heart must
be affected more or less in monsters on account of the fre-
quent oedematous condition of the tissues and of the excessive
accumulation of fluids in the serous cavities and in the
amnion. In fact, a large per cent of monsters have hydro-
cephalus and hydramnios. These conditions are seen in
many of my specimens and have been observed by experi-
mental teratologists like Panum and Dareste. However,
we now have some good experiments which throw some light
upon this subject.

In 1893 Loeb* made the brilliant discovery that the heart
beat could be arrested in Fundulus by placing the eggs in a

“Loeb, Pfliiger’s Archiv, LIV, 1893.

’

No. 1.] ORIGIN OF HUMAN MONSTERS. 29

I.5 per cent aqueous solution of potassium chloride shortly
after fertilization. He found that the eggs develop in a pretty
normal fashion with the exception that though the heart de-
velops it does not beat at all. The blood-vessels develop prop-
erly as regards their course and division, but their lumina are
irregular, like a chain of beads, which Loeb believes to be
due to a lack of normal blood-pressure. Similar pictures
may be seen in pathological human embryos, that is, only part
of the vascular system is present, or the heart is atrophic but
some of the blood-vessels are present, or the whole vascular
system of the body is absent, with remnants of vessels in
the yolk sac and in the chorion. In the last instance the
vessels of the body may have been present at one time, for
they should not have reached the chorion without passing
first through the body. The embryos in Loeb’s experiments
rarely hatched, and all of them died before the sixteenth day,
due to heart poisoning. Loeb thought that all of the organs—
brain, eye, ear and myotomes—developed without any marked
anomalies, but I do not think that his experiments were ex-
tensive enough to test this point thoroughly. However, he
states that the pigmentation of the yolk sac was affected
decidedly by the absence of the circulation. Under normal
conditions the pigment, which is at first evenly scattered over
the yolk, wanders to the blood-vessels as soon as the circu-
lation begins and stays there, forming pictures which corre-
spond with the branching vessels. In potassium embryos where
the blood does not circulate the pigment cells are not attracted
to the blood-vessels, but remain scattered evenly over the
yolk.

By extirpating the heart anlage from very young frog em-
bryos Knower® obtained a similar arrest in the development,
but his experiments show that absence of the heart or early
defects in its action produces marked abnormalities in the de-
velopment of the embryos. While the earlier stages of the
development of these frog embryos is normal, the later changes

®Knower, Anatomical Record, Amer. Jour. Anat., VII, 1907.

30 MALL. [Vor. XIX.

are arrested and strikingly abnormal. These embryos grow in
an irregular fashion, become cedematous and the lymph vessels,
blood-vessels and serous cavities are distended. Especially is
the pronephros thus affected and the glomerulus distorted.
The vascular system is much distended and very irregular, the
chief vessels being laid down, though incomplete. The aorta
and pronephric sinuses open into a mesenteric sac. The capil-
lary system is imperfect or absent, blood corpuscles are rela-
tively few and apt to be collected in the enlarged sinuses. Re-
markable also is the role the lymph hearts play in such speci-
mens. They continue to beat and pump the lymph containing
some blood into the veins, and from their periphery it must
pass again into the tissues. In connection with arrest in the de-
velopment of organs the coiling of the intestines is limited to a
single loop, the pancreas and liver are not normal, the sub-
divisions of the brain do not acquire their specific size and
shape, the eyes are much aborted and the musculature is vacu-
olated. Knower obtained similar results from frog embryos
developed in acetone chloroform, which inhibits the heart
action from its earliest stages.

The recent experiment of Bardeen, in which he produced
toad monsters by subjecting the sperm to the influence cf
X-rays before fertilization, may also bear upon the question
of the importance of the heart in early development. “The
eggs develop at first apparently normally or even better than
the control, but beyond the gastrula stage the development
begins to become retarded, and at the time of hatching, as
the tail begins to grow out, marked deformities begin to
appear in the larve.” The change takes place at the time
the heart begins to function, for the vascular system was
barely developed in any of the embryos experimented upon.
The heart is rudimentary and may have no continuous lumen.
The chief arteries and veins are incompletely developed.
There are but few blood corpuscles in any of the embryos,
and Bardeen® states that it is uncertain whether the blood had

“Bardeen, Jour. Ex, Zool., Baltimore, 1907.

No. 1.] ORIGIN OF HUMAN MONSTERS. 31

circulated at all in any of the embryos. In all of them the
spaces in the tissues indicate that there is a marked oedema.
The mesenchyme is increased in amount, the cells being spread
apart by the fluids between them. Unfortunately for my
purpose, Bardeen has not examined early stages of his mon-
sters, nor has Loeb examined with sufficient care the later
stages. If we keep Knower’s experiments in mind, we may
think for the present that the changes in circulation in Bar-
deen’s experiments are primary, and the other changes, like
irregular development of the nervous system, dropsy and
hydrocephalus, are secondary, that is, due to the absence of
the circulation. At any rate, Bardeen’s description of his
“X-ray toads” corresponds in many respects with those I
have given of pathological human embryos in earlier publica-
tions and in Part III of this publication.

It is also clear that the necrotic changes in the central
nervous system of these larvz, as well as those in pathological
human embryos, can be due to deficient nutrition, but in order
to produce a finished monster the nutrition must not be im-
paired too much. The heart may be poisoned sotnewhat,
which in turn may affect the central nervous system, causing |
histolysis and dissociation there, and the general development
may be retarded and the embryo deformed, but as soon as the
heart ceases to function all growth ceases and the embryos
gradually disintegrate, as has been the case in about 100 speci-
mens out of my 169.

In very rare instances human embryos continue to develop
to the end of pregnancy without a heart. Such a specimen
must be one embryo of duplicate twins, with a common
umbilical cord through which it may receive nourishment
from its healthy brother. Quite early in development its
circulation must be reversed in the descending aorta, for as
soon as its heart stops blood enters the body through the
umbilical arteries, which passes in a reversed direction up
the descending aorta. Under these conditions all kinds of
curious monsters develop, ranging from a single head with-
out a body to a kind of teratoma known sometimes as a

32 MALL. [Vor. XIX.

placental parasite. Of course, a “rescue” like this is out of
the question in nearly all cases, and the life of the embryo is
of short duration after its heart has ceased to beat.

Specimens similar to Bardeen’s and mine have often been
found in chicks by Dareste and by Panum. Panum describes
quite extensively the changes which take place in chick mon-
sters. He recognizes in his classification that flattened mon-
sters are of two kinds: (1) Anzmic ones, in which no blood
is found, and (2) those in which red blood had been found
but most of the vessels are retained in the area vasculosa. In
these probably the vascular anlage was destroyed very early
or it began in the area vasculosa and did not develop into
the embryo. The result is similar to that obtained by Bar-
deen, Knower and myself.

It is clear, I hope, that certain parts of the embryo are more
susceptible to insults than others, and this must be admitted in
order to explain why potassium stops the heart, lithium affects
in a peculiar way the movement of the protoplasm in the
blastomeres, and sodium produces spina bifida by arresting
the movements which close the spinal canal. In order to
analyze the situation we must concern ourselves mostly with
simple reactions in their early stages, for they are not under
way long before they become very complex and beyond
our reach. Mesenchyme is less susceptible than nerve tissue,
and the brain is more susceptible than the spinal cord; and
so on. A susceptible tissue when affected undergoes certain
morphological changes well recognized by Panum. Panum
pictured to himself a kind of inflammation of the tissues,
parenchymatous, due to disturbances in the nutrition of the
part, but it is by no means clear that anything like inflamma-
tion in the healing of wounds takes place in embryos or in
the various tissues after they have become partly necrotic.
Often it is noticed that cells accumulate in portions of the
embryo, and His thought that they wandered out from the
blood-vessels. In my former publications I spoke of these
cells as the wandering cells of His. Hertwig and Bardeen
speak of necrosis, and there is every evidence that destructive

No. 1.] ORIGIN OF HUMAN MONSTERS. 33

and not constructive processes are present in parts of the
embryo which are becoming deformed. As this question is
being investigated more and more it is clear that we must
build up a pathology of our own based upon observations
upon normal healing of wounds,’ etc., in embryos, just as
Morgan was compelled to study anew the development of the
frog in order to interpret properly the various malformed
eges he had under consideration.

I am quite certain that in the human embryo the cells may
spread from the blood-vessels into the surrounding tissues
after the heart has stopped, and I am also certain that mesen-
chyme cells may separate and segregate, and that the cells of
the central nervous system may become necrotic in part, dis-
solve their connections and gradually fill the central canal.
It matters little what we call this process, it probably includes
a series of processes, but for the present I shall apply to it
the term dissociation. In doing this I do not commit myself
as to the origin of a group of cells. In order to describe my
human embryos properly I must also use the term macera-
tion, and by it I mean that the process has taken place after
the death of the part. When cells dissociate they are still
alive, but they are on the way to meet their fate. As the
tissues continue to grow their sharp, borders are broken and
they gradually become hopelessly confused. For the present
the terms dissociation and maceration will do; in a short
time it will be necessary to displace them, for experimental
teratology will continue to be a fruitful field of research.

Sopium Monsters—SPpiInA BIFIDA AND ANENCEPHALY.

Probably the most satisfactory chapter at present in experi-
mental teratology is the subject of spina bifida. Under this
heading, of course, is meant that kind of spina bifida which
is due to a lack of closure of the neural canal and not the
kind that may be produced in older embryos after the cord is

"See, for instance, Eycleshymer, Amer. Jour. Anat., VII, 1907.

34 MALL. [Vor. XIX.

formed perfectly and the vertebral canal remains open. How-
ever, it is easy to conceive of the second kind as a variety of
the first, for in it the development went on normally, but the
vertebral arches did not meet in the dorsal mid-line to pro-
duce the vertebral canal.

In 1892 O. Hertwig! published his remarkable article on
open blastopore in frogs’ eggs and its relation to spina bifida.
Hertwig was experimenting upon eggs to produce poly-
spermy, after they had been kept for some time after matura-
tion and found that many of these eggs developed abnormally,
due to polyspermy, he believed. A part of the eggs segmented
irregularly and developed in a peculiarly pathological fashion,
that is the blastopore remained open much longer than it
should. The further study of these specimens showed that
they grew into embryo monsters with all kinds of deformity
of the spinal canal, often producing quite typical specimens
of spina bifida. Hertwig saw clearly the bearing of these
experiments upon the general explanation of spina bifida and
its relation to the blastopore. This he discusses at great
length and with much ability. He was able to show the rela-
tion of his work with that obtained by Lereboullet on the
pike, by Oellacher on the salmon, and by Rauber on the
trout. These investigations had shown that an open spinal
canal or even a total fissure of the body may result when the
germ ring does not unite properly to form the body of the
embryo.

It now became possible for the first time to follow spina
bifida from its very earliest stages in amphibian and fish
embryos up to a time when it is clear that the process is
identical with that found in birds and mammals. ‘To be sure,
in the latter cases we must take the specimens as they occa-
sionally come to us, for it is impossible at present to experi-
ment upon mammals successfully, and in chicks the ex-
periments are not very satisfactory. This comparison was
made by Hertwig with great acumen, using the excellent

*Hertwig, Arch. f. mik. Anat., XX XIX, 1892.

No. 1.] ORIGIN OF HUMAN MONSTERS. 35

article of Von Recklinghausen” upon spina bifida as a repre-
sentative one for man.

About the same time Morgan and Tsuda,* in working upon
the orientation of the frogs’ eggs, subjected them to a great
variety of solutions, and found that a .6 per cent solution of
sodium chloride prevented closure of the blastopore. By them
the nail was hit upon the head; the other investigators only
obtained monsters occasionally (Hertwig incorrectly believed
them to be due to polyspermy), but Morgan and Tsuda ob-
tained them in great number. It was found that less than .6
per cent of salt did not affect the embryo and a stronger
solution killed it. Successful specimens, and there were many
of them, were examined from stage to stage in their develop-
ment and the exact steps by which the blastopore is closed
was followed. This gave them a decided advantage in study
over the hap-hazard one in finding embryos already formed.
The experiments were used mainly to study the orientation
of the embryo in its relation to the lips of the blastopore.

The crucial experiment of Morgan and Tsuda was imme-
diately seized upon by Hertwig* and employed in his experi-
ments on spina bifida. Spina bifida could now be studied
experimentally. Hertwig also found that a .6 per cent solu-
tion of common salt delayed the development of frogs’ eggs,
the intestines, chorda, myotomes and nervous system develop-
ing normally, but gastrulation was postponed for from twelve
to twenty-four hours. As a result of this the spinal cord
does not close posteriorly as rapidly as it should and perma-
nent spina bifida follows. Often the walls of the spinal tube
are thin and its lumen is small, showing that there is a
general arrest of its development.

In general, Hertwig did not continue the experiments
beyond the sixth day, for the salt caused marked changes in
the exposed spinal cord. It seemed to be less resistant, inas-

*Von Recklinghausen, Virch, Arch., 105, 1886.

®Morgan and Tsuda, Quart. Jour. Micr. Sci., N. S. 35, 1894. Also,
Morgan, Roux’s Archiv, pp. 266, 269 and 293, 1902,

*Hertwig, Arch. f. mik. Anat., XLIV, 1905.

3

36 MALL. [Vov. XIX.

much as it underwent histolysis and cytolysis. The epider-
mis also showed changes; instead of being smooth on the
outside it became rough, grew up into numerous papillomata,
as Bardeen found in his X-ray larve, and as I have often
found in pathological human embryos.

Hertwig explained Morgan’s remarkable experimental
production of spina bifida by assuming that the concentration
of the salt retarded the growth of the cells of the egg and
that the reduction of energy is unequal in different portions
of the egg. Through this change differences in the rate of
growth are established unlike those in the normal embryo,
which naturally ended in the production of an abnormal
embryo, that is, a monster. In this instance Morgan’s sodium
larva is the typical embryonic stage of spina bifida.

The spina bifida, although complete at first, rarely remains
so, for the neural tube closes more or less, remaining open
usually behind and often in front, giving quite typical speci-
mens of anencephaly. It is clear, therefore, that this variety
of spina bifida is also due to an arrest of development
which could easily undergo secondary changes and produce
a condition which is often found in foetuses at full term.
Hertwig concludes, properly so, I think, that every human
ovum has within it the power to develop into a monster,
either anencephalic or otherwise, and that it is not due to any
abnormal condition of the germ, but to external influences
which affect the growth of the egg. A monster is due to the
influence of external substances which retard the growth of
the embryo, usually one portion more than the other. For a
long time teratologists have practically stated the same in
recognizing that monsters usually represent arrestments of
normal development. Not only is this true regarding mero-
somatous monsters, but every egg has within it the power
to develop into a polysomatous monster, or into duplicate
twins.

Later Hertwig® extended Morgan’s experiments to Axolotl,
thus making it applicable to at least six species of animals.

"Hertwig, Gegenbaur’s Festschrift, II, 1896.

No. 1.] ORIGIN OF HUMAN MONSTERS. 37

In this animal the monster lives much longer than the larve
of frogs and toads do, and for this reason terata with spina
bifida or anencephaly are obtained that resemble very much
those found in man. It was found that a .5 per cent solution
of NaCl produced no perceptible effect on Axolotl, that a
.6 per cent solution made half of them grow into monsters,
and in a .7 per cent solution all of them had spina bifida. In
them it was found that the neural tube did not close regu-
larly, and often several dorsal openings remained, some until
the embryos were quite large. In frogs gastrulation was
affected decidedly by the .6 per cent solution of salt; in
Axolotl gastrulation remained normal in the .7 per cent solu-
tion, the change being confined to the brain and cord, but did
not extend to its caudal end. The exposed cord underwent
a certain amount of histolysis and cytolysis with more or
less scar formation, thus resembling very much the condition
found in spina bifida in man. At the conclusion of Hertwig’s
paper he rightly asks whether it is not possible for chemical
substances in the blood, alcohol, toxines or doses of medicine,
to pass from the uterus to the ovum in man and produce
monsters. It is clear that he believes that monsters are not
germinal and hereditary, but that they may be produced from
every normal ovum through influences in its environment.
Schaper® has shown us, by producing anencephaly in tad-
poles by mechanical means, that the rest of the animal grows
normally without the presence of a brain. In fact, only the
spinal cord degenerates after the brain has been removed.
The experiment of Schaper has been further extended by
Harrison,’ who removed only the spinal cord, leaving the
brain, before the spinal nerves are formed. In these experi-
ments also the tadpole grows normally without a spinal cord
or spinal nerves unless the operation interferes with the devel-
opment of the lymph-heart, when dropsy follows. Harrison
produced similar results in embryos in which the action of

°Schaper, Jour. Bost. Soc. Med. Sci. 1898, and Roux’s Archiv, VI,
1808.

"Harrison, Amer. Jour. Anat., III, 1904.

38 MALL. [Vov. XIX.

the whole nervous system is thrown out by means of acetone-
chloroform. The animals remain perfectly motionless and
also develop dropsy, due probably to the effect of the acetone
upon the heart of the animal. As I have mentioned above, .
Knower has shown that simple enucleation of the heart
anlage causes an embryo to grow without a heart, which
always has more or less dropsy, especially of the pronephros,
while those in which the nervous system only has been re-
moved are not thus affected. Therefore, when the nervous
system is paralyzed by the action of acetone, which also
retards the action of the heart, we must conclude that the
dropsy of the embryo is due to the deranged heart and not
to the damaged nervous system.

In their experiments, Panum and Dareste occasionally ob-
tained spina bifida in chicks, not including those monsters in
which the brain was deformed. Some time later Richter®
found three cases of spina bifida among several hundred hens’
eggs upon which he experimented. Otherwise these chicks
were quite normal and no amniotic bands were found. This
last point was considered to be of great importance, but now,
since monsters are produced in animals without an amnion,
it would be well, it seems to me, to relegate the amniotic theory
of the production of monsters into the class into which that of
maternal impressions has fallen. In Richter’s cases, how-
ever, the spina bifida was more or less associated with anen-
cephaly, and there were also specimens of exencephaly as well
as a few of spina bifida occulta. In other words, the condi-
tions here were more complicated than those found in the
frog.

In my own specimens of human embryos there are at
least twelve good ones of spina bifida. These are among
163 pathological ova, or about one case of spina bifida in
every 200 pregnancies. Acording to Panum’s table, there
were 38 specimens of spina bifida among 404 monsters, or
again about Io per cent. If one monster results from every

*Richter, Anat. Anz., III, 1888.

No. 1.] ORIGIN OF HUMAN MONSTERS. 390

hundred pregnancies, as my tables indicate, we then have one
foetus with spina bifida in 1,000 pregnancies, which is also
Koch’s? proportion. In other words, five young embryos
with spina bifida are aborted early, while one goes on to full
term or may live after birth.

The smallest embryo with spina bifida in my collection is
2.1 mm. long and in general appears normal. However, the
brain is atrophic, is quite wide open and may be considered
anencephalic. The cord below is also wide open, wider than
in other embryos of this age which have been described. A
similar but a little larger embryo has been described by Tor-
neau and Martin (Fig 1, Plate I). Their embryo is 8 mm.
long, apparently normal in form, with the spinal cord below
wide open. Sections of the specimen showed that the spinal
ganglia are present, lying on either side of the motor roots,
which nearly encircled the chorda. There is also some
histolysis of the cord. No. 189 is a case of complete spina
bifida with marked histolysis and destruction of the superior
end of the central nervous system.

The other specimens given in the footnote on page 27
show a variety of forms of spina bifida of the cord, probably
the most interesting being No. 293, in which there is histolysis
of the membrana reunions behind. A specimen like this may
represent an early stage of spina bifida occulta. Otherwise
the remaining specimens show a considerable destruction of
tissues, both mesodermal and nervous, which makes them cor-
respond more with the cases found at birth. Here the nervous
tissue is quite vascular, often forming peculiar tissues, such
as Von Recklinghausen? has pictured.

Recently Voigt?! has described a case of cervical spina
bifida in an embryo 18 mm. long, which was aborted fifty-
four days after the last menstrual period. A much more satis-
factory account of several specimens is given by Fischel’? in

°*Koch, Beitrage zur Lehre von Spina Bifida, Kassel, 1881.
Von Recklinghausen, Virch. Archiv, 105.

“Voigt, Anatom. Hefte, XXX, 1906.

“Fischel, Ziegler’s Beitrage, XLI, 1907.

40 MALL. [Vor. XIX.

his study of anomalies of the central nervous system in young
human embryos. Fischel describes a case with multiple but
irregular canal formation, which cannot possibly be viewed
as a case of arrest of development. His other specimen is
an embryo 10 mm. long, obtained from a woman who was
perfectly healthy and aborted for unknown reasons. This
embryo was apparently normal in every respect, with the
exception of a well marked dilatation of the cord below just
opposite the root of the leg. There was histolysis of the cord
and the embryonic skin just over the hydromyelia, which
Fischel believes indicates that spina bifida is preceded and
caused by hydromyelia, that is, he accepts Morgagni’s theory.
At any rate, the great variety of malformations of the spinal
cord which are grouped under the name of spina bifida cannot
all be likened directly to Hertwig’s spina bifida in amphibia,
although in both there is considerable histolysis. Fischel’s
specimen, which is a very important one, shows conclusively
that there is a destruction of tissues in the formation of spina
bifida much the same as I have noted in the description of
some of my specimens. In other words, the embryo was
normal before it developed spina bifida. The relations of
hydromyelia to spina bifida, and of hydrocephalus to anen-
cephaly, have been discussed so much since the time of Mor-
gagni, and my cases, as well as Fischel’s, throw no new light
upon the subject. Dropsy of the cavities and tissues of the
body accompanies practically all pathological changes in the
embryo, and it may be considered an effect just as well as a
cause in these cases of spina bifida.

Embryo No. 6 shows an interesting condition in the lower
part of the spinal cord similar to the first case described by
Fischel. There is a marked vesicle coming off the cord be-
tween the motor roots of the two last spinal nerves, as may
be seen in the illustrations. The lower end of the cord ex-
tends somewhat beyond the -vesicle. The vertebral column
ends just above the vesicle and is composed of two cartilages.
Bardeen'* has shown that the double arrangement of the last

*Bardeen, Amer. Jour. Anat., IV, 1905.

No. 1.] ORIGIN OF HUMAN MONSTERS. 41

cartilage of the cord is of quite common occurrence among
the normal embryos of my collection. I have looked through
the normal embryos of about the same stage as No. 6, and in
no instance have I found one with a vesicle like it attached.
Among the specimens two occur with very small vesicles at
the extreme tip of the cord, this being best marked in No. 22,
an embryo 20 mm. long. Another embryo, 19 mm. long,
No. 220, also shows this dilatation. It seems to me that in
these cases there is only a slight exaggeration of the normal,
while in No. 6 the vesicle is newly formed.

While the per cent of cases of spina bifida among patholog-
ical embryos and fcetal monsters is about 7 per cent of the
total number of monsters in each case, it rises in anencephaly
to about 20 per cent, that is, in 1,000 pregnancies there are 15
cases of anencephaly aborted very early and one case goes on
to full term.

Among the embryos with changes in the brain that indicate
the beginning of anencephaly there are many varieties of
deformed brains that are exposed more or less. The brain
may be escaping from the front of the head, the mid-brain
may be exposed, or the medulla is distended and fills the
whole atrophic head, as the various figures show. In most
of the specimens there is a marked histolysis of the surround-
ing tissues as well as of those of the brain, with vascular
metamorphosis of the brain tissue, as is shown in specimens
like Nos. 364 and 365. In these cases we cannot speak of a
simple arrest of development only, but also of a destruction of
tissue, histolysis and necrosis, or parenchymatous inflamma-
tion, as Panum would call it. These specimens are discussed
sufficiently under various headings further on, and under the
descriptions of the embryos in the last portion of this paper.

It has been shown that typical spina bifida and anencephaly
can be produced in a number of species of amphibia by Mor-
gan’s experiment, that is, by cultivating the eggs in dilute
solutions of NaCl. This causes an arrest of development of
the embryo, which is decidedly more marked in the central
nervous system than elsewhere. There is also a more or less

42 MALL. [Vor. XIX.

marked histolysis of the cord and brain. Similar changes
can be produced in birds, while in man the number of cases
of spina bifida and anencephaly are at least ten times as
numerous in the embryo as in the fcetus.

In man, however, the pathological changes in the embryo
are very marked and complicated by an arrest of the develop-
ment of the heart or by its complete destruction. In my
specimens no doubt the destruction of the heart must be held
responsible for the general cedema and the marked histolysis
of many of the tissues, including those of the brain. It may
be that the faulty implantation of the ovum affects the heart
first and that the changes in the nervous system are produced
secondarily, but our data are too meager to allow us to draw
any conclusion regarding the sequence of events. At any
rate, there must be other factors at work which make the
process more complicated than it would be if there were
only a simple arrest of the development of the spinal cord.
The other changes are in the region of the spinal cord and
canal and aid in producing the various forms of spina bifida,
including spina bifida occulta, which are found in the fcetus
and at birth.

In some instances, in which the individual lives after birth,
the primary change must have been of a slight degree to begin
with, and the faulty implantation of the ovum must have been
corrected, or in case the ovum was poisoned, the disease must
have been eliminated in order to allow the embryo to continue
its development. However, very simple or uncomplicated
cases must be very rare, for spina bifida is usually accom-
panied with other malformations, as is the case with most
monsters.

No. 1.] ORIGIN OF HUMAN MONSTERS. 43

MonstTERs IN Wuicu Tissues Must Have BEEN DESTROYED
—MacGnesium MONSTERS, CYCLOPIA AND CLuB-FOoT.

It has been repeately noted by experimental teratologists
that, whenever the malformation of an embryo is slight, there is
a general retardation of development of the whole body which
is more marked in some portions of the embryo than in others.
Thus it is stated that the tail of an embryo is atrophic, or
even club-shaped, a condition which cannot be brought about
without some destruction or rearrangement of its tissues.

In the human embryo there are all gradations of form
between typical anencephaly, atrophic head and deformed
head; in fact, pure types are rarely seen. These varieties can
be brought together under the general heading of atrophic
heads. The tissue change in them ranges from histolysis to
dissociation or even to maceration. In a general way the
following table gives the frequency of variations of path-
ological embryos and of monsters per 100,000 pregnancies.
The figures from which the table has been constructed will be
found on pages 26, 27, 65 and 66, and may be considered to
be fairly reliable:

Peepasvcics! Births. Normal Embryos Pathological Monsters.

and Foetuses. Embryos.
100,000 81,000 12,000 7,000 615
Bly CrOCepnaltiSe orcs Weise. at ses reuse “pr EO)
BPO cidde de eae a. rcle cc Mit arn chee ss 953 Aas
JENS OR S200 ae ie oe ae oe ng 574 119
“3 [Cand 10 ae a ee 410 47
ACEsCGIOEIMIEM: sc, 4. 6ilS.2 5,0 omen wie 697 96
Wetormed Cvesnne an tac ea sce 123 25
Metonmneds extrenuties! 22 °....0./.5 2. «'s 697 ELS

The figures given under monsters are actual figures, those
for hydrocephalus, etc., being from Panum, in which the
total number is 618. This is practically equal to the 615 which
I have obtained from various authors. My data, which are
from 163 pathological ova, were multiplied by 41 to bring

44 MALL. [VoL. XIX.

them up to the total estimated number of pathological ova
per 100,000 pregnancies. “Deformed heads” I have paralleled
with “hydrocephalus,” but I do not mean to infer that one is
directly related to the other. Otherwise the subdivisions
coincide. It is remarkable that in each instance there are
about six of a given variety of embryonic monsters for each
at full term. At any rate, the constancy of the ratios speaks
volumes in favor of the genetic relation of monsters to path-
ological embryos.

In my collection there are five specimens of exomphalos
(Nos. 115, 162, 166, 244 and 364), mostly in very young
stages, in which there is an extreme degree of atrophy ot
the embryo. It is a question whether any of these embryos in
which the atrophy is so extreme could possibly have lived much
longer, for in them the body of the embryo is nearly de-
stroyed.

In many of the specimens there is a marked distention of
the central nervous system, and it would probably be more
to the point if they had been classed with hydrocephalic
monsters. The frequency with which hydrocephalus and
dilatation of the embryonic nervous system are encountered
makes it questionable whether anything is to be gained by
the comparison.

As Giacomini has pointed out, the amnion is sometimes
partly destroyed or is wanting entirely. More often, how-
ever, there is hydramnios, as is also the case with monsters.
The excessive secretion of fluids into the cavities of the body
and into the amnion is often accounted for by a supposed
interference with the circulation, and this theory is supported
by removing the heart in young tadpoles (Knower’s experi-
ment), which is always followed by general dropsy.

To come back to the deformed heads, in which there is not
only an arrest of development, but also an actual destruction
of many of the tissues, the head is more or less necrotic or
stubby, often the brain is exposed, either in front or over the
mid-brain, or the whole brain may be wanting. In some
cases the lumen of the brain communicates directly with the

No. 1.] ORIGIN OF HUMAN MONSTERS. 45

exterior of the body, the edges of the opening often being
rounded, that is, there has been an attempt to repair the
wound. In other instances the whole brain has been de-
stroyed and the medulla is markedly dilated and fills the
whole of the stumpy head. In such specimens the face is more
or less deformed and may be adherent to the thorax below
without an intervening neck. So, with destruction of tissue,
there is a slow and continued growth, for if there were not
the chin and thorax could not have united.

There are all kinds of deformities of the face, from a simple
atrophy, in which the external features are obliterated, to
atrophic jaws, deformed or closed mouth, hare-lip, absence
of the neck, or ears, which are not developed, are deformed,
pointed or displaced. Such changes could not take place
without a marked destruction of tissue and an attempt at
further growth, which is necessarily irregular. Probably the
most pronounced of all deformities of the face are those asso-
ciated with the eyes, and my collection contains one specimen
without eyes (No. 285), one with the eyes deep in the head
(No. 135), and one with cyclopia (No. 201). The last
belongs to the wonders among monsters, which has interested
the thinking world for centuries.

In cyclopia the eye is in the middle of the face, is often
partly double, the nose is above the eye, and the cerebrum is
atrophic and usually single. Teratologists are in the habit
of holding the single brain as primarily responsible for the
condition, and I think they are right. We have seen repeat-
edly that the central nervous system suffers very frequently
in pathological embryos, and a slight atrophy or destruction
of the front of the brain in an early stage (like No. 12)
might easily end in cyclopia. We cannot admit, however,
that the tendency to produce cyclopia exists in the ovum, nor
that a close-fitting amnion did the mischief, as there is no
evidence for these theories, and the facts are against them.
If, however, the brain is malformed and the lack of correla-
tion of growth of the parts does not push the frontal process
down rapidly enough, the eyes move towards each other and
unite. All this has been proved experimentally.

46 MALL. [Vor. XIX.

Ten years ago Born,! in making numerous experiments
upon frogs’ eggs, occasionally produced cyclopia by splitting
the head through its sagittal plane after the medullary plate
is formed and then readjusting the halves. They united at
once, but in a few instances a double eye was formed. Later
Spemann? made similar experiments, and he also produced
cyclops embryos. In some of Spemann’s experiments Triton
eggs were ligated in the sagittal plane during segmentation,
and frequently embryos resulted with double heads, one or
both being cyclops. He believed that this experiment proved
that the anlage for the cyclops eye was defective from the
beginning and is not produced by concrescence of two anlages.
Levy? also produced cyclops embryos by cutting off the front
of the head of Triton larve. In the course of two weeks
the two eyes approached each other and formed a double eye,
but they were not fused; the pigment layer became destroyed,
or at least was absent at these points. The two optic cups
touched each other.

A year ago Harrison produced a new variety of cyclopia
by removing the entire brain from frogs’ embryos. The eyes
moved to the back of the head in these specimens and appeared
to unite into a single vesicle in the region usually occupied
by the pineal eye. By pricking the extreme anterior end of
the embryonic shield in Fundulus eggs Lewis found, in 1905,
that many of the eggs developed into cyclops embryos. All
stages of eyes were formed, from a double eye, and hour-glass
eyes with two lenses, to oblong eyes with either two lenses
or a single lens. The optic cups blended absolutely, thus
proving the mode of development in these eyes. Lewis
also found that in many of the embryos the brain had not
been injured at all, but the prick had destroyed the nose only.
This experiment shows conclusively that it is the absence of
tissues between the eye anlages that allows them to come

*Born, Roux’s Archiv, IV, 1897.

*Speman, Roux’s Archiv, XV, 1903, and Zool. Jahrbiicher, VII,
Supplement, 1904.

"Levy, Roux’s Archiv, XX, 1906.

No. 1.] ORIGIN OF HUMAN MONSTERS. 47

together and unite, and that a rudimentary brain is unneces-
sary. The experiments of Harrison and of Lewis have not
been published, and with their permission I have made this
note of them.

Finally, since the above was written, the remarkable ex-
periments of Stockard,* of New York, made their appear-
ance. Stockard found by placing the eggs of Fundulus into
a solution of MgCl, that 50 per cent of them develop cyclopia.
In them the two optic cups wandered towards each other and
united, much as was the case in Lewis’ specimens in which the
embryonic shield had first been pricked. The union of the two
cups formed a large compound cup, which in turn derived its
lens from the epidermis immediately over it in the middle
line of the embryo. How the magnesium acts upon the
embryo is not clear from Stockard’s description. No doubt
it will be found that it retarded the growth of the frontal
process much as is the case in Lewis’ experiments. How-
ever, the salt acted also upon the whole body of the embryos,
for their development was retarded, making them smaller than
usual, and their circulation was feeble, but they did not die.
In them, as in Lewis’ experiments, the growth of the brain
was normal.

The remarkable experiments of Stockard set at rest all
germinal theories of. cyclopia, and prove that every egg has
in it the power to develop cyclops monsters.

At any rate, these experiments, as well as the numerous
pathological embryos with deformed heads and faces, prove
that there is an extensive destruction and shifting of tissues
in the formation of monsters. This is also well illustrated
in the production of club-foot in the human embryo. It has
frequently been noticed that tadpoles whose development had
been arrested formed stubby or club tails and fins, a condi-
tion that corresponds well with club-shaped extremities in
man. In my collection there are eighteen embryos with de-
formed legs or feet, ranging from the very earliest period

‘Stockard, Roux’s Archiv, XXIII, 1907.

48 MALL. [Vor, XIX.

until the foetus is well formed. The leg bud is filled with con-
densed mesenchyme and is irregular in shape, sometimes being
stubby on one side of the body and normal on the other. The
study of the larger embryos shows that there is a kind of
“inflammation” in the deformed extremity, there being an
“infiltration”? of cells, which is especially well marked in the
tendons and around the cartilages. In general, this condition
may be accounted for by a general arrest of development due
to impaired nutrition. At any rate, embryos that are not
developing well, experimental larve, and human embryos with
other malformations, often have club-shaped arms, legs, fins
and tails.

PATHOEOGICAL OVA:

As we pass up the vertebrate scale it becomes more and
more difficult to ascertain the primary causes which produce
pathological ova, and prestmably monsters. In fact, the
causal study of teratogenesis has been and still is one of the
capital problems in medicine which is gradually being solved
by anatomists. It has been stated repeatedly in this paper
that the missing link to complete the chain of evidence is to
be found in the careful study of aborted ova which are found
to be more or less diseased. In the excellent monograph by
Granville’ we find a report of the study of forty-five aborted
ova, from which he concludes that the chorion is first diseased,
which naturally results in retarding the growth of the embryo.
He notes that an inflammatory condition must have been
present in the uterus, for the abortion of pathological ova is
usually accompanied with great pain and an excess of hemor-
rhage.

I have been unable to obtain valuable data regarding the
condition of the uterus in early abortions from pathological,
gynecological or obstetrical literature. It is all clouded in

"Granville, Graphic Illustrations of Abortion, London, 1834.

No. 1.] ORIGIN OF HUMAN MONSTERS. 49

mystery, and one finds an endless contradiction of opinions.
It seems to me that a study of the norm, uterus and chorion is
required before much headway can be made. In my opinion,
this is possible only in some great clinic which has attached to
it a first-class laboratory manned by able investigators. How-
ever, for the present, we must do the best we can with the
data at our disposal. First, I shall quote from several com-
petent recent writers.

Ahlield states in his treatise on obstetrics? that many abor-
tions are due to endometritis, which produces inflammatory
adhesions of the placenta and membranes; hypertrophy of the
decidua is associated with abnormal forms of the placenta,
which is followed by an arrest of the development of the em-
bryo. Furthermore, atrophic endometritis is commonly fol-
lowed by the formation of an atrophic decidua, which in turn
must retard the growth of the ovum. In addition to these
forms there is a condition known as hemorrhagic endome-
tritis, due to a variety of infections. The hemorrhages which
take place in the chorion or placenta are often accompanied
with bacteria or may be due to nephritis, which may be fol-
lowed by decidual infarctions and death of the embryo. In
these cases the effused masses of blood are in successive layers
of old and new clots, forming a tumor known as decidua tube-
rosa. In case the bleeding continues after the death of the
embryo the chorion may be converted into a fleshy mole.

Ahlfeld further states that repeated abortions are due to
endometritis or to syphilis, but the second abortion need not
by any means be due to the same cause as the first. If due to
syphilis successive abortions occur later and later in pregnancy.
Syphilis, and possibly gonorrhoea, causes abnormal develop-
ment of the decidua; in chronic endometritis the decidua
undergoes diffuse hypertrophy. According to Virchow, syphilis
causes knotty development of the decidua in case the mother
is infected; in case the father is infected the primary change
is found in the chorion.

*Ahlfeld, Geburtshilfe, 1903.

50 MALL. [Vor. XIX.

According to Williams* “the death of the foetus is fre-
quently due to abnormalities in the development of the em-
bryo which are inconsistent with feetal life. More often, how-
ever, it results from changes in the foetal appendages, which
interfere with its nutrition, such as excessive torsion of the
cord, producing hydramnios, hydatidiform mole or syphilis.

Abnormalities of the generative tract likewise play
an important part in the etiology of abortion. ‘Thus develop-
mental anomalies of the uterus, or imperfect development of
the normally formed organ, may be responsible for conditions
which are unfavorable for the implantation of the ovum and
later for the development of the placental circulation. Chronic
metritis is supposed to act in the same way. . . . The
most important factor in the production of abortion is af-
forded by diseases and abnormalities of the decidua. In
hypertrophic forms of decidual endometritis—decidua poly-
posa—the bulk of maternal blood brought to the placental site -
goes to nourish the hyperplastic decidua, while in the atrophic
forms the conditions are unfavorable for the normal implan-
tation of the ovum and the development of the placenta. More
important still is the part played by chronic glandular endo-
metritis and acute inflammation of the decidua. The former
is usually acompanied by hemorrhagic changes, and is the
most frequent cause of abortion in the early months.*

I gather from conferences with competent scientists of large

*Williams, Obstetrics, New York, 1903, p. 522.

*Marchand, writing on moles, says in Eulenberg’s Encyclopedia,
Vol. 15: “Abortives Ei ohne Spur eines Embryo oder mit mehr oder
weniger unbekanntlichen Resten derselben. Ein sehr haufiges Vorkomm-
niss bei Aborten, welche wohl in den meisten Fallen durch frithzeitige
Unterbrechung der Ernahrung infolge beginnender Losung des Eies von
der Uteruswand, Blutungen in der Decidua basalis und capsularis oder
durch vorausgehende Erkrankungen der Uterusschleimhaut bedingt ist.
Zuweilen findet sich ein kn6tchenfOrmiger Rest des Embryo an der
Innenflache oder ein Rest des Nabelstranges oder eine mit Fltssigkeit
gefiillte Blase. Ist der Embryo nicht vollstandig zu Grunde gegangen
und erfolgt die Ausstossung des Ejies nicht, so kénnen anderweitige
Missbildungen die Folge sein. Bei der Ausstossung findet man die Decidua
basalis und capsularis mit Blutextravasaten durchsetzt (Blutmole).”

No. 1.] ORIGIN OF HUMAN MONSTERS. 51

experience that “uterine scrapings after abortion rarely show
signs of endometritis, although they contain many leucocytes
and characteristic masses of fibrin. When the abortions from
one woman are frequent she is undoubtedly syphilitic.” An-
other argues that endometritis rarely shows the presence of
inflammation, and states further that inflammation of this
organ is usually confined to the cervical canal. Still another
states that endometritis, which is a rare affection, is usually
due to the gonococcus or sometimes to an acute infection. At
this place it may be pertinent to state that pathological ova
and monsters, which are quite frequently found in other
mammals, cannot be due to syphilis or gonorrhcea, but are
often accompanied with a peculiar kind of separation of the
chorion. In such specimens a large mass of mucus and no
blood encircles the ovum, and from all indications the embryo
has died suddenly, for it is not deformed. It is not necessary
to introduce more opinions, for they will not lead us nearer
to a solution of the problem. For the present, the opinions as
expressed by Ahlfeld and by Williams are the best at our
disposal. Both are able scientific obstetricians, Ahlfeld being
in addition a teratologist, and Williams a leading obstetrical
pathologist.

It is well known that a woman who aborts a pathological
ovum or gives birth to a monster will probably abort again,
and runs a greater chance of giving birth to a second monster.
Teratologists are inclined to read these facts in favor of the
germinal origin of monsters, which may even be hereditary.
Since there is no recorded case of a woman giving birth to
a second polysomatous monster, while there are numerous
cases in which women bore second merosomatous monsters,
we can as well consider the former as “accidental” and the
latter as due to some change in the uterus and not inherited
through either the germ or the sperm. (Certain varieties like
those of the extremities and anatomical anomalies must be

. excluded from this discussion, for they are known to be ger-
minal and are hereditary.) To be sure, we cannot exclude
the possibility of a certain per cent as being germinal, that is,

4

52 MALL. [Vor. XIX.

there was some change in either of the germs before fertiliza- -
tion took place. On the other hand, experimental work on
amphibian, fish and bird embryos shows that monsters can be
produced with ease from perfectly normal fertilized eggs. In
general the methods employed by experimental teratologists
is to subject the eggs to various insults which affect the nutri-
tion and impair the growth of the embryo. If now a similar
condition can be found to exist for human pathological ova
which corresponds with those the experimental teratologist
produces, the point is proved, that is, many merosomatous
monsters may be formed by placing normal ova into an un-
favorable environment. All of our experience in teratogeny,
if read aright, indicates that the normal ovum got into a
diseased uterus did not implant itself well, and the consequent
impairment of nutrition produced a monstrous embryo.
This hypothesis, which will be proved to be correct under
the heading of tubal pregnancy, explains fully the presence of
so many pathological embryos in multiple abortions and the
apparent germinal origin of merosomatous terata like spina
bifida and anencephaly.

His,® in the discussion of normal and abnormal embryos, is
rather of the opinion that pathological embryos are due to
primary changes in the germ, and that their abortion naturally
takes place because such ova act as foreign bodies in the
uterus. In some instances, however, he excludes the possi-
bility of the primary cause being due to an interference with
their development, such as may be brought about by deficient
nutrition, lack of oxygen and mechanical influences due to the
uterus being displaced. Later,® in a discussion of open ques-
tions in pathological embryology, he seems to be inclined to
abandon the theory of the germinal origin of pathological ova
altogether, for the examination of several specimens showed
that the changes within them were of a secondary nature.
They indicate that the embryo is in process of dying, that

"His, Anatomie menschl. Embryonen, II, 1882.
*His, Virchow Festschrift, I, 1899.

No. 1.] ORIGIN OF HUMAN MONSTERS. 53

is, the tissues of an embryo as normally formed have become
swollen, are disintegrating and strange cells are wandering
through them. In His’s opinion such changes cannot be
viewed as primary, but rather as secondary conditions.

The other student of pathological embryology, Giacomini,’
emphasizes the necessity of studying the form and structure
of the decidua in normal as well as in pathological ova, for
at this point mechanical and nutritive influences must occur,
which are of prime importance in the production of early path-
ological embryos. He predicted that such a study, together
with experiments upon lower animals, would ultimately ex-
plain the origin of monsters.

There is one more opinion, from the hundreds upon this
subject, which I must not omit. It is from O. Hertwig,’ in
his more or less general article on the production of spina
bifida in Axolotl. After stating that a .6 per cent solution
of NaCl will produce spina bifida in frogs and a .7 per cent
solution will produce the same kind of monster in Axolotl, he
asks whether it is not possible that some similar method is
employed by nature to produce spina bifida in man? Is it
not possible for chemical substances in the blood—as alcohol,
toxines or medicines—to pass from the uterus to the ovum
and make it monstrous? Evidently he believes that the power
to become monstrous is not inherited, but is due to external
influences.

It is extremely difficult, if not impossible, to prove directly
that the primary changes which produce pathological ova are
in the chorion and not in the embryo. I find in glancing over
the tables which follow, with the discussion of the individual
specimens, that among 143 pathological specimens but fifteen
appear to have a normal chorion, and that in thirty-five the
chorion is sufficiently infiltrated with leucocytes to indicate
that some inflamamtory process was present in the uterus. In
all of the specimens excepting the fifteen in which the chorion

"Giacomini, Merkel u. Bonnet, Ergebnisse, IV, 1804.
*O. Hertwig, Gegenbaur’s Festschrift, II, 1896.

54 MALL. [Vou. XIX.

appears to be normal all kinds of secondary changes have
taken place. The mesodern is fibrous, hyaline or cedematous,
the villi are atrophic, hypertrophic or missing altogether, and
the syncytium is irregular or necrotic, and sometimes it has at-
tacked and invaded the mesoderm of the chorion. The decidua
when present is usually infiltrated with leucocytes, which often
accumulate in great masses, or often form abscesses. All this
could take place if the embryo had died and the ovum had
continued to grow, but on account of the presence of a dead
embryo the uterus reacts as if it had a foreign body to expel.
In fact, most of these changes just enumerated probably took
place long after the embryo had become monstrous, and we
are no doubt treating with the primary process, much intensi-
fied by the presence of a pathological ovum. The final proof
in favor of the theory that these changes are primary will be
given under the discussion of tubal pregnancy.

It will be noticed that the “normal” chorion is most com-
mon in young ova, that is, before the process of destruction
has been under way for a long time. In an earlier publica-
tion? upon this subject I was much inclined to the idea that
the primary difficulty in a pathological ovum is to be sought
in the embryo, but later’? I formed the specimens into two
groups: (1) Those in which the primary cause lies in the
embryo, and (2) those in which it is outside of the chorion.
This gradual change of my ideas is identical with that which
both His and Giacomini passed through, for all of us based
our conclusions upon a simple morphological study. The
morphologist must be very careful in the arrangement of his
sequences, and I think it is to our credit that we have been
so. But now, since we have experimental teratology and a
more careful study of the gynecological history of the speci-
mens to fall back upon, it seems to me that the solution of
the problem is at hand.

The ova which appear to be normal, but have within them
deformed embryos, or none at all, are the ones that require

*Mall, Welch Festschrift, J. H. Hosp. Rep., IX, 1900.
*Mall, Vaughan Festschrift, Ann Arbor, 1903.

No. 1.] ORIGIN OF HUMAN MONSTERS. 55

our most careful consideration, for in them we are to find
the first pathological changes. In studying the villi of the
chorion in these specimens I tried to remain on the safe side
when I stated that they were fibrous or cedematous, and no
doubt erred correspondingly when I stated that others were
normal in structure. In the course of time I found that in
most chorions which were markedly pathological a stringy
mass of fibrin or mucus more or less rich in leucocytes was
found between the villi. In specimens undoubtedly normal and
containing a normal embryo this stringy mass was never
found. Occasionally a stringy mass was found between the
villi in ova which appeared to be perfectly normal. A good
example is found in an ovum which appeared perfectly normal
with the exception of a lateral pouch to it, containing an em-
bryo four millimeters long which is slightly deformed’? (No.
80). Sections of the villi show that they are perfect in form.
and in structure, being covered with a well-developed syncy-
tium. Between the villi there are strands of a fibrin-like mass,
in which there are imbedded a number of leucocytes. Another
specimen which has been described by.me as a normal one
contains a similar substance between its villi‘? (No. 12). In
this specimen there is an unusually well developed magma
reticulé and the head is underdeveloped. The neural tube
is wide open at both ends, and it seems to me that its form
is not quite normal. It came from a woman twenty-three
years old who had been pregnant twice, aborting both times.
Two other specimens may be mentioned, one which I have
also described as a very young normal ovum because I knew
that the abortion had not been a natural one.** The woman
had had a continuous hemorrhage for seven days before the
abortion, and since then I have learned that the detachment of
a normal ovum for a much shorter time than seven days is

“Mall, Johns Hopkins Hospital Reports, IX, Fig. 80.

"Embryo No. 12, Journal of Morph., X, 1897, Arch. fiir Anat., Suppl.
Bd., 1897, Johns Hopkins Hospital Reports, IX, Fig. 12.

®No. 11, Anat. Anz., VIII, 1893, Journal of Morph. X, and Johns
Hopkins Hospital Reports, IX, Figs. 14 and 15.

56 MALL. [Vor. XIX.

sufficient to cause an embryo to become monstrous. Specimen
No. 250 of this communication is about as old as No. 12,
only it is slightly more deformed. It had been removed with
a curette from a woman who was suffering from uterine
trouble. The decidua which encircles the ovum is well infil-
trated with leucocytes, showing that the decidua was inflamed.
These four specimens are representative. One was detached
by mechanical means, one was removed by a curette on ac-
count of endometritis, and two were spontaneous abortions
of ova which appeared to be normal but contained a stringy
mass between the villi. This condition is usually well marked
after the chorion has undergone radical changes and is well
infiltrated with leucocytes, which often form into smail
abscesses.

In the following table I have brought together all of the
pathological ova in my collection in which there is any history
of the women from whom they were obtained. Positive as
well as negative histories are given:

A glance at this table shows that in eleven cases the main
trouble preceding the. abortion was a severe hemorrhage ex-
tending over a number of days. In a second set of twelve
cases the abortions were from first pregnancies in women
newly married or who had been married for some time and
were anxious to have children. In the third group of ten
cases the women had given birth to a number of children and
then began to abort, often a second or third time. . The first
group need not be considered further, but the second group
consists of women who are naturally sterile and abort when
they become pregnant. The third group of ten cases is more
easily understood. The women, perfectly healthy, gave birth
to one or more children and then conceived but aborted quite
regularly. In these cases we must admit that the uterus was at
first perfectly healthy and the ovum was normal, but later, due
to a variety of infections, the uterus became “inflamed,” and
thereafter the fertilized ovum could not implant itself, became
pathological, and later was aborted. According to the data
given, seven of the mothers were healthy and twelve had uter-

57

and

No. 1.] ORIGIN OF HUMAN MONSTERS.

No. Condition of Mother. pice Remarks.

tr |Apparently normal. Some |Hemorrhage for 7 days.

12 | Married 3 years. None |Two abortions.

FiDI™ lke versie: atauereyevetey siete Marenstere re ete carmiers ? |Hemorrhage 4 days.

Cf die Waicace SOR NCP REDROR ICN ets Oe ocean ee ee .|First pregnancy.

WO. Nedcesath crass Gr.cyec'jatc, Realy ous tere tages cat's 1 |Great flooding.

71 |Chronic cystitis and endome-| None |First pregnancy, gave birth to
tritis. a child a year later.

17 aE Re aM EY SUS ie MOT oe lene aR) NRE ....---| Hemorrhage for 12 days.

11o | Uterus large and retroverted 9 |Hemorrhage 5 days. See No.
I4t.

Speen el ater etaehsterale ter tags eis tO -| Hemorrhage 8 days.

¥93) (Perfectly normale 0 et aie de Hemorrhage 8 days.

TAG Ate Wate rey toavss ary Merete tats vores n ial." aistsoye Lives sa em Mechanical injury to ovum.

141 | Uterus large and retroverted 9g |See No. rro.

PAD ea| Weick horsiacsvone Ohoaye. sVayahe ave Sis soar 3 |Hemorrhage 4 days, third
abortion, one 3 mos.,
one 20 mos. ago.

152 |Endometritis, Some |Third successive abortion,
each time in third month.

159 |Perfectly healthy father and) None |Married two years. This is

mother. No indication second abortion at third
whatever of endometritis. month. Repeated hemor-
rhage during pregnancy.
Anxious to have child.
161 |Purulent leucorrhcea. Had| ?
tube introduced 4 weeks
before abortion.

162 |Not the slightest indication of} 5 |Bleeding for two weeks before

uterine disease. abortion.

205 |Syphilis suspected. None | Married three months.

209 |30 years old. ? |Three years ago miscarriage in
third month and 3 months
ago gave birth to a monster.

DOW erate eee ne ee eee ee a ain Bpuw'|. os Maraties Nishelevanmanaychn cal shane eee arene

228 |Fairly healthy. None | First pregnancy.

230 |Always menstruated regularly; 3 (Three other miscarriages.

during pregnancy.

246 |Youngest child 7 years old.| 2 /|Five miscarriages, all about

Since then miscarriages. the same size as this one.

PIN OM A eee. eit eR eae vied ouch Se whe lies ? |From uterine scrapings.

252 |First pregnancy in an un-| None |Continuous picgusiar eles fora

married woman. month.

278 |Chronic endometritis. ? |From uterine scrapings,

292a)Was curetted two years ago None /|First pregnancy.

for menorrhagia.

ZO Finishes en cteyet aie eleuscaieusl oueteve’s aoe wade ? |From uterine scrapings.

ae Pm ae ety ote (er Neen aera) SO oe : \ Prom the same woman.

Sea Re eae oie NS ine Seeks. 0 None |One other abortion in eighth
month.

364 | Uterine trouble. None |First conception in a woman
anxious to have a child.

395 |Removed on account of ? |From uterine scrapings.

eclampsia.

399 | Woman a marked bleeder. None | Married ten months.

402

Subinvolution of the uterus.

58 MALL. [Vor. XIX.

ine disease. Although this division does not correspond with
the above three classes, in a general way it is suggested that
women who are called normal abort with much hemorrhage,
while the ones with uterine disease belong to the second and
third classes mentioned above. Although these data indicate
that pathological embryos are due to faulty implantation of
the ovum, they by no means prove it. All of the ova in the
third group of ten cases could certainly not have been destined
to become pathological, for they all came from women who
had given birth to healthy children. They could not attach
themselves successfully to the diseased uterus, and, due to
malnutrition or poisons which are thrown out from inflamed
surfaces, the chorion became pathological and the embryos
deformed. This point is fully proved, I believe, in the study
of ova from tubal pregnancies.

TWIN PREGNANCIES.

Especially instructive and interesting are those cases in
which two pathological ova were obtained from the same
woman. Five such sets are found in my collection which I
shall describe. The first set, Nos. 308 and 325, are from a
woman who had born two children during the previous two
years, and are especially valuable in this discussion. The
first ovum (No. 308) appeared to me perfectly normal, and
the embryo within it was not changed at all. However, the
amnion was found filled with a jelly-like mass of granular
magma, and this aroused my suspicion. Sections were
therefore cut from the placenta at the attachment of the
cord and a stringy mass rich in leucocytes was found between
the villi. They were normal in form and possibly their
mesoderm was fibrous in structure. Nine months later a sec-
ond ovum was obtained from this woman, which was de-
cidedly pathological. Both the chorion and the embryo were
much changed, as the figures and description of the specimen
will show. This case, which should be observed further, is
to be explained by disease of the uterus, which began after
the birth of the second child. This change had not gone far

No. 1.] ORIGIN OF HUMAN MONSTERS. 59

at the time of the first abortion, but was more advanced at the
time of the second abortion. (Later the woman died of
pneumonia. See history of No. 308.)

The second set, Nos. 110 and I4I, came from a woman
who had had nine children, after which she broke down in
health, about ten years ago, when she conceived quite regu-
larly, but aborted each time. The two specimens, which
are about a year apart, are much alike, no doubt due to their
subjection to the same environment. The chorions are mark-
edly changed and the embryos are macerated and very much
deformed.

The third set, No. 330a and b, are twin ova from a
woman who had aborted once before. These two specimens
show practically the same changes in the chorions and in the
embryos, as may be seen by the figures and the description.

The fourth and fifth specimens, Nos. 207 and 341, form
two sets of duplicate twins. Unfortunately, no histories
accompany either set of specimens. However, in each set the
changes within the embryos are about the same degree, but,
of course, these sets do not throw any light upon the question
whether the primary change was in the germ or in its
environment.

The history of the first three sets, however, speak decidedly
in favor of the hypothesis that the ova were normal to begin
with, and the pathological changes within them are due to
the diseased condition of the mucous membrane which sur-
rounded them. The implantation was faulty and a variety
of other complications was present to interfere with the
nutrition and growth of the embryo, which consequently
became deformed.

Very recently Dr. West sent me two ova (Nos. 384 and
419) from a woman with an undeveloped uterus of infantile
type. She had been married three years, became pregnant
twice and aborted on the fifty-fourth and on the fifty-ninth
days. The chorions are covered with degenerated villi, which
are imbedded in and encircled by much blood. Both are mark-
edly pathological and each contains a deformed embryo about
3 mm. long.

60 MALL. [Vor. XIX.

UNRUPTURED TUBAL PREGNANCIES.

It is of interest to consider together the ova obtained from
tubal pregnancies, for it is through them that light may be
thrown upon the question, if the embryo is pathological,
whether its condition is inherited or is due to the bad environ-
ment of the ovum. In case it is the former, the per cent of
pathological embryos should not be larger than those obtained
from the uterus; in case it is due to the latter, the per cent
should be increased.

It is stated by different writers that embryos are rarely
found in tubal pregnancies, but that remnants of the chorion
are often present. However, it is also stated that, in case
the tube is found ruptured and much blood has escaped into
the peritoneal cavity, the embryo may have been present, but
could not be found on account of the great quantity of blood.
On the other hand, Professor Brodel informs me that among
eleven specimens of tubal pregnancies found recorded in his
catalogue of human embryos nine contained normal speci-
mens. In my own collection seven tubal pregnancies out of
nineteen specimens contained normal embryos. It must be
remembered that as a rule specimens were sent to us only in
case the surgeons who removed them found normal embryos,
which they thought we were collecting. Considering only the
tubes that were sent to me unopened and excluding those
which were obtained from Dr. Kelly’s gynecological labora-
tory, I find among seven specimens two ova without embryos,
four with pathological embryos and but one with a normal
embryo. The other six normal embryos spoken of above
were all recognized by the surgeons as “‘normal and valuable
specimens” before they came into my hands.

Following the hint obtained by considering all of the speci-
mens which came to me unopened, I collected all of the his-
tories of the same kind of specimens from Dr. Kelly’s
laboratory. These cover a period of about ten years and are
taken from the laboratory records of over 10,000 miscel-
laneous cases. I find that altogether 128 cases of tubal preg-

No. 1.] ORIGIN OF HUMAN MONSTERS. 61

nancy were carefully described after numerous sections of
them had been examined microscopically. I have excluded
the reports of 82 of the specimens, for in them the tubes had
ruptured before the operation. Of the 46 that remain the
histories state that they were unruptured and vary from one
to six centimeters in diameter. Two of the 46 contained
normal embryos of the second month and five of them path-
ological embryos. The rest, 39 in number, contained entire
ova without embryos or simply villi of the chorion in various
stages of degeneration. Usually the dilated tube was found
filled with blood through which were scattered villi, the
chorion rarely being intact, that is, encircling the ccelom.
The chorion had collapsed, leaving scattered villi, which were
“degenerated,” “poorly formed,” or “necrotic,” in different
cases. Usually, it is stated in the record, “‘scattered villi were
found in the clot; no embryo was found.”

The normal embryos need not be discussed more than to
mention that the amnion was very small, as is usually the
case in these specimens. The pathological specimens, how-
ever, are of the same nature and degree of degeneration as
those found in the specimens obtained from the uterus. A
number of small specimens which were cut into serial sections
contained no embryos at all; they are included among the 39
mentioned above. From my experience in searching for em-
bryos in pathological ova I am of the opinion that a few
more pathological embryos would have been found had the
specimens been examined with greater care. It is unlikely
that more normal embryos would have been found, for in all
cases they lie in a ccelom or an amnion filled with a clear
fluid. I have never found a normal embryo in an ovum which
did not contain a cavity well marked by a sharp wall and
filled with a transparent fluid, and therefore think it unlikely
that those who made the sections for microscopical examina-
tion overlooked any normal embryos.

From my records not over seven per cent of uterine
pregnancies contain pathological embryos and were the pri-
mary cause which produces them located in the germ we

62 MALL. [Vor. XIX.

would not expect a higher per cent in ova from tubal preg-
nancies. Instead, we find that 96 per cent are pathological
and but 4 per cent normal (two in 46 specimens). Since this
point is of prime importance in the causal study of terata, I
have brought together all of the pathological ova I have
obtained from tubal pregnancies. These have been studied
with greater care, as a number of them have been cut into
serial sections. Most of them will be found figured among
the illustrations of this article. The following table shows
that there are 14 specimens, of which seven contain patholog-
ical embryos and six are entirely free of them. Nearly all
of the ova are very small, and in practically all of them the
chorion is markedly affected. Generally the mesoderm of the
chorion is fibrous and atrophic, the villi also showing all kinds
and degrees of degeneration. Occasionally some of the villi
are hypertrophic:

Dimen- Condition of
Number. plone or Embryo. Chorion and Remarks.
mm. mm.
5S ja12'x 6 2, Vesicular | Atrophic.
196 | 12x12 | 3, Homoge- | Atrophic—Some villi are en-
neous larged and invaded by syn-
cytium.
2098 4 None Fibrous villi partly infiltrated
with leucocytes.
324 | 45X45 aot Atrophic and fibrous. No
syncytium.
342 | 30 X 20 5 Atrophic and fibrous.
348 6, Atrophic
361 10 None Coelom filled with a dense
magma.
367 |. Tox ¥ None Villi degenerated in part.
369 7 x8 None Villi fibrous and degenerated.
378 12 None Villi cedematous.
396 7 2, Vesicular | Mesoderm and villi fibrous,
some invasion by syncytium
Plate II, Fig. 6 8 x 6 None
Plate II, Fig. 5 6 Vesicular (?)
Plate II, Fig. 7 | 60x20 II Chorion hypertrophic and em-.
bryo disintegrating.

In most instances the ccelom is filled with a dense magma
and in six the embryo is entirely wanting. The embryos in
the remaining seven are of the vesicular form in three, of

No. 1.] ORIGIN OF HUMAN MONSTERS. 63

the cylindrical form in four, and are necrotic and disinte-
grating in the remaining specimens. In general, the changes
in the chorion and embryo in these 14 specimens are the same
as in those that are obtained from uterine pregnancies. It
cannot possibly be admitted that the primary difficulty in
these specimens is to be found in the embryo itself, that is, it
is germinal, for the ova which become lodged in the tube are
probably of an average kind, unless the unreasonable stand
is taken that there is a greater tendency for abnormal than
normal ova to lodge in the tube. To take this stand it is
necessary to overlook altogether those cases in which tubal
pregnancy is due to mechanical obstruction of, or to diverticula.
from the uterine tubes. The results obtained from the study
of these 14 specimens are probably representative of all tubal
pregnancies which are examined with great care before the
tubes rupture. In the very earliest specimens there are indi-
cations of faulty implantation, due no doubt to the character
of the tissue of the tube which permits of an excessive hemor-
rhage around the ovum (e. g., No. 396). Only in rare
instances does a good decidua form in the tube, which in
these cases must be produced by the presence of a growing
ovum. However, just in these cases a decidua develops in
the uterus, although the ovum is not present there.

I have found in collecting 434 human embryos of all kinds
that 163 of them, or 38 per cent., are pathological. If we
consider that an abortion occurs in every fifth pregnancy, then
a pathological ovum is found in every twelfth pregnancy (7
per cent in the table). If anything, this number is too high,
for a number of larger normal fcetuses were not catalogued
and are not included with the total number—434. If the
data obtained -from unruptured tubal pregnancies where the
number of pathological specimens rises to 96 per cent are
compared with the pathological specimens from uterine preg-
nancies (7 per cent), it seems to me that the argument against
the germinal origin of pathological ova and monsters is over-
whelming.

The relation of the chorion to the wall of the tube or to
the mucous membrane of the uterus is well known for ova

64 MALL. [VoL. XIX.

two millimeters in diameter or larger. The two structures
become beautifully adjusted, but in the case of most tubal
pregnancies the small ova and villi float largely in a mass of
blood, are not adjusted to the decidua, and, apparently, on
account of impaired nutrition, degenerate. The syncytium
becomes atrophic, the villi become fibrous, and often leucocytes
as well as syncytial cells invade the mesoderm of the chorion.
It naturally follows that when the nutrition of the ovum is
impaired the most advanced growing point, the embryo, for
which all is adjusted, should suffer most. Thus it happens
that in many instances the chorion is not markedly changed,
but the embryo is almost entirely destroyed or is wanting
altogether. In a short time the ovum collapses, becomes an
irregular mass, and its “rootlets,” the villi, are still found
scattered throughout the blood-clot, or a small heap of them
are found poorly adjusted in a fold of the tube covered with
changed and distorted syncytium and decidua. These
conditions, found so well marked in tubal pregnancies, are also
found in uterine pregnancies, but in them it is difficult to
determine whether the degeneration of the chorion follows
because the embryo has died suddenly or has inherited the
power to become abnormal. The study of the ova from tubai
pregnancies demonstrates conclusively, it seems to me, that
the changes in the chorion are primary, and those in the
embryo secondary, due to faulty implantation of the chorion.

Another argument in favor of the view I have advanced
regarding the production of pathological embryos is obtained
by studying those embryos in tubal pregnancies which were
not destroyed at once, but which became well attached and
grew on towards full term. I mean the fate of the 4 per cent
of normal embryos found in early unruptured tubal preg-
nancies.

No. 1.] ORIGIN OF HUMAN MONSTERS. 65

RUPTURED TUBAL PREGNANCIES.

According to Williams,’ most of the ova in tubal preg-
nancy are extruded through the internal opening into the
abdonimal cavity, producing a condition known as tubal abor-
tion. He collected the cases published by various authorities,
and found that in 289 cases that were carefully reported 78
per cent ended by abortion and 22 per cent by rupture of the
tube. Among these there is a small per cent of normal
embryos, and the fate of them has recently been studied by
Von Winckel.? - Before considering Von Winckel’s report
it is necessary to collect some data regarding the frequency
of abortions of pathological ova and of monsters in uterine
pregnancies.

Williams states that ‘‘a conservative estimate would indi-
cate that every fifth or sixth pregnancy in private practice
ends in abortion, and the percentage would be increased con-
siderably were the early cases taken into account, in which
there is a profuse loss of blood following the retardation of
the menstrual period for a few weeks.” I also find that
Marchand* has collected the per cent of monsters from a
number of writers; his figures are as follows:

Beticr: Births. Monsters
WB ieeiisstetn os tis slate kink Senter Genus 22,293 132
12 E51 6) OWS) Sarr er ee ey ee er 772, 7
PIG MEWIOREL fe. 2 Sar. wate tie eo 39,917 88
MUR IIMG Se Nerney Suettart <t5 (Ghats eaprer ie 10,056 156
NIV TSS Fae ne ee as oe a 8,149 232

81,187 615

*Williams, Obstetrics, p, 539, New York, 1903.

*Von Winckel, Ueber die Missbildung von ektopisch entwickelten
Friichten, Wiesbaden, 1902.

®Marchand, Missbildungen, Eulenburg’s Real-Encyclopedia, Bd. 15,
P. 439, 1897.

66 MALL. [VoLt. XIX.

It is noticed that these data, which are given in chronological
order, give an increasing per cent of monsters, indicating
that the more recent ones are collected with greater care.
Taken together they give pretty well, I think, an average,
for no doubt slight anomalies are included only in the records
given by Von Winckel. If we assume that the number of
births represent only four-fifths of the pregnancies, the figures
will read about as follows:

Abortions Abortions
Pregnancies. Births. Normal _ Pathological Monsters
Embryos. Ova. at term.
Number ¢i22 &. 100,000. 80,572". 11,765 97,0452 015
In per cent 100 80 12 7 6

I find in my own records of 434* embryos (Catalogue Nos.
I to 404) that 163 of them are pathological, which, when
raised to the number of abortions given in the table above,
gives 7,048 as the number of pathological embryos in every
100,000 pregnancies. For the present this is as near as I can

First Month.

Nos. 1 to 208— 26 normal
Nos. 209 to 404— 18 normal

Nos. 1 to 404— 44 normal
Nos. 1 to 208— 59 normal
Nos. 209 to 404— 46 normal

Nos. 1 to 404—107 normal
First
Nos. 1 to 208— 85 normal

Nos. 209 to 404— 66 normal

and 33 pathological = 56 %
and 45 pathological = 71*%
and 78 pathological=590 %

Second Month.

and 32 pathological = 35 %
and 28 pathological = 38 %
and 60 pathological = 36 %

and Second Months.

and 65 pathological = 43 %
and 73 pathological = 53 %

of pathological
of pathological
of pathological

of pathological
of pathological
of pathological

of pathological
of pathological

Nos. 1 to 404—151 normal and 138 pathological = 48 % of pathologicai
Total Numbers of All Months.
Nos. 1 to 404—271 normal and 163 pathological = 38 % of pathological

“Total number of specimens (434) catalogued under 404 numbers.

*The per cent has been fully up to 70 from Nos. 127 to 404. The
low per cent (44) up to No. 127 is due to the fact that only norma!
embryos were at first collected. .

No. 1.] ORIGIN OF HUMAN MONSTERS. 67

approach the proper number and per cent, but it will do for
the sake of making comparisons. It appears, therefore, that
in every 100 pregnancies in cities there are seven abortions
and about one monster is born at term. It may be less in
country districts.

I have made no special effort to collect foetal monsters, but
find that my collection contains seven monsters which are not
included in the 163 pathological specimens mentioned above.

I have been unable to collect any good data regarding the
frequency of monsters in tubal pregnancy, but, according to
Joachimsthal, they are very rare, and according to Leopold
they are rare, while Martin and Orthmann, Ruge, Olshausen
and Veit state that they are more common than in uterine
pregnancies. It may be that the latter gynecologists con-
fused early pathological embryos with older monsters, while
the former did not, a line between them being difficult to
draw, and, therefore, it is not frequently recognized.

Von Winckel has done us a service in collecting those
feetuses from tubal pregnancies which continued to live and
were removed alive from the abdominal cavity. The foetuses
which he considers must have been derived from the 4 per cent
of normal embryos I have found in unruptured tubes removed
in Dr. Kelly’s clinic. Ninety-six of the specimens were so
markedly pathological and so far destroyed that they could
not possibly have lived until the end of pregnancy. Von
Winckel’s cases are especially valuable to determine the fate
of the embryos that must have been normal before the tube
ruptured, that is, during the first weeks of pregnancy.

Von Winckel first gives the cases that have been published
by others, as follows:

Date. Author. No. Monsters.

LOZOMPEVennIne FS Fis a. 150 2 and 6 compressed
foetuses.

Bod Orillard! ico. 6 (alive) 6

Loos evens |... 25112). (257. 2G

1891. Ktichenmeister ... 43 7,

5

68 MALL. [Vor. XIX.

Date. Author. No. Monsters.
PLATS itt CA as 45 II

MOOI SILEMER ae Faye tes 126 (alive) 36

TOOL Vie NVirickel:: anise: 13: (alive) ang
Aikehrer seein soe 93 (uterus

bicornis) 7

It is seen in the table from Von Winckel that the number
of monsters increases in per cent from year to year. How-
ever, he thinks that it is safe to say that one-half of
the foetuses in ectopic pregnancy are deformed, the most
common deformity being that of the hands and feet. Von
Winckel further collected 87 cases (14 his own) and found
that 57 of them were much deformed and 12 were markedly
monstrous. Among these there were six cases of hydrocephalus
and one each of hydromeningocele, encephalocele, anencepha-
lus, omphalocele, spina bifida, and hypospadia. In addition, the
head was found deformed, 57; legs, 44; arms, 35 times; with
club-feet in 12 and amniotic bands in 4 cases. The placenta
was usually deformed, sometimes multiple, broad and thin or
short and thick, and often very hemorrhagic.

In general, then, it is the poles of the body that suffer
most, the head being deformed in 75, legs in 50, arms in 40
and the trunk in 4 per cent of the cases. It is clear that a
good share of the difficulty is due to ordinary mechanical
causes, but the 12 cases that were markedly monstrous could
not be due to such causes alone. For them we must hold
the hemorrhagic placenta responsible, which could be in-
cluded under what I have termed faulty implantation. There-
fore, 14 per cent of the 87 cases become monstrous, while in
normal pregnancies it is but .6 per cent. However, in all of
100 total pregnancies the per cent would be as follows:

P ies, Births Pathological. Monsters.
regnancies Neen

Uterine: 73507 100 80 y 6.
Tubal eee 100 3 96 .50

No. 1.] ORIGIN OF HUMAN MONSTERS. 69

The proper per cent of real monsters was obtained from
the 4 per cent of normal embryos. The 14 per cent of mon-
sters were obtained from the 4 per 100 of normal embryos
in tubal pregnancy, the remaining 96 having become path-
ological at a very early stage. This gives, as is shown in
the table, .56 per cent of monsters for the full 100, which :s
only a coincidence and an improper comparison. Three of
the four embryos that remain, that is, those that produce
normal foetuses, are by no means so according to Von
Winckel.

I have given the data obtained from tubal pregnancy at
some length on account of their bearing upon the etiology
of teratogenesis. No matter how these data are considered,
they all point in one direction—the number of pathological
embryos and monsters is greatly increased in tubal pregnancy.

PARTIAL OR COMPLETE DESTRUCTION OF THE AMNION,
LEAVING THE UMBILICAL VESICLE.

One of the first changes seen in early human embryos is a
destruction of this important organ, the amnion, which de-
velops shortly after the umbilical vesicle is formed. We can
now picture to ourselves pretty well the formation of the
amnion from the epithelium of the chorion if we blend the
observation of Selenka upon Hylobates with the very young
human ovum described by Peters. About the time the ovum
reaches the uterus, when it is less than 3 mm. in diameter,
and after the ccelom begins to form there must be an invagi-
nation of ectodermal cells into the stem of the vesicle within. *
A portion of the cells of this sac gives rise to the ectoderm of
the embryo and the rest becomes the epithelial lining of the
“amnion. *

It is easy to conceive that any change in the environment
which influences the growth of the ovum would first make

70 MALL. [VoL. XIX.

itself felt at the very apex of the growth, and in the early
stages of development this is in the amnion, including also
the ectodermal plate.

At this early stage, probably during the second week of
pregnancy, the three primary layers have established them-
selves well in their capsule of decidua, which must give nour-
ishment to all sides of the ovum through the syncytium and
young villi. In looking through sections of young ova one
cannot help but think that the syncytial cells form the aggres-
sive elements which eat themselves through everything that
comes before them and cause the mucosa of the uterus to
respond at once. Hemorrhages naturally follow such an
action, and, judging by the frequency free blood is found
between the villi, it appears that in all cases the blood comes
in direct contact with the syncytium, which then grows so
much the better. This vigorous layer of cells no doubt nour-
ishes the layer of mesodern below it, which in turn cares for
the embryo, for at this time there is no vascular system to
carry the food from the mother’s blood to the embryonic disc.
The villi which are growing so rapidly must cast some of the
fluid within their mesenchyme into that of the main wall of
the chorion as it splits into two layers to form the ccelom.
Thus, for a time, even after the blood-vessels are formed in
the umbilical vesicle, the nutrition of the embryo passes
through the ccelom exclusively. The first blood-vessels to the
embryo hasten the process from the umbilical vesicle, and it
is not until the heart is formed and the vascular system has
reached the villi that the nutrition passes in through the
umbilical cord. This does not take place until the embryo is
fully 1.5 mm. long, 7 e., in the specimens of Eternod and
Graf Spee. From now on the amnion begins to expand, at
first very slowly and later much more rapidly, and gradually
obliterates the exoccelom. This is complete by the time the
ovum is 45 mm. in diameter and the embryo is 20 mm. long.

About the time the blood-vessels are formed and reach the
embryo an interference in the nutrition of the embryonic mass
naturally results in the destruction of the anlage of the

No: 1] ORIGIN OF HUMAN MONSTERS. 71

amnion and embryo, leaving only the umbilical vesicle, which
may be found either attached to the chorion or lying free in
the ccelom.

During this period, while the ccelom is relatively very large,
a disturbance in the transmission of nutritive substances from
the decidua to the embryo is marked by an increase in the
reticular magma of the celom. This delicate reticulum was
first described about a century ago and is pretty well marked
in normal ova. As the amnion expands to fill the ccelom the
magma reticulé is gradually pushed before it and often
remains for a time as a delicate layer between the amnion
and chorion. When the embryo and amnion are more or
less destroyed the magma reticulé gradually becomes denser
and denser, encircles the umbilical vesicle and fills the ccelom.
In case the amnion is still intact but does not fill the cavity
of the chorion entirely, pathological ova are usually marked
by a mass of dense magma in the exoccelom. This change in
the structure of the magma is so well pronounced in early
pathological ova that specimens which are believed to be
normal on account of a perfect villous covering are at once
recognized as being diseased as soon as they are opened.

The nature of the magma is not known. I have made
numerous tests with Weigert’s fibrin stain, but in no case did
the fibers take on the color. Neither do they appear to be
related to ordinary reticulated tissue, which is present in the
embryonic state in the mesoderm of the chorion, for they are
not connected in any way with the protoplasm of these cells.

As the magma reticulé becomes more pronounced in path-
- ological specimens it is often converted into, or is intermixed
with, a granular substance which may be termed the granular
magma. In case the ovum grows to be large, as is speci-
men No. 115, the reticular magma is often destroyed, leav-
ing only the granular substance, more or less mixed with
fluid to fill the ccelom. In older specimens we often see the
cavity of the amnion filled with a mass of granular magma,
while the surrounding ccelom is filled with reticular magma.
However, stained sections show this separation only in a

72 MALL. [Vor. XIX.

general way, for there is always more or less mingling of
these two substances.

TABEB I:
NorMAL EMBRYOS OF THE FirST AND SECOND WEEKS.

Specimen. Embryo. Ovum. : &
o
| =
mm mm. days
Retersiy of: svanas tenth ya .19 A (5) SS (0) 25 £8) 30
Mertiens ace te Zee 21
BreuSsiscfare space teats 5 38
Reichert... nate essen: Sas 5B 42
Siegenbeck van Heu-
elo nasi, onto 325 CRG AAS

Grail Speen. cee eistan 39 5.568 5 wks.
Nopee arseisrstse sey ee 8 Tou y 7 41
Keeipel sas a un ee eis Ty iSay O3s Gey) 2s ©
EU CeRMOd tae alee toe. it 8) 10.8 x 8.2 x6 34
Grat SPs imac a: 1.54 DO Xi8.5.500.5 5 wks,
INO ieee otoueia ve ahtastol TOK QOX5 40
INOS23 Gras eeryee neice IoXIOXI0 41
NO a2 5 Oricon ao life caters Zi, 10ox9x8
INiOm 3 Sal ota mre. ters 2. Too 1s ro 49
NOP ZO1s meme ns 2. 16X14 X12 42

*References are given in my article in the Johns Hopkins Hospital
Reports, Vol. IX, 1900.

With this introduction to the primary changes in very
young pathological ova we are ready to discuss those cases in
which the amnion and embryo are destroyed, individually and
in groups. In order to make this easier I have brought the
specimens together in Table II, giving certain important data.
Table I includes all of the normal ova I have been able to
collect from the literature and is to be used for making com-
parisons. By comparing the two tables it is noticed at once
that the pathological ova are older and larger than the normal
ones. But, judging by the changes within, it is highly prob-
able that these began some time before the second week of
pregnancy. If their ages are estimated by the size of the
umbilical vesicles they would range themselves from one to

No. 1.] ORIGIN OF HUMAN MONSTERS. 73

TABLE UW:
VESICULAR FoRMS OF PATHOLOGICAL Ova.

No. | Ovum. Vesicle. rae | Amnion. Chorion.
| |
mm. | mm. | days |
1) 8x7 | 1.4x6 Formed |/Fibrous and partly covered
with villi.
304] 15K 7x6 2 of ‘Chorion normal, but decidua
| infiltrated with leucocytes.
158 Haao~ - | 2 . ‘Atrophic. Tubal pregnancy.
143 | 25xIOo + \Normal.
vibe (aie oe iy er Toye | At Partial |Covered partly with villi.
396 7 DXaT: 50 2 Somewhat fibrous and invaded
by syncytium.
134 Re xeTy —| 3X0 33 7 Normal. Embryo infected
| with mother’s blood.
58|20xX 18 X12] 6 71 . .,./Pibrous:
87| 24x 16x9 Dol 42 a8 Normal.
2A eon x TOM Sala 2.0 Multiple Syncytium increased.
78 | 36 X 33 X13 TOs nO 7 a ‘Atrophic.
247|40X 40X17 Pes 2 Nearly normal.
Gat || eS ©) 2 | yalpsias None |Some magma reticulé in coe-
lom.
130] 15 X10X6| 4x3x1.5| 14 a ‘Normal. See Table IV.
12)3 17X14 2X1.5 2H i. Imbedded in pus.
TSOL2OR 15 x TO} 8E-5 37 ai ‘Fibrous. In a mucoid mass
rich in leucocytes.
264|25X 20X15 2.5 58 * Fibrous. Few villi with pus.
14 30 Tos - Thin and fibrous. No villi.
147 | 30x 27 © 20) of 89 * ‘Very fibrous. Few villi.

six weeks, during which time the vesicles grow from one to
six millimeters in diameter. However, if we consider each
millimeter in diameter as indicating a week in age, we again
get into trouble when this is compared with an arrangement
according to their ages as determined by their last menstrual
periods. It seems to be safer to assume that the pathological
changes in these specimens began during the first and second
weeks of pregnancy, and that the chorion continued to grow
while the vesicles within became larger in some cases and
smaller in others. Had the changes in them begun as late as
the third week, when the amnion is sufficiently developed to
remain and continue to grow, entirely different specimens
would have been obtained, as will be shown later on.*

1The age of the embryos is given according to His. Since writing
the above I have come to the conclusion that he has underestimated

74 MALL. [Vou. XIX.

Amnion formed.—One of the earliest specimens of vesic-
ular forms in which the amnion is present but the embryo is
pretty well destroyed is No. 13. There is much magma
reticulé in the ccelom. It is quite clear that the double vesicle
represents the amnion and umbilical vesicle, which are bound
together by a mass of mesoderm. This contains two blood-
vessels, which unite at the point where the mesoderm passes
over into the chorion. There are no other structures of the
embryo present. The tissues have become dissociated, the
mesoderm cells are round, and other round cells are in the
cavity of the yolk sac. In general, we have the remnants of
an embryo a little younger than Eternod’s with the blood-
vessels reaching to the chorion.

An excellent specimen, No. 304, which was cut into serial
sections with the entire chorion and decidua, is most instruc-
tive. The villi of the chorion are normal in shape and are
covered with a very active syncytium. They contain remnants
of blood-vessels within them, showing that at one time there
was vascular connection between the yolk sac and the villi.
The decidua is encircled and infiltrated with leucocytes and
between the villi there is a mucoid mass rich in leucocytes,
showing that the inflammatory process has reached the ovum.
The ccelom is well filled with magma reticulé, in which there
is imbedded the umbilical vesicle attached to the remnants of
the embryo. This is partly covered with the amnion, which
runs out into a stem, containing an allantois, the latter not
connecting with the chorion. There are remnants of a
nervous system and numerous blood islands in the yolk sac,
but no heart.

This specimen corresponds well with No. 13 and gives, in

them, by about ten days for embryos less than 22 mm. long. For
embryos from 22 to 33 mm. long I believe his estimations fairly accu-
rate. To make the proper correction it would be necessary to recast
all of my tables and much of the text. The reader may make them
by adding ten days to the age of embryos less than 43 days old. My
new data, about 1,000 in number, relating to the age of human embryos
will be published in Keibel-Mall’s Handbuch der Entwicklungsgeschichte
early in 1909.

No. 1.] ORIGIN OF HUMAN MONSTERS. 75

addition, the changes in the decidua which caused the diffi-
culty. The equilibrium between the chorion and embryo was
overthrown at about the same time as in No. 13 and the
magma became more pronounced than normal. The tissues
then became dissociated, and on account of lack of nutrition
they began to disintegrate.

The next specimen (No. 158) which belongs to this group
is of about the same age, judging by the size of the chorion.
It is from a tubal pregnancy and is interesting because there
are no villi upon the chorion. The main wall of the chorion
is somewhat fibrous and there are but few epithelium cells
upon it; these come in direct contact with the lining epithe-
lium of the tube. The nodule within is as a double sac, partly
joined by a clump of cells, which runs out into a long process
containing a blood-vessel (?), but does not join with the
chorion. The whole mass appears necrotic, at least it does
not stain well, and probably represents the amnion and yolk
sac, which come to a sudden end due to the radical changes
in the chorion.

The fourth specimen (No. 143) which may be included
with this group is unique, for within a normal chorion there
is a double vesicle much larger than the umbilical vesicle ever
becomes during development. However, the specimen had
been in alcohol for a long time and the cells are mostly de-
stroyed, due to bad preservation. The two sacs, which do not
communicate with each other, are of the same structure as the
mesoderm of the chorion, to which they are bound by a strong
pedicle.

Amnion partly formed.—The five specimens in this group,
Nos. 11, 396, 134, 58 and 87, are most interesting, and have
caused me much trouble. Four of them were considered in
the first communication and need only be reviewed in this place
in order to make the chain of events complete.

No. 11 was first described as a normal embryo because its
chorion and apparently all of its tissues were normal. The
embryonic mass, however, communicated freely through a
rounded and natural opening with the ccelom. Furthermore, I

76 MALL. [VoL. XIX.

had every reason to believe that the abortion was produced
through mechanical means, a circumstance which I have since
learned does not insure a normal embryo. When I received
the specimen (1893) sketches of it were submitted to Pro-
fessors Minot and Graf Spee, who discussed it quite exten-
sively in their letters to me, and they both felt that more
young specimens would have to be studied before this could
be properly interpreted. Professor His, however, to whom
the sections were shown, was inclined to think the embryo
normal, and as such it was first published. At present it
seems to me that the ovum was normal until the woman
“sprained herself six. days before the abortion.’”’ The sprain
was followed by a flow of blood each day until the abortion
occurred. Thus it happened, it seems to me, that the chorion
grew large and the villi small; certainly they are not as well
developed as in the other young ova given in Table I.
Through some means, possibly mechanical, the amnion be-
came torn and the ectoderm spread itself partly over the
ceelomic side of the yolk sac and belly stalk. The amnion in
Peters’s ovum is very delicate at one point, being composed
of but a layer of ectodermal cells, and in Van Heukelom’s
there appear to be actual openings in the amnion. With these
facts before us, it is not remarkable that a break should occur
at this point occasionally.

Another very valuable specimen is No. 396, which was ob-
tained from a tubal pregnancy. Within the ccelom of the
ovum there is a double sac, one of which is clearly the umbilical
vesicle, and the other may represent the amnion and embryo.
What is especially interesting in this specimen is the relation
of the umbilical vesicle to the chorion. At a number of
points they come in contact, are adherent, and the blood-
vessels from the umbilical vesicle pass directly over into the
chorion, from which they spread into its villi. This specimen
proves that the presence of blood-vessels in the chorion is
not dependent upon the development of the body of the
embryo. They may grow to it in a direct way.

A third specimen (No. 134), much like No. 11, also ob-

No. 1.] ORIGIN OF HUMAN. MONSTERS. 77

tained from a criminal case, is equally remarkable, for we have
here the amnion communicating with the coelom. In this case
the ovum had been punctured by a bougie and the ccelom filled
with mother’s blood. The clot is very recent, for it is composed
largely of well-formed red corpuscles. A portion of it is
composed of many leucocytes, and where they come in contact
with the embryo the leucocytes are in a very imperfect state
of preservation, showing irregularities and fragmentation of
their nuclei. Fragmented leucoyctes are also found through-
out the clot, in the blood-vessels of the embryo, in the chorion
and yolk sac. At points in the villi leucocytic thrombi are
found in the embryo’s blood-vessels, which shows the effect
the tissues of the embryo have upon the leucocytes of the
mother. No bacteria were found in a section stained for
them. On the other hand, the tissues of the embryo are well
preserved, there being no evidence of extensive necrosis. How-
ever, on one side of the yolk sac the cells have desquamated.

The bougie in puncturing the chorion probably also entered
the yolk sac and was followed by its collapse. In the table
its dimensions are given as 9 x 3 mm., which equal about a
spherical vesicle 5 mm. in diameter.

The amnion is also torn open, and within it there are frag-
mented leucocytes. The invagination does not include the
whole embryo, for a portion of the mesoderm covering the
yolk sac contains myotomes. The experiment represented
in this ovum gives us much over. which to reflect.

According to the woman’s statement from whom this speci-
men was obtained, the menstrual period had lapsed five days
before the abortion took place, and her mechanical interference
took place but a few days earlier. It is difficult to understand
this high refinement in the production of abortions, and the
degree of development of the ovum and embryo indicates that
the specimen dates back to the last menstrual period. Possibly
morning sickness, which in such cases may precede the first
lapsed period, induced the woman to pass a bougie into the
uterus after the period had been overdue a couple of days.

78 MALL. [Vou. XIX.

The amnion is partly within and partly upon the stem of
the yolk sac in specimen No. 58. In it the mesoderm of the
chorion, villi, pedicle and sac is fibrous and abnormal in ap-
pearance. It may be that in this case a portion of the amnion
broke out of the stem and the portion that remained devel-
oped into a small vesicle filled with beautiful epithelial cells.
There are some blood islands within the stem of the vesicle.
The ccelom is filled with jelly-like magma and the vesicle has
a granular deposit within it.

The last specimen of the group is No. 87. Here the yolk
sac is imbedded in reticular magma and is not connected with
the chorion. It is covered with a layer of epithelium, which
at one point is invaginated. Below this layer there is a thick
mesoderm, in which there are numerous blood islands. The
chorion is normal. On the opposite side of the ccelom there
is a normal embryo of the third week with its own umbilical
vesicle and cord. In this specimen we have twins, one of
which is normal and the other has undergone this remarkable
change, found beginning in specimen No. It.

Multiple amnions.—The last two embryos discussed may
also be classed under this head, and they therefore represent
intermediate stages between the two groups. By multiple
amnions I mean two or more vesicles which arose from the
original amnion located in the stem of the yolk sac. :

In these three specimens, Nos. 24, 78 and 247, nothing
marked is found in the chorion, excepting that of No. 78, in
which it is atrophic. In this specimen the coelom was found
filled with fluid; in No. 24 it was filled with a moderate
amount of reticular magma, and in No. 247 with granular
magma.

In No. 24 the stem of the vesicle is broad and contains
blood-vessels. The endoderm of the yolk sac is well marked
and from it the allantois arises and branches as it spreads,
thus forming a multiple allantois. Within the stem there are
also a number of sharply-defined vesicles, some of which com-
municate with its epithelial covering. Each vesicle appears

No. 1.] ORIGIN OF HUMAN MONSTERS. 79

to be a small amnion, and this condition may therefore be
designated multiple amnion. The second specimen, No. 78,
is much like the one just described. Again the stem of the
vesicle is encircled by a layer of epithelial cells, and within it
there are a couple of vesicles lined with the same kind of
cells. There are also some blood-vessels within the stem.

In the third specimen (No. 247) of this group the vesicle
is detached from the chorion; it is pear-shaped and is lined
‘with a single layer of epithelial cells. The outer layer is rela-
tively thick, is composed of mesoderm in which are located
numerous large spaces filled with blood; there are no blood-
vessels in the chorion. Within this mesodermal layer there
are a number of sharply-defined vesicles lined by a single
layer of epithelial cells which is unlike that of the main vesicle.
It is natural to conclude that the large vesicle belongs to the
yolk sac and is lined with endoderm, and that the smaller
vesicles form multiple amnions and are lined with ectoderm.

Table II shows that the age of the specimens (from Nos. 11
to 78) increases with the size of the chorion. The same is
true regarding the last group, Nos. 21 to 147, which is also
arranged according to the size of ova.

Complete destruction of the amnion.—In the specimens just
discussed it has been shown quite conclusively, I think, that
radical changes may take place in the amnion and embryo of
very young ova when the chorion is affected. The remaining
seven specimens of this group show still greater changes in
the embryonic mass, i. ¢., both the amnion and embryo are
destroyed entirely, leaving only the umbilical vesicle. That it
should be so, and not the opposite, is quite natural when we
take the order of development into consideration. The embryo
and amnion receive their nutrition in early stages from the |
umbilical vesicle, which in turn draws upon the fluid within
the exoceelom. This in turn is acted upon by the exchange of
fluid with the villi.

In these specimens (Nos. 21 to 147) it is seen that the
changes in the villi are more pronounced than in those in

80 MALL. [VoL. XIX.

which the effect upon the embryonic mass was not so marked
and show to what extent the yolk sac can endure hardship.
The degree of change is expressed pretty well by the size and
age of the ova; in the younger ones (Nos. 21, 130 and 123)
the yolk sacs are simply detached, while in the older ones
(Nos. 264 and 14) they are fibrous and well attached to the
chorion.

The amount of magma within the ccelom tells the same
story. There is some in No. 21, considerable in No. 130,
much in No. 123, hard and hyaline in No. 264, and completely
filled in No. 147. Thus we have in these specimens the
gradual changes in the umbilical vesicle after the amnion and
embryo have been destroyed. No doubt some of the earlier
stages (Nos. 21 to 180) would have reached a stage similar
to No. 147 had the ova not been aborted. Instead, the yolk
sacs would probably have been destroyed entirely to make
chorions without embryos and uterine moles. But few of
them could go on degenerating for eighty-nine days, ending
with an atrophic umbilical vesicle.

The first specimen of this group:is composed of two vesicles
with blood islands in the outer layer of mesoderm. Of course
it is possible that one of these represents the amnion, but I
am of the opinion that it is a dilated allantois on account of
its close resemblance in structure and layers with the main
vesicle. Another free umbilical vesicle is found in No.
130. However, it is uncertain whether or not this was torn
away from the main embryonic mass before or after the
ovum was aborted. No. 123 is from a clear case of complete
separation of the umbilical vesicle from the chorion. The
ovum appeared normal, but more careful observation showed
that it was encircled with pus. Within the ccelom the free
~ umbilical vesicle was found to have a large opening on one
side, showing that its destruction had also begun.

No. 180 is another case of entire destruction of the
embryo, leaving only the umbilical vesicle. The chorion con-
tains villi and blood-vessels. Between them there is a slimy
mass, in which there are many leucocytes and islands of

No. 1.] . ORIGIN OF HUMAN MONSTERS. 81

syncytium. The growth of the syncytium appears to have
been violent, and it encroaches upon the mesoderm of the
chorion, which at points is beginning to be fibrous. Here also
the primary trouble seems to be due to the mucus and pus
which bathe the villi of the chorion; they naturally cause
havoc with the nutrition of the ovum.

The next specimen of this series (No. 264) is a very valu-
able one, for its tissues, from the embryo to the decidua, are
unusually well preserved and the menstrual age is given. The
chorion is fibrous and thickened, and between the villi there
is mucus which is well infiltrated with leucocytes. The coelom
is very small, but 10 mm. in diameter, and is filled with a
mass of hard hyaline magma.

The embryo is represented by a vesicle composed of two
layers, the outer of which is much thickened at its attach-
ment to the chorion. Here it is decidedly mesodermal in
character and contains many large blood-vessels, filled with
blood, which spread into the chorion. In the tissues around
these. blood-vessels there are many round cells which are
similar to, and no doubt have come from, the embryo’s blood.
Many round cells are also scattered through the magma.

A similar remnant of an embryo may be seen in specimen
No. 14. The mesoderm is very fibrous and extends over the
vesicle within. Within the chorion there are groups of epithe-
lial cells which are no doubt derived from the syncytium.
There are a few blood islands at the base of the nodule and
two other spaces lined with spindle-shaped cells. The main
cavity of the nodule is lined with epithelial cells, which no
doubt represents the yolk-sac cavity.

No. 147 is a specimen much like No. 14, giving, however,
its menstrual history, which makes it eighty-nine days old.
The chorion is fibrous and partly covered with villi and the
coelom is filled completely with magma reticulé. Lying in the
magma, but detached from the chorion, there is a small vesicle
one millimeter in diameter. One-half of the vesicle is com-
‘posed of the single inner layer, and on the other there is an
additional thick outer mesodermal layer, in which there are

82 MALL. [VoL. XIX.

numerous blood-vessels filled with blood. ‘There are also
blood-vessels in the chorion in the immediate neighborhood
of the vesicle, showing that the two were connected at an
earlier period in their development.

No doubt this vesicle has gradually degenerated, but has
hved so long because the blood cells are more resistant than
any of the other tissues of the embryo, and, therefore, could
hold the yolk sac intact, more or less. However, it is clear
that of the structures of the embryo the yolk sac is the last to
disintegrate when the chorion is affected.

Ova IN WHICH THE EmMBRYO AND AMNION HAvE BEEN
DESTROYED, INCLUDING CERTAIN MOLES.

Under the previous heading those specimens were discussed
in which most or all of the embryo and amnion had been
destroyed, leaving only the umbilical vesicle. Various stages.
of destruction of the umbilical vesicle were also considered.
Altogether there were 19 specimens which came under this
heading. Now we have a second group of 29 specimens in
which the whole embryo, amnion, belly stalk and yolk sac
are missing, leaving only the main wall of the chorion and
its villi.

In the first group a number of the specimens showed fibrous
changes in the mesoderm of the chorion with more or less
destruction of the villi with other changes, such as leucocytic
infiltration or mechanical injury, indicating that the primary
cause for these changes is located in the environment of the
ovum rather than within it.

In the second group, where the change in the embryo mass
is more radical, greater changes should be found in the
chorion, and, in fact, this is the case, as a glance at Table III
will show. The first eight specimens of the group, from Nos.
298 to 204, inclusive, may be considered together, for in
many. respects they are alike. They belong to the first weeks
of pregnancy.

83

ORIGIN OF HUMAN MONSTERS.

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84 MALL. [Vor. XIX.

No. 298 is from a tubal pregnancy regarding which there
was much doubt until the remains of the ovum were found
in serial sections. ‘The remnants of a very small ovum were
found at the edge of the rupture of the tube. They are com-
posed of fibrous villi partly invaded by leucocytes and sur-
rounded by an irregular mass of syncytium, decidua and blood,
I am inclined to believe that the case might have cured itself
if it had not been treated by the surgeon.

The second specimen (No. 278) is of the greatest signifi-
cance in this discussion, for we have in it the whole ovum with
its surrounding decidua, which appear normal, and changes
within, which show that the embryo has been destroyed. The
specimen was removed by a curette from a woman suffering
with endometritis. Although no inflammatory changes were
seen in the decidua and chorion, the condition of the uterus
may have caused the destruction of the embryo. The ccelom
is found filled with reticular magma, and this is permeated
by a coarse network of mesodermal cells, which are continu-
ous with and no doubt derived from those of the chorion. In
one of the sections, lying free in the middle of the ccelom, there
is a small clump of epithelial cells, about 100 in number,
which may have been derived from the embryo. The chorion
contains no blood-vessels and in general reminds one much
of Peters’ ovum. .

No. 71 has a history similar to No. 278, it being, however,
a natural abortion from a woman suffering from endometritis.
The exterior of the specimen is normal in appearance, and in
sections the structure of the chorion and villi also appears to
be so. Within the ccelom there is some reticular magma and
a small mass, which would not stain, and appears like a mass
of dried blood corpuscles. With this there is another speci-
men (No. 204), without any history. Its chorion is again
normal, both macroscopically and microscopically, is filled
with a mass of granular magma, but contains no remnant of
an embryo nor amnion.

The remaining specimens of this group are all from tubal
pregnancies and show no remarkable reactions. They are

No. 1.] ORIGIN OF HUMAN MONSTERS. 85

valuable because they show the early changes in the chorion
when its implantation is faulty. The structure of the main
wall of the chorion and its villi is also more or less changed,
as the table and histories of the specimens show. It is natural
to read into these specimens the following history: The em-
bryonic mass grew for some time, but was soon arrested
because the chorion could not supply the proper nutrition.
Soon the embryonic mass began to degenerate, and this
process was only hastened by the secondary changes which
were beginning in the villi, Soon the whole ovum was dis-
organized, as we see by the study of the specimens.

This group of specimens throws much light upon the pri-
mary cause in the destruction of very young embryos. In
five it is mechanical and in two it is clearly due to endome-
tritis, although no secondary changes are found in the chorion.
I have every reason to think that this kind of abortion is
much more common than is believed to be, for physicians
often have told me that they “found but lost, or threw away,
suspicious specimens,” or that they “sought but failed to find
small fcetuses in suspected abortions.’’ No doubt curing the
endometritis in such cases would favor future pregnancies, as
is generally believed by gynecologists. At any rate, for our
purpose, these specimens show that impaired nutrition due
to faulty implantation causes destruction of the embryo with-
out making any marked impression upon the chorion.

The first group of this series is no doubt composed of speci-
mens of the second and third week of pregnancy, in which the
whole embryo was destroyed and the ovum aborted before any
change took place in the chorion. The next group includes
ova of the third and fourth week, judging by their size, and
by the presence of blood-vessels in the chorion of some of
them.

The smaller specimens of the second group also show no
macroscopic changes in the chorion, but microscopic exami-
nation tells a different story.. In specimen No. 299 there is
a dense magma reticulé, and the mesoderm of the chorion and
the villi appear to be cedematous. Nos. 395 and 181 tell the

86 MALL. [Vor. XIX.

same story. In 310 the villi are of irregular length, their
structure is hyaline with vacuoles, and they contain remnants
of blood-vessels of the embryo. They are imbedded in a
mass of fibrin and pus.

In No. 20 the only change found is a considerable amount
of granular matter between the villi, and in No. 190 there
are no changes whatever; however, the villi contain blood-
vessels. In specimen No. 255 it is again observed macroscopic-
ally that the villi are atrophic, and sections show that the
mesoderm is fibrous. In between the syncytial masses there
are many leucocytes, which have invaded the villi and the
mesoderm of the main wall of the chorion.

Up to this time the ccelom contains reticular magma in
most cases, but as the specimens grow larger and presumably
older first granular magma is found mixed with the reticular
and finally displaces it altogether. The last four ova of the
group under consideration (Nos. 29, 195, 243 and 358) are
each 30 mm. in diameter, may be fully four weeks old, and are
beginning to take on secondary changes. No 29 is filled with
granular magma, the mesoderm of the chorion and its villi
are fibrous and being invaded by the syncytial cells. The
whole is encapsulated in a layer of mucus, in which there are
numerous leucocytes. No. 195 shows no changes in the
chorion, which, however, contains blood-vessels. Extreme
changes have taken place in No. 243. It is an irregular,
collapsed, pear-shaped chorion, showing the beginning of a
solid mole. Sections of No. 358 show that the villi are matted
together, much blood and syncytium being between them, and
they are encircled by a fibrous syncytium rich in leucocytes.

Up to this time the changes in the chorion are quite equally
distributed over its walls, and a change found on one part of
it is also found on the other. However, the impaired nutri-
tion may influence villi which stand side by side, some becoin-
ing smaller and disappearing while others are becoming hyper-
trophic. In fact, one of the best signs of the abnormality of
an ovum before it is opened is this inequality of its villi.
However, when an ovum is collapsed the story is entirely

No. 1.] ORIGIN OF HUMAN MONSTERS. 87

different. In so doing it makes more room for itself, the
various structures from magma reticulé to decidua become
intermixed, and if there is any further growth it is irregular,
as is shown by numerous specimens. In specimens of this
sort, that is those in which the amnion is destroyed in an
early ovum, the diameter of the ccelom does not exceed 24
mm. in any of my specimens, while if the amnion is retained
and reaches the chorion, obliterating the ccelom, the amniotic
cavity is then often over 75 mm. in diameter. In a measure
this is repeating what takes place in normal development, for
here the ccelom reaches its largest diameter (25 mm.) at the
beginning of the fifth week. So in pathological ova, in which
the amnion is absent, the ovum goes on developing, as in the
normal, until the ccelom has reached its maximum size;
beyond this it cannot continue to grow, for under normal
conditions its further growth is due to the presence of blood-
vessels in the chorion, which carry fluid to the embryo from
which the liquor amnii is secreted.

In case the ovum does not collapse, e. g., No. 358, the
walls of the chorion become gradually thicker, the villi longer,
and the diameter of the ccelom smaller. This is seen to be the
case in regular order in specimens Nos. 55, 280, 70 and 223.

No. 55, an ordinary fleshy mole, contains a sharply defined
cavity, which proves to be the ccelom, for it is not lined by
the amnion. From its lining membrane, the chorion, the
villi rise and radiate through a mass of syncytium, decidua,
blood, fibrin and pus. The bulk of the syncytium is necrotic
and the mesoderm of the chorion is invaded in part by leu-
cocytes.

Another specimen (No. 185), as large as No. 55, is con-
sidered here, for it was not the outside, but the inside, of the
chorion that was filled with pus. No doubt the ovum was
punctured by mechanical means and filled with pus, as was the
early stage (No. 134) described above. In this the leucocytes
invaded the chorion from the inside, but had not entered the
villi. Some of the villi are atrophic and some are oedematous;
the syncytium is normal.

88 MALL. [Vot. XIX.

Nos. 280 and 223 follow in regular order No. 55. In the
first the coelom is small, contains some reticular magma and
the wall of the chorion is thin. The villi are not very large,
are well developed, contain remnants of blood-vessels and are
covered with a mass of necrotic syncytium. The whole spect-
men is surrounded with mucus, blood and pus. Leucocytes
have entered the mesoderm of many of the villi. The second
specimen is a solid mass with its base broken off. Radiating
from its base of attachment there are long villi, which en-
circle mostly, and partly penetrate, the main mass of the
tissues composed of blood and fibrin. Between the villi there
is an active syncytium more or less necrotic, which gives the
picture of a cancer. The whole is covered with a capsule of
pus.

The remaining specimens may be considered in two groups,
solid moles and hydatiform moles. Belonging to the first
group (No. 153) is a pear-shaped body composed of an
inverted chorion imbedded in an organized blood clot, inter-
mixed with villi and syncytium. There are also numerous
leucocytes, which have invaded the mesoderm from its ccelom
side. No. 290 is composed of decidua, mucous membrane of
the uterus, blood, fibrin, pus and villi which are being destroyed
by leucocytes. No. 233 is composed of an irregular mixture
of villi, syncytium, decidua, blood and pus. Fresh blood is
in the middle of the tissues, which, like most moles of this
kind, are nourished through their centers. Its exterior is cov-
ered with pus.

To what extent a collapsed ovum may grow is shown in
specimen No. 82. A large solid mass the size of a duck’s
egg was expelled nine months after the last menstrual period.
On the end which lay in the os uteri there is an extensive
ulceration of the mole; otherwise it is very compact. After
it had been hardened, I cut it into two parts, which, to my
astonishment, contained within a collapsed chorion, sending
its folds in all directions throughout the mole. In the mid-
dle of the specimen there are large spaces along the col-
lapsed chorion, filled with fresh blood. The opposite walls

No. 1.] ORIGIN OF HUMAN MONSTERS. 89

of the chorion are in apposition throughout most of the spect-
men, and at points they. have grown together. There is no
amnion, and on this account I place the beginning of this mole
back to the first month of pregnancy. The extensive ramifica-
tion of the folds of the chorion shows that it must have con-
tinued to grow throughout the nine months of its existence,
this being made possible by the nourishment brought to it
by the fresh blood in its interior. Islands of syncytial cells
are located upon the chorionic wall throughout the specimen.
The syncytium shows active growth and its cells stain well
at numerous points where they come in contact with fresh
blood. All the syncytial masses, distant from the fresh blood,
are necrotic, which is undoubtedly due to the lack of nutrition.
Nests of leucocytes with fragmented nuclei are scattered
throughout the specimen. The walls of the chorion are not
invaded by the syncytium.

In a number of the specimens enumerated above it was
noted that the villi are oedematous and hyaline, a condition
which might easily end in hydatid degeneration of the villi,
forming hydatiform mole. In a specimen which contains an
embryo 17 mm. long (No. 357) many of the villi are quite
large and have undergone hydatiform degeneration. Another
specimen (No. 70) contains a small ccelom which sends radi-
ating cavities into the walls of the hypertrophied villi. There
is no amnion. Ina second very large mole (No. 323) most
of the villi are about 5 mm. in diameter, and some of thetn
four times as long. They are very irregular in form, the
larger ones containing cavities, some measuring I5 x 10 mm.,
giving all the characteristics of the ccelom. Between the villi
there are numerous masses of necrotic syncytium, some blood
and leucocytes, which invade the mesoderm of some of them.

90 MALL. [Vor. XIX.

PATHOLOGICAL Ova AND Moises CoNTAINING AN AMNION
Witnh THE Empryo DESTROYED WHOLLY OR IN
GREAT PART.

Under the last headings specimens were described in which
most or all of the embryonic mass was destroyed, leaving the
chorion to outline the ccelom. Such specimens are numerous
and no doubt give rise to most of the solid moles. All other
specimens in which the embryo is destroyed are of necessity
those in which the amnion is formed, sweeps through and
obliterates the coelom in its development and lines the chorion.
It is evident when these two groups of specimens are consid-
ered that the first must arise from ova of the first month, for
in them the amnion is small, and the second group, from older
ova after the amnion has reached the chorion.

In general, the older the embryo is when it begins to become
pathological the more resistant it is, and it follows that the
younger the specimen the more easily it is destroyed. Prob-
ably this is the reason why an ovum without an embryo rarely
contains an amnion. No matter how large the specimen may
be, if the interior of the chorion is not lined by the amnion it
is safe to say that the pathological changes in it began during
the first month (probably during the first fortnight) of preg-
nancy. In case the disease of the ovum, which is usually due
to endometritis, begins during the second month of pregnancy
or later, the amnion is well formed, usually continues to de-
velop, and reaches the chorion. Ova of this sort, which con-
stitute the major portion of my specimens, contain embryos
more or less degenerated, and at best form vesicular moles
with the remnants of embryos within them. In a few of
them, however, the embryos are destroyed, leaving only the
umbilical cords, and in two or three specimens they were also
destroyed, leaving only the chorion and the amnion.

In all of these ova the cavity of the amnion is retained, and
they do not appear to develop into solid moles, but may con-

tinue to grow on indefinitely like those of the group given in
Table ITT.

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ORIGIN OF HUMAN MONSTERS.

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92 MALL. [Vor. XIX.

I shall first consider those ova in which the embryo, or
embryo and cord, has been destroyed, leaving only the
amnion, and will leave the ova or moles with pathological
embryos to follow. There are many of them, and when they
are classified in weeks they tell a continuous story.

Table IV gives the list of ova in which the amnion is
retained, with such other data as I have been able to collect.
Unfortunately, the data relating to the age of the specimens
are very incomplete. However, it is possible to connect the
specimens in a satisfactory way if we begin with those which
have remnants of the embryo attached to the cord, and
gradually proceed to those in which the cord is destroyed
entirely, leaving only the amnion and the chorion.

In general, the size of the chorion and cord do not corre-
spond properly with each other, showing that either one or
the other has been retarded in its growth. In specimens Nos.
130 and 32, for instance, the embryo masses are of about the
same size, representing cords of the second month, but one is
from a small and young ovum and the other is from a large
and much older one. It is fair to assume that the embryo in
No. 32 was destroyed when the ovum was as small as No.
130 is at present.

Table IV gives a list of the specimens with all stages of
destruction of the embryo after the amnion is well formed,
leaving only a portion of the embryo, or, in extreme cases,
the umbilical cord alone. In a few of the specitmens the cord
is also destroyed and in them the chorion is lined simply by
the amnion. The villi of the smaller ova of this group appear
quite normal, and for this reason I have been inclined to
think that in them the primary cause lay in the embryo
itself, and that in the older stages the changes found in the
chorion were of a secondary nature. Further investigation,
however, may reveal the same early changes in the neigh-
borhood of the villi here as are found in the specimens
in which the embryo and amnion were destroyed during
the first four weeks of pregnancy (Table III). Here also the
earlier specimens, those with numbers lower than 150, did

No. 1.] ORIGIN OF HUMAN MONSTERS. 93

not show any signs of endometritis, but since then nearly all
of the specimens collected have been hardened in formalin in-
stead of being first washed in water or in weak alcohol, as
uninstructed physicians do so frequently. Further observa-
tion with well preserved specimens will also probably show
signs of endometritis in specimens of this group, less than
30 mm. in diameter.

The embryo is entirely destroyed, leaving only the amnion
in a very small per cent of pathological ova. Usually the
embryo continues to grow slowly in an irregular fashion, but
sometimes there is a destruction of some of its parts. In
most of these cases, however, the circulation has been estab-
lished and the ccelom is pretty well obliterated, thus elimi-
nating the importance of the magma reticulé. Therefore
primary changes in the embryo are clearly associated with
the blood and the vascular system, and this naturally affects
the embryo more than it does the other structures.

I shall consider No. 37 first, because it still contains the
outline of a portion of the embryo. The atrophic head of
the embryo is seated upon a very small cord and these are
surrounded by the amnion. The umbilical vesicle is attached
to the side of the cord, but does not reach into the embryo.

The central nervous system is very rudimentary, and the
heart, liver, myotomes and lower end of the body are wanting.
The lower jaw is still recognizable, and from it two arteries
pass over into the cord. The single vein of the cord ends
blindly just below the rudimentary branchial arch. The size
and degree of development of the embryo places it in the
beginning of the third week, when no doubt its destruction
began. The chorion, however, belongs with those of the
fourth or fifth week, which indicates that the process of
atrophy has been under way for a week or two.

In specimen No. 130 the embryo is reduced to a small
mass of round cells showing no structure whatever. The
umbilical cord is filled with its usual blood-vessels, showing
that an embryo had been present at an earlier date. The
whole is inclosed in a relatively small amnion, which no

94 MALL. [Vou. XIX.

doubt protected and held together what little of the embryo
there was left. The cord extends to the chorion in the wall
of the amnion, showing why the yolk sac, described on page
80, broke away so early. The amnion fills only half of the
coelom, the remaining portion being stuffed with a dense mass
of magma reticulé.

No. 257 is similar to No. 130, inasmuch as both of them
have small bodies upon the end of the cord, representing the
remnants of the embryo. However, it is much older, the
chorion being larger and many of the villi having under-
gone fibrous changes are atrophic. The body at the end of
the cord is not the remnant of the embryo, but simply its
continuation, with the umbilical vein running through it.
Although this specimen might have passed for a normal one -
when examined superficially, more careful examination
showed that the decidua was infiltrated with leucocytes. The
chorion is lined by the amnion, which is mostly adherent and
contained a clear fluid. No remains of a disintegrated em-
bryo were found within the amnion.

Another specimen with a small remnant of the embryo is
No. 342, which is from a tubal pregnancy. Attached to the
free end of the cord is a bit of tissue which must belong to
the embryo, with a small mound of active cells growing in
it. The chorion, amnion and ‘cord have undergone fibrous
degeneration.

Nos. 25, 32 and 198 are specimens of simple ova with a
naked cord projecting into the amniotic cavity in each case.
In No. 198 the amnion is filled with reticular and granular
magma intermingled with scattered flakes of the embryo and
numerous free cells. The cord is rounded at its free end and
its blood-vessels are empty. The mesoderm of the chorion,
villi and cord is fibrous, with an excess of spindle-shaped cells
scattered through it. Similar stages are shown in specimens
Nos. 32 and 25. In both of them the blood-vessels are well
filled with blood, and in the first there is an extensive wander-
ing of blood cells into the surrounding tissue, especially at the
tip end of the cord. Here they stain intensely with carmine

No. 1.] ORIGIN OF HUMAN MONSTERS. 95

and suggest very much a section through an ulcerating
wound. No. 25 may possibly represent a more advanced
stage, inasmuch as the free end of the cord is more rounded.

To what extent a cord may grow, or at least round itself
off, is shown in No. 279.. The fleshy chorion is composed
of villi which seem to be nearly normal, the mesoderm being
somewhat hyaline in structure, with a diminished number of
nuclei scattered through it. Within there is a large free
umbilical cord curled upon itself and rounded at its free end.
No doubt the fcetus escaped from its membranes before they
were expelled. However, I was unable to determine whether
this had really taken place. The blood-vessels of the large
villi are well developed, indicating that at one time the foetus
present must have been pretty large. At any rate, the broken
end of the cord became rounded and healed over after the
foetus had been broken off.

Specimen No. 77 shows that the free cords are gradually
destroyed if the ovum is retained in the uterus long enough.
In it the chorion and amnion are both more fibrous than
normal. The villi are being invaded by leucocytes and syn-
cytium, giving the secondary changes which are often seen
when the mesoderm of the villi has lost its vitality. No rem-
nants of blood-vessels are present in the villi. The cavity of
the amnion contains a clear fluid, and on one side there is a
small stumpy cord, about one millimeter in diameter, which
attaches the amnion to the chorion.

Nos. 334 and 379 may also be considered with this group.
No. 334 formed a fleshy mole, with a cavity in its center,
15 mm. in diameter, and contains the fragment of an embryo
which must have been fully five weeks old when it died. The
main tissue of the mole is composed of uterine mucous mem-
brane, decidua, blood and pus, with a ramifying chorion in
it. The wall of the chorion is infiltrated with leucocytes on
its outside and invaded by syncytium from its inside. Had
it not been for the fragment of an embryo this specimen
would have been grouped in Table III. No. 379 contains a
granular embryo, 10 mm. long, which readily fell into pieces
upon being handled.

96 MALL. [VoL. XIX.

Nos. 77 and 334 show what may become of the chorion and
amnion when they are retained in the uterus long enough.
The villi are attacked on the outside by leucocytes and syn-
cytium, the cavity of the amnion collapses, or is penetrated
and filled, making the mole solid,.as is the case in so many
younger ova after the embryo and amnion have been de-
stroyed.

Another specimen belonging to this group is No. 93. It
came to the laboratory fresh, enveloped in its decidua, and
the whole was hardened in formalin. Between the decidua
and the ovum there is a layer of blood and fibrin. The main
body of the mole is composed of irregular hypertrophied villi
with a great amount of blood and syncytium between them.
Occasionally the syncytial cells are found in the mesoderm of
the main walls of the chorion. The small cavity within is
lined with the amnion and is filled with blood. No embryo
was found. Nos. 159 and 369 are similar specimens, since
in them the cord is also destroyed entirely. No. 159 is com-
posed of fragments of a mole, the embryo having been lost.
However, the fragments are made up of mucous membran2
of the uterus, large portions of the chorion and some frag-
ments of the amnion. The mucous membrane is full of small
abscesses, and leucocytes have invaded the mesoderm of the
chorion and its villi. The syncytium is very active and at
numerous points it also has invaded the mesoderm of the
chorion and villi. The amnion is hyaline, thickened, curled
upon itself, and at points its epithelial layer has proliferated.
forming small mounds.

The specimens just described show the fate e, ova after
the embryo is destroyed, leaving first the cord and amnion
and then the amnion alone. Finally the cavity of the amnion
is punctured, the ovum collapses and the whole is converted
into a solid mole. Specimens of this kind are rare, since most
solid. moles are formed from ova in which the amnion and
embryos were destroyed at a much earlier date.

No. 1.] ORIGIN OF HUMAN MONSTERS. 97
PATHOLOGICAL EMBRYOS OF THE SECOND WEEK.

The preceding pages have been devoted to the discussion
of those pathological ova in which the embryos were nearly
or entirely destroyed, leaving only the membranes. A large
number of these specimens appeared to be normal ova when
examined superficially, but careful examination showed that
in many of them mucus, leucocytes and pus were present be-
tween the villi. In many the chorion was thickened and more
or less invaded by leucocytes and syncytium, while in others
the cavity within had been obliterated completely to form
typical fleshy moles. We have in them all stages of trans-
formation between young normal ova and solid moles.

The specimens in the preceding sections are easily divided
into two groups: the first, in which the embryo and the
amnion are destroyed, and the second, in which the embryo
is destroyed but the amnion and more or less of the cord
remains. In each of these groups there are intermediate
stages which may be properly considered under this heading.
In the first group these changes began in very early speci-
mens, and in some of them the destruction of the embryo and
amnion was not always complete. These might properly be
considered with the embryos given in Table V, but I have
found it more convenient not to do so and have included in
this and subsequent tables only those embryos in which the
form and structure could be made out with considerable cer-
tainty. By doing this there is still a wide margin left for the
imagination in linking the pathological specimens of a given
week with normal embryos. After this has been done it is
easier to correct errors than it is when the specimens in which
the embryos have been destroyed are grouped with atrophic
ones. My arrangement for the present is as follows:

(1) Normal embryos.

(2) Atrophic embryos.

(3) Remnants of atrophic embryos.

(4) Ova with amnion but without embryos.
(5) Ova with neither amnion nor embryos.

(6) Moles.

98 MALL. [Vor. XIX.

What has been said about ova with neither embryos nor
amnion applies equally well to those in which the amnion is
not destroyed. In this group there are also all intermediate
stages present, and they can be arranged in a series, if con-
sidered alone, for if the embryo is present there is also an
amnion, and adding them spoils the group. The group given
in Table IV could, therefore, be scattered under the follow-
ing headings, but this is not convenient, because the absence
of the embryo makes it difficult to determine at what time the
pathological changes in the embryo began, and, furthermore,
it is easier to consider alone those specimens in which the
amnion is present with more or less of the cord, including aa
occasional fragment of the embryo. This group blended with
embryos over four weeks old would compel us to subdivide
those of each week as follows:

(1) Normal embryos.

(2) Atrophic embryos.

(3) Remnants of atrophic embryos attached to the um-
bilical cord.

(4) Umbilical cords alone.

(5) Ova lined with an amnion alone.

(6) Moles with remnants of the amnion present.

With this brief introduction, I shall proceed to consider
pathological ova in which the development of the embryo is
arrested, beginning with those of the second week. In my
first Contribution there were none belonging to this list; in
the second Contribution there was one. I now have three
new ones (including No. 12) to add.

TABLE, WV:
ARRESTED DEVELOPMENT OF THE Emsryo. (Second Week.)

No. | Embryo. | Chorion. oe ont Changes in the Chorion.
mm, mm. days

162 x 70% 30 X 30 81 Atrophy.

250 op IoXQ9xX9Q Leucocytic infiltration of

decidua, chorion normal.
321 oN 40 X 40 X 20
12 2.1 20 X 20 41 Small amount of mucoid mass
Nor- between villi.
mal(?)

No. 1] ORIGIN OF HUMAN MONSTERS. 99

The embryo of specimen No. 162 is one millimeter long,
with structures which would make it as old as Eternod’s or
Graf Spee’s, given in Table I. The chorion is very thin,
devoid of villi and enveloped in layers of coagulated blood.
Through this but little nutrition could have come to the em-
bryo, if it got any at all. The amnion fills the entire chorion
and its cavity measures 35 x 12 x 12 mm., although the
whole specimen measures 70 x 30 x 30 mm. According to
the menstrual history the age of the specimen is at least
fifty-three days, and if we deduct thirteen days, the age of
the embryo when it first became affected, then the pathological
process must have continued during forty days. Sections of
the embryo show that we are dealing with a remarkable speci-
men, in which great changes have taken place gradually. All
of the organs and tissues are dissociated, that is, they have
grown in an irregular manner, each one growing by itself,
not being markedly influenced by the surrounding structures.
The different tissues are not of uniform structure, being
mucoid in some places and necrotic in others, as is shown in
the figure. The mucoid tissue runs as a column from the
heart to the apex of the nodule and may have been derived
from the chorda dorsalis. At the point of union between the
amnion and chorion there are three elevations from the em-
bryo mass into the celom. These are marked in the figure.
The heart lies within a pocket of its own, which communi-
cates with the exoccelom and is filled with blood. ‘There are
also blood-vessels filled with blood in the center of the embryo.

This interesting specimen of a dissociated embryo, that is,
one in which the tissues grew in an irregular fashion, is ac-
companied with another excellent one, No. 250, in which
these changes are just beginning. In many respects it is
normal, and for this reason I have also included 1t in Table I
as an embryo of the fourteenth day. The ovum and decidua
were curetted from the uterus and came to me opened and
well preserved. The presence of an excess of magma reticulé
gave the hint that the specimen was not quite normal.

The chorion, villi, syncytium and decidua are beautifully
developed and are normal in structure. Between the villi

7

100 MALL. [Vov. XIX.

there is much mother’s blood and within them there is a well-
developed system of capillaries filled with embryo’s blood.
There are numerous leucocytes in the decidua, but they do
not form abscesses.

The front end of the amnion is wanting and its free ends
are well imbedded in reticular magma, showing that this
injury took place before the abortion was produced. The
embryo is normal in form, the heart and blood-vessels well
developed and filled with blood. The rest of the organs are
about of the same stage at No. 391, an embryo of the four-
teenth day. The tissues of the embryo and the ventricle of
the fore-brain are filled with numerous small round cells with
fragmented nuclei. Most of the blood corpuscles are still
within the blood-vessels, but those within the tissues are per-
fectly normal and in no way do they seem to give rise to the
strange cells in the tissues. However, it may be noted that
the mesodermal cells are diminished in number in those tis-
sues in which the round cells are present, which indicates that
the one changes into the other. The primary histological
change in this embryo is found in the mesoderm, which is
dissociating to form some of the so-called wandering cells.
Later this process affects the wall of the vascular system and
the blood cells escape into the tissues, as was pointed out by
His. The cells within the ventricle of the brain as well as
those of the neural tube are mostly fragmented and have be-
tween them a few normal blood corpuscles. It is probable
that most of these new cells arise from the dissociated nervous
tissue. J shall come back to this question from time to time
as I discuss specimens which have changes within them that
bear upon this point. However, this much is clear: the round
cells with fragmented nuclei lying within the tissues have not
emigrated from the blood, but, instead, have arisen by a pro-
cess of dissociation of the tissues within which they lie.

The process of dissociation, begun in No. 250, is carried to
an extreme degree in No. 321. Both of the embryos are of
the same size, but in the second the amnion and chorion have
continued to grow. The chorion is normal in appearance and

No. 1.] ORIGIN OF HUMAN MONSTERS. IOI

is lined entirely by the amnion, the cavity of which is 35 mm.
in diameter. It is interesting to note that this ovum has
reached its maximum growth without the presence of a vigor-
ous embryo. Ova without embryos rarely exceed 40 mm. in
diameter, and in normal development the amnion reaches the
chorion and obliterates the exoccelom in ova of this size. If
the cavity of the amnion is to exceed 40 mm. in diameter, it
is necessary to have a fairly active embryo within it to secrete
the liquor amnii. As long as there is an exoccelom present,
which is not obstructed by magma reticulé, it appears as if
fluid of the amnion is obtained from that of the ccelom.

In this specimen (No. 321) the embryo is attached to the
chorion at its middle, that is, there is no umbilical cord left.
The body cavity of the embryo spreads out on the inside of
the chorion, and into this the degenerated heart hangs. The
dissociation of the tissues is pretty complete, as in No. 162.
The outline of the brain is barely recognizable and all the
tissue in the tail of the embryo is of equal density. Here the
dissociation is complete. Unfortunately, the specimen had
been preserved in 50 per cent alcohol for ten days before it
was sent to me, and in a measure the extreme degree of dis-
sociation may be due, in part at least, to the macerative influ-
ence of the weak alcohol. However, this could not alter the
general outline of the embryo and its organs.

No. 12 is extremely interesting, for it also is probably
pathological, although I have often referred to it as being
normal. When it came to me I found considerable magma
in the coelom, enough to almost obscure the embryo, but on
account of the general normal structure of the tissues I over-
looked the excess of magma. More careful investigation of
the chorion shows that there are also some fibrinous or mucoid
masses between the villi. They also indicate that the speci-
men is not quite normal. Furthermore, there is a marked
anencephaly and probably the beginning of spina bifida pres-
ent. Before a definite opinion can be given regarding the
normality of this specimen it will be necessary to examine
with much greater care than has been done the tissues of the

102 MALL. [Vov. XTX.

embryo, and especially those of the chorion of many so-called
“normal” specimens. This will be done, no doubt, in the
near future.

EMBRYOS OF THE THIRD WEEK.

The specimens of the third week can be divided into three
groups, representing normal embryos 16, 18 and 20 days old,
respectively. In the first division there is but one specimen,

TABLE VI.
NorMAL EMBRYOS OF THE THIRD WEEK.

| |
| | z,
Specimen. | Embryo. | Chorion. % &
ream
| | |
mm. mm. days
No. 12 oa [5 X, 18 35 4I
Om SOT een 2h Gay) 42
His (E) 2.1 S sixes ss
Eternod 2p te 16.3
His .(L8). sane 2205 Ree nes 40
His (SR) 22 9x8
His (L) 2.4 9x8
homsonmyaee met Bole nS Be ike) 14
INGA SEG cite sums otors 2.5 20% tS Kyte 42
Chiaringt. 22 S220). 2.6 15 x12x8
His (M) . 2.6 Siaa75
Graf Spee 2.69 15 0d, 42
lab} (0018) ogous oc 3 42
No. 239 3 TO X 17 7S 50
Janosik 3 Sat 43
Ipbts, (SYED scanoons Bebe HAUS i0it 48
No. 164. 3.5 iy) Sati Bie 3H)
WMossre Oramecerente ges De ROIS 17
INO. (Sieiesoneis oe 4 24X%16x9 42
iy Cove df lepers an 4 TAs <0 56
Ecker. 4 45
His (III) BOC 4 BO28 OS 51
lal) (WAS) 65 nisc 06 ¢ 4.2 15
Steubenrauch (K) Aue 52
Os TAS) oes Hees 4.3 I7 X14 X10 38
WiASmer aarti Me 20
(Pa AOR re 4.5 30 X 30
Hensen\... 0... 4-5 aI
ING: 9005s 2 paistcee 4.5 22 X% 20
INGM20S).. .2c1. ens 4.5 30X23 X15

No. 1.] ORIGIN OF HUMAN MONSTERS. 103
TABLE VII.
ARRESTED DEVELOPMENT OF THE EMBRYO.
(Third Week.)
No. |Embryo. Chorion. areas Changes in the Chorion.
mm. mm. days
166 2.3 40 X 40 X 40 iB Tubal pregnancy.
II5 2 BOR Exa2 56 | Atrophic.
eeG ies | f§ Atrophic.
9 3 nie: Tubal pregnancy: '

209 3 2a ES KILO | Atrophic.
246 3 BO om Tl Hyaline.
252 3 84 Hyaline.
292a| 3.5 50 X 30 X 30 54 Fibrous. ™
Bi ge 45 X45 X22 Fibrous and atrophic.
400 555 La

189 4 28 X25 X15
228 4 60X25 X25 79 Very fibrous.
244 4 25X15 X15
253 4 Zo 40 505 Hyaline.
302 4 25 2050 16 Fibrous.
309 4 23 X 20 X 20
399 4 4or 5 wks
402 4 40X%25xX20 |6or8wks
328 a.5 Normal and covered with nec-

rotic syncytium.

No. 166, and in it the dissociation of the tissues is complete.
This is not remarkable, for the menstrual history says that
it is 71 days old, showing that the pathological process has
been under way at least a month. The ovum has thick walls
with a large cavity within lined entirely by the amnion, which
is not attached to it at any point. There are no blood-vessels
in the villi of the chorion. The embryo is cylindrical in form
and is attached for half its length to the amnion and then
perforates it. Its organs and tissues are almost completely
dissociated, there being but the faintest outline of the nervous
system in its center. In the tail end of the embryo there is a
blind tube, which may represent the allantois. Within a sac
on one side of the body, which communicates with the ccelom,
there is a small mass representing either the heart or the
umbilical vesicle. Greater changes could not have taken place
without obliterating the anatomy of the specimen entirely.
There are eight specimens (Nos. 115 to 400) of the second
group in this series, that is, embryos which began to degen-

104 MALL. [Wor soles

erate when they were 18 days old. A variety of changes
are found in each specimen which are by no means of the
same degree, thus permitting their discussion in regular order.
It is probable that those with the least amount of change in
them have been under pathological influences for less time
than in those in which the tissue changes are more marked.

There are practically no changes in embryo No. 209, and
for this reason it may be classed with normal specimens.
However, it appears as if the chorion were atrophic, being
very thin immediately over the embryo, and the amount of
magma reticulé within the cclom is greatly increased.
There are some changes in the amnion, as it has become
adherent to the embryo over its tail and back, and is wanting
entirely over its head. There are numerous cells in the sur-
rounding magma which may have migrated from the meso-
derm. It is clear that in this specimen the primary trouble
is in the chorion immediately over the embryo, which receives
most of its blood-vessels at this stage. The amnion and ccelom
were next affected, and had the abortion not followed the
tissues and organs would soon have dissociated.

' The dissociation of the tissues is well under way in embryo

No. 246, the chorion of which is somewhat hyaline and the
amnion greatly distended. Unfortunately, the embryo is
broken. Enough of it remains, however, to show that the
central nervous system is distended and partly filled with
round cells, which seem to be derived from the dissociated
neural tube. The heart and large blood-vessels are empty,
and the liver and optic vesicles are wanting.

The changes in this specimen can be ascribed to the hyaline
chorion, but it is difficult to understand how this can cause dis-
tention of the amnion and destruction of the umbilical cord. At
any rate, the process of dissociation is well illustrated in this
embryo. The sharp boundaries of the tissues and organs are
obliterated and the cells which are liberated take on an indif-
ferent form. With the dissociation of the walls of the blood-
vessels the blood corpuscles wander out, to be added to the
dissociated tissues, and convert the whole into an indifferent

No. 1.] ORIGIN OF HUMAN MONSTERS. 105

mass, which barely outlines the embryo. Such a condition
is found in No. 196. The tissues are nearly homogeneous,
only the central nervous system and some of the large blood-
vessels being recognizable on account of the increased number
of nuclei in these regions.

In No. 115 the amnion is greatly distended and the embryo
is spread out upon it, much as is the case in the chick in
normal development. The body cavities communicate freely
with the ccelom, Wolffian bodies are still visible, and the
central nervous system, heart and some large blood-vessels
are represented as bands of round cells.

Various degrees of dissociation of the organs are seen in
different embryos, as is naturally to be expected. In No.
292a, for instance, the outline of the body cavity is very
marked, it being distended and partly filled with round cells.
The amnion is also greatly distended, filling the entire ccelom.
There is no umbilical cord. Some of the spinal cord is still
sharply outlined; otherwise the dissociation is complete.

In embryo No. 252 the dissociation is complete with the
exception of the eyes, which have been converted into small
black spots composed of pigment cells. The skin is also
markedly thickened, the epidermis forming papillomata, as
well as small lens-like bodies.

In the specimens just considered only those organs which
are present in the early part of the third week were seen,
there being no signs of cartilage, muscles nor peripheral
nerves. In the next group of ten specimens we have clearly
the remains of organs and forms of embryos to correspond
with normal ones of the latter part of the third week, that is,
embryos 4 and 4.5 mm. long.

This group can also be arranged in the order of the degree
of pathological change. In No. 189 the central nervous sys-
tem is open below throughout its whole extent. A number
of motor nerve roots are developed, more in the region of
the tail than elsewhere. There are no cranial nerves present.
The heart is almost detached from the body, and the large
blood-vessels are irregular in shape and changed entirely from

106 MALL. [VoL. XIX.

the normal type. The liver, stomach and intestine are want-
ing entirely, and the dissociation of the optic vesicle, chorda,
allantois is almost complete. In this embryo the branchial
arches and brain show the least changes in them, while the
rest of the tissues have suffered most.

Specimens Nos. 302, 309 and 328 are in many respects
alike and may be considered together. The walls of the brain
and cord are much folded and fill the central cavity in No. 302,
while in the other two they are thin, the central cavity being
enlarged and well filled with round cells, which, however, do
not all seem to arise from the walls of the nerve tube, for
their nuclei are smaller, being similar to those of blood cells.

The tissues of these embryos are pretty well dissociated,
being composed largely of round cells, within which the out-
lines of large blood-vessels may be seen. No. 328 has arms
and legs attached, which have undergone mucoid degenera-
tion, a well marked cavity, pleuro-peritoneal, and finally rem-
nants of precartilages which are not fully dissociated.

In the next embryo (No. 228) the central nervous system
has also shown itself most resistant. It is markedly dilated
and the walls are partly dissociated. There are also small
links of cells present, which remind one very much of the
growing cord, connecting large masses of dissociated tissue.
The ventricle is dilated and has within it a large mass of
dissociated nerve cells. In the face there are two large nerve
tubes extending from the brain, which no doubt represent the
eye vesicles and their stalks. The embryo with epidermis
intact, connects with the degenerated but apparently active
umbilical vesicle, but not with the chorion. The vascular
system is represented by a dissociated heart and a large blood-
vessel, which extends into the umbilical cord. The rest of
the tissue is a dissociated mass, more or less spotted, being
composed of a variety of cells, including possibly remnants
of myotomes. |

Degeneration of the dissociated structures now follows
rapidly. In No. 253 the embryo still shows the outlines of
the pleuro-peritoneal cavity within, but the tissues have be-

No. 1.] ORIGIN OF HUMAN MONSTERS. 107

come more hyaline, the round cells having diminished in
number. Most of the central nervous system is fully de-
stroyed. There are traces left of some of the large blood-
vessels, the Wolffian ducts and the chorda dorsalis. No. 244
may be considered together with this specimen, for in it
radical changes have also taken place. The central nervous
system is still sharply defined, more so in the brain than in
the spinal cord. The heart is represented as a mass of cells
in front of the head. Below this there is an irregular body,
probably the dissociated liver, composed of epithelial-like
cells intermixed with some round cells. The rest of the tis-
sties are of homogeneous structure, with an occasional necrotic
mass. In the tail end of the embryo there are some blood
spaces with blood corpuscles, some of which infiltrate the sur-
rounding tissues. In many respects this specimen resembles
No. 115, with the difference that it is larger and was prob-
ably a little older when the pathological process began in it.

PATHOLOGICAL EMBRYOS OF THE FouRTH WEEK.

No doubt the reader has noticed that the embryos grow
more and more resistant as they become older, and this condi-
tion continues to a more marked degree in those of the
fourth week. In embryos of the second week pathological
changes in the chorion were followed by a partial or com-
plete destruction of the amnion and embryo, while in those
of the third week it is not always the same organ or tissue
which resists the influence longest. However, the brain and
heart are recognizable in most of the specimens.

When we reach the fourth week we find that the main
change in the normal embryo is due to the addition of the
peripheral nervous system, which is associated with a sharper
delineation of the organs; they begin to assume some of their
adult characteristics. A normal type with which to compare
these changes is seen in embryo No. 2, which has become a
standard. In my description of pathological specimens of the
fourth week I shall keep this embryo constantly in mind.

108 MALL. [VoL. XIX.

The specimens of the fourth week cannot be considered in
the sequence given in Table IX, for a number of them are
straightened and, therefore, measure larger than others that
‘are more advanced in development but curled up in their
natural shape. This, I think, is well shown in the various
illustrations. However, it is clear that Nos. 334, 285, 312,
336 and 347 are decidedly larger than the rest, about the
same stage of development as the normal specimen No. 2, and,
therefore, about twenty-eight days old. The rest of the speci-
mens are younger and belong to the beginning of the fourth
week. In the first and younger group some of the embryos
that are straight and measure 8 mm. are a little earlier than
others that are but 5 mm. long.

TABLE VIII
NorMAL EmBryos OF THE FourtH WEEK.
E
Specimen. Embryo. Chorion, 2 &
g <q
Ss
mm. mm. days
INGOs SOs civere niet 5 24x18x8
iSiC)2)) ere 5 20X15
His (W) 5 25 X 20 2I
Rist (IRS) Aare renee che 5 22
WERE 55 ab o400 05 Boe 22 18
No. 19 S55 TOM LA.
NOs TOi syereeretieres 6 24x18
INO}, 2akers ars asioranens 6 40 X 40 ir
NOtP2 4S actu tence 6 58
Steubenrauch (1). 6 45
Ion (Secon oto 2 cexeny ao 54
NOMITTO ses eos 6.5 28 X 20X10 55
INOS 2s fade evens 7 BS xe)5 52
INO wES Ss cease 7 18 x 18
INO:aNS Tirana 7 64
Steubenrauch (11) 7 51
Hist (B)F a, sesnes 7 25 X 22
Eis ei(Sti)ieeese. ve A 2E X17 57
Meyer \it sedis 8 45 28
INGOs 22a a ee 8 40 X 33 X 33
No. 2odi.2 te oF 8 22X11 X11 49

No. 1.] ORIGIN OF HUMAN MONSTERS. 109
TABLE IX.
ARRESTED DEVELOPMENT OF THE EMBRYO,
(Fourth Week.)
a! 1 j 5
No. ae eee | gi tas Changes in Chorion.
mm. mm. days
122 5 20X16x6 65 Atrophic.
136 5 tA SIT xX 6 56 Atrophic.
150 5 36 0 SEO But few villi.
291 5 ? Atrophic.
398 5 : :
334 5 | sox 40x30 | 4wks. | Fibrous. Infiltrated with leu-
cocytes and syncytium.
80 5 24xX18x8 Small amount of mucoid mass
between the villi.
401 5:5
340 6
207 6 3 mo.
104 7 oe nied lane i. pe a al 35 Atrophic.
379 | 4th wk. | 35x 25 X15 | 10 wks. | Fibrous.
60 8
IIO 8 46 X 30 X 30 82 Fibrous. Invaded by leuco-
; cytes.
I4I 8 40 X 30 X 20 78 Fibrous. From same woman
No. 110 was obtained.
275 8 40 X 30x25 | 2mo. | Fibrous.
285 8 4525535 % 35 We Very fibrous. Atrophy.
289 8 4 wks.
ane 8 26 Ges TO Fibrous. Invaded by leuco-
cytes.
347 8 40 X 35 X 30 Fibrous. Infiltrated by leu-
cocytes.
336 8 Bh xa 2hoe 15 Hyaline and fibrous.

Specimen No. 136 contains in it a normal embryo of the
fourth week, but its enveloping chorion is too small for its
age. The villi of the chorion are fibrous, but contain a large
number of blood-vessels which are well distended with blood.
The syncytium is very active and no doubt provided well for
the embryo. The only marked changes in this specimen are
the fibrous chorion and the excessive amount of magma re-
ticulé in the ceelom. Possibly the inequality of things may
have brought about the abortion.

Of the remaining specimens of the first group, No. 312
shows the least amount of change in it. The embryo, how-
ever, is straight, shows three gill arches and some myotomes.
The spinal cord can still be outlined in the tissue of the body,
which is well filled with round cells.

II0 MALE: [Vor. XIX.

Generally, in the rest of the embryos, the brain is solid,
the spinal cord dilated, the blood-vessels more or less dis-
tended with blood and the remaining organs and tissues pretty
well dissociated. These changes are least marked in No. 297,
which, however, is a pretty typical one. The outlines of the
precartilages can still be made out, and some of the peripheral
nerves are present. The lower jaw is disintegrating, which
naturally brings the distended medulla closer to the midventral
line of the head. All these changes are more pronounced in
No. 340. The dissociation of the organs is here quite com-
plete, with some indications of growth of the mesodermal
tissue, including the precartilages. In the spinal cord there
is a tendency toward regeneration, provided the curious
bands of cells seen here indicate it. The dissociation of the
larger blood-vessels is practically complete, but their outlines
can still be seen, although many round cells fill the surround-
ing tissue. This condition is practically completed in the
embryo of specimen No. 275, in which but few of the tissues
are recognizable.

In specimens Nos. 104, 110 and 141 the destruction of the
embryos is pretty well under way, showing what may be the
fate of embryos of this sort. The details are much the same
in the different specimens, and may be summed up in the
words “more advanced.” That Nos. 110 and 141 are from
the same woman about a year apart is especially noteworthy.
The woman was suffering from leucorrhcea and in general
the ova show the same changes within them. Nearly all of
the villi have been destroyed, and the main walls are fleshy
and are invaded by leucocytes. The embryos are dissociated
and atrophied. That the process was slow is indicated by
their menstrual ages. In one the amnion is destroyed entirely
and in the other it is greatly dilated, nearly filling the entire
cavity of the chorion. That two specimens coming from the
same woman should show the same changes in them indi-
cates that the cause of the trouble lies in the diseased condi-
tion of the uterus. There are a number of other specimens
which corroborate this conclusion.

No. 1.] ORIGIN OF HUMAN MONSTERS. III

During the fourth week of development the preskeletal
tissues make their appearance, and through this change the
embryos naturally fall into the two groups under which I am
discussing them. The mesenchyme also becomes more resistant
and does not dissociate so easily. The peripheral nerves are
well laid down and the premuscle tissue is making its ap-
pearance. Thus we have new conditions by which we can
recognize the time at which development was arrested; these
naturally influence secondary changes in the embryo. In these
specimens hydramnios is nearly always found, and since the
embryos usually become markedly smaller when their de-
velopment is arrested it is rational to conclude that hydram-
nios is produced by a continued growth of the amnion and
chorion when the development of the embryo has been ar-
rested. I have found no evidence in favor of the theory that
hydramnios is due to arrested development of the amnion and
dwarfism of the embryo. Were this the case we should find
bones and cartilages in my specimens of the fourth week. In
the specimens given in Table IX we have four weeks’ embryos
in eight weeks’ chorions, not degenerated eight weeks’ em-
bryos in eight weeks’ chorions. The four good specimens
(Nos. 347, 285, 336 and 334) of the end of the fourth week
are of different degrees of degeneration and form an excel-
lent continuous series. No. 347 is from an ovum in which
the mesoderm of the chorion is fibrous, the syncytium being
scanty and mixed more or less with pus. The changes within
the embryo are well marked, the brain being dissociated and
solid and the medulla and cord are dilated. The blood-vessels
are well marked, dilated and filled with blood, which is just
beginning to infiltrate into the surrounding tissues. The other
organs are just beginning to dissociate. The precartilage is
well marked, however, and the rest of the mesodermal tissue
has in it many round cells which seem to have come from the
blood. Many of these cells are in the pleuro-peritoneal cavity.
Conditions are advanced markedly in No. 285. Here the
menstrual history tells us that the pathological process has
been under way for a number of weeks. The mesoderm of

112 MALL. [Vot. XIX.

the chorion is fibrous and between the few villi covering it
there is much mucus rich in leucocytes. The embryo is
atrophic, the tissues, however, being still active, although dis-
sociated. The brain and head are reduced in size, the medulla
is solid and fills the region of the face, and the cord is dilated
and its walls are folded upon itself. The organs are more
dissociated than before, the large blood-vessels and the heart
being greatly dilated and filled with blood. The precartilages
and peripheral nerves are well marked and the remaining
tissue is pretty well filled with round cells. Most of the
epidermis is intact.

The two specimens just described hom to what extent an
embryo four weeks old may dissociate when its nutrition is
partly cut off. In the next specimen (336) the amnion did not
continue to dilate as well as it did in Nos. 285 and 347, but re-
mained clinging to the embryo, as is the case normally at this
time. However, it is pretty well destroyed, being partly
infiltrated with embryo blood-cells. The ccelom is well filled
with granular magma, in which there are many migrating
cells. In form the embryo is curled upon itself and distorted.
Within the central nervous system is dilated and the walls
are folded upon themselves. The liver is completely infil-
trated with blood. Mesodermal tissues seem to be normal.
What is especially noteworthy is the condition of the vascular
system. The heart walls appear normal and the vascular
system is well proportioned and filled with blood. It appears
as if it had functioned until the abortion took place. The
vessels from the embryo through the umbilical cord to the
chorion are cut off and the enlarged omphalo-mesenteric ves-
sels seem to take their place. The walls of the yolk sac are
necrotic, but have in them large blood-vessels, which on one
side spread over into the chorion. The old original circula-
tion has re-established itself and is now connected with the
chorion in this roundabout way. There are in the chorion
two kinds of capillaries, degenerate ones which are connected
with the umbilical vessels and new ones which communicate |
with the omphalo-mesenteric vessels.

No. 1.] ORIGIN OF HUMAN MONSTERS. 113

The other specimen of the fourth week is the remnant of
the embryo from No. 334. Here the destruction is quite
complete, only fragments of a four weeks’ embryo being
found in a small space of a large mole. The piece shows dis-
sociated organs of an embryo much like No. 285.

These specimens give the beginning and the end of dis-
sociated embryos during the fourth week, with an attempt to
remedy the difficulty in one specimen (No. 336), and the
almost complete destruction in another (No. 334). It is
probable that the primary trouble in No. 336 lay in the
umbilical cord.

EMBRYOS OF THE FIFTH WEEK.

The changes in the beginning of the fifth week are quite
similar to those at the end of the fourth week, for the normal
development has advanced but very little. However, toward
the end of the fifth week, when the anlages of the ribs
appear and there is further differentiation in the mesenchyme,
we also find modified pathological processes, which are quite
characteristic, and are not seen in earlier stages. The first
specimens, then, which are about to be described could also
with propriety have been considered with those at the end of
the fourth week. In these we find again the dilated and disso-
ciated central nervous system, dissociation of the tissues and
the organs, infiltration of the liver with round cells, and a
dilated and gorged vascular system. All these changes are
well marked in Nos. 97 and in 251. In No. 251, however,
the pathological changes are so marked that it merits a
special description. The chorion is well enveloped in pus,
showing that an active endometritis encircled it. The head
of the embryo is rounded, solid and filled with a dissociated
brain. The face is practically destroyed and the brain is pro-
truding on the dorsal side of the head. Following the sections
_in order down the spinal cord, it is found that in this the
central canal is distended and the walls partly dissociated.

114 MALL. [Vor. XIX.

TABLE X.
NorMAL EmBryos OF THE FirtH WEEK.
3
2
Specimen. Embryo. Chorion. ab
$<
=
mm, mm. days
Eis (ny) aasesmrinere 8.5 20X12
IN@eut OS iepenerarscriere | 9 Big Se Bis 3 Go) 5 wks.
INON3SOcc meer ec 9 52
INOM 25 Ores 10 Bis Se HO) Se OS
Eeker 2tpe chen cia IO 60
INOS BS. crcuevetaryersts 10 30 X 28 X 15
NOW3.8O a0 eis ai Io 30
EMISE(O'S)eemerecicnee 10.3 Bis oi OR
INGEMDOO Rr teen ore 11 30 X 30 54
NOt arise nasi akare II 40 X 35 X 30
le Gtsia((Si0) le pee io te i it BO 2/7 61
His (97) iti a aes II 30X25
is (RG) inca tere cc ito BOE 7
ING atisOi5 sons sa oe 2 AE ss Qs
as (Sl) cies 2.5 20°27
TABLE XI.
ARRESTED DEVELOPMENT OF THE EMBRYO.
(Fifth Week.)
No. rae Dimensions of Menstrual Changes in the Chorion.
Embryo. the Chorion. ge.
mm. mm. days
97 9 201% 30 £5 61 Fibrous.
135 9 105 X65 x65 Atrophic. Infiltrated by leu-
f cocytes.
251 9 30X25 25 77 Fibrous. Abscesses.
366 9 Fibrous or hyaline.
161 10 Sok 25 x 25 83 Pus between villi.
54 II
133 II 32% 32 %32 65 Normal in shape but fibrous.
288a II 35 e355 sor6 |Fibrous. Invaded by leuco-
weeks cytes and syncytium.
343 12 AR Ka5 ka Fibrous.
177 12
3308 12 60X55 X50 128 | Infiltrated by leucocytes.
330b 12 So. xi5Oea 5 128 | Infiltrated by leucocytes.

348 12 50 X 30X25 Fibrous degeneration.

No. 1.] ORIGIN OF HUMAN MONSTERS. 115

The usual changes are again seen in the vascular system, and
the dissociation of the tissues and organs is well marked. The
mesodermal tissues, including the precartilages and periph-
eral nerves, are more or less filled with round cells, which,
as the epidermis is wanting, have also wandered to the ex-
terior of the body.

Specimen No. 161 is especially interesting, for the inflam-
matory changes around it are no doubt due to the repeated
attempts at abortion by the mother. The woman was already
suffering with leucorrhcea, and it was easy for her to extend
this purulent inflammatory matter into the uterus with the
rubber catheter she had used. While this experiment was fol-
lowed by great activity in the leucoytes and syncytium on the
outside of the chorion, an equally active reaction took place
within the embryo. The head end of the embryo is almost
completely dissociated, but the process is less intense in the
lower part of the body. In general, the changes are similar
to those in the embryos described above.

More intense changes are found in embryo No. 135, in
which the duration of the pathological process must have
been long, judging by the changes in the embryo and
the chorion. The chorion, to which we look for the primary
lesions, is smooth and devoid of villi. The large amnion
within is filled with a jelly-like mass which became firm after
it had been treated with formalin. The atrophic embryo con-
tains a dissociated central nervous system without a brain, the
head being very small and converted entirely into a mucoid
mass. The eyes have sunk deep into the tissue of the head
and contain hard lenses, composed of lens fibers. The an-
terior end of the chorda dorsalis is much enlarged and forms
a mucoid tumor, on either side of which may be seen a large
cartilaginous mass of tissue. Heart and vascular system are
filled with blood, which extends through their dissociated
walls into the surrounding tissue, obscuring the outlines of
the organs and peritoneal cavity. All this shows that devel-
opment ceased a long time before the abortion took place, and
that the tissues simply grew onward in an irregular fashion,
Hels. they dissociated.

116 MALL. [VoL. XIX.

The remaining nine embryos of the fifth week may be con-
sidered together, for in many respects they are alike. In all
of them the bodies of the vertebrz are well outlined and the
precartilages of some of the ribs are laid down. They may
be compared with the normal embryos, Nos. 109 and 163,
whose skeletons have been studied with great care by Bar-
deen. It may be that the first four embryos of this group
belong to the fourth week, for it is certain that their develop-
ment is not as far advanced as No. 163, but they are fully as
large. The slight difference may be due to errors in measure-
ments or to the possibility that pathological embryos of
younger stages may simply “swell” but not develop. How-
ever, the opposite is usually observed.

Specimens Nos. 54, 133, 348, 288a, 343 and 177 show mucn
the same changes in them. The tissues are well dissociated,
with a variety of other changes in the body. In Nos. 54 and
343 the front end of the brain is missing and the ventricle
communicates with the exterior of the body, as if the neuro-
pore were open. In these two specimens, in which the cere-
bral vesicles have been fully destroyed, there are but few
pathological changes in the rest of the body. They may be
compared with No. 256 (Fig. 8, Plate III), in which the
fore-brain was removed by mechanical means, that is, through
rough handling, and is in every respect an anencephalic mon-
SEE.

No. 133 is well dissociated, but in it, as in the rest of this
group, the liver is more like the normal, showing that in
later stages the liver is more resistant than it is in younger
ones. No. 348 shows about the same changes, only that in
addition the embryo as a whole is disintegrating. The de-
formed embryo from specimen No. 288a is from a mole in
which the chorion was found to be collapsed. The position of
the embryo is in the upper right hand corner. In No. 177 the
process of dissociation has outlined the ribs into two zones,
an outer and an inner, although no true cartilage is present.
Back of the eyes, in the occipital region, there are two car-
tilaginous masses, much too well developed for an embryo

No. 1.] ORIGIN OF HUMAN MONSTERS. 117

of this stage, and similar to those found in No. 135. These
changes are given as examples of further development of
some of the tissues after the general growth of the embryo
has come to an end. In No. 343 the fore-brain is destroyed
entirely and the medulla is distended. The outlines of the
organs and tissues are well defined, and they are fairly well
infiltrated with migrating blood cells.

The structure and form of the organs in No. 343 resemble
in many respects the state of things found in Nos. 330a and
330b. These two specimens came from twin ova which were
aborted 128 days after the beginning of the last menstrual
period, thus making the duration of the pathological process
fully nine weeks. The chorions are both fibrous, are envel-
cped in pus and infiltrated with leucocytes. Both embryos
show practically the same changes in them as are found in
several other. sets of twins, which seems to me to be strong
evidence in favor of the theory that the deformed embryos
are due to endometritis. The changes in both embryos are
very much alike and can be described together. The epi-
dermis is intact, but the true skin is hypertrophied, and in
front of the head, in the region of the deformed mouth, the
epidermis shows peculiar thickenings. Both spinal cords are
dilated and their walls are dissociated. The cerebral vesicles
and mid-brain are nearly destroyed, the main portion of the
head being taken up by the hind-brain. The large blood-
vessels and the heart are filled with blood; in 330b the wall of
the ventricle is infiltrated with blood cells and in 330a it is
nearly destroyed by them. The tissues and organs of the
embryos are well dissociated and more or less filled with
round cells. Some of the liver tissue is necrotic.

In reviewing the most marked peculiarities of the path-
ological changes in embryos of the fifth week, it may be noted
that the differentiation of the tissues has made some of them
more resistant than others; the more central tissues show the
least amount of change, and the extremities, head and face
the most, these giving way first. The spinal cord and
medulla show more resistance than the brain and do not dis-

118 MALL. [Vov. XTX.

integrate as easily. The vascular system seems to suffer
more than the nervous system does, but this may be due to
the character of the primary trouble in the chorion, which
probably first made itself felt in the heart. It is clear that
when the heart is affected and stops that the embryo is
then deprived of its nutrition, and under these circumstances
the brain suffers before the spinal cord. Among the tissues
the precartilages and cartilages suffer least of all.

EMBRYOS OF THE SIXTH WEEK.

In the beginning of the sixth week of development the
cartilages of the extremities are outlined, and at the end of
the week some of the ossification centers are present. Coinci-
dentally the peripheral nerves ramify through the body and
the muscle anlages appear. Thus we have before us a highly
differentiated organism, and from now on anything which
affects its nutrition does not produce a like influence in all
of its tissues and organs. The reader has noticed, no doubt,
that the present study is gradually leading in this direction.
First the umbilical vesicle is most resistant, then the nervous
system and now it is the skeleton. At first the blood-vessels
possess the greatest power of growth before they were de-
pendent upon the heart, but later when they are, they appear
to suffer most, and the other structures are only affected in
a secondary way, for they in turn receive their nutrition from
the blood.

The changes in embryos of the sixth week can be followed
with greater ease than those in earlier embryos, for they are
less rapid and there are a larger number of known structures
present to tell the story. In studying the pathological em-
bryos, I naturally compare these changes with the normal in
embryos of about the same age, and as a standard Nos. 109
and 144 are constantly employed (Plate IV, Fig. 10).

No. 1.] ORIGIN OF HUMAN MONSTERS. 119

TABLE XII.
NorMAL EMBRYOS OF THE SIXTH WEEK.
a
Speci | Emb Chorion Es
pecimen, | mbryo. orion. 2
=
|
mm, mm. days
lab Sail Giop le oeoaowe 12.8 40 X 32
INO). Bice a oopeec 1a 37
1: as ty ae ee a 13 30k 2hke a8 22
lake (WE) \eSaloaeae 133 64
Iba (839) ign Saomor | 13.6 35 x 28 63
INQEPAAG ena evel sons’ I4 40 X 30 X 30 60
INOS 20 Precis ee 38 14 Py ORONO
AN Ore SOG Goss ave tc Yoke 14 55
INO Rr OW rspeetans 14.5 30 X 30 X 30 65
ING EOS tise o's «cts 15 94
ise (Dt) ercettertere 15 45 X 40
AISA ere eee se sts 15 25 x 28
No. 256. Bgkie’s 16 60
ING 2. G07 secu see > 16 AG 25 25
Elise (iohis): *ssc 6s. ay} 51
INO BOO octets sts ng) 54
icli(o ige-o as Peete reer 17 Bema 26

The first pathological specimen which I shall consider is
No. 311, an unusually good one, for it is well preserved and
there is every indication that the changes in it were produced
gradually. Unfortunately, the menstrual age is not known, but
I am of the opinion that it must be at least fifty days, that is,
about two weeks more than normal embryos of the same
size and degree of development. The chorion is covered with
villi of unequal size, which show all degrees of activity, some
being hypertrophic and others atrophic, fibrous and more or
less invaded by leucocytes. The surrounding inflammatory
process has gradually destroyed the villi. The condition of
the vessels within the villi also indicates that the process of
destruction has been gradual; the large villi contain fairly
well developed capillaries, and the small ones are devoid of
them altogether. The umbilical cord is enlarged in its center
and very small at its attachment to the chorion. In general,
it is fibrous and its blood-vessels are contracted and empty.
The enlargement in the cord is due to the mucoid masses

120 MALL. [VoL. XIX.

TABLE XIII.
ARRESTED DEVELOPMENT OF THE EMBRYO,
(Sixth Week.)

No. area. | Dae ee of | ped cu | Changes in the Chorion.
mm. mm. days.
311 124 36 X 30 X 30 Fibrous.
69 13 70 X 40 X 20 Atrophic and fibrous
174 13 25 xX 2560. oie 56 Atrophic. Invaded by syn-
cytium.
Olen eS ee
2 I SOG 5m aline.
ae 2S a seid ss : cca Mucus and pus be-
tween villi.
aris 13 Fibrous.
276 134 TORRES In exe a16 80 Fibrous.
232 14 AG ooh axes Fibrous (?).
262 14 SOx 15% 115 Villi invaded by leucocytes.
270 14 40 X 30 X 20 Fibrous and atrophic.
305 | 14 | =
341 14 70 X 60 X 50 Fibrous. Some villi cedema-
tous. (Twins in a single
chorion.)
81 i GNX 55 x35 84 Atrophic, infiltrated with leu-
cocytes.
132 15 42) xX 30 89 Atrophic.
142 15 50 X 40 X 30 129 Fibrous. Invaded by syncy-
tium.
200 15 Siew 2 5 oes Fibrous.
212 15 Very large 189 (?) ,
364 16 90 X 50 X 4o 99 Fibrous and atrophic.
07 16 60 X 50 X 30 86 Fibrous. ;
207 16 TOR AG x AS Chorion hyaline(?). Syncy-

tium irregular. Decidua in-
filtrated with leucoytes.
(Twins in a single chorion.)

339 16 50: X 20.30 Hyaline. ;

344 16 45X45 X45 Fibrous and atrophic.

203d!" 35 27 Oa Normal(?).

188 te] 45 X 40 X 40 66 _ Very fibrous.

215 0] 45 X 40 X 4o 12 wks. Fibrous.

357 Ly 90 X 40 X 40 13 wks Fibrous. Invaded by syn-
cytium.

within, seen so often in pathological specimens. Within the
embryo the vascular system and heart are much dilated and
filled with blood. The whole condition of affairs indicates that
the circulation was interrupted shortly before the abortion
took place. . .

The embryo is imbedded in an irregular mass of granular
magma, and from its external form it seems to be nearly
normal. However, its neck is kinked too much in front, and

No. 1.] ORIGIN OF HUMAN MONSTERS. 121

sections show that there is an active growth of scar tissue at
this point. In general, all the tissues are more or less dis-
sociated, the cartilages and precartilages being most resistant.
The walls 6f the heart and blood-vessels are not sharply
defined and many blood cells spread from them into the sur-
rounding tissues. The central canal of the spinal cord is dis-
tended and the peripheral nerves are well infiltrated with
round cells. The dissociation of the fore-brain and mid-brain
is pretty complete, and the walls of the medulla are spreading
out into its ventricle. In general, the head is reduced in size,

The most marked secondary changes are seen in the
mesenchyme of this specimen. At points there are fibrous
thickenings in the skin, which frequently form papillomata,
covered more or less with a single layer of epithelium. In
front the face and chest have grown together, the point of
union naturally closing the mouth, including the tip of the
tongue in a mass of round cells.

I picture the whole process as follows: In general, the de-
struction of villi in the chorion is followed by fibrous atrophy
of the umbilical cord and arrest of the heart beat. After the
circulation has ceased the organs and tissues gradually dis-
sociate and blood cells enter the tissues. Probably before
the changed conditions had reached this extreme state the
brain began to dissociate and became solid, and the face
atrophied and united with the chest below. The changes in
the rest of the embryo were not marked until the circulation
ceased altogether. It is clear, however, that the brain dis-
sociates before the rest of the embryo, for we constantly find
in it more radical changes than in other portions of the
embryo.

Practically the same pathological changes described for
specimen No. 311 are found in Nos. 375, 69, 174, 182 and
325. No. 174 has horn-like processes and No. 182 has a
straw-colored necrotic mass in front of the head. No. 325
shows still more advanced changes, the necrosed liver is dis-
integrating, this process having begun in 311. From all
appearances this embryo has been dead for a long time, which
is also indicated by its menstrual history.

122 MALL, [VoLt. XIX.

Embryos 14 mm. long repeat the story given by those
13 mm. long. The least amount of change is found in No,
270, which is nearly identical with No. 311. However, the
brain is not quite so solid, the dissociation of the tissues of
the body is about of the same degree and the frontal process is
united to the thorax below. Within the medulla there are
papilliform sprouts of nerve tissue which extend into the
ventricle, just as in No. 311. No. 346 may be a little older
than No. 270, but the changes in it are not quite so advanced,
nor has the frontal process united with the thorax below. The
head and neck are also straight in Nos. 262 and 232, the
changes in the tissues being very advanced. In No. 262 the
cerebral hemispheres form a solid mass, which looks like an
abscess, the medulla is much distended and its thin anterior
wall protrudes through the mouth. Much the same condition
is found in the cylindrical head of No. 232. In it the large
fifth nerve may be seen running to the surface of the body,
and acts as an index to tell how much of the head has become
atrophied. The arms and legs are gorged with well stained
round cells, indicating that secondary changes have taken
place in them.

The marked changes which have taken place in the brain
and head have met their end in embryo No. 276. Here we
find advanced changes in the head, but the body is much like
the other specimens. The medulla is greatly distended and
fills entirely the rounded top of the body, the rest of the brain
having been expelled through an opening which is still pres-
ent. Around the edge of it the epidermis is piled upon itself,
apparently attempting to heal the wound. The severe changes
in the chorion and the long duration of the process have ended
by destroying entirely the brain and the top of the head,
leaving the body of the embryo capped only with a remnant
of a head containing a dissociated medulla.

Most radical changes are found in specimen No. 365. The
embryo is within a fibrous chorion. There is spina bifida,
iniencephaly and anencephaly. The mouth is closed completely
by the tongue becoming adherent on all sides. The tissues of

No. 1.] ORIGIN OF HUMAN MONSTERS. 123

the body are necrotic, and most of them are infiltrated with
round cells, and there is irregular growth of the mesodermal
tissues, especially those of the tendons and perichondrium.

The embryos of the second portion of the sixth week, that
is, embryos 15, 16 and 17 mm. long, may be brought together
in three groups, according to the degree of change in their
tissues.

In the first group there are three specimens, Nos. 263d,
132 and 188. In these the first changes are seen after the
circulation has been cut off. The tissues and organs are
sharply defined, the vascular system is distended with blood,
and more or less round cells are found inthem. ‘The fore-brain
is solid and the medulla and cord are somewhat dissociated.
In No. 263d the brain has broken through the palate and a
considerable amount of it has escaped into the mouth. How-
ever, this embryo is macerated somewhat and is slightly torn
in the region of the back, and the brain capsule may have
been torn open by mechanical means. In embryo No. 132
the extremities of the right side of the body are atrophic,
while those of the left appear to be normal.

In the second group of specimens (Nos. 344, 137 and 357)
the changes in the embryo are more marked. The blood-
vessels are gorged, their walls are not sharply defined and the
blood cells extend from them into the surrounding tissues. In
No. 344 the brain is reduced in size, is solid and occupies but
a small portion of the head. The medulla is dissociated and
expanded and has been pushed forward, almost reaching to
the front part of the head. Below this the jaw is kinked over
the chest, with which it has formed a secondary union. Over
the regions of the fore-brain and mid-brain there are spots
in which all of the surrounding tissue is wanting entirely,
thus exposing the brain freely at these points.

The last group includes the embryos in which the changes
are extreme, and includes seven specimens, Nos. 81, 142, 200,
212, 215, 339 and 364. In them the tissues are well disso-
ciated and more or less filled with round cells. The usual
changes are seen in the central nervous system, the spinal

124 MALL. [Vou. XIX.

cord being dilated, while the brain and medulla are solid. In
these embryos the dissociation is carried to an extreme de-
gree, the extremities being atrophic, and in some of them the
embryos are pretty well disintegrated. In Nos. 81, 200 and
212 the face and the top of the head are composed of a thick-
ened mass of necrotic tissue, and the changes in the central
nervous system are extreme. The embryo of specimen No.
215 is broken into a number of pieces which barely hold
together.

Specimens Nos. 142 and 339 are quite typical ones of this
stage, for in them the dissociation of the tissue is pretty
complete, and the outlines of the organs are quite obscure.
Most of the blood has left the blood-vessels and is in the
surrounding tissues. The fore-brain is completely separated
from the medulla in No. 339, and in general it is reduced
“in size: some of it may have escaped through the front
of the head, which is broken off. The medulla is rounded at
its free end, is distended and fills most of the head. Had
this specimen lived it would probably have formed an anen-
cephalic foetus. But in order to have lived through gestation
the change in the whole embryo could not have been as radical
as it is in this specimen, and judging by the anatomy of anen-
cephalic monsters the destruction of the brain does not, in
all probability, begin until some time after the sixth week.
In No. 142 the changes within the embryo are also extreme,
but the remnants of the organs remain within the body.
However, the external features of the embryo have van-
ished entirely, the arms and legs having atrophied completely.

No. 364, which belongs to this group, is a most remarkable
specimen, for it forms a typical monster and is accompanied
by an excellent history. The ovum, covered with a few
ragged villi, is from a first conception in a woman who had.
been married four years. It was from a natural abortion,
the woman being very anxious to have children. In general,
the woman appears to be healthy, but she has suffered from a
variety of troubles with her uterus and vagina, which are
given at greater length in the history of the case. The usual

No. 1.] ORIGIN OF HUMAN MONSTERS. 125

changes are found in the chorion, indicating faulty implanta-
tion and inflammation. The embryo, whose menstrual age 1s
99 days, corresponds in length with a normal embryo 40 days
old, that is, having a menstrual age of 68 days. In other
words, the pathological process in No. 364 has been under
way for fully a month.

The large blood-vessels and heart are still filled with blood
and there is a general infiltration of the tissues with round
cells; the vessels of the umbilical cord do not reach to the
chorion, showing that the nutrition of the embryo has been
cut off entirely. There is a general destruction of the tissue
due to, or causing, the irregular growth of the embryo. This
is especially well marked in the brain and spinal cord, which
are rudimentary, are converted into a mass of vascular con-
nective tissue capped by a rudimentary shield of brain tissue,
as is illustrated in the figures. .

There is pronounced hare-lip, the ears are displaced, and
there is exomphalos, spina bifida and pseudencephalus; the
latter is no doubt the forerunner of anencephalus.

That the pathological conditions found in most of the
‘specimens reported in this contribution are not of germinal
origin, but rather due to the changes in the environment of
the ovum, as may be brought about by endometritis, is illus-
trated beautifully by two sets of twins of the sixth week,
which I have been fortunate enough to procure—one from
Professor Brodel and the other from Professor Minot. To
these may be added the twins of the fifth week (Nos. 330a
and 330b), the two sets of specimens, each from the same
woman (Nos. 110 and 141 and 308 and 325), kindly sent
me by Drs. West and Ballard. These groups of specimens
speak volumes against the germinal theory of merosomatous
monsters. The facts of the case have been discussed under
a special heading above, and they need not be repeated here.
However, if the law of probability and the normal condition
of the embryos in earlier pregnancies were not taken into
consideration, they could be explained by the germinal, just
as well as by the environmental theory. The conclusive evi-

126 MALL. [VoL. XIX.

dence in favor of monsters being due to a change in the
environment, which causes faulty implantation of the ovum,
thus impairing the nutrition of the embryo, is found in the
study of the embryo in tubal pregnancy, where 96 per cent
of them are monstrous. Were the primary trouble in the
germ, no more pathological ova should be found in tubal than
in uterine pregnancies. Furthermore, all this is vouched for
by comparative experimental teratology.

To be sure, polysomatous, pansomatous and those meroso-
matous monsters that are due to an arrest of development at a
very early stage (monopodia) and those variations of an
hereditary nature (polydactyly, polymastia) and ordinary
anatomical anomalies, cannot be due to changed environment
at a stage so late as the fourth week of pregnancy, and some
of them, like variations in the hands and feet especially, are
markedly hereditary, and therefore germinal in nature. How-
ever, this digression is not altogether to the point; the mero-
somatous monsters, the subject of this report, are due to a
direct experiment which is equivalent to the mechanical re-
moval of most of the villi of the chorion.

The two sets of twins (Nos. 207 and 341) are alike in
many respects, for each set is contained in a single chorion.
The degree of development and degeneration is about the
same for each set. In No. 207, the younger one, the process
was severe but not of long duration, while in No. 341 the
cpposite must have been the case. In both sets the organs
and tissues are well dissociated, showing the usual changes
so often seen in the embryos studied. When I first took up
the study of pathological embryos I was inclined to the idea
that the changes in the chorion were often of a secondary
nature, but as the specimens became more and more numerous
and were preserved better and better, which enabled me to
study them with greater care, this idea had to be abandoned.
Now it is clear that we are dealing with a simple experiment
which must bring about the changes in the ovum and embryo
to make it pathological. The greater number of ordinary
abortions in the first month consists of ordinary pathological

No. 1.] ORIGIN OF HUMAN MONSTERS. 127

embryos. The changes in them are so radical that it is im-
possible for but few of them to develop into monsters had
they not been aborted. However, it is not difficult to imagine
specimens in which the changes are not so extreme, that is,
they are due to minor changes in the chorion, which may
retard the development of a part of the embryo, and after-
wards become corrected, thus favoring the growth of a dis-
torted embryo into a merosomatous monster. In nearly all
of these embryos there is a tendency for the liquor amnii to
increase in quantity, a condition which must also be viewed
as a secondary process, and, therefore, cannot be of funda-
mental significance in the production of monsters.

It is evident from the study of pathological ova that in
order to complete the chain of evidence it will be necessary to
study anew and with much greater care the membranes of
embryos which appear to be normal, for in them we shall no
doubt find the very earliest stages of monsters which could
have existed and grown throughout pregnancy. The recent
publication of Fischel, as well as the more careful study of
some of my “normal” embryos (Nos. 6, 10, 11, 12 and 80),
indicates that embryos of this kind will probably serve to
clear up entirely the subject under discussion.

EMBRYOS OF THE SEVENTH WEEK.

In the seventh week, when some of the bones are ossified,
the embryos have reached a stage in which interference with
their nutrition does not shatter all of their tissues at once.
The effect upon the central nervous system is still more pro-
nounced than that upon the other tissues, and even at this late
period the dissociated structures continued to grow in an
irregular fashion.

The number of specimens at this time is also greatly
diminished, as is naturally expected, for the younger ova are
attacked early by the infected mucous membrane of the
uterus and few of them survive until the seventh week. It
follows, then, that as gestation continues pathological ova are

128 MALL. [VoL. XIX.

less and less likely to be found. To be sure, the diseased
specimen may be retained in the uterus for a long time as a
mole, with or without an embryo, but if the chorion is not
affected during the first few months of pregnancy it is likely
to go on to full term, or if it is aborted so late it rarely con-
tains a dwarfed embryo. Furthermore, infections of the
uterus are infrequent after pregnancy is well under way, and
in case it does take place, the probability of its attacking the
whole chorion is slight. The embryo would probably with-
stand the insult, since it is now more differentiated and more
resistant.

There are in my collection ten pathological specimens of
the seventh week and half of them may be normal, at least
the changes in them are but slight. Furthermore, after the
seventh week there is but one pathological specimen a week
until the fourteenth week, and none from this time until the
end of pregnancy.

A summary of the embryos brought together in the various
tables is as follows:

Vesicular forins 2 Ce oe tere oe eee 19
Ova with neither embryo nor amnion ........ 2

Ova with amnion but without embryo ........ 15
Pathological embryos of the second week ...... 4
Pathological embryos of the third week ...... 18
Pathological embryos of the fourth week ...... 21
Pathological embryos of the fifth week ....... 13
Pathological embryos of the sixth week ....... 2

Pathological embryos of the seventh week ..... 10
Pathological embryos of the eighth week ...... 2
Pathological embryos of the ninth week ...... I
Pathological embryos of the tenth week ....... O
Pathological embryos of the eleventh week..... I
Pathological embryos of the twelfth week ..... O
Pathological embryos of the thirteenth week .... 1

Pathological embryos of the fourteenth week .. 1

Now r] ORIGIN OF HUMAN MONSTERS. 129

This infrequency of pathological ova as pregnancy con-
tinues is not at all remarkable, for human monsters at term
are not so very common, and while they are produced in the
early months of pregnancy, at first the changes in them are
slight, and consequently they are not aborted. The pathological
ova in which the changes in the embryos are very severe are
the kind that are aborted and the ones which I have been con-
sidering. However, the reactions in them give us a hint of
what takes place in the early stages of monsters that continue
to develop until the usual end of pregnancy.

Of the specimens of the seventh week, No. 128 is normal
in every respect with the exception of the presence of a fairly
marked magma reticulé in the amniotic cavity. This I
have not found in other normal specimens, and, since it is the
earliest and most constant sign of a diseased embryo, it is
worthy of mention. No. 307 is also no doubt normal,
although small clumps of leucocytes are found between the
villi and at points they are found in the mesoderm of the
chorion. Nos. 268 and 338a may be normal, although some
tissue changes are seen. These may be due to maceration, for
the specimens are not especially well preserved. Dissociation
may have begun in No. 345, but it is more or less obscured by
the extensive maceration which accompanies it.

Marked pathological changes are found in specimens Nos.
320 and 94. In them changes are found in the chorion, show-
ing that the attack by leucocytes has been very severe. In
one (No. 94) there is a great amount of granular magma
within the amnion. The tissues of the embryos are disso-
ciated, the brain and cord being nearly solid. In general, the
boundaries of the organs are obscure, their tissues being more
or less infiltrated with round cells. We have in these two
embryos conditions found so frequently in younger specimens.

No. 293 is a specimen of unusual interest, for the sections
show that most of the embryo is normal, only one portion
of it being affected. The blister upon the back was
recognized by Dr. Lamb when he opened the chorion. It is
filled with a granular albumen, and at its edges burrows into

130 MALL. [Vou. XIX.
TABLE XIV.
NoRMAL EMBRYOS OF THE SEVENTH WEEK.
| :
| SS
Specimen. Embryo | Chorion. % =f
| 3
mm. mm. days

IN@nitGiag Yoneno-6 c 18 40 X 30 X 20

No. 42. 18 35

INOSLO Ob yarns 18 2 mos.

NOMS a 18.5 40 X 30

INO, 26) «sisueesehentiers 19 50 X 30 X 20 47

INO M2206 Geet nerr 19 49

INOn ESSts wane Rael 20 50 X 43 76

IN Oe 2 2ietonors cece cie 20 35 X 30 XK 30

No. 240 20 FORA OSes 0

No. 194.++-.4+-+ 21 Aiea AS

Minot? rei aetes 22 5a

ELIS i) ae aS niet 22 56

INOS 9 cus sonie els 23 30

INOS 242 ators 2B OR FO), 59

Nich <Oomoauraoac 23 66

tis) (GW t) ieee ace 23 55 X 50

IN Oe 7ighacthsc iblene ote De 40 X 30

iNet) meen irae on 30 65

Isbe (Uli) Goodasc 22 55 os 50

IN@AOMRe acta oni: 24 77

No. 31 24 Som goma30 68

INO WEN Reser. ute 24 60 X 45 X 40 84

TABLE XV.
ARRESTED DEVELOPMENT OF THE EMBRYO.
(Seventh Week.)
Length of} Dimensions of | Menstrual s 7

No. Gs a eee | nee | Changes in the Chorion.

320 18 70 X 50 X 40 Some fibrous. Ovum swollen
and a few masses of leuco-
cytes.

338a 18 aseas 6 to 8 wks. | Normal.

293 19 30r4

months

345 19 60X 50X50

94 20 50 X 40 X 30 Atrophic and invaded by leu-
cocytes.

128 20 50X43 76 Normal.

201 20 Fibrous and invaded by leu-
cocytes and syncytium.

307 20 40 KX 40 X 40 Invaded by leucocytes.

268 22

226 24 60 x 60 X 30 87

No. 1.] ORIGIN OF HUMAN MONSTERS. 131

the mesoderm, which is well infiltrated with round cells. The
“inflammatory” process extends along the middle of the back
to the top of the head. Immediately over the cord, in the
middle of the back, the infiltration of cells extends throughout
the mesoderm and includes the meninges of the cord, showing
a similarity with the changes in the case of spina bifida in
the embryo described recently by Fischel (Plate 1). It cer-
tainly would be very easy for a localized affair like this to pre-
pare the way for the production of spina bifida. Possibly in
the course of time, after my pathological collection contains
thousands of specimens, intermediate stages will be found
which will show that the changes found in this embryo favor
the production of monsters with spina bifida.

Another embryo in which the spinal canal is broken open
behind (No. 226) shows extensive alterations in its tissues.
The changes in the chorion indicate that the circulation within
the embryo had ceased some time before the abortion. Its
mesoderm is fibrous and almost devoid of blood-vessels.
Between the amnion and chorion there is a iayer of organized
blood from the mother, showing that there must have been a
rupture some time before the abortion.

The external form of the embryo is interesting, the trunk,
extremities and cord being normal in form, while there is a
marked defect in the head. Here on the dorsal side the de-
structive process has also included the upper part of the
spinal cord, producing complete spina bifida. The rest of the
central nervous system is still intact, but the cerebral vesicles
are reduced in size and are exposed to the exterior of the
body. The free end of the upper part of the cord is broken
quite abruptly, while that of the lower part of the medulla is
rounded off, 7. ¢., it appears to have healed over. The larger
portion of the cervical cord is missing; it may have escaped
through the dorsal opening.

There are marked changes in the tissues of the body, which
may be due to maceration rather than dissociation. The con-
nective tissues, including the bone and the vascular system,
are well preserved, with more or less round-celled infiltration

and possibly some fibrous thickening.
9

132 MALL. [VoL. XIX.

A more advanced stage of the conditions found in No. 226
may be seen in No. 201, which in addition has cyclopia. In
this specimen there are marked changes within the chorion to
account for the degeneration of the embryo. The villi of the
chorion are intermingled in irregular order with blood, fibrin
and pus, and the mesoderm is fibrous and more or less infil-
trated with leucocytes and syncytial cells.

The form of the specimen is that of a younger embryo,
but the ossification centers of the maxilla, mandible, clavicle
and humerus are present. The epidermis is nearly com-
plete, thickened at points, but wanting over the top of the
head. The mouth and anus are obliterated and the coils of
intestine form a single mass, into which the entodermal cells
ramify. In form the thoracic region, vascular system and
liver are normal, although the cells of the latter are necrotic.
Throughout the embryo there is an extreme growth of meso-
dermal tissue, apparently that of the precartilage being the
most active. This newly-formed tissue seems to have invaded
the embryonic muscles which are more or less destroyed.

The changes within the central nervous system are extreme,
the brain being greatly deformed and separated by a growth
of connective tissue from the spinal cord below. The cap-
like process upon the head contains the medulla and mid-
brain, which are well dissociated, partly necrotic and partlv
infiltrated with round cells. On either side of this there are
two degenerated cerebral hemispheres which communicate in
front of the medulla. The spinal cord begins quite abruptly
in the upper cervical region, and ends in a marked fibrous
tumor, one-half millimeter in diameter, in the upper lumbar
region. In the lumbar and cervical regions the spinal canal
is filled with mesodermal tissue rich in blood-vessels. Here,
however, spinal nerves are present, showing that the destruc-
tion of the spinal cord is of recent date.

The two eyes form a single hour-glass-shaped body, with
a double retina, two lenses, a single choroid and a single
median optic nerve, which does not reach to the brain. Be-
tween this and the ear and tongue there are a variety of

No. 1.] ORIGIN OF HUMAN MONSTERS. 133

structures—muscles and nerves—which are difficult to trace.
Some nerves pass to the epidermis and may represent branches
of the fifth, and one forms a commissure across the median
line. At any rate, there has been a great deal of shifting, and
it is natural to think that the eyes did likewise, as is the case
in the experiments on Fundulus, mentioned above.

EMBRYOS OF THE FIGHTH WEEK AND OLDER.

There are but two specimens of the eighth week (Nos. 79
and 152), one about 56 and the other 57 days old. Both are
strangulated embryos imbedded in a mass of granular magma
with the chorion more or less infiltrated with leucocytes. No.
152 is from a woman suffering with endometritis, this being
her third successive abortion, each of which took place during
the third month of pregnancy. In this specimen the umbilical
cord is thin and very much twisted, a condition which might
also interfere with the nutrition of the embryo.

The bodies of the two embryos are more or less altered, the
greatest change being found in the central nervous system, as
found in so many of the younger specimens. The vascular
system is dilated and there are clumps of blood cells in the
surrounding tissues. In No. 152 the connective tissue appears
to be more fibrous than is normal, the cutis being more or less
hypertrophied.

The remaining specimens may be considered in two groups:
(1) Those with a tendency towards club-foot, the most com-
mon malformation, and (2) those tending towards partial
destruction of the central nervous system, also a very common
malformation. At the present time, I cannot do better than
to describe these specimens in regular order, for there are not
enough specimens to allow following the changes from one
to the other with any degree of certainty. Table XVII shows,
however, that the placentz are involved in all cases in which
they were studied. The villi are more or less fibrous or hya-

134

Specimen.

MALL.

TABLE XVI.

[VoL. XIX.

NorMAL EmMpryo oF THE EIGHTH WEEK AND OLDER.

3 nee) 3
; ne : Bad : a
Chorion. tH OO Specimen. iB | Chorion., B do
aq ee aq
os) | ®
mm. days mm. mm days.
94 || No. 315 47 63
45 X 40 No. 105 48 83
40 75 No. 184 Re) || Oe) >< iy aes
70 X 60 X 50 No. 151 52 | 80x 60 x 60
64 No. 169. 52 110
AOP=sG 2m No. 139. 55 | 80x 65 x 4o 79
40 X 30 X 30 No. 326 55 i
75 || No. 267. 59 84
5° X 40 No. 30.. 60 Wa
71 No: 273; Gof, "76 50: m0 56
60 X 45 X 20 No. 92. 70 98
57 Now 23°. 70 65
50 X 35 69 No. 300 he 14 wks
68 No 34h7.<) | 80 104
66 No. 172 80 103
60 X 50 X 40 78 No. 125 83 84
AOE Oeans No. 308. 84 IOL
9 wks Noia3%e go 64
61 No. 146 95 115
77 || No. 39 95 IOI
70 X 60 X 50 No. 117. 100 III
VOX Ona 710 No. 394. 105 125
82 No. 138 wine 127
2 No. 355. 113 14 wks
89 No. 126 125 125
60 X 50 X 40 78 No. 149 130 126
44 No. 46.. 135 140
36 No. 356 150 130
84 No. 98.. 160 125
60 X 40 X 30 No. 359. 160 156
80 x 60 x 60 78 No. 354 190 178
65 X50 No. 121 210 190
68x 50x 50 83

line, usually infiltrated with
tacked by syncytial masses.

thin and much twisted.

leucocytes, and sometimes at-
The umbilical cord is usually

It appears as if the beginning of the
trouble lay in the chorion or placenta, which was gradually
poisoned by the products of inflammation in the uterus, and
in the course of time this resulted in fibrous degeneration of
its villi, main wall of the chorion and finally the cord. As
a result of malnutrition, the tissues of the embryo grew in

No. 1.] ORIGIN OF HUMAN MONSTERS. 135

TABLE XVII.

Length of| Dimensions of | Menstrual 5

oy Embryo.| the Chorion. | Age. paren.

152 31 OX 42X35.) 70 Fibrous and invaded by leu-
cocytes and syncytium.
| Cord thin.

79 32 50 X 50X50 gt Invaded by leucocytes and
syncytium.
124 35 90 X 75 X 50 126 Abscesses in the placenta
| Cord thin and twisted.
316 44 Cord thin and fibrous.
230 57 75x00 x 50° | 7 WOS:
286 60 LOO! xy5ok 40) 225 Hyaline and infiltrated with
leucocytes and syncytium.
Cord thin and twisted.

308 84 IO | Fibrous (?) Muco-purulent
substance between villi,
Cord twisted.

261 go 1207 OX 70 | Very fibrous.

an irregular fashion, the central nervous system and extremi-
ties suffering most, as is the case in numerous younger
specimens. Later the heart stopped, and then the most resis-
tant cells of the body continued to grow for a time until
everything came to a standstill.

These changes are beautifully illustrated in specimen No.
124, which is also described and well pictured in my first
paper upon this subject. This embryo is of the nine weeks’
stage, with a chorion twice too large and a menstrual history
five weeks too long. This means that after the ninth week
of pregnancy the embryo ceased to grow, but the chorion
continued to expand at the same rate as the normal one
grows, until the fourteenth week, when it aborted. What is
also noteworthy is that the amnion did not keep pace with
the growth of the chorion, leaving between them a large exo-
coelom. The placenta is more or less diseased, that is, infil-
trated with leucocytes, which at points produce small ab-
scesses. ‘The embryo itself has atrophic ears, club-hands and
club-feet. After the embryo had been in my possession for
seven years it was cut into sagittal sections, which, unfortu-
nately, did not stain well. However, they show that the skin
is more fibrous than normal, being infiltrated with round

136 MALL. [VoL. XIX.

cells, especially in the deformed extremities, where all of the
structures are involved, forming syndactyly.

Changes similar to the ones found in No. 124 are seen
again in No. 316. Unfortunately, I failed to obtain the mem-
branes or any history of this specimen, so its story must be
told by its form and structure alone. The feet and one hand
are club-shaped, and the other hand is spread out and is
attached to the side of the head. The skin is thickened and
much of the epidermis has fallen off. At points the epithelial
cells form mounds without any tendency towards horny
changes in them. The muscles, blood-vessels and nerves of
the extremities are converted into one fibrous mass of spindle-
shaped cells, giving much the appearance of myomatous tissue
infiltrated with round cells. The cartilages are hyaline, and
bone has formed in the center of the calcaneum. The hand
has grown to the side of the head, the epithelial coverings
having united. The true skin is composed of a mass of round
cells.

No. 230 shows about the same changes, with additional
“records” in the chorion, including the menstrual age.
Together they show that the pathological process must have
been under way for at least three months. There are some
leucocytes in the chorion and the cord is thin and twisted.
The tissues of the embryo appear normal, but they do not
stain well, and the changes in the hands and feet appear to
have been caused by mechanical twisting after the death of
the embryo.

No. 286 is a similar specimen. The chorion is hyaline,
infiltrated with leucocytes, and is attacked by syncytial cell
masses. However, sections of different portions of the em-
bryo show that its tissues are practically normal, which indi-
cates that its death must have been sudden and not gradual.

The oldest specimen of this group is No. 261, which must
also have been dead for a considerable time. The villi of
the placenta have undergone fibrous degeneration and are
devoid of syncytium. The cord is twisted, is of normal size,
and at its attachment to the placenta is somewhat fibrous.

No. 1.] ORIGIN OF HUMAN MONSTERS. 137

Its blood-vessels are filled with blood. The decidua is com-
posed of large sinuses, which are well filled with round cells.

At this place it may be well to introduce the description
of a specimen (No. 308) which may prove to be of unusual
value. In every respect it appeared to be a normal one about
100 days old, but the amniotic cavity was found filled com-
pletely with a mass of granular magma which was easily
brushed aside to expose the embryo. The umbilical cord was
found wrapped around both of the arms like a pair of shoul-
der braces, as the figure shows. Sections from the middle of
placenta, at the point of the attachment of the cord, show that
there is a muco-purulent mass between its villi, which contain
many fragmented nuclei.

It may be that the poisonous condition of the uterus stimu-
lated the embryo unduly, which in its gyrations got well
wrapped up in its own cord. This naturally affected its nutri-
tion, the first sign of which is the presence of granular
magma. Had it not been aborted it would probably have
ended like some of the others just described.

In numerous younger embryos a destruction of the brain
and cord were noticed, and in a few of them the brain was
extruding from the head. Yet all these changes were by far
too severe to end in anencephalic monsters at full term. In
nearly all of these specimens the changes in the central nervous
system followed the cessation of the heart beat, and naturally
such embryos could not continue their development; at best
they formed moles. At any rate, the changes in these embryos
show in a most radical way the reactions of the various tissues
when the circulation is gradually stopped.

However, development cannot continue long if the infec-
tion of the chorion is severe, and, therefore, we find but few
older specimens of pathological embryos in a relatively large
collection. Usually these appear to be uninteresting, are mis-
placed or are thrown away. This has not been the case with
my collection, and in it there are but few older pathological
embryos. If a variety of merosomatous monsters are due to
endometritis, we should expect to find them in diminished

138 MALL. [Vov. XIX.

number as pregnancy proceeds, for it is likely that changes
which arrest the circulation in the embryo, or feetus, will
soon end in abortion. Therefore it is to be expected that a
small number of pathological embryos develop into well-
formed monsters.

In specimen No. 293 we have, however, conditions which
might end in a typical spina bifida, for the tissues over the
spinal cord are infiltrated with embryo’s blood and are being
destroyed. The epidermis is intact. Had this embryo not been
aborted the injury in it is sufficient to permit of an irregular
growth of the cord to form spina bifida occulta.

In specimens Nos. 201 and 226 the changes in the central
nervous system are very pronounced, and had they not been
quite so severe it is easy to imagine their growth, at full term,
into a cyclops foetus in the first case and into anencephalus in
the second case.

Specimen No. 295 has in it changes which, if extended,
could affect the cerebrum, and I am inclined to the belief that
most cases of anencephaly begin in these later stages rather
than in very young ones, for if they did not how could a
relatively normal base of the skull develop in them? In this
foetus correlated development has given form to all the bones
of the skull, and the proportion of those of the base would
not change very much in case the vault and brain were
destroyed, as is found in typical anencephalic monsters at
birth. Questions like these are open to investigation and will
give us the key by which we may determine at what time in
development anencephaly begins, or whether the time is
at all constant.

LAID 1

DESCRIPTION OF THE SPECIMENS
AND THE FIGURES.

The description of each specimen is complete in itself,
giving its main data, which were obtained from my note-
books as well as from the specimens and their sections. Their
numbers correspond with those in my catalogue.

The measurements of the embryo are as follows: C.R.,
crown-rump or sitting height; C.H., crown-heel or standing
height; and A./., neck rump or length of the spinal column.

These specimens, with others which I am collecting, will be
deposited in the Wistar Institute, where they may be studied
by investigators interested in teratology.

DESCRIPTION OF THE SPECIMENS AND. FIGURES.

; No. 6.

Ovum, 40 mm. in diameter; embryo, C. R., 24 mm.

From Dr. C. O. Miller, Baltimore, October 27, 1892.

This specimen was obtained through the kindness of Dr.
C. O. Miller, from whom the excellent specimen, No. 2, was
secured some time before. (See JOURNAL oF MORPHOLOGY,
Vol. 5, p. 459.) Both specimens’were removed from the

Fic. 6a.—Reconstruction of the body of the embryo. % 8 times. I-12,
dorsal ganglia; SC, suprarenal body; S, stomach; C, cecum; VW,
Wolffian body; K, kidney; L, liver.

142 MALL. [Vor. XIX.

uterus by self-inflicted mechanical abortions, which the woman
was in the habit of performing upon herself and which finally
caused her death. Dr. Miller informs me that when he was

Fic. 6b.—Diagram of the lower part of the spinal cord through the vesicle
protruding from its ventral side. S°, fifth coccygeal nerve with its
ganglion.

called to visit his patient she was bleeding profusely and he
had considerable difficulty in removing this embryo and its
membranes. In so doing the ovum was ruptured, but it still

Fic. 6c—Section through the upper part of the vesicle, shown in Fig. b.
V, vesicle; C, cartilages at the tip of the spinal column, the last
being double.

retained a sufficient quantity of fluid to protect the embryo.
The time of the abortion was 77 days after the beginning of
the last menstrual period. The entire membrane and embryo

No. 1.] ORIGIN OF HUMAN MONSTERS. 143

were placed in 95 per cent alcohol one and one-half hours
after the abortion.

The above history makes it highly probable that the embryo
is normal, as does also its reconstruction. However, at the
tip of the tail there is a small vesicle which cannot be consid-
ered normal. It is lined with a single layer of cylindrical
cells, much like that of the central canal, is covered in part
with round cells identical with those of the cord, and has on
either side of it a spinal nerve, as shown in the diagram and
the drawings.

Fic. 6d.—Section through the vesicle, ’, nearer the tail with a ventral,
motor, nerve root on either side.

No. 10.

Embryo, C. R., 20 mm.

From Dr. W. S. Miller, Worcester, Mass.

At first I believed the embryo to be normal, but after it had
been cut into sections 20 microns thick, and the entire body
reconstructed from them, it was found that the abdominal
viscera were clumsy in shape and that the liver protruded into
the umbilical cord. A comparison of the picture of the re-
construction of the body of this embryo with those of both
older and younger specimens will show that the body of the
embryo is markedly distorted and that there is hernia of the
liver.

144 MALL. [Vor. XTX.

re,

Ss

Fic. 10.—Reconstruction of the embryo. X 8 times. L, liver; S, stomach;
W, Wolffian body; SC, suprarenal body.

No. 11.

Ovum, 10 x 7 mm.; umbilical vesicle, 1.5 x I mm.; “em-
bryo,” .8 mm.

From Dr. Kittridge, Nashua, N. H., March 16, 1893.

This specimen was sent me by mail in an ordinary 4-oz.
bottle filled completely with alcohol. Dr. Kittridge has pro-
cured for me the following history: “The woman, from whom
the specimen was obtained, is twenty-five years old, men-
struates regularly every four weeks, the periods lasting from

No. 1.] ORIGIN OF HUMAN MONSTERS. 145

Fic. 11a—Photograph of the entire ovum. Natural size.

four to five days. She gave birth to a child September 19,
1892, and had the first recurrence of menstruation December
19. The second period followed on January 25, and was very
profuse; it lasted until February 1. The next period should
have begun about February 22, but on account of its lapsing

Fic. 11b—Diagrammatic section of half the ovum with the embryonic
mass attached. XX 10 times. The villi are drawing only upon the
upper quarter of the chorion. Ec, ectoderm; en, entoderm; uv, um-
bilical vesicle; mes, mesodern; coe, ccelom; all, allantois; a, amnion.

the patient concluded that she was pregnant, and called at my
office a few days later. I did not examine her, but asked her
to remain quiet and await developments, as I thought possibly
that she might be pregnant. On the evening of March 1 she
fell and sprained herself, and during the same night had a

146 MALT [Vou XIX.

scanty flow. The flow recurred each day, and on the 7th of
March she passed the ovum. It was kept in a cool, moist
cloth for twenty hours, and when it came into my hands was
at once placed in a large quantity of 60 per cent alcohol.”

The ovum is very large for its age, having a long diameter
of 10 mm. and a short diameter of 7 mm. It is covered with
villi only around its greatest circumference, having two spots
without villi, as was the case with Reichert’s ovum. The
villi of the chorion are from 0.5 to 0.7 mm. long, are branched
and are somewhat fibrous in structure.

Upon opening the chorion it was found that the embryonic
vesicle is situated just opposite the edge of the zone of villi.

Fic. t1c.—Section through the umbilical vesicle and its invagination of
specimen. > 50 times. The three layers correspond with the ecto-
derm, mesoderm and entoderm. The invagination marks the cavity
of the amnion.

About it there is a considerable quantity of magma reticulé,
which I did not remove, and therefore could not obtain good
camera drawings. The portion of the chorion to which the
vesicle is attached was cut out and stained with alum cochineal
and cleared in oil, but even after this treatment it was impos-
sible to obtain any clear picture. The specimen was next
imbedded in paraffin and cut into sections 10 microns thick.
The series proved to be perfect. From the sections a recon-
struction was made in wax. .

The dimensions of the different portions of the vesicle are
as follows:

No. 1.] ORIGIN OF HUMAN MONSTERS. 147

Diameter of stem

$a ae eee a NSA 0.4. mm.
Wengthet Stent. a) ase wee eee OAs;
Lengtheofovesicle. va. soit aan ame is ear
Widthmotevesicle ;2 wt aaa sees 10 Speke
Lencile of invarination= 450.06 aa Oar:
Widihroteinvacination <¢ 2ifiess ae ee OnGig o+
Diameter of opening of invagination.... 0.03 “

The sections and reconstruction show that the embryonic
vesicle is attached to the chorion by means of a stem. The
greater part of the vesicle itself is composed of two layers.
ectoderm and mesoderm. In the neighborhood of the em-

Fic. 11d.—Section through the stem uniting the umbilical vesicle with
the chorion. X 50 times. The cavity within the stem lined with
epithelium is the allantois.

bryonic stem there is a third outer layer which shows all of
the characteristics of the ectoderm. Just beside the attach-
ment of the vesicle to the stem there is a sharp, deep and
narrow invagination of all three embryonic membranes.
Within the stem there is a sharply defined allantois which
communicates with the cavity of the vesicle just below the
cavity of the ectoderm. The ectodermal plate of the invagi-
nation is very broad but not of equal thickness throughout
its whole extent. It extends to the outside of the vesicle and
ends quite abruptly in the neighborhood of the stem. The
blood-vessels of the mesodermal layer extend to the stem but
do not enter it, nor are there any blood-vessels in the chorion.

10

148 MALL. [VoL. XIX.

Since the first publication of this specimen, embryos both
normal and pathological have been studied, all of which indi-
cate more and more that this specimen must belong to the
pathological class. The other pathological specimens in my
collection as well as the perfect normal specimen described
recently by Peters all speak for this conclusion. Yet the
presence of all three blastodermic membranes in it, with blood
islands in the mesoderm, and an allantois in the embryonic
stem, indicate that this specimen cannot be far from the
normal, but represents the earliest changes in the blastodermic
membranes in a specimen of the Peters’ stage under path-
ological conditions.

Fic. 12a—Photograph of the entire ovum. Natural size.

No. 12.

Ovum, 20 20.10m. embryo.cC oho 2s neni.

From Dr. Ellis, Elkton, Md.

“The patient from whom the ovum was obtained is twenty-
three years old, menstruated first in her fourteenth and mar-
ried in her twentieth year. Some time after her marriage
she became pregnant and aborted July 6, 1893, having passed
two periods at that time. The next time she became preg-
nant she aborted this specimen. She was last unwell Novem-
ber 7, the flow lasting five days, and she aborted on the 18th
of December, that is, I found the ovum in the discharges of
that day, although the waiting began the day before. The
patient says it has always been her habit to go more than
twenty-eight days, her periods recurring on the thirtieth day
usually, but frequently the intervals are longer, thus: She
was unwell on October 5 and on November 7 and in Sep-

No. 1.] ORIGIN OF HUMAN MONSTERS. 149

tember she went a week over her time. The patient is an
intelligent and truthful person and you can rely on her state-
ments.”’

The ovum appears to be perfect and normal, being covered
with the normal number of villi. The embryo within ap-
peared normal and of the two weeks’ stage. In reflecting
over the specimen, I have concluded that its brain is too small,

Fic. 12b.—Diagrammatic reconstruction of half the ovum with the embryo
attached. % 10 times. The villi are drawn upon the upper half of
the diagram only. Coe, ceelom; uv, umbilical vesicle; all, allantois;
mp, medullary plate.

the central canal too wide open, and the optic vesicles too
atrophic to be normal. The spinal cord is also too wide open
behind. The embryo could be viewed as normal with the ex-
ception of the spina bifida in the lower part of the cord and
the anencephaly in the anterior.

150 MALL. [Vor.ux Ux

1 Oo

Fic. 12c.—From a reconstruction in wax. X 40 times. Cs, eighth cervical
myotome; OV, optic vesicle; AV, auditory vesicle; H, heart; VOM,
yolk vein; P, ccelom; UV’, umbilical vesicle; Os, third occipital myo-
tome; All, allantois; Am, amnion. :

Fic. 12d.—View of the embryo to show the open spinal cord below and
the atrophic head with large neuropore.

No. 1.] ORIGIN OF HUMAN MONSTERS. 151

Sections of the chorion indicate also that it is practically
normal with the exception of some fibrinous masses between
the villi. Otherwise there is no indication of a change in the
structures of the villi nor in the syncytium.

It is certainly possible that all of these slight changes took
place during the twenty-four hours before the abortion, while
the uterus was making ready to expel the ovum.

No. 13.
Ovum, 8 x 7 mm.; vesicle within, I.4 x .85 mm.
From Professor His, Leipzig.
This embryo is the well-known specimen No. 44 of the His
collection. (See Anatomie mensch. Embryonen, IH, pp. 32
and 87.) The ovum is not completely covered with villi.

Fic. 13a.—Section through the umbilical vesicle and chorion of specimen
No. 13, His’s No. 44. Blood corpuscles are seen within the cavity
of the vesicle. > 30 times.

Within there is a small double vesicle which appears to be
the amnion lying upon the umbilical vesicle. Attached to the
denser (umbilical) vesicle there are numerous fibrils which
extend throughout the entire ccelom.

This specimen promised to be, at the time Professor His
described it, the valuable early stage sought for by all em-
bryologists, but unfortunately the sections prove it to be path-
ological. The great quantity of fibrils, magma _ reticulé,
within the coelom already indicated that the embryo is not
normal.

152 MALL. [Vou. XIX.

Fic. 13b.—Section through the amnion, jugular veins, umbilical vesicle
and chorion. XX 30 times.

Fic. 13¢.—Section through the umbilical vesicle as it joins the chorion.
x 30 times. The large irregular space in the chorion is a blood space
which communicates with the veins of the embryo.

Fic. 13d.—Embryonic vesicle ‘attached to the chorion. * 20 times. After
His.

No. 1.] ORIGIN OF HUMAN .MONSTERS. 153

The sections show that there is a double embryonic vesicle
composed of the amnion and umbilical vesicle, the walls of
which are thickened and fibrous, with the embryonic layers
but poorly defined. The tissues of the vesicle and its cavity
are well filled with migrating cells. The chorion is also
fibrous, with blood-vessels and migrating cells extending into
the villi. The syncytial layer is not extensive.

No. 14.
Chorion, 30 mm. in diameter; within them is a small double
vesicle with a short pedicle 1.5 mm. in diameter.
From Dr. Friedenwald, Baltimore, 1893.

Fics. 14a and 14b.—Sections through the nodule (vesicle) of the specimen.
25 times. A few blood islands as well as an enclosed mass of syn-
cytium are within the stem,

154 MALL. HL WAoiEs 2S.

The mesodermal layer of the chorion is thin and decidedly
fibrous with but few cells scattered through it. There are no
villi. There are groups of cells in the chorion, at the base
of the embryonic vesicle, which are probably islands of syn-
cytium inclosed within it.

The walls of the vesicle are thick and fibrous with no blood
island within them. It is covered with a single layer of
epithelial cells which have fallen off at points. Scattered
throughout the mesoderm there are numerous migrating cells.
At the base of the vesicles there are a few blood spaces with
blood cells within them. The vesicle is lined with a single
layer of epithelial cells.

At the base of the larger vesicle there is a large closed
space lined with spindle cells. A similar space lies imme-
diately below the smaller vesicle.

No. 20.
Chorion, 20: £46 mm:
From Dr. J. W. Williams, Baltimore, February 14, 1894.
From the exterior, the ovum appears to be normal with
well developed villi of the chorion. Within the ccelom, how-
ever, there is a great quantity of magma, within which were
buried several nodules. These were removed and sectioned.

Fic. 20a. Fic. 2ob.

Fic. 20a.—Exterior of ovum, showing long irregular villi. Natural size.
Fic. 20b.—Inside view of chorion, showing strands of magma reticulé.

Sections show that there is no amnion lining the chorion
and that the small nodules are only small masses of magma
which contain no cells. The villi are normal in form with
the usual quantity of syncytium upon them. At isolated
points between the villi there are small masses of a granular
substance which look like coagulated albumin.

No. 1.] ORIGIN OF HUMAN MONSTERS. 155

No. 21.
Chorion, I2 x 9 x 5 mm.; vesicle within, 5.5 x 3.5 mm.
From Dr. Cullen, London, Canada, January, 1896.
The fresh specimen, still inclosed within the decidua, was
hardened in a large quantity of formalin and sent by express
in the same fluid.

Fic, 21a.—Ovum covered with long irregular villi. Slightly enlarged.

From the external appearance, the ovum is apparently
normal, with well-developed villi branching a number of
times. Upon opening the specimen it was found that the
ceelom is filled with a small quantity of magma reticulé,
within which is embedded a very large transparent vesicle.

Fic. 21b.—Interior of chorion, showing magma and vesicle. > 5 times.

This, with its attachment to the chorion, was removed and
cut into serial sections 20 microns thick.

The main vesicle is brought in contact with the chorion by
means of a small secondary vesicle; both are inclosed with a
layer of mesoderm within which are numerous blood islands

156 MALL. [Vov. XIX.

The smaller vesicle is lined with a layer of large spindle-
shaped cells. Migrating cells are within the cavities of both
vesicles, and are also scattered throughout the surrounding
magma.

There are no blood-vessels in the chorion. The syncytial
layer is diminished, but is well formed upon the tips of the
villi. Here it often accumulates in layers, forming peculiar

strata.

Fic. 21c.—Section through the vesicle and chorion. X 25 times. The
second vesicle between the larger one and the chorion appears to
be the stem with a dilated allantois, although it is not attached to
the chorion.

No. 24.

Chorion, 21 x 16x 5 mm.

From Dr€, OO) Milles Baltimore.

The ovum was covered completely with villi which branch
a number of times. Upon opening the specimen it was found
that the coelom was filled completely with magma reticulé
of moderate density. No trace of an embryo could be found.
From time to time I made renewed search and finally decided
to cut the entire specimen into sections. After staining it
with cochineal a small nodule became visible when the speci-
men was placed in direct sunlight. This, with a piece of
chorion upon which it lay, was cut into serial sections 20
microns thick.

The walls of the vesicle are composed of three layers, the
outer being greatly thickened at points, but retains sharp

No 1.] ORIGIN OF HUMAN MONSTERS. 157

Fic. 24a.—Section through the vesicle attached to the chorion. X 25
times. There is a multiple allantois and multiple amnion with a
thick layer of epithelium over the vesicle.

Fic. 24c.—A still deeper section of the vesicle, showing the irregular
thickening of the ectoderm and entoderm.

158 MALL. [Vov. XIX.

borders. The mesoderm is hypertrophic. The inner layer
is irregular, thick and thin, with a tubular branching process
which extends to the stem of the vesicle. There are blood
islands in the vesicle and stalk, and the vessels extend to the
villi of the chorion. There are migrating cells in the tissue
of the pedicle.

The syncytial layer is very extensive, forming large buds
upon the chorion as well as upon the villi. At points these
buds coalesce to form islands, the centers of which are com-
posed of necrotic mass filled with fragmented nuclei.

No. 25.

Chorion, 25 mm. in diameter, with a pedicle within 6 mm.
long and 2 mm. in diameter.

Dr. J. W. Lord, Baltimore.

The ovum is covered entirely with long villi, and has a
hemorrhage on one side of it. The pedicle within has all of
the characteristics of the umbilical cord of an embryo five
weeks old. There is no trace of an embryo, but there are a

Fic. 25.—Section through the umbilical cord and amnion at their attach-
ment to the chorion. X Io times.

number of cells at the free end of the pedicle, which also has
a ragged edge. The amnion lines the entire ccelom and is
reflected over the pedicle just as it would be over the normal
cord.

Sections show that the club-shaped cylindrical body is in
fact the cord with its blood-vessels and amnion. The free
end of the cord is rich in round cells, appearing much like the
granulation tissue of healing wounds. At this point the end

No. 1.] ORIGIN OF HUMAN MONSTERS. 159

of the cord is infiltrated with cells, in addition to the nu-
cleated cells of the cord, and it has very ragged edges. It
appears as if the embryo had gradually fallen off, piece by
piece, leaving the ragged stump of a cord. The blood-vessels
of the cord are but sparsely filled with blood. At the base of
the cord there is a remnant of the umbilical duct. Apparently
the chorion is normal.

No. 29.

Chorion, 30 mm. in diameter.

Dr. W. D. Booker, Baltimore.

The ovum is covered with but few atrophic villi, and within
no trace of an embryo can be found. The ccelom is filled with
a cheesy mass or granular magma, like that usually found
within the amnion of pathological embryos. After the magnia
had been searched through most completely, the portions of
the chorion which might have a remnant of an embryo at-
tached were stained and cut into serial sections, but nothing
whatever could be found.

Sections of the chorion show that its walls and villi are
fibrous and thickened. There is no amnion present. The syn-
cytial layer is very extensive over the villi and chorion, in-
vading them at points. Immediately over the syncytium of
the villi, and occasionally between them, there is a gelatinous
envelope, which at times appears fibrinous. Within this en-
velope there are many leucocytes with fragmented nuclei.

No. 30.

Embryo, C. R., 60 mm.

From Dr. Snively, Waynesboro, Pa.

The woman from whom it was obtained is colored, and —
menstruated last from April 5 to 12. On June 19 she had
her first pains, which continued until the 21st, when the abor-
tion occurred, i. ¢., 77 days after the beginning of the last
period.

The specimen is apparently normal with the exception of a
hernia of the liver into the umbilical cord. The communica-

160 MALL. [Vov. XIX.

tion between the ccelom of the cord and the peritoneal cavity
is much too large for this stage and the liver protrudes into
the cord fully 5 mm.

No. 32.

Ovum, 30 mm. in diameter, within a pedicle 9 x 2 mm.
From Dr. W. D. Booker, Baltimore.
“Mrs. N., colored. Last menstruation began December 26,

~

1893, and lasted 4 days, the usual duration being from 4 to 5
days. Cohabitation with husband December 12 and January

Fic. 32a—Section through the cord and the amnion at its attachment to
the chorion. > Io times.

9. Hemorrhage began March 14 and continued until the
8th, when the abortion took place. The entire ovum was
placed in 80 per cent alcohol one hour after the abortion.”
The time between the beginning of the last period and the
abortion is 82 days.

Fic. 32b.—Section through the attachment of the umbilical cord to the
chorion. X 10 times.

No. 1.] ORIGIN OF HUMAN MONSTERS. 161

Upon opening the ovum I found within it a large pedicle,
g xX 2 mm., which had every appearance of the normal um-
bilical cord.of an embryo, 25 mm. long. The age of this
ovum when estimated by the menstrual history calls for a
cord of this size, but the chorion is undersized. At any rate,
we have a cord without an embryo. At the point at which
the cord should be attached to the body there is a mass of
- cells, making it appear as if the embryo ulcerated away. At
this point the blood-vessels are greatly distended with em-
bryo’s blood, which also permeates the surrounding tissues.
Within the cord there is a large space, the ccelom, as well
as a reticular space, as is shown in Figs 32a and b. The
mesoderm of the chorion and villi is fibrous.

No. 37.

Chorion, 25 x 18 x 15 mm., within a small nodule 2 mim.
in diameter.

From Dr. G. M. Gould, Philadelphia.

The entire ovum is covered with villi which appear normal
in form, both to the naked eye and under the microscope.

The specimen was macerated considerably, but the thick
sections I made of it are extremely instructive. The em-
bryonic mass within proved to be an atrophic cord, embryo

Fic. 37a.—Photograph of the entire ovum. Natural size.

and umbilical vesicle, as shown in Figs. 37b, c and d. The
cord with its blood-vessels passes directly over into the head
end of the embryo, which contains but a rudimentary nervous

162 MALL. [VoL. XIX.

Fic. 37b.—Section through the head, umbilical vesicle and chorion. The
pharynx and first aortic arches are cut across in the head. XX I0
times.

Fic. 37¢.—Section through the umbilical cord, vesicle and the chorion.
>< 10 times.

Fic. 37d.—Section through the attachment of the umbilical cord and
vesicle to the chorion. > Io times.

No. 1.] ORIGIN OF HUMAN MONSTERS. 163

system. The mesodermal tissues are characteristic and the
form of the pharynx and lower jaw is recognizable. From
this region the two branchial arteries pass into the cord, as
the figures show. A single vein, however, passes from the
cord directly into the center of the body and ends just below
the lower jaw. There is no heart, liver, myotomes, nor lower
end of the body, these being replaced by the cord. The ar-
teries are empty and the vein is distended with blood.

No. 54.

Embryo, C. R., 11 mm.

From Dr. McMorris, Belle Plaine, Iowa.

The embryo alone was given me. It shows an atrophic
head, but otherwise appears like a normal embryo of 4%
weeks.

In the sections it is seen that the central nervous system is
solid with the exception of the mid-brain, whose ventricle still
communicates with the exterior of the body through an open
neuropore. The head is atrophic. The vertebra are well
developed. The liver is large; the heart, other organs and
ceelom are difficult to outline.

No. 55.

Ovum, 35 x 20 x 14 mm.

From Dr. Watson, Baltimore.

Last period January 18 to 22, abortion March 13, 1894.
The specimen is a very solid fleshy mass, which contains a
sharply defined spherical cavity, 15 mm. in diameter, with
smooth walls. Absolutely no trace of an embryo found within
this cavity.

Blocks of the tissue were imbedded in celloidin and some
sections were cut. The sharply defined cavity proved to be
the ccelom, as its walls were formed by the chorion. The thick
fleshy mass proved to be villi of the chorion, syncytium, blood,
fibrin and pus. The walls of the chorion contain remnants of
blood-vessels, are partly invaded by leucocytes and are fibrous.
The main bulk of the villi and syncytium stains poorly and

11

164 MALL. [Vour. XIX.

appears necrotic. The mesoderm is fibrous, more or less
invaded by leucocytes and covered in part with a very active
syncytium. The cavity of the ccelom is partly filled with a
granular magma, in which are imbedded some cells.

No. 58.

Ovum, 20 x 18 x 12.

From Dr. Howard, Cleveland, Ohio.

“The specimen is from the first pregnancy of a woman who
has been married for one year. The duration of the men-
strual periods is usually from 3 to 4 days, the last one having
ended July 25. The August and September periods were
passed, and September 30 she had a hemorrhage which she
believed to be the usual menstruation; this ended October 1

Fic. 58a.—Photograph of the ovum with the piece to which the vesicle
is attached cut out and turned over.

with the abortion of the ovum. The time between the begin-
ning of the last period and the abortion is 71 days. Cohabi-
tation July 25 to August 5 and again on August 15, or sev-
, eral days before the first lapsed period.”

The ovum is only partly covered with villi and is filled with
a jelly-like mass of magma. Floating within this mass there

io: I] ORIGIN OF HUMAN MONSTERS. 165

is a large vesicle, 6 mm. in diameter, with transparent walls.

This vesicle in turn is partly filled with a granular deposit.
The syncytium is excessive. The mesoderm of chorion and

inclosed vesicle is very fibrous. There are blood islands and

<<

aay

VW 43

Sa

Fic. 58b.

Fic. 58c
Fic. 58b.—Sections through the vesicle at its attachment on the chorion.
X 10 times. Within the stem there is a sharply defined cavity lined
with epithelium and an hour-glass-like space filled with blood. On
one side the stem is covered with epithelium.
Fic. 58c.—The cavity of the stem, shown in Fig. 58b, enlarged 50 times.

a cavity lined with epithelium in the stem of the vesicle. The
main portion of the vesicle is composed of two layers, but
near the stem there are three layers present. The mesoderm
of the villi is hyaline and cedematous, and between them there
is a stringy mass of mucus or fibrin rich in leucocytes.

166 MALL. [Von. XIX.

No. 60.

Embryo, C. R., 8 mm.

Dr. Dobbin, Baltimore.

The body and extremities of the embryo appear normal in
form. The tissues are considerably macerated and may be
normal. The spinal cord is solid. There are large islands of
blood cells in the liver.

No. 69.

Ovum, 70'X 40° x 20) mums embiyonCe he 13:

Dr. Chabot, Baltimore.

The chorion is smooth, not being covered with villi. The
head of the embryo is atrophic and club-shaped and the body
is fairly plump. The arms are well developed, of the five-
weeks stage, and appear normal.

The central nervous system is distended and the brain is
macerated. The outline of the organs and of the peritoneal

Ftc. 69.—Photograph of the embryo attached to the chorion. Natural
size.

cavity is not distinct, and the entire body is filled with migrat-
ing cells. The main bundles of nerves are filled with spindle-
shaped cells, making them look like the nerves of amphibian
embryos. The epidermis is hypertrophied and at many points
forms papilla. The embryo end of the umbilical cord is
atrophic, invaded by migrating cells, and its blood-vessels are
greatly distended. The whole chorion and part of the cord
have undergone fibrous degeneration.

No. 1.] ORIGIN OF HUMAN MONSTERS. 167

No. 70.

Mole, 45 x 30 x 28.

Dr. Ellis, Elkton, Md.

“The specimen is from a woman whose periods were reg-
ular until July 28, 1896, when she passed her period. In
October she had a profuse hemorrhage, and on the 2oth,
aborted, the time between the beginning of the last period and
the abortion being 113 days.”

Fic. 70—Photograph of the cut surface of the mole. Reduced one-half.

The specimen, as the figure shows, is very solid, and sections
proved it to be composed of a mass of distended chorionic
villi, forming an hydatidiform mole. Between the villi there is
a large quantity of blood with an extensive syncytium which
forms a large solid mass on one side of the specimen. Within
the center of the specimen there is a small collapsed chorion
with poorly defined walls. The specimen was not cut into
serial sections, so it is impossible to state definitely whether
or not the embryo has been destroyed entirely.

No. 71.

Ovum; To: x Qo %°5 mm.

Dr. G. H. Whitcomb, Greenwich, N. Y.

Dr. Whitcomb writes me: ‘The specimen is from a woman
twenty-three years old who had been married three months
before the abortion occurred. She had been troubled with
chronic cystitis and endometritis but menstruated regularly.
After marriage she had two menstrual periods, but the third
failing to appear she concluded that she was pregnant. Seven
days after the lapsed period she slipped while descending the

168 MALL. [VoL. XIX.

stairs, and this was followed with some tenesmus. Four days
later I examined her and found a free flow of unstained mucus
from the uterus, with tenderness, hypereemia of the pelvic
organs and irregular pains. I requested a specimen of urine,
which was given me on the following day. It was found
loaded with pus and blood, and also contained the ovum.
Two days later the decidua was discharged. The specimen
was preserved in 50 per cent alcohol. Shortly after this the
woman became pregnant again, which went on to full term.”

The abortion from the above data took place 40 days after
the beginning of the last menstrual period. When the ovum
came into my hands, three years later, it was well preserved

>

Fic. 71.—Photograph of the ovum. Enlarged 2 diameters.

and had not been opened. The villi are well developed and
even, but slightly deficient on one side. I cut the specimen in
half around its greatest circumference and then stained the
two halves. Within there was a small amount of magma
reticulé and at the bottom of one of the shells of chorion there
was found a very small nodule. Otherwise there is nothing
within the ovum. The nodule was imbedded and cut into
sections 20 microns thick.

The syncytium and the chorion appear normal. There are
no blood-vessels. The nodule within the chorion is a solid
mass which appears in structure like dried red blood corpuscles
of the frog.

No. 77.
Ovum, 70 x 40 x 30 mim.
Dr. Horn, Baltimore.
The fresh specimen was sent to the laboratory and it was
immediately preserved in strong alcohol. After it was hard-

No. 1.] ORIGIN OF HUMAN MONSTERS. 169

B, blood;

Fic. 77b.—Section of one of the villi. Enlarged 160 times.
S, syncytium, small cells of which are scattered throughout the

mesoderm.

170 _ MALL. [Vov. XIX.

ened it was found to be of firm consistency and of a very red
color, indicating that it must be pathological. Later, when it
was cut in half, there was found within it a spherical cavity,
20 mim. in diameter, lined with a smooth, fibrous membrane
and filled with a clear fluid which permitted of a careful in-
spection of its interior. On one side of the cavity there was
a small elevation, one millimeter in diameter and one-fourth
of a millimeter high.

Sections were made of the walls of the specimen through
the elevation which proved to be a fibrous thickening of the
amnion at its junction with the chorion. There are no blood-
vessels in any portion of the chorion. Between the villi there
is a great quantity of syncytium, fresh blood and fragmented
leucocytes. At many points the syncytium and leucocytes
invade the chorion and the villi with the apparent intention
of destroying them. Where fresh blood and syncytium come
in contact there are many fragmented leucocytes present.

No. 78.

Ovum, 36 x 33 x 13 mm.; nodule within, 14.6 mm.

Dr. A. P. Stoner, Harlan, Iowa.

“The woman from whom the specimen was obtained men-
struated last on December 1, 1896, and the abortion took
place on February 26, 1897. The sac was perfectly smooth
when it was passed, and, without opening, it was placed in 50
per cent alcohol. After the abortion two or three pieces of

Fic. 78a.—Photograph of ovum with piece of chorion and nodule lying
on top of it. Natural size.

No. 1.] ORIGIN OF HUMAN MONSTERS. 171

Fic. 78b. Fic. 78c.

Fic. 78d.

Fics. 78b, 78c, and 78d.—The sections through the vesicle and chorion.
x 10 times. Blood is within the cavity of the vesicle. The stem is
partly covered with epithelium and there is a double amnion, shown
in Fig. 78b.

decidua and placenta were passed, weighing together about
30 grams, the right quantity, it seemed, for a ten-weeks ovum.
The woman’s husband has been absent for over ten weeks,
thus making the specimen at least that old. It appears as if
there had been an arrest of development of the embryo and
that the membranes continued to grow.”

When the specimen came into my hands the walls of the
chorion were perfectly smooth without any villi whatever. It
was filled with a clear fluid and within there is attached a
small double vesicle, measuring 1 x .6 mm. This was im-
bedded and cut into serial sections.

The chorion is atrophic and has no villi upon it. The
nodule within is covered with a single layer of epithelial cells
which becomes thickened over the pedicle. At one point the
thickening is greatly increased and immediately below it there
are two small vesicles lined with epithelial cells. The main
cavity of the vesicle is lined with a layer of cubical cells, and
is filled with a considerable quantity of round cells. This
cavity is hour-glass shaped and extends to the walls of the
chorion, as the figures show. The mesoderm of the vesicle

172 MALL. [Vor. XIX.

is increased in quantity and is filled with wandering cells. At
the base of the vesicle there are several blood spaces filled
with blood.

No. 79.

Ovum, 50 x 50 x 50 mm. >embrye, (Cri, 42 smite

Dr. Briggs, BlackvillesseG:

Dr. Briggs writes that the abortion took place 91 days after
the beginning of the last menstrual period.

The specimen came into my hands well hardened in strong
alcohol with all of the membranes intact. When opened it
was found that the inner walls of the amnion and the embryo
were entirely covered with a layer of firmly coagulated gran-
ular substance or granular magma.

Fic. 79—Photograph of ovum cut open, showing the embryo encrusted
in granular magma. Natural size.

The chorion is very hemorrhagic and thick on one side,
while on the other it is very thin. The sections show appar-
ently normal structures in the thick portion, while in the thin
portion there is an extensive leucocytic infiltration. At this
latter point the walls of the chorion are markedly changed,
being invaded by the syncytium as well as by leucocytes.

Serial sections of the embryo show that it must have been
strangulated before the abortion took place. The central

No. 1.] ORIGIN OF HUMAN MONSTERS. 173

nervous: system is greatly macerated, the liver has disinte-
grated and the aorta is greatly distended. The rest of the
embryo appears normal. The intestine is almost entirely
within the peritoneal cavity; a single loop of it still remains in
the opening communicating with the ccelom of the cord.

The embryo is completely covered with a layer of magma
which contains but few cells in it. Below this the épidermis
is wanting at many points, while at other points it appears
normal. At the edge of the epidermis there is every appear-
ance of an attempted regeneration, as its border is thickened
and has rounded and not ragged edges.

No. 80.

Oyun, 240% 18x16 mim; embryo, C. R.. 4 mn

Dr. Branham, Baltimore.

Embryo and ovum are apparently normal, with the excep-
tion of a mass attached to the ovum, which proved to be
diverticulum, its cavity communicating with the main ccelom.
The lower part of the embryo is bent upon itself. The whole
ovum had been preserved without opening it. Some magma
reticulé is within the ccelom.

Fic. 80a.—Photograph of the ovum and embryo. Enlarged twice. The
small additional mass forms a diverticulum of the ovum, the cavity
of which communicates with the exoccelom through a narrow open-
ing. The tail of the embryo is twisted.

174 MALL. [VoL. XIX.

Fic. 80b.—Section through the tips of the villi, including the surrounding
syncytium. S, syncytium; NS, necrotic syncytium; VY, villus. En-
larged 62 times.

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Fic. 80c.—Section showing the mucoid mass, M, rich in leucocytes and
containing a nest of syncytium, S. V, villus; Ch, chorion.

No. 1.] ORIGIN OF HUMAN MONSTERS. 175

As far as it is possible to determine, the sections indicate
that the embryo, cord and yolk sac are normal. The villi of
the chorion, however, which are well developed, have a con-
siderable quantity of a fibrinous mass between them which is
rich in leucocytes. The syncytium is well developed and at
the tips of a number of villi it is decidedly necrotic. It may
be that these changes are of sufficient importance to account
for the abortion.

No. 81.

Ovum, 65 x 55 x 35 mm; embryo, C. R., 15 mm.

Dr. Branham, Baltimore.

“The abortion took place just three months after the begin-
ning of the last menstrual period.”

The unopened ovum had been placed in a large quantity
of alcohol, and when it reached the laboratory I cut a window
into it to allow the alcohol to enter its cavity. Within an
embryo was found, which appears macerated and is broken

Fic. 81a—Photograph of the whole ovum. Slightly reduced.

in its middle. The crest of necrotic tissue on the head of the
embryo, the stumpy leg, the distended cord and atrophic
chorion, all indicate that it is pathological.

Two parts of the embryo were cut into serial sections and
different portions of the chorion were also examined.

176 MALL. [VoL. XIX.

Macroscopic as well as microscopic examination of the
chorion shows that it has undergone extensive degeneration.
Its walls are filled with large islands of blood and at points
there is leucocytic infiltration, showing that an inflammatory
process had also invaded it. Accompanying the inflammatory
process the syncytial layer of cells has invaded the walls of
the chorion, thus helping along its destruction. The meso-
derm of the chorion has undergone fibrous degeneration and
within its walls there are numerous cysts, some lined with flat
epithelial cells and some with cylindrical. The amnion ap-
pears normal and lines the entire ccelom.

Fic. 81b.—Photograph of the embryo within the chorion.

The embryo is somewhat atrophic. Its central nervous sys-
tem is macerated and there is a marked cyst-like dilatation at
the tip end of the spinal cord. All the tissues, including the
cartilages, show more or less dissociation. The necrotic crest
covering the top of the head gives all the appearance of an
ulcer; the ectoderm is destroyed and the mesoderm covering
the brain is greatly thickened and pigmented with round cell
infiltration of the surrounding tissue. The marked dilatation
in the cord encloses double cavities filled with a mucoid re-
ticulum, much as in embryo No. 32. This tissue is similar in
appearance to the normal notochord in amphibian embryos.

No. 1.] ORIGIN OF HUMAN MONSTERS. Ly,

No. 82.

Solid mole, 75 x 60 x 40 mm.

Dr. Cassidy, Baltimore.

“Last period began June 3, 1896, and this tumor was
passed March 8, 1897, about 40 weeks later.”

The specimen was brought to the laboratory fresh and was
hardened in formalin. It is pear-shaped, ulcerated on the
pointed end and the interior appears to be composed of fresh

blood clots.

Fic. 82a.—External surface of the mole, slightly reduced.

Sections of the large solid mass show that within it there
is a collapsed ovum with folds of the chorion extending
throughout the specimen. On one side of the specimen there
are long slender villi. Most of the layers of the collapsed
chorion are composed of double walls, usually in apposition
and occasionally completely blended. There is no amnion
lining the chorion. Along the main central body of the col-
lapsed chorion there are large quantities of fresh blood. The
rest of the tumor is composed of old blood clots and nests of
leucocytes and of syncytium. The syncytial nests are located
in great part along the chorion, show active growth when

178 MALL. [VoL. XIX.

Fic. 82b—Cut surface of the tumor, showing large masses of blood
between the distorted chorion. Reduced one-third.

they come in contact with fresh blood and are necrotic else-
where. At no point does the syncytium invade the walls of
the chorion.

It is impossible to interpret this specimen without admitting
that the chorion continued to grow after the ovum had col-
lapsed.

No. 87.

Ovum, 24 x 16'x OQ mm-yembryo;-C.R2,74 mam.

Dr. Cole, Peru, Iil.

“The last period took place April 15, 1896. On May 15
the woman had a slight flow which repeated itself every few
days until the 27th, when the abortion took place. The day
before the abortion the woman worked very hard.”

The lower end of the embryo looks atrophic and on the
opposite side of the ovum there is a vesicle 2.5 mm. in diam-
eter.

Both the embryo and vesicle with pieces of the adjacent
chorion were cut into serial sections.

The embryo proved to be a normal specimen about 21 days
old, with normal umbilical vesicle and so on. The vesicle on
the opposite side of the ccelom appears to be anything but an

No. 1.] ORIGIN OF HUMAN MONSTERS. 179

Fic. 87a.—Additional vesicle on the side of the ovum opposite the em-
bryo. Enlarged 2 times.

umbilical vesicle. It lies free in the cavity of the ccelom im-
bedded within the magma, and is in no way torn. It is com-
posed of three distinct layers: a thick middle layer, in which
are numerous blood islands, an epithelial lining layer, and an
outside layer, which does not completely cover the specimen.
On one side of the vesicle there is a sharp invagination of all
three layers, which projects well into the vesicle. The meso-
derm of this: invagination has also within it several blood
islands.

The chorion is normal in appearance, with blood-vessels
entering it from the normal embryo.

Fic. 87b. Fie. S7c;

Fics. 87b and 87c—Sections through the vesicle and chorion. X 25
times. The deeper portion of the invagination in Fig. 87b is shown
cut in cross-section in Fig. 87c. Blood islands may be seen in the
mesoderm.

12

180 MALL. [Vou. XIX.

No. 93.

Solid mass, 40 xX 20 mm.

Dr. Cassidy, Baltimore.

The specimen was sent to the laboratory fresh and was
hardened in formalin. Upon opening it, it was found that
within there is a cavity into which projected a large tongue of
fleshy tissue. Within this tongue there is a clot of blood as
well as a sharply defined cavity.

Sections, through different portions of the specimen,
showed that the outer sac is the decidua and that the tongue
of tissue is the chorion. Within the central cavity of the
tongue (ccelom) lies the amnion. I cannot state definitely
whether or not the remnants of an embryo were present, for
the specimen was not cut into serial sections. The walls of
the chorion are thickened and irregular, and around it are
packed hypertrophied villi with great quantities of syncytium
and blood between them. Covering the villi and syncytium
there is a layer of blood and fibrin separating them all from
the decidua. Within the mesodermal tissue of the chorionic
walls there are occasional islands of syneytium.

No. 94.

Ovum, 50 x 40 x 30 mm.; embryo, C. R., 20 mm.

Dr. Knill, Detroit, Mich.

Ovum is smooth with villi on one side of it only. The
amnion does not fill the chorion completely ; it measures 30 x
20 mm. Within the amnion there is much coagulated matter
which envelops the embryo completely. This granular magma
can be picked off easily in large flakes. The embryo thus ex-
posed is bent upon itself more than usual and appears mace-
rated, as if it had been dead for a number of days. The
features are not clear, the tips of the hands and feet not being
well defined. The lower part of the embryo is necrotic and
the spinal cord is protruding. The entire ovum has been
hardened in alcohol. |

The sections show that the villi of the chorion are some-
what atrophied, with occasional nests of leucocytes within

No. 1.] ORIGIN OF HUMAN MONSTERS. 181

Fic. 94.—Embryo partly imbedded in granular magma within the chorion.
Natural size.

them. The mesoderm of the chorion and amnion show clearly
marked fibrous degeneration. The embryo itself is normal
in shape, but the brain is greatly dissociated and the liver is
cloudy and projects into the cord.

All of the epidermis is exfoliated with great masses of
migrating cells lying between the embryo and the envelope
of magma.

No. 97.

Ovum, 32°5630 x 15 mm,;-embryo, C. Rip7;-A. R., 9 mm.

Dr. Goldman, Baltimore.

“Beginning of last menstrual period, March 8, 1897. Abor-
tion, May 8. The entire ovum was hardened in 95 per cent
alcohol.”

The ovum appears normal with the villi distributed equally
over it. Upon opening, it was found filled with dense magma
reticulé, in which could be discerned the faint outline of a
four-weeks embryo. A block of the chorion, including magma
and embryo, was cut into serial sections.

The form of the embryo, amnion and umbilical vesicle is
normal. On one side of the embryo the epidermis is wanting
and the amnion is filled with cells. The umbilical vesicle is

182 MALL. [Morsecexe

filled with migrating cells, but its blood islands and its ento-
derm appear normal. The chorion is fibrous. The outer
covering of the vesicle is composed of a short layer of col-
umnar epithelial cells. The magma of the ccelom is filled with
wandering cells.

Fic. 97.—External surface of the chorion. Natural size.

The nervous system is greatly dilated and dissociated. The
liver tissue is obscured and filled with migrating cells. The
contour of the abdominal viscera is obliterated and they are
likewise filled with migrating cells. Pharynx, heart, large
veins and aorta are greatly dilated.

No. 104.

Ovum, 35 x 35 x 15 mm.; embryo elongated, 12 mm. long.
If curled upon itself it would measure, C. R., about 7 mm.

Dr. J.-P West, Bellaires'Ohio:

“The beginning of the last menstrual period was on May
7, and the abortion took place on June 11, 1897. The entire
ovum was preserved in strong alcohol.”

The villi of the chorion appear atrophic, being wanting on
one side of the ovum. After the ovum was carefully cut in
half it was found filled with magma partly reticular and partly
granular. On one side is a snake-like embryo with straight-
ened head and atrophic extremities. The embryo, with a
piece of chorion to which it is attached, was cut into serial
sections.

No. 1.] ORIGIN OF HUMAN MONSTERS. 183

Fic. 104.—Photograph of the embryo within the chorion surrounded by
magma. Natural size.

The main walls of the chorion are fibrous. The amnion
is intact. The brain and spinal cord of the embryo are
dilated and dissociated,—probably macerated also. The out-
lines of the organs and body cavity are obliterated. The
boundaries of the liver can no longer be determined. The
tissues of the body are generally dissociated and they, with
the umbilical cord and magma, are infiltrated with migrating
cells. The heart, large veins and aorta are greatly distended
with blood. The head is atrophic.

No. 110.

Ovum, 46 x 30 x 30 mm.; embryo, C. R., 8 mm.

Dr. West, Bellaire, Ohio.

“The last period of the woman began September 22, 1897,
and lasted five days. On December 8 there was a slight flow
which continued until the 13th, when the abortion took place.
Hardened in alcohol.”

The shape of the ovum is oblong and its walls are fleshy,
the villi having all disappeared. Within there is a clear fluid
with a granular deposit covering the embryo. The embryo is
greatly macerated and is but slightly attached to the chorion.
At the point of attachment there is an elevated mound of
necrotic tissue, to which the embryo is stuck. There is no
distinct cord and the amnion is wanting. Evidently both
chorion and embryo have been dead for a long time.

184 MALL. [VoLt. XIX.

Fic. 110.—Photograph of the embryo within the chorion. Natural size.

The chorion is atrophic and the decidua is infiltrated with
leucocytes. The amnion, umbilical vesicle and the attach-
ment of the umbilical cord to the chorion are completely de-
stroyed. The embryo is atrophic, the face not being developed
at all. The central nervous system is swollen; the outlines
of the viscera and body cavity obliterated and filled with
migrating cells. The liver is small. The heart and large
blood-vessels are greatly distended.

No. 115.

Ovum, 30 x 27 x 22 mm.; amnion, Io x 5 x § mm.; embryo,
GOR.) 73 mm,

Dr. A. S. Atkinson, Baltimore.

The abortion took place two months after the beginning of
the last period. During the second month of pregnancy there
was continuous bleeding.

The ovum was brought to the laboratory fresh immediately
after the abortion and placed in strong formalin. It was
opened at once in formalin and found filled with a gelatinous,
transparent mass, which became fibrous after the formalin
had acted upon it. Later on alcohol made it opaque. The
chorion is practically free of villi and looks necrotic. The
embryo is well in the middle of the ovum and is apparently
separated from the chorion. The head as well as the tail is
atrophic.

Sections show that the villi of the chorion are atrophic,
with but a small quantity of syncytium attached to them. The

No. 1.] ORIGIN OF HUMAN MONSTERS. 185

entire chorion is surrounded with a mass of decidua filled with
leucocytes.

The magma of the ccelom is very dense and has within it
but few migrating cells. Within the greatly distended amnion
lies the embryo, looking much like a chick of the third day.
The peritoneal cavity communicates freely with the exoccelom,
in which hangs an atrophic umbilical vesicle. The lumen of the
umibilical vesicle is filled completely with entodermal cells, its

Fic. 115a—Embryo imbedded within the magna reticulé of the ccelom.
Natural size.

Fic. 115b.—Embryo attached to the chorion. 3 times.

blood spaces are greatly distended but nearly empty, and its
solid stem ends abruptly after it enters the body of the em-
bryo. There is no trace of either alimentary canal or liver
left. Rudimentary Wolffian bodies and ducts are present.
The central nervous system is solid. The heart and large
veins are simple in form and greatly distended with blood.

The mesodermal layer of the chorion and its villi appear
normal, with the exception of the tip ends of the villi, which
are enveloped in a mass of leucocytes,

186 MALL. [Vou. XIX.

No. 122.

Ovum, 20 x 16x 6 mm.; embryo, Cha s5 tum:

Dr. J. W. Williams, Baltimore.

“Last period began April 19, 1898, and the abortion took
place on June 23. Continuous bleeding for eight days before
the abortion.”

The transparent and fibrous chorion is covered with a few
scattered villi of irregular length. The embryo is atrophic
with a club head, large heart, stump tail and no limb buds.

Fics. 122a and b—Two halves of the ovum, showing ccelom and embryo.
xX 2 times.

The nervous system is greatly distended and dissociated.
The front of the head and the branchial arches are atrophic.
The liver is small, the Wolffian body well marked and the
body cavity sharply defined. The large veins of the body and
of the liver are greatly distended with blood, the aorta being
much enlarged and empty. The tissues of the entire embryo
are partly filled with loose round cells. The chorion is thin
and fibrous.

No. 123.

Ovum, 17 x 14 mm.; vesicle within, 1.8 x 1.5 x I mm.

Dr. H. J. Boldt, New York.

“The last menstrual period prior to the abortion occurred
August 14 or 15, 1898. Abortion, September 10. The whole
ovum was placed in 95 per cent alcohol within 10 minutes
after the abortion.”

No. 1.] ORIGIN OF HUMAN MONSTERS. 187

The entire ovum was covered with villi, apparently normal,
but surrounded by a layer of pus and blood. After opening
it I found the ccelom filled with a mass of coagulated fibrin-
ous albumin, the magma reticulé, within which no embryo
could be seen. ‘The two halves of the ovum were then stained,
which brought out prominently a small vesicle imbedded in
the magma. This vesicle had a rounded opening upon one
side (Fig. a), with a long pedicle upon the other, which ex-
tended towards but was not attached to a small mound on the
inside of the chorion. Vesicle and chorion were both cut into
serial sections.

The sections of the vesicle appear as those of the normal
umbilical vesicle. The opening on the side is undoubtedly
due to a tear, judging by its broken edges.

B (e

<p»

Fic. 123d.—Section through the vesicle. > 25 times. Entoderm, meso-
derm and blood islands are shown.

188 MALL. [VoL. XIX.

No. 124.

Ovum, go x 75 x 50 mm.; embryo, C. R., 35 mm. Abor-
tion 18 weeks after the beginning of the last menstrual period.

Dr. Cassidy, Baltimore.

The ovum was brought to the laboratory fresh and then
hardened in a strong solution of formalin. It appears as a
transparent cyst with a crescent-shaped placenta on one end,
measuring 60 x 50 mm. Upon opening it I found within a
second sac measuring 50 x 37 x 35 mm., which had tough

Fic. 124a—Whole ovum with placenta attached to one side of it.
Reduced one-half.

fibrous walls and proved to be the amnion. Within this was
the embryo, with club hands and feet, pointed ears and a very
thin, twisted, umbilical cord.

Sections of the placenta show that the villi are matted
together and are covered with a thick layer of decidua cells.
The entire thickness of villi is infiltrated with leucocytes,
which at points are accumulated sufficiently to form small

Fic. 124b—Ovum cut open, showing amnion. Reduced one-half.

T]

Fics.

ORIGIN OF HUMAN MONSTERS.

124c, d, e—Three views of the embryo.

Natural size.

190 MALL. [VoL. XIX.

Fic. 124f.—Section through the hand showing well-formed bone and cellu-
lar infiltration of the surrounding structure. Enlarged 17 times.

abscesses. The walls of the chorion are considerably thick-
ened immediately below the placenta and are fibrous in struc-
ture. Between the villi at their bases there is a quantity of
fresh blood, and between their distal ends there is a great
quantity of syncytium, which does not stain well and appears
to be necrotic. Masses of fine granules are seen which stain
intensely with hematoxylin, and on account of their uniform
size they are probably bacteria.

Fic. 124g.—Section through the foot with the phalanges numbered. En-
larged 17 diameters.

No. 1.] ORIGIN OF HUMAN MONSTERS. 191

Sections of this interesting specimen do not reveal very
much, for the tissues do not stain well. The form of the
organs and skeleton, with the exception of that of the extremi-
ties, appears to be normal. However, the skin appears more
fibrous than usual, being somewhat infiltrated with round
cells. In the deformed extremities this infiltration is very
pronounced and involves all of the structures of the hands
and feet with the exception of the cartilages, forming
syndactyly.

No. 128.

Ovum, 50° x 43 mm: embryo; C. IR: 20 mim.

Dr. Lupton, Baltimore.

The woman from whom this specimen was obtained is
eighteen years old and has one child. The first recurring
period after the birth of the child was on July 4, 1898; the
second period, August 5; and the abortion on October 20.

Fic. 128.—Embryo within the amnion and chorion covered with a delicate
mass of fibrils and granules. Natural size.

After the abortion the entire ovum was placed in water, and
18 hours later was brought to the laboratory. It was a beau-
tiful white specimen and I immediately placed it in formalin,
in which it was opened at once. The water did not seem to
have penetrated the ovum, as the embryo was not at all

192 MALL. [VoL. XIX.

swollen and appeared perfectly normal. The formalin, how-
ever, at once caused the coagulation of a delicate network of
fibrils which enveloped most of the embryo. The sections
show a delicate reticulum of fibrils within the amnion.

No. 130.

Ovum, 15 x 10 x 6 mm; vesicle within, 4 x 3 x I.5 mm.

Dr. De Saussure, Charleston, S. C.

“The specimen was passed by the patient while urinating,
14 days after the beginning of the last menstrual period. She
had no idea that she was pregnant and thought that the
specimen was a piece of mucous membrane from the bladder.
It was hardened entirely in 50 per cent alcohol.”

When the specimen came into my hands it was only half
covered with villi, the other half apparently having had them
stripped off. There was also a tear in the chorion through
which a vesicle was protruding. Upon lifting the ovum this
vesicle fell out. The ovum was then carefully cut open and

Fic. 130a—Ovum with extruded vesicle. Natural size.

was found to contain a considerable quantity of magma re-
ticulé. Within this there was a long pedicle, measuring 7 x 2
mm. There was also a space in the magma large enough to
hold the vesicle which had escaped. Both ovum and vesicle
were cut into serial sections.

The serial sections of the ovum show that the amnion is
still unbroken, as shown in Figs. b, c, d. Its greatest meas-

No. 1.] ORIGIN OF HUMAN MONSTERS. 193

Fic. 130b.—Section through the amnion, cord and remnant of the em-

bryo. X 10 times.

Fic. 130c.—Section through the amnion, cord and chorion. X 10 times.

Fic. 130d.—Section through the attachment of the amnion and cord to

the chorion. XX Io times.

194 MALL. [Vor. XIX.

urements are 10 x 4 mm., into which extends the umbilical
cord. At the end of the cord there is a mass of tissue mostly
broken down, the remains of the embryo. This mass is
ragged, without any form corresponding to an embryo, and
had the amnion been torn no doubt it would have fallen out.
The blood-vessels of the cord are gorged with nucleated blood
cells, but they do not extend into the embryo. The chorion is
normal in appearance.

The umbilical vesicle (Fig. 130a) is pear-shaped and com-
pletely closed. At no place is there a break to show its at-
tachment to the cord. Although considerably macerated, the
sections showed the characteristic structure of an umbilical
vesicle.

No. 132.

Ovum, 42 x 30 mm.; embryo, C. R., 15 mm.

Dr. Munson, Washington.

This specimen was kindly sent me by Dr. Lamb, who had
obtained it from Dr. Munson. The woman from whom it
was obtained menstruated last between August 15 and 20,
and aborted November 12. The embryo was preserved in a
50 per cent mixture of commercial formalin. The chorion is

Fic. 132.—Photograph of the embryo. Natural size.

atrophic with but few villi. The embryo has a stub head and
the extremities on the right side are atrophic, while those on
the left appear to be normal.

The organs of the embryo are about normal in form and
structure. The cord and brain are slightly dissociated. There
is a small number of migrating cells in the tissues of the
body as well as within the peritoneal cavity.

No. 1.] ORIGIN OF HUMAN MONSTERS. 195

No. 133.

Ovum, 32 mm. in diameter.

Dr. J. M. Hundley, Baltimore.

“Last period began September 15, 1898, and continued
eight days; bloody discharge began November 11th and abor-
tion occurred on the 19th. Both parents perfectly healthy.
Hardened in 75 per cent alcohol.”

When the specimen came into my hands I believed it to be
normal, but after cutting out a piece of chorion I found the
ccelom completely filled with a dense mass of magma reticulé.
In taking off the piece of chorion I cut the attachment of the
umbilical cord and thus located the embryo. The mass of
magma and a portion of the chorion encircling the embryo
were removed and cut into serial sections.

Fic. 133—Ovum with piece of chorion removed, showing dense magma
within. Natural size.

The villi of the chorion are fibrous but normal in shape,
with but litle syncytium at their tips. The syncytium imme-
diately over the walls of the chorion is greatly increased in
quantity. The ccelom is filled with magma and migrating
cells. The amnion is complete. Umbilical vesicle is filled
with desquamated entoderm cells. The embryo is distorted
and cramped; epidermis is exfoliated at the points where the
amnion contains masses of migrating cells; nervous system
distended and dissociated ; organs and peritoneal cavity fairly
well outlined ; liver filled with blood which forms large islands
at points; front end of head greatly distorted, eye macerated

and whole head gorged with round cells.
13

196 MALL. [Vor. XIX.

No. 134.

Ovum, 17 x Ir mm.; vesicle within, which is compressed,
measures in the sections 9 x 3 mm.

Dr. G;, N. Sominer, TrentcnyNa-

A number of the sections of this unique specimen were sent
me by Dr. G. N. Sommer, of Trenton, N. J., who also informs
me that the ovum had been passed with considerable pain
and hemorrhage by a young multipara, due to the introduction
of a bougie by the woman to produce abortion. The monthly
period had been five days overdue when the abortion occurred.
The bougie had been introduced several days earlier.

In stirring up the ovum the woman punctured it and it then
became filled with mother’s blood, which formed a clot around:
the embryo. The leucocytes invaded the walls of the ovum,
the stem of the vesicle and even the blood-vessels of the em-
bryo, and show all stages of fragmentation within the tissues
of the embryo.

The vesicle itself is most interesting, as it shows the effect
of an infraction upon a very young normal embryo. The

Fic. 134a.—Section through the ovum and embryonic vesicle. The um-
bilical vesicle is torn and collapsed. The invagination of its walls
and the myotome-like bodies are shown in Figs. b and c. B, blood
clot; L, leucocytes.

No. 1] ORIGIN OF HUMAN MONSTERS. 197

stem of the vesicle is quite extensive, in which are embryo
blood-vessels filled with blood. Many of them extend into the
chorion and some of them into villi. The walls of the vesicle
are composed of three distinct layers. The inner is com-
posed throughout of a single layer of sharply defined cubical
epithelium, the entoderm. Immediately next to this is an ex-
tensive mesoderm, which continues into the mesodermal layer
of the stem to the chorion. Near the attachment of the vesicle
to the chorion there is a sharp invagination of the vesicle
which is lined with a thick layer of epithelial cells, the ecto-

#e ig . * =
cy ee

Fic. 134b—Photograph of the invagination shown in dark in Fig. a.

derm. This layer lines only the invagination and does not
extend over the rest of the vesicle. Beyond and on the distal
side of the invagination the mesoderm is arranged in five
groups of cells which suggest in every way myotomes. In this
region there are embryonic blood-vessels filled with blood.
The syncytium is very extensive.

The blood clot from the mother within the ccelom is recent,
as is shown by the fact that there are present may red blood
corpuscles. In the periphery of the clot next to the chorion

198 MALL. [Vov. XIX.

the red corpuscles are partly broken down and appear as an
imperfect granular detritus, within which there is a network
of fibrin. There are as yet no pigmentary changes in the
tissues adjacent to the clot. The clot extends through a tear
in the chorion into the ccelom, and as this portion is ap-
proached it is noticed that its characters change. The red
blood corpuscles diminish in number, and the main coagulum
consists of leucocytes which extend through the surrounding
tissues. This mass of leucocytes also extends along the bor-

Fic. 134c.—Myotome-like bodies, three of which are shown in the col-
lapsed vesicle shown in Fig. a.

der of the red clot into the cavity and walls of the vesicle.
The blastoderm cells are intact on one side of the vesicle,
whereas on the other they have suffered desquamation and
have retracted from its walls. A part of the leucocytes com-
posing this part of the clot are in a very imperfect state of
preservation. They show great irregularities in the forms of
their nuclei and are in a state of fragmentation. Fragmented
leucocytes extend throughout the clot, a great portion of the
chorion and through the walls of the embryonic vesicle.

No. 1.] ORIGIN OF HUMAN MONSTERS. 199

The tissue elements of the embryo are for the most part well
preserved. There is no evidence of extensive necrosis. Occa-
sionally, where the clot of red and white corpuscles and fibrin
becomes clearly intermingled with the villi of the chorion the
syncytial cells stain imperfectly. The evidence of gross nec-
rosis is entirely wanting.

The blood-vessels of the chorion contain numerous leuco-
cytes, constituting in some instances what appears to be leuco-
cytic thrombi. One section was stained for bacteria, but none
were found.

The process as a whole is to be interpreted as an acute
hemorrhagic inflammation of the embryonic structures. The
large number of leucocytes undergoing fragmentation indi-
cates that the inflammatory irritant was of a severe nature,
and had acted with a considerable degree of intensity, as is
not only shown by the rich immigration of leucocytes, but the
severe retrogressive changes which they have undergone.

No. 135.

Ovum; 105 x 65x 65° mm-;, embryo, GC. R’, 9 mm.

Dr. Mosely, Baltimore.

The ovum was sent fresh to the laboratory and hardened in
strong formalin. It is fairly smooth, its walls being thin and
the villi are wanting. Upon opening it I found it filled com-
pletely with a gelatin-like mass which is neither fibrous nor
granular. Within this mass there is an atrophic embryo
standing upon a thin umbilical cord. The entire chorion is

Fic. 135a.—Embryo upon a mass of magma within the ccelom. One-half
natural size.

200 MALL. [VoL. XIX.

lined with the amnion. The head of the embryo is atrophic,
the body being shaped like a grain of wheat. The extremities
are more rudimentary on the right side than on the left.

The sections of the embryo show the cord distended, the
brain almost completely destroyed and the mesoderm of the
top of the head converted into a mass of mucoid tissue. The
head end of the chorda is greatly hypertrophied, being con-
verted into a mucoid tumor. On either side of this tumor
there are two large cartilages, normal in structure. Farther
headwards, buried deep in the mesoderm, there are two addt-
tional pearl-like bodies, which, on account of their appearance
as well as by their being encircled by an oval zone of pigmented

Fic. 135b, c, d—Three views of the embryo. Natural size.

cells, identifies them as the lenses of the eyes. These bodies
have within them lens fibers, making them look much like the
lenses of amphibians.

The front end of the head is necrotic. The heart is con-
voluted, its outline obscure and it is distended and filled with
a mass of blood cells. The outline of all of the abdominal
organs and of the peritoneal cavity can be determined,
although the tissues are considerably obscured by the great
quantity of round cells within them.

The entire wall of the chorion is very thin, and it is lined
throughout with a delicate amnion. The villi have all dis-
appeared and in their place there are islands of necrotic syn-
cytium covered with a hyaline layer of fibrin. The whole
chorion is infiltrated with leucocytes, which form small
abscesses at points.

No. 1] ORIGIN OF HUMAN MONSTERS. 201

No. 136.

Ovum, 14 x 6 mm.; embryo, C. R., 5 mm.

Dr. Campbell, Halifax, N. S.

“Beginning of last period August 21, 1898. Abortion Oc-
tober 16. Entire ovum was hardened in 95 per cent alcohol.”

The ovum is covered with rudimentary villi, and when
opened was found to be completely filled with magma re-
ticulé. Shining through this mass can be seen the embryo,
curled up, with extremities, myotomes, heart and umbilical
vesicle visible. This remarkable specimen is a four-weeks
embryo within a two-weeks ovum. The entire ovum with the
embryo was cut into serial sections.

Fic. 136a. Fic. 136b.

Fic. 136a.—Photograph of the ovum. Natural size.
Fic. 136b—lInterior of the ovum, showing faint outline of the embryo
buried in magma.

The villi of the chorion are atrophic and fibrous, with great
buds of syncytium hanging to them as well as to the main
wall of the chorion. Between the villi there is a small amount
of mucus or fibrin, within which there are numerous leuco-
cytes. Amnion, umbilical vesicle and embryo are apparently
normal and of the four-weeks stage. The embryo is twisted
on its long axis at about 90 degrees. The organs are normal.
The peritoneal cavity is normal in shape and filled with blood,
appearing as a fresh hemorrhage; the pericardial cavity is
empty.

No. 137.

Ovum, 65 x 50 x 30 mm; embryo, C. R., 16 mm.

Dr. Watson, Baltimore.

“Last period commenced September 26, 1808. Abortion,
December 21.”

202 MALL. [ VoL. DIEXe

The ovum is nearly covered with long and well-developed
villi, having a bare pole on one side. The ccelom contains no
magma. The embryo is broken from the cord and is macer-
ated on its ventral end. The head is atrophic; arms and legs
are normal. At the middle of the umbilical cord there is the
marked swelling seen in other specimens of this kind.

Sections of the chorion show the villi to be normal in form
but somewhat hyaline in structure and without blood-vessels.
There is a considerable quantity of syncytium. ‘The thick-
ened umbilical cord has within it a cavity partly filled with a
reticular substance, homogeneous in appearance, and more in-
tensely stained than the surrounding tissues. Within the cord
there are large blood-vessels, greatly distended with blood
cells, which extend through the walls into the surrounding
tissues.

Fic. 137——Photograph of embryo. Natural size.

Ten millimeters from the attachment of the cord to the
chorion is the umbilical vesicle. It measures 3 x 2 mm.;
its walls are all degenerated and its cells, which are necrotic,
fill its cavity. The stem of the umbilical vesicle reaches but
half way to the umbilical cord.

The central nervous system of the embryo is distended and
dissociated, the spinal cord being segmental to correspond
with the vertebree. The liver is necrotic and filled with blood.
The heart is collapsed and dissociated. The large blood-ves-
sels are collapsed and empty, while the small ones are filled
with blood. The outlines of abdominal organs are pretty
sharp, the tissues nearly normal in appearance and fairly free
from migrating cells.

Most of the epidermis has fallen off the embryo, but where
it remains intact it often shows irregular thickening.

No. 1.] ORIGIN OF HUMAN MONSTERS. 203

No. 141.

Ovum, 40 x 30 x 20 mm.; embryo, 8 mm.

Dr. West, Bellaire, Ohio.

“The specimen is from a woman, a mother of nine children,
who has always been healthy until about ten years ago.
From this time her health gradually became worse and worse.
She is extremely neurasthenic. Stomach is dilated, digestion
poor. Bladder irritable and urine scanty. Uterus large, thick
and retroverted ; leucorrhcea. The uterus is about three times
its normal size and has a number of cysts in the cervix. There
were several earlier abortions, the one before this, which took

Fic. 141—Piece of chorion with dense magma and misshapen embryo.
Slightly reduced.

place December 13, 1897 (No. 110), having been sent to you.
The last period began on October 27, 1808, and the abortion
followed on January 13.”

The chorion is fleshy, like No. 110, with but few villi, and
within the ccelom there is a great quantity of magma reticule
and a dissociated embryo about four weeks old.

The sections show that the chorion and villi are matted
together and contain but few blood-vessels. The syncytium
is very extensive, and where it is in large masses the most
central cells are necrotic. The mesoderm of the chorion is
fibrous and hypertrophic. There is a considerable quantity
of mucus or fibrin, rich in leucocytes, between the villi. This
condition may have been more extensive elsewhere, as only
the chorion in the neighborhood of the embryo was examined.

204 MALL. [Vot. XIX.

The great quantity of magma reticulé within the ccelom has
numerous migrating cells scattered through it.

The amnion is partly in contact with the chorion and at the
points of contact is normal in appearance. Where it is sepa-
rated from the chorion by the excessive quantity of magma
the walls of the amnion are greatly hypertrophied. The um-
bilical vesicle is collapsed and its walls have undergone hyaline
degeneration completely.

The central nervous system of the embryo is greatly dilated
and dissociated. The body cavity can barely be outlined. The
large blood-vessels are faintly marked by the blood within
them. The rest of the tissues are one homogeneous mass of
tissue cells infiltrated with round cells, within which can still
be recognized cartilages and nerve bundles. The boundaries
of the heart and liver are wholly obliterated, due to their dis-
sociation.

No. 142.

Ovum, 50 x 40 x 30 mm.; embryo, C. R., 15 mm.

Dr. Sommer, Trenton, N. J.

“Last period began September 28, 1898. On January 3
there were marked uterine pains; free hemorrhage February
1, and abortion February 4.”

The chorion is fleshy, with some villi. Within there is a
macerated embryo about five weeks old imbedded in a mass of
fibrin-like magma. Between the magma and walls of the
chorion there is a large space filled with clear fluid.

Serial sections of the embryo and chorion show most re-
markable changes. The chorion and amnion are greatly thick-
ened, are very fibrous and look in every respect like the mem-
branes in fleshy moles (No. 82, for instance). The villi are
matted together by a mixture of blood, fibrin and numerous
necrotic as well as living cells. The fibrinous mass within the
amnion is in all probability blood which has entered from the
exterior. It has all the appearance of blood clots found else-
where in the body, but in addition it has been invaded by wan-
dering cells from the embryo. The ccelom is partly filled

No- 1] ORIGIN OF HUMAN MONSTERS. 205

with a granular magma into which project numerous slender
villi arising from the walls of the thickened amnion.

The activity of the syncytial layer has been most pro-
nounced. At all points it invades blood clots and the meso-
dermal tissue of the walls of the chorion and the villi. Occa-
sionally it almost perforates the chorion to enter the ccelom.
At one point syncytial cells are within the ccelom, but the
serial sections do not extend far enough to show the point of
communication. More marked is a great area of active syn-
cytium within the amnion, surrounded with a clot of mother’s
blood. Not only does it spread as a double layer of cells to
the attachment of the umbilical cord to the chorion, but at

Fic. 142—Ovum with embryo. Natural size.

numerous points the nests of syncytium have nearly per-
forated the walls of the thickened amnion to enter the ccelom.
The whole picture reminds one much of cancer specimens.
The presence of the large blood clots within the amnion indi-
cates that the membrane must have been punctured, probably
by the activity of the syncytium, long before the abortion took
place. This, of course, would allow the syncytium to enter
the ccelom and amnion to there make its further attack, which
in turn may have caused the amnion to thicken and sprout so
much.

The embryo itself has also undergone most marked
changes. The dimensions of the ovum, the length and degree

206 MALL. [Vor. XIX.

of development of the embryo indicate that the pathological
changes began not later than the sixth week of pregnancy,
while the menstrual history of the mother indicates that at
least 14 weeks have elapsed between the conception and the
abortion. In other words, the pathological process has been
under way for at least eight weeks. The extreme changes
within the embryo also speak for this. The nervous system
is markedly dissociated and macerated. Arms and legs, ex-
ternal features, as well as most of the internal organs, have
vanished. ‘The liver is still marked, but is necrotic. Wander-
ing cells have invaded all of the tissues and are also beginning
to attack the cartilaginous bodies of the vertebra. Large
nests of them are also imbedded in the clots of blood which
surround the embryo. The main blood-vessels of the embryo
can still be traced through the surrounding tissues. The cord
is filled with embryo’s blood, but this is also necrotic.

From all appearances had this ovum remained in the uterus
much longer it would soon have become filled with mother’s
blood, which in turn would soon have solidified to make of
the specimen a typical fleshy mole.

Fic. 143.—Photograph of the vesicle. Natural size.

No. 143.

Large double sac, 15 x 10 mm., attached to the wall of the
chorion.

Dr. Stick, Glenville, Pa.

The chorion appears normal. The double cyst-like body
has thin walls and is filled with a clear fluid. The specimen
has been in strong alcohol for nearly twenty years.

Serial sections show a chorion, normal in appearance, to
which is attached the double vesicle as shown in the photo-

No. 1.] ORIGIN OF HUMAN MONSTERS. 207

graph. The structure of the walls of the two sacs is identical
with that of the mesoderm of the chorion with all of the
epithelial cells fallen off. ‘The two sacs do not communicate ;
the larger has smooth walls; the smaller has numerous small
vesicles, about 1 mm. in diameter, opening into it, and the
cluster of “air cells” are directly blended with the mesoderm
of the chorion. The specimen undoubtedly belongs to the
vesicular forms, peculiar only on account of its size.

No. 147.

Ovum, 30 x 27 x 20 mm.; vesicle, I mm. in diameter.

Dr. Pole, Baltimore.

“Last period began January I, 1899, and the specimen was
discharged March 23.”

The ovum is only in part covered with villi, the remaining
portion of the chorion being clear and transparent. The
ccelom is completely filled with magma which has turned very
white in the alcohol in which this specimen was preserved.

Fic. 147.—Interior of ovum. Slightly enlarged.

On one side of the ccelom, closely attached to the chorion,
there is a small vesicle and an irregular mass which may
represent the remnants of the embryo.

Sections of the chorion show that the mesoderm is very
fibrous and rich in cells. The vesicle within is about one milli-
meter in diameter and is located two millimeters from the
chorion, but not at all attached to it. Its walls are composed

208 MALL. [Vo.. XIX.

of only one layer of cells on one side of the vesicle, while on
the opposite side it has a second layer or mesoderm, .5 mm.
thick, in which are imbedded numerous blood-vessels filled
with blood. There are a few blood-vessels filled with blood
in the chorion in the immediate neighborhood of the vesicle.

No. 150.

Ovum, 35 x 30 x 10 mm.;-embryo, 5 mm.

Dr. Oertel, Augusta, Ga.

There are but few villi on the chorion. The embryo is
distorted and the arm on one side is unusually large.

The sections of the embryo show an extreme degree of
pathological change. The nervous system is swollen and
solid, and the contour of the viscera is wholly obliterated.
The large blood-vessels are greatly distended with blood.
Round cells are distributed equally throughout the body of
the embryo.

No. 152.

Ovum, .70 x 422 38m: -embryo~eG ke, 21 am

Dr. H. J. Boldt, New York.

“The specimen is from a woman suffering with endo-
metritis, this being her third successive abortion, which took
place in each instance during the third month of pregnancy.
The beginning of the last period preceding this abortion took
place on April 16; conception April 20 (?); and abortion
June 25, 180057

When the specimen came into my hands the chorion was
found to be smooth and apparently free from villi. The
cavity of the amnion is filled with a mass of granular magma
covering entirely an embryo over two months old. The um-
bilical cord is much twisted and thin, measuring .5 mm. in
diameter. The embryo was cut into serial sections and dif-
ferent portions of the chorion were also examined.

Microscopic examination shows that the chorion and am-
nion are fibrous. The villi of the chorion are matted together
with fibrin and a mass of cells, which have undergone hyaline

No. 1.] ORIGIN OF HUMAN MONSTERS. 209

degeneration. The stroma of the villi is very fibrous, being
invaded at many points by syncytial cells and leucocytes. At
numerous points there are large nests of leucocytes forming
abscesses. It is a plain case of the endometritis infecting the
chorion.

The embryo is imbedded in a large quantity of magma
giving every appearance of embryo No. 79 again. The or-
gans of the embryo are dissociated and macerated and the
tissues stain poorly, indicating that the embryo had died a
considerable time before the abortion took place. Again the
central nervous system is swollen and dissociated. Migrating
cells are found in clumps or scattered in all of the tissues. In
general, the connective tissues are more fibrous than normal,
the true skin showing considerable hypertrophy. The epi-
dermis is wanting.

No. 153.

Solid mass, 50 x 20 X 20 mm.

Dr. Stick, Glenville, Pa.

Last period began April 30; abortion, July 15, 1899.

The mass is pear-shaped and proves to be a ruptured chorion
partly inverted and imbedded in an organized clot of blood
and fibrin. The chorion is, of course, ruptured and at the
point of rupture there is a mass of blood, which forms the
large end of the pear-shaped mass. There is no amnion
within the chorion, nor could the embryo be found. A por-
tion of mucous membrane of the uterus is attached to the
chorion. The villi of the chorion are normal in form, but the
mesoderm of many of them have undergone a kind of coagu-
lation necrosis. The syncytial cells are generally normal in
appearance. There are many leucocytes throughout the tis-
sues, especially within the mesoderm of the inverted chorion.

No. 154.

Ovum, 10 x 7 x 7 mm., found within a mass of blood
within the uterine tube.
Dr. Boldt, New York.

210 MALL. [VoL. XIX.

The ovum was cut into serial sections, but no trace of an
embryo could be found. The sections show, however, that
the chorion had been torn, but the edges of the tear were
rounded and infiltrated with mesodermal cells. The main
wall of the mesoderm and the villi in the neighborhood of the
tear are fibrous and artophic. The rest of the villi are normal
in appearance.

No. 158.

Tubal pregnancy; vesicle, 2 mm. in diameter.

Professor W. T. Howard, Cleveland, Ohio.

The specimen came to me imbedded in celloidin and
mounted on blocks ready to cut. From each block sections
were cut, three of which proved to be through the chorion.
In one of these sections there was the remnant of an embryo
within the chorion; from this piece I removed the celloidin
and reimbedded it in paraffin and cut it into serial sections 50
microns thick.

The microscopical examination of the sections shows that
the chorion is denuded entirely of its villi, being in apposition
and apparently continuous with the wall of the uterine tube.
Occasionally the line of separation is marked by a row of
irregular cells, probably the remnants of the epithelial cover-
ing of the chorion. The mesodermic portion of the chorion
is somewhat fibrous, being smooth on its ccelom side and
without an adhering amnion. The nodule within is shriveled
and necrotic, only a few of its nuclei staining. It appears as
a double sac, together measuring 2 mm. in diameter, with a
clump of necrotic cells, appearing like those of the umbilical
cord, between them. In none of the sections is the embryonic
mass attached to the chorion. At one place, however, the
cord-like structure runs into a long process toward the chorion
with a blood-vessel (?) filled with blood in its center.

My interpretation of the embryonic mass is that it is com-
posed of amnion and umbilical vesicle of about equal size,
shriveled and partly torn into pieces, but still held together by
the remnants of the embryo and umbilical cord.

No. 1.] ORIGIN OF HUMAN MONSTERS. 211

No. 159.

Fragments of a chorion about as large as a walnut.

Dr. Golden, Elkins, W. Va.

“From a woman in good health who had aborted a year
before during the third month of pregnancy. During the
second month of the pregnancy, from which the present speci-
‘men was obtained, there was a slight flow of blood without
any pain. It continued for two days. Ten days later it re-
curred and continued for 24 hours. Three days later it re-
curred again, became profuse and the abortion followed. The
supposed duration of the pregnancy is ten weeks. No indication
whatever of endometritis. Both father and mother are per-
fectly healthy and are very anxious to have children.”

The specimen consists of portions of the mucous membrane
of the uterus, large portions of the chorion, amnion, but no
embryo is present. The mucous membrane is full of small
abscesses, and leucocytes have invaded all portions of the
chorion. The syncytium is very active, and at numerous
points the syncytium and leucocytes have invaded the meso-
derm of the chorion. The amnion is greatly curled up and
thickened. Its walls have undergone hyaline degeneration.
The cells covering the amnion on the side towards the ccelom
are generally proliferated, often forming islands.

No. 161.

Chorion, 50 x 25 x 25 mm.; embryo, Io mm.

Dr. Cassidy, Baltimore.

“Last period at the end of August. Abortion, November
17, 1899. After missing the next period patient took medi-
cine and had a rubber tube introduced into the uterus. Puru-
lent leucorrhcea during the past six months.”

The entire ovum was given me hardened in alcohol. It
was covered with hard clots of blood; on one side the villi
appear to be normal. Upon opening the ovum a mass meas-
uring I0 x 5 x 5 mm. was found attached to its walls, which,
after sectioning, proved to be a strangulated embryo. It was
imbedded and cut into serial sections.

14

212 MALL. [Vou. XIX.

The sections prove the mass to be an embryo of the fifth
week, filled and covered with round cells. These cells have
obliterated the structure of the head entirely, but as the tail
end of the body is approached the outline of the organs can
still be defined. The villi of the chorion are developed in a
great mass of blood and pus; the syncytium is excessive.
Within the stroma of the villi there are, at many points, many“
round cells which appear to be migrating cells from the
embryo.

No. 162.

Mole, 70 x 30 xX 30 mm.; embryo, I mm.

Dr. Wanstall, Baltimore.

The specimen came to me in formalin with the following
note from Dr. Wanstall: “Last period from September 2 to
7, that is her usual time, five days. The woman began bleed-
ing November 9, and passed the specimen on November 22.
She is the mother of five children and says that this is the

. ° . ad
Fic. 162—Section through the embryo. 15 times. Ch, chorion; am,
amnion; h, heart; wmb, umbilical vesicle; 7m, intestine; all, allantois
or possibly liver.

only time-she has aborted. There is not the slightest indica-
tion of uterine disease.”’

Within the specimen there is a cavity measuring 35 x 12 x
12 mm., lined with a smooth wall and filled with a jelly-like
substance, within which there is a very small embryo which
was cut into serial sections 50 microns thick. The sections
show a remarkable atrophy of the embryo and umbilical
vesicle. The chorion is very thin and is composed of meso-

No. 1.] ORIGIN OF HUMAN MONSTERS. 213

derm only. The villi and epithelial cells are wanting, but in
their place there is a thick layer of mother’s blood. The entire
chorion is lined with an amnion and into its cavity the nodule-
like embryo projects. Its tissues are not uniform, being thick-
ened at some points, necrotic at others, and mucoid at others.
Throughout the center of the nodule there are some capillaries
filled with blood. At the point of juncture between the amnion
and chorion there are three projections from the embryo into
the coelom—(1) the umbilical vescicle; (2) the allantois; and
(3) the heart. That the second is the allantois is indicated by
its cavity, which is multiple at points. The heart is within a
pocket of the ccelom and has an irregular lumen which is well
Alled with blood. At the base of the nodule there is a short
tube which communicates with the allantois, the intestine.

No. 166.

Ovum, 40 x 40 x 40 mm.; embryo, 2.5 mm.

Dr. Cassett, Baltimore.

Last period on October 18. On December 29 there was a
discharge of blood which continued until the 31st, when the
mole was expelled.

The mole is composed of very thick, fleshy walls within
which there is a cavity with a smooth wall, measuring 30 x

Fic. 166.—Section through the embryo. X 15 times. Ch, chorion; am,
amnion; 7, nervous system; 1, heart or umbilical vesicle.

214 MALL. [Vor. XTX.

20 x 20 mm. On one side there is a small atrophic embryo
2.5 mm. long.

The sections of the chorion show that its villi are. well
formed and are imbedded in a mass of blood from the mother.
Possibly the syncytial layer of epithelium is increased. The
coelom side of the chorion is smooth and is in contact with
the amnion. Attached to the amnion there is the embryonic
mass or remnant which does not reach to the chorion; there is
no umbilical vesicle to be found. The amnion and embryo
are completely separated from the chorion. There are no
blood-vessels in the chorion.

The embryo is cylindrical in form, being attached through-
out half of its length to the amnion and passing through it.
In the center of the embryo there is a solid column of cells
quite sharply defined—the remnants of the central nervous
system. At the tail end of the embryo there is a blind tube,
the allantois. The ccelom of the embryo, which is as a pocket
on its ventral side, contains an irregular sac which may be
either the heart or the umbilical vesicle; probably the former.

No. 174.

Ovum, 35 x 25 x 25 mm.; embryo, 13 mm. long.

Dr. Gibbs, Baltimore.

Last period January 11, 1900; bleeding five weeks later,
which continued until the eighth week, when the abortion fol-
lowed. The ovum is smooth, having but few villi, and is
filled with a granular magma.

Sections of the chorion show a marked degeneration of its
walls, nearly all of its villi having been destroyed. Those few

Fic. 174.—Embryo lying on piece of the chorion. Enlarged 2 diameters.

No. 1.] ORIGIN OF HUMAN MONSTERS. 215

fragments of villi which remain are imbedded in blood and
are riddled with the cells of the syncytial layer. The meso-
dermal layer of the chorion is no longer sharply defined and
is more or less filled with cells with fragmented nuclei, the
origin of which cannot be determined.

The embryo is of the stage of five or six weeks with pretty
sharply defined organs and tissues which are more or less dis-
sociated and infiltrated with wandering cells. Most of the
epidermis has fallen off; in the region of the olfactory pit
(which is almost obliterated) the epidermis forms two marked
horn-like elevations. The central nervous system is swollen
and dissociated more than the remaining tissues of the body,
the change being greater in the brain than in the cord. The
vascular system is gorged with blood which is beginning to
invade the surrounding tissues. This increase is most marked
in the umbilical cord, which appears cedematous.

No. 177.

Embryo, C. R., 12 mm.

Dr. Harrison, Baltimore.

The sections show well outlined all of the organs of an
embryo of the end of the fifth week, but they are dissociated
and swollen. So extensive is the dissociation in the head that
the brain has become practically solid, the vesicles being nearly
obliterated. The process is not so extensive in the spinal cord.
Most of the epidermis has fallen off.

The vascular system is again greatly distended with blood
which is infiltrating the tissues, especially those surrounding

Fic. 177—The photograph shows the rounded head and stubby leg. En-
larged 2 diameters.

216 MALL. [ Vo. XIX.

the larger arteries and veins. In general the tissues show the
changes always seen in embryos which have been gradually
strangulated before the abortion.

In this specimen there is one marked variation in the
changes usually found. The precartilage outlines all of the
vertebrae and ribs, but no true cartilage is as yet formed in
them. Back of the eyes in the occipital region there are on
either side of the head two cartilages well developed, much too
advanced for embryos of this stage. A more advanced stage
of this cartilage will be found in embryo No. 135. The head
is also beginning to become stumpy; the frontal process 1s
necrotic and is beginning to fall off.

No. 180.

Ovum, 20 x I5 x Io mm.; vesicle, 2 mm.

Dr. CW: Dodges Rochester (Nay:

“TI have in my possession a human embryo which, if I may
judge from some of your papers which I have seen, is likely
to be more valuable to you than to me, and for this reason
I have kept it intact, instead of sectioning it as I have been
sorely tempted to do. Its history is as follows: The woman
from whom it came is a patient of Dr. Edward Mott Moore,
Jr., of this city. On March 28, last, her right ovary was re-
moved. She left the hospital on April 15, and coitus occurred
May 13. On June 19 menstruation appeared and this ovum
was expelled, which was brought to me in a pill box (the
membranes being broken in handling), and put at once into
4 per cent formalin, in which solution it still remains. As
the dates given above are vouched for by the patient and the
physician, it seems to me that we have here an unusually
accurate and perfect history of the embryo, and, while it is
not so very young, its history may give it additional interest.”

Sections of the chorion show that its mesoderm is of nor-
mal thickness, but is fibrous and rich in nuclei. Throughout
the main wall of the chorion, but not in its villi, there are
numerous blood-vessels filled with blood, showing that at one
time an embryo may have existed.

No. 1.] ORIGIN OF HUMAN MONSTERS. 217

The villi are normal in form, with a very extensive syn-
cytial layer of cells over them. At points the syncytium
forms large islands, which can easily be seen with the naked
eye. Immediately over the vesicle within, an island of this
kind, a millimeter in diameter, arises from the main wall of
the chorion and sends processes up between the villi. The
mesoderm immediately below this island is thinner than the
rest, making it appear as if the violent growth of the syn-
cytium took everything before it, but that in the attempt to
produce new villi the fibrous mesoderm of the chorion would
not follow. At many points between the villi there is a slimy
mass of albumen well infiltrated with leucocytes and numerous
small islands of syncytium, some of which can be followed
back to their origin from the villi.

The vesicle within is composed of but one layer of cells,
those of the mesoderm with blood islands imbedded within it.
No trace of an entoderm can be made out, although the lumen
of the vesicle extends into a pedicle which, as a single strand
of cells, attaches itself to the chorion.

No. 181.

Ovum, 18 x 18 x 10 mm.

Dr. D. S. Lamb, Washington.

The ovum is filled with reticular and granular magma and
no remnants of an embryo could be found, although every par-
ticle which might contain it, with the adjoining chorion, was
cut into serial sections. The mesoderm of the chorion and
villi is edematous; the epithelial covering is poorly developed,
often being composed of but one layer of cells.

No. 182.

Head and upper end of the body of an embryo about five
weeks old.

Dr. D. S. Lamb, Washington.

Sections of this embryo show an extreme degree Bf dis-
integration of the embryo. The brain is converted into a
mass of cells filling the central canal entirely and extending
into the surrounding tissues of the embryo, the line of de-

218 MALL. [ Vor. XIX.

marcation being obliterated. The large veins of the body are
gorged with blood which also extends into the surrounding
mesoderm. On the frontal side of the head there is a straw-

Fic. 182.—Piece of head showing necrotic mass over the mid-brain.
Enlarged 2 diameters.

colored necrotic mass with some migrating cells within it. On
the dorsal side of the head the mesoderm is thin and blistered,
indicating the beginning of spina bifida. The cartilages alone
are still well defined.

No. 185.

Ovum, 40 x 25 %.15 mtn:

Dr. Sabin, Baltimore.

The abortion occurred seven weeks after the beginning of
the last period. The specimen was brought to me in formalin,
and upon opening it I found that the ccelom was stuffed with
reticular and granular magma. No trace of an embryo could
be found, although the entire ovum was cut into serial sections.

The main wall of the chorion is completely filled with leu-
cocytes from the mother and show all stages of fragmentation
of the nuclei. They form a fairly sharp border on the ccelom
side, making the chorion appear as the wall of an abscess.
The invasion of the chorion with leucocytés must have been
merely from the coelom side, as the villi are not invaded to
any extent. Some of the villi are cedematous, others atro-
phied, being covered with a normal amount of syncytial cells.

No. 188.

Ovum, 45 x 40:x.40umm, Fembryo,.C€ 7 17 aim.

Dr. G. N. Sommer, Trenton, N. J.

“Last menstruation began January 6; bleeding began
March 19, and ended in a few hours with the abortion. The

No. 1.] ORIGIN OF HUMAN MONSTERS. 219

unopened ovum was immediately placed in ninety-five per
cent alcohol.”

The ccelom is filled with granular magma, the chorion is
very fibrous, and the villi are mostly wanting. The tissue of
the mesoderm is very rich in nuclei, none of which appear
to belong to leucocytes from the mother. Three kinds can
easily be recognized—(1) those which normally belong to the
mesoderm; (2) blood cells from the embryo; and (3) an ex-
tensive invasion of the syncytial cells. This third group can
be traced directly from large mounds of syncytium lying upon
the chorion, from which they extend throughout the meso-
derm, frequently entering the larger blood-vessels. Often
large giant cells are seen, showing the usual characteristics
of the syncytium after it has invaded the mesoderm of the
chorion. ‘The villi are affected less than the main walls of the
chorion. No cells from the syncytial layer of the chorion
were found in any of the blood-vessels of either the embryo
or the umbilical cord. ;

The organs of this embryo are all normal in form and of
the proper degree of development for an embryo of this size.
The tissues are dissociated somewhat, the most marked being
that of the brain. The veins of the body are all gorged with
blood, with but little migration of blood cells into the sur-
rounding tissues.

.

No. 189.

Ovum, 28 x 25 x 15 mm.; embryo, 4 mm.

Dr Oertel, Avicusta, Ga:

The ovum, filled with granular and reticular magma and
contains a deformed embryo, lying within a distended amnion,
S mm. in diameter.

The umbilical vesicle and amnion appear to be normal for
an embryo of this size; the body, -however, is greatly de-
formed, the central nervous system being open throughout its
extent and encircles the dwarfed embryo like a broad hoop
around a ball. A number of the motor roots of the spinal
nerves are developed, more in the region of the tail than else-

220 MALL. [Vot. XIX.

where. There are no cranial nerves. The heart is a vesicle
filled with blood, hanging into the ccelom and slightly at-
tached to the body wall. Its vascular connection with the
body is cut off entirely. The blood-vessels of the body are

irregular in shape and entirely changed from the normal

Fic. 189a.—Photograph of the embryo. Enlarged 2 times.

Fic. 189b.—Section through the head of the embryo. 30 times. The
medullary plate, m, is open throughout its whole extent.

type. They are filled with blood which extends through their

walls into the surrounding tissues. The branchial arches cor-

respond to an embryo of this size. There are still traces of

optic vesicles, chorda and possibly allantois present, the liver

and stomach and intestine having degenerated.

No. 190.

Ovum, 25°x 22 x 12 7m.

Dr. C. M. Ellis, Elkton, Md.

The ovum is filled with reticular magma within which no
trace of an embryo can be found, although the entire specimen
was stained and cut into serial sections. The chorion and
villi are apparently normal, containing blood-vessels from the
embryo.

No. 1.] ORIGIN OF HUMAN MONSTERS. 221

No. 195.

Ovum, 30 x 30 x 30 mm.

Dr. D. S. Lamb, Washington.

No embryo could be found, although the entire ovum was
cut into sections. The specimen is well covered with villi
and contains some retictlar magma. The mesoderm of the
chorion and villi appears normal and is rich in blood-vessels
filled with embryo’s blood.

No. 196.

Tubal pregnancy; embryo, 2.5 mm. long.

Professor Brodel, Baltimore.

The specimen, hardened in formalin, contained two sus-
picious bodies which were both cut into serial sections. One
of these proved to be the embryo greatly deformed, repre-
senting a stage about three weeks old. The tissues of the
embryo are quite homogeneous, only the central nervous sys-
tem being recognizable. One eye and a large blood-vessel can

Fic. 196.—Tube cut open, showing the embryo. From a sketch by Pro-
fessor Brédel.

still be faintly outlined. At points the amnion and umbilical
vesicle are blended completely with the chorion.

The outside of the chorion has attached to it a few long
and thick villi which do not branch. The chorion and these
villi are covered with a layer of syncytium of unequal thick-

222 MALL. [VoL. XIX.

ness, which frequently invades the mesoderm. The whole
chorion is embedded in a large mass of mother’s blood.

The most remarkable part of this specimen is found within
the blood-vessels of the chorion. They are gorged with nu-
cleated blood corpuscles filled with a pigment of the same
color as that of the surrounding mother’s blood. It appears
as if the syncytium, in destroying the mesoderm of the chorion
and the mother’s blood, at the same time made it possible
for the blood of the embryo to take up the blood pigment
thus liberated. At any rate, the blood of a human embryo
three weeks old contains no pigment, and the sections of this
specimen permit of this interpretation. There is also a con-
siderable quantity of mother’s blood within the ovum around
the embryo, but as the specimen was opened before it was
hardened and the corpuscles are all perfect, they need not be
taken into consideration in the interpretation just given.

No. 198.

Ovum, 25 x 25 x 25 mm.

Dr. Larsen, Chicago.

The specimen came to me hardened in a mixture of bi-
chromate of potash and formalin. The interior is filled with
considerable reticular magma and large lumps of granular
magma. Imbedded in.this there is a large cylindrical pedicle
7 mm. long bent upon itself. Sections of this specimen show
that pedicle to be the umbilical cord rounded off at its former
juncture with the embryo.

Fic. 198.—Pedicle within chorion. Enlarged 2 diameters.

No. 1.] ORIGIN OF HUMAN MONSTERS. 223

The mesoderm of the cord, chorion and villi is fibrous,
having also an excess of spindle-shaped cells. The blood-
vessels are all very large, those of the villi as well as most of
those of the main wall being gorged with blood. The large
blood-vessels of the cord are empty. Within the cavity of
the amnion scattered throughout the magma there are numer-
ous flakes of tissue of the embryo and a great many free cells.

No. 200.

Ovum, 35 x 25 x 20 mm.; embryo, C. R., 14 mm.

Professor Brodel, Baltimore.

The central nervous system is dissociated and macerated
very much, the form of the brain and spinal cord being lost
entirely. The organs are all deformed, the liver in addition
being necrotic, as it does not stain at all. There is ulceration
of the front of the head, but over the rest of it, in spite of the
extensive internal change, the epidermis is intact.

The walls of the umbilical vesicle are broken down entirely
and its lumen is filled with a mass of necrotic cells. The
amnion, chorion, and villi are more fibrous than normal.

Fic. 200.—Broken embryo within piece of the chorion, showing stumpy
arm. Natural size.

No. 201.
Ovum, 80 x 60 x 50 mm.; embryo, C. R., 20 mm.
Professor Brodel, Baltimore.

The ovum was received without villi and upon opening it
it was found filled with a fluid which had hardened into a

224 MALL. [ Vor. > Gi D,%

jelly in formalin. The embryo is atrophic, with a necrotic
mass on top of its head.

The fleshy chorion proved when sectioned to be a mixture
of true chorion, villi, blood, fibrin, decidua, blood sinuses, pus
and syncytium. The layers are not at all in regular order, and
show all stages of disintegration. The mesoderm of the villi
is fibrous and is often invaded by leucocytes and syncytium.
At other points the syncytium invades the blood clot and fre-
quently maternal blood sinuses are filled with leucocytes and

syncytium.

HirGas2O nas

Photograph of the embryo. Enlarged 2 diameters.

Within the embryo most extensive changes have taken
place. The brain is greatly deformed and is severed, through
a growth of tissue, from the spinal cord in the region of the
medulla back of the deformed ear. In fact, the brain is in-
cluded within the cap-like body on top of the head. The
spinal cord begins quite abruptly in the upper cervical region
and ends in the same way in the upper lumbar region. At
its end there is a curious fibrous tumor measuring’ half the
diameter of the cord. The cord, so far as it is developed,
appears to be normal, but it is dissociated somewhat. Below
the upper lumbar region the spinal cord is wholly wanting,

No. 1.] ORIGIN OF HUMAN MONSTERS. 225

the spinal canal being filled up with mesodermal tissue rich
in blood-vessels. Where the cord is missing most of the
spinal nerves appear to remain, and many dorsal ganglia can
be made out. This all indicates that the changes in the cen-
tral nervous system took place after the spinal nerves were
developed from it.

Se

|

Se t
\ Sate

\
ea
SS
eae ae
% aS
ae /

Fic, 201b—Diagrammatic reconstruction of the embryo, showing the
extent of the central nervous system. 5 times.

The two eyes are united into a single one with a double
retina, two lenses, a single choroid, and a single optic nerve;
back of this it is double again. It certainly appears as if the
two eyes have wandered together and have united in the
middle line.

The epidermis is quite complete, being broken through at
the back of the head. The extensive ulcer which is found

226 MALL. [VoL. XIX.

Fic. 201c.—Section through the top of the double eye of the embryo.
30 times. The eyes are buried deep in the head, being covered with
mesoderm and epidermis.

here is very rich in blood-vessels, involves the walls of the
brain, but does not reach into its ventricle. At the highest
point of the head the epidermis has developed into a papilli-
form body; below this there is a large necrotic area in which
there is a great quantity of yellow pigment granules.

The mouth is closed, although the alimentary canal from
there to the stomach is open and appears normal. The intes-
tine is matted together, the cloaca and anus being obliterated.
The epithelium of the upper portion of the intestine shows
marked growths into this matted mass.

Fic. 201d.—Section through the optic nerve and double eye. XX 30 times.

No. 1.] ORIGIN OF HUMAN MONSTERS. 227

+,
EM

a”
os
ys

Fic. 201e.—Photograph through a section of the ear, showing the plug
which closes the external meatus entirely.

15

228 MALL. [Vo.. XIX.

The thoracic region, liver and vascular system have under-
gone practically no change. The extensive growth of meso-
dermal tissue throughout the embryo has caused an extensive
destruction and arrest of further development of the muscular
system. This is shown by all kinds of secondary changes in
the connective tissue, especially that of the skin, which 1s
markedly fibrous, as may be seen in Fig. 2o1e. Here the
change is so great that it obliterates the external auditory
canal entirely.

No. 204.

Ovum, I4 x 12 x 8 mm.

Dr. D. S. Lamb, Washington.

The specimen, said to be three weeks old, was found filled
with a mass of granular magma. The whole ovum was
stained and cut, but no trace of an embryo could be found.
The chorion and villi appear normal.

No. 205.

Ovum, 40 x x30 x 30 mm.; embryo, C. R., 6 mm.

Dr. D. S. Lamb, Washington.

“The specimen is about four weeks old and is from a
woman who had been married three months. Syphilis is
suspected in the case.”’

The chorion is partly encircled with the decidua, which is
more or less necrotic and well infiltrated with leucocytes,
showing that an inflammatory process was present in the
uterus. The chorion is fibrous at points and at others cedem-
atous, with but few blood-vessels present. The villi are
irregular and often very fibrous, being hypertrophied as well
as atrophied. Their outlines are irregular and they are cov-
ered with a dense and very irregular mass of syncytial cells.
But few of the villi have blood-vessels within them and they
are all empty.

The amnion is completely adherent to the chorion through-
out its extent, making these two membranes appear as one.
On the amnion side there are numerous fibrous tuberosities

No. 1.] ORIGIN OF HUMAN MONSTERS. 229

which appear much as small villi inverted. At other points
the epithelial covering of the amnion builds by itself a double
layer of cells, which often gives rise to papilliform processes
much like the syncytium on the outside. Sometimes this
layer of epithelium is raised, forming a blister with a fibrin-
like substance, possibly magma reticulé, throughout which
are scattered transparent round cells with very small nuclei.
The umbilical cord is quite fibrous, with large irregular
openings scattered throughout it. These are filled with a
mucoid substance in which a few nuclei are scattered. The
blood-vessels are all obliterated with the exception of the point
of the attachment of the cord to the embryo, where irregular
vessels are filled with blood.
The external form of the embryo is well preserved and is
covered entirely with epidermis which is much thickened. The
brain and spinal cord are swollen, the former being practically
solid in the region of the fore-brain. The heart and large ves-
sels are gorged with blood which extends from them into the
surrounding tissues, obliterating them almost entirely. Within
this mass of migrating cells can be seen the outlines of some
of the organs of an embryo about four weeks old. The liver,
stomach, and lungs are riddled, and but the faintest mark of
an endoccelom can be seen. It appears as if all the blood of
this specimen accumulated within the embryo, the cord and
the chorion being free, the extensive epidermis preventing the
migration of the blood cells into the amniotic cavity.

No. 207.

Ovum, 70 x 45 xX 45 mm.; twin embryos, 16 mm. long.

From Professor Brodel, Baltimore.

The specimen came to me unopened and hardened in a
strong solution of formalin. Its exterior is smooth with smail
villi at one of its poles. Within there are two embryos, both
macerated, with atrophic heads. The larger embryo meas-
ures C. R., 16 mm. The other is a little smaller, but as it is
broken, an exact measurement could not be made. The cords
of both embryos are atrophic.

230 MALL. [VoLt. XIX.

There is some granular magma within the amniotic cavity
with several large clumps in the coelom, where the two am-
nions meet:

Sections of the membranes show that the chorion is de-
nuded of most of its villi, with the exception of the point
over the atachment of the cord of the broken embryo. The
entire chorion is covered with its decidua, which is rich in
blood sinuses and infiltrated with leucocytes. But few rem-
nants of the syncytial layer of the chorion remain.

The whole embryo is still covered by epidermis excepting
on top of the head, at the tail end of the body, and at the
attachment of the umbilical cord. At these points there is a

Fic. 207a.—A whole ovum. Reduced.

marked destruction of the tissues, which are beginning to dis-
integrate. The top of the head is ulcerated, in front it is
necrotic and pigmented, as is frequently the case in other
embryos. The nervous system shows the usual changes seen .
in strangulated embryos. The vascular system of the embryo
is gorged with blood, but none is within the vessels of either
the cord or the chorion. Within the body there is quite an
extensive migration of blood cells into the tissues, obliterating
them in part, but the process of destruction is not so far
advanced as in No. 205. ‘The majority of the organs can be
still outlined. We have here a rapid infiltration with migrat-
ing cells of an embryo of forty days, with cytolysis rather
than dissociation of the tissues.

No. 1.] ORIGIN OF HUMAN MONSTERS. 231

The changes in the broken embryo are practically the same
as in the unbroken one, although they are more advanced.
Only the head, extremities and cord remain entire, and in

Fic. 207b—Photograph of the interior of the ovum, showing both em-
bryos. Natural size.

these the changes are more marked than in the corresponding
parts of the unbroken embryo. In the former it is practically
a mass of individual cells, while in the latter the brain is
swollen and quite solid.

No. 209.

Ovum, 20 x 15 x 10 mm.; embryo normal in form, about
two and one-half weeks old.

Dr Ge N.4j-sommer, Trenton, N. J.

“The woman from whom the specimen was obtained 1s
thirty years old. Three years ago she had a miscarriage
during the third month of pregnancy, and three months ago
she was delivered of a monster at the end of gestation. The
specimen was one of hydrocephalus and spina bifida with
hydramnios, fully eight liters of fluid coming away at the
time of delivery. She menstruated the first time yesterday
since her confinement, bleeding profusely all day, and in the
evening the ovum came away with a few blood clots. Within
the sac I could see the embryo, about 5 mm. long, attached
to the chorion by the cord.”

232 MALL. [Vor. XIX.

The specimen came to me in 95 per cent alcohol, and upon
opening it a large amount of magma was found within the
celom. Not finding the embryo, the whole specimen was
stained, imbedded in paraffin and cut into serial sections 50
microns thick. It happened that the embryo was cut into
coronal sections, and those containing the embryo with the
chorion attached to it were mounted.

The form of the structures of the embryo is normal,
only the tissue did not stain well, indicating that it had been
dead for some time before the abortion. Over the back and
tail of the embryo the amnion is closely adherent, but it is
wanting over the head. Here it ends abruptly, and this could
not be due to rough handling, for the embryo is well packed
with magma up against the chorion. Over the embryo the
chorion is very thin and without villi, which explains why the
embryo was seen in the fresh specimen. At some distance
from the embryo the chorion appears to be normal in struc-
ture.

No. 212.

Embryo, ©) 9.5, mane

Dr. West, Bellaire, Ohio.

The macerated embryo is from a large ovum which was
aborted October 9, 1902. Last menstrual period began on
April 3, 189 days before the abortion.

The tissues of the embryo show that its development was
arrested during the sixth week. The central nervous system
is completely dissociated, being but a mass of cells. The
other tissues of the body, except those of the head, have under-
gone no secondary changes. The face and the top of the
head have been converted into a thickened mass of necrotic
tissue, in which may be seen large veins filled with blood.
The eyes are immediately below the skin, thoroughly disso-
ciated, but the vesicular lenses can still be outlined.

No. 215.
Ovum, 45 x 40 x 40 mm.; embryo, C. R., 17 mm.
Dr. Unger, Mercersburg, Pa. Brodel Collection.

No. 1.] ORIGIN OF HUMAN MONSTERS. 233

Fic. 215.—Photograph of macerated embryo in a piece of the chorion.
Natural size.

The specimen is smooth and fleshy and filled with granular
magma, in which was found the remnants of a macerated
embryo. Sections of the chorion show that the decidua is
attached and that the amnion lines the whole ovum. The
chorion is well developed, but the villi are matted together;
it corresponds with its history, which states that the specimen
is about 12 weeks old. It was preserved in 10 per cent alcohol.

No. 223.
Mole, 40 x 18 x I5 mm.
Professor Brédel, Baltimore.
At the point of attachment to the uterus the “fibroid mass”

Fic. 223a——Photograph of the mole. Natural size.

234 MALL. [Vor. XTX.

is very rich in villi, which at its rounded end is composed
wholly of blood. The entire tumor is encapsulated with a
layer of pus. Between the villi the meshes are filled with

Fic. 223b—Diagram of the structure of the mole. B, blood and fibrin;
P, pus; S, syncytium; NS, necrotic syncytium; V, villi.

syncytium, which often give the picture of a cancer. Where
the syncytial cells are far removed from the blood they are
often necrotic.

No. 226.

Ovum, 60 x 60 x 30 mm.; embryo, C. R., 24 mm.

Dr. West, Bellaire, Ohio.

“The woman, mother of three children, menstruated last
on March 3 and aborted on May 29.” The ovum is covered
with a few large villi two mm. in diameter at their base, and
irregular clots of blood. Elsewhere it is smooth. The amnion
is filled with a granular mass, which was swept out easily
when opened. Between the amnion and chorion there is an
irregular mass of mother’s blood, which is partly organized,
showing that the chorion had ruptured some time before the
abortion took place. The tissues of the villi and the chorion
are somewhat fibrous, with very few degenerated blood-ves-

No. 1.] ORIGIN OF HUMAN MONSTERS. 235

sels within them, indicating that the circulation had ceased
some time before the abortion; which is confirmed by a study
of the embryo.

The external form of the embryo indicates that it was
nearly 50 days old when it died, for, with the exception of
the head, its form is practically normal. The menstrual his-
tory makes it 87 days, and if 28 is subtracted, ten days are
still left, which is time enough in which to bring on the
internal changes found within it.

In general the organs are sharply defined, but they do not
stain well; the cells appear as in coagulation necrosis. The

Fic. 226a.—Photograph of the embryo. Enlarged 2 diameters.

cartilages are also well formed, and the maxilla, mandible,
clavicle, humerus, ulna, radius, femur and tibia have begun
to ossify. All this indicates that this embryo died quite
suddenly and that the changes within it are to be viewed as
post-mortem changes.

The vascular system is well developed, the heart muscle
being normal in shape but very fibrillar; it does not stain
well. Most of the large vessels are empty and the blood
cells are scattered throughout the tissues of the ernbryo and
the cord. The muscle fibers are unusually well marked, and
the connective tissue seems to be thickened.

236 MALL. [VoL. XIX.

The most marked changes are seen in the head. Much of
the epidermis is still in place, but some of it has fallen off.
At the back of the head the destructive process has included
the back of the brain and the upper part of the spinal cord.
The fore-brain, mid-brain and the spinal cord of the trunk
are still intact and dissociated. The eyes are of normal shape
and position, but much macerated. The nerves of the head
can still be outlined, which shows quite conclusively that the
destruction of the medulla is of recent date.

Fic. 226b.—Reconstruction of the central nervous system of the embryo.

No. 228.
Ovum, 60 x 25 x 25 mm.; embryo, 4 mm.
Dr. West, Bellaire, Ohio.
“The specimen is from the first pregnancy of a fairly
healthy woman. Last period July 1 to 3, and the abortion
took place on October 10, 1903.”

No. 1.] ORIGIN OF HUMAN MONSTERS. 237

Fic. 228a.—Photograph of the ovum. Natural size.

The solid blood-red specimen contains a regular cavity,
30 x 18 x 18 mm., which is filled with a granular magma,
on one side of which is attached an embryo shaped like an
hour-glass.

Sections of the mole show that it is composed of thick
walls in which there is much blood, villi, a great deal of
decidua and some pus, especially on its outside. The meso-
derm of the villi and chorion is very fibrous and devoid of
blood-vessels.

Fic. 228b.—Diagrammatic section of the embryo. X 20 times.

238 MALL. [Vor. XIX.

The cavity of chorion is lined with a very thick amnion
and the remnant of an embryo indicates that its development
was arrested towards the end of the third week. The de-
forming process must have been active for at least 50 days.

The vascular system is still represented by a mass of cells
on the ventral side of the embryo, behind which there is a
large vessel full of blood extending towards the remnant of
the umbilical vesicle. No vessels extend to the chorion.

The central nervous system fills the main part of the em-
bryo, being much dilated in the head and pretty well filled with
round cells throughout. In front of the brain are two vesicles
which communicate with it through two long tubes. These
no doubt represent the eyes. In the neck there is a small
gland, possibly the thyroid.

No. 230.

Ovum; 75 x 60 x 5o mm. "embryo, ©. Ry 57 mm.

Dr. West, Bellaire, Ohio.

“The mother has had three children and three miscarriages.
She always menstruates regularly during her pregnancy, and
she has been undecided during the past seven months whether
or not she was pregnant.”

Upon opening the ovum it was found that the foetus is
greatly cramped and imbedded in much granular magma.
The cord is thin and knotted. The right leg has a club-foot
and the left has a dislocated knee-joint. Evidently the em-
bryo has been dead for a long time.

The tissues of the embryo and membranes appear normal;
they barely stain at all. The outer zones of the chorion are
slightly infiltrated with leucocytes.

The dislocated knee and the club-foot show that the car-
tilages are markedly deformed, but on account of the absence
of tissue reactions it must be concluded that this change took
place after the death of the embryo. The liver, brain, spinai
cord and eye are macerated, converted into a pulpy mass and
do not stain. All of the epidermis has fallen off. Appar-
ently the embryo died suddenly, for there are practically no
tissue reactions to suggest the contrary. 3

No.1] ORIGIN OF HUMAN MONSTERS. 239

FIG. 230a. Fic. 230b.

Fic. 230a.—Ovum cut open, showing embryo within imbedded in a mass
of granular magma. Reduced.

Fic. 230b—LEmbryo cleared of magma.

Fic. 230c.—Arms and legs of embryo. Two views of each are shown.

240 MALL. [VoL. XIX.

No. 232.
Ovum, 45 x 25 x 25 mm.; embryo, C. R:, 14 mm.
Professor Brodel, Baltimore.
Most of the chorion is devoid of villi except that imme-
diately over the attachment of the cord, which appears to be
normal. The villi of the chorion are somewhat fibrous, with

Fic. 232a.—Entire ovum with villi on one end. Natural size.

blood-vessels less numerous than usual, and are covered with
a rich layer of syncytial cells. The amnion reaches the
chorion.

The embryo is atrophic and is imbedded in a mass of
granular magma, in which there are numerous round cells.

Fic. 232b.—Embryo within the chorion.

No. 1.] ORIGIN OF HUMAN MONSTERS. 241

Most of the epidermis has fallen off. The head is cylindrical
in form, containing a solidified brain and dissociated eyes.
The lenses are composed of broken cells surrounded by a
very thick hyaline capsule. The organs of the body are not
sharply defined, being filled with many round cells. The
blood-vessels are mostly empty. Even the nerves and car-
tilages have lost their sharp borders. The extremities are
stubby, being composed of densely packed round cells which
show no differentiation.

No. 233.
Mole, 70 x 45 x 40 mm.
Dr. Miller, Hagerstown, Md. Brédel Collection.
The irregular mass appears as an ovum filled with blood.
Sections show, however, that there is a mixture without
rhyme or reason of all kinds of deformed villi, blood, syn-

Fic. 233.—External and cut surfaces of the mole. Natural size.

242 MALL. [Vov. XIX.

cytium, decidua and pus. No doubt at its attachment to the
uterus it received fresh blood into its center, while the leuco-
cytes attacked it on its exterior. Most of the villi are encir-
cled with fragmented leucocytes, which seem to have gained
the upper hand.

No. 243.

Ovum, 30 x 20 x 10 mm.

Professor Brodel, Baltimore.

The specimen is pear-shaped with smooth thin walls, over
which there are scattered a few thin villi. The whole speci-
men was cut into serial sections and no trace of an embryo
could be found.

Fic. 243.—External view of ovum. Enlarged 2 diameters.

No. 244.
Embryo, 4 mm. long.
From Dr. Kelly’s Sanatorium. Brodel Collection.
The specimen is enclosed in the amnion, which measures
25 x 15 X I5 mm. and is surrounded by a mass of granular
magma.

No. 1.] ORIGIN OF HUMAN MONSTERS. 243

Fic. 244a—Embryo, surrounded with granular magma, attached to the
amnion. XX 2 times.

Fic. 244b—Section through the head of the embryo. X 20 times.

one <

Fic. 244c.—Section through the body of the embryo. X 20 times.

16

244 MALL. [Vor. XIX.

The sections show that the amnion is attached along most
of the ventral side of the embryo, somewhat as it is in the
normal specimen at the end of the second week. ‘The central
nervous system is still quite sharply defined, being more char-
acteristic in the head than in the trunk. The heart is com-
posed of a solid mass of cells in front of the embryo, which
extends as a horn-like process to the head. Between the heart
and the body there is large group of epithelial cells, in which
there are scattered some small round cells, probably the rem-
nant of the liver. Otherwise the tissue of the embryo is of even
structure with an occasional necrotic area. The epidermis is
mostly wanting. There is neither umbilical cord nor um-
bilical vesicle present, the free embryo being attached to the
amnion only.

No. 246.

Ovum, 30 x 21 x 14 mm.; embryo, 3 mm.

Dr. Wegefarth, Baltimore. Brodel Collection.

Dr. Wegefarth writes: “The woman from whom this
specimen was obtained is the mother of two children, the
youngest about seven years of age. Since then she has had
five miscarriages, all of about the same age as this specimen.
No history of syphilis, but have started to give her iodide of
potash, with the hope that she may give birth to a child. I
shall be glad to have you turn the specimen over to Professor
Mall if it will be of any use to him. It would be interesting

Fic. 246a—Ovum with window cut out of it, showing dense magma and
embryo within.

No. 1.] ORIGIN OF HUMAN MONSTERS. 245

if the great fire we had recently could have played any part
in this trouble, as she felt well up to that time, and the fright
due to the fear that the fire would burn out her neighbor-
hood, too, kept her in a state of great excitement for about
24 hours.”

The external surface of the ovum is normal in appearance,
but when it was opened it was found to contain a deformed
embryo lying beside a very large amnion. Sections of the
chorion show that its structure is somewhat hyaline and the
villi are devoid of blood-vessels. ‘The embryo and membranes
were cut together and the sections show that the amnion is
greatly hypertrophied, folded and torn, and that the embryo

Fic. 246b.—Embryo covered with folds of the amnion. Io times.

is deformed and injured but lying outside of the amnion. The
heart and great blood-vessels are empty, the brain is distended
and partly filled with round cells; together they give the
appearance of an embryo of the beginning of the third week.
No liver can be found, but there are loops of intestine present,
as during the fourth week. ‘The otic vesicles are well defined,
but the optic vesicles are wanting.

No umbilical vesicle can be found, but this may have been
lost when the amnion was torn. The amnion, however, runs
down in a thickened ridge which contains two large blood-

246 MALL. [Vor. XIX.

vessels and an epithelial tube, the allantois, between them.
At no place is the amnion attached to the chorion, nor are
there indications that they have been torn apart.

No. 247.
Ovum, 40 x 40 x 17 mm.; vesicle, 2% mm.

yee,

Dr. Seymour, Trappe, Md. Brodel Collection.

The ovum was found filled with granular magma and in
the center of this, far away from the chorion, a free umbilical
vesicle was found. Sections of the chorion show that it is
nearly normal in structure without any signs of an amnion on
its inside. The villi are without capillaries. At points be-
tween the villi the syncytial cells form mounds below the
epithelium, which have a tendency to penetrate the mesoderm
of the chorion.

The pear-shaped body is probably the umbilical vesicle,
with a cavity lined with epithelium and a considerable amount
of mesoderm around it, in which there are numerous blood-
vessels filled with blood. There are some accessory vesicles
in this layer similar to those found in No. 78.

No. 250.

Ovum, Io x 9 x 9 mm.; embryo, 2 mm.

Dr. Sampson, Baltimore.

The specimen came imbedded in a mass of decidua, which
was obtained by scraping the uterus. When opened it was
found filled with magma reticulé, in which could be seen,
immediately beneath the chorion, a small embryo, and further
away, towards the center of the ccelom, the umbilical vesicle,
The whole ovum was cut into serial sections.

The chorion and villi are apparently normal in shape and
structure, being also very rich in blood-vessels which are filled
with embryo’s blood. The villi are bathed in mother’s blood
and covered with an active syncytium. The decidua is some-
what infiltrated with leucocytes, but there are no abscesses.

The front end of the amnion is torn and its free edge and
the embryo are imbedded in reticular magma, indicating that

No. 1.] ORIGIN OF HUMAN MONSTERS. 247

the injury took place before the abortion. The general shape
of the embryo and its degree of development are practically
normal. The heart is well formed and it, with the blood-
vessels, is filled with blood. The alimentary canal, brain,
spinal cord, otic and eye vesicles, myotomes and branchial
arches are much like embryo No. 12, which is practically a
normal embryo of the beginning of the second week. The
septum transversum is well marked and the thyroid gland is
just beginning.

Fic. 250a.—Ovum, opened to show the embryonic mass, within the
decidua. about 2 diameters.

Fic. 250b.—Section of embryo, encircled with magma, within the chorion.
The amnion is torn. XX 17 diameters.

248 MALL. [Vor. XIX.

Wn alin ee

ne,

Fic. 250c—Section of chorion, villi and decidua. There is a large
quantity of mucoid mass between the villi. > 17 diameters.

Fic. 250d.—Section through hind-brain, M, adjacent mesenchyme and
epithelial lining of pharynx P, to show cytolysis and dissociation
of the tissues. XX 250 times.

No: 1.] ORIGIN OF HUMAN MONSTERS. 249

The tissues of the embryo, however, and the cavity of the
front end of the brain are filled with numerous small round
cells wth fragmented nuclei. All stages of fragmentation are
seen, just as may be seen in the leucocytes in small abscesses.
Most of the red blood cells are within the blood-vessels, but
those within the tissues appear perfectly normal. On account
of the diminished number of mesoderm cells, in fact, they

<—

Fic. 250e.—The dotted area in the section shows the portion which is
enlarged in Fig. 250d.

diminish in proportion to the number of fragmented cells
present, the conclusion must be drawn that the latter arise
from the former. The epidermis covers the whole embryo.

The primary change in this specimen is no doubt in the
mesoderm, for all the rest of the embryo appears normal.
That the equilibrium was overthrown is indicated by the
necrotic amnion and the great amount of reticular magma in
the exoccelom.

No. 251.

Ovum, 30 x 25 x 25 mm.; embryo, C. R., 9g mm.

Dr. Ritter, Brooklyn.

Last period January 16, abortion April 3. Half of the
chorion is covered with villi and the other half is bare, thick-
ened and hemorrhagic. The amnion lines the entire chorion
and the cord is very thin. Sections show that the mesoderm
of the villi are rich in cells, fibrous and are devoid of blood-
vessels. The main wall of the chorion is apparently normal,
with a large number of vessels filled with blood scattered
through it. The decidua is very extensive, is hemorrhagic
and has a large number of abscesses in it. Apparently there
was an extensive endometritis.

250 MALL. [Vor. XIX.

Fic. 251a.—Embryo attached to the chorion. Enlarged nearly 2 diameters.

Fic. 251b.—Section of the embryo. > 8 times.

251

ORIGIN OF HUMAN MONSTERS.

No. 1.]

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MALL. [Vor. XIX.

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The head of the embryo is atrophic and is nearly filled with
a distended, dissociated and macerated brain. The eyes are
solid and the lenses have become dissociated, but they are
encircled with sharply defined and thickened hyaline capsules.
The brain is protruding behind the head. The heart and
blood-vessels are distended and filled with blood. The organs
and tissues of the body are not well defined, and are filled with
round cells. The epidermis is wanting. The extremities are
stubby, without structure and filled with round cells. The
cartilages are sharply defined, and the liver appears to be
about normal.

No. 252.
Embryo, 5 mm. long.
Dr. Lamb, Washington.
“First pregnancy in an unmarried woman twenty-three
years old. Patient missed a month, then had free hemor-

Fic. 252a.—Photograph of embryo, with amnion on one side and the
thickened chorion on the other. Natural size.

Fic. 252b—Section through the eye, small black spot in Fig. 2522.
X 20 times. sE, eve 732 sbram:

rhage which continued for a month, when the embryo was
expelled.” This would make its age three months, counting
from the last period.

No. 1.] ORIGIN OF HUMAN MONSTERS. 253

This remarkable specimen shows to what extent an embryo
may grow after its regular development has been arrested.
The specimen came to me attached to a solid body, as the
photograph shows, and it appears to be an embryo about three
weeks old. The free end of the embryo is bent upon itself
and runs to a point where two intensely black spots may
be seen.

Fic. 252c.—Section through the embryo at its attachment to the chorion.
x 20 times.

The membrane or body behind the embryo is undoubtedly
the amnion curled up, for it is covered with epithelium on the
side towards the embryo side, which continues over its body.
On the other side the mesoderm, which is thickened and
hyaline, is free, there being no border cells nor villi.

Fig. 252d.—Section through the embryo below its attachment to the chorion.
The body immediately beneath the epidermis is a solid lentoid struc-
ture.

The skin is markedly thickened, the epidermis sometimes
forming small papillae, or are sometimes buried, forming
pear-like bodies similar to those of epithelial cancer. Within

254 MALL. [Vor. XIX.

the body there is a large cavity filled with round cells. Near
the attachment to the amnion there are several such “‘abscess-
like’ masses within the embryo.

The pigment dots, on account of their position, undoubt-
edly represent the eyes of the embryo. Each forms a small
sac immediately below the skin filled with large free pigment
cells. Deeper within the “head” of the embryo a band of
pigment cells connects the two “eyes,” as may be the case if
we consider these cells as the connecting optic nerves.

No. 253.

~

Ovum, 35 x 30 X 15 mm.; embryo, 4 mm.

Professor Broédel, Baltimore.

Chorion and villi are somewhat hyaline, with indications of
blood-vessels within them. Ammnion, which measures Ig x

Fic. 253.—Embryo within the chorion. X 138 times. The collapsed bag
behind the embryo is the amnion.

13 X 13 mm.,, is attached at one point, has hyaline walls and
does not contain the embryo.

The embryo is a swollen infiltrated specimen of the third
week, with no brain and little of its spinal cord left. The

No. 1.] ORIGIN OF HUMAN MONSTERS. 255

rest of the structures (heart, ceelom and Wolffian body) are
quite sharply defined, but are all infiltrated with round cells.
Most of the epidermis is intact. The arm buds are well
defined.

No. 255.

Ovum, 20 x 20 x 10 mm.

Professor Brodel, Baltimore.

The villi are atrophic and fibrous. At points the syncytial
layer is well mixed with leucocytes, which also have invaded
some of the villi as well as the mesoderm of the chorion. The
whole chorion was cut into serial sections, but no trace of an
embryo was found. ‘There are no blood-vessels in the chorion,
nor were any remnants of the amnion found.

No. 257.
Ovum, 55 x 40 x 40 mm., with a pedicle within, 14 x 2
mm., to which is attached a body 4 x 0.5 mm.

Fic. 257.—Photograph of the specimen. > 1.5 times.

256 MALL. [Vor. XIX.

From Mr. Lankford, Baltimore.

A large portion of the chorion is covered with well formed
and apparently normal villi; a portion is hemorrhagic and
another is fibrous, appearing as though it had protruded
through the os. Sections through this portion show that the
villi are atrophic and have undergone fibrous degeneration.
The chorion is thickened and the decidua is infiltrated with
leucocytes.

The inside of the chorion is lined with epithelial cells, which
are continuous with those over the cord; it appears as if the
amnion had become completely blended with the chorion.

The cord is also fibrous, with some spots which have under-
gone mucoid degeneration. It contains three large blood-
vessels,—a vein and two arteries. The body at the end of
the cord is simply its continuation, with the umbilical vein
running throughout it lengthwise.

No. 261.

Chorion, 120 x 70 x 70 mm.; embryo, about 90 mm. long.
Dr. W. M. Lewis, Baltimore.

Fic. 261a.—External view of specimen. Three-fifths natural size.

No. 1.] ORIGIN OF HUMAN MONSTERS. 257

The ruptured and distorted foetus, which no doubt had been
dead for a long time, is imbedded in a mass of granular
magma.

Sections of the placenta show that the villi and chorion are
very fibrous and almost devoid of syncytium. The umbilical
cord is somewhat fibrous, with blood-vessels within filled with

Fic. 261b.—Fecetus within its membranes. - Reduced.

blood. The decidua contains large sinuses and is also well
filled with round cells.

The tissues of the hand and skin are somewhat infiltrated
with round cells, but other changes within them are not
marked. It appears as if the embryo died quite suddenly, and
therefore there are no marked tissue reactions.

No. 262.
Mole, 80 x 15 x I5 mm.
Dr. Giering, Baltimore.
The specimen was several days old when it came into my
hands and was then hardened in formalin. The interior is

258

MALL.

[VoL. XIX.

Fic. 262a,—Photograph of the mole. Natural size.

Fic. 262b.—Section of the embryo.

Enlarged about 10 times.

No. 1.] ORIGIN OF HUMAN MONSTERS. 259

filled with a large amount of granular magma, in which is
imbedded a necrotic embryo, 14 mm. long.

The decidua is filled with small abscesses, the leucocytes
invading the villi as well as the main walls of the chorion.
The changes in the embryo are extreme, the nervous system
being solid, filling up the stumpy head. The outlines of the
organs are hazy, they being filled more or less with round
cells. The embryo is falling into pieces; some of the ep1-
dermis is still intact.

No. 263d.

Ovum, 27 mm. in diameter; embryo, C. R., 15 mm.

Dr. Lyman, Baltimore.

The villi are apparently normal in form and in structure.
Possibly the mesoderm is a little fibrous. The blood-vessels
appear to be normal. ‘The cord is dilated, showing the double
enlargements, which are mucoid in structure.

The brain and spinal cord are dissociated, with the brain
protruding into the mouth, but the other organs are fairly

= Fic. 263d a—Embryo within the ovum. X 2 times.

260 MALL. [Vor. XIX.

well outlined. The heart and large blood-vessels are filled
with blood and there is some infiltration of the surrounding
tissues with round cells. The epidermis has fallen off. The
changes within the embryo may be due to maceration, but on

Fic. 263d b.—Sagittal section of the embryo. X 7 times. .

account of the sharply defined tissues of the chorion and slight
amount of fibrous changes in the villi and the mucoid dilata-
tions in the cord with some wandering cells in the tissues,
I am inclined to think that this specimen represents the earliest
stage of a strangulated embryo of the sixth week.

No.

1.] ORIGIN OF HUMAN MONSTERS. 261

Fic. 264.—Section of the vesicle attached to the chorion. X 15 times.

262 MALL. [Vo.. XIX.

No. 264.

Ovum, 25 x 20 x 15 mm., with a cavity within 10 mm. in
diameter.

Dr. Gardner, Baltimore.

“Last period occurred on August 12; abortion October 9;
but the menses had been irregular for three months before.”

The ccelom is filled with hard hyaline magma, rich in round
cells, in which is imbedded the umbilical vesicle measuring
21% mm. in diameter. The chorion is thickened and fibrous
and is covered with some villi, which are also fibrous. The
vesicle shows all the characteristics of the umbilical vesicle
and is attached to the chorion by a thick fibrous pedicle. At
the point of juncture it is rich in large blood-vessels filled with
blood. These radiate into the surrounding chorion, but do
not reach into the villi.

No. 268.

Embryo, ©. Rey 22mm:

Dr. Kammerer, New York.

The form of the embryo is normal, but its body is straighter
than usual. It was hardened in formalin and some of the
tissues are well preserved, but others, ¢. g., brain, liver, lungs
and muscles, are dissociated. The blood-vessels are filled with
blood and there are no wandering cells in the tissues. Compare
the form of this embryo with that of No. 256, Plate IIT,
Fig. 8.

No. 270.

Ovum, 40 x 30 x 30 mm.; embryo, C. R., 14 mm.

Dr. Wilson, Baltimore.

The chorion is only partly covered with villi, which are
atrophic and fibrous in structure, but contain some blood-
vessels in them. The main wall of the chorion is also fibrous
and of irregular thickness, with some blood-vessels in it. The
amnion has reached the chorion and is filled with granular
magma, which completely envelopes the embryo.

The central nervous system is distended, dissociated and
macerated. The large blood-vessels and heart are distended

(05 pt || ORIGIN OF HUMAN MONSTERS. 203

Fic. 268.—Photograph of the embryo. X 4 times.

FIG. 270a. Fic. 270b.

Fic. 270a.—Photograph of the ovum. Natural size.
Fic. 270b.—Embryo within the chorion, containing granular magma.
2 tines:

264 MALL. [Vor. XIX.

with blood and the tissues of the body are somewhat infil-
trated with round cells. The outlines of the organs are slightly
obscured, but some of the tissues of the body are sharpened
by the process of maceration, which does not seem to have
been of long duration.

Soe

Fic. 270c.—Sagittal section of the embryo. X 7% times.

No. 275.

Ovum, 40 x 30 x 25 mm.; embryo straightened and about
three weeks old.

Dr. Tobie, Portland, Me.

The chorion: of this specimen, thought to be two months
old, is thin and covered with some villi which are imbedded
in much blood. In structure it is fibrous, with a diminished
amount of syncytium upon it, and contains no blood-vessels.

Within there is a cavity, the amniotic, filled with a clear
fluid, into which the deformed embryo projects. The exo-

No. 1.] ORIGIN OF HUMAN MONSTERS. 205

ccelom is from two to three millimeters wide, and is filled with
typical magma reticule.

The structures of the embryo form almost a continuous
mass of tissue, in which the irregular central nervous system

Fic. 275a.—Photograph of the ovum. Natural size.

Fic. 275b.—Photograph of sections of the ovum, showing the embryo in
one of them. Natural size.

can still be outlined. Enough is left to show that the speci-
men began to become infiltrated towards the end of the third
week.

Most of the epidermis is still intact. The lenses of the
eyes form small pearls enclosed in capsules lying beneath the

266 MALL. [Vo. XIX.

Fic. 275c.—Section of the head-end of the embryo, amnion and chorion.
x 15 times.

skin. In front of them there are two small bodies connected
with the epidermis, which might pass for lenses, but are prob-
ably changed olfactory pits. Ina number of places the tissues
are fibrous.

No. 276.

Ovum, 70 x 35 x 35 mm.; embryo, 13.5 mm.

Dr. Stanley;-Portiand=Me.

Dr. Stanley writes that the time between the last menstrual
period and abortion is 80 days.

The walls of the chorion are partly infiltrated with blood
and on one side is closely adherent to a fleshy mass—the de-
cidua. Sections of these regions show that the decidua has
large blood sinuses and numerous small abscesses in it. The
villi of the chorion are imbedded in a mass of blood, are
covered with a normal amount of syncytium, but in structure
they are fibrous and devoid of blood-vessels. In addition,

No.

| ORIGIN OF HUMAN MONSTERS. 267

Fic. 276a.—Photograph of the ovum. Natural size.

Fic. 276b.—Interior of the ovum, showing broken embryo on one side
of it. Natural size.

268 MALL. [Vou. XIX.

they are invaded at numerous points by the syncytium, which
forms in them small vesicles, lined with two layers of cells,
and often filled with dense masses of small round cells. These
vesicles are very numerous and usually communicate with the

Fic. 276c.—Section of the embryo. 8% times.

surface of the villi by means of bands of epithelial cells. The
walls of the chorion are in apposition to those of the amnion,
but they are not invaded by syncytium.

The changes within the embryo are equally remarkable.
The spinal cord is dilated and dissociated; the medulla is

No. 1.] ORIGIN OF HUMAN MONSTERS. 269

solid, fills the entire head and protrudes from an opening
formed by the destruction of the forepart of the head. In
front of this opening the atrophic upper jaw may be seen,
containing nerves, and behind the epidermis has grown into
a small ridge, encircling the opening. What has taken place
in this embryo took place mechanically in No. 256 (see Plate
III): The outlines of the organs are not sharp, but those of
the precartilages are very definite. The blood-vessels are
greatly dilated and filled with blood cells, which make them
look like abscesses. They are especially well marked along
the line from the umbilical cord to the heart. In their imme-
diate neighborhood there is more or less infiltration with
round cells. The smaller veins and arteries are still filled
with blood.
No. 278.

Ovum, 6 x 4 mm.

Dr. Stanton, Albany, N. Y.

“This specimen was found accidentally in curettings from a
woman supposed to have chronic endometritis following preg-
nancy. There is nothing in the history by which the age of
the specimen could be estimated.” Part of the specimen had
been cut into sections before the specimen was sent with the
statement that no embryo had been found, it having fallen out.

I found that the half sent contained a ccelom, 3 x 2.5 mm.
filled with magma, in which there was a cavity about 1.5 x I
mm. Sections showed that the cavity was natural and not
sharply defined, without anything to indicate that an embryo
had been in it. On the contrary, it was found that the magma
reticulé was filled with a loose net-work of mesoderm cells,
which bound one side of the chorion with the other, as indi-
cated in the diagram which is from a reconstruction. These
cells are directly continuous with those of the mesoderm and
resemble them in every particular. At one point there is a
small group of epithelial cells, which may represent what was
originally the embryo.

Otherwise the chorion and its villi are normal in appear-
ance, being encapsulated in decidua which has in it some

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MALL.

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No. 1.] OKIGIN OF HUMAN MONSTERS. 271

Fic. 278b.—Outline of the main wall of the chorion, C, showing the
strands of mesoderm, M, that cross the ccelom, in which there is a
small epithelial mass, E, possibly the remains of the embryo. xX 18
times.

Fic. 278c.—High power drawing of the epithelial mass, strands of meso-
derm and chorion. > 50 times.

Fic. 278d.—The epithelial mass. X 500 times.

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[Voz XIX.

MALL.

272

No. 1.] ORIGIN OF HUMAN MONSTERS. 273

uterine glands. All in all, this specimen reminds one of
Peters’s ovum very much. ‘There are some leucocytes in the
decidua, but no accumulations of them, indicating inflamma-
tion of the uterus.

I consider this specimen one in which the embryo has been
destroyed, leaving a normal chorion without an embryo.

No. 279.

Fleshy chorion, 100 x 60 x 60 mm. Into the cavity the
umbilical cord, 30 x 5 mm., projects.

Dr. Kemp, Baltimore.

Part of the chorion is hemorrhagic; the rest appears nor-
mal. Sections show that the villi are nearly normal, with a
deficient amount of syncytium over them, even where they
are well imbedded in blood. Within there is an amnion, and
the worm-like process which proves to be the umbilical cord,
with its three blood-vessels. The vessels are well developed

Fic. 279.—Photograph of a section of the specimen showing the cavity
and cord within. Slightly reduced.

274 MALL. [Vor. XIX.

and fully one millimeter in diameter; there are also numerous
vessels in the villi of the chorion. The tissue of the chorion
is hyaline, with a diminished number of nuclei in it.

Undoubtedly the foetus escaped in some way shortly before
the abortion, the membranes and cord remaining some time,
long enough to undergo these changes. The blood-vessels of
the cord and chorion are empty, but well developed.

No. 280.
Mole) 40x25 3.25 0m:
Dr. Magness, Baltimore.
Within the mole, which is said to be five or six weeks old,

Fic. 280.—Photograph of the mole. 1% times.

there is an irregular cavity with smooth walls, measuring
10x 5x 5 mm. Sections were cut of the thick hemorrhagic
walls, which showed that the walls of the chorion are thin,
with considerable reticular magma attached to them on the
inside. No amnion was found. The villi are not very large,
are well developed, contain remnants of blood-vessels and are
covered with a mass of necrotic syncytium. The blood and
mucus over the syncytium is filled with leucocytes, which
invade the mesoderm of many of the villi. It is probable that
the whole ovum has been dead for several weeks, the embryo
and the amnion having been destroyed entirely.

No. 1.] ORIGIN OF HUMAN MONSTERS. 275

No. 285.

Ovum, 45 x 35 X 35 mm.; embryo, 8 mm.

Dr. Keown, Baltimore.

“Tast menstruation October 9 to 12; abortion December
20, 1904. The specimen came away unbroken, was washed in
water and placed in alcohol. There is reason to believe that
conception did not take place until the time for the period
which lapsed. The mother insists that this is the case, and,
‘nasmuch as all three of her children had diphtheria at that
time it is probably true.”

The chorion is mostly bare, with some hemorrhage in its
walls. The villi which are left are very fibrous, with but few
blood-vessels within them. The syncytium over them is very
active, and at numerous points it is heaped up in small]
mounds, which form depressions, making it appear as if they

Fic. 285a.—Photograph of the embryo and chorion. Natural size.

are about to invade the mesoderm of the villi as well as that
of the main wall of the chorion. The amnion fills the entire
chorion.

Between the villi there is a reticular arrangement of blood
and mucus, in which there are numerous leucocytes. The syn-
cytial bodies enter this reticular mass at numerous points and

make a very remarkable picture.
18

276 MALL. [Vor. XIX.

The embryo has an atrophic head and cord, showing, how-
ever, enough structures to fix its age at four weeks. The
spinal cord is dilated and dissociated and the brain is solidi-
fied, filling the entire head. The eyes are destroyed. The
blood-vessels are enormously distended with blood, which also
fills the tissues of the body, obscuring them to a great extent.
The epidermis is intact.

Fic. 285b.—Section of the embryo. X 13 times.

ORIGIN OF HUMAN MONSTERS.

1.]

No.

een them.

i with mucus betw

iG. 285c.—Photograph of vill

F

ecytes and

iG. 285d.—Section of a fibrous villus which is invaded by leuc

4

I

M. XX 250 times.

and mucus,

S,

adjacent syncytium,

278 MALL. [Vor. XIX.

No. 286.

Chorion, 100 x 50 x 40 mm.

Dr. Girdwood, Baltimore.

This remarkable specimen must have been dead in the
uterus for about five months, the last period having taken

lic. 286a—Photograph of the entire specimen. Natural size.

place during the latter part of May and the abortion on the
4th of the following January.

The chorion thickens as it passes into the large fleshy pla-
centa on one side and is very thin on the other. The thin

No. 1.] ORIGIN OF HUMAN MONSTERS. 279

twisted cord enters the chorion at the border of the placenta.
The embryo is well imbedded in granular magma.

Sections from the placenta at the point the cord enters it
show a most remarkable reaction. The amnion is folded upon
itself and has undergone hyaline degeneration. The chorion
is also hyaline and is infiltrated with leucocytes and syncytium.
The villi are fibrous, with numerous spots of hyaline matter
scattered through them. With them the lining cells of the
large blood-vessels show remarkable growth, forming small

Fic. 286b.—Photograph of the embryo. Natural size.

pearls of endothelial cells. They are also invaded by syncy-
tial cells at some points and at others by masses of leucocytes.

Between the villi there is a great mass of necrotic syncy-
tium mixed more or less with fresh blood. Throughout this
general mass numerous small islands of active syncytium may
be seen; there are also a great number of scattered leucocytes

Sections of the cord, abdominal viscera and hand show that
the embryo must have died quite suddenly, for there are no
tissue reactions seen in them. However, the tissues do not
stain well, the epidermis has fallen off and the large blood-
vessels are filled with blood containing the proper number of
leucocytes.

Fic. 286c.—Section of a villus. 62 times. V, villus; N, necrotic villi
and syncytium; H, hyaline degeneration of mesoderm and syncytium;
X, peculiar masses of cells in the mesoderm, probably degenerated
blood-vessels.

No. 288a.

Ovum, 85 x-3'5 x 35.mun: ; embryo, °C: se emm.

Dr. Brille, Baltimore.

On one end of the chorion there is a space (30 x 30 x 5 mm.)
filled with reticular magma. Within this, and pushed to one
side, a collapsed amnion may be seen, containing the embryo.

The entire mole is surrounded by decidua and pus, in which
there is the collapsed ovum. The intervening space is filled
with blood through which ramify a few long slender villi.
These are fibrous and devoid of blood-vessels. At points they
are invaded by syncytium and leucocytes.

The amnion, which is also fibrous, is partly filled with
magma reticulé and is very rich in degenerated migrating cells

No. 1.] ORIGIN OF HUMAN MONSTERS. 281

Fic. 288a b.—Photograph of sections of the mole, showing the embryo
pushed to one side. Natural size.

282 MALL. [VoLt. XIX.

from the embryo. The embryo is pushed to one side of the
chorion and is pretty well dissociated, but the tissues are
sharply enough defined to recognize that the embryo is not
over six weeks old. They are well infiltrated with round
cells which extend into the surrounding magma; there is no
epidermis present.

No. 289.
Embryo of the fourth week, 8 mm. long.
Dr. Brille, Baltimore.
The specimen is distorted and macerated and it is impos:
sible to determine definitely whether or not it is normal.

No. 290.
Mole, 50 x I5 x 10 mm.
Dr. Warren, Portland, Me.
The specimen is said to be from a six weeks’ gestation, and
the abortion is believed to have been induced by some emmen-
agogue. Sections were cut from different portions of this

Fic. 290.—Photograph of the mole. XX 2 times.

irregular mass and the remnants of a few villi were found,
which were more or less infiltrated with leucocytes. The bulk
of the mole is composed of decidua, mucous membrane of the
uterus, blood, fibrin and pus.

No. 1.] ORIGIN OF HUMAN MONSTERS. 283

No. 291.
Embryo, 5 mm,
Dr. Wegefarth, Baltimore. Brodel Collection.
The membranes are devoid of villi and very thin. The
umbilical vesicle is necrotic and filled with an irregular mass.

Fic. 291.—Embryo attached to the chorion. X 4 times.

Sagittal sections of the embryo show that the specimen is
pathological, its head being rounded and the epidermis having
fallen off. The spinal cord is distended and the brain is solid.
Veins and arteries are greatly distended with blood. Eye
vesicles are atrophic, and the lenses are dissociated, but encir-
cled by a sharply defined capsule.

No. 292a.

Ovum, 50 x 30 x 30 mm.; embryo, 3%4 mm.

Dr. West, Bellaire, Ohio.

“The ovum is from a woman thirty-one years old, who has
been married for ten years, but never had been pregnant before.
Last period November 10, and on December 24, after a hard
day’s work, she had a sudden gush of blood, and since then
has been wasting at times. The ova was expelled Feb-
ruary 4.”

284 MALL. [VoL. XIX.

The chorion is partly covered with long villi, which are
fibrous in some places and cedematous in others. The amnion
within, which fills the entire ovum, is partly filled with gran-
ular magma, through which can be seen the outlines of an
atrophic embryo. Sections of it show that the brain and

Fic. 292a a.—Photograph of ovum. Natural size.

Fic. 292a b.—Photograph of the embryo lying within the magma. X 7
times.

No. 1.] ORIGIN OF HUMAN MONSTERS. 285

most of the spinal cord have been destroyed; at one point the
cord ramifies through the embryo. In the middle of the em-
bryo the aortae and ccelom are sharply defined, but elsewhere
the tissues are entirely obscured by numerous round cells. The
epidermis is intact.

No. 293.

Embryo;.C. Re, 194mm.

Dr. Lamb, Washington.

Dr. Lamb writes: “Yesterday I sent you an embryo
aborted at the third or fourth month of pregnancy. I trust
that it may be of interest to you. It is from Dr. Munson, of
this city.

Fic. 293a.—A photograph of the embryo. X 4 times.

“T send it more particularly, however, to get some informa-
tion. I myself cut it out of the ovum, so that I know that its

286 MALL. [Vor. XIX.

lic. 293b.—Section through the swelling in the back of the embryo, show-
ing the blister of the epidermis. XX 12 times.

No. 1.] ORIGIN OF HUMAN MONSTERS. 287

condition was not caused by any rough handling. ‘The sac
contained some fluid in which were many flocculi, which no
doubt are the absent portions of the embryo. Along its spine
the embryo is whitish, but for the remainder was dark. Now
I do not understand that micro-organisms played any role in
this case to bring about the condition of the embryo, but it is
only a maceration produced by the surrounding fluid medium.
Still, I feel some doubt about my being correct, because I have
seen sO many cases in which there was no evidence of such
maceration. In fact, the condition of this embryo is rather
exceptional in my observation. Apparently the soft visceral
parts have first given way to whatever cause it was. Per-
haps to you this is a trivial matter, but I would like to know
what you think of it.”

Sections of the embryo show that all of the tissues are
normal in form and in structure, with the exception of a great
excess of round cells within them. Especially is this true on
the top of the head and along the back of the embryo. The
cedematous mass on the back is as a blister with the epidermis
lifted off. It is filled with a granular mass, within which
there are but few cells. All of the blood-vessels of the embryo
are distended with blood; there is also a great quantity of
blood within the pericardial cavity and some within the ven-
tricles of the brain. Possibly this condition accounts for the
excess of round cells in all of the tissues, but it cannot very
well account for the condition on top of the head and along
the back. Here there is a most decided infiltration of cells.

No. 295.

Foetus with pointed head.

Dr. Miller, Hagerstown, Md. Brodel Collection.

The vessels going to the vertex are much enlarged. The
scalp of the protruding vertex is very hemorrhagic, the blood
filling the subcutaneous tissue as well as that of the skin. The
embryonic hair follicles appear to be normal, but the epidermis

is also infiltrated with blood cells, and is crumbling off in
flakes.

288 MALL. [Vor. XIX.

Fic. 295a.—A photograph of the head. Natural size.

Fic. 295b.—Photograph of a section of the head. Natural size.

289

MONSTERS.

ORIGIN OF HUMAN

1.|

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290 MALL. [Vot. XIX.

No. 297.

Embryo, 6 mm. long.

Dr. Lamb, Washington.

This specimen was removed from the uterus with a curette
and is said to be nearly three months old. The distorted
embryo is of the three-weeks’ stage and shows extreme
changes in its organs and tissues. The chorion is thin and
atrophic. There is no trace of an umbilical cord, but instead
the embryo sits upon the amnion. The spinal cord is dilated
and the brain is fully dissociated, filling up the stumpy head
entirely. The blood-vessels are much dilated with blood and
all of the tissues are infiltrated with round cells which deform
the organs and obscure their outlines. The mandible is nec-
rotic and the distended medulla reaches almost to the mouth.

No. 298.

Tubal pregnancy.

Dr. Pearce, Albany, N. Y.

“T am sending you by this mail a Fallopian tube removed
at an operation on March 13. The tube shows rupture over
an hemorrhagic swelling. The clinical diagnosis is rupture
of ectopic pregnancy. It is from a young woman, aged
twenty-six, married, who states that the last menstruation was
three weeks before the operation. The surgeon is positive that
it is a case of ectopic pregnancy. I am not so sure of the diag-
nosis, but with the history given I thought it worth while to
send it to you, without close examination, etc.”’

I found two nodules, each about 10 x 6 mm., one hemor-
rhagic and the other with hemorrhagic walls with villus-like
bodies upon it. This second body has a lumen—the ccelom
(?). Neither of them contained any trace of an ovum. Then
the ends of the rupture were cut into serial sections, and in
one of them the remnants of the ovum were found. It is
about 4 mm. in diameter, composed of small fibrous villi
surrounded by an irregular syncytium, decidua and blood.
Some of the villi are invaded by leucocytes.

No. 1.] ORIGIN OF HUMAN MONSTERS. 291

Fic. 2908.—Section of the tube containing remnants of the chorion and villi.

19

292 MALL. [VoL. XIX.

No. 299.

Ovum; 16 x 12: x TOMI.

Dr. Burns, Memphis, Tenn.

The specimen, apparently normal, is filled with a mass of
dense magma reticulé. Serial sections failed to show even a
remnant of an embryo. ‘The structure of the chorion and
villi is normal, possibly a little cedematous. No blood-vessels
are present.

No. 302.

Ovum, 25 x 20 x I5 mm.; embryo, 4 mm.

Professor Brodel.

The ovum is apparently normal, being covered with irregu-
lar villi. Sections show, however, that the villi are fibrous,
with remnants of blood-vessels within them. The syncytium
is very active and is imbedded in a reticular mass of mucus
rich in leucocytes and pus.

Itc. 302.—Section of the embryo. XX 16 times.

No. 1.] ORIGIN OF HUMAN MONSTERS. 203

Within the chorion there is a vesicle (amniotic) one centi-
meter in diameter imbedded in much magma reticulé. This
in turn is filled with granular magma, in which there is an
embryo about 3% weeks old. The umbilical vesicle is de-
generated and lies in the reticular magma.

The blood-vessels and tissues of the embryo are gorged
with blood and the outlines of the organs are obliterated. The
brain is solid and the spinal cord is distended and dissociated.
The eye vesicle and lens are nearly destroyed. The umbilical
cord is very short and wide, without marked blood-vessels,
but it is infiltrated with round cells.

No. 304.
Ow, 5-5 X73 i,
Dr. Hunner. Brodel Collection.
The specimen is surrounded by some of the decidua and
much mucus, which is well infiltrated with leucocytes. The

Fic. 304a.—Photograph of half the ovum containing the embryo. > 4 times.

villi and chorion are apparently normal, with remnants -of
blood-vessels within them, and they are covered with an active
syncytium. The decidua is encircled with pus and fragments

204 MALL. [Vou. XIX.

Fic. 304b.—Section of the whole ovum encircled by the decidua. XX Io
times.

Fic. 304c—Section of the villi and surrounding tissue. XX 65 times.
D, decidua; S, syncytium; V7, villus; Ch, chorion; M, mucoid sub-
stance rich in leucocytes.

No. 1.] ORIGIN OF HUMAN MONSTERS. 205

of uterine mucous membrane, showing that an extensive in-
flammatory deposit cuts off the normal nutrition of the ovum.

The ovum is partly filled with magma reticulé, in which
there is imbedded an umbilical vesicle two millimeters in
diameter attached to the remnants of an embryo, without
myotomes. The neural canal is present and the body runs
out into a stem, containing a tube (allantois), which does
not attach itself to the chorion. There are also remnants of
an amnion present. All in all, the embryo appears to be
much like Graf Spee’s specimen, which is 1.54 mm. long.
There is no trace of a heart, but there are numerous blood
islands in the umbilical vesicle and there are remnants of
plood-vessels in the chorion, showing that the two were con-
nected at an earlier date.

No. 307.

Ovum, 40 mm. in diameter ; embryo, 20 mm. long.

Dr. Coe, New York.

The chorion and villi are imbedded in an hemorrhagic mass,
and the latter do not appear normal; they are often surrounded
by small. clumps of leucocytes, which invade the mesoderm
of the villi. The embryo was said to have been a beautiful
normal one, but it had been harshly treated and practically
ruined before it came to me. Sections of the embryo show
that the tissues are macerated and distorted and probably
normal.

No. 308.

Fetus, C. R., 84 mm.

Dr. Ballard, Baltimore.

“Without any previous bleeding, on February 28, 1905,
the fcetus as you have it was passed suddenly, accompanied by
the usual amount of hemorrhage. Probably one-half of the
placenta was retained, and was removed by curettement.
Patient is regular in menstruation, and previous to miscar-
riage menstruated November 19,:1904. She has one boy
who will be thirteen months old May 10, 1905, and another

206 MALL. [Vor. XIX.

Fic. 308.—Photograph of the foetus, showing the cord wrapped around
its arms, with a mass of granular magma in the amniotic cavity.
Natural size.

No. 1.] ORIGIN OF HUMAN MONSTERS. 207

son sixteen months older; no other children nor miscar-
riages.”

[The woman aborted again on November 27, 1905 (speci-
men No. 325), and the ovum proved to be decidedly path-
ological. On December 31, 1906, after being pregnant for
five months, she was taken with penumonia and aborted on
January 4. The placenta was strongly adherent and was
removed with difficulty. She died January 7, 1907. Appar-
ently this foetus was normal, but it was not sent to the labora-
tory. |

After the abortion Dr. Ballard found that the woman had
an interstitial fibroid, somewhat diffuse in shape, in the anterior
uterine wall. During some years she had some otorrhcea.
There is no reason to suspect that her husband has ever had
gonorrhoea or syphilis.

The specimen appears to be normal, but when I opened the
amnion, which had not been torn, I found it filled with a mass
of granular magma, some of which is shown in the illustra-
tion. The cord is well tied around the arms, indicating that
the fcetus had been doing some lively jumping. Sections of
the placenta, at the point the cord enters it, show that the
villi are fibrous (7?) and covered with-an active syncytium,
which is imbedded in bloody mucus containing large num-
bers of clumps of leucocytes with fragmented nuclei. The
tissues of the cord appear to be normal; the blood-vessels
contain but few blood cells.

No. 309.

Dr. Steensland, Syracuse, N. Y.

Ovum, 23 x 20 x 20 mm.; embryo, 4 mm.

The specimen, apparently normal, had been in alcohol for
three or four years, but has been well preserved. The amnion
filled the entire chorion, otherwise the interior also appeared
normal. Section showed, however, that the dilated amnion
was accompanied with marked changes in the embryo. All
of the tissues of the embryo are infiltrated with round cells,
obliterating, to a great extent, the organs and tissues. The

208 MALL. [Vor. XIX

Fic. 309a.—Photograph of the ovum. X 2 times.

.

Fic. 309b.—Interior of the chorion, showing the embryo. > 4 times.

No. 1.] ORIGIN OF HUMAN MONSTERS. 209

central nervous system is markedly dilated and filled with
round cells. In front the walls are broken and the round
cells are extended into the tissues of the front of the head.
The eye and ear vesicles are also dilated and filled with round
cells. No trace of a lens is seen, and the ear vesicle has two
sprouts on its ventral side. The whole epidermis is intact.

No. 310.

Ovum, 18x 14 xX 14 mm.

Dr. Watson, Baltimore.

The specimen is covered with villi which in sections proved
to be markedly changed. The mesoderm is hyaline, with
vacuoles in which there are free nuclei. The epithelial layer
is irregular and invades the wall of the chorion as well as

Fic. 310a.—Exterior of the ovum. X 2 times.

Fic. 310b.—Interior of a piece of the ovum, showing a large lump of
magma. XX 2 times.

[Vov. XIX.

MALL.

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No. 1.] ORIGIN OF HUMAN MONSTERS. 301

Fic. 310d.—Section of a villus. < 250 times. S, syncytium.

some of the villi. The villi are vacuolated, contain some
blood-vessels, and are covered with a fairly active syncytium.
Over this there is a mass of mucoid fibrin rich in leucocytes.
The interior of the ovum is filled with magma reticulé, and
contains no trace of an embryo nor amnion.

No. 311.

Ovum, 36 x 30 x 30 mm.; embryo, Gakero 5 mati:

Dr. Watson, Baltimore.

The walls of the chorion are thin and covered with a few
scattered and irregular villi. Sections show them to be in
all stages of degeneration, the large ones with blood-vessels
and a rich syncytium, and the small ones, which are fibrous,
devoid of syncytium and infiltrated with leucocytes. The
spaces between the villi have a considerable amount of blood
between them, and where this comes in contact with an active
syncytium the nuclei of the leucocytes are fragmented; else-
where they are not. Portions of the main wall of the chorion
are very thin, fibrous and devoid of an epithelial covering.
Throughout the amnion is in contact with the chorion and is
often blended with it. .

Within the amniotic cavity there 1s a mass of granular
magma which could be seen through the thin walls of the
chorion before it was opened.

Fic.

MALL. [Vou. XIX.

Fic. 311a.—Ovum covered with ragged villi. >< 1% times.

311b.—Interior of ovum with embryo imbedded in granular magma.

No. 1.]

ORIGIN OF HUMAN MONSTERS.

Fic, 311Ic.—Section of

Fic. 311d.—Sagittal section through the middle line.

< 6 times.

303

< 6 times.

304 MALL. [VoL. XIX.

Fic. 311e——Section of the chorion, showing blood clots between the villi.

Bie:
<x 7% times.

The umbilical cord is enlarged in its middle and is very
thin at its attachment to the chorion, which is also atrophic
at that point. Sections show that the center of the cord is
fibrous and that the enlargement is due to the extreme mucoid
degeneration of sides. Near its attachment to the body the
cord is infiltrated with round cells and the intestine within
the ccelom of the cord is irregular and gorged with them; the
lumen of the intestine is destroyed entirely.

The embryo is imbedded in the granular magma, and is
normal in form. Within, however, most radical changes have
taken place. The blood-vessels and heart are distended enor-
mously with blood, and the tissues are gorged with round

Fic. 311f.—Section of a villus which is invaded and partly destroyed by
leucocytes.

No. 1.] ORIGIN OF HUMAN MONSTERS. 305

cells. Liver, heart wall, intestine and mesenchyme are being
destroyed. The precartilage is more sharply defined than in
the normal embryo. ‘The spinal cord is dilated, the brain
and eye nearly solid and the ear vesicle is destroyed. The
ganglia and nerves are disintegrating. The epidermis is partly
wanting, and in the head region the skin is studded with
numerous papillomata. The face is adherent to the thorax.

No. 312.
Ovum, 25 x 15 xX 10 mm.; embryo, straightened and 8 mm.
long.
Dr. Stanton, Albany, N. Y.
“Abortion followed a blow upon the abdomen.” One side
of the ovum is very hemorrhagic and the other side thin.
The villi are few in number, fibrous, without a syncytial cov-

Fic. 312.—Solid ovum with embryo hanging from it. Enlarged nearly 2
diameters.

ering and possibly invaded by leucocytes. The main wall of
the chorion appears to be necrotic.

The embryo is straight, showing three gill arches and some
myotomes. Its tissues do not stain well, but the spinal cord
can still be outlined. The tissues appear to be infiltrated with
round cells.

No. 316.
Embryo, C. R., 44 mm.
Dr. Simms, Baltimore. |
There are peculiar patches upon the skin, the cord is
atrophic, feet and hands club-shaped and one hand is ad-

306 MALL. [VoL REX.

Fic. 316a—Front view of the embryo. Slightly enlarged.

Fic. 316b. Fic. 316c.

Fic. 316b.—Right side. Notice smooth face with eye obliterated and fold
of skin under the axilla.

Fic. 316c._—Left side. The eye is nearly closed and the hand has become
adherent to the side of the head.

No. 1.] ORIGIN OF HUMAN MONSTERS. 307

Fic. 316d.—Section of one of the elevations of the skin of the head
shown in Fig. 316c.

herent to the side of the head. Sections of the cord show

that it is fibrous and infiltrated with round cells along the

course of the blood-vessels.

The skin is thickened and much of the epidermis has fallen
off. At points the epithelial cells form mounds without any
horny changes in them. The muscles, blood-vessels and
nerves of the extremities are converted into one fibrous mass
composed of spindle-shaped cells, giving much the appearance
of myomatous tissue, infiltrated at points with round cells.

The cartilages are still hyaline, richer, however, in cells
than is normal. The bone formation is very extensive, which
at the border line between it and the cartilage shows peculiar
changes in the latter. There is a mass of this changed car-
tilage in the os calcis without any surrounding bone forma-
tion. In general the cartilages are deformed, due no doubt
in part to the distorted joints. Where the hand is adherent
to the side of the head the epidermis of the two is continuous
and blended. The skin and subcutaneous tissue are thick-
ened, being composed of one mass of round cells.

The form of the brain and its structure are pretty well pre-
served, while the tissues of the liver and intestine are necrotic
and macerated. It appears as if the growth of the embryo
had been retarded with a continued growth and change in
the connective tissues. Then, after its death, the embryo was
retained in the uterus for some time. At points all over
the body there are thickened spots in the skin which are

epithelial in nature, but they are located below the epidermis.
20

308 MALL. [Vo.. XIX.

No. 320.

Ovum, 70 x 50 x 40 mm.; embryo, 18 mm.

Dr. Gibbs, Baltimore.

The chorion is fleshy and thick, with irregular spots of villi
covering its surface. Some of the villi are fibrous and others
are swollen; all are deficient in syncytium. The decidua is
not typical, being well filled with fibrin, with occasional masses
of leucocytes. Within, the entire chorion is lined by the
amnion, which contains no magma. The umbilical cord is

Fic. 320a—Whole ovum. Natural size.

thin at its attachment to the chorion, but in its middle it is
swollen, which, upon microscopic examination, proved to be
a vesicle filled with a hyaline stringy mass tinged with car-
mine. Otherwise the cord is fibrous, and in its center are
seen the remnants of its blood-vessels. They are practically
obliterated.

The tissues of the embryo are pretty well dissociated, the
cord and brain being nearly solid, with occasional irregular
spaces representing the central canal. The outlines of the

No.

ORIGIN OF HUMAN MONSTERS.

309

Fic.

320b.—Embryo within the ovum. > 2 times.

310 MALL. [ Vou. DIDS

Fic. 320c.—Sagittal section of the embryo. X 8 times.

311

ORIGIN OF HUMAN MONSTERS.

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312 MALL. [Vov. XIX. ©

alimentary canal are obscure and its epithelial lining is nearly
lost. The blood-vessels are distended with blood in an ir-
reeular fashion. The liver is necrotic and free from blood.
The tissues of the body are all dissociated, which condition
obscures the muscles and nerves and sharpens the outlines of
the cartilages. The epidermis is intact.

No. 321.

Ovum, 40 x 40 x 20 mm.; embryo, 2 mm.

Dr. Wentz, Hanover, Penna.

The ovum is covered entirely with villi and contains some
reticular and much granular magma. The whole chorion is
lined by the amnion and the embryo is attached to it at its
middle. Traces of the central nervous system can still be
seen, and in front of it there is a structure which may repre-
sent the heart encircled by a large space, the ccelom, this ex-

Fic. 321a—Photograph of the ovum. X 2 times:

No. 1.] ORIGIN OF HUMAN MONSTERS. 313

Fic. 32tb—Embryo attached to the chorion. X 4 times.

tending to the umbilical cord. The tail end of the embryo is
nearly solid. A large share of the dissociation may be due to
the dilute alchohol (50 per. cent) in which the embryo had
been placed ten days before I got it. This, however, could
not alter the general shape of the embryo and its attachment
to the chorion.

Fic. 321c—Section of the embryo, main wall of the chorion and villi.
x9 times.

314 MALL. [Vor. AIX.

No. 323.

Pear-shaped hydatidiform mole, 120 x 90 x 65 mm.

Dr. Van Williams, Baltimore.

The fresh specimen was brought to the laboratory and was
found to be composed of enlarged villi, most of which meas-
ure about 5 mm. and a few fully 20 mm. in diameter. On
one end the specimen is fibrous, from which the villi extended
into a bloody mass.

Fic. 323—Photograph of the mole. Natural size.

The villi are very irregular in form, the mesoderm being
hyaline, in which there are numerous spindle-shaped nuclei.
Some of the “large villi” have in them a lumen which has
all of the characteristics of the ccelom; in fact, it appears as
if the main wall of the chorion ramified in all directions with
the growth of the villi. One of these openings is 15 x 10 mm.
and another just beside it is 7 x 2 mm. in diameter.

No. 1.] ORIGIN OF HUMAN MONSTERS, 315

Between the villi there are great masses of necrotic syn-
cytial cells. There is more or less blood between the villi and
occasionally small masses of leucocytes may be seen. A few
of the villi are being invaded by their epithelial coverings.

No. 324.

Ovum, hemorrhagic and fleshy, 45 x 45 X 22 mm.,; embryo,
rounded and 3% mm. long.

Professor Brédel, Baltimore.

The walls of the chorion are thin and fibrous and are lined
by the amnion. The villi are few in number, fibrous, devoid
of syncytium and imbedded in a large quantity of blood. Un-
fortunately the embryo was lost while being imbedded, but
the excellent drawing of it tells pretty well that its tissues and
organs are markedly changed and deformed.

No. 325.

Ovum, 55 x 55 x 35 mm.; embryo, CeRee73 mim:

Dr. Ballard, Baltimore.

“The specimen was obtained from the same woman that
gave No. 308. Last menstrual period, September 15; abor-
tion, November 27, 1905. Periods regular monthly.”” The
specimen was clean, well covered with villi and well hardened
‘n formalin. The amnion and ccelom are filled with magma
reticulé, in which is embedded the trunk of an embryo at-
tached to the chorion by a thin cord. On the opposite side of
the ovum the head is located, also imbedded in magma. Over
the body of the embryo there is a greenish-colored nodule
4 mm. in diameter, which proved to be the degenerated um-
bilical vesicle. The legs are poorly formed and stubby.

Sections of the chorion show that the mseoderm of the villi
is hyaline, in which remnants of blood-vessels may be seen,
with a normal number of round nuclei scattered through ite
The syncytium also appears to be normal. Between the villi
some mucus may be seen, in which there are leucocytes. No
decidua is attached to the villi.

The cord is thin at its attachment to the chorion, and it is
slightly enlarged midway between the chorion and the em-

MALL. [Vor. XIX.

316

Collapsed ovum
_-, with embryo

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Fic. 324a.—Ovum within the distended uterine tube. Natural size. After Kelly.

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Fic. 324b.—The embryo attached to the chorion. X 7 times. After Kelly.

No. 1.] ORIGIN OF HUMAN MONSTERS.

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Fic. 325a.—Photograph of the whole ovum. Natural size.

bryo. Here it contains large mesodermal spaces, which at
points are infiltrated with round cells. The umbilical vesicle
is present only in outline. Its lumen is partly filled with
debris. However, some beautiful multipolar mesoderm cells
may be seen.

Fic. 325b—Body of the embryo within the ovum. Natural size. There
is a large amount of magma within the ccelom, and the lump of it
overhanging the cut edge of the chorion contains the umbilical vesicle.

318 MALL. (Vor. XIX.

The epidermis covers the embryo only in part; a shell of
granular magma covers the rest of the body. ‘The tissues of
the body are greatly dissociated and macerated, which has
caused almost complete obliteration of the outlines of the
epithelial lining of the alimentary canal. The central nervous
system is nearly solid and the large blood-vessels are gorged
with blood. The liver is necrotic. The mesodermal tissues
are obscured, with the exception of the cartilages, whose out-
lines are sharpened.

No. 328.

Embryo, 44% mm. long.

Dr. Pohlman, Bloomington, Ind:

The chorion extends into irregular fibrous villi, which are
covered with a necrotic decidua infiltrated more or less with
leucocytes. The main wall of the chorion is about normal
in structure and contains numerous blood-vessels. Within
the amnion nearly reaches the chorion; the degenerated um-
bilical cord is attached to the amnion, but not to the chorion.
The umbilical vesicle is well imbedded in magma, is very
rich in blood-vessels and on its outside has many papilliform

Fic. 328a.

Embryo attached to the chorion. XX 4 times.

processes, some of which seem to blend with the chorion. In
fact, it appears as if the blood-vessels of the umbilical vesicle
passed directly over into those of the chorion.

The embryo is somewhat deformed, and it is difficult to
follow the outlines of some ot its ;aiscera 1 he veeniral

No. 1.] ORIGIN OF HUMAN MONSTERS. 319

nervous system is dilated and is converted into a mass of
round cells lying in the mesoderm without any epithelia
lining; the otic and optic vesicles are likewise filled with
round cells. The larger vessels are filled with blood, and the
tissues are fairly well infiltrated with round cells. The epi-
dermis is intact. Dissociation of the tissues has taken place
to such a degree that it is difficult to outline all of the organs
with certainty.

The

The walls of the umbilical vesicle are rich

in blood-vessels, which communicate directly with those of the chorion.

328b.—Section of the chorion and adjacent umbilical vesicle.

chorion is hemorrhagic.

Fic.

320 MALL. [ Vou, XTX.

Fic. 330Ab.

Fic. 330Aa.

Fic. 330Aa—Photograph of ovum. Natural size.
Fic. 330Ab.—The embryo. Nearly two diameters.

Fic. 330Ac.—Section of the embryo. XX 6 times.

No. 1.] ORIGIN OF HUMAN MONSTERS. 321

No. 330.

330A. Ovum, 60 x 55 x 50 mm.; embryo, C. R., 12 mm.

330B. Ovum, 55 x 50 x 45 mm.; embryo, C. R., 12 mm.

Dr. West, Bellaire, Ohio.

“The woman from whom these twin specimens were ob-
tained is about 25 years of age. Fifteen months ago she gave
birth to an eight-months child, which lived for two days. Her
last regular menstrual period took place during the middle
of September. The October and November periods were
missed. About the middle of December, at her regular time,
bleeding began, which continued until January 21, when these
two ova were aborted. I am quite positive, but not certain,
that woman has syphilis.”’

Both ova have smooth surfaces, being composed of thin
walls, upon which there are occasional villi. In both speci-
mens the villi are imbedded in a mass of pus, in which may
be found irregular villi, much necrotic syncytium, fibrin and
blood. Many leucocytes are found in the mesoderm of the
villi. The main wall of the chorion and the amnion of both
specimens are of irregular thickness and are well blended with
each other.

The changes in the two embryos are very similar. In both
the epidermis is intact and the dermis is thickened. In front
of the head in the region of the deformed mouth there are
peculiar thickenings of the epidermis. Both spinal cords are
markedly dissociated. The dissociation of the brains is so
extensive that in consequence the cerebral vesicles and mid-
brains are nearly destroyed and the hind-brains occupy spaces
in the centers of the deformed heads.

The large vessels and heart are gorged with blood. In B
the wall of the ventricle is well infiltrated and in A nearly
destroyed by the migrating cells. The outlines of the organs
and tissues are very obscure, the whole being more or less
filled with round cells. Some of the liver tissue is necrotic.

No. 334.

Fleshy mole, 50 x 40 x 30 mm.; embryo, 5 mm.
Dr. Merrill, Stillwater, Minn. 4

322 MALL. [VoL. XIX.

Fic. 330Bb.

Fic. 330Ba.

Fic. 330Ba.—The ovum. Natural size.
Fic. 330Bb—The embryo. Nearly two diameters.

Fic. 330Bc.

Fic. 330Bc.—Sagittal section of the embryo. X 6 times.

No. 1.] ORIGIN OF HUMAN MONSTERS. 323

“Last period four weeks ago. About ten days ago some
bleeding, which repeated itself at intervals, and was finally
followed by the abortion.”

Examination of the mass proves that it is made up mostly
of uterine mucous membrane, decidua, blood and pus, and
contains a cavity 15 mm. in diameter. The chorion can still
be made out as a fibrous band, infiltrated on the outside with
leucocytes, and on the inside with small masses of syncytial
cells. At points the chorion forms branches, which ramify
partly through the mole. These are accompanied with syn-
cytial cells and leucocytes.

The embryo is pretty well destroyed, of the five-weeks
stage, and infiltrated with round cells. The head and back
have fallen off, leaving only the viscera attached to the um-
bilical cord.

No. 336.

Ovum, 35 X 25 x 15 mm.; embryo, 8 mm.

Dr. West, Bellaire, Ohio.

The ovum is smooth, one end being covered with well-
developed villi. Their mesoderm is hyaline, with scattered
nuclei containing some remains of blood-vessels. The main
wall of the chorion is fibrous and infiltrated with blood-cells
from the embryo. Within there is a cavity (15 x Io mm.)
filled with granular magma and containing the umbilical
vesicle and the embryo, which is closely encircled by the
amnion.

The embryo is somewhat distorted, with large blood-vessels
filled with blood and tissues infiltrated with rounds cells. The
muscle wall of the ventricle of the heart is normal in appear-
ance and there is every evidence that it kept beating until the
last. What is especially noteworthy is that the circulation
with the chorion has been cut off, the cord being atrophic and
infiltrated, but instead the large omphelo-mesenteric vessels
are filled with blood and spread over the yolk sac. The walls
of this, however, are necrotic.

21

324 MALL. [Vor. XIX.

Fic. 336.—Section of the deformed embryo. XX 12 times. The mass
attached to the exterior of the amnion is a portion of the umbilical
vesicle.

No. 1.] ORIGIN OF HUMAN MONSTERS. 32!

ut

No. 338a.

Ovum, 45 x 45 mm.; embryo, C. R., 18 mm.

Professor Minot, Boston.

The specimen is from a patient suffering with arterio-
sclerosis, who died of cerebral apoplexy in the Boston City
Hospital. Pregnancy said to be of from six to eight weeks
duration.

Fic. 338a.—Photograph of the specimen. X 2 times.

The chorion is normal in appearance and in structure. The
cord of the embryo shows a marked constriction, which in
sections appears to be fibrous. The embryo in general is
normal in appearance, with the blood-vessels well distended
with blood. The central nervous system is dissociated and
somewhat macerated. The wall of the heart ventricle is also
dissociated, that is, it is infiltrated with round cells.

326 MALL. [Vor. XIX.

Fic. 339.—Photograph of the embryo. X 2 times.

No. 339.

Chorion;: 50°, 30: x 30min: embryo, Cy Rei, mn:

Professor Minot, Boston.

The chorion is thin, is covered by but few villi and is
hemorrhagic on one end. In structure it is somewhat hya-
line at points and at others somewhat fibrous. The cord is
thickened and also fibrous. The walls of its blood-vessels are
dissociated and the blood from them is infiltrating the sur-
rounding tissues. The embryo is somewhat distorted but
normal in form. Within the tissues are dissociated and
macerated. The large blood-vessels are distended with blood,
and within the liver and heart the blood cells from them have
extended into the surrounding tissues.

No. 340.

Stumpy embryo, 6 mm. long.

Professor Minot.

The embryo is well infiltrated with round cells, and the dis-
sociation of the tissues is quite complete. Large blood-vessels
can still be outlined, and the central nervous system is prac-
tically solid.

No. 1.] ORIGIN OF HUMAN MONSTERS. 327

Fic. 340—Sagittal section of the embryo. X 17 times.

No. 341.

Ovum, 70 x 60 x 50 mm.; embryo, 14 mm.

Professor Minot.

The ovum is pear-shaped and smooth, being covered with
some decidua and at points with hemorrhagic masses. Its
tissue does not stain well, but it appears as if some of the villi
were fibrous and others cedematous. There is not much syn-
cytium present. Possibly there are masses of leucocytes in
the decidua.

Within there are two stumpy embryos, both of which have
dilated cords which come to a point where they are attached

328

MALL. [Vor. XIX.

Fic. 341a—Photograph of the ovum. Natural size.

I'ic. 341c—The twin embryos. Nearly two diameters.

No.

I.]

ORIGIN OF HUMAN MONSTERS.

Po Cao ee

Fic. 341c.—Curious invagination of the epidermis on top of the head of one of the embryos.

330 MALL. [Vor. XIX.

to the chorion. These dilatations show the usual mucoid
changes, with cavity formation. The embryos are disso-
ciated and macerated. ‘The large blood-vessels are filled with
blood, and it appears as if the migrating cells had infiltrated
much of the tissues.

No. 342.
Ovum, 30 x 20 x 20 mm.; pedicle within, 5 x I mm.
Professor Minot.
The specimen is from a tubal pregnancy and has a very
thin fibrous chorion, with traces of blood-vessels, and is prac-
tically without villi. Within there is a thickened fibrous

Fic. 342—Chorion, amnion, cord and remnant of the embryo. X I5
times.

amnion, to which the process, the umbilical cord, is attached.
The cord is also fibrous, contains remnants of its blood-ves-
sels and has attached at its free end a curious group of round
cells, which probably represents what remains of the embryo.

No. 343.

Ovum, 55 x 45 x 35 mm.; embryo, II mm.

Professor Minot.

The chorion is of unequal thickness and mostly smooth.
Sections show that not only is the decidua attached to it, but
also portions of the uterus. The decidua is necrotic and infil-
trated with numerous leucocytes. Below the decidua there

No. 1.] ORIGIN OF HUMAN MONSTERS.

Fic. 343a.—Photograph of the embryo attached to the chorion.
times.

Fic. 343b—Section of the embryo. X 8 times.

331

332 MALL. [Vor. XIX.

Fic. 343¢.—Photograph of a section of the chorion, showing the mucoid
mass infiltrated with leucocytes between the villi.

No. 1.] ORIGIN OF HUMAN MONSTERS. 333

;

Fic. 343d.—Section of the point of juncture of cord, amnion, chorion,
villi and decidua. XX about 20 times.

}

are distorted villi with fibrous mesoderm. The amnion is in
contact with the chorion. Between the villi there is a stringy
mucoid mass rich in leucocytes.

The stumpy embryo is attached by means of a fibrous um-
bilical cord. Its tissues are dissociated and infiltrated with
round cells; the blood-vessels and heart are greatly distended
with blood. The liver is necrotic. In front of the head the
tissue is broken away, leaving a pocket which contained the
fore-brain. Above this the brain protrudes. The cord and
fourth ventricle are distended and dissociated. The epiderniis
is intact.

No. 344.

Ovum, 45 x 45 x 45 mm.; embryo, C.R., 16 mm.

Professor Minot.

The wall of the chorion is very thin, with a few fibrous
villi scattered over it. It contains no blood-vessels. The
long thin umbilical cord is fibrous and shows remnants of
blood-vessels.

~The embryo has a rounded head and stumpy legs. Its
tissues are dissociated, the brain being distended and macer-

334 MALL. [Vor. XIX.

ated, too. The medulla has expanded towards the mouth.
Heart and blood-vessels are distended and in many places the
walls are destroyed and the blood cells extend into the sur-
rounding tissues. This is very marked in the liver. The legs
are filled with an even mass of round cells, 7. ¢., the tissues are
dissociated. Some of the epidermis has fallen off.

Fic. 344.—Photograph of the embryo attached to the chorion. > 2 times.

No. 345.
Ovum, 60 x 50 x 50 mm.; embryo, 19 mm.
Professor Minot.
The fleshy ovum is composed largely of decidua, in which
are buried plugs of mucus, pus and necrotic villi of the
chorion. The embryo is normal in shape. The tissues of the

No. 1.] ORIGIN OF HUMAN MONSTERS. 335

embryo are macerated, but on account of the distended me-
dulla which encroaches upon the mouth I think it likely that
the tissues were dissociated before they became macerated.

No. 346.

Embryo, C. R., 13 mm.

Professor Minot.

A piece of hemorrhagic chorion, which may have been 50
mm. in diameter, is attached to the embryo. Its tissues are
macerated, but they are well enough preserved to show that
much mucus and pus are between some of the villi. The

Fic. 346.—Embryo attached to the ovum. X 2 times.

structures of the chorion, amnion and cord appear normal,
but the umbilical vesicle is filled with a necrotic mass.

The embryo is dissociated and macerated. The central
nervous system is dilated and the heart is distended with
blood, some of which infiltrates the surrounding tissues.

336 MALL. [Vov. XIX.

No. 347.

Ovum, 40 x 35°X 30 mme}embryo, CR orn aun eke tae
head is replaced the C. R. measurement will be less than
8 mm.

Professor Minot.

The decidua is hemorrhagic and necrotic at points and well
infiltrated with leucocytes. The villi and main walls of the

Fic. 347.—Embryo within the chorion. XX 2 times.

chorion are fibrous and at points infiltrated with leucocytes.
Very little syncytium is present, and but few traces of blood-
vessels are found in the chorion.

The embryo is dissociated and macerated, with dilatation of
the central nervous system and extension of the medulla. The
blood-vessels are distended and the blood cells are continued
through their walls into the surrounding tissues.

No. 1.] ORIGIN OF HUMAN MONSTERS. 337

No. 348.

Ovum, 50 x 30 x 25 mm.; embryo, I2 mm.

Dro Bearce; Albany,Na M4;

The specimen is smooth, being covered with numerous small
hemorrhagic spots and irregular masses of small villi. Sec-
tions show that the decidua is infiltrated with leucocytes, with
a consequent fibrous degeneration of the villi of the chorion.
The villi, as well as the main wall of the chorion, are being
invaded by leucocytes and frequently by syncytial cells.

The dissociation of the tissues of the embryo is extreme,
the blood from the blood-vessels having passed through their
walls to infiltrate the surrounding tissues. This is especially
well marked in the heart and liver. The nervous system is
pretty well broken up and the epidermis has fallen off.

No. 357.
Ovum, 90 xX 40 x 40 mm.; embryo, C. R., 17 mm.
Dr. Russell, Baltimore.
“The specimen came from an unmarried woman twenty-
two years old, who said that she was glad it had come away,

Embryo within the chorion. Natural size.

rau as 72

for it saved her the trouble of having an abortion induced.
Her menstruation was irregular, sometimes every two weeks,
sometimes every six weeks. The last period occurred about

338 MALL. [VoLt. XIX.

the middle of January. On March 29 she began to bleed
and aborted on April 19. Apparently her uterus is normal.”

The unruptured specimen is inclosed in a layer of decidua
and is covered with villi of unequal size, some being very
large, as the photograph shows. Within there is a stumpy
embryo without a neck and with atrophic leg buds. The
cord is transparent and partly filled with granules, which indi-
cates that the embryo had been dead for some time before
the abortion.

The mesoderm of the chorion and amnion is thickened, of
even structure, and contains no blood-vessels. In fact, its
coelomic cavity is entirely obliterated. The main wall of the
chorion is very thin, often being composed of epithelial cells
only. The mesoderm of the villi is unusually fibrous and con-
tains no blood-vessels. The very large villi are degenerated,
often hollow and do not stain. The syncytium is very deficient
in quantity; at points it invades the mesoderm. Over the villi
there is a mass of fibrin and disintegrated blood. Leucocytes
are not numerous, even in the decidua, which appears to be
normal.

The tissues of the embryo are not only dissociated, but also
macerated, and they do not stain well. The sharp boundaries
are lacking, showing that adjacent tissues have begun to
coalesce. In fact, the whole head down to the thorax seems
to have been converted into a bag in which fragments of car-
tilage and nerve tissue may be seen. The front of the head
is adherent to the thorax immediately over the heart. The
contours of the cartilages, liver, heart and adrenal can be made
out, but those of the blood-vessels are obscure.

According to the menstrual history this embryo was in the
seventh week when bleeding began, which was followed by
the abortion three weeks later. However, the degree of the
development of the cartilages and other structures places the
embryo in the sixth week. The lack of inflammatory reac-
tion, and the inactivity of the syncytium, suggests that the
continued bleeding may have been the primary difficulty,
which was followed by death and degeneration of the embryo.

No. 1.] ORIGIN OF HUMAN MONSTERS. 330

No. 358.

Ovum, 30 x 16 x 10 mm.

Dr. Swett, Bangor, Me.

“Pregnancy of six weeks duration.” The outer surface of
the ovum is smooth and the specimen runs out into a pedicle
which was undoubtedly attached to the uterus. Sections show
that the villi are matted together, with much blood and syn-
cytium between them. Around this there is a fibrous decidua
in which there are many leucocytes. The mesoderm of the
chorion is somewhat fibrous, the change being especially well
marked in some of the villi. No blood-vessels are present in
the villi.

The cavity within (ceelom) measures 8 x 6 x 6 mm., is
lined by a layer of reticular magma, but contains no trace of
the amnion nor embryo.

No. 361.

Ovum, 10 mm. in diameter.

Dr. Egbert, Washington.

“The ovum was found in a mass of blood within the
abdominal cavity, due to a tubal abortion. The operation
was performed just 41 days after the beginning of the last
menstrual period.”

The specimen came into my hands after it had been in
water for 24 hours. It was well covered with villi and filled
with a mass of dense reticular and granular magma. No
embryo could be found by direct observation. The specimen
was macerated too much to allow careful microscopic exami-
nation.

No. 364.

Ovum, 90 x 50 x 40 mm.; embryo, 16 mm.

Dr. Merrill, Stillwater, Minn.

The ovum is covered with a few ragged villi, over which
there is some decidua which is more or less detached. Dr.
Merrill had placed the specimen in formalin and sent it to
me accompanied with the following letter, dated July 6, 1906:

22

340 MALL. [VoL. XIX.

“Yesterday I sent another specimen by express. It seemed
to me that it would be a good specimen for you. April 7 was
the date of the last menstruation; the abortion followed on
July 5, 1906. The first flow and pain appeared on the night
of July 4. The woman has been married four years; this was
her first conception. Both she and her husband are very
anxious to have a child, so the miscarriage could not have
been aided. There was no incident, accident or otherwise to
give cause for the abortion. The woman is unusually healthy
and the miscarriage took place without chill or rise of tem-

Fic. 364a.—The ovum. Natural size.

perature. The specimen was placed in formalin, Io per cent,
within two hours after its expulsion.”

This history did not satisfy me, so I wrote Dr. Merrill
asking a number of questions, for it is from specimens like
this that we may hope to find the cause for such malforma-
tions. His second letter, dated October 24, 1906, reads as
follows: “This specimen is from the first conception, after
several years of married life. The woman had been operated
upon several years ago for appendicitis. She has not been
altogether regular with her menstrual periods, and there 1s
some pain connected with them. She had been treated, some

No. 1.] ORIGIN OF HUMAN MONSTERS. 341

Fic. 364b.—Front view. XX 3 times.

time before I saw her, for vaginal discharge; there may have
been endometritis. Prior to her conception I gave her some
treatment for leucorrhceal discharge, also made some slight
dilatation of the cervix. She had a long cervical os with a
narrow canal. There was some vaginitis and, as I remember,
some endocervicitis rather than endometritis; none of them

Fic. 364c.—Right side. > 3 times.

342 MALL. [Vor. XIX,

Fic. 364d.—Left side. > 3 times.

very marked. Probably there was enough uterine trouble to
cause the delayed development of the embryo and the abor-
tion. It was a natural abortion, as the woman was very
anxious to have a child. She is what I call a perfectly
healthy woman compared with the average woman of the
day. The husband is ordinarily healthy, but about a year ago,
his wife states, he had some trouble with his genital appa-

Fic. 364e.—Section to the left of the middle line.

No. 1] ORIGIN OF HUMAN MONSTERS. 343

Fic. 364f—Section near the middle line.

ratus. He has night emissions and I judge took medicine
for them. As far as I can ascertain, from her outline, he has
not had a venereal disease. If so, he did not contaminate her.
If he has, as she states, night emissions, perhaps the virility
of his semen is below par.”

These letters give the difficulties in obtaining histories in
these cases, but they indicate that the cause of the change in

Fic. 364g.—Sagittal section.

344. MALL. [Vo.. XIX.

Fic. 364h.—Section through the villi, showing large amount of mucoid
substance rich in leucocytes between them.

No. 1.] ORIGIN OF HUMAN MONSTERS. 345

the embryo is to be sought in the chorion, which probably
failed to attach itself well to the uterus.

Sections of the chorion show that the villi are far more
numerous than was suspected from the simple inspection with
the naked eye. The main wall of the chorion is thin and
atrophic and is lined with the amnion, which is fully detached
where it connects with the umbilical cord. However, it must
have been attached at one time, for remnants of blood-ves-
sels from the embryo are seen in the villi of the chorion.
The mesoderm of the villi is very fibrous and the villi are
matted together by a slimy mass rich in blood and leucocytes
with fragmented nuclei. The syncytium is well developed
and extends into the mass of blood and slime. The decidua
over the chorion has large sinuses within its walls, is quite
hemorrhagic and at points has large islands of leucocytes,
usually situated along the course of the blood-vessels.

The photographs show the condition of the embryo. Hare-
lip, displaced ears, protruding viscera in front and spina bifida
behind. The large blood-vessels and heart are still filled with
blood and there is quite a general infiltration of the tissues
with round cells. The vessels of the embryo end in the cord
and do not reach to the chorion. In general, there is mainly
a destruction of the tissues due to the irregular growth of the
embryo.

The central nervous system has been converted, in great
part, into a mass of connective tissue, with remnants of the
cord below and a rudimentary brain above, which forms a
shield upon the protruding mass. A portion of this shield
has grown into the connective tissue below, forming a gland-
like structure.

The clavicle, mandible and maxilla have begun to ossify
and some of the muscles are well developed.

No. 365.
Embryo, 14 mm.

Professor Pohlman, Bloomington, Ind.
This embryo, with spina bifida, iniencephaly and anenceph-
alus, and extremities of normal form, has a straight body

346 MALL. [Vor. XIX.

Fic. 3654.

Front view of the embryo. > 2 times..

Fic. 365b.—Section through the middle line of the head. > 6 times.

No. 1.] ORIGIN OF HUMAN MONSTERS. 347

Fic. 365c.—Section through the middle line of the neck. X< 6 times.

Fic. 365d.—Section through the hand.

348 MALL. [Vor. XIX.

and is attached to the end of a very large umbilical cord.
Sections show that the spinal cord is absent, but there is a
solidified brain which is more or less infiltrated with round
cells at its periphery. The same is the case with the eyes.
The mouth is closed by the tongue, which has become ad-
herent to the lips. The nodules in front of the body are
composed of necrotic epithelial cells.

Some of the tissues of the body are necrotic, but most of
them are infiltrated with round cells, and those of the head
are quite fibrous in character.

The walls of the alimentary canal and the lungs are also
pretty well filled with irregular patches of round cells. Espe-
cially well marked is this change in the region of tendons
and perichondrium, showing that there is an irregular growth
of the mesodermal tissues. The clavicle, maxilla and mandible
are well ossified, which should not be the case in so small an
embryo.

No. 366.

Embryo, 9 mm.

Professor Pohlman, Bloomington, Ind.

Sections of the chorion, which is fleshy in appearance, show
that its main wall is very thin and that it is lined with the
amnion. The villi, few in number, are fibrous or hyaline, are
covered with some syncytium, and the spaces between them
are filled with blood. Some of the villi adhere by means of
the syncytium to the decidua, which is fibrous and necrotic.
There is no leucocytic infiltration of the chorion nor the
decidua.

The embryo is pretty well infiltrated with round cells and
the tissues are dissociated. The tissttes are well preserved
and appear to have been very much alive. There is a con-
siderable quantity of blood within the cavity of the heart and
in the blood-vessels. The central nervous system is disso-
ciated. The lower jaw is large and is adherent to the head
above and to the trunk below. The arms and legs are
atrophic.

No. 1.] ORIGIN OF HUMAN MONSTERS. 349

Fic. 366a.—Sagittal section of the embryo. %X 10 times.

Fic. 366b.—Section of a villus. X 250 times. Notice large epithelial
cells scattered in with the stroma.

350 MALL. [Vor. XIX.

No. 367.

Ovum, 10 x 7 xX 5 mm.

Professor Broédel, Baltimore.

The ovum from a tubal pregnancy came to me unopened
and with some adhering cells and blood clot it was cut into
serial sections. The chorion was found to be torn on one
side, but its interior is packed with a dense reticular magma.
No trace of an embryo was found.

Vili

Corpus Luteum

Fic. 367a—Ovary and tube, clot within and ovum. Natural size.

The mesoderm of the main wall of the chorion is of normal
thickness, but on the side towards the ccelom it is not sharply
defined. Frequently strands of cells are found partly sepa-
rated and running out into the magma. The tissue of the
mesoderm of the villi is not as clearly defined as in normal

No. 1.] ORIGIN OF HUMAN MONSTERS. 351

Fic. 367b.—Section of a portion of a villus as indicated by the adjoined
outline, V. X 250 times. E&, epithelial covering; M, mesoderm; S,
space within formed by a destruction of tissues.

Fic. 367¢c—Outline of a villus showing the portion from which Fig. 367b
was drawn.

352 MALL. [Vor. XIX.

specimens, some of them having undergone marked degenera-
tion. The villi are developed better on one side of the chorion
than on the other, and here they contain structures which are
undoubtedly blood-vessels.

The syncitium is not very marked and is held together by a
slimy mass which contains some leucocytes. The surround-
ing tissue, the “decidua,” is full of fibrin and contains numer-
ous fragmented nuclei and some blood.

It is natural to read into thi specimen the following his-
tory: The embryonic mass grew long enough to send its
blood-vessels into the chorion and then the nutrition was cut
off because the villi did not attach themselves properly. That
this was the case is shown by the capsule of necrotic tissue
‘which encircles the villi. As a result of impaired nutrition
the embryo was destroyed, leaving only the isolated chorion
filled with reticular magma.

No. 369.

Ovum, 7 <3 x3.

Professor Brodel, Baltimore.

The specimen was removed by operation from a tubal preg-
nancy on October 9, 1906. The woman’s last period began
September 17. The distended tube measured 25 mm. in
diameter and when cut open a small lump, 2 mm. in diameter,
was seen on one side of its cavity. This was believed to be
the embryo, but serial sections proved it to be a small mass of
blood very rich in leucocytes.

The sections show the chorion pretty well folded upon it-
self, which is torn at several points. The torn edges are well
rounded, that is, they are healed and are therefore not due
to the operation. Few villi are left, and they, with the main
walls of the chorion, are very fibrous in structure. There is
but little syncytium present. The entire chorion is sepa-
rated from the wall of the tube by a thick layer of blood, and
the tube wall is well infiltrated with leucocytes. What is most
remarkable in this specimen is that the amnion lines the
chorion completely and all of the mesoderm of the chorion is

No. 1.] ORIGIN OF HUMAN MONSTERS. 353

well filled with blood-vessels from the embryonic mass, which
must have been present at one time.

No. 375.

Embryo, C. R., 13 mm.

Professor Gage, Ithaca, N. Y.

A piece of chorion accompanied the embryo, both of which
appear quite normal. However, sections of the chorion show
that the mesoderm of the villi is very fibrous, while that of its
main wall appears normal. The syncytium seems to be defi-
cient in quantity.

Sections of the embryo indicate that it is nearly normal,
with some dissociation of the tissues. The larger blood-ves-
sels are gorged with blood, and some of the tissues, especially
those in front of the head, are infiltrated with round cells.
The central nervous system is swollen and dissociated, as is
so frequently the case in many of the other embryos.

No. 377a.

Ovum, 30 x 22 x 14 mm.

Dr. Crawford, Cedar Rapids, Iowa.

The specimen is well covered with villi, which appear quite
normal to the naked eye, but upon microscopic examination
it is found that they are very fibrous and tipped with syn-
cytium; at points it forms islands with necrotic centers.

The interior of the ovum contains a considerable amount
of reticular magma, within which there is embedded a large
sac (5 mm. in diameter) containing a nodule (.5 mm. in
diameter )—the embryo.

Sections show that the whole chorion is lined with the
amnion except at the point of the “inclosed sac,” which proves
to be the exoceelom. The embryo is composed of an amor-
phous mass of cells which invade the mesoderm of the chorion.
It may represent the last remnant of the umbilical vesicle.
No traces of blood-vessels are seen in any portion of the
embryonic mass, nor in the mesoderm of the chorion.

354 MALL. [Vor. XIX.

No. 378.

Ovum, 12 mm. in diameter.

Professor Brodel, Baltimore.

The specimen came from a tubal pregnancy, is dumb-bell-
shaped, and had been opened by Professor Brédel, who found
no trace of an embryoein it. It was hardened immediately
and later cut into serial sections. At no point in the sections
could any trace of an embryo be found, although it is pos-
sible, but improbable, that it was lost while the fresh specimen
was being examined.

Ne

Fic. 378.—Outline of the tube, blood clot and ovum. Natural size.

The ccelom contains some granular magma. The meso-
derm of the main wall of the chorion is apparently normal,
but that of the villi is cedematous. There are no blood-ves-
sels present. At many points the syncytium is necrotic, fre-
quently rising from the villi, leaving small vesicles below.
The necrotic masses are held together by a slimy mass, within
which there are a great many small round cells, undoubtedly
leucocytes.

No. 379.

Ovum, 35 25 x ors) mim:

Dr. Meyer, Baltimore.

“Last period early in August; abortion, October 20, 1906.”

The specimen is well covered with villi and filled with a
considerable amount of reticular magma. Within there is a
sac, the amnion, measuring 10 mm. in diameter. It con-
tained a granular mass, which, when floated from alcohol into
water, took on the form of an embryo of the fourth week.

No. 1.] ORIGIN OF HUMAN MONSTERS. 355

Fic. 379.—Section of a portion of a villus. >< 250 times. The synctium,
S, is invading the mesoderm of the villus.

No internal structures could be seen and in handling the
embryo it fell into pieces. No doubt the embryo had been
dead for some time.

Sections show that the mesoderm of the umbilical cord,
main wall of the chorion and the villi are fibrous, with a
curious growth of the blood-vessels in some places. Within
them there are numerous fragmented cells, which may have
come from the blood of the embryo. The syncytium is very
extensive, necrotic at points and is not infiltrated with leuco-
cytes. In many places it dips deep into the mesoderm of the
villi and forms islands of epithelial nests. The wall of the
amnion is composed of two layers of cells and appears to be
normal.

23

356 MALL. {Vor cL

No. 395.

Ovum and decidua, measuring 17 x 10 x 7 mm.

Dr. Pearce, Albany, N. Y.

Dr. Pearce writes: “I am sending you to-day a small encap-
sulated mass, found among curettage material, which appears
to be a young ovum. I have refrained from attempting to
determine definitely whether or not it contains an embryo,
for fear of injuring a specimen which might be of value to
you.

“The specimen was removed April 20, 1907, six weeks after
the last menstruation. The uterus was emptied because the
patient had eclampsia three years ago, and since then has
had premature delivery of two dead children. The specimen
is preserved in 10 per cent formalin.”

The whole mass was stained in cochineal and cut into serial
sections, but no embryo was found in it. The sections show
it to be composed of numerous villi, decidua and inflammatory
tissue. Most of the villi are also fibrous and degenerated,
some few, however, contain blood-vessels filled with embryo’s
blood. The fragmentary walls of the chorion are very fibrous
and the growth of the syncytium is very irregular. Undoubt-
edly the ovum “collapsed” some days before the uterus was
scraped. The whole specimen is buried more or less in a
slimy mass rich in leucocytes, which indicates that the uterine
tissue was markedly inflamed.

No. 396.

Ovum, about 7 mm. in diameter, with the ccelom measuring
3x2mm._ Tubal pregnancy.

Dr. Castler, Baltimore.

“The tube was removed April 24, 1907, from a woman
twenty-one years old. Last period, March 5, followed by a
brownish discharge on April 11. Diagnosis of tubal preg-
nancy on April 23. The abdominal cavity was found well
filled with blood and the tube was still bleeding through the
internal ostium. The whole tube was removed and placed in
a 10 per cent solution of formalin.”

No. 1.] ORIGIN OF HUMAN MONSTERS. 357

The hardened tube is 40 mm. in length and 20 mm. in
diameter. It was cut into blocks 5 mm. thick and imbedded
in colloidin. Two of the blocks were found to contain the

we

~
~
wee

Fic. 396.—Section of the chorion containing the embryonic mass. X 35
times. E, remnant of the embryo; UV, umbilical vesicle.

ovum and these were cut out and reimbedded in paraffin and
cut into serial sections. The sections show that the ovum
has unusually long villi, fully 5 mm. long, which ramify

358 MALL. [Vor. XIX.

throughout the blood in the tube and in many instances are
attached to the decidua. The syncytium is well developed.
The walls of the tube are markedly distended, infiltrated with
red corpuscles and leucocytes, many contain fragmented nuclei,
which are also scattered throughout the decidua.

Within the ccelom of the chorion there is a double vesicle,
the large one, 2 x I mm. in diameter, showing all the char-
acteristics of the umbilical vesicle. Its layer of mesoderm
appears to be thickened and at numerous points it has become
adherent to the inner wall of the chorion. At these points
the blood islands extend over to the mesoderm and from them
blood-vessels ramify to all of the villi. These vessels are all
filled with nucleated blood cells. The smaller vesicle is about
a millimeter in diameter, is lined with cylindrical cells and is
covered with quite an even layer of mesoderm, in which there
are some quite large blood-vessels but no blood. Towards
one of its ends it is covered with a marked layer of cylindrical
cells. It may be that this second vesicle represents what is
left of the embryo. Around these two vesicles, filling the
whole ccelom, there is a dense reticular magma.

The main wall of the chorion and many of the villi are
somewhat fibrous in structure. Some of the villi are being
invaded by syncytial cells.

This specimen is especially valuable inasmuch as it shows
the early changes which take place in an ovum after it became
lodged in the uterine tube. No doubt owing to its faulty
implantation the nutrition of the embryo was affected and
it consequently grew in an irregular fashion. The umbilical
vesicle became adherent to the chorion and its blood-vessels
grew out into most of the villi.

No. 398.
Embryo, 5 mm. long.
Professor C. R. Bardeen, Madison, Wis.
The embryo is markedly changed and of the three-weeks’
stage. Most of the organs can still be recognized and the
embryonic ccelom is fairly definite. The front of the head is

No. 1.] ORIGIN OF HUMAN MONSTERS. 359

Fic. 398.—Outline of the embryo. X 8 times.

adherent to the thorax below and the face is pretty well
atrophied. The central nervous system is dissociated and
distended, as are also the heart, blood-vessels and the liver.

No. 399.
Embryo, 4 mm. long.
Dr. Thompson, Mt. Horeb, Wis. Bardeen Collection.
“The specimen is from.a woman twenty years old who has
been married ten months. She is a marked bleeder, other-

Fic. 399—External form of the embryo. X 8 times.

wise strong and healthy. The pelvic organs are normal. The
last period occurred during the first week in September and
the abortion followed October 9, 1906.”

360 MALL. [Vor. XIX.

The external form looks much like that of a chick. Sec-
tions show that the tissues are generally dissociated and also
macerated.

No. 400.

Embryo, 3.5 mm. long.

Dr. Kaumheimer, Milwaukee, Wis. Bardeen Collection.

“Last menstruation October 21; abortion December 19.
Placed in 10 per cent formalin an hour after the abortion.”

The external form is that of a normal embryo, but the
sections show that marked pathological changes have taken
place. The central nervous system is distended and partly

Fic. 400—Drawing of the embryo. X 8 times.

filled with round cells. The walls of the brain of the embryo
are dissociated and apparently are giving rise to the numer-
ous round and fragmented cells which are present. The heart
and large blood-vessels are distended and well filled with
blood. The tissues of the mesoderm are generally filled with
round cells as well as with numerous fragmented nuclei, the
infiltration including the myotomes and the peritoneal cavity.
The amnion and epidermis are intact.

No. 401.
Embryo, 5.5 mm. long.
Dr. Hay. Bardeen Collection.
Much of the chorion and many of the villi and the syn-
cytium are necrotic and infiltrated with many leucocytes. The
tissues of the embryo are dissociated, macerated and infiltrated

No. 1.] ORIGIN OF HUMAN MONSTERS. 361

with round cells. However, all of the organs are recog-

nizable. The umbilical vesicle is necrotic and filled with a
mass of broken-down cells.

No. 402.

Ovum, 40 x 25 x 20 mm.; embryo, 4 mm. long.

Dr. O’Shaughnessy, New Canaan, Conn.

“The woman, age 30, from whom the specimen was ob-
tained is well built, strong and healthy. Menstruated regu-
larly, but was married 3% years before she became pregnant.
After the birth of this child she had a slight discharge and
was attended by a physician, who stated that she had an
ulcerated cervix, for which he made local applications.
Shortly after this, two years after her first confinement, she
became pregnant again. This confinement, which was at-
tended by me, was rapid and normal in every respect. She
remained in bed for 15 days, the uterus not reducing in size
as it should normally.

“Since the second child was born she has had some dis-
charge, but became pregnant again about six or eight weeks
ago. This time, however, she aborted. She has never done
anything to prevent pregnancy, and both she and her husband
are anxious to have a large family. The patient is at present
unwell and still has her chronic discharge.”

The villi of the ovum are not well developed, being irregu-
larly distributed over its surface. Within, the ccelom is well
filled with reticular. magma. The embryo is club-shaped, its
head being much too large for the body, the external form
being very much like that of No. 399. The umbilical vesicle
is of normal size and shape, the heart is well outlined and the
extremities are just beginning to develop.

PLATES.

The plates include a number of illustrations which were
borrowed from the literature to illustrate various points in
this article. There are also some sections of normal embryos

with which to compare the numerous sections of pathological
specimens.

Prarroe

ErGen te Fic. 2.

Fic. 1—Human embryo 8 mm. long with spina bifida. After Torneau
and Martin (Journal d’Anat. et Physiol., XVII, 1881).

Fic. 2—Spina bifida in a human embryo 10 mm. long. After Fischel
(Ziegler’s Beitrage, XLI, 1907, Fig. 16).

Fics. 3 and 4.—Sections through the middle of the spina bifida shown in
Fig. 2. After Fischel (Ziegler’s Beitrage, 1907, Figs. 21 and 22).

364

PLATE II.

ovum.

Fic. 5.—Ovum in tubal pregnancy. From a drawing by Professor Brodel.
Natural size. After Kelly (Operative Gynecology, 2d edition, Vol. 2,
Fig. 635.)

Rupture

Fic. 6—Ovum in tubal pregnancy. Reduced one-tenth. (After Kelly’s
Operative Gynecology, Fig. 640.) :

Fic. 7—Tubal abortion. Natural size. (After Kelly’s Operative Gyne-
cology, Fig. 643.)

PLATE III.

Fig. 8—Normal human embryo 16 mm. long (No. 256). The head had
been crushed in handling and the brain escaped through the two open-
ings over the eyes.

Fic. 9—Sagittal section of a normal human embryo 7/ mm. long (No.
221).

306

PLATE IV.

Fic. 10.—Sagittal section through a normal human embryo 14 mm. long
(No. 144).

Fic. 11.—Sagittal section through a normal human embryo 35 mm. long
(No. 199).

367

THE OOGENESIS OF BUFO LENTIGINOSUS.
HELEN DEAN KING.

The present paper records the results of an investigation
of the odgenesis of the American toad, Bufo lentiginosus,
which was undertaken, primarily, in order to trace the history
of the chromatin from the odgonia to the maturation period
of the odcytes and thus to complete my study of the chro-
matin behavior in the germ-cells of this amphibian. The
work has necessarily involved a detailed study of the nucleoli,
since these structures are closely associated with the chromatin
at certain periods of development; and it has been extended
to include an investigation of the yolk formation, as the
material seemed especially favorable for this purpose.

This study was begun several years ago at Bryn Mawr Col-
lege, but was laid aside for various reasons until this past
year, when it was completed at the Biological Laboratory of
the University of Pennsylvania, where I was holding a Uni-
versity Fellowship for Research in Zoology. I take this op-
portunity to express my obligations to Professor E. G. Conk-
lin for many valuable suggestions during the course of my
investigations.

I. MATERIAL AND METHODS.

Bufo lentiginosus is found very abundantly in the vicinity
of Philadelphia; and, as the tadpoles are easily reared in the
laboratory, several different series of preparations have been
obtained consisting of larve killed at frequent intervals from
the time of hatching until metamorphosis. These series give
all stages in the development of the germ-cells up to the
early growth period of the odcyte. For the study of the later
development of the ova, young toads with a body length of
1.5-5.5 cm. were collected at various times from June until

370 KING. [Vou XIX.

September. In order to compare the development of the
ova in the young toad with that of the ova in the adult, por-
tions of the ovaries of mature females were preserved at
different times during the summer months. As the eggs ap-
pear to develop along similar lines in all toads, ovaries of
young females were used principally for these investigations,
since in them the ova are more nearly uniform in size than
they are in the adult, and in a single section it is possible to
find a large number of eggs in practically the same stage of
development.

The very conflicting results that have been obtained by the
investigators who have studied the development of the germ-
cells in amphibians can doubtless be attributed, in part at
least, to the great diversity of ways in which the material
has been preserved. Carnoy and Lebrun, who have studied
the germinal vesicle in the eggs of many different species of
amphibians, unhesitatingly recommend Gilson’s fluid as the
best fixative for the amphibian egg. I have not found that
this liquid gives a satisfactory fixation of the egg of Bufo,
as it usually causes a decided shrinkage of the nucleus and,
at certain stages, a distortion of the nuclear contents. A
number of different fixing fluids have been tried during the
course of these investigations, among which may be mentioned
Zenker’s fluid, corrosive-acetic (5 per cent acetic acid), cor-
rosive-formalin (Bouin’s method), picro-acetic, Flemming’s
solution, chromic-acetic, and Hermann’s fluid. Flemming’s
solution (strong formula) is the best fixative for the odgonia
and the early growth stages of the odcytes, although Zenker’s
fluid and Hermann’s fluid give very good results. After the
yolk has formed Flemming’s solution does not penetrate the
egg sufficiently well to give a satisfactory fixation. For this
later period I have found that the chromic-acetic solution
recommended in a previous paper (King, 49) gives the best
preparations. Corrosive-acetic acid is also a good fixative for
the egg at this period of its development, but it is especially
valuable for the maturation stages. Corrosive-formalin and
Picro-acetic do not give a satisfactory fixation of the egg of
Bufo at any stage of its development.

No, -2.] THE OOGENESIS OF BUFO LENTIGINOSUS. 371

Of the great variety of combination stains that have been
experimented with at different times in the hope that it might
be possible to differentiate the chromatin from the nucleoli,
safranin and gentian violet, used in the manner recommended
by Hermann (39), proved to be by far the best. This stain is
rather difficult to use, but when a satisfactory preparation has
been made, all of the plasmosomes are stained a vivid red and
stand out in sharp contrast to the chromatin which is a deep
blue, while the structures which I have called “compound-
nucleoli” are stained purple. Much of the material was stained
with iron hematoxylin and orange G. This combination does
not differentiate the nucleoli from the chromatin; but it gives
such clear, sharp outlines that it is of great value in studying
the early stages in the development of the oocytes when the
chromatin stains but faintly and cell boundaries are difficult
to determine. Borax carmine combined with Lyon’s blue,
safranin followed by Lichtgriin, and Delafield’s hematoxylin
with orange G. also give good preparations, particularly of the
later growth stages of the oocytes.

Il. THe PRIMORDIAL GERM-CELLS.

Owing to the large amount of yolk in the embryo and to
the vagueness with which the cell boundaries are defined, it is
impossible to trace the germ-cells in Bufo back to the segmen-
tation stages of the egg, as has been done in other more favor-
able forms. Not until a tadpole is five or six days old and has
attained a length of about 4 mm. can one point out definitely
the group of cells that will develop into the genital ridge.
At this stage of development the lateral plates of mesoderm
(Fig. 1, L. M.) are well defined; the cells are small, with
clear outlines, and they contain but comparatively little yolk.
In the endoderm (Fig. 1, E.) on the contrary, the cells are
very large; they are filled with yolk spherules which stain very
deeply with iron hematoxylin, and their boundaries are ir-
regular and difficult to determine. In the mid-dorsal region
of the embryo there is usually found at this time a ridge of

372 KING. [Vou XIX.

cells (Fig. 1, G) which lies directly beneath the aorta (Ao.)
and between the lateral mesodermal plates (L. M.). The cells
of this ridge resemble the cells of endoderm in all respects and
they are continuous with the endodermal cells which later form
the lining of the digestive tract: there is no probability that
these cells are of mesodermal origin, since they are always
sharply marked off from the lateral mesodermal plates. When
the tadpole is eight or nine days old this ridge of cells becomes
separated from the endoderm, and it then forms a median cord
of cells, the genital ridge, lying between the cardinal veins
and supported by the mesentery (Fig. 2 G). The cells of
the genital ridge are very conspicuous in sections at this time,
as they still contain numerous large, deeply staining yolk
spherules, although the neighboring cells have already absorbed
the greater part of their yolk.

Many investigators who have studied the origin of the
germ-cells in amphibians have asserted that these cells are
derived from a germinal epithelium which is a modifica-
tion of the peritoneal epithelium lining the body-cavity. This
is the view advocated by Waldeyer (91), Semon (84), Hoff-
mann (44), Kolessnikow (55), Leydig (60), Spengel (86),
Iwakawa (45), and more recently by Bouin (11). The last
named investigator, however, admits the possibility that the
first germ-cells in Rana are derived from endoderm, since in
early stages of development they have all of the character-
istics of the primitive endodermal cells. On the other hand,
Nussbaum (73) maintains that in amphibians, and also in
other vertebrates, the germ-cells are not derived from perito-
neal epithelium, but that they are developed from undifferen-
tiated embryonic cells which are set apart during early cleav-
age for this especial purpose. This theory has been supported
by the researches of Woods (95) on Acanthias, and by Beard
(7) on Raja batis. The latter investigator states: “The germ-
cells may be regarded as unicellular organisms which pass
one part of their life-history within a multicellular sterilized
stock, the embryo or metazo6n, formed by one of them at a
definite period in the life-cycle.”

No. 2] . THE OOGENESIS OF BUFO LENTIGINOSUS. 373

In Bufo, as in the turtle and in the frog according to the
investigations of Allen (1, 2), the germ-cells arise in con-
nection with the endoderm. Allen’s recent account of the
origin of the sex-cells in Rana pipiens agrees essentially with
what I have found in Bufo. I cannot be sure, however, that
in Bufo the ridge of germ-cells is separated. from the endoderm
“by the approximation of the lateral plates of mesoderm,” al-
though many sections give this impression. During this early
period of development, when so many organs are rapidly being
differentiated from embryonic tissue, it is impossible to tell
exactly what forces or combination of forces are at work shift-
ing the materials from one place to another. It is possible, as
Allen suggests, that the germ-cells themselves take an active
part in the processes which separate them from the endoderm,
since it is apparently only through their own activity that
they reach their final position in the embryo. Since Hertwig
(41), Boveri (12), and others have traced the germ-cells
back to segmentation stages, and Conklin (21, 22) has found
various organ-forming substances in definite areas in the un-
segmented egg, it seems meaningless to speak of organs as
arising from any definite “germ-layer,” although the conven-
ience of such a starting point for the study of the development
of any structure is obvious. Owing to the character of the
embryonic cells it is seemingly impossible to trace any organ
in Bufo back to early cleavage stages, and the sex-cells are
not clearly defined until the tadpole is about five days old.
At this stage of development the germ-cells still retain their
earlier embryonic character, and they are in contact with and
closely resemble the endodermal cells. Instead of asserting
that the germ-cells in Bufo are endodermal in origin, it seems
to me more in keeping with the results of the investigations on
other more favorable forms to assume that these cells in Bufo
are of like generation with the primitive endodermal cells and
that both kinds of cells arise from neighboring regions of
the unsegmented egg. It may sometimes be possible to deter-
mine the organ-forming regions in the unsegmented egg of
Bufo as Conklin has done in the egg of Cynthia.

374 FRING: [Vou. XIX.

When the genital ridge is first clearly marked off from the
endoderm it occupies a median position between the cardinal
veins and beneath the aorta (Fig. 2), as Bouin and Allen
have stated is the case in Rana. If a section of the ridge in
this stage of development is examined under high power one
finds that it is composed of two distinct types of cells, one
many times larger than the other (Fig. 3). The large cells,
which are filled with yolk spherules and have vaguely defined
boundaries, are the primordial germ-cells. The nuclei of these ,
cells have the “mulberry” shape which La Valette St. George
(78) discovered to be a characteristic of the nuclei in the
spermatogonia of Salamandra, and they are usually crowded
by the yolk spherules into one corner of the cell. The chromatin
in these nuclei is in the form of minute, faintly staining gran-
ules which are distributed on linin threads or along the nuclear
membrane. Each nucleus contains several rounded, deeply
staining nucleoli of various sizes. Judging from their stain-
ing reactions most of these nucleoli are plasmosomes, and only
one or two of the smaller ones are karyosomes. Scattered
among these germ-cells, and frequently flattened against them,
are numerous small cells which resemble in all respects the
cells of the peritoneal epithelium from which they doubtless
have been derived. These cells are very much smaller than the
germ-cells; they contain no yolk and they have an elongated,
deeply staining nucleus which is very large in proportion to »
the size of the cell. Doubtless these cells migrate into the
genital ridge after the formation of the mesentery, since there
are no cells of this type in the genital ridge at the stage of Fig.
1, and I have seen nothing that would indicate that they are
derived from the germ-cells.

Bouin has stated that he finds in Rana temporaria transi-
tional stages between peritoneal cells and primordial germ-
cells, and he believes that before the metamorphosis of the
tadpole new germ-cells are constantly arising from peritoneal
cells. These observations have not been confirmed by Allen
(2) in his study of the origin of the germ-cells in Rana pipiens,
and in Bufo I can find no evidence that the germ-cells are

No. 2] THE OOGENESIS OF BUFO LENTIGINOSUS. 375

derived from peritoneal cells at any stage of development. The
peritoneal cells in the genital ridge vary considerably in size
and some may be nearly twice as large as others. In all cases,
however, the cell contains comparatively little protoplasm and
no yolk; while the nucleus maintains a characteristic appear-
ance and stains very deeply, thus standing out in sharp contrast
to the larger, more irregular, and more faintly staining nuclei
of the germ-cells.

The development of the genital ridge proceeds from before
backward. Ina section of the anterior part of the ridge there
are usually from 5-8 large germ-cells (Fig. 3), while in a
more posterior section there are rarely more than three of
these cells. In older tadpoles the difference in the rate of
development of the different parts of the genital ridge is even
more strongly marked, since the anterior portion of the ridge
may have taken on its definite character as an ovary or a testis
while the posterior portion remains in an apparently indifferent
state.

When a tadpole is ten or eleven days old, the yolk spherules
begin to disappear from the cells of the genital ridge. and the
structure of the germ-cells can then be more clearly seen (Fig.
4). At this time the germ-cells are more rounded than they
were at an earlier period and, as they contain fewer and
smaller yolk spherules, the polymorphic nucleus is usually
found in the centre of the cell. With the exception of the
large plasmosomes, the nuclear contents still show little capac-
ity for staining either with plasma or with chromatin stains.
By this time many peritoneal cells have become flattened
against the germ-cells and have thus assumed the role of fol-
licle cells. The boundaries of these follicle cells become very.
indistinct, and in many cases the cytoplasm seems to disappear
entirely leaving the deeply staining nuclei in contact with the
germ-cell.

In early stages of development the germ-cells are not al-
ways confined to the genital ridge. At the right, in Fig. 4,
is a cell (Y) which lies considerably outside of the germinal
area and directly under the Wolffian tubule; in Fig. 5, at the

376 KING. [Vov. XIX.

left of the aorta are two germ-cells which lie above the level
of the genital ridge. Such germ-cells must eventually come
into the germinal area or degenerate, since cells of this char-
acter are never found outside of the genital ridge in later
stages of development. I have never found cells with the
characteristics of germ-cells in the mesoderm or in the ecto-
derm.

In a tadpole twelve to fourteen days old there is usually
found the beginning of a separation of the median genital
ridge into two ridges symmetrically placed one on each side
of the middle line (Fig. 5). This division of the genital ridge
is evidently brought about through the activity of the germ-
cells, although I have never been able to find any evidence
of amoeboid movement in these cells. A longitudinal section
through a tadpole thirteen days old (Fig. 6) shows that, at the
time the genital ridge is dividing, the germinal area extends
from about the level of the liver nearly to the posterior end of
the body-cavity. When the division is completed the anterior
portion of each genital ridge contains from two to five germ-
cells (Fig. 7), while the middle and posterior portions rarely
contain more than one or two germ-cells (Fig. 8). Sections
through the posterior region of a genital ridge frequently con-
tain only the peritoneal cells (Fig. 9) which seem to be
crowding into the germinal area in increasing numbers at this
time.

The primordial germ-cells in the sex-gland of a tadpole
about to undergo metamorphosis are similar to those found
in the genital ridge at the stage of Fig. 4, except that they
contain only a small amount of yolk. After the greater
part of the yolk has been absorbed there is found in the cyto-
plasm of these cells a small, round, deeply staining, apparently
homogeneous body which is sometimes, though not invariably,
surrounded by a clear area (Fig. 8, V). This body, which I
shall call the vitelline body, divides previous to the cell mitosis
(Fig. 7, V), and one of these bodies is to be found subse-
quently in each of the daughter cells.

In addition to the vitelline body, there is found in the

No. 2.] THE OOGENESIS OF BUFO LENTIGINOSUS. 377

cytoplasm of the germ-cells, usually close to the nucleus, a
small centrosome which is surrounded by a rounded, granular
attraction-sphere (Fig. 8, C). This centrosome divides very
early in preparation for the cell mitosis, and, as shown in Fig.
7, it is sometimes possible to find a section of a cell which con-
tains two centrosomes as well as two vitelline bodies. Such
a section shows conclusively that the vitelline body is not de-
rived from the centrosome and that there is no relation be-
tween these bodies. I have, as yet, no clue to the origin of
the vitelline body which, as will be shown later, is undoubt-
edly concerned in the formation of yolk nuclei. A structure
similar to the vitelline body is found in the cytoplasm of the
spermatogonia of Bufo, and it can be traced directly to the
spermatids where it gives rise to the acrosome of the mature
spermatozoon. Since Meves (69), McGregor (63), and Bro-
man (13) have found that the acrosome of the amphibian sper-
matozoon is derived from the idiozome, I suggested in a
previous paper (King, 52) that the body in Bufo which forms
the acrosome might possibly be derived “from a condensation
of a portion of the attraction-sphere at an early period in the
history of the primary spermatogonia.” My study of the
primordial germ-cells has not given any support to this hy-
pothesis since, although this body is usually found near the
attraction-sphere (Fig. 7), the two structures are clearly dis-
tinct at all times and there is not the slightest evidence that
the former is derived from the latter. In its size and general
appearance the vitelline body closely resembles the small
nucleoli in the nuclei of the primordial germ-cells, but I have
seen nothing that would indicate that it is of nucleolar origin.
The later history of this structure in the ova strongly suggests
that it is a secretion product of the cytoplasm formed, pos-
sibly under the influence of the nucleus, but not from nuclear
material.

According to the investigations of Bouin, the increase in the
number of germ-cells in Rana is brought about through a con-
tinuous process of transformation of peritoneal and mesen-
chyme cells into sex-cells, not by mitosis nor by direct division

378 KING. [Vou. XIX.

of the germ-cells already present in the germinal area. In
Bufo I have found that the multiplication of the germ-cells
is solely through mitotic division of the primordial cells
evolved from embryonic issue. Although mitotic figures are
comparatively rare during the early stages of development
they are found very abundantly when the tadpole approaches
metamorphosis, and in a single section of the ovary of a toad
killed at this time one may find several cells that are preparing
to divide (Fig. 17, P). Stages in the division of the primor-
dial germ-cells are shown in Figs. 10-14. In the early pro-
phase of mitosis the chromatin forms a thick spireme which is
so much convoluted that it is impossible to determine whether
it is continuous or not. This spireme is subsequently broken
into segments of various lengths (Fig. 10). There are 24
of these segments, this being the number that is characteristic
of the somatic cells of the species. Usually all of the nucleoli
have disappeared before the segments are formed, but some-
times, as shown in Fig. to, Nu., a nucleolus will persist until
a much later period. This would seem to indicate that the
nucleoli are not used in the formation of the chromosomes.
The chromatin segments shorten gradually and form broad,
V-shaped loops which can readily be arranged in pairs ac-
cording to their lengths (Figs. a1, 12). In the metaphase
the chromosomes are arranged in a circle with the angle of
the V turned towards'the centre of the spindle (Figs. 11, 13,
15); and, as they subsequently undergo a longitudital divi-
sion, much narrower V-shaped chromosomes are found at the
spindle poles in the late anaphase (Fig. 14).

In sections of the ovary of a tadpole killed at the time of
metamorphosis germ-cells are frequently found which appear
to contain two or more separate nuclei (Figs. 15, 16, X).
Judging from these figures alone one might feel justified in
concluding that the germ-cells divide amitotically as well as
by mitosis. I have never found a division of the cytoplasm
in any of the cases in which sections of the germ-cells contain
two or three nuclei, and in every instance the following or
preceding sections invariably show a connection between the
various unclei in the cell. It is evidentfi therefore, that the

No. 2.] THE OOGENESIS OF BUFO LENTIGINOSUS. 379

apparently multinucleated cells are not preparing to divide by
amitosis. Their appearance is doubtless due to the fact that
in sectioning the cells the polymorphic nuclei were cut in such
a way as to completely separate two or more lobes. In my
study of the germ-cells of Bufo I have never found a single
instance where I could be sure that a cell was dividing amitoti-
cally; and I am convinced that this mode of division does not
normally occur in any of the germ-cells of the ovary or of the
testis.

By the time that a tadpole is sixteen to eighteen days old
the anterior portion of each genital ridge has developed into
a small rounded body, the so-called “Bidder’s organ.” The
structure and development of this organ will form the subject
of a separate paper and therefore no further mention of it
will be made here, as it has seemingly nothing to do with the
development of the ova.

Although sex is doubtless determined at a very early stage
of development, the germ-cells of Bufo remain in an apparently
indifferent condition for a long period, and it is not until
the tadpole is about to undergo metamorphosis that its sex
can be ascertained with any degree of certainty. Several
investigators of amphibian odgenesis have stated that the
presence of a central cavity in the genital ridge is the first
characteristic by which the young ovary can be identified. In
Bufo it is possible to distinguish the sexes at a somewhat
earlier period of development by means of the arrangement
of the cells in the more anterior portion of the sex-gland. In
the young male the germ-cells are scattered evenly through-
out the testis, each being surrounded by a number of follicle
cells; in the young female the germ-cells have a definite ar-
rangement around the outside of the ovary, while the centre
is filled with peritoneal cells (Fig. 15). There -is no central
cavity in any part of the genital ridge at this time.

When the genital ridge has taken on the definite character
of an ovary, some of the odgonia still contain a few small yolk
spherules (Fig. 15), although all traces of yolk have long
since disappeared from the other cells of the body. There is
no ovarian wall at this time and the odgonia are surrounded

380 KING. [Vor. XIX.

by follicle cells as in an earlier period. At a slightly later
stage of development (Fig. 16), the central part of the ovary
is no longer completely filled with peritoneal cells, but it con-
tains a number of intercellular spaces which later unite to form
one large cavity (Fig. 17). The central cavity in the ovary
of Bufo is not, therefore, a portion of the general body-cavity
which is brought into the ovary by a fold of peritoneal epithe-
lium as Hoffman has claimed is the case in Triton and in
various other amphibians, but it is the result of a fusion of
the many intercellular spaces which-are produced by the rapid
increase in the size of the ovary. In Fig. 16 is shown the
beginning of the formation of the outer ovarian wall. At
the upper part of the ovary a number of peritoneal cells are
found with their nuclei flattened against the outer surface of
the germ-cells. The outlines of these cells become obliterated
and their cytoplasm forms a continuous layer over the
oogonia. At a slightly later stage (Fig. 17), many of the
peritoneal cells in the interior of the ovary become arranged
along the inner side of the oogonia to form the inner wall
of the ovary. In the young female as well as in the adult,
the ova develop between the two ovarian walls.

The small cells with deeply staining nuclei which are so
conspicuous in the ovary at the stages of Figs. 15-17 have
been called by various observers mesenchyme cells, peritoneal
cells, and follicle cells; while Bouin considers them to be
“petites cellules germinatives.”” In Bufo these cells are found
with the primordial germ-cells when the latter are first sepa-
rated from the endoderm at the stage of Fig. 3, and from their
general characteristics they are doubtless to be classed as
mesodermal cells. Occasionally these cells are found dividing
mitotically (Fig. 15, R); but division figures in them are
rare as compared with those that are found in the germ-cells.
The number of these cells increases enormously as the ovary
enlarges; and, since there is no evidence that they divide
amitotically, it is probable that there is a continuous migration
of cells from the mesentery through the ovary pedicle into
the ovary. Many of these cells later become the follicle cells
which are found-around the egg as long as it remains in the

No. 2.] THE OOGENESIS OF BUFO LENTIGINOSUS. SOE

ovary; the others, as far as I can determine, are actively
concerned in the formation of the ovarian walls, the cyst
membranes and the zona pellucida.

According to the observations of Bouin there are fewer
primordial germ-cells in a tadpole of Rana temporaria that
is 33 mm. long than in one 20 mm. long. As the difference
in numbers is considered too great to be attributed to indi-
vidual variation, Bouin believes that a reduction in the num-
ber of primordial germ-cells is brought about at this stage of
development through an expulsion of a large number of these
cells from the ovary into the body-cavity. He calls this pro-
cess “ponte d’ovules primordiaux,” and he considers that it
is analogous to that which occurs in the adult frog when the
ripe eggs are expelled from the ovary. Bouin suggests that
this process may take place so that “‘la glande, qui évolue dans
le sens male, élimine les éléments qui seraient inutiles a son
développement ultérieur.” None of the other investigators
who have worked on the development of the sex-glands in
amphibians have described such a reduction in the number
of primordial germ-cells and there is nothing similar to it
to be found in Bufo. The expulsion of primordial germ-cells
from the ovary is, therefore, either a process that is peculiar
to Rana temporaria, or it is one which takes place so quickly
in other species that it has escaped the attention of the in-
vestigators working in this field.

As the tadpole approaches metamorphosis, the ovary in-
creases in size very rapidly and it usually appears lobed when
examined in toto under a low power of the microscope. This
lobed appearance of the young ovary furnishes a means by
which it can be distinguished from the testis without making
use of sections.

Ill. THe SECONDARY OOGONIA.

Soon after metamorphosis the primary odgonia give rise to
a new generation of cells, the secondary odgonia, which are
aggregated into cysts or “cell nests” that are arranged much

382 KING. [Vou. XIX.

as are the primary oogonia shown in Fig. 17. The cells of a
cyst are all descendants of one primary oogonium, and the
cyst wall is formed evidently by the follicle cells which had
previously surrounded the parent cell. The secondary oogonia
are somewhat smaller than the primary oogonia, but they
closely resemble them otherwise. They have a polymorphic
nucleus containing a faintly staining reticulum and several
plasmosomes. In the cytoplasm is a vitelline body (Fig. 18,
VY) and also a minute centrosome surrounded by a granular
attraction-sphere (Fig. 18, C).

The cells of a cyst do not always divide simultaneously, and
resting cells as well as cells in all stages of division may be
found in the same cyst (Fig. 19). In the early prophase of
mitosis a thick spireme is formed, as in the primary oogonia.
This spireme breaks into segments (Fig. 19, S), presumably
twenty-four, which condense into V-shaped chromosomes in
the metaphase (Fig. 19, O). The spindle is the same shape
as that found in the earlier generations of cells, and there are
distinct centrosomes at the spindle poles which are devoid of
any radiation (Fig. 19, O, R).

IV. THE DEVELOPMENT OF THE OOCYTES TO THE
SyYNIZESIS STAGE.

Considerable controversy has arisen among investigators
regarding the origin of the odcytes in the amphibian ovary
since, at the period of the transformation of oogonia into
oocytes, cell and nuclear boundaries are frequently obscured
and the cyst contents appear as a syncytium.

In his classic work on Bombinator igneus, Goette (35)
states that in the young ovary the protoplasmic bodies of the
central cells of a cyst fuse into a single mass which contains
at first several separate nuclei; later the nuclei also fuse to
form the mulberry shaped germinal vesicle of the egg. This
view has been slightly modified by Bataillon (6), who con-
cludes, from his observations on Rana and on Bufo, that after
the fusion of the cytoplasmic bodies of the cells of a cyst one

No. 2.] THE OOGENESIS OF BUFO LENTIGINOSUS. 383

of the nuclei wins the upper hand and subsequently absorbs
all of the others.

Gemmil’s (34) observations seem to indicate that “in der
Regel geht aus einem Zellnest nur ein Ei hervor, und zwar
durch directe Entwickelung aus einem der Elemente des Zell-
nestes. Won den iibrigen Elementen bilden sich einige wieder
zurtick und betheiligen sich an der Bildung der Granulosa,
der Rest aber geht zu Grunde.” According to Gemmil,
there appears to be a struggle among the cells as to which
shall form the ovum; space being the chief factor which de-
cides the contest. The cell which lies in the centre of a cyst
has seemingly the most room for development and this is the
one which usually wins. The fate of the other cells depends
upon how far they have differentiated before the one cell be-
comes the ovum and so governs the rest. The cells which are
least differentiated assume the rdle of granulosa cells. Those
further developed cannot go backwards; they either have to
become eggs or disintegrate. If the cyst happens to be larger
than usual, as many as four of the cells may have room to
develop into functional eggs. Since extra space is rarely ob-
tained by the cyst, all of the cells which have passed a certain
stage of development before the egg has formed are, as a
rule, forced to disintegrate, and traces of the débris from these
cells are to be found for some time in the protoplasm of the
developing egg. Hoffmann’s opinion regarding the origin
of the egg in the Anura is similar to that of Gemmil, since
he believes that one cell of a nest outstrips the others in
development and forms the ovum while the others degenerate
and become granulosa cells. Semon’s observations lead to
a similar conclusion.

Nussbaum and also Knappe (54) find a mulberry shaped
nucleus in the primordial germ-cells, and they assert that
this nucleus divides by amitosis into several small nuclei. One
of these nuclei increases rapidly in size and becomes sur-
rounded by the greater part of the cytoplasm of the cell, thus
forming the egg; the other nuclei become arranged around
the periphery of the egg to form the follicle epithelium. Ac-

384 KING. [Vort. XIX,

cording to Eismond (27) an ovum may arise either from one
of the cells of a nest which has outstripped the others in
development, or from a fusion of all of the cells of a cyst. He
also considers that “‘la formation des nids n’était pas un anneau
indispensable dans le cycle de l’oogenése, c’est-a-dire qu’en
méme temps que la formation des nids du sens strict, se faisait
aussi la différenciation progressive des oocytes directement
aux dépens des produits de la derniere division des odgonies,
comme cellules independantes.”’ The conclusion that ova may
arise directly from oogonia accords with the view advanced in
1870 by Waldeyer (91) and supported later by the researches
of Balfour (4) on elasmobranchs.

Bouin has investigated the formation of the ova in much
greater detail than have any of the other workers on amphibian
oogenesis. He finds, as do other investigators, that secondary
oogonia are enclosed in cysts, and he states that all of the
oogonia in a cyst divide simultaneously. After several
divisions, the number of which he does not determine, the
character of the cells changes considerably and “oogonia of
transition” are formed. ‘The latter are clearly defined cells
with rounded nuclei in which there are several chromatin
nucleoli, but no traces of a chromatin reticulum. This stage
is succeeded by one in which the nuclear membrane disap-
pears and the karyoplasm is separated from the cytoplasm
only by clear area. At a later stage of development granular
threads appear in the nucleus which are formed, doubtless, of
the minute chromatin granules scattered in the karyoplasm.
These threads increase in number very rapidly and form a
distinct chromatin reticulum, while a new nuclear membrane
encloses the nuclear contents. All the cells of a cyst develop
up to this stage, but later, owing to some unknown causes,
only a part of the cells continue their development as oocytes ;
the others degenerate and are either dissolved gradually or
devoured by the phagocytes. Degenerating cells never form
follicle cells but probably serve as nutriment for the victori-
ous oocytes. The results of Bouin’s investigations agree es-
sentially with those reached by Balfour in his study of

No. 2.] THE OOGENESIS OF BUFO LENTIGINOSUS. 385

elasmobranchs. The latter investigator states that “some of
the nuclei of each nest are converted into the nuclei of the
permanent ova, others break down and are used as the pabulum
at the expense of which the protoplasm of the young ovum
grows.”

Judging from the number of cells in a fully formed cyst,
there are at most four or five generations of secondary oogonia
in the ovary of Bufo. After the last odgonial division resting
nuclei are formed, and the cyst is filled with small cells which
appear much like that shown in Fig. 20. At this time cell
and nuclear boundaries are very much more indistinct than
in earlier stages, yet they can readily be made out in prep-
arations fixed in Flemming’s solution and stained with iron
hematoxylin. If the material is properly preserved the cells
never form a syncytium; nor is there any fusion of the nuclei,
or any absorption by one nucleus of its less fortunate neigh-
bors. Each cell in a cyst develops into an oocyte, and, al-
though I have examined a large number of cysts in this stage
of development taken from many different individuals, I have
yet to find a single instance in which there is a degeneration
of any of the germ-cells in a cyst or any change of germ-cells
into follicle cells. It seems very probable that the cells which
several investigators have considered to be degenerating young
oocytes, were, in reality, cells in which the nuclei were in
the condition shown in Fig. 25. This contracted state of the
nuclear contents, to which McClung (62) has applied the
term synizesis, is a definite constructive stage in the develop-
ment of the young oocyte of Bufo, and it is not due in any
way to a degeneration of the nucleus or of the cell.

Owing to the crowded condition of the cells in a cyst the
young o6cyte is more or less polygonal in outline. The nucleus
is very large in proportion to the size of the cell, and it is
invariably oval or slightly irregular, never possessing the
polymorphic form characteristic of the nuclei in the earlier
generations of cells. At this period the chromatin shows little
capacity for staining and, as in the resting odgonia, it is in
the form of minute granules which are either scattered along

386 ; KING. [VoL. XIX.

the nuclear membrane or distributed on the linin fibres which
form an irregular reticulum. The nucleus contains several
deeply staining nucleoli of various sizes which are suspended
in the meshwork of the reticulum or held against the nuclear
membrane. In preparations stained with safranin and gen-
tian violet the larger nucleoli invariably take the safranin
while the rest of the nucleus is stained blue with the gentian
violet, and these bodies must, therefore, be considered as
plasmosomes; the very small nucleoli, which are found chiefly
at the points of intersection of the linin threads, are karyo-
somes since they take the chromatin stain. In the cytoplasm,
which stains very faintly and appears somewhat reticular,
there is a vitelline body (Fig. 20, V); but I have not been
able to find any traces of a centrosome or of an attraction-
sphere in this or in any later period in the development of the
oocyte. As there are no centrosomes at the poles of the ma-
turation spindle (King, 51), it seems probable that the egg
centrosome disappears after the last oogonal division and that
the attraction-spheres found at the poles of the segmentation
spindle are formed in conjunction with the sperm-nucleus,
probably under the influence of the centrosome imbedded in
the substance of the sperm-head.

As the odcyte enlarges its outline becomes more regular and
much more distinct. The nucleus, which measures about 0.0!
mm. in diameter at this time, soon assumes the rounded form
which it retains up to the maturation period (Fig. 21), and
its reticulum appears continuous and much more sharply de-
fined than at an earlier period (Fig. 22). The number of
nucleoli is not appreciably increased during the early growth
period of the oocyte.

V. SYNIZEsSIS AND Post-SYNIZESIS STAGES.

Although the stage in the development of the oocyte shown
in Fig. 22 is practically at the beginning of the growth
period it corresponds, apparently, to the stage at the end of the
growth period of the spermatocyte (King, 52; Fig. 15). In

No. 2.] THE OOGENESIS OF BUFO LENTIGINOSUS. 387

both cases the nucleus contains a granular reticulum which
appears to be continuous; and in both oocyte and spermatocyte
this stage is followed immediately by one in which there is
a gradual condensation of the nuclear contents leading to
synizesis (Fig. 25). The beginning of the process of con-
densation in the odcyte is shown in Fig. 23, where the greater
part of the chromatin reticulum is seen to be collected in the
centre of the nucleus. In the following stage the contraction
of the nuclear reticulum becomes more marked (Fig. 24),
and eventually all of the nuclear contents forms a more or
less rounded mass in the centre or at one side of the nucleus
(Fig. 25). In favorable preparations the contraction figure
is found to be composed of a tangled mass of exceedingly fine
filaments in the meshes of which there are several round,
apparently homogeneous bodies which are doubtless the plas-
mosomes: a number of the filaments run out from the central
body and connect this structure to the nuclear membrane.
At this stage it is impossible to follow in detail the changes
that are taking place in the nucleus or to determine what
relation the fine filaments bear to the nuclear reticulum of the
earlier stage. The condensation of the nuclear contents in
synizesis is not carried quite as far in the ooyctes of Bufo as it
is in the spermatocytes where the contraction figure frequently
appears as a rounded, apparently homogeneous mass con-
nected by a few fine filaments to the nuclear wall (King, 52;
Figs. 20-22).

In toads killed at the time of metamorphosis the ovaries con-
tain large numbers of secondary oogonia and young oocytes,
although only a few of the latter have reached the synizesis
stage at this time. Contraction figures are frequently met with .
in the ovaries of young toads killed about four weeks after
their metamorphosis, and they are found very abundantly
afterwards until the toad has attained a body length of about
1.5 cm. As I have already pointed out in the case of the
spermatocytes of Bufo, I do not think it possible that the con-
traction figures are due to a bad preservation of the material
as Janssens (47) has asserted is the case in Batracoseps atten-

388 KING. [Vor. XIX.

uatus, since oocytes with their nuclei in synizesis are found in —
all parts of the ovary and frequently lie adjacent to oocytes in
which the chromatin is in the form of a clearly defined con-
tinuous spireme (Fig. 22). Any method of fixation that
would cause such a decided distortion of the nuclear contents
in the one cell must of necessity have some effect on a neigh-
boring cell which is in but a slightly different stage of develop-
ment. In Bufo synizesis is not due to the degeneration of
certain cells as Kingsbury (53) has claimed is the case in
Desmagnathus fusca, since only in very rare instances are de-
generating eggs to be found in the ovaries of young toads.
Degenerating eggs, whether they are found in the ovaries of
young toads or in those of adults, are usually deeply pigmented
and they are invariably filled with phagocytes; they never
resemble in any way the oocytes shown in Figs. 24-25.

Synizesis, which is a well recognized stage in the develop-
ment of the odcytes and spermatocytes of many forms, has,
for the most part, been ignored by the investigators who have
worked on the germ-cells of amphibians, or its presence has
been considered as evidence of a degeneration of the cell.
Gemmil describes a stage in Pelobates fuscus in which the
nucleus of the young odcyte contains a star-shaped mass of
chromatin which lies in the middle of a clear area and sends
out processes to the nuclear membrane. It is evident, from
the figures which Gemmil gives, that synizesis is the normal
stage in the development of the ova of this amphibian. Nuss-
baum figures condensation stages in the young germ-cells of
Rana fusca when they are enclosed in a cyst membrane. He
has, however, mistaken the order of sequence in the develop-
. ment of the cells, as he considers that the contraction stage
preceded one in which the cell contains a mulberry-shaped
nucleus. Bataillon, Leydig, and Hoffman also mention the
appearance of contracting figures in the course of the normal
development of amphibian ova, although they venture no opin-
ion as to the significance of these bodies.

Bouin has entirely overlooked in Rana temporaria the young
oocytes shown in my Figs. 20-22, and the earliest stage that he

No. 2.] THE OOGENESIS OF BUFO LENTIGINOSUS. 3890

figures as an oocyte (Plate XII; Fig. 6), is about like that
of my Fig. 39. He does not believe that synizesis is a nor-
mal stage in the development of the odcytes of Rana, although
he figures contraction stages of the nuclei in cells which he
considers as o6gonia that are not able to develop into oocytes.
His description of the nucleus of one of these “degenerating”
cells is as follows: “On constate que les microsomes constitutifs
du réticulum chromatique se gonfluent, se soudent les uns aux
autres, forment des amas irréguliers qui se colorent comme
les chromosomes des noyaux en mitose. Ces amas peuvent
rester isolés dans l’aire nucléaire ou s’amalgamer en un bloc
chromatique de faibles dimensions.”’ The one figure which
Bouin gives of such nucleus (Plate XI; Fig. 15), shows the
synizesis stage in Rana which corresponds closely to that in
Bufo shown in Fig. 25; and many of his other figures show
post-synizesis stages comparable to those in Bufo (Plate XI;
Figs. 10, 11: Plate XII; Figs. 2-5).

In a recent paper Lams (57) has given a description of the
stages in the early development of the oocytes of Rana tempo-
raria which were overlooked by Bouin. According to this
investigator the nuclear membrane does not disappear at any
time during the transition of the oogonia into the oocytes. In
the young odcytes the chromatin filaments gradually condense
at one pole of the nucleus until they form a rounded, deeply
staining mass which appears much like that shown in my Fig.
25. In post-synizesis stages this contracted mass resolves into
a system of filaments which subsequently divide longitudinally
and scatter throughout the nucleus. This work of Lams, with
that of Bataillon and Leydig, furnishes conclusive evidence
that synizesis is a normal stage in the development of the
oocytes of Rana.

It is unfortunate that the contracted condition of the nuclear
contents during synizesis prevents a detailed study of the
changes taking place in the chromatin at this time. It is
evident that during synizesis the nuclear reticulum is no longer
continuous, and that it becomes broken up into a large number
of exceedingly fine filaments. Some of these filaments appear

390 KING. [Vou XIX.

to be composed of a series of minute granules; others of
delicate linin threads. As the plasmosomes can still be found
during synizesis it is probable that they play no part in the
changes taking place in the chromatin.

From the contraction figure shown in Fig. 25 there is
evolved a long, apparently continuous, much convoluted
spireme which is made up of a series of deeply staining chro-
matin granules distributed on a linin thread (Fig. 26). In the
meshes of this spireme there are several nucleoli of various
sizes, and there are also from one to five irregularly shaped,
apparently homogeneous nuclear masses which are distributed
along the nuclear membrane. These masses all stain intensely
black with iron hematoxylin as does also the spireme. If,
however, preparations have been satisfactorily stained with
safranin and gentian violet the spireme is deep blue, the very
small nucleoli appear red, while the large nucleoli and the
masses against the nuclear membrane are purple, thus indicat-
ing that they are composite structures although they usually
appear homogeneous at this time.

From the stage shown in Fig. 21 to that of Fig. 26 the
oocytes do not grow to any appreciable extent and the nuclei
measure from 0.011-0.013 mm. in diameter. After synizesis
there is a rapid increase in the amount of cytoplasm and in
the size of the nucleus (Fig. 27). The chromatin spireme be-
comes more evenly distributed throughout the nuclear space,
and it is noticeably thicker than at the stage of Fig. 26. In
the succeeding stage the spireme begins to split longitudinally
(Fig. 28). As the sister portions of the spireme are only about
one-half of the thickness of the spireme at the stage of Fig.
27 it is evident that there is a true longitudinal division of the
spireme at this time and not a folding together of chromatin
filaments similar to that which occurs in the young odcytes of
the rabbit according to the investigations of von Winiwarter
(93). At the stage of Fig. 29 the greater part of the spireme
has divided and many of the sister threads have separated a
considerable distance. When the splitting of the spireme has
been completed the sister threads lie parallel, for the most

No. 2] THE OOGENESIS OF BUFO LENTIGINOSUS. 301

part, although they are not connected in any way. The threads
do not present the clear cut, granular appearance of the
spireme shown in Fig. 26, as they have a jagged outline and
send out fine projections on either side.

There is absolutely no uniformity in the arrangement of the
chromatin threads after the splitting of the spireme. At times
the sister threads seem to lie close together throughout their
whole extent (Fig. 30) ; again the sister portions of the spireme
lie parallel for a short distance and then become widely scat-
tered throughout the nucleus (Fig. 31); in rare cases, as
shown in Fig. 32, the chromatin threads are as evenly dis-
tributed throughout the nucleus as they are at the stage shown
in Fig. 27, and there is nothing except the size of the nucleus
and the character of the threads to indicate that there has
been a splitting of the spireme. I am very sure that such a
condition-of the chromatin as that shown in Fig. 32 could
not have been brought about by a gradual lengthening of the
spireme, since the great majority of nuclei intermediate in
size between that of Fig. 27 and that of Fig. 32 appear similar
to those shown in Figs. 28-31.

Soon after the stage of Fig. 30 the spireme breaks trans-
versely, forming, in most cases, long double segments which
vary considerably in length (Figs. 33, 34, 36, 37). The sister
portions of the segments may lie parallel or they may be
intertwined in various ways; they may be united at one or at
both ends, forming a figure 8 or an oval ring; in other cases
both ends of the segments are free and the threads cross in
the form of an X or a Y. The condition of the chromatin
threads shown in Figs. 30-34 is found in nuclei having a
diameter of 0.015-0.02 mm.

I have tried to reconstruct a nucleus in the stage of devel-
opment shown in Figs. 33-34, by placing together a series of
camera drawings of all of the sections of the nucleus, in the
hope that I might be able to determine by this means the total
number of chromatin segments. Owing to the fact that the
segments are of different lengths and that they are united in a
great variety of ways, it has been very difficult to arrive at any

302 KING. [Vov. XIX.

exact conclusion regarding their number. I believe, however,
that the nucleus at this stage contains only the somatic number
of chromosomes (24) which are usually arranged in twelve
pairs. The question at once arises as to the value of the sister
segments which form a pair. Is the splitting of the spireme
shown in Figs. 28-30 a longitudinal division of chromosomes
united end to end in the spireme or is it a separation of uni-
valent chromosomes which had conjugated side by side? This
question is very difficult to answer since it is impossible to de-
termine what changes the chromatin undergoes during syn-
izesis. As the nucleus apparently contains but twenty-four
chromatin segments which in later stages of development are
scattered throughout the nucleus and only occasionally found
in pairs, I am inclined to the opinion that each .of the sister
segments represents an odgonial chromosome. The paired
arrangement of the chromosomes at the stage of Figs. 33-34
strongly suggests that in the odcytes of Bufo synapsis is co-
incident with synizesis as it is apparently in the spermatocytes ;
yet for various reasons, which will be given later, I am inclined
to consider that synapsis does not occur until the beginning of
the maturation period.

At the stage of Figs. 20-21 all of the young oocytes in a
cyst are approximately of the same size and in practically the
same stage of development. As the synizesis period approaches
the oocyte which lies nearest the cavity of the ovary grows
very rapidly and soon becomes several times the size of its
neighbors. <A section of a cyst with the odcytes in this con-
dition is shown in Fig. 37. The large cell bordering the
cavity of the ovary has a diameter of 0.043 mm., and its
nucleus measures 0.023 mm. in diameter. This odcyte is sur-
rounded by a number of follicle cells and its nucleus contains
paired chromatin threads. The other cells in the cyst are very
nearly of the same size; each measuring about 0.015 mm. in
diameter and containing a nucleus measuring 0.01 mm. in
diameter. These smaller odcytes are in early post-synizesis.
stages of development, and they are not degenerating, as sev-
eral investigators who have found a similar condition of the

No. 2.] THE OOGENESIS OF BUFO LENTIGINOSUS. 303

cells of a cyst have claimed. The development of these cells
is slower than that of the one cell simply because the size of
the cyst is limited and there is no space for a more rapid
growth.

Soon after the stage shown in Fig. 37 the cyst wall is rup-
tured, owing doubtless to the pressure of the growing oocytes,
and the larger cell becomes separated from the rest of the cyst
and surrounded by a membrane which attaches it to the wall
of the ovary. Inside of this membrane there are always found
a number of elongated follicle cells which are undoubtedly
concerned in the formation of the zona pellucida which later
develops around the egg (Figs. 36, 39). As the other cells
of the cyst enlarge each in turn becomes similarly attached to
the ovarian wall. The cysts do not all develop at the same
rate. In the ovaries of toads with a body length of 1.5 cm.
one may find some cysts containing odgonia, others filled with
young odcytes in various stages of development up to that
shown in Fig. 37, while in many cases the cysts have become
disorganized and the ova are separately attached to the ovarian
wall.

VI. THr NUCLEOLI AND THE LATER GROWTH STAGES OF
THE OOCYTES.

The irregular shaped masses of nuclear substance found
against the nuclear membrane or in the meshes of the chro-
matin reticulum at the stage of Fig. 26 seem to increase in
size as the nucleus grows and one of them usually becomes
much larger than any of the others. These bodies appear
homogeneous and stain black with iron hematoxylin or
purple when the preparation is stained with safranin and gen-
tian violet. When the nucleus has attained a diameter of about
0.025 mm. and the splitting of the spireme has been com-
pleted, numerous fine granular fibres are seen to project from
these masses which do not stain quite as intensely as before
(Fig. 34). At the next stage (Fig. 35) one obtains the first
clue to the structure of these bodies. With the use of iron

304 KING. [VoL. XIX.

hematoxylin the masses now appear grayish, and they are
found to be composed of a meshwork of exceedingly fine
fibres inclosing several darker homogeneous bodies. In prep-
arations stained with safranin and gentian violet a much bet-
ter differentiation is obtained. The meshwork of fibres in-
variably takes the blue of the gentian violet, while the rounded
bodies in the interior, which are of various sizes, react differ-
ently towards the stain; the larger of these bodies, which are
usually slightly irregular in outline, stain a reddish purple;
the medium-sized ones, which are rounded and have a smooth
outline, stain uniformly red, while the very small granules take
the gentian violet. From the staining reactions of these
masses, therefore, it is evident that they contain two different
substances ; fine fibres which are doubtless composed of chro-
matin not used for the chromosomes, and rounded bodies which
are nucleoli.

For convenience in description I shall apply the term com-
pound-nucleoli to the complex masses shown in Figs. 26-35
and also to the irregular nucleolar bodies shown in Figs. 39,
40, 43, 45, etc., reserving the term nucleoli for the smaller
rounded bodies found in the interior of the larger masses at the
stage of Figs. 35-36. The nucleoli which stain uniformly red
with safranin will be called plasmosomes, while those that stain
like chromatin will be considered karyosomes. In order to
distinguish the chromatin of the chromosomes from that of
the meshwork which forms part of the compound-nucleoli I
shall refer to the former as “‘basichromatin” and to the latter
as “oxychromatin.” Iam aware that these terms are not being
used strictly in the sense in which they were introduced by
Heidenhain (37), since both kinds of chromatin show the
same color reactions with all methods of staining employed.
Their use has been considered advisable here, however, in
order to avoid the introduction of new terms.

At the stage in the resolution of a large compound-nucleolus
shown in Fig. 36, the oxychromatin meshwork is much more
clearly defined than at an earlier period and ‘the threads are
thicker and more granular. The number of nucleoli found in

No. 2.] THE OOGENESIS OF BUFO LENTIGINOSUS. 395

the nucleus at this time greatly exceeds that found at any
previous stage in the development of the oocyte, and it 1s evi-
dent that a new formation of these bodies must take place dur-
ing or soon after the synizesis stage. The compound-nucleoli
in a nucleus do not resolve simultaneously. The larger masses
are always the first to break up, and one or two of the smaller
bodies may remain unchanged until the nucleus is twice the
size of that shown in Fig. 36. Soon after the stage of Fig.

36 the meshwork of fibres becomes very loose and frequently
breaks into several parts, while the nucleolar bodies begin to
leave the fibres and scatter about the nucleus (Fig. 38). At
the stage of Fig. 39 the resolution of the largest compound-
nucleolus has been completed and the nucleus contains a num-
ber of nucleolar bodies of various sizes as well as several
masses of tangled oxychromatin threads which are entirely
separated from the nucleoli and easily distinguished from the
chromosomes.

_ Inhis Fig. 15, Bataillon shows a portion of the nuclear con-
tents of an ovarian egg of Rana which is very similar to one
of the larger resolving masses shown in my Fig. 38. Bataillon
believes that his figure shows the beginning of a connection
between the chromatin filaments and the nucleoli, and he states
that later the filaments disappear entirely, all of their substance
going into the uncleoli. These results dg not accord with what
I have found in Bufo, since in the oocytes of this amphibian
the nucleolar bodies are preparing to leave the chromatin
meshwork at the stage of Fig. 38, and chromatin filaments are
to be found in all of the later growth stages of the ova.

At the stage of Figs. 33-34, the chromosomes stain some-
what more faintly than at an earlier period, and they are com-
posed of a series of minute granules from which numerous
fine fibres extend out a short distance on either side. In later
stages these side projections become much more numerous
and somewhat longer, and the chromosomes then come to have
the feathery appearance shown in Fig. 39. At a later period
the chromosomes stain so very faintly that in many cases they
are to be found only with the aid of an immersion lens, yet

306 KING. [Vou. XIX.

they retain the characteristic structure shown in Figs. 39, 40,
43, etc., and are therefore always to be distinguished from the
oxychromatin threads. The chromosomes are never united
with the nucleoli, although sometimes, as shown in Figs. 36,

7 and 39, a nucleolus is in contact with a chromatin thread ;
neither is there any connection between the basichromatin fila-
ments and the oxychromatin threads. The latter stain much
more intensely than the former and always appear to be com-
posed of a series of rounded granules, they never have the
feathery structure of the chromosomes. After the stage of
Figs. 33-36, the chromosomes become widely distributed
throughout the nucleus, and only a very few of them are
found paired in later stages of development.

In a preliminary paper on the oogenesis of Triton, Janssens
(46) gives a brief account of the changes taking place in the
young odcytes which seems to show that the behavior of the
chromatin in the eggs of this amphibian is somewhat different
from that I have found in Bufo. Janssens finds that synizesis
occurs during the early growth period of the oocyte, but he
states that the reduced number of chromatin filaments appears
shortly after this stage and that these filaments subsequently
split longitudinally, the sister threads always remaining to-
gether in later development.

Carnoy and Lebrun (15-18; Lebrun, 58, 59) have written
an elaborate series of memoirs dealing with the germinal vesicle
and the polar bodies in various species of Batrachians. They
have not studied the primordial germ-cells or the early growth
stages of the oocytes, and in every case their investigations be-
gin with the young ovum at a stage about like that of my Fig.
27. Although the details of the developmental processes in
the ova differ somewhat in the various species, Carnoy and
Lebrun invariably find that, in the earliest stage which they
have studied, the nucleus contains a chromatin filament which
seems to be continuous. Later this filament disintegrates and
gives rise to “primitive nucleoli” which move to the centre of
the nucleus and there resolve into chromatin threads of vari-
ous types. These chromatin threads soon break up into minute

No. 2.] THE OOGENESIS OF BUFO LENTIGINOSUS. 397

granules from which new nucleoli develop to undergo the
same series of changes as their predecessors. When the germ-
inal vesicle disintegrates at the beginning of the maturation
period certain of the nucleoli escape dissolution to form the_
twelve chromosomes which undergo a double longitudinal
division in preparation for the maturation mitoses. At certain
periods during the development of the ova, therefore, the
nucleus contains no chromatin except that found in the nucle-
oli, and there is no “individuality” of the chromosomes or any
reduction in the Weismannian sense during the maturation
divisions. For Carnoy and Lebrun (16) the most important
structures in the nucleus are the nucleoli. “Les nucléoles sont
le chef-d’ceuvre du noyau: ils représent le degré le plus élevé
de organisation nucléinienne.”’ In another paper (15) the
statement is made that “les nucléoles sont des noyaux en mini-
ature. Il renferme toujours un appareil nucléinien filamenteux
plongé dans un plasma et logé dans une coque mince.”

Carnoy and Lebrun give a large number of figures which
are supposed to furnish evidence in support of their conclu-
sions. They have, however, seemingly overlooked the impor-
tant stages which give the clue to the nature of the “primitive
nucleoli’ and of their relation to the chromosomes (Figs. 28-
39). In many of their figures they show feathery chromo-
somes similar to those shown in my Figs. 39-41, etc.; yet they
consider that these chromosomes are products of the resolu-
tion of the nucleoli, as are also the granular threads which
correspond to my oxychromatin filaments. The feathery chro-
mosomes are often figured in pairs, the sister threads lying par-
allel or intertwined in various ways. Carnoy and Lebrun state
that these paired filaments are not formed by a longitudinal
or by a transverse division of a pre-existent nuclear element,
but that they are either produced by a single filament folding
back on itself and the parts separating, or they are two fila-
ments which have been resolved from two nucleoli lying close
together. Sections of nuclei are given by Carnoy and Lebrun
which contain numerous nucleoli and no chromatin threads.
Such figures are considered to prove conclusively that there

308 KING. [Vou. XIX.

has been no continuation of the primitive filament. It is not
difficult to find sections of the nuclei of the young ova of Bufo,
particularly at the stages of Figs. 40-44, in which no chromo-
somes can be found. Such sections are possible because the
chromosomes, which stain very faintly, are sometimes col-
lected together at one side of the nucleus and sections passing
through the centre of the nucleus show only granular karyo-
plasm, nucleoli, and possibly some of the oxychromatin threads.
After the yolk has formed, many fixing fluids do not seem to
penetrate the egg sufficiently well to preserve the delicate struc-
ture of the chromosomes. I have examined, under an oil im-
mersion lens, every section of the nucleus of an egg preserved
in Gilson’s or Flemming’s solution without finding the slight-
est trace of chromosomes; while in the nuclei of eggs from the
same ovary that were fixed with chromic acetic or corrosive
acetic the feathery chromosomes show very distinctly with
a comparatively low magnification. I have never found a
nucleus in which it was impossible to find the chromosomes,
provided the egg had been properly preserved and stained.

In his earlier work on Axolotl, Fick (28) states that the
nucleoli are independent structures which probably represent
“eine Art Reservestoffbehalter.” In a later paper on the ripen-
ing of the egg of Rana (29) he confirms the work of Carnoy
and Lebrun and states that during the growth period of the
oocyte there are several generations of nucleoli which alternate
with chromatin figures, consequently the continuity of the
chromosomes is not maintained during this time. Fick con-
siders that the nucleoli in the egg of Rana represent “‘eine
Ruheform des Nucleins im Gegensatz zu den Chromatin-
Figuren und Chromosomen, Formen in denen das Nuclein
offenbar eine active Rolle spielt.’’ Carnoy, Lebrun, Fick, and
also Bataillon agree, therefore, with the conclusion reached
many years ago by Schultze (83) from his study of the ripen-
ing of the egg of Rana, that the chromosomes “nicht aus
einem praformirten Kerngeriist entsteht, sondern sich direkt
aus den winzigen Keimkorperchen herausbildet.”’

The observations of other investigators of amphibian

No. 2] THE OOGENESIS OF BUFO LENTIGINOSUS. 309

-_:

oogenesis stand in direct contradiction to those cited above.
Born (9, 10) states that in the egg of Triton the chromatin
skein “sich aus dem Chromatingertist des Ureies direkt her-
leitet.””. Although at one period of development the chromatin
threads stain faintly and the chromatin substance can only
rarely be distinguished from the granular karyoplasm, Born
does not believe that the chromatin disappears or leaves the
nucleus at this time, but that ‘“‘sich dasselbe nur ausserst fein in
der umgebenden Kerngrundsubstanz vertheilt habe.” Later the
chromatin threads are formed again, and they appear in
pairs, lying parallel or closely intertwined as in Bufo. Born
does not find that the nucleoli ever give rise to chromosomes,
and while he ventures no conjecture as td the function of these
bodies he believes that they “stehen in Beziehung zum in-
dividuellen Zellleben nicht zur Fortpflanzung.”’

According to the observations of Jordan (48) on the newt,
the chromatin threads “are distinctly traceable through the
whole history of the germinal vesicle,” although large chro-
matin granules break loose from the threads at various times
and pass over into true nucleoli. Janssens has also asserted
that in the egg of Triton the chromosomes persist throughout
the entire growth period; but in this egg the chromosomes are
entirely independent of the nucleoli.

Lubosch (61) has recently studied the history of the nucle-
oli in the ovarian egg of Triton with the avowed purpose of
testing the work of Carnoy and Lebrun. His material was
preserved and stained in a great variety of ways, and he con-
cludes that many of Carnoy and Lebrun’s results are due to
the methods of technique which they employed. As Lubosch
did not study the very young odcytes, he ventures no opin-
ion as to the origin of the primitive nucleoli. He states that
nucleoli are formed periodically at the nuclear periphery, and
that they then wander towards the centre of the nucleus where
they undergo one of three modes of dissolution: (1) through
vacuolization and subsequent differentiation into karyoplasm;
(2) through distintegration into granules; (3) through transi-
tion into various sorts of chromatin filaments, some of which

400 KING. [Vour. XIX,

are indistinguishable from the chromosomes at the time that
the latter are surrounded by a ring of nucleoli shortly before
the maturation period. While Lubosch finds that the primi-
tive chromatin network becomes extraordinarily fine at certain
stages of development, he states that it never completely dis-
appears and that it is morphologically present in the ripening
egg, although it is in a finely divided form.

From the stage of Fig. 39 until that of Fig. 50, when the
nucleus has reached its maximum size and the nucleoli have
migrated to the centre preparatory to their final disintegra-
tion, the nuclei in the ova of Bufo contain an almost endless
variety of nucleolar figures. In the nucleus shown in Fig.
39 the nucleolar bodies are of various sizes and they react
very differently towards the gentian violet and safranin stain.
The very small rounded nucleoli are karyosomes, since they
stain like the chromatin; the larger, rounded nucleoli may be
considered as plasmosomes, since they stain red and are not
connected in any way with the chromatin; the irregular body
marked X stains purple, and is a compound-nucleolus which
has not yet begun its resolution; while the small, slightly ir-
regular bodies are secondary compound-nucleoli which have
been evolved from the resolution of a large mass similar to
that shown in Fig. 35. At Y is shown a nucleolar body which
is very similar to certain of the resolving nucleoli figured by
Carnoy and Lebrun. This body is composed of a large, rounded
central plasmosome (staining uniformly red) which seems
to be giving off a number of small buds that also take the saf-
ranin. The outer surface of this plasmosome appears some-
what irregular and stains purple because a number of oxy-
chromatin granules are attached to it. This structure has
been produced, evidently, by the resolution of one of the com-
pound-nucleoli which contained only a comparatively small
amount of chromatin. The pinching off of small plasmo-
somes from a larger mass is a very common phenomenon in
the ova of Bufo, and it is evidently one of the ways in which
the number of these bodies is increased.

Several small nucleoli are shown in Fig. 39 which are com-
posed of an outer ring of substance, evidently chromatin, since

< ee
No. 2.] THE OOGENESIS OF BUFO LENTIGINOSUS. 401

it stains deep blue, surrounding a central portion which either
stains very faintly or appears colorless; similar bodies are
shown in Figs. 40, 41, 43, etc. Ata later period the central
portion of such nucleoli disappears, leaving only the chromatin
ring. Subsequently the ring breaks at some point, thus becom-
ing a crescent (Fig. 41), and it then disintegrates into small
granules. Nucleoli of this character are probably derived from
the oxychromatin of the larger compound-nucleoli, since they
seem to be found most abundantly at the stages of Figs. 39-43.
Similar nucleoli are figured by Carnoy and Lebrun and also by
Lubosch.

The oxychromatin threads produced by the resolution of the
large compound nucleoli are massed together at the stage of
Fig. 39; but they soon become scattered throughout the nucleus
and are bent and twisted in a great variety of ways (Figs.
40-43). Occasionally, as shown in Figs. 40 and 43, two of
these filaments lie parallel or cross each other in the form of
an X. Such an arrangement is purely accidental, since the
filaments never have any definite arrangement in the nucleus.
In some cases oxychromatin threads seem to be united with
nucleoli (Fig. 43); but as the nucleoli stain differently from
the filaments, it is readily seen that there is no true connection
between them.

Many of the figures given by Carnoy and Lebrun show
granular chromatin filaments strikingly like those shown in
my Figs. 40-43. These investigators consider that such fila-
ments are derived from the substance of the nucleoli, and the
contact of a nucleolus with a chromatin thread, as shown in
my Fig. 43, is considered to be proof that the chromatin
thread is being formed at the expense of the nucleolus. The
feathery chromosomes are considered by Carnoy and Lebrun
to be merely a special form of the filaments and in no way
different from the others in origin or in fate. My observa-
tions do not admit of such an interpretation, since in Bufo
the feathery chromosomes can be traced back to the contin-
uous filament formed after synizesis (Fig. 26), while the Oxy-
chromatin threads are undoubtedly derived from the chromatin

402 KING. [VoL. XIX.

which did not go into the spireme and they are always pro-
duced by the resolution of compound-nucleoli. Oxychromatin
filaments similar to those shown in Figs. 40-43 are figured in
Bouin’s work on the oogenesis of Rana. Bouin considers that
these filaments are a part of the general chromatin of the egg,
and he does not distinguish them from the true chromosomes.

By means of a series of camera drawings of all of the sections
of nuclei in about the stage of development shown in Fig. 43,
I have endeavored to ascertain the number of oxychromatin
filaments and of chromosomes at this time. While the chromo-_
somes appear to be twenty-four in every case, the number of
oxychromatin threads seems to vary from 20-50 in different
nuclei. This difference in the number of oxychromatin threads
in various cases can doubtless be attributed to the fact that
the compound-nucleoli from which the filaments are derived
vary in number and in size in different nuclei and that these
bodies do not all resolve at the same time.

Carnoy and Lebrun distinguish three distinct stages in the
development of amphibian oocytes, and they state that there
are many generations of nucleoli which alternate with various
kinds of chromatin figures; the nucleus frequently containing
one kind of structure exclusive of the other. In Bufo I have
never found an oocyte in a stage of development between that
shown in Fig. 38 and that of Fig. 50 in which the iucleus
did not contain nucleoli, chromosomes, and oxychromatin fila-
ments provided the egg had been satisfactorily preserved and
stained. As the ova grow the number of nucleoli increases;
but the number of chromosomes remains constant, and the
maximum number of oxychromatin filaments is found at the
stage of Figs. 40-43. After this time the oxychromatin
threads stain more faintly; the granules of which they are
composed gradually draw apart (Fig. 48), and finally become
scattered throughout the nucleus. Many of these minute
chromatin granules can still be found in the nucleus at the
beginning of the maturation period.

Although in Bufo there is no periodic resolution of nucle-
oli into chromatin threads followed by the development of a

No. 2.] THE OOGENESIS OF BUFO LENTIGINOSUS. 403

new generation of nucleoli from chromatin granules, there is
a constant formation of new nucleoli and a gradual dissolu-
tion of the old ones during the growth stages of the ova. The
disintegration of small nucleoli composed of a ring of chro-
matin enclosing a plasmosome body (Figs. 39-43) has already
been described. The beginning of a dissolution of some of the
larger nucleoli is shown in Fig. 42. In this nucleus many of
the nucleoli are stained black with iron hematoxylin; others
appear grayish, since they seem to have lost their capacity for
staining intensely. The latter nucleoli are gradually dissolved
in the karyoplasm; they are never resolved into chromatin
threads. Although the process of dissolution usually involves
the whole nucleolus, sometimes only a portion of it disappears
leaving one or several small, rounded bodies (Figs 4or 8) Tt
is possible that the small groups of nucleoli shown in Figs. 40
and 43 may have been formed in this manner.

As a rule the majority of the nucleolar masses which lie
in the meshes of the chromatin spireme or against the nuclear
membrane at the stage of Figs. 26-34, resolve into plasmo-
somes and oxychromatin filaments at about the time that the
larger compound-nucleoli undergo their resolution (Figs.-35;
39, Y). These masses differ from the larger ones in that they
contain a relatively greater quantity of plasmosome material
and a much smaller amount of chromatin. One or two of these
nucleolar bodies, rarely more, escape dissolution at the stage
of Figs. 35-38 and appear in later stages as slightly irregular,
round or oval structures which stain as uniformly, thougn in
many cases not as intensely, as in an earlier period (Fig. 30,
X). These bodies increase rapidly in size after the stage of
Fig. 39, and they usually undergo a somewhat different mode
of resolution from that of the other compound-nucleoli. At
an early period in the resolution of these bodies the Oxy-
chromatin, which has been attached to the outer surface of
the plasmosome substance (Fig. 40), breaks away and be-
comes scattered throughout the nucleus, being indistinguish-
able from the oxychromatin produced by the earlier resolu-
tions of nucleolar masses. Sometimes all of the plasmosome

404 KING. [Vou. XIX.

substance in these bodies forms one large rounded mass which
contains either one large vacuole or a varying number of small
ones (Fig. 40). Such a structure greatly resembles the large
vacuolated nucleoli found by Carnoy and Lebrun and also by
Leydig in the ova of various amphibians, and it is also very
similar to the “principal nucleolus” described by Maréchal
(67) in the selachian egg. In many cases the plasmosome
substance in these bodies is divided, the greater part of it
forming a large, rounded central mass which usually stains
rather faintly and appears either homogeneous (Fig. 41, R)
or vacuolated (Fig. 41, S), the remaining portion being
broken up into a varying number of small, round, deeply stain-
ing bodies which are attached, for a time, to the outer surface
of the larger mass and later separate from it to form small
plasmosomes. ©

The large plasmosome bodies shown in Figs. 40, 41 and 51,
disintegrate in various ways and at different times. In some
cases they persist as rounded, vacuolated bodies until the
germinal vesicle disintegrates at the beginning of the matur-
ation period when they are slowly absorbed by the cytoplasm;
in other cases they break open during the later growth stages
of the ova (Fig. 51, b), and subsequently divide into several
rounded portions which are gradually dissolved in the karyo-
plasm (Fig. 43). It is not uncommon to find these large
plasmosome bodies budding off portions of their substance
(Fig. 51, c, d); and it is probable that many of the nucleoli
found at the stage of Figs. 48-50 have been formed in this
way.

The central vacuole of these large plasmosomes frequently
contains a number of nucleolini which may be separated or
so joined together that they simulate a granular chromatin ©
thread (Fig. 51, C, D). These nucleolini always stain like
the plasmosome, and they are evidently granules which have
broken away from the inner surface of the ground substance
in a manner similar to that by which the small plasmosomes
are budded off from the outer surface. It seems probable that
Carnoy and Lebrun have in mind linear aggregations of

No. 2.] THE OOGENESIS OF BUFO LENTIGINOSUS. 405

nucleolini when they state that chromatin filaments are often
found in the interior of large nucleoli. As the result of an
investigation of the structure of the nucleoli in many kinds of
cells Montgomery (70) states: “I am forced to conclude tft
in all probability there are no skeins of chromatin lying in
any metazoan nucleolus, since I have never found any evidence
of chromatin in it in any metazoan cell.” This statement may
well be extended to include the nucleoli in the ege of Bufo,
since in no case have I ever found chromatin filaments in the
interior of rounded nucleoli, although they are often found
wrapped around the exterior of a nucleolus (Figs. 38, 40, 43).

In preparations stained with safranin and gentian violet
nucleolar bodies are sometimes found which are similar to the
compound-nucleoli described above in size and general outline,
although they have a very different structure as they are com-
posed of a-number of rounded plasmosomes imbedded in a
mass of chromatin granules (Fig. 51, a). These bodies are
compound-uncleoli containing a large amount of chromatin,
which for some unknown reason did not undergo a resolution
at the stage of Figs. 35-38.

Nuclei having a diameter of 0.04-0.08 mm. usually appear
as in Figs. 39-43. They contain one or two large unresolved
compound-nucleoli, a varying number of round plasmosomes
and small karyosomes, together with numerous small com-
pound-nucleoli which were set free from the large nucleolar
masses at the stage of Figs. 35-38. These small compound-
nucleoli, which I shall call secondary compound-nucleoli to
distinguish them from the larger bodies, appear homogeneous
and only slightly irregular at the stage of Figs. 39-43, and the
greater number of them are masses at the side of the nucleus
where the largest of the primary compound-nucleoli under-
went a resolution at the stage of Figs. 35-36. In a slightly
older egg metabolic processes occur which lead ultimately to
the formation of yolk. These processes are accompanied by,
if indeed they do not produce, a marked change in the ap-
pearance and in the behavior of the nucleolar bodies. At
this stage of development (Fig. 44) there is a mass of very

406 KING. [VoL. XIX.

irregular nucleolar bodies at one side of the nucleus which
greatly resemble the structures figured by Carnoy and Lebrun
as nucleoli resolving into their chromatin constituents. As
the preparation from which Fig. 44 was drawn was stained
with iron hematoxylin the nucleolar bodies appear homo-
geneous and stain very intensely. Their true character is
shown only when preparations are stained with safranin and
gentian violet. In such cases these fantastically shaped bodies
are found to be composed of a number of rounded plasmo-
somes imbedded in a meshwork of oxychromatin granules
(Fig. 45). The plasmosomes always appear homogeneous and
they invariably take the safranin stain; the chromatin stains
blue and it is always in the form of fine granules which may or
may not be strung together in a filament. There is nothing
to indicate that the chromatin in these structures is derived
from the plasmosomes or vice versa. ‘These peculiar bodies,
which are found very abundantly in the odcytes of toads with
a body length of 4-5.5 cm., are unquestionably secondary
compound-nucleoli which have increased considerably in size
during the stages of Figs. 39-43 and are now resolving into
their constituent parts, oxychromatin granules and plasmo-
somes. Soon after the stage shown in Fig. 44 these irregular
masses break up, and for a short time the nucleus contains
a number of plasmosomes surrounded by chromatin granules
(Fig. 46). Ata later period the oxychromatin granules sep-
arate from the plasmosomes and scatter thoughout the karyo-
plasm, and for the first time since before the synizesis stage
the nucleus has all of its chromatin separated from the plas-
mosome substance.

As I was unable to obtain any young toads in the fall with
a body length of over 5.5 cm., I have not been able to follow
the later changes in the odcytes in the ovaries of young fe-
males, and I have had to make use of the odcytes developing
in the ovaries of adults to complete my study of the odgenesis
of Bufo. If adult females are killed soon after the breeding
season in April or in May the ovaries are found to be filled
with young ova, many of which contain nucleolar bodies simi-

No. 2.] THE OOGENESIS OF BUFO LENTIGINOSUS. 407

lar to those shown in Fig. 44. A section of the nucleus of an
egg taken from the ovary of an adult toad killed the latter
part of April is shown in Fig. 48. The nucleus has nearly
attained its maximum size, and it is slightly oval, measuring
0.19 mm. by 0.22 mm. All of the irregularly shaped nucle-
olar bodies found at the stage of Figs. 44-46 have disappeared
and the nucleus contains a large number of round or oval
nucleoli of various sizes which are entirely distinct from the
chromatin threads. The smallest of the nucleoli, which stain
like chromatin, have evidently been formed by a fusion of a
number of the chromatin granules set free by the disintegra-
tion of the oxychromatin threads. Most of the larger nucle-
oli stain very intensely at this time and only a few of them
show, by their lessened capacity for staining, that they have
begun to dissolve. Since the majority of the nucleoli are
derived from the resolution of the secondary compound-nucle-
oli the greater number of these bodies are massed together
in one part of the nucleus. A few oxychromatin filaments in
the process of dissolution are still to be found in the nucleus at
this time.

During early growth stages the nucleus occupies the centre
of the ovum, but at or soon after the stage of Fig. 44 it begins
to move towards the future animal pole of the egg. As at
this time the nuclear membrane is usually somewhat irregular
in outline, several investigators have maintained that the
change in the position of the nucleus is brought about through
amceboid movement. This explanation does not seem to me
entirely satisfactory since in some cases the nuclear outline is
perfectly regular when the nucleus is moving towards the
upper hemisphere, and when irregularities in the nuclear out-
line are found they are invariably distributed uniformly around
the membrane, no matter by what means the egg has been pre-
served.

At the time that the nucleus is changing its position the
greater number of the nucleoli are massed together in one
part of the nucleus (Figs. 44-48). I have examined many
eggs in this stage of development and I have always found

7

ie KING. [Vou. XIX.

that the greater number of the nucleoli lie in the part of the
nucleus that is nearest the periphery of the egg. It hardly
seems probable that this arrangement would be found so con-
stantly if it had no significance. It seems to me a possibility,
at least, that the accumulation of most of the nucleoli in one
part of the nucleus may have something to do with the move-
ment of the nucleus towards the periphery of the egg. This
arrangement of the nucleoli strongly suggests also that the
polarity of the egg is determined at or soon after synizesis,
since the location of the largest of the compound-nucleoli,
from which the greater number of secondary compound-nucle-
oli are derived, indicates the part of the nucleus which will be
nearest the animal pole in the later growth stages of the
oocytes.

After the nucleus has reached its final position at the per-
iphery of the egg there is a rearrangement of the nuclear con-
tents so that the nucleoli become distributed fairly evenly
around the nuclear periphery, while the chromosomes and the
remains of the oxychromatin filaments are found in the centre
of the nucleus (Fig. 49). Whether this arrangement is due
to the activity of the nucleoli themselves, I have not been able
to determine. These bodies always appear round and they
never show processes similar to those found by Leydig and
also by Eimer (26) and considered by these investigators to
_be the means through which the nucleoli change their position

in the nucleus. It is at this stage of development shown in

Fig. 49 that the nuclear membrane is most irregular in outline,
and it is very probable that this irregularity is due to the
close proximity of the nucleoli. As a rule all of the oxy-
chromatin filaments have disintegrated at this time; the chro-
mosomes can always be found in favorable preparations, al-
though they stain very faintly.

Several investigators, among whom may be mentioned Will
(92), Fick, and Leydig, maintain that at or before the stage
of Fig. 49 nucleoli pass out of the nucleus into the cytoplasm
where they either dissolve or take part in the formation of the
yolk. Although I have examined a large number of eggs in

"No, 2.] « THE OOGENESIS OF BUFO LENTIGINOSUS. 409

which there were many hundreds of nucleoli lying close to the
nuclear membrane I have never found a single case in which a
nucleolus was passing through the membrane into the cyto-
plasm. At certain stages in the development of the ova there
are a number of rounded bodies in the cytoplasm which greatly
resemble nucleoli, and it is doubtless this similarity in ap-
pearance that has led to the assumption that the cytoplasmic
bodies are of nucleolar origin.

Soon after the stage of Fig. 49 the nucleoli leave their
peripheral position and move towards the centre of the nucleus.
Their arrangement at first is somewhat irregular (Fig. 50) ;
but later, as shown in a previous paper (King, 49; Fig. 3),
they form a closed ring which surrounds the chromosomes.
This arrangement of the nucleoli in the ovarian egg previous
to maturation seems to be characteristic of all amphibian eggs,
as it has been noted by all of the observers who have studied
this period in the development of the ova. All of the nucleoli
have begun to disintegrate by the time that the germinal
vesicle breaks down at the beginning of the maturation period.
They first lose their capacity for staining and many of them
become vacuolated. Later they break into small fragments
which are absorbed by the cytoplasm.

Although this study of the ovarian egg of Bufo has shown
that investigators of amphibian odgenesis have classed to-
gether, under the general name of nucleoli, several different
kinds of structures, it has not, unfortunately, disclosed the
manner in which these bodies are formed or their function
in the nucleus.

From the resting stage of the primary odgonium to the
synizesis period in the odcyte the nucleus of the germ-cells
contains several rounded nucleoli which stain differently from
the chromatin and there is not the slightest evidence that there
is any genetic relation between them. During synizesis the
nucleoli can still be distinguished from the chromatin (Fig.
25); but in early post-synizesis stages (Figs. 26-34) these
bodies are contained in the amorphous masses of nuclear sub-
stance (compound-nucleoli) left over after the formation of

410 KING. [VoL. XIX.

the spireme, and they cannot be followed since the large masses
stain very intensely and uniformly at this time. When the
large compound-nucleoli resolve (Figs. 35-38) they liberate,
with the secondary compound-nucleoli, many more of the
rounded nucleoli, which I have called plasmosomes, than were
found in the nucleus previous to synizesis. It is evident, there-
fore, that plasmosomes are being formed in the nucleus during
early post-synizesis stages (Figs. 26-34). Since these nucleoli
are formed only in the midst of oxychromatin granules it
seems probable that the oxychromatin is concerned in some
way with their formation; but the number and size of these
bodies and the fact that they invariably stain differently from
the chromatin seems to preclude the possibility that they are
derived from chromatin substance as Flemming (30), van
Bambeke (5), Macallum (65), Hertwig (43), Obst (7),
Schockaert (79), Carnoy and Lebrun, Fick (29), and many
others have maintained. The part played by the oxychromatin
in the formation of the plasmosomes is obscured. There is
no apparent decrease in the amount of this substance associ-
ated with an increase in the number and size of the plasmo-
somes during the early development of the odcyte, and at the
time that the oxychromatin filaments disintegrate the nucleus
apparently contains its maximum number of plasmosomes
(Fig. 48).

The plasmosomes seem to be of a plastic, semi-fluid consist-
ency; they appear homogeneous until they begin to disinte-
_ grate, and in some instances they seem to be capable of in-
creasing in size and of budding off portions of their substance.
Judging from the appearance and behavior of these bodies and
from the fact that their formation is associated with the rapid
growth of the cell and with the formation of vitelline bodies
in the cytoplasm, it seems probable that they are products of
nuclear metabolism which are possibly depositors of nutritive
substance that are to be used at a later period in the history
of the cell. This is substantially the view advocated by Kor-
schelt (56) and by Rhumbler (75). Montgomery (70-71)
is one of the few investigators who believes that the nucleoli
are of extranuclear origin. He states that in the egg of

No. 2.] THE OOGENESIS OF BUFO LENTIGINOSUS. 4II

nemerteans the nucleoli are first found closely applied to the
inner surface of the nuclear membrane. “It would seem that
the yolk is at first present in the cytoplasm in the form of a
diffused, unstainable fluid; that a portion of it, that remain-
ing in the cell body, later becomes segregated as, or chemically
changed into yolk globules; and that another portion of it
is taken into the nucleus and, after passing the nuclear mem-
brane, is changed into nucleolar substance.” Such an origin
for the plasmosomes in the ova of Bufo seems unlikely since
these bodies are not found close to the nuclear membrane until
a late period in the development of the ova.

The large nucleolar masses found in the oocyte at the stage
of Figs. 26-34 correspond evidently to the “primary nucleoli”
of Carnoy and Lebrun. I have shown that these bodies are
complex structures composed of plasmosome material and of
the chromatin which did not go into the formation of the
chromosomes and that they later resolve into their constitu-
ent parts; they are never formed entirely of chromatin, as
Carnoy and Lebrun maintain. The fantastically shaped nucle-
olar bodies found at the stage of Fig. 44 are similar in struc-
ture to the large compound-nucleoli shown in Figs. 26-34, and
they too resolve into chromatin threads and plasmosomes. In
the egg of Bufo there is never any connection between the
nucleoli and the chromosomes. Only oxychromatin goes into
the formation of the compound-nucleoli, and the oxychromatin
filaments which are formed by the resolution of these bodies do
not at once disintegrate to form a new generation of nucleoli
but they gradually break up into minute granules which seem
to be absorbed by the achromatic substance of the nucleus. It
is impossible to determine whether these granules take any
part in the formation of the chromosomes which are found on
the maturation spindle.

VII. THE CHRoMOSOMES.

At no period in the development of the odcyte does the basi-
chromatin disappear nor does it become condensed in the form
of nucleoli, and the chromosomes can be traced continuously

412 KING. [VoLt. XIX.

from the time that they are first formed by the breaking of the
spireme (Fig. 33) up to the stage when the germinal vesicle
disintegrates in preparation for the maturation mitosis. At
the time that the spireme divides longitudinally (Figs. 28-29)
the chromatin filaments are found to be composed of a series
of rounded granules from which a few fine fibres project on
either side. When the spireme breaks into chromosomes the
number of fine projections increases, evidently at the expense
of the chromatin granules (Figs. 33, 34, 36). By the time
that the odcyte has reached the stage of Fig. 39, the appear-
ance of the chromosomes has changed considerably. The
axial portion of the thread is now composed of minute, faintly
staining granules, evidently formed by the breaking up of
the larger ones, and the fine projections from the sides are
longer and more numerous than at an earlier period. The
chromosomes, of which there are undoubtedly twenty-four,
thus come to have the feathery appearance that characterizes
them from this time until the beginning of the maturation
period, and they greatly resemble the filamentous chromo-
somes found by Rickert (76, 77) in the selachian egg and by
Born in the egg of Triton. After the stage of Fig.. 39 the
chromosomes stain very faintly, since the greater part of their
substance seems to be in the form of fine fibres as it was
during the synizesis period; they can always be found, how-
ever, if the egg has been properly preserved and stained. When
the germinal vesicle is about to disintegrate the chromosomes
lose their filamentous structure and become greatly condensed,
appearing as a single series of perfectly round granules (King,
49; Fig. 8). .

The arrangement of the chromosomes in the young oocyte
depends, evidently, on the extent to which sister portions of
the spireme have separated before the spireme breaks into seg-
ments. The transverse division of a spireme like that shown
in Figs. 31 and 32 produces chromosomes that are scattered
irregularly throughout the nucleus and only occasionally
paired; while the division of a spireme similar to that shown
in Fig. 30, gives a paired arrangement of all of the chromo-

No. 2.] THE OOGENESIS OF BUFO LENTIGINOSUS. 413

somes (Fig. 33, 34). Inthe later growth stages of the odcytes
the chromosomes become widely distributed throughout the
nucleus and they seem to have no definite arrangement, al-
though it is not unusual to find two chromdsomes paired as in
Fig. 43, or two chromosomes crossed as in Fig. 40.

In a previous paper (King, 49) I have shown that, at the
time the germinal vesicle is about to break down in prepara-
tion for the maturation mitoses, the twenty-four chromosomes
come together forming twelve pairs. The chromosomes of
a pair are of the same length, but there is considerable dif-
ference in the lengths of the chromosomes of the various pairs.
At this time “two of the chromosomes may be united in the
form of an X or Y, a single or double figure eight, or they
may lie parallel for a part of their length and the ends inter-
twine in various ways.” At a slightly later period the ends of
each pair of chromosomes unite forming a closed ring. Im-
mediately following this stage the chromosomes apparently
break up into granules and, owing to the changes occurring in
the nuclear substance preparatory to the formation of the
first polar spindle, it is impossible to trace the chromatin for
a short period. When the polar spindle forms a large number
of rounded chromatin granules are found near it which soon
fuse into several irregular clumps from which the reduced
number of chromosomes (12) is formed.

It is unfortunate that the chromatin cannot be traced during
the period of the formation of the first polar spindle since it
thereby becomes impossible to identify the chromosomes of the
first polar spindle with the chromosomes that are found in
the odcyte_previous to the disintegration of the germinal
vesicle. If, however, the chromosomes can maintain their indj-
viduality in the resting nuclei of the odgonia and of the young
odcytes when the chromatin is in the form of minute granules
which are scattered irregularly along a linin meshwork or
distributed on the nuclear membrane, I see no reason why they
should be considered to lose that individuality when they
break up into granules at the beginning of the maturation
period. After all it may be through the linin that the morpho-

414 KING. [Vor. XIX.

logical continuity of the chromosomes is maintained; and it
is very probable that there is a linin connection between the
chromatin granules during the early maturation stages which
I overlooked in my previous work. When opportunity offers
I shall collect new material showing the formation of the first
polar spindle in the egg of Bufo, in the hope that with some
new method of fixation or of staining I can follow the history
of the chromatin granules and thus trace the chromatin con-
tinuously from the early growth stages of the oocytes through
to the maturation spindle.

As far as I am aware, no investigator of amphibian
oogenesis has as yet traced the chromosomes from the ovarian
egg directly into the maturation spindle. Schultze, Carnoy
and Lebrun, and Fick believe that the chromosomes of the
polar spindles are derived from chromatin nucleoli which
escape dissolution at the time that the germinal vesicle disin-
tegrates. Other investigators have tacitly assumed that the
chromosomes of the ovarian egg pass over into the maturation
spindle and they have not given any figures of the critical
stages.

Since there are two periods in the development of the egg
of Bufo when it is impossible to follow the changes which
the chromatin undergoes, it is a difficult matter to decide
when and how synapsis occurs. The first period when the
history of the chromatin is obscured is during the synizesis
stage in the young odcyte when the nuclear contents become
massed together as shown in Fig. 25 and the chromatin ap-
pears in the form of exceedingly fine granular threads. This
stage is succeeded by one in which the chromatin, which is to
form the chromosomes, is in the form of an apparently con-
tinous spireme. Later this spireme splits longitudinally and
then divides transversely forming the somatic number of sep-
arate segments. Assuming that the chromosomes maintain
their individuality during synizesis, it is obviously impossible
to determine how they were joined together in the spireme
which is formed after the synizesis stage. If the chromosomes
were joined end to end, then the splitting of the spireme shown

No, 2.] THE OOGENESIS OF BUFO LENTIGINOSUS. 415

in Figs. 28-30 is a longitudinal division of univalent chromo-
somes. On this assumption synapsis is coincident with
synizesis and, at the stage of Figs. 33-34, the nucleus contains
twelve bivalent chromosomes which are divided longitudi-
nally. This is the interpretation which Janssens has given to
the early post-synizesis stages which he finds in the ege of
Triton. The fact that in later growth stages the great major-
ity of the chromosomes are not arranged in pairs makes this
interpretation improbable for the egg of Bufo, since in the
eggs of other forms when bivalent chromosomes divide longi-
tudinally the parts remain together or are connected in some
Way.

If we assume that two chromosomes united side by side
in the spireme, then the subsequent longitudinal splitting of
the spireme is merly a separation of the chromosomes that
were previously paired, and the transverse division of the
spireme is the means by which the chromosomes are com-
pletely separated from each other. Synapsis, on this as-
sumption, does not necessarily occur during synizesis, since
the somatic number of chromosomes is evolved from the
spireme. I am inclined to believe that synizesis in the ege of
Bufo is a process by which the chromatin which bears the
hereditary qualities and is to be used for the chromosomes of
the maturation spindle is separated from the chromatin which
has other uses in the cell. This would seem to bear out
Gardiner’s (33) contention that “there are two kinds of
chromatin stuff, the one insoluble and bearing the heredity
which is to be transmitted to the daughter-cells, the other
food for the cytoplasm.” If this interpretation of synizesis
is correct, the chromosomes must have been united in pairs in
the spireme that was evolved from the synizesis stage, but
synapsis does not take place until the beginning of the matu-
ration period. This interpretation seems the more probable
since Jordan failed to find a pairing of the chromosomes in
the ovarian egg of the newt at any stage of development.

‘The second period when it is impossible to trace the history
of the chromatin occurs just previous to the formation of the

416 KING. [Vou XIX.

first polar spindle when the twelve chromatin rings break into
granules which cannot be distinguished from the granular
achromatic substance of the nucleus. The twelve bivalent chro-
mosomes that are finally formed from the mass of chromatin

t+oy

eK

L2D

CE

KK

A.—Diagrams showing the changes in the shape of the chromosomes of
the first polar spindle in the egg of Bufo and the direction of the
maturation mitoses. In both mitoses the chromosomes are
divided longitudinally.

B.—Diagrams showing the character of the maturation mitoses if the
chromosomes were united end to end in synapsis. The first
division separates univalent chromosomes; the second is a longi-
tudinal division.

C.—Diagrams showing the character of the maturation mitoses if the
chromosomes conjugated side by side during synapsis. Both

_ mitoses divide the bivalent chromatin segments longitudinally.

granules that surround the polar spindle vary somewhat in
size and in shape. When they have become arranged on the
spindle they undergo considerable modification in form, and
the longitudinal axis of the chromosome at the time that the

No. 2) THE OOGENESIS OF BUFO LENTIGINOSUS. 417

first maturation mitosis occurs is the transverse axis of the

_ chromosome at an earlier period (King, 51). In both matu-

ration mitoses the bivalent chromosomes are divided longitu-
dinally (Text-Figure I, A).

If synapsis occurs when the germinal vesicle disintegrates
then the chromosomes must have united end to end, as shown
in Text-Figure I, B, otherwise both of the maturation mitoses
are equation divisions of bivalent chromatin segments and in
neither division are univalent chromosomes separated (Text-
Figure I, C). The investigations of Stevens (87, 88) have
shown that in Sagitta synapsis takes place in the egg by a
side by side conjugation of the chromosomes and in the sperm-

- atocytes by an end to end union. This is probably the plan

that is followed in the germ-cells of Bufo if synapsis occurs
in the egg during the synizesis period. I am inclined to the
opinion that in the egg of Bufo, as in the spermatocyte, synap-
sis occurs shortly before the maturation mitoses and that the
chromosomes are united end to end. On this assumption the
first maturation division in the egg is a reduction division in
the Weismannian sense since it separates univalent chromo-
somes, and the second division only is an equation division
(Text-Figure I, B).

A. and K. E. Schreiner (80-82), who have recently exam-
ined the chromatin relations in the germ-cells of many differ-
ent forms, conclude from their studies that in the germ-cells_
of all animals the chromosomes conjugate in pairs during
synapsis, never end to end. This generalization finds an ex-
ception in the germ-cells of Bufo. In the spermatocytes of
this amphibian synapsis occurs during the synizesis stage whicn
immediately precedes the prophase of the first maturation mi-
tosis, and in the prophase and metaphase of division the chrom-
osomes behave in such a way that there seems no possibility of
avoiding the conclusion that they were united end to end in
synapsis. In the egg, as I have shown, it is not possible to
determine when or how synapsis occurs; yet the evidence at
my command seems to indicate that in synapsis the chromo-
somes are united end to end as they are in the spermatocytes.

418 KING. [Vot. XIX.

VIII. THE FORMATION OF YOLK.

One of the most difficult problems met with in the study of
amphibian odgenesis is that concerning the origin of the yolk.
This problem includes not only a consideration of the origin
and nature of the so-called “yolk-nuclei,” but it also involves
practically the whole theory of cell action since it cannot be
supposed that the yolk formation takes place independently of
nuclear activity. The anabolic processes taking place in the
cell as a result of the interaction of the nucleus and the cyto-
plasm are as yet very imperfectly understood, and until we
have obtained a clearer insight into the nuclear-cytoplasmic
relations it will not be possible to solve the problem of yolk
formation in an entirely satisfactory manner.

There is as great a diversity of opinion regarding the nature
of the yolk-nucleus and the origin of the yolk in the amphibian
egg as there is concerning the origin of the egg itself. The
first observation regarding the presence of a yolk-nucleus in
the amphibian egg were made by Cramer (23) in 1848. Ac-
cording to this investigator the cell body of the frog’s egg
contains a small granular ball which later spreads out in the
form of a half-moon around the nucleus and gives off gran-
ules which develop into yolk spherules. In 1850 Carus (19)
investigated the young egg of Rana temporaria and failed to
find the granular ball described by Cramer. He states that the
yolk first appears at the periphery of the egg in the form of
single granules as it does in the egg of Alytes obstetricans
according to the earlier observations of Vogt (90).

A few years later Thompson (89) wrote in regard to the
presence of a yolk-nucleus in the frog’s egg: “I have in gen-
eral found it present, and think it more probable that it may
be destined to form the external and larger corpuscles of the
yolk, while the clearer part immediately surrounding the germ-
inal vesicle may contribute to the production both of these and
of the finer substance in which the germinal vesicle is found
imbedded.”

As Goette failed to find a yolk-nucleus either in the egg
of Bombinator or of Bufo, Hertwig (40) is inclined to attach

No. 2] | THE OOGENESIS OF BUFO LENTIGINOSUS. 419

but little morphological value to the rounded granular ball
which he finds in the cytoplasm of the egg of Rana. “Mir
scheint er einzig and allein mit der Bildung der Dottersubstanz
in Beziehung zu stehen und eine eigenthtimliche locale An-
sammlung von Nahrstoffen darzustellen.” He suggests that
the name “Dotterconcrement” would be more appropriate for
this structure than “Dotterkern.” Kolessnikow (55) men-
tions the presence of granular yolk-nuclei in the eggs of Rana
temporaria, Rana esculenta, and Bufo variabilis, but he gives
no opinion as to their origin or use.

Henneguy (38) finds a large granular mass, presumably a
yolk-nucleus, in the egg of Rana, although he fails to find a
similar body in the egg of Bufo vulgaris, Triton teeniatus, and
Triton cristatus. Henneguy believes that wherever this body
is found it is derived from the nucleolar substance of the
nucleus and he ventures the interesting conjecture that “c’est
un organe ancestral qui, avec les éléments nucléolaires de la
vesicule germinative, correspond au macronucléus des In-
fusoires, le micronucléus étant représenté par le rdseau chro-
matique, prenant seul part aux phénoménes de fécondation.”

Jordan finds a number of granular yolk-nuclei in the egg
of the newt which he believes “arise from the cytoplasm and
usually disintegrate in the cytoplasm.” He is not sure whether
these structures are of importance in the formation of yolk
or not. Jordan’s observations regarding the fate of these yolk-
nuclei will be mentioned later.

The observations of several investigators seem to show that
nuclear substance is used in the formation of yolk. In 1884,
Will brought forward the view that in the ova of amphibians
and of insects nucleoli leave the nucleus and migrate to the
periphery of the egg where, as yolk-nuclei, they lose their
sharp contour and break up into granules which become yolk
spherules. Substantially the same view was advanced by
Leydig in 1888 to account for the origin of the yolk in the
egg of Triton. Leydig considers that the nucleolj arise in
the nucleus “als Knotenpunkte in dem feinen Netz des Re-
ticulums,” and that they move to the periphery of the nucleus

20 KING. [VoL, XIX,

where they “im losgelésten Zustande die Form und Natur
kleiner AmOben zeigen.” Subsequently they pass through the
nuclear membrane into the cytoplasm and move to the per-
iphery of the egg where they form groups of granules which
develop into yolk.

Bataillon (6) also derives the yolk in the amphibian egg
from the substance of the nucleus, but he believes that it is
formed from the chromatin. ‘Des massules chromatiques
issues de la vésicule germinative viennent donner dans le
plasma ovulaire et a la périphérie d’abord, de véritables élé-
ments cellulaires transitoires dont ils fournissent le noyau, et
prendre part a la formation simultanié des tablettes vitellines
et du pigment.”

As a result of a study of the ovarian egg of Rana and of
Necturus, Macallum (64) concludes that the peripheral
chromatin nucleoli generate a substance which diffuses grad-
ually through the nucleus into the cytoplasm. “I regard the
yolk spherules as formed by the union of a derivative of the
nuclear chromatin with a constituent of the cell protoplasm.”
Support for this view is furnished by the more recent cyto-
logical studies of Carnoy and Lebrun (15). These investi-
gators state that the greater number of chromatin granules
that are produced by the resolution of nucleoli are not used
in the formation of a new generation of nucleoli, but that they
are dissolved in the achromatin substance of the nucleus and
transformed into nucleinic acid. This acid passes by osmosis
through the nuclear membrane and is diffused through the
cytoplasm. “Dans les plages formatrices, il rencontre les
globulines de réserve imbibées d’eau, et se combine avec elles
pour former la paranucléine d’abord, la vitelline en suite... .
Nous considérons les plaques vitellines comme étant des pro- .
duits de l’activité du noyau et du cytoplasme: celui-ci fournirait
les globulines, le noyau, l’acide paranucléinique. Les vitel-
lines sont, en effet, des paranucléo-albumines, c’est-a-dire des
combinaisons de paranucléine avec un albumine qui est ici
une globuline.”’

Jordan has observed in the newt appearances which might
be interpreted as a migration of very minute granules from

No. 2.] THE OOGENESIS OF BUFO LENTIGINOSUS. 421

the germinal vesicle into the cell body, and he also is inclined
to the opinion that nucleus takes part in the formation of
yolk. “One might suppose that granules from the germinal
vesicle serve as starting points, centers of attraction or stim-
ulation as it were, while the cytoplasm perhaps through the
mediation of the yolk-nuclei, elaborates and supplies he
requisite deutoplasmic material out of nutritive elements fur-
nished it by the follicle cells.”’

Since it is seemingly impossible to harmonize these various
observations regarding the yolk-nuclei and the yolk in the
egg of amphibians, it can only be supposed, if these observa-
tions are correct, that the processes by which yolk is formed
differ in various species. ‘The details of these processes must,
therefore, be worked out for each species separately, since
there is no apparent similarity between them even in closely
related forms.

In the egg of Bufo it is possible to trace the anlage of
the yolk-nuclei back to the primordial germ-cells. As I have
already stated, there is present in the cytoplasm of these
cells a small, round, apparently homogeneous body which is
sometimes, though not invariably, separated from the cyto-
plasm by a clear area (Fig. 8, V). This body colors very
intensely with iron hematoxylin, and it always takes the saf-
ranin when sections are stained with safranin and gentian vio-
let or with safranin and Lichtgriin. In preparations stained
with Delafield’s hematoxylin and orange G. this body is
hardly discernible, since it takes the orange stain as does also
the cytoplasm. Judging from its staining reactions this body
is not chromatin; neither is it a centrosome, since the same
section of the cell may show both of these structures (Fig.
7). I have not been able to determine the origin of this body
owing to the fact that in very young tadpoles the large yolk
plaques in the primodial germ-cells obscure the other cyto-
plasmic structures, while in older tadpoles, when the yolk is
beginning to be absorbed, the small yolk granules show the
same staining reactions as this body and therefore cannot be
distinguished from it. Not until the tadpole is at least thir-

422 KINGS Viol XIX,

a

teen days old can this structure be distinguished with any
degree of certainty. I shall apply the term “vitelline body”
to this structure and also to other bodies of similar character
which appear later in the cytoplasm, reserving the term, “yolk-
nucleus” for the granular masses found in the cytoplasm at a
much later period of development.

The vitelline body divides previous to each cell mitosis (Fig.
7, V). In sections of the ovaries of young toads this struc-
ttire is found in the primary oogonia (Figs. 16-17), in the sec-
ondary oogonia (Figs. 18-19), in the young oocytes at the
critical period when the cell contents stain very faintly and
cell boundaries and nuclear outlines are made out with diff-
culty (Fig. 20), and also during synizesis and early post-
synizesis stages (Figs. 23-31).

In the early stages of development a cell rarely contains
more than one vitelline body unless it is preparing to divide.
During synizesis the vitelline body enlarges somewhat and
at a slightly later period it becomes oval and then constricts
through the middle so that it has the appearance of a dumb-
bell (Fig. 47, a); subsequently it divides into two rounded
parts (Fig. 47, b), which soon separate (Fig. 47, c). The
vitelline bodies thus formed divide repeatedly, and by the time
that the odcyte has reached the stage of Figs. 36-39, its cyto-
plasm contains a considerable number of these bodies which
vary greatly in size, although they all appear round and homo-
geneous. Sometimes at this stage a vitelline body is enclosed
in a clear area which marks it off from the cytoplasm, but
this is not a constant phenomenon. Occasionally a vitelline
body does not divide in the manner described above, but it
breaks into three small parts (Fig. 38, Y); in other cases
division is unequal and one large and one small body are
formed (Fig. 38, X). Since the vitelline bodies vary so
greatly in size and are so widely scattered throughout the
cytoplasm at the stage of Fig. 39, it seems very probable that
some of them are newly formed secretion products of the
cytoplasm which appear first as minute granules and gradually
increase in size.

No. 2.] THE OOGENESIS OF BUFO LENTIGINOSUS. 423

The vitelline bodies begin to increase in number before the
resolution of the large compound-nucleoli and’at a time when
the nucleus contains but a very few plasmosomes: they are
scattered throughout the cytoplasm, chiefly in the zone midway
between the periphery of the egg and the nuclear membrane;
and very few of them ever lie close to the nucleus. These
facts would seem to preclude the possibility that the vitelline
bodies are extruded nucleoli, although in their staining reac-
tions and in their general appearance they are strikingly like
these structures.

One of the reasons given by Will forconsidering the rounded
bodies which he finds in the cytoplasm of the egg of Rana as
extruded nucleoli is that he first finds these bodies in a light
area close to the nucleus. Preparations of young ovarian
eggs of Bufo that have been badly preserved frequently give
the impression that nucleoli lie outside of the nucleus in a
fluid space marked off from the cytoplasm. If such prepara-
tions are examined under an immersion lens, one finds that
the light area which apparently surrounds the nucleus is, in
reality, a portion of the nucleus itself, since the nuclear mem-
brane is readily found where the clear area comes in contact
with the cytoplasm. In such eggs, owing doubtless to the
imperfect penetration of the fixing fluid, all of the more fluid
portions of the nuclear substance seem to be collected at one
side or around the periphery of the nucleus, while the granu-
lar achromatin and most of the nucleoli are massed together
either in the middle of the nucleus or at one side of it. Pro-
jections from this mass sometimes extend across the fluid
substance to the nuclear membrane and thus give the appear-
ance of an ameeboid nucleus without a nuclear wall. In
nuclei of this character nucleoli are sometimes found stranded
in the fluid substance and, under low magnification, they appear
to lie in the cytoplasm. The clear area which separates the
nucleus from the cytoplasm in many eggs is doubtless an arte-
fact produced through the action of reagents: I do not think
that it is present in the living egg.

The vitelline bodies are rarely found close to the periphery
of the egg at the stages of Figs. 36-39, and I have seen noth-

424 KING. [Vor. XIX.

ing that would indicate that follicle cells or their products enter
the egg and produce these structures. As these bodies are not
extruded nucleoli it is evident that they must be considered
as secretion products of the cytoplasm itself. Since, as Bernard
(8), Chittenden (20) and others have maintained, the nucleus
is undoubtedly to be considered as an organ of constructive
metabolism which “has controlling power over the metabolic
processes in the cell, modifying and regulating the nutritive
changes” (Chittenden), it is not to be supposed that the forma-
tion of the vitelline bodies in the cytoplasm takes place inde-
pendently of nuclear activity. Although no substance can be
seen to leave the nucleus at the time that the number of vitel-
line bodies is rapidly increasing, it is not improbable that a
fluid, possibly an enzyme, passes from the nucleus into the
cytoplasm and there causes the formation of these bodies. The
same enzyme, acting in the nucleus itself, may be the cause of
the formation of the plasmosomes; for these bodies are being
produced in considerable numbers in the nucleus at the time
that the formation of vitelline bodies is taking place most
actively in the cytoplasm. On this assumption it is probable
that the vitelline bodies “bear the same relation to the cyto-
plasm that the nucleoli do to the germinal vesicle,” as Jordan
has suggested. Whether the substance out of which the vitel-
line bodies are made is supplied entirely by the cytoplasm, or
whether the follicle cells contribute material to the egg for
their formation, I have not been able to determine. I have
never found follicle cells inside of the egg, although they very
frequently enter the cells of Bidder’s organ. The function of
the follicle cells seems to be to form the egg membranes during
the early stages of development and, after the egg has left
the ovary, to aid in the absorption of the follicle sacs (King,
50).

Several investigators of amphibian odgenesis, besides Will
and Leydig, have found rounded bodies in the cytoplasm of
the ege which are doubtless of the same nature as the vitel-
line bodies in the egg of Bufo. Hertwig (42) states that the
small bodies which he finds in the cytoplasm of the egg of

No. 2.] THE OOGENESIS OF BUFO LENTIGINOSUS. “ 425

Rana are composed of a hyaline substance and appear much
like nucleoli, although they cannot be extruded nucleoli since
nucleoli never wander into the cytoplasm. Born discovered
small oval bodies near the nucleus in the cytoplasm of the
egg of Triton which he hesitates to call yolk-nuclei since
they never appear granular. Bataillon describes and figures
the division of a small body lying in the cytoplasm of the
egg of Rana which he considers to be a large nucleolus which
has passed out of the germinal vesicle. He states that this
body ordinarily disappears when the yolk is formed, and
that he once saw it transformed into pigment.

Bodies similar to the vitelline bodies in the egg of Bufo have
been found in the mammalian egg by von Winiwarter (94),
Gurwitsch (36), and von Skrobansky (85). These bodies
are present in the cytoplasm in addition to a granular yolk-
nucleus. The latter structure, according to the researches of
von Winiwarter and Gurwitsch, is homologous to the idio-
zome in the sperm-cells. The figures given by von Skrobansky
of rounded bodies in the egg of the guinea pig are very similar
to those shown in Figs. 36-38. Von Skrobansky states that
these bodies increase in number as the egg develops and that
they have a tendency to form in groups of two, three, or more
which are often surrounded by a clear area. As their appear-
ance is coincident with the disappearance of the yolk-nucleus,
he suggests that the substance of the yolk-nucleus becomes
differentiated into these rounded bodies, although it is not im-
possible that they are new differentiation products of the cyto-
plasm.

Small homogeneous bodies appearing like the vitelline bodies
in the egg of Bufo have been found in the cytoplasm of the
eggs of various arachnoids, myriapods, and vertebrates, and
classed with large granular structures as yolk-nuclei. From
the researches of Henneguy, Balbiani (3), and others, it is
evident that the term yolk-nucleus has been used in a general
way to cover a number of different structures in the cytoplasm,
as the term nucleolus has been applied to a variety of struc-
tures in the nucleus.

426 KING. [Vor. XIX.

When the toad has reached a body length of about 4 cm.
and the egg has a diameter of from 0.18-0.2 mm., there ap-
pears simultaneously in different parts of the cytoplasm a
number of irregular, granular masses which I shall call yolk-
nuclei since they are similar in appearance to the structures
described under this name by Foot (32), Henneguy, Jordan,
Calkins (14), and Munson (72). These yolk-nuclei arise as
rather small, irregular patches of granular substance that are
not sharply marked off from the surrounding cytoplasm.
There is at first no regular arrangement of these bodies; some
lie near the nucleus; others are found near the periphery of
the egg, while the majority lie in a zone midway between the
nuclear membrane and the outer boundary of the egg. When
sections are stained with any of the various combination stains
previously mentioned, these yolk-nuclei take the plasma stain
more deeply than does the cytoplasm and hence are easily
seen. It seems strange that such a keen observer as Goette
failed to find these bodies in the egg of Bombinator.

The manner in which these yolk-nuclei are formed is shown
in Fig. 46. Around one of the larger vitelline bodies there
appears a clear area, as if the vitelline body had in some way
caused a liquefaction of the surrounding cytoplasm (Fig. 46,
X). The substance of this area then becomes changed into an
irregular mass of minute granules which at first stain but
slightly darker than the cytoplasm. In some cases the vitel-
line body can be found in the centre of the yolk-nucleus (Fig.
46, Y), but as a rule it quickly loses its capacity for staining
and then disappears, evidently being used up in the formation
of the yolk-nucleus. As shown in Fig. 53, a yolk-nucleus
sometimes contains several vitelline bodies of various sizes
which stain as intensely as at the stages of Figs. 36-39. In
cases of this kind it is impossible to determine whether the
vitelline bodies in each yolk-nucleus are produced by the re-
peated division of the one vitelline body concerned in the
formation of the yolk nucleus, or whether several vitelline
bodies originally took part in the formation of a single yvolk-
nucleus. I am inclined to the former view since the vitelline

No. 2.] THE OOGENESIS OF BUFO.LENTIGINOSUS. 427

bodies grow rapidly and divide very readily both in earlier
and in later stages of development and they are rarely found
in groups of more than three before the formation of the
yolk-nuclei.

In eggs with a diameter of 0.25-0.3 mm. the yolk-nuclei
are very conspicuous since they stain more intensely than at
the stage of Fig. 46, and their number is much less than at an
earlier period as several small granular masses fuse to form
larger ones. At this stage of development the yolk-nuclei
come to have a definite arranvement in the cytoplasm, form-
ing a more or less complete ring midway between the nucleus
and the periphery of the egg (Fig. 44). This is not an acci-
dental arrangement found in a few eggs, but it is a constant
phenomenon in eggs of a given size taken from different in-
dividuals and preserved and stained in different ways. At
this time the cytoplasm contains very few large vitelline
bodies, most of these bodies having been used up in the forma-
tion of yolk-nuclei.

In the egg of the newt Jordan finds granular yolk-nuclei
similar in appearance to those found in the egg of Bufo at
the stage of Fig. 44. Jordan states that these bodies appear
about the time that the yolk is beginning to form at the per-
iphery of the egg “from points of independent origin,’ and
that there are never more than nine of these structures. In
the very young egg Jordan has found what appears to be
“localized condensations of the cytoplasm and a consequent
greater avidity for staining fluids,” and he finds all gradations
between these bodies and the granular yolk-nuclei. From his
observations Jordan concludes that “in the newt the yolk-
nuclei always arise first as condensations of the cytoplasm and
subsequently increase in size and complexity with the growth
of the egg.”’ The figures given by Jordan do not show clearly
the early development of the yolk-nuclei, although his Figs.
5, 10-12 are sufficiently detailed to indicate that the method
by which the yolk-nuclei are formed in the egg of the newt
is essentially the same as in the egg of Bufo. The subsequent
history of these bodies in the egg of the newt is similar to that

428 KING. [Vor. XIX.

of the yolk-nuclei that are first formed in the egg of Bufo
since, for a time, they le in a zone half way between the
germinal vesicle and the periphery of the egg and later draw
near to the germinal vesicle where they gradually disintegrate.
The only conjecture Jordan makes as to the probable function
of the yolk-nuclei is that “they have a real physiological sig-
nificance probably related to the construction of yolk.”

The granular yolk-nuclei found by Foot in the egg of Allo-
lobophora fcetida bear a striking resemblance to those found
in the egg of Bufo (Cf. Foot’s Figs. 4-5 with my Figs. 44
and 46). According to Foot the yolk-nuclei arise in contact
with the nucleus, but, judging from their staining reactions,
they are not derived from the chromatin as Calkins (14) main-
tains is the case in Lumbricus. As the yolk-nuclei increase in
size they become broken up, and they are either scattered in
patches throughout the cytoplasm or aggregated at the egg
periphery. Foot concludes that these yolk-nuclei are formed
of “archoplasm,” and she traces them into the attraction-
sphere, the fertilization cone, and the polar rings. Munson
finds granular yolk-nuclei in the egg of Clemmys marmorata
which are similar to the granular masses shown in Figs. 44
and 46. Munson states that these structures are formed of
“a kind of metaplasm (or archoplasm) arising in the neigh-
borhood of the germinal vesicle through the combined in-
fluence of the nucleus and cytoplasm. From the place of its
formation, it diffuses or flows throughout the cytoplasm where
it serves as a culture medium of the living substance of the
egg; in other words, it serves as food. The true yolk-bodies
are a secretion of the living substance of the cytoplasm.”

Soon after the yolk-nuclei become arranged in the form
of a ring there appears near the periphery of the egg a number
of small, round, homogeneous bodies which stain intensely
(Fig. 45). These bodies, as their subsequent history shows,
are a new generation of vitelline bodies which are directly con-
cerned with the formation of the yolk. From their peripheral
position one might, perhaps, be inclined to think that the
follicle cells are concerned in some way with the formation

No. 2.] THE OOGENESIS OF BUFO LENTIGINOSUS. 429

of these bodies. I have never found any evidence that would
support such an assumption. Since these vitelline bodies are
formed some distance from the yolk-nuclei and are at first
nearly uniform in size, it would seem as if they must be new
secretion products of the cytoplasm. ‘There is the possibility,
however, that they are derived either from the few vitelline
bodies that were left over after the formation of the yolk-
nuclei or from the granular substance of which the yolk-nuclei
are composed. The vitelline bodies increase very rapidly in
number and in size, and many of them give rise to small granu-
lar yolk-nuclei, similar to those shown in Fig. 46, which al-
Ways remain at the outer surface of the egg (Fig. 54).

While the new formation of vitelline bodies is taking place
at the egg periphery, the ring of yolk-nuclei is gradually mov-
ing towards the centre of the egg and at the stage of Fig. 54
it closely encircles the germinal vesicle. In many cases yolk-
nuclei seem to come in actual contact with the nuclear mem-
brane. Whether there is a fusion between these bodies and
the substance of the germinal vesicle, as Jordan is inclined to
believe, I am not able to state. There is no noticeable. in-
crease in the size of the nucleus or any unusual change in the
nuclear structure as one might expect to be the case were a
considerable quantity of substance taken at this time into the
germinal vesicle. .After reaching the germinal vesicle the
circle of yolk-nuclei stains less intensely and gradually dis-
appears (Fig. 56). I am inclined to the opinion that their
substance is dissolved in situ to take part later in the forma-
tion of the yolk spherules in this region of the egg. This
view agrees substantially with that advanced in 1859 by
Thompson and since advocated by Jordan.

As a rule the yolk-nuclei that are first formed have moved
close to the germinal vesicle by the time that new yolk-nuclei
are to be found at the periphery of the egg, and there is a
cytoplasmic zone between them which is free from vitelline
bodies or yolk-nuclei (Fig. 54). In exceptional cases, as
shown in Fig. 53, the formation of the peripheral vitelline
bodies and yolk-nuclei takes place even before the older yolk-

430 KING. [Vou XIX.

nuclei have become arranged in the form of a ring, and the
only portion of the cytoplasm which does not contain these
structures is that surrounding the germinal vesicle. As these
cases are found so infrequently I have not been able to de-
termine whether the yolk-nuclei later become arranged as
in Fig. 54, or whether all of them remain at the periphery of
the egg to take part in the formation of the yolk there.

In Bufo, as in other amphibians according to the investiga-
tions of Vogt, Goette, Schultze, Born, Iwakawa, Jordan, and
Dubnisson, yolk spherules first appear in the outer regions
of the cytoplasm and usually simultaneously in different parts
of the egg. There are apparently two methods by which the
first yolk spherules may be formed in the egg of Bufo. Both
of these methods sometimes take place in the same egg;
whether this is true for all eggs Iam unable to say. The yolk
develops so rapidly that it is difficult to follow the processes
of its formation in any detail.

Soon after the stage of development shown in Fig. 54 a
varying number of small, oval bodies appear in the peripheral
yolk-nuclei (Fig. 56). These bodies, which stain somewhat
less intensely than the vitelline bodies, are yolk spherules which
are being formed, evidently, from the substance of the yolk-
nuclei. As the yolk spherules increase in number the granular
yolk-nuclei fade away and they have completely disappeared
by the time that the yolk forms a continuous layer around the
periphery of the egg.

In some cases certain of the vitelline bodies at the periphery
of the egg grow very large (Fig. 55). The outlines of these
bodies become irregular (Fig. 52, a), and subsequently they
break into from two to four rounded, homogeneous pieces
(Fig. 52, b) which in turn divide into smaller bodies (Fig. 52,
c-e). As a result of the repeated division of the one vitelline
body there is formed a mass of small oval bodies (Fig. 52, f)
which are of the same size and shape as the small yolk spher-
ules, although at first they stain more deeply than the yolk
spherules and can therefore readily be distinguished from
them. Later these bodies stain less intensely and seem to pass

No. 2] THE OOGENESIS OF BUFO LENTIGINOSUS. 431

over into yolk spherules. It is very probable that the aggre-
gations of small yolk spherules shown in Figs. 55-56 have
had such an origin, although it is possible that they were de-
rived from the substance of a yolk-nucleus. During the early
stages of yolk formation the cytoplasm at the outer boundary
of the egg frequently appears vacuolated. This does not seem
to be a constant phenomenon, however, and it may be due
in part, at least, to the action of reagents.

In the egg of Bufo there are two generations of yolk-
nuclei, both formed from or under the influence of the vitelline
bodies, and both evidently concerned in the formation of yolk.
The first yolk-nuclei that are formed appear simultaneously
in different regions of the cytoplasm and they later move close
to the germinal vesicle where they gradually fade away. One
can readily trace every step in their development from the stage
of that shown in Fig. 46 to that of Fig. 56. The yolk-nuclei
belonging to the second generation are formed at the periphery
of the egg and they are transformed directly into yolk spher-
ules. The various stages in the development of these bodies
can also easily be followed. With these facts in mind the
following statement by Crampton (24) is of interest: “The
accounts of the origin of the yolk-spheres from cytoplasmic
elements at places removed from the nucleus, or from several
centres, or in all parts of the egg at once, fail to take into
consideration an earlier stage marked by the origin from the
nucleus of a true yolk-matrix which subsequently disintegrates
and spreads throughout the whole cell-body as in Molgula.”
It would seem as if enough cytological work had been done
to make it clear that one cannot deduce general rules applica-
ble to all eggs from the study of one particular egg, no mat-
ter how carefully the work may have been done.

According to my investigations the formation of the yolk
in the egg of Bufo is closely associated with the vitelline bodies
and also with the granular masses produced by them, the yolk-
nuclei. I have elsewhere stated that the vitelline bodies are
probably secretion products of the cytoplasm formed, possibly,
under the influence of an enzyme given off by the nucleus. The

432 KING. [VoL. XIX.

granular yolk-nuclei are undoubtedly composed of nutritive
material which is subsequently aggregated into yolk spherules.
In some instances the substance of the vitelline bodies seems to
be transformed directly into yolk spherules; the intermediate
stage, that of the formation of yolk-nuclei, being omitted.
This would seem to indicate that the vitelline bodies are them-
selves but aggregations of nutritive material which is in a
semi-fluid condition rather than in the form of granules. It
may be that during the early stages in the development of the
ova “yolk is present in the cytoplasm in the form of a diffused
unstainable fluid,’ as Montgomery has suggested, and that
this fluid is first collected into the rounded vitelline bodies and
jater changed into yolk spherules.

The part taken by the nucleus in the formation of yolk in
the egg of Bufo is as yet obscured. I have never seen any
nucleoli or any minute granules leave the nucleus which might
have an influence on the formation of the yolk. If, as seems
probable, the nucleus directs and controls the nutritive pro-
cesses in the cell, then in the formation of yolk it must act
either through a fluid substance which it gives out into the
cell-body, or it must exert its influence directly on the deuto-
plasmic substance of the cytoplasm. In many kinds of eggs,
according to the investigations of Conklin, Crampton, Calkins,
Foot and Floderus (31), the yolk is formed first around the
nucleus and then produced progressively towards the periphery
of the egg. In these cases it may be supposed that the cyto-
plasm surrounding the nucleus is directly stimulated by the
nucleus to produce yolk. In amphibians and many other
vertebrates the yolk first appears at the periphery of the egg.
In these cases the nucleus has a less direct influence on the
yolk formation, and this influence is probably exerted through
the action of a fluid substance which passes by osmosis through
the nuclear membrane into the cell-body. The investigations
that have seemed to show that yolk is derived directly from
nucleoli, or from chromatin, or from follicle cells, are all open
to question, and until they have been confirmed by further
research I shall be inclined to believe that yolk formation 1s

No. 2.] THE OOGENESIS OF BUFO LENTIGINOSUS. 433

one of the anabolic processes in the cell which, although it
is directly or indirectly controlled by the nucleus, does not de-
pend upon the nucleus for its material substance.

ZoOLOGICAL LABORATORY,
UNIVERSITY OF PENNSYLVANIA,
March 14, 1908.

LITERATURE.

1. Aten, B. M. The Origin of the Sex-Cells of Chrysemys. Anat.
Anz., Bd. XXIX, 1906.

2. ———. An Important Period in the History of the Sex-Cells of
Rana pipiens. Anat. Anz., Bd. XXXI, 1907.

3. Baprani, E. G. Centrosome et “Dotterkern.” Journ. de l’Anat.
et de la Physiol., t. XXIX, 1893.

4. Batrour, F, M. On the Structure and Development of the Verte-
brate Ovary. Quart. Journ. micr. Sci. Vol. XVIII, 1878.

5. BAMBEKE, C. VAN. Etat actuel de nos connaissances sur la struc-
ture du noyau cellulaire a l’état de repos. Ann. Soc. de Méd.,
1885.

6. Batartton, E. Recherches anatomiques et expérimentales sur la
métamorphose des amphibiens anoures. Ann. de l'Université de
Lyon,. t. 1], 1808.

7. Bearp, JOHN. The Germ-Cells. Zool. Jahrb., Bd. XVI, 1902.

8. Bernarp, CLAupe. Legons sur les phénomeénes de la vie. Paris,
1878.

9. Born, G. Die Reifung des Amphibieneies und die Befruchtung
unreifer Eier bei Triton taeniatus. Anat. Anz., Bd. VII, 1802.

Io. ——— Die Struktur des Keimblaschens im Ovarialei von Triton
taeniatus. Arch. mikr. Anat., Bd. XLIII, 1804.

11. Bourn, M. Histogenése de la glande génitale femelle chez Rana
temporaria. Arch. de Biol., t. XVII, 1go01.

12. Bovert, Tu. Befruchtung. Ergebnisse der Anat. u. Entwickelungs-
gesch., Bd. I, 1801.

13. Broman, I. Ueber Bau und Entwickelung der Spermien von Bom-
binator igneus. Anat. Anz., Bd. XVII, 1900.

14. CaLkxins, G. N. Observations on the Yolk-Nucleus in the Egg of
Lumbricus. Trans. N. Y. Acad. Sci., 1895.

15. Carnoy, J. B., et Leprun, H. La vésicule germinative et les globules
polaires chez les Batraciens. La Cellule, t. XII, 1897.

“16. ———. La vésicule germinative et les globules polaires chez les
Batraciens. La Cellule, t. XIV, 1808.

to
to

35-

36.

KING. [VoLt. XIX.

Carnoy, J. B., et Leprun, H. La vésicule germinative et les globules
polaires chez les Batraciens. La Cellule, t. XVI, 1890.

La vésicule germinative et les globules polaires chez les
Batraciens. La Cellule, t. XVII, 1900.

Carus, J. V. Ueber die Entwickelung des Spinneneies. Zeit. wiss.
Zool., Bd. II, 1850.

CHITTENDEN, R. H. Some Recent Chemico-Physiological Discus-
sions Regarding the Cell. Amer, Nat., Vol. XXVIII, 1894.

ConkKLIN, E. G. Organ-Forming Substances in the Eggs of Ascidi-
ans. Biol. Bull., Vol. VIII, 190s.

The Organization and Cell-Lineage of the Ascidian Egg.
Journ, Acad) NatySer. ‘Phila; Vol: XIN, 1005,

Cramer, H. Bemerkungen iiber das Zellenleben in der Entwicke-
lung des Froscheies. Muiller’s Arch. f. Anat. Physiol. u. wiss.
Med., 1848.

Crampton, H. E. Studies Upon the Early History of the Ascidian
Egg. I. The Ovarian History of the Egg of Molgula. Journ.
Morph., Vol. XV, 1899.

Dusnisson, H. Contribution a l’Etude du Vitellus. Arch. d. Zool.
Expér. et Gén., t. V, 1906.

Ermer, Tu. Ueber amodboide Bewegungen des Kernkorperchens.
Arch. mikr. Anat., Bd. XI, 1875.

Esmonp, J. Sur l'état plurinucléaire des cellules en général et des
cellules-ceufs en particulier. Bibliog. Anat., t. VI, 1808.

Fick, R. Ueber die Reifung und Befruchtung des Axolotleies. Zeit.
wiss. Zool., Bd. LVI, 1893.

Mitteilungen tber die Eireifung bei Amphibien. Ver-
handl. d. Anat. Gesellsch., 1899.

FLemmMinc, W. Zellsubstanz, Kern und Zelltheilung. Leipzig, 1882.

Fiorepus, M. Ueber die Bildung der Follikelhiillen bei den Ascidien.
Zeit. wiss. Zool., Bd. LXI, 1896.

Foor, KatHartne. Yolk-Nucleus and Polar Rings. Journ. Morph.,
Vol. XII, 1806.

Garpiner, E, G. The Growth of the Ovum, Formation of the
Polar Bodies, and the Fertilization in Polychoerus caudatus.
Journ. Morph., Vol. XV, 1899.

Gemni, J. F. Zur Eibildung bei den Anuren Amphibien, Arch.
Anat. und Phsyiol., 1896.

Gortte, ALEX. Die Entwickelungsgeschichte der Unke. Leipzig,
1875.

GurwitscH, ALEx. Idiozom und Centralkérper im Ovarialeie der
Saugethiere. Arch. mikr. Anat., Bd. LVI, 1900.

No. 2.] | THE OOGENESIS OF BUFO LENTIGINOSUS. 435

37:

38.

39.

40.

4I.
42.

43.

44.

45.

46.

47.

48.

49.

50.

Sir.

HEIMENHAIN, M. Neue Untersuchungen iiber die Centralkérper und
ihre Beziehungen zum Kern und Zellenprotoplasma. Arch. mikr.

Anat., Bd. XLIII, 1894.
Hennecuy, L. F. La Corps vitellin de Balbiani dans l’ceuf des
Vertébrés. Journ. l’Anat. et de la Physiol., t. XXIX, 1893.
HERMANN, F. Beitrage zur Histologie des Hodens. Arch mikr.
Anat., Bd. XXXIV, 1889.
Hertwic, O. Beitrage zur Kenntniss der Bildung, Befruchtung und
Theilung des thierischen Ejes. ITI. Morph. Jahrb., Bd. III, 1878.
Die Chatognathen. Jen. Zeitsch., Bd. XIV, 1880.
Ueber das Vorkommen spindeliger Kérper im Dotter
junger Froscheier. Morph. Jahrb., Bd. X, 1885.
Hertwic, R. Ueber die Bedeutung der Nucleolen. Sitzungsber. d.
Gesellsch. f. Morph. u. Physiol., Bd. XIV, 1808.
HorrMAnn, C. K. Zur Entwicklungsgeschichte der Urogenitalorgane
bei den Anamisia. Zeit. wiss. Zool., Bd. XLIV, 1886.
IwaKkawa, T. The Genesis of the Egg in Triton. Quart. Journ.
micr. Sci., Vol. XXII, 1882,
JANssENS, F. A. Das chromatische Element wahrend der Entwicke-
lung des Ovocyte des Triton. Anat. Anz., Bd. XXIV, 1904.

Spermatogénése dans les Batraciens. III. Evolution des
auxocytes males du Batracoseps attenuatus. La Cellule, XXII,
1905.
Jorpan, E. O. The Habits and Development of the Newt. Journ.
Morph., Vol. VIII, 1803.
Kinc, H. D. The Maturation and Fertilization of the Egg of
Bufo lentiginosus. Journ. Morph., Vol. XVII, 1001.
The Follicle Sacs of the Amphibian Ovary. Biol. Bull.,
Vol. III, 1902.
The Formation of the First Polar Spindle in the Egg
of Bufo lentiginosus. Biol. Bull., Vol. IX, 1905.
The Spermatogenesis of Bufo lentiginosus. Amer. Journ.
Anat., Vol. VII, 1907.
Kincssury, B. F. The Spermatogenesis of Desmognathus fusca.
Amer. Jour. Anat., Vol. I, 1901.

Kwnappe, E. Das Bidder’sche Organ. Morph. Jahrb., Bd. XI, 1886.

Kotessnikow, N. Ueber die Eientwickelung bei Batrachien und
Knochenfischen. Arch. mikr. Anat., Bd. XV, 1878.

KorscuHett, E. Ueber Kerntheilung, Eireifung und Befruchtung bei
Ophryotrocha puerilis. Zeit. wiss. Zool., Bd. LX, 1895.

66.

73:

74-

KING. [Vov. XIX,

Lams, Hon. Contribution a l’étude de la genése du vitellus dans
lovule des Amphibiens (Rana temporaria). Arch. d’Anat. micro-
scop., t. IX, 1907.

LepruNn, H. La vésicule germinative et les globules polaires chez
les Anoures. La Cellule, t. XIX, 1gor.

La vésicule germinative et les globules polaires chez les
Batraciens. La' Cellule, t. XX, 1902.

Leypic, Franz. Beitrage zur Kenntniss des thierischen Eies im
unbefruchteten Zustande. Zool. Jahrb., Bd. III, 1888.

LuzoscH, W. Ueber die Nucleolarsubstanz des reifenden Triotoneies
nebst Betrachtungen tiber das Wesen der Eireifung. Jen. Zeit.
Naturwiss., Bd. XXXVII, 1902.

McCune, C. E. The Chromosome Complex of Orthopteran Sper-
matocytes. Biol. Bull., Vol. IX, 1905.

McGrecor, J. H. The Spermatogenesis of Amphiuma. Journ.
Morph., Vol. XV, 1809.

Macatium, A. B. Contributions to the Morphology and Physiology
of the Cell. Trans. Canadian Institut., Vol. I, 1891.

On the Distribution of Assimilated Iron Compounds,
Other than Haemoglobin and Haematins, in Animal and Vege-
table Cells. Quart. Journ. micr. Sci, Vol. XXXVIII, 1895.

Marécuat, J. Ueber die Morphologische Entwickelung der Chromo-
somen im Keimblaschen des Selachiereies. Anat. Anz., Bd. XXV,
1904.

Sur lovogénése des Selaciens et de quelques autres
chordates. La Cellule, t. XXIV, 1906.

Meves, Fr. Ueber eigenthiimliche mitotische Processe in jungen
Ovocyten von Salamandra maculosa. Anat. Anz., Bd. X, 1895.

Ueber Strucktur und Histogenese der Samenfaden von
Salamandra. Arch. mikr, Anat., Bd. L, 1897.

Montcomery, TH. H. Comparative Cytological Studies with Special
Regard to the Morphology of the Nucleolus. Journ, Morph.,
Vol. XV, 1808.

Observations on Various Nucleolar Structures of the
Cells. Lectures Marine Biol. Lab. Woods Holl, 18608.

Munson, J. P.. Researches on the Ovogenesis of the Tortoise
Clemmys marmorata. Amer. Jour. Anat., Vol. III, 1904.

Nusspaum, M. Zur Differenzirung des Geschlechts im Thierreich.
Arch. mikr. Anat., Bd. XVIII, 1880.

Ozst, Pau. Untersuchungen tiber das Verhalten der Nucleolen
bei Eibildung einiger Mollusken und Arachnoiden. Zeit. wiss.
Zool., Bd. LXVI, 1899.

No.

75-

76.

77-

78.

79.

80.

81.

82.

83.

84.

85.

go.

oI.

2] THE OOGENESIS OF BUFO LENTIGINOSUS. ~° 437

Ruumpster, L. Ueber Entstehung und Bedeutung der in den Kernen
vieler Protozoen und in Keimblaschen von Metazoen vor-
kommenden Binnenkérper (Nucleolen). Zeit. wiss. Zool., Bd.
LVI, 1893.

Rtcxert, J. Zur Entwickelungsgeschichte des Ovarialeies bei Se-
lathiern. Anat. Anz., Bd. VII, 1802.

. Ueber die Verdoppelung der Chromosomen im Keim-
blaschen des Selachiereies. Anat. Anz., Bd. VIII, 1893.

St. GeorcE, LA Vatetre. Ueber die Genese der Samenkorper IV.
Die Spermatogenese bei den Amphibien. Arch. mikr. Anat.,
Bd. XII, 1876.

ScHocKaAErT, R. L’Ovogénése chez le Thysanozoon Brocchi. La
Cellule, t. XVIII, to9o01.

ScHREINER, A. UNDK.E. Die Reifungsteilungen bei den Wirbeltieren.
Anat. Anz., Bd. XXIV, 1904.

Neue Studien uber die Chromatinreifung der Geschlechts-
zellen. I. Die Reifung der mannlichen Geschlechtszellen von
Tomopteris omisciformis, Eschsholtz. Arch. de Biol., t. XXII,
1905.

Neue Studien tber die Chromatinreifung der Geschlechts-
zellen. III. Die Reifung der mannlichen Geschlechtszellen von
Salamandra maculosa (Laur.), Spinax niger (Bonap.), und
Myxine glutinosa (L.). Arch. de Biol., t. XXII, 1907.

Scuuttze, O. Untersuchungen tiber die Reifung und Befruchtung
des Amphibieneies. Zeit. wiss. Zool., Bd. XLV, 1887.

Semon, R. Studien iiber den Bauplan des Urogenitalsystems der
Wirbeltiere. Dargelegt an der Entwickelung dieses Organsystems
bei Ichthyophis glutinosus. Jen. Zeitsch. Naturwiss., Bd. XXVI,
1891.

SKropaNsky, K. von. Zur Frage tiber den sogen. “Dotterkern”
(Corpus Balbiani) bei Wirbeltieren. Arch. mikr. Anat., Bd.
LXIII, 1903.

SPENGEL, J. W. Das Urogenitalsystem der Amphibien. Arbeit. a. d.
Zool.-Zootom., Institut Wtrzburg, Bd. III.

Stevens, N. M. On the Ovogenesis and Spermatogenesis of Sagitta

bipunctata. Zool. Jahrb., Bd. XVIII, 1903.
Further Studies on the Ovogenesis of Sagitta. Zool.

Jahrb., Bd. X XI, 1904.

THOMPSON, A. Ovum. Todd’s Cyclopedia of Anat. u. Physiol., Bd.
V.

Voct, C. Untersuchungen tber die. Entwickelungsgeschichte der
Geburtshelferkréte (Alytes obstetricans). Solothurn, 1842.

Watpeyer, W. Eierstock und Ei. Leipzig, 1870.

438 KING. [Vor. XTX.

92. Witt, L. Ueber die Entstehung des Dotters und der Epithelzellen
bei den Amphibien und Insecten. Zool. Anz., Bd. VII, 1884.

93. Wrytwarter, Hans von. Recherches sur l’ovogénése et lorgano-
génése de l’ovaire des Mammiferes (Lapin et Homme). Arch.
de Biol., t. XVII, 1901.

94. ————. Nachtrag zu meiner Arbeit ttber Oogenese der Saugetiere.
Anat. Anz., Bd. XXI, 1902.

9s. Woops, F. A. Origin and Migration of the Germ-Cells in Acanthias.
Amer. Journ. Anat., Vol. I, 1902.

EXPLANATION OF PLATES.

All figures were drawn with the aid of a camera lucida. They have
been reduced one-third.

Abbreviations used in lettering the figures:

Al., alimentary tract.

Ao., aorta.

C., centrosome.

C. V., cardinal vein.

E., endoderm.

G., germ-cells.

H., heart.

L., liver.

L. M., lateral plates of mesoderm.
M., mesoderm.

N., neural tube.

No., notochord. °

Nu., nucleolus.

P., early prophase of mitosis.
T., Wolffian tubule.

V., vitelline body.

2

Fic. 1.—Portion of a transverse section through the middle of a tad-
pole six days old. X 91. j

Fic. 2—FPortion of a transverse section through the middle of a tad-
pole nine days old showing the location of the germinal ridge. X QI.

Fic. 3.—Section of the germinal ridge at the stage of Fig. 2. > 1,000.
Fic. 4.—Section of the germinal ridge in a tadpole eleven days old.
1,000.

Fic. 5.—Transverse section of a divided germinal ridge in a tadpole
thirteen days old. X 1,000.

Fic. 6.—Longitudinal section showing the extent of the germinal
ridge in a tadpole thirteen days old. XX 47.

Fics. 7-9.—Sections through the germinal ridge in a tadpole fifteen
days old showing the character of the cells at different levels. XX 1,334.

Fic. 10.—Early prophase of mitosis in a primordial germ-cell. X 1,334.

Fics. 11-12.—Equatorial plate in a primordial germ-cell. All 24 chro-
mosomes are shown. XX 1,334.

Fic. 13.—Longitudinal section of a spindle during the metaphase. Only
5 of the chromosomes are shown. 1,334.

Fic. 14—Late anaphase in a primordial germ-cell. XX 1,334.

Fic. 15.—Section of the ovary at the time when sex is first apparent.
Taken from a tadpole with very well-developed hind legs. > 1,000.

Fic. 16.—Section of a young ovary showing the beginning of the
formation of a central cavity. Taken from a tadpole about to undergo
metamorphosis. > _ 1,000.

Fic. 17.—Section of a young ovary containing a central cavity. Taken
from a tadpole at the time of metamorphosis. X 1,000.

a et ¢

THE OOGENESIS OF BUFO LENTIGINOSUS
HELEN DEAN KING

ee ee

JOURNAL OF MORPHOLOGY--VOL. XIX. NO. 2 ze %

Fic. 18.—Cyst of secondary odgonia in the resting stage. XX 1,334.

Fic. 19.—Cyst containing secondary odégonia in various stages of
mitosis. XX 1,334.

Fic. 20.—Young oocyte with oval nucleus. X 1,334.

Fic. 21—A slightly later stage than Fig. 20. The nucleus of the
oocyte has assumed a rounded form. XX 1,334.

Fic. 22.—Early growth stage of the odcyte. The nucleus contains a
well defined, apparently continuous spireme. X 1,334.

Fics. 23-24.—Stages showing the gradual condensation of the nuclear
substance previous to synizesis. XX 1,334.

Fic. 25.—Synizesis stage. XX 1,334.

Fics. 26-27.—Post-synizesis stages. Part of the chromatin has been
evolved in the form of a continuous convoluted spireme: the nucleoli and
the rest of the chromatin appear in the form of irregular masses lying
against the nuclear wall or in the meshes of the spireme. XX 1,334.

Fics. 28-29.—Stages showing the longitudinal splitting of the spireme.
X 1,334. |

Fic. 30.—Slightly later stage. The sister portions of the spireme have
begun to separate. XX 1,334.

Fic. 31.—Young odcyte surrounded by its zona pellucida. In the
nucleus the sister portions of the spireme are almost entirely separated.
X 1,334-

Fic. 32.—Section of an odcyte in which there is a complete separation
of the sister portions of the spireme. XX 1,334.

Fics. 33-34.—Nuclei of the young odcytes showing the division of the
spireme into double segments. XX 1,334.

Fic. 35.—Section of the nucleus of a young odcyte showing the begin-
ning of the resolution of the amorphous masses shown in Figs. 26-34.
X 1,334-

Fic. 36.—Section of a young odcyte showing the differentiation of one
of the amorphous masses into a meshwork of chromatin threads and
rounded nucleoli. 1,334.

Fic. 37—Section of a cyst containing odcytes in different stages of
development. X 1,000.

Fic. 38.—Stage following that of Fig. 36, showing the relation of the
nucleoli, the oxychromatin threads and the chromosomes. In the cytoplasm
are numerous vitelline bodies. XX 1,334.

Fic. 39.—Section of a young odcyte. The chromosomes are scattered
throughout the nucleus and they have assumed the feathery appearance
which characterizes them throughout the rest of the growth period. The
oxychromatin threads are entirely separated from the nucleoli and have
become very granular. In the cytoplasm are numerous vitelline bodies of
various sizes. XX 1,334.

THE OOGENESIS OF BUFO LENTIGINOSUS
HELEN DEAN KING

J Fr
OURNAL OF MORPHOLOGY--VOL. xix NO. 2

Fics. 40-41.—Sections of the nuclei in odcytes of a young toad with a
body length of 3.5 cm. A large nucleolar body, oxychromatin threads and
feathery chromosomes are shown. 1,000.

Fic. 42.—Section of the nucleus in the odcyte of a toad with a body
length of 3 cm. Some of the nucleoli stain faintly and are evidently in
the process of dissolution. X 1,000.

Fic. 43.—Section of a nucleus in an odcyte of a toad with a body
length of 4 cm. showing the fragmentation of a large nucleolar body,
scattered oxychromatin threads, and a pair of chromosomes. > 1,000. ©

Fic. 44.—Part of a section of an egg taken from a young toad with a
body leygth of 5.5 cm. The yolk-nuclei are collected in a zone lying mid-
way between the nucleus and the periphery of the egg. Diameter of the
egg is 0.23 mm.; of the nucleus, 0.11 mm. _I,000.

Fic. 45.—Drawn from an egg taken from the same ovary as that from
which Fig. 44 was taken. Differentiation of the compound-nucleoli with
the aid of safranin and gentian violet. 1,000.

Fic. 46.—Part of a section of an egg taken from a toad with a body
length of 5 cm. The yolk-nuclei are forming at the expense of the vitel-
line bodies. 1,000.

Fic. 47.—Division stages of a vitelline body. X 1,334.

Fic. 48.—Section of the nucleus of an egg taken from the ovary of an
adult toad killed the latter part of April. The plasmosomes are separated
from the chromatin and most of them are massed at one side of the
nucleus. Diameter of the nucleus, 0.2mm. X 333.

re * NTIGIN
THE OOGENESIS OF:BUFO LENTIGINOSUS , i PLATE
HELEN DEAN KING > pe

JOURNAL OF MORPHOLOGY--VOL. XIX NO. 2

Fic. 49.—Section of the nucleus of an egg taken from an adult toad
killed the latter part of April. The chromosomes occupy the centre of the
nucleus, while the plasmosomes are very evenly distributed about the
nuclear periphery. X 333.

Fic. 50.—Section of the nucleus of an egg taken from an adult toad
killed early in May. The plasmosomes have migrated to the interior of
the nucleus and they enclose the chromosomes. X 333.

Fic. 51.—Peculiar types of compound-nucleoli found in many of the
nuclei during the later development of the odcytes. XX _ 1,334.

Fic. 52.—Stages showing the formation of yolk spherules from a vitel-
line body. X 1,334.

Fic. 53.—Yolk-nuclei and vitelline bodies in an egg taken from an
adult toad killed the latter part of April. X 1,000.

Fic. 54.—Part of a section of an egg taken from a young toad with
a body length of 5.5 cm. New yolk-nuclei are forming at the periphery
of the egg, and the older ones closely surround the nucleus. _ 1,000.

Fic. 55.—Formation of yolk spherules at the periphery of an egg
taken from an adult toad killed in May. 1,000.

Fic. 56.—Part of the section of an egg taken from an adult toad killed
in May. At the periphery of the egg a layer of yolk spherules is forming
at the expense of yolk-nuclei and vitelline bodies. The layer of yolk-
nuclei around the nucleus is beginning to disappear. < 667.

THE OOGENESIS OF BUFO LENTIGINOSUS PLATE IV
HELEN DEAN KING

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URNA
JOURNAL OF MORPHOLOGY--VOL. XIX NO. 2

LAE STRUCTURE AND DEVELOPMENT "OF BLD-
DER’S ORGAN IN BUFO LENTIGINOSUS.

By HeEten DEAN KING.

At the anterior end of the testis in all of the Bufonidae is
the rounded body to which Spengel gave the name “Bid-
der’s organ.” Although many of the investigators who have
worked on the germ-cells of the Anura have examined this
organ and ventured a conjecture as to its nature and probable
function, Knappe (18) is the only one who has studied its
development in any detail. In his paper, which appeared over
twenty years ago, Knappe gives but a brief account of the
early development of this body and he pays but little attention
to the nuclear changes in the cells. Those who have more
recently worked on Bidder’s organ believe, with Knappe, that
this body is a rudimentary ovary, and they have been more
interested in studying the maner in which the cells degenerate
than in trying to determine the reasons for this degeneration.
As an investigation of the nuclear and cytoplasmic changes oc-
curring in the cells of Bidder’s organ during its early devel-
opment might possibly give some clue to the function of this
body and to the causes for the degenerative processes which
occur in it, I have studied the structure and the formation of
this organ in Bufo lentiginosus in connection with my other
work on the germ-cells of this amphibian. Especial attention
has been given in this study to the behavior of the chromatin
and to the differences between the germ-cells in Bidder’s organ
and those in the ovary which become functional eggs. For
this investigation I have made use of material prepared for
a study of the spermatogenesis and oogenesis of Bufo lentig-
inosus. Methods of fixation and of staining are given in
detail in preceding papers. .

The formation of Bidder’s organ is first apparent when a
tadpole is from fifteen to eighteen days old. Transverse sec-

439

44C KING. [Vou XIX.

tions through an embryo in this stage of development show
that the anterior portion of each genital ridge has developed
much more rapidly than the rest and that this region contains
from five to eight large primordial germ-cells (Fig. 2), while
the middle and posterior regions never contain more than
three of these cells at this time. The anterior part of the
genital ridge, which has begun to develop into Bidder’s organ,
is continuous with the part which later becomes the sex-gland,
and the cells in one region appear exactly like those in any
other (Ci. Fig. 25 Plate Voand Pics, Plate 1), At ties
ginning of its development, therefore, Bidder’s organ is com-
posed of two kinds of cells: large rounded primordial germ-
cells which have a faintly staining polymorphic nucleus; and
small peritoneal cells in which the nucleus stains very deeply
and is usually elongated. There are no intermediate stages
between these two kinds of cells, and in Bidder’s organ, as
in the sex-gland proper, the primordial germ-cells must arise
from undifferentiated embryonic tissue.

Bidder’s organ develops much more rapidly than the sex-
gland, and it has attained a considerable size long before it
is possible to ascertain the sex of the individual. During the
very early stages in the development of Bidder’s organ the
large germ-cells divide by mitosis; the stages in this process
being similar to those taking place in the cells of the sex-gland.
In the prophase of mitosis twenty-four deeply staining chro-
matin segments are formed which condense into V-shaped
chromosomes (Fig. 3, X). The spindle has a small centro-
some at each pole which is devoid of radiation (Fig. 3, Y).

It is only the early generations of germ-cells in Bidder’s
organ that are able to divide by mitosis; in later development
the division of the cells is invariably by amitosis. In a series
of papers dealing with the germ-cells of Moniezia, Child (8,
9g) has maintained that amitosis is the usual method by which
the germ-cells in this form increase in number, and he is in-
clined to believe that amitosis occurs much more frequently
in normal development than most investigators admit. Ami-
tosis is the normal method by which the germ-cells in Bidder’s

No. 2.] DEVELOPMENT OF BIDDER’S ORGAN. 441

organ increase in number after a certain period in the devel-
opment of this organ, but the cells so dividing are not capable
of becoming functional eggs. In Bufo, amitosis in the germ-
cells is undoubtedly correlated with degeneration since the
germ-cells which become functional always divide by mitosis
(King, 16).

Hoffmann (14) is, I believe, the only investigator who has
found the cells of Bidder’s organ dividing by mitosis. Knappe
states that from the beginning the increase in the number of
cells in this organ is solely through amitosis. In tadpoles of
Bufo lentiginosus it ts possible to find amitosis and mitosis oc-
curring simultaneously in Bidder’s organ (Fig. 3, A and Y),
but a cell dividing amitotically is always older than one divid-
ing by mitosis, since the nucleus of a cell has to undergo a
definite series of changes before amitosis occurs. After a cell
has once divided directly it is not capable of again dividing
by mitosis.

The resting germ-cells in Bidder’s organ appear similar to
the resting germ-cells in the sex-gland, as they.are large
round or oval cells with polymorphic nuclei which contain a
faintly staining granular reticulum and several nucleoli (Cf.
Fig. 4, Plate V and Fig. 18, Plate IL). Owing doubtless to
the rapid growth of Bidder’s organ the yolk spherules disap-
pear from its cells much sooner than from the cells of the sex-
gland, and they are rarely to be found in the anterior part of
the genital ridge after the tadpole has attained a length of
7-8 mm. When the yolk has disappeared the cytoplasm of
the germ-cells appears granular, and it is found to contain
one or two vitelline bodies (Fig. 4, V) and a centrosome (Fig.
3, C). At this stage of development there is nothing to indi-
cate that these cells differ in any way from the germ-cells
in the other portions of the genital ridge.

After the last mitotic division the cells take on the character
of young odcytes and they usually have several peritoneal cells
flattened against their outer surface (Cf. Fig. 5, Plate V and
Fig. 21, Plate II). The nucleus of the cell is no longer poly-
morphic but rounded in outline and it contains a faintly stain-

442 KING. [ VoL. XIX.

ing chromatin reticulum in the meshes of which there are
several nucleoli. The nucleus maintains its rounded form dur-
ing the later development of the oocyte and it only becomes
irregular when the cell degenerates. I cannot confirm Knappe’s
observations that the nucleus of the cells of Bidder’s organ
sometimes sends out amoeboid processes by which it moves
about to accelerate the taking up of nourishment. At the
stage of Fig. 5 the cells are usually collected in cell nests, as
are the young odcytes in the ovary. All of the cells of a nest
are in practically the same stage of development, and doubt-
less all have arisen by the repeated division of one primordial
germ-cell. During the early stages of its development Bidder’s
organ has no outer membrane, but shortly before the tadpole
undergoes its metamorphosis this body becomes surrounded
by a capsule which is formed by the peritoneal cells in a
manner similar to that by which the outer ovarian wall is
formed.

The development of the young oocytes in Bidder’s organ
parallels that of the ovarian odcytes. After the stage of Fig.
5 the cell body and the nucleus enlarge very rapidly and the
chromatin forms an apparently continuous spireme which
stains rather faintly (Fig. 6). When the nucleus has attained
a diameter of about 0.013 mm., the chromatin shows a marked
increase in its capacity for staining and the spireme, which
has become much thicker and somewhat jagged in outline, be-
gins to condense (Fig. 7). This condensation continues until
practically all the chromatin is collected in the centre of the
nucleus where it forms a loose mass of fine fibres in which
are imbedded several nucleoli (Fig. 8). This is the synizesis
stage in the odcytes of Bidder’s organ. It corresponds ap-
proximately to the stage in the contraction of the nuclear con-
tents in the ovarian odcytes shown in Plate II, Fig. 24, since
the meshwork of fibres is considerably looser and the fibres
themselves are much coarser than those in the synizesis stage
of the egg shown in Plate II, Fig. 25.

Slight as the differences appear between the synizesis stage
in the ova of Bidder’s organ and that of the ovarian oocytes,

No. 2.] DEVELOPMENT OF BIDDER’S ORGAN. 443

their effects on the latest development of the cells of Bidder’s
organ are far reaching since, after the stage of Fig. 8, the
nuclei of these cells appear, as a rule, very different from the
nuclei of the same size in the ovarian ova. The development
of the ova in Bidder’s organ is similar to that of the germ-
cells in the ovary only until the synizesis stage. During the
time that the chromatin forms a contracted mass in the centre
of the nucleus changes occur which check normal development
and eventually bring about a degeneration of the cells. Just
what these changes are it is impossible to determine. A com-
parison of the early post-synizesis stages in the cells of Bid-
der’s organ with similar stages in the ovarian ova indicates
that during the contraction period in the cells of Bidder’s
organ the chromatin does not become arranged in a normal
manner, since in later stages there is no separation of the
chromatin that is normally used for the chromosomes from
the chromatin that has other uses in the cell, as is the case
in the ovarian ova. The turning point in the development of
the ova in Bidder’s organ is, therefore, the synizesis stage.
Since normal development is not possible beyond this period,
except in rare instances, it is evident that the causes which
bring about the degenerative processes in the cells of Bidder’s
organ manifest themselves during synizesis and that they act
in such a way as to prevent a normal arrangement of the
chromatin granules. Since the amount of chromatin in the
nucleus is apparently not affected by these changes it must
be that it is the arrangement of the chromatin granules that is
the important thing in synizesis. The fact that the cells of Bid-
der’s organ show degenerative changes and divide by ami-
tosis soon after synizesis strengthens my belief that synizesis
in the egg of Bufo is a means by which the chromatin which
bears the hereditary qualities is separated from the chromatin
which has other uses in the cell. This separation is not ef-
fected during the synizesis stage in the ova of Bidder’s organ,
consequently these cells are not capable of developing into
functional eggs.

Since Bidder’s organ develops much more rapidly than the
sex-gland, it is possible, perhaps, that the rapid growth of the

444 KING. [Vor. XIX.

cells may in a measure be responsible for the deviations from
the normal processes which occur during synizesis. On this
assumption to determine the causes for the rapid growth of
Bidder’s organ would be to determine also the reason for the
degeneration of its cells. These causes must be sought through
experimental work; they cannot be determined from a mor-
phological study of this body.

Occasionally, in later development, I have found nuclei in
the cells of Bidder’s organ which were very much like nuclei
of ovarian eggs of the same size (Cf. Plate V, Fig. 20 and
Plate III, Figs. 40-43). In such cases it can only be supposed
that the nuclear changes which took place during synizesis were
nearly like those occurring in the ovarian ova and, conse-
quently, that the cells could continue for a longer time to de-
velop in a normal manner.

Stages in the development of the young oocytes of Bidder’s
organ through the synizesis stage shown in Fig. 8 are to
be found in young tadpoles in which the sex-glands are still
in an apparently indifferent state. Soon after the synizesis
period the cell nests are broken up and the ova, which are
surrounded by follicle cells, become separated by the connec-
tive tissue stroma which develops throughout the organ. The
formation and development of the ova proceeds from the
periphery centripetally; the oldest and largest cells lie to-
wards the center of the organ, the youngest cells towards the
periphery.

In tadpoles killed at the time of metamorphosis and also
in young toads one frequently finds at the periphery of Bidder’s
organ nests of young ova in various stages of synizesis. It
is doubtless such cell nests that Hoffmann and Cerruti (5)
have considered as cysts containing sperm-cells, since the cells
at this time bear but little resemblance to the later stages in
the development of the ova and they appear somewhat like
certain stages in the development of the spermatocytes. I
have never found sperm-cells in the ova of Bidder’s organ.
Oblique sections passing through the posterior part of this
organ may show the sperm-cells of the upper part of the testis

No. 2.] DEVELOPMENT OF BIDDER’S ORGAN. 445

in close contact with the large ova of Bidder’s organ, but as
von Wittich (34) states, Bidder’s organ is always clearly
marked off from the testis; one never passes gradually into
the other as Knappe and Ognew (24) maintain is the case in
Bufo vulgaris. The sharp distinction between Bidder’s organ
and the sex-gland is not maintained in the female of Bufo len-
tiginosus after the first year, since at about this time the cavity
of Bidder’s organ becomes continuous with the central cavity
of the ovary. Knappe asserts that he has found mature
spermatozoa in the cells of Bidder’s organ that have begun to
degenerate, and-he believes that these spermatozoa have de-
veloped from follicle cells that have entered the cytoplasm of
the ova. Ina recent paper (King, 17) I have shown that the
structures considered by Knappe as spermatozoa are very
probably parasites, since the figures which he gives of these
bodies are very similar to certain stages in the life cycle of a
sporozoan parasite which infects the cells of Bidder’s organ
in the American toad, Bufo lentiginosus.

As the nuclei in the cells of Bidder’s organ emerge from
synizesis the nuclear contents does not become arranged in a
manner similar to that found in the nuclei of the ovarian ova
in early post-synizesis stages. In the great majority of cases
practically all of the chromatin goes into a continuous spireme
(Fig. 9), while the greater portion of the plasmosome sub-
stance is collected into one or two rounded masses which lie
in the meshes of the spireme or against the nuclear mem-
brane (Figs. 10, 14). In some few nuclei the plasmosome
masses have a smooth outline and they color uniformly red
when preparations are stained with safranin and gentian violet
(Fig. 14). In such cases it is evident that all of the chroma-
tin, except that found in the few small karyosomes which are
scattered about the nucleus, has gone into the spireme. In
other nuclei a small amount of chromatin remains attached
to the outer surface of the plasmosomes, giving these bodies a
slightly irregular outline (Figs. 9, 10). Nucleolar masses of
this kind correspond in structure to the compound-nucleoli
found in the ovarian ova, and their subsequent fate is the

446 KING. [VoL. XIX.

same since they undergo a resolution into plasmosomes and ~
oxychromatin granules (Figs. 21-25). |

The continuous spireme found at the stage of Fig. 9 ap-
pears granular and somewhat irregular in outline. It does
not undergo a longitudinal splitting at any stage of develop-
ment, but it divides transversely into a number of segments
which are of various lengths (Figs. 10-14). These segments
are scattered throughout the nucleus and they are never found
in pairs. Camera drawings of all of the sections of a nucleus
in this stage of development show that the number of chro-
matin segments is greater than the somatic number (24). All
of the chromosomes appear granular, as a rule, and numerous
fine projections extend out from either side (Fig. 16); only
in rare instances (Fig. 20) do any of the chromosomes assume
the feathery appearance which characterizes the chromosomes
in the later growth stages of the ovarian ova. In later de-
velopment all of the chromosomes break up into minute
granules which are dissolved in the karyoplasm when the egg
degenerates.

Usually the cells begin to divide by amitosis soon after the
spireme has broken into segments. Nuclear divisions some-
times follow each other rapidly, and a cell may contain several
rounded nuclei before the cytoplasm divides (Fig. 31). Asa
rule, the largest nucleolus divides once or twice before the
nucleus itself divides. A constriction appears in the middle of
the nucleolus (Fig. 11), and it subsequently breaks into two
rounded portions which are nearly equal in size (Fig. 12).
The two nucleoli thus formed usually move to opposite sides
of the nucleus before the nucleus divides (Figs. 10,13). The
nucleus elongates considerably previous to amitosis (Fig. 15),
and it is constricted into two nuclei of approximately equal —
size (Figs. 16, 17, 19). Each nucleus contains at least one
large nucleolus and apparently half of the chromosomes (Fig.
19); and one or both of the nuclei may divide again before the
cytoplasm of the cell shows any evidence of a division (Fig.
31). Amitosis is frequently seen in the cells of Bidder’s organ
in tadpoles killed at the time of metamorphosis, and it can be

No. 2.] DEVELOPMENT OF BIDDER’S ORGAN. 447

found in practically every section of Bidder’s organ taken
from young toads or from adult males.

By the time that the nucleus has reached the stage of Figs.
10-13 the follicle cells have formed a membrane around each
egg, the zona pellucida (Figs. 27, 28, 30). Not infrequently
a blood corpuscle is to be found among the follicle cells which
lie inside of the zona pellucida in contact with the outer sur-
face of the cell (Fig. 19, B. C.).

In the early stages of the development of Bidder’s organ
the cytoplasm of the young oocytes contains a single vitelline
body which is sometimes surrounded by a clear area as it is in
the ovarian ova (Fig. 7, V). About the time of synizesis
this vitelline body divides repeatedly, and by the time that
the egg has attained a diameter of 0.035 mm. there are a num-
ber of these bodies of various sizes scattered throughout the
cytoplasm (Fig. 16). Will (33) and Leydig (20) maintain
that the rounded bodies in the cytoplasm of the egg of Rana
(which are similar to the vitelline bodies in the egg of Bufo)
are nucleoli which have migrated from the nucleus into the
cytoplasm in order to form the yolk. Such an origin for the
vitelline bodies in the cells of Bidder’s organ is impossible,
since these bodies are increasing in number at the time that
the nucleus rarely contains more than three or four small
nucleoli. As is the case in the ovarian ova, the vitelline bodies
bring about the formation of granular yolk-nuclei in the cells
of Bidder’s organ, and, at the stage of development shown
in Fig. 19, the cytoplasm of the cells sometimes contains a
large number of these structures. The arrangement of the
yolk-nuclei in the cells of Bidder’s organ differs from that
found in the ovarian ova, since these bodies are always scat-
tered irregularly throughout the cytoplasm and are never
collected in a zone midway between the nucleus and the per-
iphery of the egg. In many cases the yolk-nuclei form in a
very abnormal manner, and a cell, instead of containing a
large number of small yolk-nuclei, will contain only two or
three of these structures which are very large (Fig. 18). In
such ova one of the large yolk-nuclei almost invariably forms

448 KING. [Vou. XIX.

a cap over one side of the nucleus, thus appearing very similar
to the yolk-nuclei which, in many kinds of eggs, originate close
to the nuclear membrane.

Knappe states that in Bufo vulgaris about one year old the
cytoplasm of the cells of Bidder’s organ contains a large,
rounded, refractive body which is sharply marked off from the
cytoplasm. He maintains, furthermore, that the nucleus puts
out processes like pseudopodia which engulf this body; after-
wards the pseudopodia are slowly withdrawn and the nucleus
again becomes rounded, while the ball of substance is gradu-
ally dissolved in the karyoplasm. I have not observed this
remarkable phenomenon in the cells of Bidder’s organ in Bufo
lentiginosus. In this species of Bufo, at certain stages in
the development of Bidder’s organ, the cytoplasm of the cells
contains many granular yolk-nuclei which are more or less
rounded in form and sharply defined (Fig. 19), but I have
never seen anything that would indicate that these masses are
ever taken into the nucleus.

The inability of the cells of Bidder’s organ to develop into
functional eggs has been ascribed by Knappe to the fact that
these cells are not able to form yolk. A study of the early de-
velopment of Bidder’s organ in Bufo lentiginosus shows that
in a great many of the cells the first stages in the formation of
yolk take place, since yolk-nuclei are formed in a manner
similar to that which takes place in the ovarian ova (Fig. 19).
Except in the one case to be described later, I have never found
the development of yolk in the cells of Bidder’s organ pro-
gressing beyond the stages shown in Figs. 18-19. Were the
processes leading to yolk formation independent of nuclear
action it would seem as if they might continue beyond this
point, since there is no evidence of cytoplasmic degeneration
at the stage of Fig. 19. The degenerate condition of the
nucleus at this time is shown by the arrangement of the nu-
clear contents and by the fact that the cells are dividing
amitotically.

Fig. 26 shows a section of a cell taken from the Bidder’s.
organ of a young male toad with a body length of 2 cm. In

No. 2.] DEVELOPMENT OF BIDDER’S ORGAN. 449

this cell, and also in a few others lying near it, the cytoplasm
contains a number of yolk spherules of various sizes. These
spherules were not formed at the periphery of the egg, as is
the case with the yolk spherules that first appear in the ovarian
ova, but they were formed in, and from the substance of the
yolk-nuclei scattered throughout the cytoplasm of the cell.
The cytoplasm appears much vacuolated and the nucleus is
in an advanced state of degeneration, while many of the large
yolk spherules are disintegrating. The process of dissolution
at first affects only a part of the yolk spherule, leaving a
crescent shaped structure (Fig. 26, Y) which remains for a
time and then disappears. This egg seems to me to furnish
convincing evidence that yolk-spherules are formed from the
substance of yolk-nuclei, and it also shows that the failure of
the cells of Bidder’s organ to develop into functional eggs can-
not be due entirely to their inability to form yolk, as Knappe
claims.

The compound-nucleoli which are found in some eggs dur-
ing early post-synizesis stages (Figs. 9, 10) begin their reso-
lution, as a rule, soon after the spireme divides into seg-
ments. These bodies first become very irregular in outline
(Fig. 21), and subsequently several light areas appear in them
(Fig. 22). In later stages a differential stain, such as safranin
and gentian violet, shows that these structures are composed
of a mass of rounded plasmosomes embedded in chromatin
granules (Fig. 23). The component parts of these masses
are soon separated (Figs. 24-25), and the plasmosomes be-
come distributed throughout the nucleus. Very little chro-
matin is found in the compound-nucleoli in the cells of Bid-
der’s organ compared with the amount that goes into the
formation of the large nucleolar masses in the ovarian ova.
Usually, after the resolution of the compound-nucleoli, the
chromatin granules become scattered through the karyoplasm,
only in exceptional cases (Fig. 20) is enough of the chromatin
-separated from the spireme after synizesis to form oxychro-
matin filaments. Nucleolar masses similar to those shown in
Figs. 23-24 are evidently present in the cells of Bidder’s
organ in Bufo vulgaris since Ognew states that he sometimes

450 KING. [More cine

finds large nucleoli which have a very complicated structure,
being composed of a number of deeply staining balls sur-
rounded by a mass of granules.

No matter how many plasmosomes a nucleus may contain
there is usually one of these bodies that is larger than the
others (Fig. 29); and one of the first indications of the ap-
proaching dissolution of the nucleus is the formation of a
fluid space around this large nucleolus (Fig. 17). The nu-
cleolus itself at this time may appear homogeneous (Fig. 18),
or it may contain one or many vacuoles (Fig. 17). In
either case it stains less intensely than in earlier stages and it
gradually decreases in size (Figs. 26-27), while the vacuole
around it constantly grows larger (Figs. 18, 26, 29). As the
fluid space becomes several times the size of the original
nucleolus, its substance cannot be derived entirely from the
nucleolus, but it must be obtained in part from the dissolution
of the karyoplasm. The vacuole grows until it comes in con-
tact with the nuclear membrane (Fig. 26). It then breaks at
some point in its outer surface and the nuclear substance is in
direct contact with the cytoplasm, as during the growth of
the vacuole the nuclear membrane becomes very irregular in
outline and it disappears entirely when the vacuole breaks
(Fig. 27). While these changes are taking place the chromo-
somes gradually break up into granules that cannot be dis-
tinguished from the karyoplasm, and by the time the nuclear
membrane has disintegrated most of the chromosomes have
disappeared (Fig. 27). During the disintegration of the nu-
cleus I have never found the chromatin in the form of ir-
regular clumps as Ognew has found to be the case in the
degenerating cells of Bidder’s organ in Bufo vulgaris. The
degenerative changes just described are not found in the cells
of Bidder’s organ until the young toad has attained a length
of about 2 cm.

Degenerative changes usually appear in the cytoplasm soon
after the stage of Fig. 19, since only in rare cases is a cell able
to form yolk spherules. If a cell contains a large number of
yolk-nuclei at the time that these degenerative processes begin
the yolk-nuclei are dissolved in situ, leaving clear fluid spaces

+

Nor 2,1 DEVELOPMENT OF BIDDER’S ORGAN. 451

in the cytoplasm which at first have the shape and size of the
yolk-nuclei (Fig. 29). Later these spaces are united and the
cytoplasm then contains several large vacuoles (Fig. 27). In
cases in which the cytoplasm contains only a few large yolk-
nuclei instead of a number of small ones (Fig. 18), these
masses become sharply marked off from the cytoplasm when
degenerative changes begin and they stain much more in-
tensely than before. The appearance of these bodies thus be-
comes so very different from that of the yolk-nuclei shown in
Fig. 19 that it might be thought that they were not yolk-nuclei
but the products of a fatty degeneration of the cytoplasm. In
order to determine this point definitely several cells appearing
much like that shown in Fig. 18 were drawn with the aid of
a camera lucida and the preparations containing them were
then put in ether where they remained for about two weeks.
At the end of this time the slides were remounted and the
same cells were again drawn. The irregular granular masses
had not been affected in any way by the ether and they were
just as large and conspicuous as before. These bodies cannot,
therefore, be products of a fatty degeneration of the cytoplasm
or they would have been dissolved by the ether. Soon after the
stage of Fig. 18 these masses dissolve in situ and several large
vacuoles are formed in the cytoplasm which later become
connected as in Fig. 27.

Knappe maintains that there are four ways by which the
rudimentary eggs in Bidder’s organ disintegrate: (1) through
the penetration into the cytoplasm of follicle cells which ab-
sorb the egg substance; (2) through the development of pig-
ment in the cytoplasm which seems to bring about a gradual
collapse of the egg; (3) through the invasion of the cytoplasm
by both follicle cells and blood capillaries; (4) through pig-
ment formation combined with the penetration of blood capil-
laries into the egg. To these Ognew, from his study of
Bidder’s organ in Bufo vulgaris, adds a fifth method—a pecu-
liar process in which the follicle membrane between two ad-
jacent odcytes disappears leaving a space which grows in
breadth and finally becomes a large spherical vacuole which is

452 KING. Dore DIDS

filled with a fluid derived from the disintegration of the
odcytes. Ognew also suggests as a special process of de-
generation, the penetration of one cell of Bidder’s organ into
another.

From the very early stages in the development of Bidder’s
organ.in Bufo lentiginosus the germ-cells are surrounded by
follicle cells which are in direct contact with the outer surface
of the cytoplasm, since the cells never seem to develop a yolk
membrane as do the cells of Bidder’s organ in Bufo vulgaris
according to the investigations of Ognew. After the stage
of Fig. 29 the egg shrinks away from its zona pellucida and
its outline appears somewhat irregular (Fig. 27). At this
time many of the follicle cells lie in slight depressions in the
egg surface as if they were already beginning to enter the
egg. It would seem as if the absence of a yolk membrane
might make it possible for follicle cells to penetrate into the
eggs at any stage of development, but I have never found these
cells inside of the egg until the nucleus and the cytoplasm have
begun to degenerate. Stages in the penetration of the fol-
licle cells into the egg are shown in Fig. 30. The cells do
not show any ameeboid processes, but they appear to sink
gradually into the substance of the cytoplasm. Fig. 32 shows
a late stage in the absorption of the egg by means of the
follicle cells; the nucleus has entirely disappeared and all that
is left of the egg is a small amount of deeply staining, granu-
lar substance.

Sometimes, as shown in Fig. 30, B. C., blood corpuscles
enter the cytoplasm with the follicle cells and evidently take
part in the absorption of the egg. The zona pellucida be-
comes very irregular as the egg degenerates, and, owing to
the pressure of the surrounding eggs, it collapses after the
egg has become partially absorbed and evidently suffers the
same fate as the egg itself.

The process described above is the usual method by which
the eggs in Bidder’s organ disintegrate in all toads under two
years old. Sometimes in young toads, more often in adults,
a blood capillary breaks through the zona pellucida and forces

No. 2.] DEVELOPMENT OF BIDDER’S ORGAN. 453

its way into the egg, taking with it a number of follicle cells
(Fig. 28). In such cases the egg disappears very rapidly, its
substance being absorbed directly by the blood. I have never
found the cells of Bidder’s organ disintegrating as a result of
the formation of a large amount of pigment in the cytoplasm.
Pigment is rarely formed in the cells of Bidder’s organ in
Bufo lentiginosus, and then only in adult males. In all of
the cases which I have found the pigment was confined to a
marrow zone around the periphery of the egg; it did not
develop throughout the entire egg as is usually the case in
eggs which are degenerating in the ovary. There was nothing
in any of these eggs to indicate that the pigment was con-
cerned in any way with the degenerative processes taking
place in the cell.

Although I have never found two adjacent odcytes degener-
ating as a result of the development of a spherical vacuole
between them, I have seen what Ognew considers as de-
generation due to the penetration of one odcyte into another.
_ This phenomenon was first described by Cerruti (6) in 1905.
Cerruti states that in Bufo vulgaris the cytoplasm of one
oocyte in Bidder’s organ sometimes forces its way into the
cytoplasm of another odcyte. Later the nuclear substance of
the entering cell flows towards the place of penetration and
eventually one cell is engulfed by the other. Cerruti suggests
that this process is analogous to the entrance of follicle cells
into the egg, and that the entering cell may be considered as
a parasite of the cell into which it penetrates. Ognew con-
siders that this suggestion ventures too much since we would
have to assume a subsequent struggle for existence between
the two nuclei. Ognew does not think it possible that this
phenomenon can be associated in any way with amitosis, and
his only suggestion is that it is “a highly original process of
degeneration” which requires further study. The figures given
by Cerruti and by Ognew seem to me to show unmistakably
that both of these investigators were dealing with cases of ami-
tosis in degenerating ova which were greatly distorted in shape
on account of the pressure of the surrounding cells. Bidder’s

454 KING. [ Mowe ule

organ never grows beyond a certain size in adult males.
During the summer months the cells of this body increase
rapidly in number and also in size and they often become
so crowded together that one cell forms a decided indentation
in the surface of an adjacent cell. In preparing to divide the
nuclei of such cells frequently become greatly elongated, much
more so than shown in Fig. 17, and before the appearance
of the division membrane it might readily seem as if the sub-
stance of the nucleus was flowing in a certain direction and
that the one egg was trying to force its way into another.
Very often, during the division of these cells, currents seem
to be set up in the cytoplasm and a portion of the cytoplasm
around one nucleus may appear sharply distinct from the re-
maining cytoplasm. On superficial examination such ova may
give the impression that one cell has entered another since the
egg contains two separate nuclei; one of them being surround-
ed by cytoplasm which appears differently from the other cyto-
plasm in the cell. The cell which has apparently engulfed one
of its neighbors is never noticeably larger than the surround-
ing cells; and both of its nuclei are similar to the nuclei in
the adjacent cells, while its zona pellucida appears perfectly
intact in all places. These facts seem to me sufficient proof
that the egg in question is dividing amitotically and that it
has not been entered by another cell. I do not see how it
would be possible for one egg to enter bodily into another egg
of practically the same size without causing a break in its
zona pellucida or without producing a marked increase in the
size of the cell and a profound change in its structure.
Friedman (11) has observed that the cytoplasm of the de-
generating eggs that are sometimes found in the testis of
Rana viridis is often separated into two distinct portions which
have no regular outline but dovetail into each other in vari-
ous ways. One part of the cytoplasm has a granular structure
and stains very intensely, while the other part is apparently
homogeneous and stains very faintly. This appearance of the
cytoplasm is probably due to an abortive attempt on the part
of the cell to form yolk-nuclei similar to those shown in Fig.

No. 2.] DEVELOPMENT OF BIDDER’S ORGAN. 455

18. There is the possibility, however, that it may be caused
by currents in the cytoplasm of the degenerating eggs which
separate the more fluid portion of the cytoplasm from the
more granular, as is sometimes the case in the cells of Bid-
der’s organ.

The degenerative changes taking place in the cells of Bid-
der’s organ are very similar to those which occur in mature
amphibian eggs which have remained in the ovary after the
breeding season, according to the investigations of Bihler (4),
Dubnisson (10), Ruge (28), and others. In such eggs the
chromatin breaks up into granules and, after the disappear-
ance of the nuclear membrane, the substance of the nucleus
mingles with that of the cytoplasm, the egg being finally ab-
sorbed through the agency of follicle cells, leucocytes and blood
capillaries which have penetrated into the cytoplasm. Eggs
which are degenerating in the ovary are always heavily pig-
mented, however, while pigment is rarely developed in the
cells of Bidder’s organ and when it is present it never seems
to be concerned in the degenerative processes.

Bidder’s organ is a permanent structure in the males of
all species of the Bufonidae so far investigated. In Bufo
variabilis, Bufo cinereus, and Bufo calamita, this body dis-
appears in the female at the end of the second year. In Bufo
vulgaris, according to the observations of Knappe, Bidder’s
organ disappears in the adult female during the winter and a
new organ is regenerated during the summer months. Ac-
cording to Ognew, Bidder’s organ does not disappear in the
adult female of Bufo vulgaris during the winter, but it per-
sists as a small shrunken organ which lies near the fat bodies.
Bufo vulgaris is, therefore, the only species so far studied in
which Bidder’s organ is a permanent structure in both male
and female.

In Bufo lentiginosus Bidder’s organ disappears in the female
at the end of the second year and no traces of it are to be
found in older females. During its early development this
organ contains no central cavity, although there are a number
of intercellular spaces between the rounded ova. After the

456 KING. [Vor. XIX.

metamorphosis of the tadpole the cells of Bidder’s organ in-
crease in number very rapidly and, owing to pressure, they
are often greatly distorted. The central cavity is formed when
the cells in the interior of Bidder’s organ degenerate; this oc-
curs when a young toad has attained a body length of about
2cm. Inthe female, after the first year, the cavity of Bidder’s
organ opens into the cavity of the ovary, as Knappe has stated
is the case in Bufo vulgaris, and eventually the outer wall of
this organ becomes continuous with the epithelial covering of
the ovary. Bidder’s organ then appears as a small lobe of
the ovary which is easily distinguished from the other lobes
as the cells never develop beyond a certain stage. Bidder’s
organ then gradually decreases in size and finally disappears.
Although I have several times carefully examined entire
ovaries of mature females, I have never been able to find any
traces of this body.

In the male toad Bidder’s organ varies greatly in size and
in appearance at different seasons of the year. In the early
spring this body appears shriveled and it is somewhat irregular
in shape. Sections of Bidder’s organ taken’ from toads killed
at the height of the breeding season in April show that at this
time the organ has a very large central cavity and that it
contains a considerable number of degenerating ova and only
a few young eggs. In the early summer large numbers of new
eggs are formed at the periphery of Bidder’s organ, and this
body increases considerably in size and becomes more rounded.
During the latter part of August and in September the large
cells begin to degenerate in increasing numbers and only a
very few young ova can be found.

Ognew states that the development of Bidder’s organ is
closely associated with the development of the sex-gland. When
the sex-gland is resting, Bidder’s organ grows and the num-
ber of cells increases, but from the time that the formation of
the spermatozoa begins up to the period of sexual activity
which occurs in April and May, this organ gradually de-
creases in size. I cannot agree with Ognew that the sex-
gland is “resting” during the summer months when Bidder’s

No. 2.] DEVELOPMENT OF BIDDER’S ORGAN. 457

organ is increasing in size. My study of the spermatogenesis
of Bufo lentiginosus (King, 16) has shown that early summer
is the time when the sperm-cells are most actively dividing
and that in August and September, when large numbers of
the cells of Bidder’s organ are beginning to degenerate, the
testes are filled with spermatids and spermatozoa. The growth
of Bidder’s organ is therefore most rapid during the period
when the cells of the testis are most actively developing into
spermatozoa. The degeneration of numerous cells of Bidder’s
organ at the end of the summer is not due to the beginning
of a period of sexual activity on the part of the testes, but to
the fact that these cells have reached their maximum stage of
development and, since they can go no further, they must of
necessity degenerate. During the winter there is no active
formation of new cells in Bidder’s organ, and many of the
cells already formed gradually reach their maximum develop-
ment and then disintegrate. In the spring, therefore, Bidder’s
organ is only about one-half of its former size. New cells
are formed in great numbers in Bidder’s organ only at the
time that new cells are developing in the testes.

In adult males the nuclei of the cells of Bidder’s organ
usually contain a number of small nucleoli rather than one or
two large ones as is so often the case in the young animals.
The cytoplasm of these cells usually appears uniformly granu-
lar until it is beginning to be absorbed by the follicle cells and
by the leucocytes. Yolk-nuclei are very rarely developed in
these cells, and when they are found they always appear like
the granular masses shown in Fig. 18. Disintegration of the
cells through the agency of blood capillaries which have pen-
etrated into the cytoplasm occurs much more frequently in the
Bidder’s organ in the adult than in the young toad.

Investigations have shown that Bidder’s organ is not found
in the amphibians as a class, but that it is confined to the
Bufonidae except in rare instances. In 1830, Muller (22)
stated that a rounded body is present at the anterior end of
the testes in tadpoles of Pelobates fusca and also in those of
Rana. These observations have not been confirmed by other

458 KING. [Vou. XIX.

workers and it is probable, as Knappe suggests, that Muller
mistook tadpoles of Bufo for those of other species of am-
phibians. Knappe found a Bidder’s organ in a young male
Salamandra about two years old, but he gives no details of
its structure. As far as I have been able to determine, these
are the only recorded cases in which a Bidder’s organ has
been found in amphibians other than the Bufonidae. The
numerous cases of hermaphroditism that have been reported
in different species of Rana and the investigations of Pfluger
(25) which show that large numbers of tadpoles of Rana
temporaria are hermaphroditic would seem to indicate that
a body somewhat of the nature of the Bidder’s organ in Bufo
is not infrequently formed in Rana. I am at present investi-
gating the development of the germ-cells in a number of
species of American amphibians, and I hope later to record my
observations regarding the presence or absence of Bidder’s
organ in these forms.

Bidder’s organ has been a subject of controversy ever since
its discovery in 1758 by Rosel von Rosenhof (27), and a
number of different theories have been advanced regarding
its nature and probable function. The discoverer of this organ
considered it a part of the fat body, while Ratke (28), who
examined it in 1825, believed it to be a portion of the testis.
Three years later Jacobson (15) came to the conclusion that
all toads are hermaphrodites since the body at the anterior end
of the testis is a rudimentary ovary. This view was adopted
in 1853 by von Wittich (34), after a study of Bidder’s organ
in Bufo cinereus, and it has since been advocated by La
Valette St. George (29), Nussbaum (23), Bourne (3), Cer-
ruti (6) and Ognew. Hoffman (14) believes that Bidder’s
organ contains both ova and spermatozoa, and he therefore
considers that this body is a “rudimentare Zwitterdrtise.” On
the other hand, Bidder (1) maintains that the body at the
anterior end of the testis is not a rudimentary ovary but an
“Abtheilung des Hoden, und zwar eine auf einer niedrigen
Entwickelungsstufe stehen gebliebene, welche die Bildung des
Sperma und der Spermatozoen nun vorbereitet.” Leydig (19)

No. 2.] DEVELOPMENT OF BIDDER’S ORGAN. 459

and Spengel (31, 32) also consider that Bidder’s organ is an
accessory organ and not an ovary. ‘The latter investigator
thinks it highly probable that “dies Organ eine Rolle in den
Leistungen der Geschlechtsdrtisen, spielt, etwa in irgend einer
Beziehung steht zur Bildung des Materials von der die Ent-
wickelung neuer Ureier ausgeht, im weiblichen wie 1m mann-
lichen Geschlechte.”’

Spengel gives three reasons why he does not believe that
Bidder’s organ is a rudimentary ovary: (1) the anatomical
differences between Bidder’s organ and the true ovary consist-
ing in a lack of a central cavity in Bidder’s organ and the ab-
sence of pigment and yolk from the cells themselves; (2) the
fact that Bidder’s organ is found in the female as well as in
the male; (3) the presence of Bidder’s organ in hermaphro-
ditic toads. Later researches have rendered the first of these
reasons invalid since Bidder’s organ has been found to con-
tain a central cavity. Knappe has found pigment in the cells
of Bidder’s organ in Bufo vulgaris, and I have also found
it in Bufo lentiginosus. The formation of yolk-nuclei is a com-
mon phenomenon in the cells of Bidder’s organ in tadpoles of
Bufo lentiginosus, and in one instance (Fig. 26) I have found
the cells of Bidder’s organ developing yolk spherules. AlI-
though Bidder’s organ was found in the hermaphroditic toad
examined by Spengel it is not present in a most interesting
specimen of Bufo vulgaris recently described by Cerruti (7).
In this individual there is a well developed testis in front of
each kidney, and lying between each testis and the fat body is
an ovary which appears to be intermediate in structure between
a true ovary and Bidder’s organ. In this individual Bidder’s
organ has been able to develop further than it normally does
and it has thus become a part of the rudimentary ovary. This
development would probably not have been possible if Bid-
der’s organ were merely an accessory male organ.

The evidence brought forward by the investigators who
have more recently studied the structure of Bidder’s organ
in adult toads has been unanimously in favor of the view that
this body is a rudimentary ovary, and the results of my study

460 KING. [Vor. XIX.

of the development of this structure point to the same con-
clusion. The germ-cells of Bidder’s organ arise from primor-
dial germ-cells which are similar in character to the cells
which become functional spermatozoa or eggs, and the early
development of these cells closely follows that of the ovarian
ova up to the synizesis stage. During synizesis the cells of
Bidder’s organ appear similar to spermatocytes in which the
nuclear contents are in a contracted condition, but at no other
period in their development do they resemble in any way
stages in the development of the spermatozoa; neither are
they similar to any cells of the body except the ova. Even
when the cells of Bidder’s organ are degenerating their re-
semblance to the ovarian ova is very marked, and the degen-
erative processes occurring in them are similar to those taking
place in the mature eggs which are not expelled from the ovary.
There is, therefore, no probability that Bidder’s organ is a
portion of the testis which has been arrested in its develop-
ment to serve as an accessory male organ as Bidder, Leydig,
and Spengel maintain.

If Bidder’s organ is a rudimentary ovary there are three
possibilities that may be considered in a discussion of the
origin of this body. It is possible, as Haeckel (13) suggests,
“dass das alteste und ursprtinglichste Geschlechtsverhaltniss
die Zwitterbildung war und dass aus dieser erst secundar
(durch Arbeitstheilung) die Geschlechtstrennung hervorging.”’
This primitive hermaphroditic condition has been lost by most
of the vertebrates, although it still persists in many of the
lower forms. If the amphibians were originally hermaphro-
dites then this primitive condition of the sex-glands still ex-
ists in the Bufonidae, being indicated by the presence of Bid-
der’s organ. On this assumption Bidder’s organ is a degen-
erate ovary in the male toad and a degenerate testis in the
female.

In the female toad the cells of Bidder’s organ have no re-
semblance whatever to the sperm-cells and in their structure
and development they resemble the ovarian ova as closely as
do the cells of the Bidder’s organ in the male; neither is there

No. 2.] DEVELOPMENT OF BIDDER’S ORGAN. 461

any tendency to the development of male organs by the fe-
male in any of the Bufonidae. These facts are considered by
Marshall (21) to furnish sufficient reason to overthrow the
view that amphibians were originally hermaphroditic. In spite
of the objections that can be brought against it, this theory
seems to me to offer the most satisfactory explanation of the
presence of Bidder’s organ in Bufo. It is conceded by most,
1f not by all, zoologists that the spermatozoa are more highly
differentiated than the ova. It is therefore only natural to
suppose that in a degenerate sex-gland, such as Bidder’s
organ, the germ-cells would follow in the course of their de-
velopment the type of the least specialized germ-cells, the ova,
rather than that of the more highly specialized spermatozoa.
Such an organ would, therefore, have the same structure in
all animals regardless of sex. According to this view it is
only necessary to assume that Bidder’s organ has degenerated
in the female more than it has in the male in order to have the
conditions in this body what we find them at the present time.
Since Bidder’s organ usually disappears in the adult female,
although it persists throughout the lifetime of the male, there
is good reason to believe that this body is more degenerate in
the female than in the male. That the Bufonidae, which are
among the most highly differentiated of the amphibians,
should retain a primitive hermaphroditic condition of the gen-
ital organs when such a condition 1s not found at the present
time in other classes of amphibians, even among forms which
are considered as primitive or degenerate types, is not an ob-
stacle in the way of the theory outlined above. A some-
what similar condition is found among certain fishes, and
many of the higher vertebrates have retained primitive organs
which are at present in a degenerate condition and seemingly
of no use to the individual.

Marshall has suggested that the formation of Bidder’s organ
“may be regarded as due to a further extension backward of
that tendency to degeneration and atrophy which has caused
the conversion of the most anterior part of the germinal ridge
into the fat body.” In accounting for the similarity in the

462 KING. [Vor. XIX.

appearance and in the development of the cells of Bidder’s
organ in the two sexes, Marshall states that the “degenera-
tion of the male genital gland may be regarded as taking the
form of a reversion to the more primitive ovarian type.” Ac-
cording to the investigations of Spengel (35), Semon (30),
Goglio-Tos (12), and Bouin (2), the anterior portion of the
genital ridge, which develops into the fat body, is composed
‘entirely of small connective tissue cells. Sections of the young
tadpoles of Bufo lentiginosus show that the germ-cells are
never found anterior to Bidder’s organ in this amphibian. In
Bufo the germ-cells are not derived from peritoneal cells but
from undifferentiated embryonic tissue. It hardly seems prob-
able, therefore, that a mass of cells having a different origin
from the germ-cells and totally unlike them in structure ever
belonged to the sex-gland proper at any period in the history
of the race. In very young tadpoles the cells which are to
develop into the fat body form a forward extension of the
genital ridge, but this does not necessarily indicate that they
were primarily sex-cells. I am strongly inclined to believe
that the peritoneal cells which form the fat body have second-
arily come into connection with the anterior end of the genital
ridge and that Bidder’s organ marks the extreme anterior
boundary of the sex-gland. If this be true, then Marshall's
theory is untenable since the cells forming the fat body are
not germ-cells, and even Marshall himself believes that the
cells of Bidder’s organ are degenerate ova.

There is a third possibility regarding the origin of Bidder’s
organ which may be suggested, although little can be said in
its favor. Bidder’s organ may, perhaps, be the remains of a
primitive sex-gland which was functional when the Bufonidae
were sexually mature in their larval state, as is the condition
of the Axolotl at the present time. On this assumption the
ovary and testis are structures secondarily acquired when the
reproductive activity became manifested at a later period in
the life of the individual. The similarity in the appearance of
the cells of Bidder’s organ in both sexes and their resemblance
to ova can be accounted for on the supposition that, as the

No. 2.] DEVELOPMENT OF BIDDER’S ORGAN. 463

organ is degenerate in both sexes, its cells have taken on the
character of the least specialized germ-cells, tne ova. The
Axolotl is the only known amphibian that reproduces while
in a larval condition, and its genital organs are similar to
those of other salamanders. Since it is probable that neotenia
in this form is a phenomenon of adaptation rather than a
primitive condition, there is little ground for a belief that the
amphibians as a class were ever sexually mature in a larval
state.

The function of Bidder’s organ is as yet undetermined.
Since this structure is confined chiefly to the Bufonidae it
hardly seems as if it could have an important role in the
development of the sex-cells, as Spengel claims; neither can
it be considered as a storehouse of reserve material that 15 to
be used during the hibernation period, since measurements
made of this body at different times of the year show that it
loses not more than one-half of its volume during the winter
months. As a rudimentary ovary Bidder’s organ is appar-
ently functionless, although further research, possibly by
experimental means, may determine the part played by this
body in the life history of the individual.

LITERATURE.

1. Brpper, F. H. Vergleichende anatomische und histologische Unter-
suchungen tiber die mannlichen Geschlechts- und Harnwerkzeuge
der nackten Amphibien. Dorpat, 1846.

2. Bourn, M. Histogenése de la glande génitale femelle chez Rana
temporaria. Arch. de Biol., t. XVII, 19or.

3. Bourne, A. G. On Certain Abnormalities in the Common Frog
(Rana temporaria). Quart. Journ. Micr. Sci., Vol. XXIV, 1884.

4. Buuter, A. Riickbildung der Eifollikel bei Wirbelthieren IT. Morph.
Jahrb., Bd. XXXI, 1902.

5. Cerrut1, A. Contribuzione per lo studio dell’ organo di Bidder nei
Bufonidi I. Prosenza di spermii nell’ organo.: Boll. della Soc.
di Naturalisti in Napoli, Vol. XVII, 1903.

6. Cerruti, A. Contribuzione per lo studio dell’ organo di Bidder nei
Bufonidi II. Di una speciale penetrazione di ovule adiacenti nel
Bufo vulgaris, Laur. Atti della Reale Accad. della Sci. Fisiche e
matematiche, Vol. XII, 1905.

464 KING. [Vou. XIX.

7. Cerruti, A. Sopra due casi di anomalia dell’ apparato riproduttore
nel Bufo vulgaris, Laur. Anat. Anz., Bd. XXX, 1907.

8. Cuitp, C. M. Studies on the Relation Between Amitosis and Mito-

sis. Development of the Ovaries and Odgenesis in Moniezia. Biol.
Bull., Vol. XII, 1907.

9. Curitp, C. M. Studies on the Relation Between Amitosis and Mito-
sis. II. Development of the Testes and Spermatogenesis in
Moniezia. Biol. Bull., Vol. XII, 1907.

10. Dusnisson, H. Contribution a l’étude du vitellus. Arch. de Zool.
exper. et gen, t. V, 1006.

Ir. FrrepMan, Ff. Rudimentare Eier im Hoden von Rana viridis. Arch,
mikr. Anat., Bd. LII, 1808.

12. GrcLio-Tos, EF. Sull’ origine dei Corpi Grassi negli Anfibi. Atti R.
Accad. Sci. Torino, Vol. XXXI, 1895.

13. HaArckeLt, Ernst. Anthropogene oder Entwickelungsgeschichte des
Menschen. Leipzig, 1874.

14. HorrMan, C. K. Zur Entwickelungsgeschichte der Urogenitalorgane
bei den Anamisia. Zeit. wiss. Zool., Bd. XLIV, 1886.

15. Jacosson, H. Det kongelige Danske Videnskabernes Selskabs Natur-
videnskabelige og Mathematiske Afhandlinger. Tredje Deel., 1828.

16. Kine, H. D. The Spermatogenesis of Bufo lentiginosus. Amer.
Joins Anat viol. Villestoo72

Kine, H. D. Bertramia bufonis, a New Sporozoan Parasite of Bufo
lentiginosus. Proc. Acad. Nat. Sci., Phila., 1907.

18. Kwnappe, E. Das. Bidder’sche Organ. Morph. Jahrb., Bd. XI, 1886.

19. Leypic, F. Anatomisch-histologische Untersuchungen tiber Fische
und Reptilien. 1853.

20. Lerypic, F. Beitrage zur Kenntniss des thierischen Eies im unbe-
fruchteten Zustande. Zool. Jahrb., Bd. III, 1888.

21. Marsuati, A. M. On Certain Abnormal Conditions of the Repro-
ductive Organs in the Frog. Journ. Anat. and Physiol., Vol.
XVIII, 1884.

22. Mutter, J. Bildungsgeschichte der Genitalien. 1830.

23. Nusssaum, M. Zur Differenzirung des Geschlechts im Thierreich.
Arch. mikr. Anat., Bd. XVIII, 1880.

24. Ocnew, S. J. Materialen zur Histologie des Bidderschen Organs
der Kroten. Arch. mikr. Anat., Bd. LX XI, 1908.

25. Pritcer, E. Ueber die das Geschlecht bestimmenden Ursachen und
die Geschlechtsverhaltnisse der Frosche. Arch. fiir die gesammte
Phys., Bd. XXIX, 1882.

6. Ratuke, H. Beitrage zur Geschichte der Thierwelt III. Neueste
Schriften der Naturforscher Gesellsch. in Danzig, Bd. I, 1825.

to

No.

30.

sik:

33.

34.

2.] DEVELOPMENT OF BIDDER’S ORGAN. 405

ROsEL von Rosenuor, A. J. Historia naturalis ranarum. 1758.

Ruce, G. Vorgange am Eifollikel der Wirbelthiere. Morph. Jahrb.,
Bd. XV, 1880.

St. Grorce, La Vaterre. Zwitterbildung beim kleinen Wassermolch
(Trioton taeniatus). Arch. mikr. Anat., Bd. XLV, 188s.

Semon, R. Studien tiber den Bauplan des Urogenitalsystems der
Wirbelthiere darlegt an der Entwickelung dieses Organsystems
bei Ichtkyophis glutinosus. Jenais. Zeit. Naturwiss., Bd. XIX,
1802.

SPENGEL, J. W. Das Urogenitalsystem der Amphibien. Arbeit a. d.
zoolog.-zootom. Inst. in Wiirzburg, Bd. I, 1876.

SPENGEL, J. W. Zwitterbildung bei Amphibien. Biol. Centralblatt,
Bd. IV, 1884.

Wit, L. Ueber die Entstehung des Dotters und der Epithelzellen
bei den Amphibien und Insecten. Zool. Anz., Bd. VII, 1884.

Wrrticu, Dr. von. Beitrage zur morphologischen und histologischen
Entwickelung der Harn- und Geschlechtswerkzeuge der nackten
Amphibien. * Zeit. wiss. Zool., Bd. IV, 1853.

EXPLANATION OF PLATES.

All figures were drawn with the aid of a camera lucida. They have
been reduced one-third.

Fic. 1.—Outline drawing of the genital organs of a toad killed at the
time of metamorphosis. C. A., corpus adiposum; B. O., Bidder’s organ;
O., ovary; R., kidneys.

Fic. 2—Section of Bidder’s organ taken from a tadpole 17 days old.
X_ 1,000.

Fic. 3.—Section of Bidder’s organ taken from a tadpole 35 days old.
<_ 1,000.

Fic. 4.—Resting stage of a primordial germ-cell in Bidder’s organ.
V., vitelline bodies. XX 1,334.

Fic. 5.—Young oocyte in Bidder’s organ. X 1,334.

Fic. 6.—Growth stage of a young oocyte. X1I,334.

Fic. 7—Beginning of the condensation of the chromatin spireme lead-
ing to synizesis. X 1,334.

Fic. 8—Synizesis stage. X 1,334.

Fics. 9-10.—Early post-synizesis stages. The chromatin is in the form
of a continuous spireme. XX 1,334.

Fics. 11-14.—Post-synizesis stages showing the division of the spireme
into segments. XX 1,334.

Fic. 15—The beginning of amitotic division in the nucleus of a cell
in Bidder’s organ. X 1,334.

Fics. 16, 17.—Later stages in the amitotic division of a cell. X 1,000.

Fic. 18.—Section of an odcyte which has begun to degenerate. A fluid

space has formed around the large nucleolus and the yolk material is col-
lected in several masses, one of which lies against the nucleus. XX _ 1,000.

Fic. 19.—Section of an egg in Bidder’s organ taken from a toad killed
at the time of metamorphosis.. Yolk-nuclei are forming in the cytoplasm.
>< 4.000!

Fic. 20.—Section of the nucleus of a cell in Bidder’s organ which 1s
very similar to nuclei of the same size found in the ovarian odcytes. X
1,000.

Fics. 21-25.—Stages in the resolution of compound-nucleoli in the cells
of Bidder’s organ. X 1,334.

DEVELOPMENT OF BIDDER’S ORGAN

HELEN DEAN KING —
7

Jou
SURNAL OF MORPHOLOGY--VOL, xix NO
hep

~

Fic. 26.—Section of an odcyte in Bidder’s organ in which yolk spher-
ules were formed. Taken from a young male toad with a body length of
21cm 000:

Fic. 27.—Section of a degenerating egg in Bidder’s organ. Taken from
a young male toad with a body length of 4.5 cm. 1,000.

Fic. 28.—Part of a section showing the penetration of a capillary into
a degenerating egg. Taken from an adult male toad killed in July.
> 1,000.

Fic. 29.—Section of a degenerating egg taken from a young male
toad with a body length of 5 cm. ™ 1,000.

Fic. 30.—Part of a section of a degenerating egg into which blood
capillaries (B. C.) and follicle cells have entered. Taken from a Vane
male toad with a body length of 5 cm. 1,000.

Fic. 31.—Outline drawing of a section of a multinucleated egg in
Bidder’s organ.

Fic. 32.—Section of a degeneration egg containing numerous follicle
cells. Taken from a young female with a body length of 5 cm. X 1,000.

DEVELOPMENT OF BIDDER'S ORGAN

HELEN DEAN KING

RNAL OF MORPHOLOGY--VOL. XIx NO

JOU

Rit DEVELOPMENT OF THE ADHESIVE, ORGAN
AND HEAD MESOBLAST OF AMIA=

JAcoB REIGHARD AND JESSIE PHELPs.

In 1895? it was noticed by one of us that, at a certain
stage in its development, the adhesive organ of Amia con-
sists of a pair of diverticula whose walls and lumina are
continuous with the corresponding parts of the foregut. Two
years later we undertook a study of the development of this
organ in order to determine whether it originates from the
entoblast, as indicated by this observation, or from the ecto-
blast, as claimed by previous investigators of Amia, Aci-

*From the Zoological Laboratory of the University of Michigan, Ann
Achor, Mich. U.S: A. No. 116.

*In 1895 I noticed the connection referred to in this paragraph between
the adhesive organ of Amia and the corresponding parts of the foregut.
Two years later Miss Phelps undertook, under my direction, to trace
the complete history of this organ. When Miss Phelps’ work had been
completed two brief preliminary notes were published (Phelps, 1899, 1900),
but it seemed best, before final publication, to add the history of the head
mesoblast in so far as this is related to the adhesive organ. For this
part of the paper, as well as for the theoretical matter (see Reighard,
1902), I am responsible. The publication of the paper has been from time
to time postponed in the hope that it might follow the “Normentafel of
Amia” the preparation of which had been begun. The Normentafel has
been greatly delayed by my inability to use my eyes for microscopic work,
and I do not now know when it may be completed. The recent appear-
ance of a paper on “The Adhesive Organ of Amia” by Eycleshymer and
Wilson (1908) makes desirable the immediate publication of the present
more detailed study. It is printed as it was completed in July, 1900, with
no attempt to consider literature which may have appeared since that
time. The only additional matter in the body of the paper is that in the
foot notes, and concerns the publication of Eycleshymer and Wilson above
referred to, whose results are in several respects at variance with our own.
Some titles have been added to the literature list—J. R.

(469)

470 REIGHARD—PHELPS. [Vou. XIX.

penser, and Lepidosteus. This study has necessarily involved
some consideration of the head mesoblast.

We shall distinguish two phases in the history of the ad-
hesive organ: first a progressive phase which extends from
the origin of the organ to a stage of the larva shortly after
hatching, at which time the organ becomes functional, and
second a retrogressive phase which extends from the close
of the functional period to the time of the entire disappear-
ance of the organ. In considering each of these phases we
shall have occasion to refer to certain stages in the develop-
ment of the embryo and larva, but shall describe these stages
only in sufficient detail to render possible their subsequent
identification.

THE PROGRESSIVE PHASE.

The first stage.* a. The Adhesive Organ. The first ex-
ternal indication of the adhesive organ is found in embryos
which still lie flat on the yolk (Plate, Fig. 1), with neither
head nor tail protuberant. The brain at this stage shows
externally two divisions. only. The limits of the hindbrain
are not distinguishable, but near its anterior end it appears

*This early stage of the adhesive organ has been found in surface views,
only in embryos preserved after removal of the egg membranes or by a
method which does not cause shrinkage of the membranes. If the eggs are
preserved without such precaution shrinkage of the membranes brings
them into contact with the surface of the embryo, obliterates many exter-
nal features, changes topographic relations, and deforms certain internal
structures. The sections figured by Eycleshymer and Wilson (1908, early
stages) show the membranes still in situ and shrunk against the embryo.
The use of such material probably accounts for their statement that the
adhesive organ appears as a pait of diverticula. Shrinkage of the mem-
branes obliterates the delicate “crescent” which is unpaired and includes
the adhesive organ. This should appear in Fig. 13, Pl. I, of Eycleshymer
and Wilson, 1906. They say that in embryos of ninety hours “the adhesive
organs are not observable in surface views” (1908, p. 135), and they figure
this stage without adhesive organ in Pl. I, Fig. 15, of their paper of 1908.
On the contrary, we find the organ well developed and paired in surface
views in a somewhat younger stage (cf. our plate, Fig. 2). Shrinkage of
the membranes obliterates these delicate surface features in early stages,
and gives rise to the impression that they appear only in later stages.

No. 2.] THE ADHESIVE ORGAN OF AMIA. 471

to be much broader. Opposite this broader part the audit-
ory pit is found in sections. The broadening itself is due
in part to the proliferation of cells from the ganglionic ridge.
The future anterior end of the hindbrain lies just anterior
to this broader portion. The pointed tip of the forebrain
extends beyond the optic vesicles which lie close on either
‘side of it and form the most conspicuous part of the head. On
each side, behind the optic vesicles and at the side of the brain
is an elevated, oval area, the branchial area, within which

~ div. arch.

ZROres
Hon LOB Beis
ch Seat ‘ Ol LL ap —

S
srt

oF 26) S Soro
Ce OB089 oI Oo RSs
Oo aS oO rej oYers:

Fic. A.—Part of a parasagittal section of an embryo along the curved line
a-b of the stage shown in Fig. 1. Camera outline drawing; details
from a photograph. div. arch., diverticulum of the archenteron (cres-
cent) ; ent., entoblast; i. ect., internal layer of ectoblast; o. ect., outer
layer of ectoblast; op. v., optic vesicle; ylk., yolk. The section passes
to one side of the median plane and does not include the hypophysis.

gill slits appear in a later stage. The axial mesoblast shows
in sections at least twelve trunk somites. In front of the
optic vesicles and lying against them and the anterior end
of the brain is a crescent-shaped, elevated area which 1s shown
by its subsequent history to include the fundament of the
adhesive organ. It will be referred to hereafter as the cres-
cent (anterior end of the foregut).

In a longitudinal section (Fig. A), the archenteron is seen
to be enlarged slightly at its anterior extremity to form a
broad, dorsally directed diverticulum which causes the cres-

472 REIGHARD—PHELPS. [Vou. XIX.

cent-shaped elevated area seen externally. The dorsal wall of
this diverticulum is made up of a single layer of columnar
entoderm cells, which are in contact with the nervous layer
of the ectoderm. Ventrally the cavity of the diverticulum is
bounded by the yolk from the surface of which a few cells
have been segregated. The cavity as seen in longitudinal
section is crescent shaped.

b. The Mesoblast—In the trunk region, and as far for-
ward as the midbrain region, the archenteric cavity is well
developed and extends across the middle line. In the an-
terior head region, however, the increased depth of the brain
causes the dorsal wall of the archenteron to be in contact
with the yolk in the middle line, and thus obliterates the
median portion of its lumen. The lateral portions of the
archenteric cavity in the anterior head region are, on the
other hand, well developed and connect the archenteric cavity
of the trunk with the cavity of the crescent which is thus
shown to be a part of the archenteron.

In an embryo a few hours younger than the one figured
the crescent is not readily visible externally,* but may be
easily found in sections. The columnar entoblast forming its
dorsal wall is found to be much thickened and many layered
at its anterior and lateral edges and to become there contin-
uous with the yolk. The crescent is thus terminated in front
and laterally by a germinal wall, much better developed later-
ally than in front. Posteriorly the crescent entoblast is con-
tinuous with the entoblast forming the dorsal wall of the
archenteron in the head region. This entoblast of the head
region is very thin in the middle line beneath the brain where
it is in contact with the yolk. On either side of the middle
line, however, it is many layered and very thick and is con-
tinuous laterally by means of a germinal wall with the yolk.
Thus in the head region in front of the hindbrain there is as
yet no mesoblast, but only the much thickened layer of ento-
blast continuous in front with the columnar entoblast of the
crescent. About the borders of this entoblast sheet and

*Such a stage is figured by Beckwith, 1907, Plate I, Fig. 1.

No: 2:] THE ADHESIVE ORGAN OF AMIA. 473

about the lateral and anterior border of the crescent ento-
blast there is a continuous germinal wall by which the ento-
blast passes into the yolk.

In an embryo of the stage represented in Fig. 1 this ento-
blast of the anterior head region has separated into two layers.
Of these the dorsal and thicker layer is composed of loosely
aggregated mesoblast cells, while the ventral layer is a colum-
nar entoblast, which forms the dorsal wall of the archenteron.
The mesoblast begins at a point just in front of the optic
vesicle, as a thick sheet of cells still connected with the ento-
blast near the median line, but free laterally. As the sheet
is traced backward it becomes broader. It retains its con-
nection with the entoblast near the median line and extends
thence laterally to the limit of the archentron, where it be-
comes continuous with the germinal wall. It is without a
cavity. The mesoblast of the anterior head region is thus
clearly formed by delamination from the entoblast. No meso-
blast is formed from the colwmnar entoblast of the crescent.

The second stage: a. The Adhesive Organ. The next
stage of the adhesive organ to be described is found in embryos
which show the following external features: The embryo
(Plate, Fig. 2) is still flat on the yolk; the midbrain is now
visible externally in addition to the forebrain and_ hind-
brain; the tip of the forebrain extends beyond the optic
vesicles for a short distance as in the preceding stage; the
recessus laterales are distinguishable in the hindbrain, so that
the cavity of the hindbrain may be described as triangular
in outline, the anterior lateral angles of the triangle forming
the cavities of the recessus laterales. Two oblique lines are
seen on each side within the branchial area. These are
gill slits. The first is the pre-hyoidean or spiracular slit,
which subsequently disappears. The arch behind it is the
hyoid arch. At its dorsal end the auditory vesicle is visible.
The crescent of the preceding stage has given place to
three hemispherical protuberances which are nearly as promi-
nent a feature of the head as the optic vesicles in front
of which they lie. The two lateral of these protuberances

474 REIGHARD—PHELPS. [Vor. XIX.

form the fundaments of the adhesive organ. ‘The central and
smallest of them lies in the middle line between the other
two and directly in front of the forebrain. It will be spoken
of as the button. Bounded outside by a curved white line,
and inside by the branchial area, are seen the halves of the
body cavity extending backward over the yolk about the
sides of the head. Between the three protuberances and the
white line the stomodaeum appears as a long crescent-shaped
depression.

pe. dix.

Fic. B.—Portion of a parasagittal section of an embryo of the stage
shown in Plate, Fig. 2. The section passes to one side of the
median plane through the optic vesicle and one-half of the adhesive
organ. Camera outline; details from photograph. X about 150. f. g.,
foregut; h., heart; i. ect., inner layer of ectoblast; 0. ect; outer layer
of ectoblast; op. v., optic vesicle; pc. c., pericardial cavity; pd. div.,
one of the paired diverticula of the foregut (fundament of the ad-
hesive organ); st., stomodaeum; ylk., yolk.

Sections of embryos of this stage (Fig. B) show that the
entoderm in front of the crescent has been folded backward
so as to form a small part of the ventral and side walls of
the foregut at its anterior end. Ventral and anterior to the
lower foregut wall thus formed and filling the entoderm fold,
is the large pericardial cavity within which is seen the heart.
Ventral to the pericardial cavity lies a portion of the yolk

No. 2.] THE ADHESIVE ORGAN OF AMIA. 475

sac which separates the entoblast beneath the pericardial
cavity from the yolk. The broad, flat, anterior end of the
foregut extends forward to the stomodaeum where its greatly
thickened anterior wall is-in contact with the ectoblast.
From the dorsal wall of the short foregut rise three diver-
ticula. The central one (Fig. C, med. div.) is thick-walled,
with a very shallow cavity and forms the button. The lateral

f, br.

Oke) Blog| Da
gee Ras
<i 59
IO 8 55S

is

Fic. C—Median longitudinal section of an embryo of the stage shown
in Plate, Fig. 2. Camera outline, details from photograph, * about
150. med. diy., median diverticulum which produces the “button”
seen in front of the forebrain between the paired diverticula in
Plate, Fig. 2. Other letters as in Figs. A and B. The hypophysis,
hy., is not accurately represented.

diverticula are also thick-walled, but have long and narrow
cavities. They leave the foregut at a point some distance from
the middle line, ventral and anterior to the tip of the fore-
brain, and pass upward, backward and outward, so that their
free ends touch the sides of the forebrain immediately in
front of the optic vesicles (Fig. B). These paired diverticula
produce the rounded protuberances referred to above as the
fundaments of the adhesive organ. The button and the ad-
hesive organ have evidently been formed from the crescent
of the preceding stage. The button may be considered as a
remnant of the central portion of the original crescent.

476 REIGHARD—PHELPS. [Vou. XIX.

The single layer of cubical cells making up the posterior part
of the dorsal wall of the foregut gives place to high columnar
cells in the walls of the adhesive organ fundaments. The pro-
toplasm of the peripheral end of each of these cells has em-
bedded in it large conspicuous yolk granules and the nucleus
with its prominent nucleoli also lies here, while the central
end is largely composed of mucus (?) surrounded by a thin
layer of protoplasm (Fig. B).

The planes passing through the long curved axis of the
two adhesive organ fundaments are not coincident with each
other, and if projected would intersect behind the optic vesicles
at an acute angle. The space between these fundaments on
the one hand and the forebrain and foregut on the other
hand is wedge-shaped and filled with loose mesenchyme. The
fundaments of the adhesive organ are in close contact with
the ectoderm, without intervening mesenchyme.

The relations of the diverticula and foregut are shown in
diagram in Fig. D.

Fic. D.—Diagram of the foregut and its diverticula seen from the dorsal
side in the stage shown in Plate, Fig. 2. The paired diverticula
(adhesive organ) are shown displaced backward. The broken line
indicates cavities: a, that of the button; b, that of the adhesive or-
gan fundaments. The solid lines indicate outer surfaces; c, that of
the adhesive organ; d, that of the button; e, the stomodaeum. The
line composed of dots and dashes shows the posterior limit of the
ventral wall of the foregut.

b. The Mesoblast. In the preceding stage the mesoblast
sheets of the head, when traced forward, were found to be-
come narrower and to end just in front of the optic vesicles.
In the present stage the mesoblast extends forward at the
sides of the adhesive organ and in front of the stomo-
daeum where it is continuous across the middle line.

No. 2.] THE ADHESIVE-ORGAN OF AMIA. 477

The pericardial cavity has developed in this mesoblast
sheet and may be seen in Plate, Fig. 2, extending backward
between the outermost white line on the yolk and the branch-
ial area to become continuous with the body cavity further
back. Mesoblast also occupies the space between the ad-
hesive organ and button on the one hand and the optic ves-
icles and brain on the other (Fig. B, mes.). Examination of
intervening stages shows that the mesoblast of the region an-
terior and lateral to the adhesive organ has been produced,
largely if not wholly, by progressive forward differentiation
from the germinal wall. This germinal wall extends along
the borders of the entoblast of the head and trunk region and
forward along the lateral and anterior borders of the colum-
nar entoblast of the crescent. The germinal wall of the
lateral borders of the crescent is especially well developed
and from it the mesoblast extends outward and also inward
and backward toward the head, until it becomes finally contin-
uous with the mesoblast previously formed in the head region.

The mesoblast at the anterior end of the brain and optic
vesicles and between them and the adhesive organ and button
owes its crigin in part to proliferation from the button. The
middle portion of the posterior surface of the button is in con-
tact with the hypophysis (Fig. C) and no mesoblast «is pro-
liferated from this portion of its surface at this stage. At
the sides of the hypophysis on the other hand the entoblast
of the button may be seen to be in process of transformation
into mesoblast. Cells here separate themselves from the but-
ton and at the same time assume the form of stellate mesen-
chyme. The whole button is thus finally affected so that by
the next stage it is no longer recognizable. The crescent
has given rise not only to the adhesive organ, but to a
considerable amount of mesoblast which is proliferated from
that portion of the germinal wall forming its borders as well
as from the button. The mesoblast of the head is then seen
to be formed principally by delamination from the primi-
tive entoblast, but partly also by proliferation from the cres-
cent in the manner just indicated.

478 REIGHARD—PHELPS., [VoL. XIX.

c. The head cavity. In this stage the mesoblast of the head
is mostly mesenchymatous, but extending forward from the
anterior end of the recessus lateralis on each side, beneath the
optic vesicle to its anterior border is a plate of more compact,
delaminated mesoblast about 70 microns broad and 30 microns
thick. It is connected across the middle line with the plate of
the other side by a solid cord of cells which lies in the saddle
cleft just behind the infundibulum and in contact with the front
end of the notochord. ‘These cell plates are surrounded by
loose mesenchyme except at the ends. The anterior end of
each continues into a slender cord of more compact mesoblast
which connects it with the germinal wall at the sides of the
adhesive organ. The posterior end of each is continuous with
a similar cell cord which extends backward to the recessus
lateralis and beyond it. Each of these plates contains a well
defined cavity whose form is the same as that of the plate
itself and whose extent is nearly as great. The cavities do
-not extend into the connecting cell cord. The dorsal wall of
each cavity is formed of columnar cells which are highest
toward its caudal end; the cells of the ventral wall are more
flattened.

The third stage; a. The Adhesive Organ. In this stage
the embryo, measured from the tip of the forebrain to the
end of the tail (Plate, Fig. 3), encloses about two hundred
and twenty degrees of the circumference of the yolk. The
tail is protuberant, but so slightly that the re-entrant angle be-
tween its ventral surface and the surface of the yolk is obtuse.
The midbrain is larger and the recessus laterales extend further
forward than in the second stage. The lines indicating the
gill pouches have changed their relative position so that they
lie close to the recessus laterales, and the anterior pair is less
marked than formerly.

As seen externally the adhesive organ has changed its forna.
In place of the two protuberances of the last stage we find two
kidney-shaped ridges, the concavities of which face each
other, and the median plane (Plate, Fig. 3). This gives
the adhesive organ as a whole the form of a broad ring

—-

No. 2.] THE ADHESIVE ORGAN OF AMIA. 479

interrupted dorsally and ventrally. Its form is therefore
similar to that seen in the embryo at the time of hatching
(Plate, Fig. 4), but its surface is not yet marked by the
pits characteristic of the hatching stage. The median button-
like protuberance is no longer visible.

In section the paired diverticula are seen to open wide as
before into the foregut. They are longer and more sharply
curved than in the preceding stage. We may distinguish for
each diverticulum two surfaces, an anterior and a posterior
and two borders, a conxev outer and a concave inner (Plate,
ies .3)2) Vhe-planes.-of the long -curved “axes ol the
diverticula, which before intersected, have rotated so as to
make them coincident with each other. This common plane
meets the frontal plane of the embryo at an obtuse angle;
that is the dorsal ends of the diverticula are posterior to the
ventral ends. The changed relations of the planes have re-
sulted, apparently, in carrying the dorsal ends of the diver-
ticula forward so that they no longer touch the forebrain.
This rotation has also changed their relation to the ecto-
derm. In the preceding stage the convex border of each
diverticulum was directed nearly forward and the diver-
ticulum was in contact with the ectoderm over the middle
portion of this border, so that there was produced a rounded
protuberance of the external surface. In the present stage,
owing to the rotation of the diverticula, the convexity ot each
is directed laterally, while the anterior surface, which before
faced the median plane, is directed forward and pushes up
the ectoderm with which it is in contact. There is thus pro-
duced, on each side, one of the low, rounded, U-sliaped
ridges referred to as visible externally (Plate, Fig. 3).

The nasal plates appear in sections of this stage. They are
mere thickenings of the ectoderm which in Amia consists of
an outer layer of flat cells and an inner layer of cubical cells.
Only the inner, nervous layer is concerned in the formation
of the nasal plates which lie near the median line just above
the adhesive organ and in close contact with it. It is often
hard to determine in longitudinal section the line of demarca-
tion between the two structures.

480 REIGHARD—PHELPS. [Vov. XIX.

b. The Mesoblast and the Head Cavities. The walls of the
head cavities are but little altered. The cavities themselves
are of about the same extent in a transverse direction as be-
fore, but have increased about three times in dorso-ventral
extent. The dorsal wall of each is still composed of colum-
nar cells, the ventral wall of flattened cells. In one specimen
of this stage, although the cavity was continuous on the left
side, it consisted on the right side of three isolated cavities
contained in the common sheet of mesoblast. The posterior
of these was the largest. It is probable that several small
isolated cavities are formed on each side and that these subse-
quently fuse into the single head cavity.

The head cavities of the two sides now extend for some
distance on each side into the connecting cell cord, but the
middle part of the cord is still solid. The walls of the head
cavities are separated from the structures anterior to them
by loose mesoblast; that is the compact cell cord connecting
them with the germinal wall in front is being transformed
into mesenchyme. Posteriorly they are still continuous with
the compact mesoblast which extends along the sides of the
neutral tube backward to the auditory vesicle.

The fourth stage is one in which the embryos agree closely
in external appearance with those of stage three (Plate,
Fig. 3). The tail is more protuberant than in stage three,
and the re-entrant angle beneath it acute. The only differ-
ence noted in the brain is in the greater length of the re-
cessus laterales. The hyoid arch has become prominent and
causes the second pair of gill pouch lines to be less marked.
The pre-hyoidean pouches are not visible. The adhesive organ
shows no external change, except that the plane of the two
diverticula is nearly at right angles to the frontal plane
instead of being at an obtuse angle as in stage three.

The further step in the development of the organ which
has been taken since the last stage is one which is observable
only in section (Fig. E). The lumen of each diverticulum
is no longer of uniform diameter but shows a series of dila-
tations connected by narrower portions. These give to the

No. 2.] THE ADHESIVE ORGAN OF AMIA. 481

lumen a beaded appearance. The diameters of the narrower
and wider portions are to each other as one to five or six.
On the anterior face of the organ there are no grooves cor-
responding to the constrictions of the lumen, but on the pos-
terior face a few such grooves are found. Each of the dila-
tations marks the fundament of a closed spherical vesicle, and
each diverticulum is found to break up subsequently into as

Fic. E.—Longitudinal section passing through one of the halves of the
adhesive organ of an embryo of a stage a little later than that shown
in Plate, Fig. 3. Lettering as in the preceding figures. The por-:
tion of the adhesive organ seen in the figure shows three dilatations
of its cavity. The central one is not cut through its middle, and is
therefore not well marked. Camera outline, details from photograph.
< about 170.

many such vesicles as there are dilatations formed in its lumen
at this stage. The head cavities are but little changed from
the preceding stage.

The fifth stage; a. The Adhesive Organ. Yrom the fourth
stage to the fifth or hatching stage, the adhesive organ passes
through a series of progressive changes which cannot well
be described separately. There will be given first an account
of the conditions at the time of hatching and then an analysis

482 REIGHARD—PHELPS. [Vor. XIX.

of the processes which have led up to these conditions. At
the time of hatching the embryo® is about seven millimeters
long (Plate, Fig. 4). The most conspicuous change that
has occurred in the brain is the great increase in the size
of the midbrain and its division into two lobes. No gill
slits are visible externally. The prehyoidean slits have dis-
appeared and the hyoid arches now extend backward as nar-
row opercula so as to cover the second pair of gill slits and
all others that have formed behind it. The pigment cells
which are a conspicuous feature of this stage lie thickest in
the region of the auditory vesicles. They extend for a short
distance along the lateral lines posteriorly, and arch over the
optic vesicles anteriorly. No pigment is observed on the
adhesive organ or in its vicinity. The stomodaeum and
pharynx are in communication.

The adhesive organ at this time consists of two sausage
or U-shaped ridges which have the same position as in stage
four (Plate, Fig. 3), Each sidge is made up lof a semies
of six to ten cups whose cavities open to the surface so that
they are seen from the exterior as pits. The dorsal ends
of the ridges touch each other in the median plane while the
ventral ends, still wide apart, abut on the roof of the stomo-
daeum, and thus help to form the dorsal border of the mouth
opening. Indeed the ventral ends of the ridges run back
along the roof of the mouth for a short distance. The planes
of the ridges remain at right angles to the frontal plane as
in stage four. Sections of the embryo at the hatching stage
show that the lumen of the cesophagus is obliterated and that
there is no longer any communication between the adhesive
organ and the foregut. A longitudinal section taken just
at one side of the median plane cuts through both limbs
of one of the curved ridges of the adhesive organ. If the
section falls through the center of one of the cups, a pit-like
cavity appears which opens at the surface and is surrounded
by thick walls made of a single layer of exceedingly high

Por a lateral view of an embryo in this stage, see Beckwith, 1907,
1 Po) WO) Eel a eb hae

No. 2.] THE ADHESIVE ORGAN OF AMIA. ' 483

columnar cells (Fig. F). The central ends of these cells
next the cavity of the cup are distended, apparently with
mucus. The peripheral third of each cell stains heavily on
account of the larger amount of yolk it contains. The nucleus
also lies in the peripheral portion of the cell. The walls of the
cups are continuous at their edges with the adjacent ectoblast,
so that the cups have the appearance of being thickenings of
the ectoblast. Fig. F, which shows a film-like layer of ecto-
blast closing the mouth of the cup, belongs to a slightly earlier
stage, but represents fairly the structure at the hatching stage.

~-- W. VS.

Fic. F—Section through one of the vesicles of the adhesive organ of an
embryo of Amia a little younger than that shown in Plate, Fig. 4.
c. vs., cavity of the vesicles; w. vs., wall of the vesicle. Other let-
ters as in preceding figures. The inner layer of ectoblast has dis-
appeared over the cavity of the vesicle, but the outer layer still
remains,

During the interval between the fourth and hatching stages
important and rapid changes are thus seen to have taken
place in the adhesive organ: First—Each fundament has been
divided into as many vesicles as there were dilatations of
its lumen in stage four. This division has resulted apparently
from an extension and deepening of the grooves, present in
stage four on the posterior faces of the diverticula, but the
precise method of this process is unknown. The result is that
each of the dilatations of stage four becomes the cavity of

484 REIGHARD—PHELPS. iWon, akc

one of the vesicles, while the cells composing the walls of
the original diverticulum now form the walls of the vesicles.
Six to ten such vesicles are formed on each side.

Second—Subsequently the cavities of the vesicles shift their
position so that they come to lie excentric, close against the
ectoderm of the snout. The vesicles are thus converted into
cups whose mouths are still closed by the ectoderm (Fig. F).

Third—At the time of hatching, or just previous to it, the
ectoderm stretched over the mouths of the cups disappears
and their cavities are put into communication with the ex-
terior. The edges of the cups become thus continuous with
the adjacent ectoblast and the cups themselves have the ap-
pearance of being thickenings of the ectoblast. At first the
cavities are ovoid or spherical, later they become shallower
and their openings wider.

The processes described above as converting the beaded
diverticula of stage four into the open cups of the hatching
stage bring the organ to its functional condition, and the
secretion of mucus enables the young Amia to adhere to
objects with which it may come into contact.

b. The Mesoblast and Head Cavities. The head cavities
are now greatly enlarged and have the form of large sacs
which lie in the triangular space between the tweenbrain, optic
vesicle and foregut and conform to it. The cord of cells con-
necting them is converted into a tube with a wide lumen. It
lies in the saddle cleft dorsal to the infundibulum. The walls
of the cavities are of cubical or slightly flattened cells. At
one point they are greatly thickened and connected with the
third nerve.

These head cavities from their position, their connection
across the middle line by a tube which lies at the front end
of the notochord and by their relation to the third nerve are
clearly equivalent to the premandibular head cavities of elas-
mobranchs, reptiles and birds. Their further history has not
been traced, but it is to be expected that they give rise to the
oculomotor muscles as in other vertebrates. They are formed
in the sheet of mesoblast which is delaminated from the

No: 25] THE ADHESIVE ORGAN OF AMIA. 485

primitive entoblast of the head region. They are formed
therefore in situ. We have traced their origin step by step
and have found no evidence of their being produced by
evagination from the entoblast as described by v. Kupffer
(1893) in Acipenser. We consider such a method of origin
impossible for Amia. No trace of a second head cavity has
been found.

Il. THE RETROGRESSIVE PHASE.

In larve 15 mm. long the adhesive organ as seen from the
surface is in the condition figured by Allis (1889), Fig. 11.
Its ring-shaped form still persists but it is not sharply outlined.
It is much reduced in actual size and lies close above the
mouth opening in the middle line, with the nasal openings on
either side of it and slightly above it. The outlines of the
individual cups composing the organ are still visible. The
lateral line canals show distinctly.

Sections of such larve and of slightly younger ones show
the epidermis over the end of the snout to be much thickened
and filled with pigment cells and sensory buds. Beneath it
are the regularly arranged lateral line organs. The cups of
the adhesive organ are found to be still connected with the
exterior, but the great thickening of the ectoderm has con-
verted their openings into deep narrow tubes. The cells
which make up the walls of the vesicles have the appearance of
being greatly elongated. Their central ends are still filled
with mucus, but the protoplasm of their peripheral ends con-
tains a few vacuoles.

In larve varying in length from seventeen to eighteen milli-
meters the only external evidence of the adhesive organ is a
small median opening lying at the apex of the upper jaw (Fig.
G). This opening is at first slit-like and parallel to the edge
of the jaw, later it becomes circular and resembles closely: the
opening of a lateral line organ. By means of sections one
finds that the much thickened ectoderm entirely covers the
adhesive organ except at this opening (Fig. G). The semi-
circular halves of the organ have the appearance, as seen in

486 REIGHARD—PHELPS. [Von scies

section — they are not visible from the exterior — of hav-
ing been flattened dorso-ventrally so that the two limbs of
either curved row of cups lie parallel to one another and close
together. The four ends of the two rows are thus brought
together and the four median cups (lying at the ends of the
rows) are in contact with one another. ‘These four cups open

Fic. G.—Longitudinal (sagittal) section of the tip of the upper jaw of an
18 mm. larva of Amia, showing the adhesive organ in a late stage of
degeneration. Camera outline drawing, about 170. adh. org., ad-
hesive organ; ect., ectoderm; 1. 1. org., lateral line canal; mes.,
mesenchyme; pg. c., pigment cell. s. b., sense bud; s. mx., cartilage

of the upper jaw.

to the exterior through a common aperture, the median open-
ing spoken of above, while the remaining cups no longer com-
municate with the exterior.

The cups have lost their original spherical shape and there
is a tendency for them to open into each other. The degen-
eration of the organ appears to have begun at the sides and
to have proceeded toward the median plane. The boundaries
of the organ are still perfectly definite and the cells have the

No: 2] THE ADHESIVE ORGAN OF AMIA. 487

sae general arrangement that they had before the degenera-
tion began. There is no yolk present and the entire contents of
the cells are therefore much more transparent than formerly.
The nuclei have the same peripheral position as before, but
the central ends of the cells are no longer distended with
mucus; the goblet character is not retained. Stellate mesen-
chyme cells crowd close about the organ on all sides, separat-
ing it from the superior, maxillaries which lie immediately
back of it, from the lateral line canals which lie deep below

Jes
6

ae:
PW)

Sece

SS
2

Fic. H.—Longitudinal section of the tip of the upper jaw of a 20 mm.
larva of Amia with adhesive organ in final stage of degeneration.
Camera outline, & about I50. Ic., leucocytes. Other lettering as in
Fig Io.

the surface, and from the epidermis except at the point where

the epidermis dips down to form the tunnel through which

the four median cups communicate with the exterior. Here,
in the walls of the tunnel, the cells of the adhesive organ are
continuous with the cells of the epidermis.

This tunnel is not a single, simple tube, but is divided just
below the epidermis into two lateral branches, one of which
goes to each half of the adhesive organ. Each of these
branches is also bifurcated so that there are formed in al! four

4&8 REIGHARD—PHELPS. [Vou. XIX.

branches, which open one into each of the four median cups.
The thickened epidermis is filled with pigment. Numerous
sense buds also occur in it and through it the lateral line
canals open to the exterior.

When the larva reaches 20 mm. in length (Fig. H), the
median opening of the adhesive organ has disappeared and
there is no external sign of the organ; but in sections (Fig.
H1) it is found to exist as a pair of irregular ovoid masses,
one mass lying on either side of the median plane beneath the
much thickened epidermis. The central portion of each of
these is made up of an extremely vacuolated central mass, the
remains of the central portions of the cells of the former
cups. A few leucocytes occur among the meshes of the spongy
core, surrounding which is a relatively thin sheet or layer
which takes the stain heavily. It is evidently made up of the
remnants of the peripheral ends of the cells of the former
cups and contains the nuclei and all that is left of the proto-
plasm of these cells. The whole structure bears histologically
a strong resemblance to the notochord in certain of its stages.
This outer, deeply stained covering is wanting on the ante-
rior faces of the ovoid masses where a median neck of ecto-
derm connects the two masses with the epidermis. This neck
of ectoderm marks the position of the tunnel which led from
the adhesive organ to the exterior in the 18 mm. larva. As
the epidermis has thickened the tunnel has become entirely
closed. A few days later no trace of the adhesive organ is to
be found.

SUMMARY OF OBSERVATIONS.

1. The adhesive organ of Amia is an entoblastic structure
which is developed from an unpaired fundament as a pair of
curved cylindrical diverticula of the foregut. Each diver-
ticulum subsequently loses its connection with the foregut
and breaks up into six to ten closed vesicles. Each vesicle
then acquires an opening at the surface and becomes thus con-
verted into a cup continuous with the ectoblast.

No. 2.] THE ADHESIVE ORGAN OF AMIA, 489

2. The ends of the cells of the cups next their cavities form a
secretion (mucous?) by which the organ is rendered adhesive.

3. In larve 18 or 20 mm. long the adhesive organ has been
pushed beneath the surface by the thickening of the epidermis.
Its cells subsequently become vacuolated, leucocytes appear
among them and the organ finally wholly disappears.

4. There is at no time any genetic connection between the
adhesive organ and the ectoderm, or any of the epidermal
sense organs; nor is there more than a superficial resemblance
between it and any of the epidermal sense organs.

5. Ihe mesoblast of the head region is formed largely by
delamination from the entoblast, but part of it is proliferated
from the germinal wall bordering the crescent and part from
the “button” (pre-oral gut).

6. A pair of head cavities is formed in the delaminated
mesoblast and these later communicate with one another
across the middle line. The communication lies in the saddle
cleft at the front end of the notochord.

7. The head cavities are not formed by evagination from
the archenteron, but appear in situ in the mesoblast. They
are equivalent to the premandibular head cavities of other
vertebrates and become later connected with the third nerve.

CONCLUSIONS.

An adhesive organ occurs in the larve of Amia, Lepidos-
teus and Acipenser, and in certain Amphibia. What we be-
lieve to be a homologous structure is found in Elasmobranchs
and in Amphioxus. We shall not discuss the Amphibian
organ at this time.

Amia. Dean, in his work on the larval development of this
form (1896), says that in the four-day larva the two halves of
the adhesive organ are crossed transversely by a row of pig-
ment cells which “apparently demarcate the lines of the sen-
sory tracts.’ This existence of pigment across the adhesive
organ as well as along the sensory tract is regarded as evi-
dence that the cups of the adhesive organ are homologous to

490 REIGH ARD—PHELPS. [Vor. XIX.

the sense organs of the tracts. Dean finds further evidence
for this homology in the structural resemblance of the two
organs. He says: “As far as histological evidence goes there
is certainly no difference between the enlarged, thick-walled,
cup-shaped organs which arise on the snout of the late em-
bryos of Amia or of Lepidosteus and the typical pit organs
or sense buds which later occur on other integumental regions.
It is found, in fact, that a gradation in size exists which con-
nects the huge sucking organs of the snout with the incon-
spicuous organs of the trunk.”” In a note he adds: “There
is but little difference histologically between these (1. €. the
cup-shaped organs of the adhesive disc) and the neighboring
nasal pit.”

Dean’s inference that the existence of pigment across the
adhesive organ indicates the homology of its constituents with
the organs of the pigmented lateral line, need not detain us.
There remains the histological resemblance of the two struc-
tures which he believes to indicate their homology.

Such similarity as exists is apparent only and depends
wholly on the plane of section. Thus certain sections cut
transversely through the peripheral ends of the cells of the
adhesive organ cups, resemble sections of the nasal pits lying
against the adhesive organ and cause the two to be easily
confused. But when the whole series of sections is examined,
and sections cut in other planes are compared, the differences
are much more striking than the similarities. The goblet cells
of the cups of the adhesive organ can hardly be long mis-
taken for the cells of pit organs. - The presence of yolk in the
entoderm cells aids in distinguishing ectodermal and ento-
dermal tissue in this case as in others.

All histological differences aside, the development of the
adhesive organ from entodermal pouches, and its entire dis-
appearance make it impossible for any genetic connection to
exist between the adhesive organ and the epidermal sense
organs in Amia.

Lepidosteus. Alexander Agassiz (1879) first called atten-
tion to the adhesive organ in this form and Balfour (1881)

No. 2.] THE ADHESIVE ORGAN OF AMIA. 491

subsequently considered its constituent papillz as “thickenings
of the epiblast” and says: “These papilla are probably sensi-
tive structures, but I have not yet investigated their histo-
logical characters.” Balfour and Parker (1882) subsequently
considered the organ as composed of mucous cells, which were
highly modified cells of the mucous layer of the epidermis.
These cells they believed to pour out a sticky secretion. In-
vestigations now in progress in this laboratory, which it is
hoped shortly to publish, have shown that the adhesive organ
of Lepidosteus has essentially the same developmental history
as that of Amia. There is as little ground for considering
its papilla to be either ectoblastic or sensory as in the case
of Amia.

Acipenser. Von Kupffer (1891) describes an organ which
he calls the adhesive organ. It arises as-a cushion-like thick-
ening of the nervous layer of the ectoblast immediately dorsal
to the stomodeum. The organ, as figured externally (v.
Kupffer, 1891, Pl. 1), has somewhat the form of a crescent
with enlarged ends which point dorsally. The convexity of
‘the crescent lies just above the roof of the mouth. Three
days after hatching the adhesive organ separates into two
parts which have the form of hemispherical protuberances
separated by the cleft-like space between the medial ends of
the superior maxillary processes. Later each of the two parts
of the adhesive organ thus formed again divides into two,
so that there are four spherical projections which lie in a
slightly curved row above the upper jaw. These become the
four barbels of the adult.

In view of what we now know of the adhesive organ of
Amua that of Acipenser should be re-investigated, especially
since v. Kupffer did not pay especial attention to it. He points
out that, although the external ectoderm and the ectoderm of
the brain are free from yolk, yet the cells of the hypophysis
and adhesive organ are filled with the same yolk materials as
those of the entoderm, thus making it impossible to distin-
guish the tissues of these organs from the entoderm by means
of stains. This presence of yolk indicates an entodermal

402 REIGHARD—PHELPS. [Von. XIX.

origin for the adhesive organ. A further suggestion con-
cerning a possible homologue in Acipenser of the Amia ad-
hesive organ will be found in a paper on the development of
the hypophysis of Amia, by Reighard and Mast (1908).

Elasmobranchs. lf we regard the adhesive organ of Amia
as a pair of entoblastic pouches from the anterior end of the
foregut it becomes an interesting question as to whether there
exist in other vertebrates similar gut pouches with which they
may be compared. The head cavities of Elasmobranchs at
once suggest themselves. We have shown that in Amia the
first head cavities (pre-mandibular) are formed in the meso-
blast of the head behind and beneath the optic vesicles. If
then the adhesive organ of Amia be comparable to a pair of
head cavities it must be to that pair which lies in front of the
pre-mandibular cavities, that is to the anterior head cavities of
Platt.

The anterior head cavities were first described by van
Wijhe (1882) in Galeus and later in much more detail by Platt
(1891, 1891a), Hoffmann (1896) and Neal (1898) in Acan-
thias. According to the last three observers the foregut ex-
tends in early embryos nearly or quite to the anterior neuro-
pore, (Hoffmann, Pl. III, Fig. 19, z, embryos with 15-20
somites). Hoffmann describes this ‘pre-oral gut’ as becoming
subsequently divided by the down-growth of the infundibulum
into a median and two lateral parts. The lateral portions lie
beneath the optic vesicles and are for a time connected with
one another by the median portion which extends from the in-
fundibulum nearly to the neuropore. The median portion of
the pre-oral gut breaks up finally into mesenchyme. The
lateral portions develop cavities and become the anterior head
cavities. After a time the proliferation of cells from the walls
of these cavities renders them solid. Still later they break
up into mesenchyme (embryos of 22 mm.) and are no longer
distinguishable from surrounding mesenchyme.

The anterior end of the foregut of Amia forms a ‘pre-
oral gut’ (cf. Fig. C). This becomes divided into three por-

No. 2.] THE ADHESIVE ORGAN OF AMIA. 493

tions. The central one of these, the “button,” subsequently
breaks up into mesenchyme, as does the middle portion of the
pre-oral gut of Elasmobranchs. The lateral portions exist
as diverticula of the ‘pre-oral gut’ (fundaments of the ad-
hesive organ). Their relation to the foregut and to the optic
vesicles and ectoblast is precisely the same as the relation of
the anterior head cavities of Elasmobranchs to the same struc-
tures. This is at once evident upon comparing our figure B
with Neal’s Figs. 7 and 8, Pl. III. These lateral diverticula
of the foregut of Amia differ from the anterior head cavities
of Elasmobranchs in their larger size and in the fact that
their lumina communicate with that of the foregut. These
differences are referable to the fact that in Amia the diver- °
ticula are functional, becoming converted into an adhesive
organ. In the Elasmobranchs the anterior head cavities are
not functional as organs, but become converted into mesen-
chyme. They are potentially diverticula of the foregut. They
are furthermore in process of reduction, as shown by the fact
that, while they are still of considerable size in Acanthias
(Platt, Neal, Hoffmann) and in Galeus (van Wijhe), they
are much reduced in Scyllium (van Wijhe) and are apparently
absent in other Elasmobranchs. In these other Elasmobranchs
the pre-oral gut probably breaks up directly into mesenchyme,
without first forming the anterior head cavities.

It seems to us that there can be but little doubt that these
anterior head cavities were formerly much better developed
in Elasmobranchs than they now are, and that they were then
formed as diverticula of the foregut. According to Platt
(1891) this method of formation still obtains, though this is
emphatically denied by Neal. We believe these diverticula
to be homologous with the adhesive organ of Amia. It is
most probable that the anterior head cavities represent an
adhesive organ that formerly existed on the end of the snout
in developing Elasmobranchs. An adhesive organ of the char-
acter of that of Amia is of use only to larve of relatively small
size like those of Ganoids and Amphibia. With increase in size
of the larva the organ becomes useless owing to its inability

494 REIGHARD—PHELPS. [ Vou: axis

to support the increased weight. Assuming that such an in-
crease in size has come about in Elasmobranchs through yolk
accumulation, the adhesive organ of these forms has conse-
quently become useless and has been reduced. It persists in
but three genera in the form of the anterior head cavities.

Since an adhesive organ of this form is useless to a larva
greatly burdened with food yolk, its retention in Ganoids indi-
cates that the ova of these fishes have not at any time pos-
sessed more food yolk than they now have. The Ganoid ovum
is not to be derived from that of the Elasmobranch through
secondary reduction in the amount of food yolk. Beard’s
(1890) contention on this point is thus upheld. Hence we
must conclude that the Ganoid and Elasmobranch lines sep-
arated before the great accumulation of yolk in the ova of
Elasmobranchs had taken place.

Amphioxus. Here there is found a pair of diverticula at
the anterior end of the foregut. Of these anterior gut
pouches the right becomes the head cavity of Amphioxus,
while the left acquires an opening to the exterior and is finally
converted into the Raderorgan, a lobed tract of ciliated epi-
thelium which surrounds the mouth. The left anterior gut
pouch of Amphioxus thus agrees with the adhesive organ of
Amia in opening to the exterior. Neal (1898) has already
homologized these anterior gut pouches of Amphioxus with
the anterior head cavities of Elasmobranchs. If this be con-
ceded, they are in turn homologous to the adhesive organ of
Amia. The evidence at hand does not seem to us to warrant

any other conclusion, though possibly it does not warrant any
conclusion.

SUMMARY OF CONCLUSIONS.

The adhesive organ of Amia (and Lepidosteus) is in no
way homologous with epidermal sense organs as claimed by
Balfour (1881) and Dean (1896). It is a pair of gut pouches
comparable to the anterior head cavities of Elasmobranchs.
These anterior head cavities may therefore be interpreted as
adhesive organs which have been rendered useless by the in-

No. 2.] THE ADHESIVE ORGAN OF AMIA. 495

creased weight of the larva due to yolk accumulation and
have been consequently reduced. They are, in their turn,
probably homologous with the anterior gut pouches of Amphi-
OXUS.

We have in the adhesive organ of Ganoids an indication
that their eggs have at no time contained more food yolk
than at present, while the existence of a reduced adhesive
organ in Elasmobranchs indicates that the Ganoid and Elas-
mobranch lines separated before the accumulation of yolk in
the Elasmobranch ovum.

LITERATURE CITED.

AGassiz, ALEXANDER, 1879. The Development of Lepidosteus. Proc. Am.
Acad. Arts and Sci. (New Series), VI, 65.

Autts, E. P., 1889. The Anatomy and Development of the Lateral Line
System in Amia calva. Jour. Morph., II, 463.

Batrour, F. M., 1881. Comparative Embryology (See II, 91).

Batrour, F. M., AND Parker, W. N., 1882. Structure and Development
of Lepidosteus. Phil. Trans. Roy. Soc., Lond., II, 359-442. (Adhesive
organ, p. 385.)

Bearp, JoHN, 1890. The Inter-relationships of the Ichthyopsida. Ant.
Anz., V, 146-159 and 117-188.

BeckwitH, Cora J., 1907. The Early Development of the Lateral Line
System of Amia calva. Biol. Bull., XIV, 23-28, Plates I-III.

Dean, BAsHForD, 1896. The Larval Development of Amia calva. Zoolo-
gische Jahrbiicher, IX (see p. 639).

EycLtesHYMER, ALBert C., AND Witson, J. M., 1906. The Gastrulation
and Embryo Formation of Amia calva. Amer. Jour. Anat., V (2),
133-162, four double plates.

EycLesHYMER, ALBerT C., AnD Wirson, J. M., 1908. The Adhesive Organ
of Amia. Biol. Bull., XIV (3), 134-144, two plates,

HorrMan, C. K., 1896. Beitrage zur Entwickelungsgeschichte der Selachii.
Morph. Jahrb., XXIV, 209-286.

Kuprrer, C. von, 1891. Die Entwickelung des Kopfes der Kranioten, Heft
1, Die Entwickelung des Kopfes von Acipenser sturio, an Median-
schnitten untersucht.

Kuprrer, C. von, 1893. Die Entwickelungsgeschichte des Kopfes. Merkel
und Bonnet’s Ergebnisse, II, 501-564. (See pp. 516, et seq.)

Neat, H. V., 1898. The Segmentation of the Nervous System in Squalus
acanthias. Bull. Mus. Comp. Zool., XX XI, 7, 147-204.

Pratt, Jutta B., 1891. A Contribution to the Morphology of the Verte-
brate Head based on a study of Acanthias vulgaris. Jour. Morph.,
V, 79-112.

496 REIGHARD—PHELPS. [Vor Scie

Pratt, JuLtia B., 1891a. Further Contributions to the Morphology of the
Vertebrate Head. Ant. Anz., VI, 251-256.

PHELPS, JESSIE, 1899. The Development of the Adhesive Organ of Amia.
Science N. S., IX, 366.

PHELPS, JESSIE, 1900. The Origin and Development of the Adhesive Organ
of Amia calva (abstract). First Report Mich. Acad. Sci., 137-139.
REIGHARD, JACOB, 1902. On the Anterior Head Cavity of the Elasmo-

branchs. Third Report Mich. Acad. Sci., 81.

ReicgHARD and Mast, 1908. Studies in Ganoid Fishes. II. The Develop
ment of the Hypophysis of Amia. Journal of Morphology, Vol.
XX No.2

WiyHE, J. W. vAN, 1882. Ueber die Mesodermsegmente und die Entwicke-
lung der Nerven des Selachierkopfes. K.. Akad. der Wiss. zu Amster-
dam, XXII.

*1

EXPLANATION OF THE PLATE.

ad. org., adhesive organ.

a. p., auditory pit.

b. a., branchial area.

b. a. 1., first branchial arch.
b. c., body cavity.

bt., button (prae-oral gut).
cr., crescent (fundament of prae-oral gut and adhesive organ).
h. a., hyoid arch.

m. a., maxillary arch.

st., stomadaeum.

th., thickening of neural crest.

Fic. 1.—Dorsal view of an early embryo of Amia, showing the first
stage of the adhesive organ as part of a crescent-shaped elevated area.
The line a-b indicates the plane of the section shown in text figure B.
Description in text, p. 470. Drawn from a photograph. X 20.

Fic. 2.—Dorsal view of an embryo of Amia, showing the second stage
of the adhesive organ, as a pair of protuberances with the button between
them. Description in the text, p. 473. Drawn from a photograph. X 20.

Fic. 3—Ventral view of an embryo of Amia with the adhesive organ
in the third stage. Description in the text, p. 478. Drawn from a photo-
graph. X 20.

Fic. 4—Embryo of Amia at about the time of hatching. The embryo
is between six and seven mm. long. Ventral view. Description in the
text, p. 482. Drawn from a photograph. X 20.

THE ADHESIVE ORGAN OF AMIA PLATE |
REIGHARD AND PHELPS

JOURNAL OF MORPHOLOGY--VOL. XIX, NO. 2

STUDIES ON*GANOID-FISHES|
Il. THe DEVELOPMENT OF THE HYPpopHysiIs OF AMIA.

JacoB REIGHARD AND S. O: Mast.

In describing the origin and early development of the
hypophysis it is convenient to refer to definite stages in the
development of Amia, as designated in the preceding article
on “The Development of the Adhesive Organ and Head Meso-
blast of Amia.”’

By referring to Fig. I accompanying the article just
mentioned it will be noticed that there is a slight depression
between the anterior end of the neural tube and the adhesive
organ. This depression marks the position of the fundament
of the hypophysis. A median longitudinal section (Fig. 1)
through an embryo of this stage, shows the ectoblast to con-
sist of two layers. The outer layer is thin and quite uniform
in thickness. It is composed of a single tier of rounded
opaque cells which are slightly flattened. The inner layer,
also composed of a single tier of cells, approximately cubical
in form, is about as thin as the outer except over a consider-
able area in the region dorsal to the anterior end of the neural
tube, where it gradually becomes thicker from all sides, ex-
tends inward and becomes continuous with the walls of the
neural tube which at this point extend outward forming a
small funnel-shaped evagination in the dorso-anterior region
of the neural tube, or forebrain. A similar evagination is
designated lobus olfactorius impar by von Kupffer (1893)
in Acipenser. In the following description we shall, following
Haller (1897), speak of the tissues (Fig. 1, np.) between the

‘From the Zodlogical Laboratory of the University of Michigan, Ann
Arbor, Michigan, U. S. A.

(497)

408 REIGHARD—MAST. [Vov. XIX.

above-mentioned evagination of the forebrain cavity and the
exterior as neuropore (mediane Riechplatte and lobus olfac-
torius impar of von Kupffer).

Immediately in front of the neuropore the thickened por-
tion of the inner layer of the ectoblast becomes still thicker,
extending postero-ventrally in the form of the segment of a
sphere. (Eig) hye)

This is the fundament of the hypophysis. The ectoblast
of the neuropore and that of the hypophysial fundament are
thus seen to form parts of the same thickening of ectoblast.
The nervous or inner layer of the ectoblast anterior to
the fundament of the hypophysis as well as that on both
sides of it is composed of a single tier of columnar cells. In
the ectoblast which forms the fundament of the hypophysis,
the columnar cells, judging from the arrangement of the
nuclei, appear to have divided transversely, thus forming ap-
proximately cubical cells. The cell walls could not be seen
distinctly in the hypophysis in this stage, consequently it was
impossible to determine the exact form of the cells and their
arrangement. Some little distance anterior to the fundament
of the hypophysis, there is a broad, low, thick-walled evagi-
nation (Fig. 1, ad.) of the dorsal wall of the alimentary
canal near the anterior end. This is the crescent as described
in the preceding paper. Immediately in front of the crescent
there is a smaller but deeper evagination (Fig. 1, m.) marking
the position of the mouth opening. In the space between the
ventral surface of the hypophysis the dorsal wall of the
alimentary canal and the anterior wall of the forebrain there
is a mass of rather closely packed mesenchyme cells (Fig.
{ties

A median longitudinal section (Fig. 2) of an embryo cor-
responding in age to stage three (Fig. 6) of the preceding
article, shows that the fundament of the hypophysis which
formed a part of the inner layer of ectoblast in the preceding
stage, is now connected with other ectoblast tissue only at
its posterior or dorsal end where it is continuous with the
neuropore. It has become a solid rod of cells slightly flat-

No. 2.] THE AYPOPHY SIS OF AME. 499

tened. The original anterior end of the hypophysis is now
directed postero-ventrally and projects into the slightly acute
angle formed by the floor of the forebrain and the dorsal
wall of the alimentary canal. The posterior surface (ventral
surface of the preceding stage) comes in contact near its dorsal
end with the wall of the forebrain in the region of the lobus
olfactorius impar and near its ventral end with the wall of the
forebrain in the infundibular region (Fig. 2, in.). The cen-
tral portion of the posterior surface is separated from the fore-
brain by a mass of mesenchyme cells which in the preceding
stage was situated between the anterior end of the forebrain,
the dorsal wall of the alimentary canal, and the ventral surface
of the hypophysis. The anterior surface of the hypophysis,
which in the preceding stage was the dorsal surface and which
was then in contact with the outer layer of ectoblast, is now
it: contact with the adhesive organ and button, which, develop-
ing from the crescent of the preceding stage, have grown up
and separated the hypophysis from the ectoblast and forced
it against the anterior wall of the forebrain. The cells com-
posing the hypophysis are more or less columnar in form,
arranged so that their longitudinal axes are approximately
parallel with the longitudinal axis of the hypophysis, especially
at its dorsal end, as if the entire organ had been forcibly
elongated.

Mechanically, the change in the position and form of the
hypophysis between stages I and 2, may be referred to the
rapid enlargement of the cavity of the forebrain and to the
development of the adhesive organ. The enlargement of the
cavity of the forebrain causes the ectoblast in front of the
neuropore, which in the preceding stage was nearly parallel
with the dorsal wall of the alimentary canal to assume a posi-
tion nearly at right angles to it. The upgrowth of the adhe-
sive organ at the same time separates the hypophysis, ante-
riorly and laterally, from the ectoblast, and as already stated
forces it against the anterior wall of the forebrain.

Sections of several embryos both older and younger than
those of the stage just described were studied, but, contrary

500 REIGHARD—MAST. [Vor. XIX.

to the observation of von Kupffer (1893) in Acipenser, no
connection was found between the hypophysis and the ento-
blast, the cells of which may readily be distinguished from
those of ectoblastic origin found in the hypophysis by the large
round yolk granules they contain in contrast with the fine
granules characteristic of ectoblast cells. Fig. 2, which is
from a photograph, shows how distinct these two sorts of
cells are and how sharply the ventral end of the hypophysis is
separated from the entoblast.

Fig. la represents a median longitudinal section of an em-
bryo somewhat younger than that represented in Fig. 6 of
the preceding article, from which Fig. 2 is taken. The section
is slightly oblique. It shows the hypophysis more broadly
connected with the neuropore at its dorsal end than in Fig. 2,
and lying against the posterior face of the button. Otherwise
the condition of the hypophysis is not greatly different from
that shown in Fig. 2.

In the fourth stage of the preceding article, the hypophysis
(Fig. 3, hy.) has lost its connection with the ectoblast entirely
and lies in a horizontal position in the somewhat enlarged
space between the forebrain and the adhesive organ close to
the dorsal wall of the alimentary canal with its posterior end
projecting into the angle between the forebrain and the dorsal
wall of the alimentary canal. The hypophysis considered as
a solid has become somewhat tongue-shaped, and is now com-
posed of a mass of more or less cubical cells. No definite
arrangement of these cells could be determined. It contains
three small inter-cellular cavities, none of which were found
in younger stages. These cavities, some little distance apart,
are situated on a median longitudinal line a little nearer the
posterior than the anterior end of the mass of cells.

A stage between Figs. 2 and 3 is represented in: Fig. 2a.
The hypophysis is here more recently separated from the
neuropore than in the stage of Fig. 3. The embryo from
which this section was taken is externally scarcely distinguish-
able from that shown in Fig. 6 of the preceding article, except
by the single character that its tail is free from the yolk for
a distance equal to thirty degrees of the yolk’s circumference.

No. 2.] THE HYPOPHYSIS OF AMIA. 501

Sections of embryos corresponding in age to the fifth or
hatching stage in the preceding article (Fig. 8), show the
hypophysis (Fig. 4, hy.)? to have changed considerably in
position. It now lies between the ventral wall of the infun-
dibulum and the dorsal wall of the alimentary canal with its
posterior end extending to a point some little distance ahead
of the anterior end of the notochord (Fig. 4, n.), which
reaches the postero-ventral region of the infundibulum. At
this point the infundibulum presents a slight evagination (Fig.
4, sv.), the fundament of the saccus vasculosus. The cavities
first observed in the preceding stage are somewhat larger in
this stage, and the cells, more columnar in form, are arranged
apparently in a single layer around them, forming small vesi-
cles (Fig. 4, c.). The ends of the cells next the cavities are
clear, while their opposite ends contain numerous small gran-
ules among which the nuclei are found.

By comparing the position of the hypophysis in Figs. 3 and
4, it seems to have migrated backward between the dorsal
wall of the alimentary canal and infundibulum independently
of surrounding parts. Mechanically, this change in position
may be explained by supposing that the entire forebrain moves
forward in its courses of development, its ventral wall thus
passing over the hypophysis, and that later its infundibular
region moves backward, due to the formation of the cerebral
flexure, carrying the hypophysis with it. The first supposi-
tion is supported by the fact that the large space between the
anterior end of the forebrain and the ectoblast, seen in Fig. 3,
disappears; the second by the fact that the saddle cleft is much
narrower in Fig. 4 than in Fig. 3.

The hypophysis in embryos about 22 mm. long is found to
be located in the same relative position as in the preceding
stage. It has, however, increased rapidly in size and has be-
come broader and flatter than it was in the earlier stages.
The vesicles (Fig. 5, c.) have increased in number and be-

*The relative difference in size between Figs. 2, 3 and 4 is not due to a
difference in magnification, as might be supposed, but to a difference in
the actual size of the embryos, all being magnified 190 diameters.

502 REIGHARD—MAST. [VoL. XIX.

come elongated to form canals, all of which end blindly at both
ends, as far as could be determined. One exceptionally large
vesicle (Fig. 6, c.) was found situated but a short distance
from the anterior end of the hypophysis in the median plane,
near its ventral surface. This vesicle is approximately cylin-
drical, its length being about ten times as great as its diameter,
which was found to be about five times as great as the diameter
of any of the other vesicles. It is formed by a layer of
columnar cells whose inner ends are hyaline while their outer
ends are granular. No opening could be found leading either
into or from this cavity.

At this stage the hypophysis was found to be well supplied
with blood by vessels (Figs. 5 and 6, b. v.) which enter both
along the median dorsal and the median ventral surfaces from
the posterior end.

On either side of the median line on the dorsal surface
near the posterior end, there are depressions into which project
anteriorly directed ingrowths (Fig. 5, hy.) from the ventral
wall of the infundibulum. These ingrowths distinguish the
nervous portion of the hypophysis, which is designated ramus
hyoideus by Goronowitsch (1883), in Acipenser. They vary
in number in different individuals, there being sometimes two
on either side of the median line and sometimes one on one
side and two on the other. They are composed of neuroglia
(Haller) similar to that found in the walls of the brain tube
at this stage. In the middle of each protuberance there is a
rod-shaped core of nuclei which is surrounded by a layer of
fibrous neuroglia tissue which is separated from the hypophy-
sis by a limiting membrane.

We thus have here indicated a division of the hypophysis
into two portions homologous with the two portions decribed
by Haller (1897) and others in other vertebrates.

SUMMARY OF OBSERVATIONS.

1. The hypophysis of Amia originates at a much earlier
stage than described by Dean (1896) as a solid mass of
cells from the inner layer of the ectoblast between the funda-

No. 2.] THE HAVYPOPHYSES OF AMIA. 503

ment of the adhesive organ and the neuropore. Its tissue is
continuous with that of the neuropore and remote from the
stomodzeum.

2. It loses its connection with the ectoblast and the neuro-
pore tissue and comes to lie between the infundibulum and the
dorsal wall of the alimentary canal.

3. In changing its position it never unites with the ento-
» blast.

4. Its cells contain smaller yolk granules than those found
in entoblast cells and may consequently be readily distin-
guished from cells of entoblastic origin. This is true of the
earliest stages. .

5. In 22 mm. larve it shows a division into a number of
elongated vesicles with well marked cavities.

6. By the penetration into it of nervous tissue (neuroglia,
Haller, 1896) from the infundibulum, it becomes divided into
an anterior and a posterior portion.

7. It is richly supplied with blood-vessels.

DISCUSSION OF RESULTS.

From the foregoing account it appears that the hypophysis
of Amia shows in its development a striking likeness in some
features to the hypophysis of Acipenser as described by v.
Kupffer (1893).

In both cases the hypophysis does not originate from the -
ectoblast of the stomodzeum or near it, but from the ectoblast
at the anterior end of the neural tube in connection with the
anterior neuropore (mediane Riechplatte and lobus olfactorius
impar of v. Kupffer). In both cases there is an adhesive
organ intervening between the fundament of the hypophysis
and the stomodzum. In both cases the hypophysis detaches
itself from the ectoblast and neuropore and takes up a posi-
tion posterior and dorsal to the stomodzum. In both cases its
further history is not essentially different from that of other
vertebrates (Haller, 1896).

Acipenser differs from Amia in that its hypophysis is, ac-
cording to v. Kupffer, tubular in an early stage. This hypophy-

504 REIGHARD—MAST. [Vor xe

sis differs further from that of Amia in being continuous
at its ventral end (in early stages) with the entoblast of the
dorsal wall of the archenteron. The lumen of the tube opens
at one end into the archenteron, while at the other end it is
closed by the outer layer of ectoblast. In Amia we have not
found the hypophysis at any time tubular, nor have we found
any lumen until some time after the separation of the organ
from the ectoblast. We have not at any time found a connec-
tion of the hypophysis with the entoblast.

The hypophysis of Amia is in close contact with the ento-
blastic button, which in an earlier stage is the middle of that
part of the archenteric entoblast designated in the preceding
article as the crescent (Fig. 1). The plane of demarcation
between the ectoblast of the hypophysis and the entoblast of
the crescent or button is not always easy to find. Its visibility
depends on the plane of section. In suitable sections we have
always found it as shown in Fig. 1, and we believe that it
always exists. In respect to these two points, the existence
in it from the beginning of a lumen and the continuity of its
walls with the entoblast, the hypophysis of Amia may be in a
less primitive condition than that of Acipenser.

It is not our purpose to discuss at length the theory ad-
vanced by v. Kupffer, on the basis of his work on Acipenser
and Petromyzon, to the effect that the hypophysis is a palzos-
tome. The development of the organ as we have described
it in Amia certainly adds force to the array of facts adduced
by v. Kupffer in support of his theory.

In this connection it should be noted that we know but three
vertebrates in which the hypophysis originates in connection
with or near the neuropore, Petromyzon, Acipenser and Amia.
In Acipenser and Amia the adhesive organ intervenes between
the hypophysis and the stomodeum. In Ammoccetes the
upper lip occupies the same position as the adhesive organ of
the Ganoids. This suggests the possible homology of the
Ammoceetes upper lip with this adhesive organ.

Von Kupffer believes the position of the hypophysis as
found in these forms to be primitive, the hypophysis to be a

No. 2.] THE HYPOPHYSIS OF AMIA. 505

palazeostome and its connection with the stomodeum in other
vertebrates to be a secondary condition correlated with the
increased size of the forebrain and the loss of the adhesive
organ. That such a condition as the connection of hypophysis
and stomodzeum could come about through the secondary dis-
placement of the hypophysis he considers “schwer zu ver-
stehen.”” Whether the position of the hypophysis in these
three forms is primary or secondary, depends, it seems to us,
on whether the adhesive organ is a primitive organ formerly
possessed by all vertebrates, or an organ which has made its
appearance in only a few groups and has in these groups
caused the displacement of the hypophysis from a position in
the stomodzum to a more dorsal position. This question can
scarcely be answered until we know more of the adhesive
organ itself and its homologues. Until our knowledge on this
subject is increased one of these alternatives seems to us nearly
as probable as the other; although, as v. Kupffer points out,
the early appearance and large size of the Acipenser hypophy-
sis is probable evidence of its primitive character.

Since the foregoing was written there has appeared a paper
by Prather (1900) on the development of the hypophysis in
Amia. The earliest embryo in which Prather has found the
hypophysis is one a few hours before hatching, corresponding,
therefore, very closely to Fig. 8 of the preceding article, In
this stage he finds it in process of being differentiated out
of the entoblast of the dorsal wall, of the foregut, ventral to
the infundibulum, that is essentially in its adult position.
His account thus differs from ours chiefly in two particulars:
(1) He has not seen the early stages in the development of
the hyphophysis as described by us. (2) He derives the
hypophysis from the entoblast; whereas, according to our
account, it is ectoblastic.

Through the kindness of Dr. Eycleshymer one of us has been
able to examine the sections on which Prather’s studies were
made. They show what Prather has described. Having had
an experience of many years in the preservation of Amia
material and in the preparation of sections from it, we be-

506 REIGHARD—MAST. [VoL. XIX.

lieve that we are justified in saying that the differences be-
tween Prather’s results and ours are due to the insufficiency of
the methods used in the preparation of his material. His Fig.
1 shows that in the material used by him, the egg membranes
had not been removed from the eggs before preserving them.
The figure shows also that in this case the membranes had
shrunken down close against the embryo. The result of
this is that the tissues of the embryo are pressed together and
the limits between adjacent tissues are frequently obliterated.
The hypophysis is not then visible in its early stages, and in
the stages some time before hatching it is so pressed into the
entoblast of the dorsal foregut wall as to be scarcely distin-
guishable. Such a condition is shown in Prather’s Fig. 3.
At the time of hatching or upon removal of the egg mem-
branes the pressure from them is, of course, removed, and the
hypophysis, being no longer pressed into the dorsal foregut
wall, becomes visible and appears to be differentiated in situ
out of the entoblast.

We have tried every feasible method of preserving these
eggs without shrinkage of the membranes and have not found
any method hitherto in use that accomplishes this. One of
us has, however, devised a fluid, consisting of a five per cent
formalin solution (i. e., containing two per cent of formalde-
hyde) to which is added two or three per cent of potassium
bichromate and ten per cent of glacial acetic acid. This fluid
used for eight hours or longer causes not more than a very
insignificant shrinkage of the membranes or none at all. It
is not stable and should be used fresh. Eggs are transferred
from it to four per cent formalin which is changed until no
longer discolored by the bichromate, and are then preserved
permanently in the formalin. The histological results are
similar to those obtained from Flemming’s or Hermann’s fluids
and are excellent, as may be judged from the figures of cell
divisions visible in Fig. 2. In spite of the results obtairied from
this fluid we have made it a rule, before preserving the eggs, to
remove the membranes from them in the earliest stages prac-
ticable. This may be done in the stage represented by Fig.

No. 2.] THE HYPOPHYSIS OF AMIA. 507

6 of the preceding article, and (by using very great care) in
somewhat earlier stages.

A comparison of our Fig. 4 with Prather’s Fig. 3 of approx-
imately the same stage will show the differences between eggs
preserved with and without removal of the membranes.

From the foregoing we believe that Prather is in error in
regarding the hypophysis as of entoblastic origin. Prather
gives a brief summary of opinions that have been hitherto
held as to the origin of the hypophysis. From this it appears
that the view that the hypophysis is of entoblastic origin
exclusively has not been maintained since 1882. Nearly all
recent writers have maintained its ectoblastic origin (though
a few have regarded it as of mixed origin). We believe that
we have shown that Amia, also, must now be placed among
those forms concerning the ectoblastic origin of whose hy-
pophysis there is no question.

Prather believes that the structure which v. Kupffer (1893)
has described and figured in early stages of Acipenser (Figs.
13, 14) as the hypophysis is in reality the adhesive organ of
that form. This belief he bases on the two facts; that the
hypophysis is described by v. Kupffer as laden with food yolk,
and that it has the appearance of being a dorsal diverticulum
of the entoblast. Both of these characteristics distinguish
the adhesive organ of Amia, and may be expected to be
characteristic of that of Acipenser also. An investigation in
progress in this laboratory on the adhesive organ of Lepi-
dosteus has given figures of median sections strikingly like
Fig. 13 of v. Kupffer (1893). In these sections there is in
front of the brain an entoblastic tube with its lumen’ and
walls continuous below with those of the foregut. The tube
is flattened and may be traced in series of longitudinal sec-
tions from one side of the brain to the other. It is therefore
as wide as the brain. Its position and relation to surrounding
structures are the same as that figured for the hypophysis of
Acipenser by v. Kupffer, but its subsequent history shows it
to be the adhesive organ. These observations on Lepidos-
teus certainly lend weight to Prather’s suspicion. On the

o8 REIGHARD—MAST. [VoL. XIX.

in

other hand, the very circumstantial account which v. Kupffer
gives of the transformation of the tubular fundament of the
hypophysis of the embryo of Acipenser into what is undoubt-
edly the hypophysis of the larva, and his clear though very
diagrammatic figures make it necessary to wait for a re-in-
vestigation of Acipenser before pronouncing judgment.

With our present knowledge it seems to us most likely
that what v. Kupffer describes as the fundament of the
hypophysis in Acipenser is really such. This view is strength-
ened by the likeness of its development to that described for
Amia. The dorsal diverticulum of the archenteron shown
in v. Kupffer’s Fig. 13, between en. and vd., is the probable
homologue of the Amia adhesive organ. V. Kupffer speaks
of this structure as a “quer gelagerten Wulste des Entoderms,
: der jederseits von der Mittellinie sich taschenartig
gestaltet.”’ Its form is thus not unlike that of the Amia adhe-
sive organ in an early stage, and its position is the same. V.
Kupffer himself suggests its possible homology with the ante-
rior head cavities of Acanthias, structures which in the pre-
ceding paper are considered to be the homologues of the adhe-
sive organ of Amia.

If it be true that this diverticulum of the foregut of Acipenser
seen in v. Kupffer’s Fig. 13 corresponds to the adhesive organ
of Amia we should expect that the structure marked _ hf.
(Haftscheibe) in the same figure is in reality a part of this
entoblastic diverticulum and not, as stated by v. Kupffer, a
thickening of the ectoblast. With this slight alteration v.
Kupffer’s account of Acipenser would be in substantial agree-
ment with that given for Amia in this and the preceding
papers.

LITERATURE CITED.
DEAN, Basurorp, 1896. On the Larval Development of Amia calva. Zool.
Jahrb., IX, 639-672.
Goronowirscu, N., 1883. Das Gehirn und die Cranialnerven von Acipenser
ruthenus. Morph. Jahrb., XIII, 427-574.
Hatter, B., 1896. Untersuchungen itber die Hypophyse und die Infundi-
bularorgane. Morph. Jahrb., XXV, 1, 31-114.

No. 2.] THE HYPOPAY SIS OF AV: 509

KupprFer, C. von, 1893. Studien zur vergleichenden Entwickelungsgeschichte
des Kopfes der Kranioten. I. Die Entwickelung des Kopfes von
Acipenser ruthenus an Medianschnitten untersucht.

PraTHER, J. M., 1900. The Early Stages in the Development of the
Hypophysis of Amia calva. Biological Bulletin, I (2), 51-80.

EXPLANATION OF PEATE.

All figures are photographs of sections and are magnified about one
hundred fifty diameters. They have been slightly retouched with the
pencil, for the purpose of adding to the distinctness of certain teatures.
Nothing has been added with the pencil to that which was visible in the
original photographs.

REFERENCE LETTERS FOR ALL FIGURES.

ad—adhesive organ (crescent).
al—alimentary canal.

b—button.

bv—blood-vessel.

c—cavity in hypophysis.

h—heart.

hy—hypophysis.

hy’—posterior lobe of hypophysis.
in—infundibular region of brain.
m—position of future mouth opening.
me, me’—mesenchyme.
n—notochord.

np—neuropore.

st—stomodeum.

s. v.—saccus vasculosus.

Fic. 1—A median longitudinal section (sagittal) of an Amia embryo of
the stage of the one shown in Fig. 1 of the preceding article.

Fic. 1a—An approximately longitudinal section of an embryo somewhat
younger than the one represented in Fig. 6 of the preceding article.

Fic. 2a—A median longitudinal section of an embryo a little older than
of the preceding article.

Fic 2a.—A median longitudinal section of an embryo a little older than
the one represented in Fig. 6 of the preceding article.

Fic. 3—A median longitudinal section of an embryo still a little older
than that shown in Fig. 6 of the preceding article, and older than the last.

Fic. 4.—A median longitudinal section of the hypophysis and surround-
ing structures of an embryo of the hatching stage (Fig. 8 of the preceding
article).

Fic. 5.—A longitudinal section of the hypophysis and surrounding tissue
of a larva of Amia, 22 mm. long, taken a little to one side of the median
plane.

Frc. 6—A median longitudinal section of the hypophysis and surround-
ing tissue of a larva of Amia, 22 mm. long.

POPHYSIS OF
" REIGHARD AND MAST

FIG. 1 A.

FIG. 5
JOURNAL OF MORPHOLOGY—VOL. XIX, NO. 2 ag

THE LATERAL LINE SYSTEM IN EXTINCT
AMPHIBIA.

Roy L. Moonie.

The University of Chicago.

The study of the system of canals and sense organs in the
lower vertebrates, known as the lateral line system, has inter-
ested many anatomists. The existence of the lateral line
system was first observed, of course, in the fishes where it
is clearly marked, more especially on the body of the fish.
According to Collinge (1), the lateral line organs were first
observed on a species of skate by Stenonis in 1664, and in
1669 on some of the sharks. The term canal was first applied
to this set of structures under the preconceived idea that there
was an actual canal under the skin, as indeed there seems to
be in some cases, and M’Donnell (2) tells us of his attempts
to inject the system of canals with a syringe. Various means
were devised for studying the anatomy of this peculiar set
of structures and many theories were propounded as to its
possible functions. The general opinion was that the lateral
line structures were secreting organs and the grooves on the
crania of fishes and on the skulls of the ancient Amphibia are
almost universally spoken of as slime canals or mucous canals
or grooves.

Through the recent embryological and anatomical studies of
Allis, Pollard, Platt, Collinge, Cole, Parker, Takahashi, Har-
rison, and others, the full development and functions of the
lateral line system have been made out in a few forms.

It is now generally admitted, especially since the excellent
experiments of Parker (3) on the function of these organs in
fishes, that the lateral line system is a set of-sense organs inter-
mediate in function between the organs of touch and those
of hearing, but more delicate than either in some respects.

(511)

512 MOODIE. [VoLt. XIX.

Parker ascertained that the lateral line organs in some of the
fishes seemed to respond to slow wave vibrations. It is thus
through the action of wave vibrations on the external lateral
line organs that the animal is notified of a disturbance in the
water near it, the wave vibrations of which were too slow to
affect the organs of touch or hearing.

It is not our purpose to discuss here the functions of these
organs, but to describe the manner of their occurrence in the
ancient Amphibia, on the crania of which the canals are often
clearly marked. Unfortunately there are but comparatively
few skulls in existence and they are scattered far and wide
in the museums of the world. The remains of the early
Amphibia are represented in great part by fragments.
Occasionally, however, a good skull is discovered and almost
always the lateral line canals are well shown on such skulls.
But there is another source of grievance. When such good
skulls are described, the describer of the specimen either pays
but scanty attention to the subject of the lateral line system,
or omits a discussion of it altogether or describes the canals
inadequately. We are indebted to the paleontologists of the
world for the knowledge we have of the lateral line canals
of the ancient Amphibia and more especially to von Meyer and
Fraas.

The lateral line system, as preserved in the extinct Amphibia,
is of a very peculiar character and is unlike anything with
which I am acquainted among the fishes, although some degree
of correlation is possible. The entire set of structures on the
skull of the Stegocephala is usually spoken of as the lyre or
lyra, the former being the more correct term. The system
of organs is represented by canals of various forms and with
varying directions. They are usually in the form of gutters
with more or less vertical sides, although sometimes, espe-
cially among the Microsauria, the canal is represented by a
row of elongate pits. The bottoms of the well-formed canals
may be smooth or roughened by pits such as commonly occur
in the crania of the Stegocephala. The smoothness of the
bottoms of the canals is, I think, an indication either of age

No. 2.] LATERAL LINE IN EXTINCT AMPHIBIA. 513

or of specialization, for I have observed that in the more
generalized forms the line canals are roughened by the vascular
pits, but in the highly specialized labyrinthodonts the bottoms
of the canals are usually rather smooth, and this smoothness
increases as the animal grows older. The canals of the
lateral line organs are always open and never have the canals
roofed over as is the case, according to Dean (4), in some of
the Arthrognathid fish-like vertebrates.

Pollard (5), Baur (6), and Allis (7) have attempted some
correlation of the cranial elements of the fishes and Stego-
cephala on the basis of the lateral line system. Baur’s work
had to deal with the stegocephalan side of the question and
the others treated the question from the fish point of view.
Allis’ paper on the homologies of the squamosal and other ele-
ments is especially instructive. Pollard, according to Baur,
did not fully understand the arrangement of the lateral line
organs in the Polypterus which he was studying, having
failed to comprehend the significance of the occipital cross-
commissure. Baur did not complete the homologies of the
crania of the fishes and stegocephalans, but carried the cor-
relations as far as was then possible. In my studies on the
Carboniferous Amphibia, I have been led to investigate the
conditions of the lateral line system in the extinct forms to
see if some definite idea might be formed as to the homology
of the squamosal and supratemporal elements in the skull
of the Stegocephala. The investigation was undertaken in
the hopes of ascertaining just what the element which lies
laterad to the parietal in most forms of the Stegocephala is,
whether it is the squamosal, prosquamosal or supratemporal,
all of which names have been applied to it by various authors.

An attempt has been made to correlate the lateral line canals
in the Stegocephala with those of the fishes and recent
Amphibia. In the accompanying diagram (Fig. 1), there
are represented all of the canals which occur on the crania of
the Stegocephala. They do not all occur in any one species
nor indeed in any one group, but are all found in more or less
well-developed form in some of the extinct Amphibia. The

514 MOODIE. [Morse

nomenclature here proposed, it 1s hoped, does not depart widely
from that given by Allis for Amia (8). The supraorbital
(Fig. 1 “d”) and infraorbital (Fig. 1 “c’) canals are readily
correlated with the canals of the same name in the fishes. The
anterior commissure (Fig. I “a’) is also homologous with
that of fishes, as is also the canal which is here called the

Fic. 1—A diagram of the lateral line canals in the Stegocephala.

a, anterior commissure; b, antorbital commissure; c, infraorbital canal;
d, supraorbital canal; e, temporal canal; f, jugal canal; g, occipital cross-
commissure,

E, epiotic; F, frontal; J, jugal; L, lachrymal; Mx, maxilla; P, parie-
tal; Pf, postfrontal; Po, postorbital; Pr, prefrontal; Prs, supratemporal ;
Px, premaxilla; Qj, quadrato-jugal; So, supraoccipital.

“antorbital commissure” (Fig. 1 “b’.). The others: are- not
so readily homologized. The upper canal in the posterior
part of the cranium is here designated the “temporal canal”
(Fig. 1 “e’). It is, however, clearly a part of the infraorbital
canal of the fishes. Its relations in the Stegocephala are
such that a new name is deemed necessary, for otherwise the
canal would have to be referred to by the circumlocution:
“the upper posterior portion of the infraorbital canal.’ For the

No. 2.] LATERAL LINE IN EXTINCT AMPHIBIA. 515

lower posterior portion of the infraorbital canal I propose the
term “jugal canal” (Fig. 1 “f’’), since it lies in great part on
that element of the skull. The jugal canal is, I believe, a new
formation in the Stegocephala. I am unable to homologize
it with anything which I can find occurring in fishes. It may
be composed of the infraorbital and a portion of the operculo-
mandibular canal, but of this I am not sure. The most poste-
rior canal of the stegocephalan skull is homologous with the

Fic. 2.—Outline of the lateral line canals on the skull of Amia calva.
Lettering as in Fig. r. After Allis.

Fic. 3.—Outline of the lateral line canals on the skull of Polypterus.
After Baur and Traquair.

supratemporal cross-commissure of Amia as defined by Allis,
and it is here designated the “occipital cross-commissure”’
(Fig. 1 “g’’). Allis (1899) was doubtful as to whether this
canal could be homologous with the same placed canal in Amia
and Polypterus, and was inclined to correlate it with a canal
which occurs in other fishes and which would distinctly change
the correlations of the cranial elements. There can be no
doubt, however, that the ‘occipital cross-commissure” is the

516 MOODIE. [Vot. XIX.

same as the supratemporal cross-commissure of Amia. It
will be noticed that the main canal in the Stegocephala is
the infraorbital canal as it is in Amia and Polyterus (Figs.
2, 3). In the Stegocephala likewise, the main canal always,
or almost always, cuts the epiotic as it does that element in
the fishes which Baur would correlate with the epiotic.

There are five suborders of the extinct Amphibia (9) in
nearly all of which there have been detected evidences of the
lateral line system. ‘The extinct Amphibia of the pre-Juras-
sic are known as the Stegocephala and the five suborders of
this group may be designated: the Branchiosauria, the Micro-
sauria, the Aistopoda, the Temnospondylia and the Stereos-
pondylia. In all of these suborders, with the exception of the
Aistopoda, the lateral line system has been observed. The
canals are more clearly preserved on the skulls of the Stereo-
spondylia than in any of the other groups, the reasons for
which we will consider later.

The Branchiosauria are known by numerous individuals of
several species found abundantly in Europe in the Upper Car-
boniferous and Permian, and by a single species founded on a
single well-preserved specimen from the Carboniferous of Illi-
nois. [he Branchiosauria are the best preserved of all of the
extinct Amphibia and not only is the complete skeletal anatomy
known, but something of the soft parts, color markings, cov-
ering and habits. Credner (10) has been able to write an
interesting paleontological embryology based on the Branch-
iosauria preserved in the Permian rocks of Saxony and adja-
cent regions. The European students of the Branchiosauria
have not, unfortunately, paid any special attention to the study
of the lateral line system as it is preserved in the Branchio-
sauria. Thevenin (11) barely mentions the occurrence, of the
lateral line on the specimens he studied from the Upper Car-
boniferous rocks of France. It is to be hoped that more may
be added to our knowledge of this portion of the anatomy of
the Branchiosauria.

The form from Illinois, described elsewhere (9) as Micrer-
peton caudatum gen. et. sp. nov. (Fig. 4), is a very small ani-

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No. 2.] LATERAL LINE IN EXTINCT AMPHIBIA. 517

mal, apparently adult. It measures 49 millimeters in length
or a little less than two inches. It is preserved, almost per-
fectly, in one of the nodules from Mazon Creek, Grundy
County, Illinois; the collector in splitting the nodule lost the
chips containing the hands and feet. From this specimen not
a few new characters have been added to those already known
for the Branchiosauria such as certain color markings on the
body, the character of the dermal covering, and most important
of all, the presence of a distinct type of lateral line preserved
clearly and distinctly on the impression of the fleshy tail. This

Fic. 4—Impression of Micrerpeton caudatum Moodie, from the Car-
boniferous of Illinois. Twice natural size.

has been fully described elsewhere, but it is deemed of such
importance that a redescription is here given.

“The most interesting and important single structure dis-
covered on the specimen is the impression of the lateral line
system which is clearly evident as two dark lines on the impres-
sion of the fleshy part of the tail. The sense organs are
represented by two longitudinal rows of pigmented scales.
one beginning at the tip of the tail, the other taking its origin
from the median line somewhat further forward (Fig. 5).
I am indebted to Dr. Takahashi for calling my attention to the
similarity of this arrangement to that found in ti.: modern

518 MOODIE. [Vor. XIX.

Necturus (Fig. 6). The arrangement and disposition of the
lines containing the sense organs is practically the same in the
two forms. The median lateral line takes its origin from the
extreme tip of the tail or rather it ends there, and is continued
to the base where the impression is broken. The dorsal lateral
line has its origin rather abruptly from the median line at a
distance of six millimeters from the tip of the tail. The
sense organs were undoubtedly located beneath specialized
pigmented scales on the surface of the animal’s body as in

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Fic. 5.—Detail of lateral line on impresion of the tail of Micrerpeton
caudatum. d, dorsal lateral line; m, median lateral line; xxx, impressions
of cartilaginous vertebre. X 4.

Fic. 6—Outline of the larva of Necturus maculosus Raf., showing
arrangement of lateral line organs. d, dorsal lateral line; m, median
lateral line; v, ventral lateral line. After Platt. Enlarged.

many of the modern fishes, e. g., the Holocephali, and to this
pigment is due the preservation of the lines in a visible form.

“The fact that the arrangement of the lines of the sense
organs of Micrerpeton corresponds so exactly to the condition
found in Necturus is of considerable interest. Necturus alone
among the modern tailed Amphibia has the arrangement of
the lateral lines above described for Micrerpeton. All other
forms of the Caudata as also the larval forms of the Salientia
have an arrangement of the lateral line system which is per-

No. 2.] LATERAL LINE IN EXTINCT AMPHIBIA. 519

fectly distinct from that found in Necturus, although the same
general plan is observable in all. The Necturus is, I believe,
a more generalized type of amphibian so far as the lateral
line is concerned than any of the other modern forms. This
preservation of the lateral line system so perfect is due, with-
out doubt, to the constant water habitat of the animal. Kings-
bury (12) has expressed it as his opinion that Necturus is a
primitive form and bases his conclusions on other grounds
than that of the lateral line system. In very few of the modern
Amphibia is the median line present as far back as the tip of
the tail and in none, so far as I can learn, are the median and
dorsal lines both present on the tail except in the Necturus.
Other forms have lost the line from the tail, and this but
gives expression to the general law that structures present over
the entire body are lost first in the posterior region. This
finds another expression in the loss of stripes by the zebras
where in the quagga the hind part of the animal is destitute
of stripes. In Ambystoma, for instance, the median lateral
line is not present on the tail at all and the dorsal line is but
imperfectly developed (13). The close similarity of the
arrangement of the sense organs in the two forms, Necturus
and Micrerpeton, may be of genetic significance with regard
to the former group.

“The interval of time which has elapsed from the age in
which Micrerpeton lived to the present is reckoned by many
millions of years. But since the lateral line organs are of
fundamental significance and since they are subject to compar-
atively little variation, this system of sense organs in the
Amphibia may have persisted through the ages unchanged as
we know it has done in some of the fishes (14). The ances-
tors of the modern Caudata and Salientia must have originated
somewhere in the Carboniferous or earlier ages. Among all
of the extinct Amphibia there are none which could have
given rise to the modern forms save the Branchiosauria. The
Microsauria are too highly specialized when we first know
them in the Carboniferous, and they are already tending
toward the reptilian type, to some groups of which they prob-

520 MOODIE. [Vor. XIX.

ably gave rise. The other groups of extinct Amphibia are,
of course, out of the question so far as being ancestral to the
modern Amphibia is concerned. The Aistopoda, when we
first know them, are highly specialized, snake-like Amphibia
and could not have given rise to animals with legs since it
is well-known that they are descended from forms with well-
developed limbs as is evidenced by the vestigial pectoral gir-
dle in Ptyonius. The Temnospondylia and Stereospondylia,
which are closely related, were also highly specialized along
their own line, and like the Pterodactyles went out of exist-
ence completely and, so far as we know, left no descendants.
There is certainly nothing in the structure of the Branchio-
sauria to prevent their being ancestral forms to the modern
Amphibia. There is much in favor of it. The idea is not a
new one but has been suggested by Baur and others. We have
here, however, for the first time, something definite on which
to base our conclusions.” This matter is discussed more fully
elsewhere. The cranium of the Branchiosauria, like the
modern Amphibia, is never grooved by the lateral line canals,
but the system was undoubtedly present on the skull in the
skin, much as it is in the modern forms.

In the Microsauria, although there are numerous forms
known, there have been but few observations made on the
lateral line system. There are evidences of the canals on a
skull and mandibles of Diplocaulus, Andrews (15) has
observed rows of pits on the skull of Ceraterpeton galvani
Huxley from the Carboniferous rocks of Staffordshire, Eng-
land, and the writer has recently detected them on an excel-
lent skull of Tuditanus tabulatus Cope from the Linton, Ohio,
beds and traces of the supraorbital canal have been observed
on the skull of Stegops divaricata Cope from the same local-
ity.

In the Ceraterpeton specimen (Fig. 7) there are evidences
of the lateral lines on the posterior and upper portions of the
skull only. They consist in the occipital cross-commissure,
the temporal canal and a portion of the supraorbital canal.

No. 2.] LATERAL LINE IN EXTINCT AMPHIBIA. 521

The infraorbital, the anterior commissure, and the jugal canals
were not detected. The presence of a well-developed occipital
cross-commissure in the skull of Ceraterpeton is of interest
because this structure is rarely present in the more highly
specialized labyrinthodonts. This is a generalized character
as may be seen by referring to the figures of the Actinoptery-
gian, Amia, and the Crossopterygian, Polypterus, in both of
which the occipital cross-commissure is well-developed. The

Fic. 7.—Outline of the skull of Ceraterpeton galvani Huxley from the
Carboniferous of England, showing the distribution of the lateral line
canals. After Andrews. Natural size.

Fic. 8.—Outline of the skull of Tuditanus tabulatus Cope, showing the
arrangement of the lateral line canals in their relations to the cranial
elements. One and one-third natural size.

Fic. 9 —The mandible of Diplocaulus magnicornis Cope, showing oper-
culo-mandibular canal from the side. One-half natural size.

temporal canal, which is a portion of the infraorbital, begins
its course on the epiotic and crosses most of the squamosal
when it is lost. The supraorbital canal occurs on the frontal
and postfrontal and has the usual relations for that canal.

The lateral line canals are but weakly developed in the -
cranial region of Diplocaulus. On a nearly perfect skull and
mandibles of the species D. magnicornis Cope in the collection
of the University of Chicago, there are traces of only three of

522 MOODIE. [VoL. XIX.

the canals. On the mandibles, the operculo-mandibular canal
is well-marked (Figs. 9, 9a). The canal, apparently, has
a course completely around the mandibles, although the ante-
rior portion of each mandibular ramus has been broken and
lost. However, at the point where the ramus is broken the
canal is still strongly marked. The canal has its course, for
the most part, near the middle of the rami, but as it approaches
the posterior angle of the mandible it suddenly changes its
course and drops down to the lower edge only to rise again
and to come out strongly marked near the median plane on the
posterior angle of the mandible. On the dorsal surface of the
skull (Fig. 10) there are faint traces of the canals and on the

Fic. ga.—The mandibles of Diplocaulus magnicornis Cope as seen from
below. The operculo-mandibular canal at the arrow. One-half natural
size.

edges the infraorbital is clearly marked. The arrows on the
skull indicate the positions where the canals were detected.
The long arrow points to a doubtful indication of the supra-
orbital canal. The infraorbital is clearly marked where it is
preserved, but the premaxillary region of the skull is lost so the
entire extent of the canal cannot be determined.

On the skull of Tuditanus tabulatus Cope (in the Zoological
collection of Columbia University, New York City) there are
evidences of a nearly complete system of canals (Fig. 8). The
fore part of the skull anterior to the transverse line has been
lost so that portion is unknown since the species is represented
by a single specimen. The occipital cross-commissure is rep-

No. 2.] LATERAL LINE IN EXTINCT AMPHIBIA. 523

resented on the posterior border of the skull by elongate pits
such as Andrews has described for Ceraterpeton. I fail to
detect any pores in connection therewith such as Andrews
describes for the lines in Ceraterpeton, and indeed I would be
surprised if there were any since there is no evidence that
the lateral line system in the Stegocephala was other than
superficial. The temporal canal forms with the jugal canal
a complete ring in this form much as in Trematosaurus, only
in Tuditanus the temporal canal does not touch the epiotic. I
think there are evidences of a former connection of the tem-

Fic. 10.—Photograph of the skull of Diplocaulus magnicornis Cope.
The arrows indicate the regions where the canals occur. One-third
natural size.

poral canal with the supraorbital, but am not sure of it. It is
so represented tentatively in the diagram (Fig. 8). The tem-
poral canal cuts the supratemporal (prosquamosal), the squa-
mosal and the jugal. The jugal canal lies for the most part
on the supratemporal and quadratojugal. It joins the infraor-
bital on the jugal. A portion only of the infraorbital is pre-
served and the remainder, i. e., its connection with the jugal
canal, is restored. There is a portion of the supraorbital
canal preserved. It seems not to be connected with the tem-
poral canal, although there is a possible indication of this con-

524 MOODIE. [VoLt. XIX.

nection as has been stated above. ‘The supraorbital crosses
the frontal, prefontal and a part of the nasal. The squamosal
element in Tuditanus tabulatus Cope is peculiar in that it is
excluded from the parietal by the extension of the epiotic and
postorbital. This condition is found in several other species
of the Microsauria. It will be noticed that with the changed
condition of the position of the squamosal, the temporal canal
has changed also and this is further proof of the close connec-
tion between the cranial elements and the lateral line canals.

Fic. 11.—The cranium of Eryops megacephalus Cope with the cranial
elements and the associated lateral line canals. Modified after Branson.
One-ninth natural size.

Among the Temnospondylia the lateral line canals are well-
developed on some of the skulls, such as Cricotus, Eryops, and
Archegosaurus. I have had the opportunity of studying only
one of these forms, that of Eryops megacephalus Cope (Fig.
11), from the Permian of Texas, represented by an almost per-
fect skull in the collection of the University of Chicago. This
skull presents very striking characters as to the lateral line
canals. The entire surface of the cranial elements in Eryops
as in other of the Stegocephala is covered with coarse pits.
The fossze are present even in the bottoms of the grooves

No.2] LATERAL LINE IN EXTINCT AMPHIBIA. 525

which represent the lateral line system. This character is
more marked in Eryops than in the Stereospondylia, a matter
of considerable importance as we shall see.

The occipital cross-commissure is well-developed in Eryops.
It is short and ends abruptly within the limits of the epiotics.
Its ends are occupied by large pits. The cross-commissure, as
in Amia, grooves the supraoccipital and epiotic elements.
There is no evidence of an anterior commissure. I think there
is an evidence of a temporal canal on the left side of the skull,
but am not sure. This part.of the skull is imperfect on the
right side. The jugal and infraorbital canals are well-developed
and strongly connected. The jugal canal starts far back on
the supratemporal (prs), and after curving around over the
quadratojugal joins the infraorbital somewhere on the jugal.
There is nothing unusual in the characters of the infraorbital.
The antorbital commissure is well developed in Eryops. It
is longer and better developed in this form than in any other
known to the writer. The supraorbital canal starts anterior
to the nostril and makes a decided bend downwards to meet
the antorbital commissure. It ends abruptly on the postfrontal
bone. The squamosal is apparently not grooved in this form.
The position of this element is a little doubtful as Branson has
stated and the diagram of the cranial elements given is based
on his studies of the skull. The antorbital commissure is
primitively a branch of the supraorbital. It is such in the
fishes and Dr. Takahashi informs me it is the same in Nec-
turus. It would be an interesting matter if we could deter-
mine the points of origin of the lateral line canals in Eryops,
and some day this may be known when we get material rep-
resenting the youthful stages of the form. The peculiarly
specialized condition of the lateral line canals bears witness
to the specialization of the form. This is borne out by its
osteology. Branson has shown that in its vertebral struc-
ture it is approaching the Stereospondylia, the most highly
specialized of all of the Stegocephala.

There are faint traces of the lateral line canals on a poorly
preserved mandible of Eryops in the collection of the Univer-

526 MOODIE. [Vor. XIX.

sity of Chicago. It does not differ greatly from that
described below for the mandible of Anaschisma.

Although Archegosaurus (16) has been known for nearly
sixty-five years, we have had as yet no adequate discussion of
the manner of occurrence of the lateral line canals on the
cranium of this form, where they assuredly occur. Bur-
meister, it is true, gave a figure of the canals as he thought
they occurred on the cranium, but von Meyer states (16) that
his representation is incorrect and seemed to be based in large
part on the cranium of Trematosaurus. Although von Meyer
criticised Burmeister’s representation of the canals, yet he
himself does not give any representation except in patches
here and there on the skulls. Surely among the nearly two
hundred specimens which von Meyer had at his disposal when
he wrote on Archegosaurus there was sufficient information to
have given such a restoration. There are two poorly pre-
served skulls of Archegosaurus decheni Goldfuss in the Field
Museum. I have studied these specimens, which are preserved
in the characteristic nodules much like those from the Mazon
Creek region, but was unable to make out anything definite
in regard to the lateral line canals on account of the poor state
of preservation. The or!ly other well-known form of the
Temnospondylia with which I am acquainted, is that of Gond-
wanosaurus. This is represented by an almost entire cran-
ium, but the cranial elements have almost all disappeared and
have left only the sandstone cast.

The lateral line canals are well developed on the skulls of
the Stereospondylia. Like the majority of the Stegocephala
the cranial elements are strongly pitted and grooved. The
sutures between the elements of the skull are usually clearly
marked by smooth, narrow grooves. The lateral line canals
can always be distinguished from the sutural grooves by the
shape of the bottom, being U-shaped in the former, and V-
shaped in the latter. The lateral line canals also at times have
their bottoms roughened by pits occurring in them, the sutural
grooves always have smooth bottoms. ‘The lateral line canals
are “usually rather shallow and sometimes broad with the

No. 2.] LATERAL LINE IN EXTINCT AMPHIBIA. 527

x

edges of the grooves more or less perpendicular, but in
Metoposaurus the canals are deep and the borders are sharply
incised.

Why the lateral line canals are more deeply incised on the
skulls of the Stereospondylia is not easy to determine. This
suborder is the most highly specialized of all of the Stego-
cephala and it is a part of this specialization that the canals
are deeply incised. The canals become more strongly marked
as the individual grows older, and it is possible that the same
will hold for the suborder. This suborder began, or at least
we find the first evidences of it, in the Carboniferous at the
same time that all of the other groups are represented by
well-developed forms. All of the other groups, however, died
out or became modified into other forms, so far as our pres-
ent knowledge goes, before the Triassic or at least we know
nothing of them after the close of the Permian. The Ste-
reospondylia, however, did not become extinct until the latter
part of the Trias or the early Jurassic. It is thus the long-
est lived of any of the groups of the Stegocephala as such,
and for this reason we may consider that the lateral line canals
are strongly developed. In Eryops, attention has already been
called to the coarse pits occurring in the bottonis of the canals,
and it must be stated that the canals in Eryops are not so
well-developed as in the labyrinthodonts. It is thus evident,
if we take Eryops to be a primitive form, that the primitive
characters of the lateral line canals are the occurrence of deep
coarse pits in the bottoms and their broad character and weak-
ness of development. In other words the lateral line canals
in the Stegocephala are, in their earliest development, rows
of pits which later become developed into well-defined grooves.
Whether the condition described for Eryops will hold for other
of the Temnospondylia remains to be determined. In the
Stereospondylia the canals, as stated, are usually clearly
marked and often have smooth bottoms.

In the collection of the University of Chicago, there are two
perfect skulls of labyrinthodonts, collected some years ago by
Mr. N. H. Brown, of Lander, Wyoming, in the Triassic rocks

528 MOODIE. [Vor. XIX.

some eight miles southwest of Lander. These skulls were
described in 1905, by Dr. Branson (17), as two _ species,
Anaschisma browni for the larger specimen (Figs. 12, 14.), and
A. brachygnatha for the smaller skull. From my own study
of the type specimens, I believe that the latter is but a youth-
ful form of the former species. This is evidenced in several

Fic. 12.—The larger skull of Anaschisma browni Branson, showing
distribution of canals. After Branson. One-fourth natural size.

particulars. The skull designated A. brachygnatha is nar-
rower and shorter than the skull designated by A. brown.
The broadening and lengthening of the skull would, of course,
come with age. The vascular pits on the upper surface of the
smaller skull are weaker and their borders are not so clearly
defined as in the large skull. The position of the orbits is
slightly different in the two skulls, but not enough to be of
specific importance, and the difference is, in all probability, an

No. 2.] LATERAL LINE IN EXTINCT AMPHIBIA. 529

individual variation since it is very slight. But it is the lateral
line canals that the chief points of resemblance lie. The gen-
eral plan of the canals is identical in the two skulls. The only
difference is this: the connection between the temporal and
supraorbital canals is absent in the younger skull while in the
adult it is well developed. The pits in the bottoms of the

Fic. 13.—The skull of Metoposaurus diagnosticus von Meyer, showing
the manner of distribution and occurrence of the canals. After Fraas.
One-fifth natural size.

canals are more clearly marked in the younger than in the
adult skull, and this is an indication of youth. There is
another factor which tends to corroborate the statement as to
the specific identity of the two skulls. They were found to be
slightly overlapping each other in the rocks. This might

530 MOODIE. [Vor. XIX.

not be of importance were there remains of other species of
labyrinthodonts known from these deposits. There are lit-
erally millions of fragments of labyrinthodont skeletons
scattered along the exposures of the Popo Agie beds of

Wyoming for a distance of more than thirty miles, but all’

of the fragments are of the same character and these two
skulls represent the sum total of skulls, save fragments, from
the Triassic deposits of the West. It is, I believe, therefore
safe to assume that A. brachygnatha is a youthful form of A.
browni, and that the lateral line canals really do become more
deeply incised with age, lose the pits from the bottoms of the
canals and become more clearly marked and more closely

connected.
The temporal canal in Anaschisma browni (Fig. 14) is
represented by broken furrows. The portions preserved

exhibit the usual downward tendency of the canal to unite
with the infraorbital on the postorbital element. In its course
forward from the epiotic the temporal canal cuts the squa-
mosal;-a matter of considerable importance to be referred to
later on. The supraorbital canal has an unusually deviating
course in Anaschisma, but aside from the minor twists and
curves it does not differ essentially from the same canal in
other forms. It ends abruptly at the anterior end of the muz-
zle. In its course it gives off the vestige of an antorbital com-
missure which tends to join a vestige from the infraorbital
canal. The jugal canal begins broadly at the very posterior
edge of the skull as though it were continued, as it
undoubtedly was, to the body of the animal. In its course
forward it joins the infraorbital canal on the jugal. The
course of the infraorbital is not unusual in any respect. There
is no anterior commissure on the skull nor is the occipital
cross-commissure developed in either of the specimens. There
are distinct indications of the operculo-mandibular canal on
the mandibles of Anaschisma. Each skull has a mandibular
ramus preserved and the canals are identical on the two rami.
The canal enters the mandible on the surangular and passes
forward around the mandible as described for Diplocaulus.

OO

No. 2.] LATERAL LINE IN EXTINCT AMPHIBIA. 531

Whether or not the canal completed the course around the
mandibles is not to be determined from the specimens at hand.

The close resemblance between the arrangement of the
lateral line canals of Metoposaurus (18), and that already
described for Anaschisma is made evident by a glance at the
figures (Figs. 12,15). This is indicative of the affinity which
the osteology of the two genera exhibits. The forms are,
however, generically distinct as Branson has pointed out, by
the absence of the characteristic ear slit in the latter genus.
The arrangement of the lateral line canals would separate the
forms generically if other characters were lacking. Since
the canals have such a similar arrangement in the two forms
only the differences need be pointed out and the detailed
description given for Anaschisma will serve for Metopo-
saurus. ‘There are no traces of an occipital cross-commissure
in either form, nor indeed have I been able to detect traces of
this canal in but one of the stereospondylous forms. The main
difference between the two forms lies in the absence of con-
nection between the temporal and supraorbital canals (Fig.
i5), and in the more direct course of the latter canal in
Metoposaurus. Other characters are almost identical in
the two groups. The skull of Metoposaurus shows its spe-
cialized characters in the smoothness of the bottoms of the
canals in the anterior part of the skull, and in the canals all
over the skull, being more sharply defined than they are in
Anaschisma.

The skull of Mastodonsaurus giganteus Jeger, fragments
of which were first discovered by Dr. Jeger, in 1824, is the
largest and first known of all of the extinct Amphibia. The
skull reaches, at times, enormous proportions for an amphi-
bian, often attaining a length of four feet with a posterior
breadth of two and one-half feet. The lateral line canals are
clearly marked on all of the skulls known or at least on all
which have been figured (Fig. 16). There are no evidences
of the occipital cross-commissure in an excellent photograph,
published by Fraas (18, PI.I), nor does that author indicate
such a canal in the figure (18, p. 44), he gave of which the

532 MOODIE. ion, Xaaeee

accompanying cut is a copy. The skull of Mastodonsaurus
differs greatly from the other skulls described in the large
size and posterior position of the orbits. This has had an
effect on the arrangement of the lateral line canals. The
temporal canal is deflected strongly downwards and its union
with the infraobital takes place to the side of the eye. The
jugal canal according to Fraas’s figure does not touch the
supratemporal. In fact the canal is not represented in its
most posterior portion. It may have had the course indi-
cated in Fig. 16. The supraorbital is weakly connected with
the jugal and with the temporal canal. It has the usual course
forward and ends near the nares. The only character of
interest in connection with the infraorbital canal is the dis-
tinct bend near the anterior termination as though it were a
remnant of the former connection between the infra- and
supraorbital canals through the intervention of the antorbital
commissure. It is to be noticed that the temporal barely
cuts the outer edge of the squamosal.

The skull of Trematosaurus brauni Burmeister (16) has
already been figured and described in this connection by Baur
and Miall, although the figures given by both of these authors
are inaccurate im detail when compared with the original
drawing of von Meyer. Fritsch in his translation of the re-
port published by Miall also copies his figure and thus con-
tinues the inaccuracies. There is nothing unusual in the
Trematosaurus (Fig. 17) except the strong development of
canals. The occipital cross-commissure is well developed and
is contained within the borders of the epiotics. The temporal
has no connection with the supraorbital and the antorbital
commissure is well developed. There is no anterior com-
missure. It is to be noticed that the squamosal element is
clearly cut by the temporal canal which ends at the ear slit.
It was stated above that there was rarely any evidence of
an occipital cross-commissure in the Stereospondylia but
Trematosaurus seems to be an exception to this rule. There
may be others.

The skull of Anthracosaurus from the Carboniferous of

No. 2.] LATERAL LINE IN EXTINCT AMPHIBIA. 533

Great Britain has been figured and described by Atthey (19).
In regard to the lateral line canals he says: “The mucous-
grooves are two pairs. The anterior pair run backwards and
inwards along the inner side of the naso-lachrymal suture
as far as the posterior margin of the nasals; the posterior are
deeper, and appear in two disconnected portions along the
outer margins of the jugal and quadratojugal bones. The
anterior pair of grooves are less deep and less distinct than
those of Loxomma; the posterior are deeper, wider and
rougher than those of that labyrinthodont.”” The skull studied
by Atthey was in rather poor state of preservation, but it 1s
evident that he detected the anterior portions of the supra-
orbital canals and the jugal canal on one side, with possibly
a portion of the infra-orbital. .He does not indicate the
“mucous-grooves” on his drawing of the skull.

The skull of Loxomma allmanni Huxley (20) is of pecu-
liar interest in connection with the study of the lateral line
system of the extinct Amphibia on account of the presence of
a distinct anterior commissure which extends, clearly marked,
according to the figure given by Embleton and Atthey
(20), between the anterior extremities of the supraorbital
canals. The antorbital commissure is also clearly preserved.
The occipital cross-commissure is not represented in the draw-
ing of Embleton and Atthey nor in that given by Miall (21).
Miall’s representation of the canals of Loxomma is manifestly
inaccurate in regard to the antorbital commissure. In the
skull of Gonioglyptus, Huxley (22) has figured the lateral
line canals as more strongly developed than usual. Unfortu-
nately only fragments of the skull remain. Huxley’s restor-
ation of the lateral line canals in this form is, so far as I can
learn, conjectural. The manner in which the supraorbital
canals curl around the nostril, if such is their normal course
in Gonioglyptus, is without parallel among the other laby-
rinthodonts.

One of the main points to be brought out in this discussion
of the lateral line canals of the extinct Amphibia is the cor-
relation of the cranial elements with those of the fishes so

534 MOODIE. [ VoL. XIX.

far as is possible. Professor Thyng (23), in his study of
the squamosal bone in the tetrapodous Vertebrata, reached
the conclusion that the element usually called squamosal in
the Stegocephala is not that element, but is the supratemporal.
Baur had made the same statement many years previously
when he says: “Das sogenannte ‘Squamosum’ der Stegoce-
phalen (Huxley, Miall, Fritsch, Credner, etc.) ist aber nicht
dieses Element, sondern in Wirklichkeit das supratemporale,
wahrend das ‘supratemporale’ dieser Forscher das Squamo-
sum reprasentirt’ (Baur, Anat. Anz., 1, p: 349). He aitee
ward withdrew from this position (Anat. Anz., Bd. XI, p.
660) and concluded that the squamosal really was that ele-
ment. Thyng now revives this idea and bases his conclusions
on embryological studies of several forms. His major thesis
is not, however, well taken since he assumes it to be an ac-
cepted fact that the quadrate of the lower vertebrates is rep-
resented in the mammals by an element of the ear, the incus.
This is by no means so generally accepted as he would have
us think. His conclusions are briefly these: since the incus
of the mammals represents the quadrate of the lower verte-
brates and since there is an intimate relation between the
incus and the squamosal bone in certain embryos, ergo the
so-called squamosal of the Stegocephala is the supratemporal.
Whatever the element lying next to the parietal may be in
other forms, I am fairly well convinced that in the Stego-
cephala it is the true squamosal and not the supratemporal
(prosquamosal ).

This position is sustained by the study of the lateral line
canals on the crania of the extinct Amphibia and their correla-
tion with those of the fishes. In the skull of Amia the tempo-
ral canal, in its course forward, cuts the squamosal as it does
in all of the Stegocephala examined where the lateral line
canals are preserved. I take the conclusion of Allis, Pollard
and van Wijhe that this element in the fishes is really the
squamosal and the reader is referred to them for their reasons.
In Polypterus according to van Wijhe, when in his dis-
cussion of the lateral line system he says: ““Bedenkt man, dass

No. 2.] LATERAL, LINE IN EXTINCT AMPHIBIA. 535

ein Theil des Hauptastes, namlich der, welcher bei andern
Fischen dem Squamosum zukoniunt, durch das Parietale geht,
dass dieser Knochen auch an der Begrenzung der Gelenk-
pfanne fur das Hyomandibulare theilnimmt, was bei andern
Fischen ebenfalls das Squamosum thut, und endlich dass das
Schadeldach keinen besonderen Knochen besitzt, der auf den
Namen Squamosum Anspruch erheben kann, so ist es kaum
zu bezweifeln, dass der bis jetzt als Parietale bei Polypterus
beschriebene Knochen ein Squamoso-parietale ist,’ the so-
called parietal is the squamoso-parietal. He is followed in
this by Pollard.

I do not find that the arrangement of the canals on the
skull of Polypterus has ever been given in an accurate dia-
gram. Tranquair gives a verbal description of their course
(24). Van Wijhe remarks: “Thren Verlauf (i. e. die Schleim-
kanale in Polypterus) habe ich nicht verfolgt, er ist aber von
Traquair beschrieben” (25). Pollard’s representation is
modified after Wiedersheim and Bautr’s figure is modified after
Pollard. According to Traquair’s description of the course
of the canals, all of these figures are inaccurate in regard to
the course of the main canal. Traquair says the infraorbital
gives off the supraorbital canal on the postfrontal and I have
represented it thus in the diagram (Fig. 3). In Polypterus
according to Traquair the main canal is the infraorbital as
it is in the Stegocephala.

The course taken by the lateral line canals is not subject
to great change. This is suggested by the condition described
for Micrerpeton and Necturus. If the temporal canal, whicn
is the posterior part of the infraorbital canal, cuts a certain
element in one form and cuts the same element with the
same relations in another and related form, it is safe to as-
sume that the element is identical in the two forms. We have
thus a definite basis for conclusions regarding the homolo-
gies of the cranial elements in the two groups; fishes and
stegocephalans. It is easy to understand the correlations
of the premaxillaries, maxillaries, nasals, frontals, prefontals
and parietals of the fishes with the same elements in the

536 MOODIE. [Vov. XIX.

Stegocephala but the correlation of the other elements is
not so definite. Pollard is of the opinion that the post-subor-
ital (postorbital) of fishes is homologous with that of the
Stegocephala and it probably is. Baur was inclined to cor-
relate the epiotics and supraoccipital of the Stegocephala
with the supratemporal elements of the fishes and the ar-
rangement of the lateral line canals substantiates his sug-
gestion. He also would correlate the supratemporal (pro-
squamosal) with the preoperculum of the Amiadiz and the
quadratojugal with the suboperculum. The lateral line canals
of the Stegocephala offer nothing which would contradict
this view, so far as I am aware. The squamosal has been
shown above to be the squamosal of the fishes, so that we
have a nearly complete correlation of the elements of the
Stegocephala with those of the fishes and more especially
the Amia.

Maggi has offered some interesting suggestions with re-
gard to the correlations of the elements of the stegocephalan
skull with those of the higher forms and he would even go
so far as to correlate the epiotics of the Stegocephala with
the interparietal of man (26). While I have no reasons to
doubt his conclusions in regard to some of the correlations
yet I doubt his statements in regard to the cranial structure
of Archegosaurus and Loxomma. If I understand Maggi
correctly his homologies are, in large part, based on the as-
sumption of the fusion of several of the cranial elements in
the Stegocephala. I doubt very much if there has ever
been a true case of the fusion of the cranial elements of the
stegocephalans proved. Jaekel (27) thought he had a case
of such a fusion in the skulls of Diceratosaurus punctolineatus
Cope from the Carboniferous of Ohio, but in a perfect skull
of a closely allied species of this genus I find the elements
all clearly separated, as one would expect. Maggi is also
inclined to doubt, according to Allis, the correlation of the
occipital cross-commissure in the fishes and stegocephalans.
It has been definitely shown above, I believe, that the canals
are homologous in the two groups.

No. 2.] LATERAL LINE IN EXTINCT AMPHIBIA. 537

SUMMARY.

1. There are present on the skulls of the extinct Amphibia
seven distinct lateral line canals, all more or less connected.

2. These canals may be partly homologized with those of
fishes. They may be termed: the anterior commissure,
homologous with the same canal in fishes; the antorbital com-
missure, homologous with the similarly placed canal in fishes;
the infraorbital canal, homologous with that of fishes; the
supraorbital canal, homologous with that of fishes; the tem-
poral canal, homologous with the posterior portion of the in-
fraorbital canal of fishes; the jugal canal, homologous with the
operculo-mandibular (?) and the posterior portion of the
infraorbital (?) canal of fishes; and the occipital cross-com-
missure, homologous with the supra-temporal cross-commis-
sure of fishes.

3. The lateral system has been discovered in four of the
five suborders of the Stegocephala.

4. The Branchiosauria have a type of lateral line on the
tail which is similar to that on the tail of the modern Nec-
turus. The branchiosaurian skull is not grooved by the lat-
eral line canals.

5. In the Microsauria, so far as known, the system of the
lateral line canals is well developed. The occipital cross-
commissure is present on the skulls of at least two genera.

6. In the Temnospondylia the lateral line canals are of a
peculiar type, especially so in the form described, Eryops.
The occipital cross-commissure is well developed.

7. The Stereospondylia always have the lateral line canals
well developed. This character is an indication of age and
specialization. The occipital cross-commissure is present in
a single species of the Stereospondylia.

8. The so-called squamosal bone in the skull of the Stego-
cephala is really that element and not the supratemporal.

9g. The following elements of the stegocephalan cranium
‘are homologous with the same elements in fishes: the pre-
maxille, maxille, nasals, frontals, prefrontals, parietals,
squamosals, and postfrontals. The epiotics and supraocci-

538 MOODIE., [VoL. XIX.

pitals of the Stegocephala are homologous with the supra-
temporal elements of the fishes. The quadratojugal is homol-
ogous with the subopercular of fishes. The supratemporal
(prosquamosal) is homologous with the preoperculum of
fishes.

I am indebted to Dr. Katashi Takahashi for several inter-
esting suggestions in regard to the lateral line system of the
modern Amphibia and more especially Necturus. Dr. S. W.
Williston has, with his usual kindness, read the manuscript
and has offered interesting suggestions. [I am indebted to
him likewise for the use of the material on which the greater
part of this discussion is based. To Dr. Bashford Dean I
am grateful for the loan of the large part of the Newberry
collection of Carboniferous Amphibia belonging to the Ameri-
can Museum.

BIBLIOGRAPHY.

1. Coxtince, W. E., 1894. The Sensory Canal System of Fishes. Part
I,- The ‘Ganoidei.» Q.J.. M.-S., Vol: XXXCV 1, PE 4 pps 400-se5
Pls. 39-40.

M’DonneELL, Ropert, 1862. On the System of the Lateral Lines in
Fishes. Trans. of the Royal Irish Academy, Vol. XXIV, pp.
161-183, Pls. 4-7.

3. Parker, G. H., 1903. The Sense of Hearing in Fishes. American

Naturalist, Vol. XXXVII, pp. 185-204.
Parker, G. H., 1903. Hearing and Allied Senses in Fishes. Bulletin
of the U. S. Fish Commission for 1902, pp. 45-46, Pl. 9.
Parker, G. H., 1904. The Function of the Lateral Line Organs in
Fishes. Bulletin of the Bureau: of Fisheries, Vol. XXIV, pp.
185-207.
4. Dean, Basurorp, 1901. Further Notes on the Relationship of the
Arthrognathi. Memoirs of the New York Academy of Sciences,
Vol iL: Part’ LE Sp-i0rs) FF octate,
5. Pottarp, H. B., 1892. On the Anatomy and Phylogenetic Position of
Polypterus. Zool. Jahrbiicher, Bd. V, pp. 387-428, Pls. 27-30.
Pottarp, H. B., 1892. The Lateral Line System in Siluroids. Zool.
Jahrbiicher, Bd. V; Anat. Heft, 3 and 4; pp. 525-549.
6. Baur, Georce, 1896. The Stegocephali. Anatomischer Anzeiger, Bd.
XI, No. 22, pp. 657-671.
7. Attis, Epwarp P., 1899. On certain Homologies of the Squamosal,
Intercalar, Exoccipital and Extrascapular Bones of Amia calva.
Anatomischer Anzeiger, Bd. 16, Nos. 3 and 4, pp. 49-72.

tN)

S

IO.

Led fe

12.

13.

14.

15.

16.

V7.

18.

10.

20.

25

22.

23.

24.

5 2] LATERAL LINE IN EXTINCT AMPHIBIA. 539

A.tis, Epwarp P., 1889. The Anatomy and Development of the
Lateral Line System in Amia calva. Journal of Morphology, Vol.
II, pp. 463-566.

Moopiz, Roy L., 1909. The Carboniferous Amphibia of North
America. To be published.

CREDNER, HERMANN, 1886. Die Entwicklungsgeschichte von Branch-
tosaurus amblystomus Cred. Zeit. d. Deutsch. Geol. Gesell., p. 576.

THEVENIN, ARMAND, 1906. Amphibiens et Reptiles du Bassin Houil-
ler de France. Annales de Paleontologie, Tome I, pp. 1-19, Pl. 1.

Krnessury, B. F., 1905. The Rank of Necturus among tailed Batra-
chia. Biological Bulletin, Vol. VIII, pp. 67-74.

Krnecssury, B. F., 1905. The Lateral Line System of Sense Organs
in some American Amphibia and some comparison with the
Dipnoans. Trans. of the Amer. Micros. Soc., Vol. XVII, p. 115,
with plates.

Woopwarp, A. SmitH, 1888. Paleontological Contributions to Se-
lachian Morphology. I. On the Lateral Line of Cretaceous Species
of Scylliidae. Proc. Zool. Soc., London, 1888, pp. 126-129.

AnbrEws, C. W., 1895. Note on a Specimen of Keraterpeton Galvani
Huxley from Staffordshire. Geol. Mag., Dec. IV, Vol. II, p. 82.

Von Meyer, HERMANN, 1857. Reptilien aus der Steinkohlenforma-
tion in Deutschland. Paleontographica, Bd. VI, p. 77, for Arche-
gosaurus. Plate XX VII for Trematosaurus.

, Branson, E. B., 1905. Structure and Relationships of the American
Labyrinthondontidae. Journal of Geology, Vol. XIII, No. 7, pp.
568-610, with figures in text.

FrAAS, EBERHARD, 1889. Die Labyrinthodonten der schwabischen
Trias. Paleontographica, Bd. XXXVI, pp. 1-158, with plates.
ATTHEY, THoMAS, 1876. On Anthracosaurus russelli (Huxley). Ann.
and Mag. of Nat’! History, Series 4, Vol. XVIII, p. 148, plate.
EMBLETON AND ATTHEYy, 1874. On the Skull and some other Bones
of Loxomma allmanni. Ann. and Mag. of Natural History, Ser.

4, Vol. XIV, pp. 38-63, PI. 4.

Mirai, L. C., 1874. Report on the Classification of the Labyrin-
thodonts. Report British Assn. Adv. Science, 1874, pp. 149-192,
with plates 4-7.

Huxtey, THomas H. 1865. On a Collection of Vertebrate Fossils
from the Panchet Rocks, Ranigunj, Bengal. Paleontologia
Indies; “Ser TV, Vol. i, Pt 1, pp: 3-24, P 1-6,

Tuyne, F. W., 1906. The Squamosal Bone in Tetrapondous Verte-
brata. Tufts College Studies, Vol. II, No. 2 (Scientific Series),
Pp. 35-73, Pls. 30-42.

Traguair, R. H., 1870. The Cranial Osteology of Polypterus. Journ.
of Anat. and Physiol., Vol. V, pp. 166-183, Pl. 6.

540 MOODIE. [Wor 2S

25. Van WiyHE, J. W., 1882. Ueber das Visceralskelet und die Nerven
des Kopfes der Ganoiden und von Ceratodus. Niederl. Archiv f..
Zool., Bd. V, Heft, No. 3, Juli, 1882, pp. 207-320, with plates.

26. Maccr, Leopoipo, 1897. Placche Osteodermiche interparietali Stego-
cephali e rispondenti Centri di Ossificazione interparietali dell’
Uomo. Reale Inst. Lombard di Sci. e Lett. (2), Vol. XXXI,
PaZiie22o:

Macct, Leopoipo, 1897. Résultats de Recherches morphologiques sur
des Os et des Fontanelles du Crane humain. Archives Italiennes
de Biologie, T. 27, 1897, pp. 230-238.

Macca, Leopotpo, 1898. Autres Résultats de Recherches morpholo-
giques sur des Os craniens et cranio-faciaux et sur des Fontanelles
de ’Homme et d’autres Mammiféres. Archives Italiennes de
Biologie, Tome 30, pp. 161-171.

27. JAEKEL, Orro, 1903. Ueber Ceraterpeton, Diceratosaurus, und Diplo-
caulus. Neues Jahrbuch fiir Mineralogie, etc., Jahrg., 1903, Bd. I,
pp. 109-134, with four plates.

*

Fic. 14—Outline of the larger skull of Anaschisma browni Branson,
showing the distribution of the lateral line canals. Modified after Bran-
son. A little less than one-fifth natural size.

Fic. 15.—Outline of the cranial elements and lateral line canals of
the skull of Metoposaurus diagnosticus von Meyer. Modified after Fraas.
One-fifth natural size.

Fic. 16—Diagram of the cranial elements and the associated lateral
line canals of Mastodonsaurus giganteus Jaeger. After Fraas. One-tenth
natural size.

Fic. 17.—Outline of the arrangement of the lateral line canals and the
cranial elements on the skull of Trematosaurus brauni Burmeister. After
H. von Meyer. Paleontographica, Bd. VI, Pl. XX VII. Two-fifths natural
size.

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THE LARVA OF CTENOPHORA ANGUSTIPENNIS
LOEW.

SOESTER I. ANTHON,
University of Washington.

TABLE OF CONTENTS.

| ELARG\ CSG cece oaee e Se e e E g r 541
EAE Vrman bee by thcenr eters. ote} 0R. 5 oe was Wigs in Geaoee s Secure ee 542
PETC MIptlena Ci Matyas te so ous 4s coc Sebo ce ee 542
Mietuods of hilingcand. Stainificos..|... + <..<<2oo 5. saece aa ee 545
SESE PROV SECM NC en! Nae hy, The thee OSs nthe eee 546
Pitre biccalenu SheMae ay Ste ig. 5 ap. tise Saas a ett oe 551
Bite ml anys OVSUCM iy. esccrik.c 2 .ig Sesw we lecgat ea 0 Lce eee ee 553
LS DISILS CICS) SNR ore RR oe me one ee ee 3 - 554
LUTEESTGIS SEC A vas Siege Ane eee b amu RMane AN Beale ay LCT 2 555
Nervous Tissue ....... Eee RCTs See SPM eb Sane ie Oy RE BM Sl 550
PUIDEN. ct 96: AS cater cs se Re VE TS WR Cease Lach eet | 558
IPISS SO Sood Sac OR Be cee en ee ESE es 0 ee eR me ina Sees cee Rian EE)
LED DS CESEN TM eae er oe ce rae Ar RR Re a nr ORAS EDR ON red 559

I. INTRODUCTION.

The great majority of the Dipterous insects are unfortu-
nately known only in the adult state. This lack of knowledge
in regard to the larval and pupal conditions of many forms
leaves a gap which cannot be filled for some time. _ This gap,
as pointed out by Kellogg, is especially noticeable in the case
of the lower forms in their immature stages, which have
hardly been studied at all. This lack is particularly serious
inasmuch as these are the more generalized forms, and repre-
sent the ancestral types from which the highly specialized
Tipulids have been evolved. It is to these lower forms that
we must look for information regarding the genesis of the
group.

The larva of Ctenophora angustipennis is peculiarly inter-
esting, and as the main anatomical features can readily be
worked out, it offers a most suitable subject for study in
elementary entomology. The chief structural details can even
be made out in observing the live specimen and the larve
can usually be secured in sufficient abundance to furnish plenty
of material.

(541)

542 ANTHON. [VoL. XIX.

Il. Hapitat AND MopE oF LIFE.

Ctenophora larvee are somewhat gregarious in habit and
are usually found massed in runways, as it were, in much
decayed cottonwood or alder logs. They are rarely found
in other logs and never in such great numbers. Where a
single specimen is found a. half hundred or more will com-
monly be found in the same log, though sometimes only a
few will be secured. As the larve require moisture, they
are usually found in the soft, punky wood along the lake
shores. The numerous specimens used in this study were all
secured from the small strip of the Lake Washington shore
on the university campus. The larva probably obtains its
food supply from the bacterial life found in this spongy
wood; as when many of them are kept for some time in
the same material they gradually absorb the plentiful adipose
tissue, which apparently furnishes a reserve food supply.
Numerous protozoan parasites are frequently found in be-
tween the cells of the alimentary canal, especially in the
proventricular czca.

III. DEscrRIPTION OF THE LARVA.

The Ctenophora larva (Fig. 1) is cylindrical, tapering
somewhat towards the hinder end, and is bluntly rounded in
front, especially when the head is much retracted. The larva
is from three-quarters of an inch to a trifle over an inch in
length. There are no external appendages or protuberances,
but the animal is found covered with numerous fine hairs,
extending backwards. When the larva is held to the light,
these cause it to appear yellow on the edges. The larva
moves quite freely by vermiform movements, and these are
possibly facilitated by the presence of the hairs. The body
proper consists of eleven segments, which, with the exception
of the first and last, are not clearly marked off. Most of
these segments are subdivided into annuli, but as the number
of annuli varies in different specimens, and even in the dorsal
and ventral portions of the same individual, their morpholog-

No. 2.] LARVA OF CTENOPHORA ANGUSTIPENNIS. 543

ical value must be slight. The prothoracic segment, the one
just posterior to the head, appears at first sight double, as it is
divided transversely by a distinctly-marked fold. This fold,
however, is merely the result of the very frequent retractions
of the head, which may be completely withdrawn within the
first segment.

Indeed, it is generally so withdrawn, except when the
animal is moving or eating. The head is thus surrounded
by a fold of the body wall which greatly facilitates the retrac-
tion and protrusion of it. The top of the head (Fig. 2) tis
defended by a strong chitinous shield. The occipital region
of this, as is the usual case in the retractile head of the
Dipterous larva, is imperfectly chitinized and is posteriorly
excavated by two deep notches. The antenne (Tig. 3) are
single jointed, projecting a little from the side of the head.
No eyes are visible.

The extreme posterior segment (Figs. 4, 5 and 6) is
modified as usual. The anus opens at the apex of this seg-
ment. Just above the anus and on each side of the median line
are the two large oval stigmata (Fig. 7). The elliptical
central core or plug looks coal black, while the surrounding
ring of irregular chitinous threads is of a deep brown. The
stigmata are of the primitive or generalized type, and are,
therefore, without lips. The aperture can be closed by bring-
ing down the surrounding lobes. The spiracles are sur-
rounded by six backward projecting flexible lobes, four of
these are in a line above the spiracles, while the others are
just below and on each side of the anal opening. When these
are contracted they serve to protect the stigmata, and are
strengthened by the presence of small chitinous patches on
the posterior tips.

As the larval skin is quite transparent, the main body
systems can easily be seen through the skin. If the fat-bodies
are well-developed, as they are just before pupation, they
completely envelop the alimentary canal and therefore the
larva appears white and opaque. When the live animal is
observed the heart can be seen as a delicate pulsating tubule,

544 ANTHON. [Vora

which lies in the median dorsal line, extending from the
second to the extreme segment: The much darker alimen-
tary canal shows on either side of the heart, while the large
lobulated caecum extends two-thirds of the way up the left
side. ‘The superficial tracheal system, which consists of the
two main lateral trunks with their cross-connections, stands
out as slender, shining white strands. On the ventral sur-
face, the ventral ganglia, with their lateral branches, show
very clearly. It is this readiness with which the main ana-
tomical features can be made out that renders Ctenophora
larvee such remarkably fine subjects for students in ento-
mology.

The mouthparts are very complex, and their exact homolo-
gies cannot be accurately determined save by a very extensive
embryological study. The short single-jointed antennz arise
from the small lobe of the plate covering the top of the head.
The antenne bear at their extremity two groups of sensory
papillae. The mentum is triangular, with three serrations on
each side and a larger apical tooth. The mandibles (Fig. 8)
are strong and heavy. On the inner side of each mandible
there is attached the serrated mandibular lacinia, which is
evidently of great importance, as it is so very well developed.
The structure of the maxilla (Fig. 9) is extremely compli-
cated and no definite homologies can be made out. The
lacinia, a row of fine projections, lies next the mentum. On
the outer side a very short palpus shows, and is carried on the
short, curved palpiger. Back of this extends the head sclerites.

The entire body of the larva is covered with fine, close-
set, simple hairs, pointing backwards. These are very much
thicker on the anterior part of the body, and gradually
decrease in number toward the posterior. This fact of dis-
tribution would tend to show that these hairs are somewhat
sensory in function. Besides these there are larger hairs
(Fig. 10), collected here and there in groups of from two to
six and probably sensory in function. These large hairs are
hollow with a central pore canal and are, in common with the
shorter Ones, somewhat useful in locomotion.

No. 2.] LARVA OF CTENOPHORA ANGUSTIPENNIS. 545

The skin is very inelastic and tough, due to the deposit of the
thick chitinous layer. The skin consists primarily of an irregu-
larly curved layer of columnar epithelial cells, the hypodermis.
This layer secretes the chitin, which is laid down in irregularly
waved lamine.

The muscle system is very complex and there are a great
number of muscle bands. There is a wide band of longitudinal
muscles along the side of the dorsal and ventral median line
of the body. Some of the fibers reach from the exterior to the
posterior border of each segment, but other fibers reach from
the middle to either end, and still others reach from the mid-
dle of one segment to the middle of another. There is also
an inner set of lateral transverse muscles. Each muscle is
a bundle of long fibers, each of which is enclosed in an outer
elastic membrane, the sarcolemma. Each fiber is in turn made
up of several fibrillae. The muscle fibers of the insect present
a beautiful striated appearance, which is due to the alternate
light and dark bands of substance. In life the muscles are
colorless and transparent. They are so soft that they are of
a gelatinous consistency.

IV. MetuHops oF KILLING AND STAINING.

Hot Gilson’s fluid was found to be the best reagent for
killing the larve. With this the animals were killed very
quickly and without contraction, while a slower reagent
caused much distortion of the tissues. It was found impos-
sible to make paraffin sections on account of the tearing of the
rest of the section while cutting through the thick chitinous
wall. Excellent preparations may be made by the celloidin
method, although even here there is danger of tearing the
inner delicate tissues. The best stain for use in making out
the general differentiation of the tissues was found to be
Bohmer’s. hematotoxylin. This stain was also used to good
effect in working out the finer histological details, such as the
cell structure of caecum, the finer details of the muscle struc-
tures, and the details of the nervous system. Iron hematoxylin
was found an especially good stain for working out the cell

546 ANTHON. [Vor. XIX.

structure of the salivary gland and the proventricular ceca.
For the differentiation of the muscle plexus of the czecum,
Congo-red was the most satisfactory stain. In preparing
whole mounts of the caecum the best fixation was obtained by
slitting the animal open for a short distance along the side
and at once immersing it in a weak Flemming’s solution.
The best mounts of the mouth parts were made by removing
the organs and cleaning them in strong carbol-xylol with a
little safranin in the clearing solution.

V. THE DIGESTIVE SYSTEM.

The digestive system of Ctenophora is very like that of
Holorusia, the allied giant Tipulid, as described by Kellogg.
(Psyche, June, tg01.) The exceedingly large diverticulum
is characteristic of the vegetable feeding larve of Tipula and
Ctenophora. The alimentary canal extends as a straight tube
from the anterior to the posterior extremity of the body, and
is nearly wholly enclosed in the coiled perforated sheets of
adipose tissue. (Fig. 11.) The tube consists first of the long
slender cesophagus, which opens into the hypopharynx. At
about the middle of this, the cesophagus is embraced by the
circumcesophageal commissures and the brain lobes. At its
posterior end, the cesophagus suddenly dilates and passes into
the proventriculus, whose diameter is about ten times as great
as that of the cesophagus.

The finer structure of the cesophagus, as seen in a cross-
section, differs in the anterior and posterior part of the tube.
(Figs. 12 and 13.) The outer cesophageal layer is composed
of a band of circular muscles, beautifully striated and showing
large oval nuclei. These nuclei extend over several striations.
Within this is a doubtful layer composed of a few strands of
longitudinal muscles, which lie in the cavities formed by the
invagination of the cesophageal epithelium. At places this
epithelium is contiguous with the circular muscles and show
no trace of any longitudinal muscles. Within this muscle
layer is the much convoluted epithelial layer. This is com-

No. 2.] LARVA OF CTENOPHORA ANGUSTIPENNIS. 547

posed of a single layer of columnar cells and is thrown into
numerous, deep, irregular, longitudinal folds, which at times
cause the lumen to be almost closed. The inner margin of the
epithelial layer, unlike that of the epithelium of the ceeca, forms
a straight line. This layer secretes the heavy, inner chitinous
layer, depositing the chitin in irregular laminze. In the anterior
portion of the tube the lumen is nearly filled by the long,
stiff hairs which project into the cavity. (Fig. 14.) These
hairs are entirely lacking in the posterior portion, which is
also distinguished by having no signs of the longitudinal
muscle strands.

The proventriculus comprises the adjoining abruptly dilated
portion. At the point of juncture the cesophagus is sur-
rounded by the fine sphincter muscle, so that the entrance to
the cesophagus may be completely closed and so keep food
from passing back up the cesophagus. (Fig. 15.) There is
also a large cesophageal invagination. This has the same cell
structure as the posterior portion of the cesophagus, and
extends for about the length of the proventriculus, when the
line separating the ventriculus and the proventriculus is taken
to be the beginning of the ventricular ceca. The wall of the
proventriculus is composed of a single layer of secreting
epithelium and is surrounded by a thin muscular membrane.
This membrane is composed of a layer of circular muscles and
an incomplete layer of longitudinal muscle fibers. The epithe-
lial layer shows no signs of great activity as the inner cell
margin is straight and no discharged globules are present.

There is no sharp line of division between the proventriculus
and the vertriculus. The ventriculus proper bears at its
anterior end four elongated pouches, the ventricular czeca.
These are not alike in structure, two of them being nearly twice
as long as the other two. They differ in this respect from
the gastric ceeca of Holorusia, where all four are of the same
size. The longer czeca extend along the ventriculus for about
one-fifth of its entire length. The transition of the epithelium
of the ventriculus to that of the caecum is very sudden.
(Fig. 16.) The epithelium exhibits a very different appear-

548 ANTHON. [Vor. XIX.

ance according to the degree of secreting activity. The cells
of the czeca are evidently very active in secretion and exhibit
many granular protrusions. In the longer ceca there is but
a single layer of cells, while in the shorter ceeca there are two
incomplete layers. (Figs. 17 and 18.) The cells of the
shorter ceeca are evidently much more active and show many
narrow-necked protrusions. These protrusions increase in
size till the cell projects into the lumen; the connection between
the cell and the protrusions constricts, and there results a
separation of the spherical globule. After the globule becomes
free in the lumen it loses its definite outline. (Fig. 19.) The
globule is finely granular, but nowhere contains any sign of
a nucleus, such as described by Needham (Zoological Bul-
letin, 1897) in the digestive epithelium of the dragon-fly
nymphs. The discharged portion of the cell represents but
a small part of the whole and does not contain any trophic
center. The secretion here differs from that of the larva of
Ptychoptera as described by Gehucten (quoted by Packard,
pp. 326-329) for the globule is constricted off and does not
burst through the cell membrane. The process closely resem-
bles that of Collembola, although there are no such marked
changes in cell alveolation. (Folsom and Welles, in the Univ.
of Illinois Bulletin, 1906.) Many protozoan parasites are
found’ in the ceca, being often wedged in, as it were, between
the cells. (Fig. 20.)

Near the posterior termination of the ventriculus are four
very small protruding pockets, the gastric ceca. (Fig. 21.)
These pockets have not been described as occurring in the
nearly allied form, Holorusia. The epithelium here is com-
posed of two layers of cells and is very much convoluted.
The cells are evidently most active and show many protru-
sions and discharged globules.

The termination of the ventriculus is marked by a pale
transverse line and the four coiled Malpighian tubules pass off
at this point. Each tube passes forward to the base of the
ventricular ceeca and then turns backwards. In a cross-section
the tubules show a ring composed of from two to six large

No. 2.] LARVA OF CTENOPHORA ANGUSTIPENNIS. 549

polygonal cells, which have very conspicuous nuclei. The’
excretory canal is clearly marked. (Fig. 22.)

Back of the ventriculus lies the small intestine, which is of
smaller caliber than the ventriculus. The diameter of the
small intestine is only about one-fourth of that of the ventric-
ulus. This opens into the fifth division of the alimentary
canal, the large intestine. The large intestine is distinguished
by the very large intestinal czecum or diverticulum, which is
one of the distinguishing features of the herbivorous Tipulide.
This cecum lies along the ventriculus and extends as far as
the proventriculus. A somewhat similar surface is present in
Holorusia, but it is only about one-third as large. Ona sur-
face view the caecum appears flabby, this being due to the
pouch-like effect produced by the transverse and longitudinal
muscles. The walls of the diverticulum are very thin. The
wall is composed of two layers, an outer one made up of
annular muscles and an inner one composed of very large cells.
(Fig. 23.) (Fig. 24.) The muscles of the diverticulum
form a most peculiar network or muscle plexus, as it might
be called, which in its branching and anastomosing bears a
superficial resemblance to a nerve plexus. (Fig. 25.) There
are eleven or more large bands of striated muscles which
extend around the diverticulum, and these are connected by
numerous finer cross-branches, which are also striated. (Figs.
26 and 27.) In a few places the muscles seem to radiate
from a central mass, but in general the ladder-like appearance
is very marked. The striations run across both the large
muscles and the finer connecting bands, so that the striations
at the junctures meet at right angles. (Fig. 28.) There are
many muscle nuclei, which, on a side view, seem to stand out
from the fiber itself and to be surrounded by a transparent
wall. By means of this peculiar muscle plexus, the diverticu-
lum can be contracted in all directions at once. The gross
structure of the plexus may best be demonstrated by mounting
the entire wall of the caecum after first removing the inner cell
layer by means of a very fine brush. The cellular membrane
is also remarkable. The individual cells are very large and

550 ANTHON. [Vou. XIX.

have very conspicuous nuclei. (Fig. 29.) There is a close
resemblance in structure between the cells of the intestinal
diverticulum and those of the Malpighian tubules. The cells
are but loosely approximated to the muscle walls and in places
the cells are separated by distinct canals. (Fig. 30.) The
nuclei are very large, with deeply staining chromatic filaments.
This large diverticulum, the presence of which characterizes
the herbivorous Tipulids, is excretory in function, though it
may also act as a sort of food reservoir. The similarity of
cell structure with that of the urinary tubules would seem to
point to this conclusion, but besides this there is the additional
evidence of chemical tests. There is a strong uric reaction to
the murexid test, which would seem to show conclusively that
the diverticulum, as well as the Malpighian tubules, is excre-
tory in function.

The large intestine dilates gradually till it forms the rec-
tum. In cross-sections the structure appears very similar to
that of the cesophagus. The epithelial surface is thrown up
into numerous irregular longitudinal folds. The cells are
uniform in size, and show no signs of any activity in secretion.
Within this epithelial layer there is a layer of chitin, which is
thrown jnto irregular folds and laminz. Outside of the epithe-
lial layer there is a series of striated annular muscles, which
extends outwards for a distance equal to about one-fourth of
the central cavity. (Fig. 31.) The structure of the rectum
proper is very much like that of the colon, and the transition
is imperceptible, but here the folds of the columnar epithelium
extend much farther into the lumen and the chitinous layer
is so thick that it almost obliterates the central cavity. The
muscular ring is much thicker, extending out for a distance
equal to the diameter of the lumen. (Fig. 32.) The heavy
muscular walls serve, to retain the food in the absorptive por-
tions of the digestive tract till all possible nutriment has been
extracted.

There is a much coiled salivary gland lying on each side
of the esophagus. (Fig. 33.) Each consists of a greatly
coiled tubule, with a slender collecting duct extending from

No. 2.] LARVA OF CTENOPHORA ANGUSTIPENNIS. 551

the anterior portion. The two collecting ducts unite to form
a common duct which lies just beneath the cesophagus and
opens at the base of the hypopharynx. The glands are hollow,
the walls being only one cell thick. The cell wall consists
merely of an epithelial layer with its intima and basement
membrane. As seen in a surface view the cells are very large
and polygonal in shape. (Fig. 34.) They possess very large
nuclei in which a distinct chromatic filament can easily be made
out by proper staining. The breaking down of the salivary
gland is accompanied apparently by simple cell degeneration,
the “‘selbstandige’’ degeneration of Karawaiew, and therefore
without the recurrence of phagocytosis. The cell nuclei are
at first regularly circular and sharply marked out by a nuclear
membrane, but later on the nucleus loses this membrane.
(Fig. 35.) The histolysis here follows closely the course
described by Kellogg in regard to Holorusia. (Am. Nat.,
1901.) Of course in the case of such a generalized larva as
that of Ctenophora the breakdown of the larval organs would
be accomplished with less change of structure than in the
more specialized forms, which have been largely the forms
studied in this connection, and so there would be less reason
for the occurrence of phagocytosis.

VE Por TRacHvan SYStem

There are two main lateral trachez, one passing along each
side of the medio-dorsal line. These main divisions of the
respiratory system are seen very clearly when looking at the
live larve, and appear as two glistening bands when the animal
is expanded, but having a sinuous course when the animal is
contracted. These two trachez are connected by transverse
and anastomosing branches, one main connecting branch in
each segment. These branches, as well as the lateral tubes,
give off numerous side branches. As these commissures are
connected with the alimentary canal they are very slack, espe-
cially those near the middle of the body. During the vermi-
form movements of the larva, there is a great deal of sliding

52 ANTHON. [Vor. XIX.

on

of the body wall and the alimentary canal, and the commis-
sures must be able to stand the strain.

From these two main lateral branches ramifications pass
off into every part of the body. (Fig. 37.) These branches
pass among the different organs of the body and seem to
serve somewhat as strands to hold them in place. These
branches have very minute ramifications, which become so
attenuated that they pass among the fibers of the muscles.
Each of the main trachez at the anterior extremity breaks up
into a number of fine fibers, most of which are connected with
the brain. In the last segment, just above the hinder part
of the heart, there arises a number of small branches which
are connected with the stigmata.

The lining membrane of the trachez consists of a layer of
polygonal cells fitting closely together as a pavement epithe-
lium. The chitinous wall or intima is thickened at intervals
to form thread-like ridges, the teenidia. These tznidia serve
to keep the tracheze open without affecting their flexibility.

There is but one pair of spiracles so that the larva is
metapneustic, as is the case with nearly all the Tipulide.
The prominent oval spiracles are inserted at the apex of the
last segment, and turn backwards and upwards. The struc-
ture of the spiracles is very similar to that of the larve of
Dicranota and Phalacrocera, as described by Miall and Shel-
ford. (Fig. 38.) The central portion of the spiracle consists
of an inner cone or plug, which is surrounded by a thick and
solid chitinous wall. Outside of this is a chamber with a
colorless chitinous wall, the vestibule. The cavity of the
vestibule is crossed by many radiating fibers, which are irregu-
larly branched and start from the outer wall. Some of the
fibers connect with the inner cone, but many do not reach :t
at all. The stigma forms the outer end of an air chamber
whose inner surface is lined with a zone of large cells. This
region is evidently of great importance in the respiratory
mechanism of the larva, as there are great masses of blood
corpuscles lying about the spiracle. There is a circular mus-
cle with which to draw in the spiracle and help bring the

No. 2.| LARVA OF CTENOPHORA ANGUSTIPENNIS. 553

fleshy protuberances about it. The lateral trachez lost their
teenidia just before they join the floor of the vestibule. The
munute tracheal ramifications which extend out from the sides
of the vestibule are not brought into any direct contact with
the main vessel, but serve rather to aerate the numerous blood
corpuscles. ‘The large trachez lead out from the spiracle and
give off numerous branches to the body wall and viscera.
There is connected with the stigmatic region a very minute
nerve plexus, which helps to show the great importance of this
region in respiration and circulation.

VII. THe CrrcuLatory SYSTEM.

The dorsal vessel or heart is a slender delicate membraneous
tubule which lies along the medio-dorsal line, and extends
from the brain to the last segment. In the live animal this
may be seen to pulsate. The heart is cut off from the body
cavity by the usual diaphragm. This diaphragm extends out-
ward from the heart and, with the dorsal wall of the body,
forms a pericardial chamber. The diaphragm is formed
largely of paired fin-like muscles, the alary muscles, which
extend past the lateral tracheze and connect with the body wall.
There are apparently no ostia, but at intervals the wall is
thickened and the heart is partially divided into a series of
chambers. This lack of ostia is not an aberrant condition, as
there are no ostia present in the very young larva of Musca
(Kolbe). The heart is attached to the body wall by the very
minute suspensory muscles. These are attached to the upper
surface of the heart and radiate till they come in contact with
the body wall.

In a cross-section the heart is somewhat lozenge-shaped.
(Fig. 39.) There are three distinct layers which compose the
heart, as may be seen in a cross-section. There is (1) a very
fine, transparent, and structureless intima, which is not marked
except under a very high magnification, (2) a central layer of
circular muscles, which effect the contraction of the heart, and
(3) there is an extremely thin enveloping layer, the endo-
cardium.

554 ANTHON. [Vo. XIX.

Along the heart on the basal side and along the alary
muscles occur the so-called pericardial cells, which from their
position would seem to have a close relation to the circulation
of the blood. Some cenocytes are at times found collected
along the body wall in the posterior region, as described by
Bengtsonn. According to Kowalevsky the function of the
pericardial cells is to remove the foreign or injurious matter
mingled with the blood. The pericardial cells themselves are
elliptical in shape and with no easily distinguished cell wall.
They often have two nuclei lying side by side in the cytoplasm
and sometimes as many as four without any sign of a sepa-
rating cell wall. The cell-nuclei stain very heavily, but show
no distinct chromatic filaments. The pericardial cells are con-
gregated about the sides of the heart and lie along the alary
muscles for some distance from the heart.

The blood proper is a thin whitish fluid which contains the
very pale oval corpuscles. These corpuscles have a rounded
nucleus and are covered with fat globules. The fresh blood
has a slightly alkaline reaction. These leucocytes are seen in
great numbers at the posterior end of the heart, just in front
of the stigmata. At the stigmata the blood is passed over the
tracheal ramifications, so that it tends to traverse the normal
condition in insects in which the air is always brought to the
blood; while here the blood seems to be brought to the air.

VIII. THe FAtT-BODIES.

The alimentary canal is nearly enclosed in the thin sheet
of adipose tissue, which is perforated by many small holes.
This tissue fills in the space between the other organs and so
occupies a large part of the body cavity. The cells are regu-
larly polygonal in shape, and possess a central oval nucleus.
(Figs. 40 and 41.) The fat-bodies are probably reserve food
material to be used during the rapid pupal metamorphosis, as
the sheets of adipose tissue are very large and conspicuous in
larvee which are about to pupate. When the larvz have been
kept for some time without any adequate food supply the fat-
bodies are gradually absorbed.

No. 2.) LARVA OF CTENOPHORA ANGUSTIPENNIS. 555

IX. THE IMAGINAL Bups.

The imaginal buds are small whitish bud-like bodies which
lie between the muscles and the body wall of the thoracic
segments. There are two pairs of these imaginal buds in each
segment. There are several present on the ventral surface of
the live animal when studied with a hand lens. The ventral
invaginations give rise to the legs, while the dorsal invagina-
tions develop into the pupal respiratory organ, the wing, and
the halterer.

The imaginal buds or histoblasts, which Kellogg suggests
as a better name for these structures, are composed of an
invaginated portion of the hypodermis which has become
folded and in which there has been a special increase of cells.
(Fig. 42.) During this modification, the outer portion of
these cells is separated from the rest and forms the very thick
enveloping membrane, the peripodal membrane. The thick-
ened part of the histoblast is the portion which later becomes
functional as the developed organ. This portion forms two
folds, each fold being composed of several layers of cells. The
so-called tracheal veins lie between the two layers of the func-
tional portion of the histoblast. The peripodal membrane and
the function portion of the bud are both direct outgrowths of
the hypodermis.

There are also other structures which, according to Vil-
lanes, are homologous with the histoblasts; these are the so-
called optic imaginal buds. (Fig. 43.) The eyeless larva, as
is common with the other eyeless Dipterous larve, avoids a
too strong light, and this perception of light through the
integument is probably due to the presence of these optic histo-
blasts. If a ray of light is concentrated on the region of these
optic imaginal buds the response is much quicker than if the
light be concentrated on another part of the body. The optic
imaginal buds are rectangular in shape and are like other
imaginal buds in possessing a peripodal membrane and a wider
functional portion of the histoderm, which later develops into
the optic ganglion. In the central cavity there are several
tracheze and some loose mesodermal tissue.

556 ANTHON. [Vor. XIX.

X. THE NERvouS TISSUE.

The central nervous system extends along the median line
of the ventral surface as a series of ganglia connected by
nerve cords. The ganglia are more closely approximated in
the anterior portion of the chain and some of the ganglia are
united to form the brain. (Fig. 44.) Behind the brain, which
comprises the supra-cesophageal ganglion, there is the sub-
cesophageal ganglion and a chain of ten ganglia. Just back
of the sub-cesophageal ganglion there are four closely approxi-
mated ganglia. These are so closely applied that there is no
connecting nerve cord. Posterior to these, there are six ven-
tral ganglia which are widely separated and are joined by the
slender ventral nerve cord. The ganglia are roughly pyra-
midal in shape and give off four large nerve trunks; two nerve
branches from each side and these soon divide and redivide
into finer and finer branches. The terminal, or tenth ganglion
(Fig. 45), is larger than the others and gives off four large
nerve trunks from the base of the pyramid. The other ganglia
also give off prominent nerve trunks; the one rising from the
basal apex of the ganglion and going to the muscles of the
body wall, while the other, which rises from the middle of the
side of the ganglion, goes to the viscera. The muscular branch
can easily be seen in looking at the live animal. The first
ganglion after the thoracic group lies in the sixth segment, and
posterior to this there is one ganglion in each segment.

The brain proper consists of the supra-cesophageal ganglion,
which lies above the cesophagus and is connected with the sub-
cesophageal ganglion by the cesophageal commissures, so that
the brain completely embraces the cesophagus. (Fig. 46.) In
front of the brain and extending across it is the frontal gan-
glion, which composes a part of the sympathetic system. An-
terior to this and on either side are the optic imaginal buds.
These are small oval swellings of the optic nerve. There are
two other nerves given off from the supra-cesophageal gan-
glion, one going to the antenna, the antennal branch, and the
other running to the labium. Going out from the sub-cesopha-
geal are three branches which connect with the mouth parts.

No. 2.] LARVA OF CTENOPHORA ANGUSTIPENNIS. 557

These serve to control the mandible, maxilla, and the labium,
and are known as the mandibular, maxillary, and the labial
branch.

The brain in its finer structure is exceedingly complex. (Fig.
47.) There are several histological elements, the various cell
elements and the fibrillar or Punktsubstanz. The cell elements
form the cortical portion of the brain, while the central portion
of the brain is composed of minute granules and interlacing
fibers. These fibers appear as cut ends in the sections, so that
the whole medullary portion appears finely granular. In the
cellular portion of the brain there are three distinct kinds of
cells. There is first an outer layer of cortical cells which
differ somewhat in size, but are always larger than the cells
which compose the cell mass lying just within. Then there is
the mass of rather smaller and rounded cells which lie on
either side of the central body and extend almost around the
brain. Among this cell mass may be seen a few very large
cells with very darkly staining nuclei. These evidently rep-
resent the large motor cells described by Kenyon in his work
on the brain of the bee. The same elements may be found in
the sub-cesophageal ganglion, although there is not so much
definiteness in limiting the cell mass and there are fewer of the
large cells. (Fig. 48.) There is here, in common with other
Dipterous larvee, no sign of the complicated mushroom bodies.
In the sub-cesophageal ganglion there is a greater amount of
the Punktsubstanz in proportion to the size than there is in the
supra-cesophageal ganglion.

The thoracic and ventral ganglia show the same histological
elements as the brain. (Figs. 49-50.) The arrangement of
these elements is in general the same. There is an outer
cortex layer of cells, the inner portion is composed of the cell
mass with a few large cells interspersed, and a central portion
which is composed of the Punktsubstanz. This arrangement
is common to both the ventral and thoracic ganglia. Each
nerve consists of an axis cylinder, which has a striated appear-
ance in a longitudinal section which is due to the fine fibrillz,
and then the enveloping membrane or neurilemma (Fig. 51).

558 ANTHON. [Vou. XIX.

Xlwuvithe-eoPs

When the larva reaches its full size, it has stored up a great
amount of reserve food material in the sheets of adipose tissue ;
it ceases to feed and becomes very sluggish until the last larval
skin is shed and the pupa emerges. Pupation here usually
takes place some time in April. The pupa is shorter than the
larva and is proportionately wider. (Fig. 52.) When it first
emerges it is very soft and very transparent, but as the parts
becomes chitinized they turn a rich brown. The compound
eyes, antenne, the labial palps and other mouth parts can be
seen through the pupal skin, though the head is not marked off
from the rest of the body. The three pairs of thoracic legs
are short and do not reach beyond the first abdominal segment.
The abdominal portion consists of the usual six segments, pure
white save for the dark golden band down the ventral and
lateral surfaces. On each of the lateral lines there are two
brown projections, a large one near the posterior portion of
the segment and a smaller one midway. On each median sur-
face there are others; one on each side in the first two abdom-
inal segments and two in the next four. The posterior seg-
ment is, of course, sexually modified. The tracheal system of
the pupa is closed, as there are no spiracles present.

Since the posterior extremity is changed to conform to the
corresponding segments of the adult, the sexual modifications
are indicated. The female may at once be recognized by the
long triangular valves which are to constitute the ovipositor.
The posterior segment of the male shows no such modifica-
tion, but ends bluntly and shows the transverse anal opening.
There are three large lateral spines upon each side of the
posterior segment, while the other segments only have one
large and one small projection. The spines all project back-
wards and serve to assist the animal in locomotion by giving
it sufficient hold in the soft wood in which the pupa lies. It
also enables it to creep to the surface before its final transfor-
mation. Such aids are found in very many Dipterous larve
and Dipterous pupe, for example in Dicranota, Tipula, and
Bibio. If the pupa could not come to the surface befgre the

No. 2.))° LARVA OF CTENOPHORA: ANGUSTIPENNIS. 559

emergence of the fly much damage would inevitably result
and a perfect adult would be rare indeed. If the pupa is
extracted from its burrow it very shortly establishes itself in
an equaly convenient position just beneath the surface.

bk. Tae iia

The fly emerges toward the end of April or the beginning
of May, and is a very handsome fellow with his gay coloring
of red, brown, or yellow. (Fig. 53.) The distinctive feature
of the crane-flies, according to Comstock, is the presence of
the transverse V-shaped suture, and this feature is very
marked in this species. The wings are long and narrow, with
a characteristic venation, the veins being partially fused at the
proximal end. The ovipositor is composed of two long, horny
pointed valves, well fitted for depositing the egg in firm sub-
stances. The power of flight is not well developed and the
ability to walk is also poor. The long legs are so feebly
attached to the body that they are easily broken off. This
species of Ctenophora ranges from Vancouver Island to Cali-
fornia. In conclusion I wish to express my indebtedness to
Prof. Trevor Kincaid, of the University of Washington, with-
out whose aid and encouragement this paper would have suf-
fered a great deal.

BIBLIOGRAPHY.

1. BENGTSONN, S. Ueber sogen, Herzkorper bei Insekten-larven, zu-
gleich ein Beitrag zur Kentniss der Blutgewebe. Stockholm, 1880.

2. Comstock, J. H., and NeepHam, J. G. Wings of Insects. Am.
Nat., November, 1880.

3. Dewi, J. A. Structure and Life History of Psychoda sexpunctata.
Trans. Ent. Soc., London, October, 1905.

4. Fotsom, J. W., and Wettes, M. W. Epithelial Degeneration, Re-
generation and Secretion in the Mid-Intestine of Collembola.
Univ. of Ill. Bulletin, Vol. IV, No. 6.

5. Forsom, J. W. Entomology, with reference to its Biological and
Economic Aspects. Blakiston, 1906.

6. Frocet, J. H. S. Ueber den einheitlichen Bau des Gehirns in den
verschiedenen Insecten Ordnungen. Zeitschr. f. wiss. Zoologie,

1878.

IO.

21.

ANTHON. [Vor. XIX.

Graber, D. Ueber die Blutkorperchen der Insekten. Sitzb. Akad.
Wiss., Wien, 1871.

Kettocc, V. L. Histoblasts of the Wings and Legs of the Giant
Crane-fly. Psyche, September, 1901.

Kettocc, V. L. Anatomy of the Larva of the Giant Crane-fly.
Psyche, June, 1901.

Kettocc, V. L. Development and Homologies of the Mouth-parts
of Insects. Am. Nat., 1902.

Knuppet, A. Ueber Speicheldriisen von Insekten. Berlin, 1887.

Kose, H. J. Einftthrung in die Kentniss der Insekten. Berlin, 1893.

KrancHer, O. Der Bau der Stigmen bei den Insekten. Leipzig,
1881.

Miatt, L. C. Dicranota, a Carnivorous Tipulid Larva. Trans. Ent.”
Soc., London, September, 1893.

Miatt, L. C., and Suetrorp, R. History of Phalacrocera replicata.
Trans. Ent. Soc., London, April, 1897.

NEEDHAM, J. G. The Digestive Epithelium of the Dragon-fly
Nymphs. Zoological Bulletin, 1897.

Packxarp, A. S. A Text-book of Entomology. Macmillan, 1889.

PLATEAU, F. Les phenomenes de la digestion chez les insects. Acad.
roy. Belgique, 1874.

Pratt, H. S. The Embryonic History of the Imaginal Discs. Bost.
Se. of Nat. Hist., Vol; X XIX, No, 13. -

Vrattanes, M. H. Recherches sur l’histologie des Insectes. Ann.
Sc. Nat. Zool., Aout, 1882.

Viattanes, M, H. Le Ganglion Optique de quelques Larves de
Dipteres. Ebenda, 1886.

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LIST OF ILLUSTRATIONS.

Fic. 1.—Larva. he., head; tr., trachea; ht., heart; al., alimentary canal;
st., stigma; an., anus.

Fic. 2.—Surface view of head. an., antenna.
Fic. 3—Antenna, H. P. sp., sensory papille.
Fic. 4.—Posterior extremity of male pupa.

Fic. 5.—Side view of posterior extremity. st., stigmata; sp., projec-
tions; an., anus.

Fic. 6.—Face view of posterior extremity. st., stigmata; sp., projec-
tions; an., anus.

Fic. 7-—Surface view of spiracle. c., central core; v.,° vestibule;
cb., cross-branches.

Fic. 8—Mandible. mp., mandible proper; ml., mandibular lacinia.

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Fic. 6.—Maxille. la. lacinia; ps... palpus; pr: palpiger; sc ead
sclerites; me., mentum.

Fic. 10.—Large sensory hairs.

Fic. 11.—Surface view of alimentary canal. p., pharynx; o., cesoph-
agus; pr., proventriculus; lc. long proventricular cecum; sc.. short
proventricular cecum; g., gastric cecum; v., ventriculus; m. Malpighian
tubules; d., diverticulum; li., large intestine; r., rectum.

Fic. 12.—Cross-section of anterior cesophagus. mw., muscle wall;
se., secretory epithelium; ch., chitinous layer; p., projecting hairs; im.,
inner muscle fibers.

Fic. 13-—Cross-section of posterior cesophagus. mn., muscle nucleus;
mw., muscle wall, se., secreting epithelium; ch. chitinous layer.

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Fic. 14.—Cross-section of anterior cesophagus to show the difference
in the development of the chitin and hairs. se., secreting epithelium;
ch., chitinous layer; p., projecting hairs.

Fic. 15.—Longitudinal section of cesophageal invagination. ch., chitin;
e., epithelial layer; m., muscle layer; s., sphincter muscle; ov., ceso-
phageal valve; me., mesoderm.

Fic. 16.—Longitudinal section of cesophagus and small cecum. e., epi-
thelium of stomach; as., active secreting epithelium; mw., muscle wall.

Fic. 17.—Cross-section of large ventricular cecum. mw., muscle wall;
se., secreting epithelium; sg., secreted globule.

Fic. 18—Cross-section of small ventricular cecum. mw., muscle wall;
se., secreting epithelium; s., secretion thrown off.

Fic. 19.—Wall of ventricular caecum to show active secretion.

Fic. 20.—Central cross-section. h., heart; ls., large ventricular cecum;
ss., small ventricular cecum; a., alimentary canal; f., fat bodies.

LARVA OF CTENOPHORA ANGUSTIPENNIS

ANTHON

SOESTER I.

JOURNAL OF MORPHOLOGY--VOL. XIX, NO. 2

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Fic. 21.—Posterior cross-section. h., heart; c., gastric cecum; m., Mal-
pighian tubule; t., trachea; f., fat bodies; d., intestinal diverticulum.

Fic. 22—Longitudinal section of Malpighian tubule, to show the
similarity of cell elements.

Fic. 23.—Cross-section of wall of diverticulum. m., muscle wall;
c., cell layer.

Fic. 24.—Cross-section of cell of diverticulum.

LARVA OF CTENOPHORA ANGUSTIPENNIS

ANTHON

SOESTER I.

Fig. 22

Fig. 24

NAL OF MORPHOLOGY--VOL. XIX, NO. 2

Fic. 25.—Muscle plexus of the diverticulum.

LARVA OF CTENOPHORA ANGUSTIPENNIS
SOESTER |. ANTHON

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Fic. 26.—Muscle coat of diverticulum, H. P.

Fic. 27.—Same, L. P.

Fic. 28.—Muscle network from diverticulum.

Fic. 29.—Cell element from diverticulum.

Fic. 30.—Surface view of cell membrane of diverticulum.

Fic. 31.—Cross-section of colon. mw., muscle wall; se., epithelium;
ch., chitinous wall. ’

Fic. 32.—Cross-section of rectum. Same as in Fig. 29.

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Fic. 33.—Surface view of salivary gland. d., common duct; dc. col-
lecting duct; g., gland proper.

Fic. 34.—Surface view of salivary gland. n., cell nucleus; cb., cell
boundary; c., cells.

Fic. 35.—Cross-section of salivary gland (showing histolysis). n., cell
nucleus.

Fic. 36.—Surface view of tracheal system. ad., anterior ramifications;
mt., main lateral trunks; ct., cross branches; |b. lateral branches; pd., pos-
terior ramifications.

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SOESTER !. ANTHON

ARVA OF CTENOPHORA ANGUSTIPENNIS

XURNAL OF MORPHOLOGY-—-VOL. XIX, NO. 2

Fic. 38.—Longitudinal section of spiracle. o0., opening; cm., closing
muscle; d., divisions of branches; be., blood corpuscles.

Fic. 39.—Cross-section of héart. em., enveloping membrane; sm., sus-
pensory muscles; 1., leucocytes; am., alary muscles; i., intima; ml., mus-
cular layer.

Fic. 40.—Closer adipose tissue.
Fic. 41—Open adipose tissue.

Fic. 42.—Imaginal buds. c., cuticle; ch., chitin; t., trachea; pm., peri-
podal membrane; tv., tracheal vein; h., hypoderm; pv., peripodal vein;
w., wing—forming part of histoblast.

Fic. 43.—Optic imaginal disc. e., endoderm; t., trachea; m., mesoderm,

Fics. 44 and 45.—Surface view of central nervous system. fg., frontal
ganglion; og., optic ganglion; lan., nerve to labium; an., antennal nerve;
br., brain; sym., branch of sympathetic nervous system; c., commissures ;
sg., subcesophageal ganglion; mn., nerve to mandible; mxn., nerve to
maxilla; Ibn., nerve to labium; tg., thoracic ganglion; vg., ventral ganglion.

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Fic. 46.—Anterior cross-section of body. h., heart; f., fat-bodies;
b., brain; o., oesophagus; s., salivary gland; sy., sympathetic nervous
system; tm., transverse muscles; lm., longitudinal muscles; sk., skin.

Fic. 47.—Section of brain (transverse). me., large cells; cm., cell
mass; br., brain; ps., punktsubstanz; cc., cortical cells; ce., cesophagus;
sym., sympathetic system; tr., trachea; sg., sub-cesophageal ganglion.

Fic. 48.—Cross-section of thoracic ganglion. Same notation as Fig. 50.
Fic. 49.—Cross-section of ventral ganglion. Same notation as Fig. 50.

Fic. 50.—Longitudinal section of chain ganglia. lc., large cells; ps.,
punktsubstanz; cm., cell mass; cc., cortical cells; ax., axis cylinder;
nu., neurilemma.

Fic. 51.—Peripheral nerve plexus. ax., axis cylinder; nu., neurilemma;
n., nucleus.

Fic. 52.—Pupa, female.

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JOURNAL OF MORPHOLOGY, VOL. XIX, NO. 2

LARVA OF CTENOPHORA ANGUSTIPENNIS
SOESTER I. ANTHON

JOURNAL OF MORPHOLOGY--VOL. XIX, NO. 2

CONTRIBUTIONS FROM THE ZOOLOGICAL LABORATORY OF THE MUSEUM OF
COMPARATIVE ZOOLOGY AT Harvarp CoLiece, E. L. Marx, Director.—
No. 108.

THE VISUAL CELLS IN VERTEBRATES, CHIEFLY
IN NECTURUS MACULOSUS.

ARTHUR Day HOWARD.

ke HISTORICAL INTRODUCTION:

From the earliest recognition of the layer of rods and cones
as the receptive portion of the optic apparatus, this portion
of the retina has naturally received considerable attention.
The history of these researches has been quite fully dealt with
by a number of writers. Of these I would mention Schultze
(722), Hoffman (75), Schwalbe (87), Krause (’92), Greef
(00), aud Elesse (:04 ).

Treviranus (’36), and after him Gottsche (’36) and Henle
(739), were among the earliest to declare the layer of rods and
cones to be the expansion of the optic nerve. ‘The error of
believing that the “Sehpapillen” were turned toward the light,
was corrected by Michaelis (°37), who first called attention
to the fact that the rods formed the outermost layer of the
retina. This discovery was confirmed by Bidder ('39) and
Hannover (’40), but both believed that the rods could have
no nervous function. Brticke (’44) agreed with Bidder and
with Hannover in considering the rods to be refractive bodies
for the transmission of light returning by reflection from the
choroid.

The classic investigations of Heinrich Miller (’52; °56) and
Kolliker (’52) helped to bring into general acceptance the
belief that the rods and cones are the light-receptive organs
of the retina. One of the grounds upon which Kolliker based
his conclusion, was the similarity in structure, as he considered
it, between nerves and rods. He says (p. 328): “Was die

562 HOWARD. [VoLt. XIX.

Stibchen selbst anlangt, so scheint mir aus ihrem Verhalten
im frischen Zustande, ihrer leichten Veranderlichkeit und ihrer
Reaction gegen Wasser und andere Substanzen unwiderleglich
zu folgen, dass dieselben mit andern, blassen Nervenrohren,
namentlich den Opticusfasern in der Retina, auf eine Stufe zu
stellen sind und die Natur von zarten, mit einem zahflussigen
eiweissreichen und auch fettfuhrenden Inhalt erfullten Rohren
besitzen.”’ And he further adds (p. 329): “Eine wesentliche
Differenz zwischen den Stabchen und blassen Nervenrohren
kenne ich nicht.”

Kolliker by this declaration took the position, held jor years
by Henle, of identifying the rods with the axis cylinder (“Ner-
venrohren”’).. Leydig (755; ’64) also declared the rods and
cones of vertebrates to be “eigenthtmliche Umwandlungen der
Nervensubstanz.”’ The investigations of Max Schultze (66;
71) cleared up many points in the structure of the rods and
cones. Through these researches the contention of H. Muller
and Kolliker was sustained.

The results of Schultze’s researches and those of the workers
up to his time, with regard to the structure of the visual cells,
is well summarized in the following account, taken in the
main from Hoffmann (’75). The description is based upon
the amphibian rods and cones, which on account of their large
size have yielded more results to investigation than those of
any other animals.

The Rods consist of two parts, chemically and physically
different, named the inner and outer segments or limbs. The
outer segment is strongly refractive while the inner one con-
sists of a homogeneous substance much less refractive. The
segments are clearly distinguishable one from the other. What
is evident in the fresh condition is especially marked after
treatment with osmic acid. This reagent colors the outer seg-
ment black, while the inner one remains colorless or assumes
a greyish shade. The reaction to (or behavior in) water, dilute
acids, and alkalis is totally different for the two segments.

Valentine (’62) and Max Schultze (’67) found that the

No. 3.] VISUAL CEELS CIN. VERTEBRATES. 563

outer segments are doubly refractive, while no trace of this
was to be seen in the inner ones. Tests of outer segments or
rods from the frog with a polarizing microscope, employing
a gypsum interference plate, determined an optical axis in the
length of the rod and that the rod has positive double refrac-
tion with respect to this axis. Preparations of frog retinas
so disposed as to permit the light to pass through the length
of the rod, show that in this axis no double refraction takes
place.

The rods of amphibians are notable for their size, the dimen-
sions of some in micra being as follows:

Outer Segment. Inner Segment.
Length. Breadth. Length.
GCN mcsieayeteneee VOL 6 19
UN 0); ae APS i? Rae 24-28 12 15-16
TMG Oe a ee a 40-45 8 16-20
Bufo variabilis °..... 76 8 17
Sailenaneyavaliely Coe or oc 44 12 18

Outer Segment.—In form the outer segment is cylindrical
with a hemispherical slightly bulging distal end. Under high
magnification its outer surface is marked by parallel striations,
which deviate from a strictly longitudinal course only in that
they are very slightly spiral. This appearance is due to super-
ficial furrows alternating with ridges. The form of the outer
segment may thus be well compared to that of a column with
a slightly spiral fluting. The striations according to Schultze
(724) have some relation with a deeper differentiation in
structure, for in separated laminae, in addition to the grooving
of the surface, there is a suggestion of a radial division of the
substance.

Another character of the outer segment of the rod is the
transverse banding, which appears at regular intervals. This
is seen to best advantage by very oblique illumination of fresh
preparations (Schultze, *69>, p. 380) and is a surface indi-
cation of a plate-like structure. The thickness of the plates
in micra according to the measurements of Schultze (’67)
and Zenker (’67) is as follows: frog .5;—.6, triton .55—.6,

564 HOWARD. [VoL. XIX.

salamander .6, dove .62, guinea pig .88, man .45—.0 (Greef
:00). The thickness is constant for a given species and shows
little variation even in the whole vertebrate series. Between
the plates is a cementing substance, which becomes greenish
instead of black in osmic acid. This cement is affected rapidly
by certain reagents, and owing to its swelling it causes a char-
acteristic disintegration of the outer segment into discs. This
disintegration occurs earlier at the distal end of the segment
than at the proximal, the difference being due to a protecting
sheath over the latter.

The presence of an axial fibre in the outer limb, as main-
tained by Ritter (’59) and later called “Ritter’s fibre,” was
questioned. Manz (’61; ’66) and Hensen (’67), however,
sided with Ritter; but Max Schultze concluded from Zenker’s
study of the refractive indices of these parts, that the appear-
ance was due to a difference in refrangibility between the
sheath and the substance of the rod. It was probably this
opinion of Schultze which was responsible for the general
discredit which “Ritter’s fibre” eventually met with.

Inner Segment.—The inner segments of the rods in amphi-
bians are usually short but as wide as the outer ones. In
perfectly fresh condition the substance of the inner segment is
homogeneous. Very soon after a preparation is made, how-
ever, a cloudiness appears, which seems to be due to coagulation
granules. In the toad and frog there is observable near the
edge of the outer segment a characteristic body in the form
of a plano-parabolic lens. This body, which in fishes, other
amphibians, and birds is much broader, was given the name
“lens-shaped body” by M. Shultze, and later was called “ellip-
soid” by Krause, and “outer-lens” by H. Virchow. The ellip-
soid turns brown with osmic acid. It is more strongly differ-
entiated by further treatment with fuchsin. With this stain
the outer limb, as well as the ellipsoid, becomes a dark red
while the remainder of the inner limb is light red. A more
complicated condition is found in some forms (Triton, Sala-
mandra), in which there are present two lens-like bodies having

No. 3.] VISUAL CELLS IN VERTEBRATES. 565

the relation of the lenses in a compound achromatic objective,
a proximal bi-convex body fitting into a distal plano-concave
one. In osmic acid the plano-concave body is colored brown
like the ellipsoid in other forms, and it also becomes dark red
with fuchsin. On the other hand, the bi-convex body stains
like the remainder of the inner segment. This body was
called the “paraboloid” by Krause. In the fresh condition the
plano-concave part, or ellipsoid, is finely granular, while the
paraboloid is completely homogeneous. According to Max
Schultze the paraboloid may be isolated.

The channeling of the outer surface of the inner segment,
as reported by Merkel (’70), was not credited, and another
question in dispute was the presence or absence of a membrane
enveloping the segment. Landolt (71) and Merkel reported
its presence, while Max Schultze claimed that there Was no
distinct membrane, but that fibrous projections from Miiller’s
fibres extended over the inner segment and the proximal third
of the other segment. Schultze was at one time disposed to
consider these as nerve fibrils, but was led finally to the view
last given. He says (’72b, p. 823): “Although the fine fibres
are with difficulty traced backwards into the external granule ©
layer, I have ascertained this much with certainty, namely,
that they are continuous with the tissue lying between the
fibres of the rods and cones. But since this tissue can only be
considered as connective substance, the fibrils in question rep-
resent a continuation of the delicate fibrillated connective sub-
stance of the external granule layer, and form supporting
fibrillar framework for the bases of the rods and cones (Comp.
nies 26) 4

The Cones have parts corresponding to those in the rods,
and these parts in general show similar reactions both to
chemical reagents and to light. In amphibians the difference
between the other segments of the rods and cones in these
respects is less marked. The conical outer segments possess
channeling of the outer surface, as in the rods, but with
grooves nearer together. The outer segments of the cone are

5606 HOWARD. [VoL. XIX.

exceedingly unstable and show the same plate-like structure
as the rods, but owing “to a sheath the disintegration is not
as rapid. This fibrillar sheath in the cones, as in the rods,
is easily demonstrated to be a prolongation from the inner
segment. This inner segment shows the same complexity as
that of the rods, possessing a distal ellipsoid (linsenformigen
Korper) and a proximal paraboloid (“blassere innere
Halfte’). In the frog and also in Sauropsida generally, there
is present between the outer segment and the ellipsoid a
highly refractive, colored, spherical body called the oil globule
(“pigment Kugel’). Max Schultze (722, p. 1003) found
internal longitudinal fibres, in addition to peripheral fibrils,
occupying the whole thickness of the inner segment of the cone
in man. He was able to follow these from the beginning of
the outer segment to a point short of the external membrane.
Their further connections he was unable to make out.
Nuclet.—While in fishes and mammals the nuclei of the rods
differ from those of the cones, in amphibians conspicuous
differences are not apparent. The nuclei are arranged in two
layers in both Rana and Bufo, but in a single layer in Triton
and Salamandra. In frogs and toads the nuclei of the rods
are commonly close to the external limiting membrane, while
those of the cone cells are crowded into the second layer.
Hoffmann (’75) described a thin granular cytoplasmic sheath
about the nuclei and says there is a proximal extension (cone-
foot) of the sheath into the outer granular layer. This exten-
sion possesses, according to somewhat inconstant appearances,
a terminal spherule having a rough or ragged surface.
Double Cones, first described by Hanover (’40), are found
in all vertebrates except mammals. They consist of two cones
applied along a part of their lateral surfaces. In Amphibia
as well as in Sauropsida there is a conspicuous difference
between the cones of a pair. One of these is longer and egg-
shaped, it is called by German authors the ‘“Haupt-zapfen:”
the other is shorter and retort-shaped, it is known as the “Neb-
en-zapfen.” In triton the Haupt-zapfen possess ellipsoids only,

No. 3.] VISUAL CELLS TIN VERTEBRATES. 567

the Neben-zapfen both ellipsoids and paraboloids. Hoffmann
(*75) expressed doubt as to whether the double cones possess
one or two nuclei, but inclines to the latter view. Schultze
seemed to favor the former. He states (Schafer ’97, p. 49) that
twin-cones possess two feet, one straight, the other oblique.

The investigators whose results are summarized in the fore-
going account carried the analysis of the structure of rods and
cones so far that for twenty-five years almost no noteworthy
advance was recorded. Many of the structural features dis-
covered by them seemed hardly to accord with the conception
of the rods and cones as modified nerve fibres. The plate
structure of the outer segments was generally considered as
strong evidence against this view. M. Schultze (’71, p. 257),
however, seemed disinclined to give up the older notion. He
says: “Es ist das Wahrscheinlichste, dass Nervensubstanz
auch mit den Aussengliedern in Contact oder Continuitat
stehe.”’ However, he admits (’72°, p. 1006) the possibility
of a non-nervous function for the outer segment: ‘“‘Somit
konnte moglicher Weise die Nervensubstanz mit den Innenglie-
dern abschliessen und das Aussenglied einen nicht nervosen
physikalischen Hulfsapparat darstellen.”” He considered it
probable that the outer segment, through its laminz, serves as
a reflecting apparatus and that the transformation of the lumin-
ous rays into nerve impulses is effected in this region. These
views were strengthened by his studies on invertebrates, where
the laminated visual rods in mollusks and arthropods were con-
sidered to be analogous to those in vertebrates.

Many writers on invertebrates, especially on arthropods,
e. g., Hensen (’65) and Watase (’go), believed that the visual
cells were largely cuticular in structure. Thus Schultze’s
comparison apparently led other students to the assumption
that the outer segment of the vertebrate visual cell was in
the nature of an “Abscheidungsproduct”’ or cuticular substance,
and this view was held to be supported by embryological
evidence. Although Schultze seems to have given expression

568 HOWARD. [Vov. XIX.

to no such view, his results were so interpreted by others,
e. g., Schwalbe. This idea of the cuticular nature of the outer
segments has met with general acceptance and has remained
as authoritative almost up to the present day. Thus one finds
frequently in text-books, where the outer segment alone is
referred to, such expressions as: “entspricht einer Cuticular-
bildung” (Schwalbe, ’87, p. 104), and “der Ausdruck einer
kutikularen Auflagerung” (Rauber, :03, p. 810). Or the
entire rod, or cone, is called a “Cuticularenbildung” (Wieder-
sheim, ’86), an ‘“Abscheideproduct” (Gegenbaur, ’98, p. 935).

From time to time there have appeared in the literature
on the retina results quite out of the ordinary, whose non-
acceptance may be attributed to lack of confirmation by others,
or to obvious insufficiency of evidence. The position, for
instance, taken by Borysiekiewicz (’87), that rods and cones
are non-nervous, seems to have received little support. Norris
and Wallach (’94) describe “Distal connecting loops between
visual cells.” The photographs which they publish, to illus-
trate this condition, are certainly not convincing. Johnson
(95) finds a “branching central fibre” in the visual cell. Pes
(:00) maintains that the ellipsoid acts as a nucleus. Bernard
( : 00-03) considers the visual cells to be vesicular projections
from a syncytial retina.

The slow advance in the study of the retina since Schultze’s
time would seem at first sight rather strange in the light of
recent progress in cytological technique. It might be partially
accounted for, however, by the fact, that, owing to the extreme
delicacy and instability of the rods and cones, many recently
devised neurological methods are inapplicable.

In noticeable contrast with the condition of the problem
in vertebrates has been the progress in the study of the ter-
minal visual organs of invertebrates. In the arthropods, for
instance, the rhabdomes, which were supposed by earlier writers
(Hensen, ’65; Grenacher, "79; Watase, ‘90) to have been
formed by secretions, have been found by later workers to be
living tissue of marvellous complexity. Schultze (’724), who

No. 3.] VISUAL. CELLS IN GERTEBRATES. 5690

found a fibrous structure in the molluscan visual cell, surmised
a like structure in arthropods. Later, fibres were actually
observed by Patten (’86) and others, and it was demonstrated
by Parker (’95) that in the rhabdomes of the crayfish the
fibrils composing them are neurofibrils and that the substance
of the rhabdome is more correctly described as differentiated
living material, comparable to the contractile substance of
a muscle fibre, than as a secretion. This view, that the
rhabdome is composed of neurofibrils, has been greatly
extended for the invertebrates by the recent work of Hesse
C2008 5,01):

In the light of these discoveries in the lower animals it is
not surprising that the attention of investigators should be
drawn again to the more difficult problem of the finer structure
of the rods and cones in vertebrates. That an interest exists,
may be readily seen by reference to the literature of the last
five years in comparison with that of the twenty years previous.

Another incentive to research in this direction is to be found,
no doubt, in the interest aroused by the discoveries of Apathy
(97) as to the minute structure of the nervous system. The
further exploration of the nervous elements through the
researches of Bethe (’98), Prentiss (: 03), Schneider. (:.02),
Parker (’95), Nissl (: 01), Embden (: 01) and others brings
up, as a pertinent problem, the determination of neurofibrils
in terminal sense-cells. Moreover, where these are found, is
raised the question of their relation to other intra- and inter-
cellular fibrils.

Schneider (:02) is, so far as I know, the first author since
the appearance of Apathy’s paper to claim an identification
of neurofibrils in the rods and cones of vertebrates. He used
the frog in his studies; concerning the longitudinal markings,
about which there has been so much controversy, he says
(p. 789) : “Das Sarc der Sehzellen ist zart langsfadig struiert;
wir haben die leicht geschlangelt verlaufenden Faden als
Neurofibrillen aufzufassen.” These neurofibrils he considers
as continuous from the cell foot in the outer reticular layer

570 HOWARD. [Vou. XIX.

to the distal end of the outer segment, which is turned towards
the pigment cells. In the red rods, the fibres are described
as peripheral, starting from the rod foot and extending over
the nucleus in the thin mantel sheath. Between the nucleus
and external limiting membrane, they form a loose fibril group,
but on reaching the membrane they become entirely peripheral,
lying in the sheath of the inner and outer segments for the
rest of their course. A granular cone proximal to the ellipsoid
may be a new feature for the inner limb, but is probably
identifiable with the paraboloid. The outer segment is stated
to contain internally a homogeneous elastic mass, breaking
easily into cross plates, but again, an appearance of cross
striping is explained as due to a regular interruption of a
“color mantel” on the peripheral neurofibrils. The club-shaped
rods differ from the red rod in that the neurofibrils traverse
the whole substance of their outer segments. As to the cone
cells, Schneider says of the neurofibrils in their outer segments :
“Diese Neurofibrillen durften sich im Aussenglied in Windun-
gen legen.” Otherwise the condition of the fibrille is the
same as in the rods.

Greef (:00), who depended chiefly upon osmic acid as a
fixing agent, finds no fibrils. He describes, however, some
details of interest in the structure of the rod, e. g., the
“Zwischenscheibe,”’ a plate between the outer and inner seg-
ment; also the occasional appearance of two “Zwischen-
scheiben” between plates of the outer segment, and a sheath
over the inner and outer segments. Levi (:00) holds much
the same views as Greef as to the structure of the visual cells.

Hesse (:03), in a paper read before the Deutsche Zoolog-
ische Gesellschaft, reports the presence of spiral neurofibrils,
and in a later paper he (:04) gives his results on teleosts,
selachians, amphibians, and reptiles more fully. Hesse
declares for two systems of fibrils, both of which he finds
present in rod and cone cells. The first, which appear in
general as parallel longitudinal lines, he believes to be thicken-
ings of the sheath, confined to the periphery, where they have

No. 3.] VISUAL CELLS INV VERTEBRALIES. 571

a mechanical function. He does not trace them proximally
beyond the external limiting membrane. The second is a
system of parallel spiral fibres running from one end of the
element to the other (including the nucleus) and always lying
near the external surface. These he believes to be neurofibrils,
the conducting elements of these optic organs. The spiral
fibres described by Ritter (’912; ’91b) and Krause (’92) he
mentions as possible records of the same feature. That these
received so little credence (see criticism of Merkel, ’92; Greef,
:00; Ebner, : 02) he thinks is due largely to the unconvincing
appearance of the figures.

Very recently there have appeared publications from Kolmer _
(:04), Held (: 04), and Retzius (: 05), describing an appear-
ance in the visual cells, not to my knowledge reported before,
namely, a single relatively large peripheral fibre passing from
diplosomes in the inner segment and over the whole length
of the outer segment. The demonstration of this fibre was
obtained by the use of silver-impregnation methods. Like
results have been reported by Furst (:04) using hematoxylin
staining on embryonic tissue.

The investigations upon which the present paper, is based
were carried on chiefly in the Zoological laboratories of Har-
vard University at Cambridge, during the years 1902 to 1905.
A part of the work was done in the laboratories of the United
States Fish Commission at Woods Holl, during the summers
of 1902 and 1903.

Before taking up this special problem I made studies under
the direction of Professor William A. Locy, upon the devel-
opment of the Vertebrate retina. In the fall of 1902, at the
suggestion of Dr. G. H. Parker, I took up as a special prob-
lem the more limited field of the structure of the visual cells
in the adult.

In this work I have received very considerable assistance
from several persons, for this I owe especial acknowledgment.
Dr. Parker has given the work his constant supervision and

572 HOWARD. [Vor. XIX.

rendered me every encouragement by helpful suggestions and
valuable criticism.

I am indebted to Dr. E. L. Mark for the excellent oppor-
tunities of the Harvard Zoological laboratories and for help
in the arrangement of plates, as well as kindly interest at all
times.

Thanks are due Professors J. E. Wolff and Charles Palache
for apparatus and assistance in the use of the same; also to
Doctors F. B. Mallory and F. H. Verhoeff for suggestions
in technique.

In addition to these, there are many to whom I am under
obligation for kindly assistance. To these I wish here to
express my thanks.

ii -OBSERVATIONS:

A. GENERAL METHODS AND TECHNIQUE.

I began my study of the visual cells in the frog, Rana
pipiens Shreber, because of the ease with which this animal
can be obtained at all seasons, and because of the large size
of its elements. The importance of the latter consideration
is obvious and led me finally to study the retine of the large
salamander, Necturus maculosus Rafinesque (1819), the
“Mud-puppy” of the St. Lawrence and Mississippi basins.
The rods in this species proved to have a diameter two and
a half times that of the rods:in the frog, and larger than
those of any other vertebrate known to me. This is in keep-
ing with the well known fact that in Necturus, the histologi-
cal elements are unusually large, the red blood corpuscle being
the largest red corpuscle known. As this animal is com-
monly kept by dealers for supply to zodlogical laboratories,
it can be obtained readily before ice appears and kept alive
in laboratory tanks with running or standing water, of a
depth just sufficient to cover it. The size of the visual ele-
ments in Necturus led me to use them in preference to those
of the frog as a basis for my studies.

No. 3.] VISUAL~ CELLS SIN VERTEBRATES: 573

The advantage of size outweighed the two disadvantages
of a small eye and a thick sclera. The small size of the
eye renders manipulation difficult in the removal of the retina,
and limits the amount of available eye fluids for study of the
retina in the fresh condition, while the thickness of the sclera
hinders the penetration of fixing fluids.

Two general methods of study were followed; permanent
preparations were made according to the various devices of
microscopical technique; and fresh material was studied while
in the eye fluids, under as nearly normal conditions as possible.

In the technique of the rods and cones certain peculiarities
of the tissue have to be taken into account. As they are
such unstable and comparatively delicate bodies, special fixing
fluids must be used. The finding of a suitable fluid was a
matter of considerable experimentation, in which the mere
preservation of a natural gross form of the bodies was the
least perplexing part of the problem. It was more difficult
to find a fluid which would permit staining, and still do little
damage to the internal structure of the element. The tests
for these requisites were dependent, in the main, on results
obtained after differential staining, though tests with polarized
light were also employed as a check on fixation. The latter
furnished interesting data, which will be taken up in detail
under observations upon the effects of different fixing fluids.

The difficulty of admitting fixing fluids to the retina with-
out violent mechanical disturbance, is a problem which pre-
sents itself in the technique of small eyes, especially when
they possess a heavy sclera. Immersion of the whole eye
in the fluid does not guarantee immediate fixation, while
cutting open the eye usually causes a wrinkling of the retina,
even if no mechanical injury results. Wrinkling, and buck-
ling of the retina away from the choroid, seems to be due
to different degrees of contraction of the sclera and the retina,
when treated with the fluids.

I found the following method most successful in preventing
such effects, and in preserving the eye in an apparently natural

574 HOWARD. [Vora xi

condition. The animals were anesthetized, their hearts
exposed, and the fixing fluid injected into the arteries as in
ordinary injections for the demonstration of the arterial
system.

Some of the fluids used were aqueous mercuric chloride
containing 5 per cent. acetic acid, Perenyi’s fluid, 11% per cent.
osmic acid and vom Rath’s (’95)_ picro-platino-osmo-acetic
mixture. The first two penetrated most successfully. The
osmic preparations were only partially successful, for, owing
apparently to the rapid constriction of the blood vessels, a
smaller amount of the fluid reached the interior of the eye
than by the other. methods. iter injection, the eyes were
removed and placed in the fixing fluid, or else the whole head
was immersed and the eye not opened until they were thor-
oughly hardened. Eyes thus prepared were imbedded in
melted paraffine and cut for longitudinal or transverse sections
of the rods and cones.

For a satisfactory study of the rods and cones it is usually
necessary to free them from surrounding pigment. This may
be done by bleaching on the slide, or, while the animal is
alive, by keeping it in a dark box for a few hours, or con-
veniently over night, and then fixing the eye without exposure
to the light, I got best results in Necturus by aneesthetizing
with chloretone in the dark box. Chloretone was used to
avoid the irritation and consequent advance of pigment which
ether and chloroform seem to produce. The method described
causes the retinal pigment to withdraw completely from the
region between the rods, into the bodies of the retinal pigment
cells. :

Bleaching can be resorted to conveniently, if there is no
reason for avoiding the necessary chemical treatment. This
is obviously the most practical method of studying the rods
and cones in their “light” phase. It also has the advantage
that the rods and cones are protected, and prevented from
breaking by the slipping of the retina over the pigment layer,
when portions of the eye are removed for sectioning. Bleach-

No. 3.] VISUAL CELLS IN. VERTEBRATES. 575

ing was done on the slide by the potassium chlorate method
(Lee, :05), or by the potassium permanganate and oxalic
acid process (Mallory :05).

In the study of fresh material the cornea and lens were
carefully removed, the eye divided, and the retina placed on
a slide. In this process as much of the eye fluid as possible
was removed with the retina, which was then teased in it
and covered. The fluid at the edge of the coverglass coagulates
and promptly checks further drying from exposure to air.

With such a preparation, a field containing detached rods
can readily be found. These are usually broken, but occa-
sionally a whole element was found intact, as for instance
where a fortunate fold of the retina gives the visual cells in
profile.

When more fluid than could be obtained from a single eye
of Necturus was needed, humor from the eye of a frog or an
artificial examination medium was used.

In tests for suitable media the most satisfactory that was
found was the more fluid portion of white of a hen’s egg.
In the more artificial media that I used, the elements disinteg-
rate very rapidly.

Fresh preparations, put up as described were studied either
under an ordinary microscope or a polarizing ne.

The effects of reagents and stains were determined by
introducing solutions of these (usually very dilute) at the
edge of the cover-glass, while the object was under obser-
vation.

B. PERMANENT PREPARATIONS.

Observations of the visual elements begun on fresh unfixed
material would be a logical introduction to their study, but,
because of the difficulties in manipulation and interpretation,
I found it hardly practicable. One must first gain some
familiarity with the objects from a study of sections or, at
least, from hardened material. On this account I have under-
taken to describe first permanent preparations, selecting those
which gave evidence of best preservation.

576 HOWARD. [Vor. XIX.

IT. Osmic Acid Material.

Osmic acid, or osmium tetroxide, (OsO,) has held probably
as important a place as any fixing reagent in the investigation
of the visual cells (Schultze, 66-72: Hoffmann, ’75; Greef,
7 OO):

I have used osmic acid without admixture of other reagents
chiefly in the form of vapor. Eyes which were not opened
were suspended over a 2 per cent. aqueous solution of osmic
acid in a tightly closed bottle for three minutes. This method
seems to have distinct advantages over the use of this reagent
in fluid form. It avoids the danger of distortion and tearing
of cells by osmotic pressure; as no opening of the eye is
necessary, the danger of disturbance from other mechanical
causes 1s also eliminated. Penetration is very rapid, two
or three minutes’ exposure being sufficient to fix the rods
and cones. <A retina thus fixed may be teased immediately
upon a slide in glycerine, and isolated rods and cones found
in the field of the microscope (Pl. 4, Fig. 33); or the whole
eye, after it has been hardened in alcohol and its lens has been
removed, may be cut into sections and mounted in balsam
(Pl. 4, Fig. 35). Dyes do not readily stain tissues which
have been treated with osmic acid; at least, I have been
unable to get evidence of fine differentiation even after bleach-
ing, and treatment with potassium bichromate as recommended
by Lee (:05). If preparations fixed in this way were more
susceptible to stains, the method would furnish, no doubt,
a most valuable check on other methods of fixation.

In a retina from Necturus fixed as described by osmic acid
fumes, the rods and cones have the following appearance.
The cylindrical outer segments of the rods (Pl. 4, Fig. 33,
prs. dst.) vary in tint from black to a translucent brown,
depending upon the action of the fixing fluid, whether over a
longer or shorter period. The other portions of the rod, as well
as the whole of the cone, show varying shades of light brown
or greenish grey, of much less striking character.

No. 3.] VISUAL CELLS IN VERTEBRATES. 57

Between the outer and inner limbs is the intermediate plate
(“Kittsubstanz,’ Schultze, 67, p. 218; ‘“‘Zwischenscheibe.”
Greef, :00). This is unstained by the osmic acid and appears
as a thin ight band in marked contrast to the black or brown
of the outer limb.

The inner limb shows a differentiation into a distal*
ellipsoid and a proximal paraboloid (Krause). The ellipsoid,
which has either the shape of the segment of a sphere, or is
cylindrical, is distinctly granular. A sheath is not readily
demonstrable in osmic-acid material, but is easily shown by
other methods.

The paraboloid is more transparent than the ellipsoid and
is without evidence of granulation. It has a well defined
inner clear portion and an outer less transparent sheath. Its
form varies from ellipsoidal or paraboloidal to plano concave
or plano convex, with the plane surface always distal. The
flattened and concave conditions are probably distortions due
to fixation. The paraboloid takes a selective purple stain,
different from any other retinal structure, in preparations sub-
jected to the following treatment. Material fixed 3 minutes in
osmic acid vapor is prepared for treatment on the slide in the
usual way: slides are placed in a % per cent. solution of per-
manganate of potash for 20 minutes; then in a I to 5 per cent.
solution of oxalic acid for 30 minutes. After washing, they are
stained for 1 to 24 hours in Boehmer’s hematoxylin. The
excess of stain is removed by 7o per cent. alcohol acidulated
with hydrochloric acid and controlled by alcohol containing
traces of ammonia.

The nuclei (P1.'3, Fig. 20, st. nl. ex.), which in Necturus
lie almost entirely proximal to the membrana _ limitans
externa, are closely packed in a layer one deep in the func-
tional part of the retina, but two deep toward the ora serrata.
It is probable that extra-nuclear plasm from the inner segment
is continued over the sides of the nucleus, but if so, it is

* Proximal and distal are used throughout this paper with reference to
the center of the eye. In the figures on the plates, proximal is above and
distal below, except in detached portions of cells.

578 HOWARD. [Vov. XIX.

so thin as not to be distinguishable from the nuclear membrane.
This condition is evident in sections, but still more apparent
in isolated elements (Pl. 4, Fig. 33). In such cases, ensheath-
ing cytoplasmic material can be seen passing around the
nucleus into the root-like process, the rod foot (Pl. 4, Fig.
33, pd. bac.) with dentritic extensions into the outer reticular
layer.

The cone elements (Fig. 33) are of about the same length
as the rods. The outer segments take a darker color than
the other parts, but not as deep a shade as the rods. The
osmic acid evidently (especially after longer fixation) has
a destructive effect here, as the outer segment of the cone
shows irregular fissures and has a broken appearance. ‘The
other parts, corresponding with those of the rod, agree with
these in color and appearance, indicating similar chemical
behavior as regards osmic acid. However, there are some
differences in form beside those of the conical outer segment ;
thus the ellipsoid is longer and the paraboloid shorter, than the
corresponding parts of the rod.

Cross sections of the outer segments of the rod appear
roughly circular with corrugated outline (Pl. 4, Fig. 36).
At a magnification of 1,450 diameters the dark circle appears
to be bordered usually by a light line, outside of which is
an intensely black corrugated edge, which evidently repre-
sents an enveloping sheath on the outer segment. In longi-
tudinal thin superficial sections of the outer segment striations
can be seen which correspond in number with the corruga-
tions of the cross sections, and demonstrate that the outer
segments of the rod are fluted (Pl. 4, Fig. 35).

At a much higher magnification (3,800 diameters) the
contrast between center and rim is more marked, the latter
being blacker while the white band between the two appears
to be interrupted by radial extensions of the central substance
(Pl. 4, Fig. 34) corresponding with the depressions of the
corrugations. This appearance would indicate that the light
band is not simply the result of the optical effect of the sheath,

No. 3.] VISUAL -CELLESTIN VERTEBRATES, 579

but represents substance unblackened by osmic acid. After
bleaching such material, and staining it with hematoxylin,
I have obtained “in cross sections evidence that the outward
projection of the corrugated outline represents a fiber circular
in cross section and stainable. The central mass included by
these peripheral structures seems quite homogeneous, as in
fresh material.

Frog rods treated by the same methods reveal a dark rim
and a light line, but I have not been able to distinguish in
them the corrugations. Such, however, have been reported
by Hensen (67, Fig. 7) and others.

Besides the ribbing of the surface and the underlying light
spaces of the outer segments, I have seen no direct evidence
of fibrillation in osmic material. That osmic acid fixation
is in some ways very unfavorable for the demonstration of fine
structural details, there can be no doubt. I have found no
after-treatment by way of bleaching, etc., which satisfactorily
restores the susceptibility to selective staining in the finer
details. In other respects osmic fumes preserve very suc-
cessfully the gross appearance of the fresh elements, in their
almost optically homogeneous state. Whatever differentiation
there is in the latter, is faithfully preserved in delicately fixed
material.

2. Vom Rath Material.

Vom Rath’s picro-platino-osmo-acetic mixture, often used
in the study of finer details of nerve cells, gives good preser-
vation for the nuclear portions of the visual cells, but not
for the distal parts. The outer segment of the rods becomes
an opaque black, and as a rule contracts to one-half its normal
length. The outer segment of the cones becomes much
broken. In certain cases the longitudinal striation of the
outer segment of the rods is plainly brought out (Pl. 4,
Fig. 32, prs. dst.). Cross sections seem to indicate that the
peripheral lines are not always confined to the periphery, but
extend as clefts into the central mass (PI. 5, Fig. 40, bac.)

580 HOWARD. [VoL. XIX.

That these are clefts and due to the effect of the reagents,
is indicated by the inequality of their depth and their absence
in the osmic-acid fixation. The outer segments of the cones
are as a rule poorly preserved, but show a cross striation
with a tendency to an arrangement of the bands in pairs.

3. Corrosive-Acetic Material.

After trying a solution of mercuric chloride with different
proportions of acetic acid, the best results were obtained from
a saturated aqueous solution of mercuric chloride containing
5 per cent. of glacial acetic acid. The fluid was injected
into the blood vessels, as already described, and the eye was
immersed in the fluid for from 24 to 48 hours. I believe a
short fixation with this fluid is not in general sufficient, not-
withstanding theoretical considerations (Mann, :02). I have
arrived at this conclusion empirically from the results of
experiments by others, as well as by those I have made myself.

After the sections were cut they were stained on the slide
by either the iron-alum-hematoxylin process of Heidenhain
or by Mallory’s (: 00) triple stain. In the-former case long
staining of 40 hours in old hematoxylin was followed by
decolorization so as to give on the same slide as great a
range as possible between a strong stain and complete decolor-
ization. Extremes are shown in Figures 1 (Pl. 1), 20, and

2a nC ies),

i Ne CUS:

Rod Cells—The outer segments of the rod retain a slight
stain, mostly in the form of reticulations apparently due to
a very fine net-work. This is accentuated into stronger lines
by a condensation due to the formation of vacuoles (Pl. 1,
Fig. 1; Pl. 3, Fig. 20). In well preserved rods longitudinal
striations are visible at upper and lower focus and usually
more apparent in the latter (Pl.-1, Fig. 15 Pl:2; Fies. 7, a:

No. 3.] VISUAL CELES IN VERTEBRATES. 581

Pl. 3, Fig. 20). These lines have a parallel trend and ten to
fourteen of them may be counted on one side of a rod. In
cross sections of the outer segments (Pl. 2, Fig. 9) well defined
circular dots are present in the periphery of the section. These
correspond in number with the striations seen in lateral views,
which, with other evidence, determines their character as
definite fibers.

In most cross sections of the outer segment there are, just
within the circumference, vesicles of somewhat regular
arrangement but varying in size (Pl. 2, Fig. 9, vac). After
fixation by mercuric chloride there is no differentiation of a
definite sheath such as is seen in osmic acid preparations.

Now and then outer segments occur showing dark transverse
lines at regular intervals, as well as dark plates separated
by light lines. Fig. 24 (Pl. 3) is a drawing of such a rod.
This was a detached outer segment and possibly had progressed
more rapidly than the attached rods in the changes which
bring about the plate-like cleavage of the outer segments.

The intermediate plate appears in this material as a very
narrow light zone between the outer segment and the ellip-
soid. It does not take the stain and seems more refractive
than other portions (Pl. 1, Fig. 1, dsc. im.). The fibers,
already described, pass over it to the ellipsoid.

The ellipsoid contains considerable stainable substance,
being strongly stained by eosin, fuchsin, hematoxylin, ete.
Where hematoxylin is used, the mass of the ellipsoid may be
a homogeneous black, or this may be resolved into globules
(Pl. 1, Fig. 1, ell. bac.; Pl. 3, Fig. 20). When the ellipsoid
has been decolorized sufficiently to become translucent, super-
ficial striations can be made out (Pl. 1, Figs. 1 and 6; Pl. 2,
Fig. 7). In cross sections (Pl. 1, Fig. 6) these can be identi-
fied as fibrils, which have retained the stain and are undoubt-
edly continuations of those described for the outer segments.
The ellipsoid body appears in some cases to be enclosed on all
sides (Pl. 3, Fig. 20; Pl. 4, Fig. 33) by the light staining
sheath substance. In most cases, however, a separation can

582 HOWARD. [ Vou. XIX.

scarcely be distinguished distally between it and the intermedi-
ate plate and proximally between it and the paraboloid (PI. 1,
Pic. 1; Pl. 2, Figs. 7,78). lprseems ‘probable, owever,.wemdr
there is in all cases a separation and that the ellipsoid is a dis-
tinct body entirely enclosed.

The paraboloid in this material often has an ellipsoidal form
(normal), but is almost as frequently flattened by pressure.
This seems to be due to a forcible contraction in fixation, of
the “rod myoid,” a name given by Greef (:00) to the con-
tractile part of the inner segments of the rods and cones.
In Necturus this myoid ts often little more than a sheath to the
paraboloid. As the ellipsoid and nucleus are hardened more
quickly than the paraboloid, the latter is moulded to them.

The substance of the paraboloid is chemically unlike that
of the ellipsoid, since most stains affect it but little. A close
study of material stained in hematoxylin reveals a very close
reticulume (Ply 1, Pigs. 1, 4, 7a10:0Ge. Fl oiic. 20) omtaae
same material stained with Mallory’s (:00) triple stain gives
a coarser meshwork of a blue staining substance having nodal
dots (Pl 2 hic 8) pa bebac.):

In the periphery fibers are demonstrable in both lateral and
sectional views, as in the parts of the rod previously described.
Here, however, a clearly defined sheath of considerable thick-
ness is present (the myoid described above), and in this the
fibrils are deeply imbedded. Lying close to the paraboloid
the fibrils (Pl. 1, Fig. 4, B. fbrl.) pass over the surface of the
nucleus, as can be seen by cross sections of the latter at the
distal end (Pl. 1, Fig. 5, B., fbri.) or in lateral view of the
nuclei in radial sections of the retina (Pl. 2, Figs. 7, 8, fbrl.).
I have not succeeded in demonstrating with certainty fibrils
in cross sections of nuclei, where the latter are closely packed.

Proximal to the nucleus the fibrils are sometimes convergent
to the foot process and then divergent (Pl. 2, Fig. 8) ; in other
cases there is no convergence (Pl. 2, Fig. 7, fbrl.), but the
fibrils spread from the end of the nucleus directly out into
the reticular layer.

No. 3.] VISUAL '‘CELES, IN: VERTEBRATES. 583

The nuclei of the rods as well as of the other visual cells
are larger than the other retinal nuclei and are character-
istically elongated in a direction radial to the eye. Their
chromation is either in the form of rather coarse or finer
granules. The character of the nuclei no doubt changes at
different stages of the metabolism of the cell; thus, for exam-
ple, I have seen some evidence in experiments made by Mr. A.
Forbes, that the distribution of chromatin varies with the
degree of stimulation from light. I have seen nuclear division
in embryonic material only. Such probably occurs in func-
tional eyes of larvee at the ora serrata but never in the fundus
of the adult retina. Nucleoli have often been observed with
appropriate stains (Pl. 2, Fig. 7, mll.).

Cone Cells —The outer segments of the cones in Necturus
are extremely unstable. In some respects corrosive-acetic fix-
ation is as favorable as any other for them; but while this
preserves the rods uniformly, the outer segments of the cones
give evidence of considerable distortion. The conical fort
of these elements is quite constant, but they vary in length in
consequence of varying degrees of contraction. The tip is
often curled (Pl. 3, Figs. 20, 21), sometimes spirally. Exter-
nal parallel fibrils are present as in the rod (Pl. 3, Figs. 21,
(ane igor, (prs. dst Pl 1,Mis. 25-Pl. 5, Figsao) These
are usually parallel to the long axis of the cone, but occasion-
ally they have an oblique course, as is evident in Figure 23
(Pl. 3.). Here fine oblique superficial fibrils are to be seen
at the distal end of the outer limb. In Figure 1 the cone
shows the same condition both on the inner segment and over
the paraboloid.

A central portion, which stains dark with Heidenhain’s iron-
alum hematoxylin, is generally present in the outer limb; it
is of varying length, but as a rule it falls short of either end.
Though it stains heavily, the dye is easily washed out in the
mordant. This portion in certain cases shows a plate-like
structure (Pl. 3, Figs. 21, 23). In these instances a spiral is
suggested, but the appearance might be explained as due te

584 HOWARD. [VoL. XIX.

the irregular separation of plates by vacuoles. Three of the
latter are shown in Figure 21 (PI. 3) two on the left and
one on the right. Sometimes the spiral appearance is much
more striking, as if there were two fibers closely parallel,
and suggests some of Hesse’s ( :04) figures. A common
appearance presented by the outer segment of the cone is
shown in Figure 20 (Pl. 3); here the tip only is dark and the
proximal portion is marked by irregular lines, probably cleav-
age effects.

I have observed with certainty no intermediate plate in the
cones of Necturus.

The ellipsoid of the cone differs from that of the rod in
form, being of greater length and smaller diameter. The
stain is retained longer and the resolution of the staining mass
into globules is more apparent than in the rods (Pl. 1, Figs.
1, O50E1 3), Fie, 21 -eP ls, Fis. 30 seran. ella):

The paraboloid is smaller than in the rod and more con-
stantly ellipsoid or ovoid. ‘The sheath is relatively thicker and
fibrils are more easily seen than in the rods. In cross sections
the fibrils appear in two layers, an inner and an outer (PI. 1,
Fig. 44). No evidence of “difference in these ‘circles on
fibrils could be detected with certainty.

The myoid, or contractile portion, between the nucleus and
paraboloid is more distinct here than in the rods. The course
of the fibrils over the nucleus corresponds to that in the rods.
The nuclei themselves are commonly more pointed at the distal
end than those of the rod are.

Double Cones.—As in other amphibians and in the other
vertebrate groups except the mammals, there are in Necturus
the remarkable elements called double cones. In fishes, so
far as I have observed, the two cones of any pair are nearly
alike, but in Rana and in Necturus they are in some respects
quite different. The longer one (PI. 1, Fig. 2, 4) for con-
venience may be called the far cone (con. dst.) and the other
(Fig. 2, B), which for the most part lies nearer the mem-
brana limitans externa, the near cone (con. prx.). These are

No. 3.] VISUAL CELES IN. VERTEBRATES. 585

designated by German authors as Haupt-Zapfen and Neben-
Zapfen respectively. The elements are united to each other
along one side from the region of the membrana limitans
externa to their ellipsoids.

I have been unable to distinguish any difference between
the outer segments of the double cones and those of single
ones.

As the ellipsoids of the pair do not stain alike, they differ
chemically and this suggests a functional difference. That
they are morphologically equivalent, or homologous, no one
would question. In the far cone the ellipsoid takes the same
color as it does in the single cone. That of the near cone
shows much less affinity for stains, in this respect resembling
thereliipsoid: of the rod) (Pl.1, Fig. 2;/ Plas; Pigs 338).

The paraboloids display the most conspicuous difference
seen between the cell organs of the pair. That of the far
cone is slightly smaller than the ellipsoid while the paraboloid
of the near cone is three to four times as large as its own
ellipsoid and looks like a large flask-shaped vesicle.

The myoid*of the far cone. (Pl. 1, Fig. 2, mys com. dst)
is very long, and reaches from the nucleus to the ellipsoid.
In the myoid dark staining fibrils can be seen more plainly
than in any other element. At the distal end, the fibrils pass
around the paraboloid. Their farther course seems to be
the same as in the single cones, where they have their origin
on the outer limb. Seen in optical section the fibrils seem
to end on the paraboloid in small bead-like enlargements,
but by focussing, these are apparently resolved into a con-
tinuation of the fibrils (Pl. 1, Fig. 2, cp.). This appearance
may be due to the fact that these fibrils are more distinct
in cross section than when seen !engthwise. At the proximal
end of the myoid the fibrils pass over the appropriate nucleus,
as described for the other elements, and into the outer reticular
layer.

The fibrils of the near cone lie embedded in the sheath of
the large paraboloid, but otherwise their course is like the

586 HOWARD. [VoL. XIX.

course of those of the far cone. These relations are made
clear in cross sections (Pl. 1, Fig. 5, 4.) and different lateral
views (Fig. 2, 4 and B.). In the preparation represented
in Figure 2, B, the near cone, being out of focus, is shown
by dotted outlines only.

The twin cones possess two nuclei, each element having
its own, though the two lie in close contact. The nucleus of
the far cone is like the other nuclei, but that of the near
cone has a prolongation (Pl. 1, Fig. 2, prc. nl.), which
reaches beyond the membrana limitans externa into the sheath
of the paraboloid. Another difference between the two nuclei
is usually discernible; the nucleus of the near cone (nl. con.
prx.) contains a fine granulation giving a greyish cast, that
of the far cone possesses larger, densely staining granules and
is otherwise more transparent, because of the absence of the
finer granulation.

A well defined foot in the double cone is sometimes dis-
tinguishable (Pl. 2, Fig. 7, pd. con.), the fibrils converging
and then diverging into the middle of the outer retinular layer.

From estimates based on the fundus of the retina, the
relative number of rods, cones, and double cones in Necturus
are: rods, 4; cones, 1; double-cones, 1.

A comparison of double-cones with the other elements, when
stained by Mallory’s (:00) triple stain, brings out some
interesting differentiations in corrosive-acetic material (Pl. 5,
Fig. 38). The ellipsoids of the single cones take on a
brilliant purplish-pink color, while the outer segments take
a lighter but equally brilliant pink, with the exception of the
fibrils, which are blue (Fig. 40). The rods also show the
fuchsin-staining substance, but to a smaller degree, in both
ellipsoids and outer segments. In the latter it is somewhat
irregular in distribution, as if extending in the natural state
throughout the segment, but confined in fixed preparations by
condensation or contraction to its central portions. In the
rods, the prevalence of a blue-staining reticulum masks the
pink somewhat. The mixture of blue and pink in the ellip-

i

No. 3.] VISUAL CELLS IN VERTEBRATES. 587

soids gives a purple effect. A glance at the double cones
shows that this purple stain, characteristic of the ellipsoid
in the rod, is also to be found in the ellipsoid of the near
cone; while in the far cone the stain is like that of the single
cones.

Il. THE FROG.

Preparations of frog retina fixed by corrosive-acetic present
a feature which I have not seen in Necturus when prepared
by the same method. This is a central core (med.) in the
outer segments of the rods (Pl. 4, Figs. 29, 30, 31) of both
the long red rods and the short green rods. This core
measures one-third to one-fourth the diameter of the whole
rod. It takes none of the stains which I have tried, with
possibly the exception of picric acid.

The rods otherwise seem to show the same general features
as in Necturus. The intermediate plate, ellipsoid, and parab-
oloid show the same reactions to stains. The paraboloid
in the frog is not as easily distinguished as in Necturus and
has not usually been noticed by observers, but I believe it has
been simply overlooked on account of its small size.

The fibrils I have not studied in this material, but, in rods
of the frog preserved in Perenyi’s fluid I have distinguished
superficial longitudinal fibrils (Pl. 4, Fig. 27, fbri.). The
presence of visual-cell nuclei in a double layer, as contrasted
with the single layer of Necturus, is a difference to be noted:
also the presence of “green rods’ and “cone color globules,”
which [ have not observed in Necturus.

Ill. THE GOLDFISH.

In the goldfish (Carassius auratus) we find an outer nuclear
layer of four or five strata of nuclei (Pl. 3, Fig. 19). There
are present single cones, double cones, and rods; these are
of the type of the “green rod” in frogs with long inner

588 HOWARD. [Vov. XIX.

segment. The rods (which may possibly be of two types)
are extremely small in diameter and the staining effects so
varied that I can not put much reliance on the appearances as
an index of minute structure. Cross sections of the rods give
evidence of a central core unstained by hzematoxylin as in the
frog.

The case of the large double cones is different. Here, in
well preserved specimens, a constant appearance is presented
of a system of peripheral spirals (PI. 3, Fig. 18, prs. dst.)
made up of four or five fibrils. On the inner limb, proximal
to the ellipsoid, straight fibrils can be traced to, and over
the nuclei. Their number does not correspond with that of
the spiral fibrils. The nuclei of the double cones lie close
together and each has a distinct cone foot.

C. FresH MATERIAL.
In Ordinary Light.

A thorough familiarity with elements in their normal liv-
ing condition, or as near as possible to this state, is of the
greatest importance in histology. This is especially true of
investigations into the nature of the optical properties of
living bodies, since the process of fixing or “‘killing’’ is so
liable to affect these properties. Though gross form and
structure may not be as sensitive to chemical alterations as
molecular structure, yet even here, as is well known, fixation
may do the greatest violence. As a check upon such effects,
a knowledge of fresh material is indispensable.

(a) RODS.

The Outer Segments of the rods may be quite easily obtained
by the method already described (pp. 574, 575), and a fortun-
ate preparation may give complete rods and cones im situ.
In Necturus, however, the cones, on account of their insta-
bility, are not easily found in teased fresh material.

Se ee

No. 3.] VISUAL CEELS IN VERTEBRATES. 589

The outer segments of the rods in Necturus are cylindrical,
transparent, highly refractive bodies, measuring on the aver-
age I2 micra in diameter by 36-40 micra in length. The
distal end is rounded, but not enough to make the end hemi-
spherical (a form usually assumed in fixed material).

The most conspicuous finer details or markings in outer
segments just removed from the eye, are visible under a mag-
nification of 1,000 diameters at a low focus, but not at the
lowest (PI. 2, Fig. 13). These are slightly oblique length-
wise striations. They appear as dark lines with a lighter
ground substance between them, and usually about eight to
ten such lines are visible at once, evidently in focus on, cr
very close to, the lower surface. On the upper surface,
usually, only a single line or possibly two or three are visible
at one time (Pl. 2, Fig. 12). The difference is probably
due to the optical effect of the cylinder converging the rays
from the lower curved surface, so as to make them visible in
one plane, thus bringing them into the same focus. At a
focus about the lowest at which anything is visible, the dark
lines appear bright, while the substance of the rod is dark
(Pl. 2, Fig. 14). These lines evidently represent less refrac-
tive material separated by a more refractive substance.

The outer segments, soon after the preparation is made,
show a slight bulging of the detached proximal end, later
this is more pronounced, and lines of transverse cleavage
become visible (PI. 2, Fig. 15). The rod shown in Figure
15 had been under a cover-glass three hours. In this case
the longitudinal lines were plainly visible from the upper
surface. The lines were not noticeably spiral in this instance
and illustrate an individual variation in this respect. In this
rod (PI. 2, Fig. 16) distinct plates could be seen separated
from each other by small spaces. Occasional individuals in
a field of detached outer segments, perfectly fresh, show
dark transverse zones or bands, usually only one to three in
a rod, as if some of the disks were darker than others.
Transverse cleavage as thus described is not always found;

500 HOWARD. [Von. XIX.

in fact, regularity in the breaking is very frequently not
obvious.

In addition to the superficial striations visible during one
to three hours after the removal of the rods from the eye,
a central core is discernible; this is sometimes of slightly
different color or shade from the rest, is regular in outline,
and from one-fourth to one-third the diameter of the rod.
It is very frequently seen at middle focus. If this appearance
were the only evidence for the existence of such an internal
structure, I should, on account of its inconstancy, look for its
explanation in simple optical effects as many others have
done. But additional evidence has been found in fresh mate-
rial in the form of an occasional projection of a central
portion beyond the broken proximal end of the outer seg-
ment. In one such case (Pl. 5, Fig. 42, med.) this axis took
a differential stain in toluidin blue (see pp. 604, 605). .

To aid in an interpretation of the appearance of the outer
segments as seen lengthwise in the fresh condition, it is of
advantage to have them in optical cross-section. This can
be done by placing a fresh retina, proximal surface down,
on a slide and employing a support for the cover-giass.
The outer segments thus viewed (Pl. 2, Fig. 17) are. gen-
erally circular, but frequently with considerable variation from
a true circle. The outline appears crenate and in some
instances nothing more is discernible. In others a distinct
border can be made out, and this border in favorable light
is distinctly resolved into small circles of highly refractive
substance. It is evident, then, that these circles represent the
highly refractive portions between the dark lines and are fibrils
(Pl. 2, Fig. 13). The portion between the fibrils, of smaller
diameter and less refractive, appears as dark lines when in
focus (Pl. 2, Fig. 13) and as light lines on lower focus (PI. 2,
Bigs).

On first inspection one would think the dark lines of Figure
13 (Pl. 2) were identical with the staining fibril of Figure 1
(Pl. 1) because of relative sizes, but this seems not to be the

No. 3.] VISUAL CELES* IN- VERTEBRATES: 501

case, so far as can be judged from all the evidence obtainable.
Cross sections from osmic material appear very much the same
as the optical sections of fresh rods. There is no reason to
doubt that the small refractive circles which in both cases
produce the crenation are identical.

When the cross sections of osmic material are stained,
after bleaching, a fibril is differentiated corresponding in
position with the small circles or the ridges in the crenate
outline and not to the grooves of this outline. The slight
difference in size between the fibrils as seen in the fresh
condition and when stained can be explained as due to the
fact that a sharply outlined, stained fibril appears smaller
than an unstained one, whose optical differentiation from the
surrounding substance depends simply on a different index
of refraction. Of course it is possible that the stained fibril
might represent only the center of the small circles, analogous
to the axis cylinder in the center of a medullated nerve. The -
minuteness of the objects, however, forbids the certain deter-
mination of this point with any apparatus one can command
at present.

The intermediate plate in the fresh condition, when discern-
ible, appears as a disk at the proximal end of the outer seg-
ment. It is apparently of a different refractive index from
the latter, or at least is more transparent.

The ellipsoid usually has the form of a convex-concave
segment ofa cylinder lying within the substance of the inner
limb; its diameter is only slightly less than the limb itself.
The convex surface is distal. In the fresh condition the
ellipsoid is more flexible than the paraboloid. From the con-
dition presented by the fixed visual cells, however, the reverse
would appear to be true. The probable explanation of this
apparent contradiction is that the reagents used harden the
ellipsoid more quickly than the paraboloid, the latter remaining
for a longer time comparatively plastic. Immediately after
death the ellipsoid is comparatively clear and highly refrac-
tive, perhaps possessing the latter characteristic to a greater

592 HOWARD. [Vou. XIX.

degree than the outer segment. In a brief time granulation
sets in, followed, as soon as the ensheathing substance of the
outer segment is broken, by complete dissolution. The degree
of instability of the ellipsoid is next to that of the outer
segments of the cone.

The paraboloid in the fresh rod of Necturus has, as its
name appropriately signifies, a paraboloid form. As a rule
its diameter is less than that of the ellipsoid, while the total
diameter of the inner limb remains the same. From this
fact it is seen that the ensheathing substance is thicker than
that about the ellipsoid. This contractile sheath corresponds
to the myoid, and the latter term is preferable to the word
sheath, since the paraboloid is a separate body possibly
possessing an independent sheath of its own. Contraction of
the myoid undoubtedly flattens the paraboloid. <A flattened
condition is shown in Figures 10 and 11 (Pl. 2). The para-
boloid has a lower degree of refraction than the ellipsoid,
but greater than the ensheathing myoid. The paraboloid
may be isolated, and when thus separated from its normal
surrounding structures and suspeiided in the eye fluid, it
assumes a spherical form. Here there is no granulation
and clouding, such as we get so quickly in most protoplasmic
substance after death. The appearance suggests the oil
globules of the retinal elements in some amphibians and
sauropsidans, but this resemblance is evidently only
superficial.

The nucleus in the rod is often in contact at is distal end
with the paraboloid. Its distal surface under these circum-
stances is concave, thus conforming to the convex surface of
the paraboloid. Except for this occasional slight depression,
the nucleus has an approximately ovoid form. A cytoplasmic
sheath can be quite readily detected about the distal portion
of the nucleus. I have not been able to distinguish it at the
proximal end in fresh rods and cones. Granulation very
rapidly sets in here, as is the case with most nuclei (PI. 2,.
Figs. 10, 14) mise

No. 3.] VISUAL CELLS IN VERTEBRATES. 593

(b) CONEs.

The outer segments of the cones in Necturus are very
difficult to observe in the fresh state, because of their dis-
tortion and dissolution immediately after death. Individual
cases, however, may sometimes be found which preserve a
constant form long enough to permit of observation and
even of drawing with a camera lucida (Pl. 2 ioe 0) ee laa
Necturus the marked conical form of the outer limb and differ-
ences in the ellipsoid make them readily distinguishable
from the rods. The dissolution, so far as there is any reg-
ularity in it, usually results in an elongation of the cone (PI. 3,
Fig. 22) combined sometimes with a spiral twist. While still
intact the appearance of the cone is like that of the outer seg-
ment of a rod, but less refractive. I have not observed an
intermediate plate in the case of the cones.

The other portions of the cone appear like the corresponding
parts of the rod, except that the ellipsoid of the cone is longer
and the paraboloid is usually not in contact with the nucleus.
Figures 1 (Pl...) and 20 (PI. 3) give a fairer idea of the
usual form than the fresh cone shown in Figure, 10, (Pl o2)y,
as the latter is abnormal.

2, In Polarized Light.

During my studies on fresh material the question arose,
whether there were not some means of making visible in the
fresh elements structures which the inspection of fixed prep-
arations led me to believe to be present in the living rod.
Such a method, if found, must be in the nature of a variation
in the light used. Polarized light seemed to offer the method
desired, since, as is well known, some transparent bodies of
similar appearance in ordinary light are brought out in strong
contrast when seen under a polarizing microscope. Again,
organic bodies of a fibrous structure give a definite reaction
by this method and the direction of the fibrils seems to deter-
mine the result, since the color reaction is constant for a given
direction.

504 HOWARD. [Vor. XIX.

Outer rod segments were first examined in a_ polarizing
microscope with polarizer and analyzer alone. In this way
no evidence of double refraction by extinction was found.
However, certain features were brought out more plainly than
with ordinary light, viz., the axial core and transverse banding.
The visibility of the latter seems to depend upon the direction
of the illumination with respect to the rod itself. The desired
angle can be obtained for any given rod by turning the revolv-
ing stage of the microscope.

\Vhen a gypsum interference plate is introduced between the
analyzer and polarizer (or Nicol prisms), and the prisms so
placed as to give a sensitive red of the first order, the outer
segments of the rod give a definite reaction. In a teased
preparation of fresh retina a field may easily be found contain-
ing detached rods lying in various directions. Outer seg-
ments lying parallel to the a axis, or negative optical direction
of the gypsum plate, were bright yellow while those at right
angles to this were bright blue. The colors of an individual
rod may be reversed by turning the preparation so as to bring
the long axis of the rod into a line at right angles to its
former position. (Pl. 5, Fig. 43.) The bright yellow. or
blue of the outer segments appears in marked contrast with
the inner segments which retain the general red field color.

These observations were made on the rods of Necturus, but
I have also tested the outer segments of rods in the frog,
hen, guinea pig, mouse, rat, and ox, as well as in the outer
segments of the cone-like elements of the turtle and snake,
and I have obtained in all cases the same result. In the rods
and cones of the goldfish I obtained no reaction, although the
outer segments are fully as large as some which gave distinctly
positive results. The smooth dogfish, Mustelus canis, gave
results similar to those from Necturus.

The definite reaction obtained in the forms mentioned
demonstrates that the outer segments (at least in their pre-
dominating substance) are doubly refractive or anisotropic,
with the long axis in the positive optical direction; 1. ¢., as

No. 3.] FISUAL, CEELS’ IN VERTEBRATES: 505

regards their optical properties, they have axes of maximum
elasticity at right angles to their lengths. As the red of the
held color is lowered to a yellow when rod segments lie
parallel to the a axis of the gypsum plate, it determines the
long axis of the rod as optically the (c axis) positive direction.

To obtain an immediate basis of comparison, similar tests
were made on other organic tissues which seemed, or were
known, to be of a fibrous structure. Thus naked axis cylin-
ders from the inner surface of the ox retina gave light reac-
tions like those of the outer segments. The same was true
of striped muscle fibers from the crayfish, frog.and ox, con-
nective-tissue fiber from the ligamentum nuche, vegetable
fibers, longitudinal and radial fibers in hard wood, and central
fibers of Spanish moss, etc. The rhabdomes from the com-
pound eyes of crayfishes showed in general the long axis as
the negative optical direction, but when it is remembered that
the fibrous structure of these bodies is at right angles to their
length instead of being parallel to it, it will be seen that they
agree with the preceding examples in their optical reactions.

In the slug Limax maximus the distal portion of the visual
cell, which corresponds with the outer segment in vertebrates,
displays somewhat complex reactions. In Figure 46 (Pl. 5)
I have indicated the character of these reactions as made out
in a fresh preparation. In a diagrammatic way I have also
shown .the fibril relations, as figured by Dr. Grant Smith (: 06)
from fixed preparations. It will be seen from the diagram
that the character of the reaction depends on the direction
of the neurofibrils. Where the latter are parallel to the a
axis of the gypsum plate the field color is lowered to a yellow,
and where the fibrils are at right angles to this axis the field
color is raised to a blue. Portions of the body in which the
fibrils would be seen on end are neutral and so do not affect
the reaction of fibrils in the plane perpendicular to the direc-
tion of the transmitted light ray.

From the above observations on fibrillar bodies, and
especially on those that are nervous structures in which fibrils

506 HOWARD. [Vou. XIX.

have been demonstrated, the deduction would be natural, that
the outer segments of rods are bodies possessing, not a trans-
verse, but a longitudinal structure comparable to that of the
axis cylinder of a single nerve fiber, in which the substance is
differentiated for longitudinal conduction.

The question might arise as to whether polarization here
were due to certain qualities inherent in individual fibers or
whether it were due simply to the gross grouping together of
fibers. It seems probable that the former is true and that
a certain arrangement of substance, perhaps molecular and
characteristic of organic fibers, accounts for the effect on light.
A case of double refraction in a glass rod may help to
illustrate the point. Such a rod ordinarily will not show
double refraction; 7. e., the glass is isotropic, but if the rod be
subjected to a stress (pressure or tension) the glass will cause
polarization of light which passes through it. In the one case
the rod (or fiber) is not doubly refractive, in the other the
particles of glass are so disposed by the stress that they effect
the light differently from what they did before. Tension in
the direction of the axis will have the effect of determining
the axis of maximum elasticity as transverse; while pressure
in the longitudinal direction will change that (optical) axis
to longitudinal. The mere cylindrical form of the glass rod
will not produce polarization nor will polarization occur when
several isotropic glass rods or fibers are placed together; the
phenomenon depends upon a condition of the particles of glass
in individual rods or fibers.

The view (based on comparison of reactions with fibrous
bodies) that the outer segment of the visual rod is longi-
tudinally fibrous may be opposed by another hypothesis, which
is in accord with many observed facts. This view is, that
the outer segments of the rods are made up of transverse
plates of medullary substance and that between these plates
are transverse neurofibrils which connect with longitudinal
fibrils on the periphery of the rod. This hypothesis is sug-
gested by a marked similarity in appearance, under polarized

No. 3.] VISUAL GELLS “INVERTEBRATES. 507

light, between the rods and the sheath of a medullated nerve
(Pl. 5, Figs. 43, 44). When seen in optical section the sheath
reaction is opposite in character to that of the axis cylinder,
being yellow when that is blue and vice versa. It will be seen
from the figure (Pl. 5, Fig. 44) that the sheath substance is
neutral where the light comes from a direction at right
angles to a surface tangent. Thus a single nerve fiber with
its highly refracting medullary sheath appears most conspic-
uously as two bright yellow or blue (depending on the angle
of the microscope stage) parallel lines with a faintly colored
axis cylinder between. The faintness of color in the latter
is probably due to the predominance of the sheath reaction.

The rod outer segments are chemically similar to the
medullary sheath according to researches of Kuhne (see
Schwalbe, 87, p. 104). The evidences for this are from
such micro-chemical tests as the blackening with osmic acid,
etc. If the rod were made up of plates of medullary substance
with transverse nerve fibrils between, the relation of medullary
substance would be as in the nerve trunks. These fine trans-
verse nerve fibrils of the rod would not affect the light reac-
tion perceptibly (in polarized light) unless in quantity great
in proportion to the total mass of the rod. The longitudinal
superficial fibrils of the rod are probably not sufficient by them-
selves to account for the very distinct anisotropic reaction of
the rod, because their mass is much less than that of the
comparatively faint axis cylinders of nerves. The quality of
the rod reaction in its brilliancy is more like that of the medul-
lary sheath.

The outer segments of the cones in Necturus show aniso-
tropism, but not to so pronounced a dergee as in the rods.
Outer segments from an animal kept in ordinary daylight
and examined while in situ and in good condition gave the
same reaction as rods; 1. e., positive with respect to the long
axis. Cones from an animal kept in total darkness three days
gave the long axis as the negative optical direction. This
reaction is complicated in some way, for when the outer seg-

508 HOWARD. [Vou. XIX.

ments of the cone are at an angle of 45 degrees to the blue
or yellow phase, in the upper field of the microscope, the
half of the cone on the side of the yellow phase is blue and
vice versa. By the theory that the reaction depends on the
direction of the fibrils this would be accounted for by sup-
posing that the cone was composed of fibrils whose direction
was slightly ascending and oblique like the branches of a
conical tree. In the yellow or blue position the fibrils on
each side of the axis (or tree trunk) would not diverge
enough from this axis to be at right angles to it and thus
to give the same color to the whole, but between this posi-
tion and that of parallelism with the axis there would be
one where the color reactions would be opposite on the two
sides of the axis.

This difference between cones exposed and unexposed to
light is possibly due to a difference in tension between the
elongated and contracted conditions. If different sets of
fibrils are present one may be tense while another is relaxed.
However, since such fibers have *not as yet been seen and
our knowledge of the outer segments of the cone is very
limited, such considerations can be only speculative.

D. EFFECTS OF REAGENTS.

Early in this investigation I studied the effects of various
fluids on the visual cells, particularly on the outer segments
of rods, in order to obtain (1) neutral media in which
intra-vitam stains could be used or other tests could be made;
(2) suitable reagents for fixing and permanent preservation;
and (3) means discovering the optical and other physical as
well as chemical properties of these bodies. In judging of
the state of preservation I compared the preserved material
with living material in respect to its reactions to polarized
light, its transparency, the form and behavior of its parts,
and its subsequent staining, etc.

The use of polarized light as a basis of comparison seemed
eminently suitable, for, assuming that minute structural con-

EE

No. 3.] VISUAL CHELS \IN* VERTEBRALES: 500

ditions determine the light reaction, it follows that if a fluid
were found which preserved the same reaction as that of the
fresh rod, one might infer that little violence had been done to
that particular structural condition. Subsequent experiments
showed that perhaps the test was too delicate for practical
application to fixing fluids, since none were found which ful-
filled that requirement. However, although none were found
which preserved the reaction of normal rods, yet the rate of
change and character of the final result furnished some index
as to the relative merits of the fluids.

1. Examination Media.

For examination media the normal eye fluids would natur-
ally be expected to be the best. In Necturus, however, the
small volume of the fluid obtainable from an eye presents
practical difficulties, there being scarcely enough in one eye
after the necessary manipulation, to fill out one cover-glass.
The eye fluids from the frog can be used for Necturus and
make a satisfactory substitute. That the substitute is not
perfect, however, is to be seen in the fact that the frog rods
transferred with the fluid show better preservation after a
given period, than do those of Necturus. Outer segments
of rods of both species after twenty-four hours show in
polarized light normal (positive) reactions but reduced bril-
liancy.

Glycerine (concentrated). Outer segments in one hour or
less become granular and disintegrate somewhat, at the same
time bending into horseshoe. shapes. After seven days the
reaction to polarized light is normal except for reduced bril-
liancy. The reaction of ligamentum nuchz was normal even
after it had been two years in glycerine.

Glycerme, 1 vol.; Water, 2 vols.; Alcohol, r vol. This
mixture gave better preservation than glycerine and water
alone, or concentrated glycerine, or in fact than any other
purely artificial mixture tried. The reason for this, I suppose,

600 HOWARD. [Vor. XIX.

was that the fluid was probably isotonic with the cell
fluids. When this solution was introduced at the edge of the
cover-glass a remarkable reaction of the outer segments of
the rods was observed. An individual rod was watched under
an eye-piece micrometer, and the following changes in dimen-
sions noted. Before admission of fluid the length of the rod
was 6 divisions; at entrance of the fluid it contracted rapidly
to 3 divisions; after which it slowly lengthened to 7 divisions.
The experiment was repeated using another animal and the
time noted. Before the admission of the fluid the length
was 6 divisions; at entrance of the fluid contraction began
and lasted for one minute, until a length of 4 divisions was
reached; after this, the rod lengthened to 8 divisions, the
period of lengthening being 7 minutes.

Physiological Salt Solution (349% ).—Outer segments of
rods after remaining four hours in this solution showed
normal positive reaction in polarized light. In this solution,
however, a majority of the outer segments showed disinteg-
ration and distortion of form, with no refraction at all.
After three days such outer segments as were still sufficiently
intact to show any double refraction, gave reversed color
reaction; 1. e., they were anisotropic and negative with respect
to their long axes.

Amniotic Fluid.—This was obtained from pig embroys and
was kept in sterilized bottles with a small piece of thymol
as a preservative. Outer segments of rods rapidly disin-
tegrated in this fluid, possibly because of the presence of
thymol.

Egg Albumen.—As much of the fluid portion of this sub-
stance as would easily pass through a strainer of bolting
silk proved as satisfactory an examination medium as the
fluid from the eye. About 10 c.c. of liquid albumen can be
obtained from a single egg.

‘2. Fixing Agents.

In giving the results of tests with fixing fluids I have
included an account of the unsuccessful trials as well as the

No. 3.] VISUAL, CELLS? IN VERTEBRATES. 601

more satisfactory ones, since the account of failures may at
least save the time of other workers. However, in cases
where a fluid has been unsuccessful in one animal it does
not necessarily follow that it will be inapplicable to the same
tissue in another animal, though the probabilities are against it.
Again, slight modifications of a formula, or its method of
application, might meet the requirements.

Osnuc Acid Vapor.—Outer segments of rods show a
reversal with polarized light after treatment with this
reapent: The tints are more brilliant- than “normal
and the blue phase has a decided greenish cast. The
permanent preparations made by this method have already
been described (Pl. 4, Figs. 33-37). The excessive blacken-
ing of the outer segments and their contraction are char-
acteristic of long fixation. Short fixation gives appearances
much like the fresh condition, but with a slightly brownish
color.

Osnuc Acid, ¥%2% Aqueous Solution.—The outher segments
were reversed in color when seen in polarized light; curling,
breaking transversely, and lengthening occurred commonly
in the outer segments; notwithstanding these results many
segments were well preserved. Among the latter, many were
observed which gave with oblique light alternating light and
dark bands.

Vom Rath’s Fluid.—As already stated on page 5709, prepar-
ations fixed in this fluid show an exaggerated shrinkage in
leusth* CPi 4) Fiee32)):

Flemming’s Fluid (strong formula).—The outer segments
were poorly preserved by this method, but the superficial
fibrils were brought out plainly.

Absolute Alcohol.—Double refraction is destroyed; 7. e.,
with light tests the outer segments become quite transparent
and of the same color as the red field.

Formaldehyd.—In preparations made by exposure to the
vapor of formaldehyd the “optical axes,’ as shown by
the color reaction, were reversed as compared with those of

602 HOWARD. [Vot. XIX.

the fresh material. Treatment by this method did not yield
well preserved outer segments. A 40 per cent. aqueous solu-
tion destroys the double refraction of outer segments of
rods. A 4 per cent. aqueous solution gives reversal of
reaction for outer segments. The form of the rod is not
well preserved.

Nitric Acid (10% ).—This reagent causes the outer seg-
ments of the rods to elongate to almost double their original
length, but apparently they retain their former volume. This
change is accompanied by a reversal of the colors in the light
test and a loss of transparency by granulation.

Picric Acid seems to cause the loss of double refraction in
the outer segments of rods; in polarized light with the gypsum
interference plate they show the red “field color” at all angles.

Mercuric Chloride (saturated aqueous solution).—A
reversed color reaction in polarized light occurs in outer
seginents when placed in mercuric chloride. Voluntary muscle
seems to be unchanged in this optic character when sub-
jected to the same treatment. However, after Jong fixation
muscle shows the same results as the rods do.

A study of sections of the retina fixed by this method
shows a very fair preservation of the general form of the
elements, with slight contraction. The nucleoplasm is notice-
ably contracted, so as to be quite generally separated from
the nuclear membrane. Staining seems to bring out less of
the fine detail than is obtainable by some other fixatives.
The membrana limitans externa of the retina is more dis-
tinct than with other fixatives.

Mercuric Chloride + 5% glacial acetic acid gave reversal
with polarized light. A detached outer segment of a rod
under observation when the fluid was admitted, showed
suddenly a central axis, as if that portion were first affected,
then the rod curled into a horse-shoe shape. Sections fixed
in this fluid have been described above under “Permanent
Preparations.”

Zenker’s Fluid—With this reagent preservation is good

a

No. 3.] VISUAL CELLS ANG VERTEBRATES. 603

and fixation generally satisfactory, so far as I have observed.
I have used it but little.

Petrunkevitsch’s Fluid.—* This mixture causes a great deal
of vacuolation in the outer segments of the rods.

Perenyt's Fluid causes outer segments to contract trans-
versely and lengthen, probably preserving the same volume. [
should attribute this effect to the contained nitric acid, which,
when used alone, produces similar results. Vacuolation is
greater than in mercuric chloride plus 5 per cent. acetic acid.
The most marked effect in the whole visual cell is the vacu-
olation and consequent general expansion of the paraboloid.
A similar effect is produced in the nuclei. The outer segments
of cones seem to be as well preserved by this method as any
I have seen, judging by external form, and from comparisons
with fresh material.

Golgi’s Rapid Process —This method gave some indications
of selective impregnation in the details of the elements. I
was surprised and interested in this, but did not have the
opportunity to carry on trials until complete impregnation
was obtained. In other material treated by this process I
have obtained elements so densely impregnated that there was
little opportunity to make out finer cell details. The published
results of other workers (Ramon y Cajal, Dogiel, et al.)
who have used this method on the visual elements show the
whole cell impregnated. On account of these results, I did
not consider the method favorable for my special problem.

Drying.—Fixation by drying at a high temperature, in the
manner of making “blood preparations,” breaks up the outer
segments into short pieces, but these appear in natural con-
dition as to transparency and form. Light tests give normal
reaction after twenty-four hours. Outer segments dried at

*Formula:
AON COMO ts sae otics nbs dia) sche eysuet eee SOONCHC:
GlACtPy ACEC stone ee aie cae ee eecne 00°C: @
INGERICE PAC TAN arm okie seer eee oe eee LOCC?

Mercutio Chlonideltem sameeren litres 50 g.

604. HOWARD. [VoL. XIX.

room temperature disappear in a few hours, apparently by
deliquescence, leaving a drop of liquid.

3. Lntra-Vitam Stains.

Methods were considered for employing “‘intra-vitam”
stains in the living animal, but as the proportion of successful
impregnations is likely to be so small, a more practical method
was sought for. The retina as a whole was placed fresh in
examination media in which “non-poisonous stains’ were dis-
solved in very small quantities, or the stain was added while the
object was under observation to permit of watching the prog-
ress of the stain. Positive results were obtained with methy-
len blue, toluidin blue, and hematein. With Congo red and
some other dyes I obtained no evidence of selective staining.

Methylen Blue.—A retina was placed fiber layer downward
so as to leave the rods and cones vertical on the upper side
and give an end view of these elements. When methylen
blue is added the outer segments of the cones become imme-
diately deeply stained, thus the field appears as a mosaic of
larger white circles, the rods, and smaller blue ones, the cones.
In teased retinze where the rods are seen laterally, occasional
individuals may be found with transverse bands stained deep
blue alternating with light blue ones. In many cases the super-
ficial fibrils stain blue, and there is some evidence of a central
axis. The affinity of the stain for only occasional rods is
probably due to some peculiar condition in the metabolism of
the element. This selective character is in accordance with
what has been observed for this method in other parts of the
nervous system.

Toluidin Blue.—A retina was placed in fluid egg albumen
in which was dissolved one three-thousandths by weight of
ammonium molybdate; after ten to twenty minutes, toluidin
blue, one three-thousandths in egg albumen, was added. In
a few minutes the detached outer segments of the rods showed
a marked differentiation of a central axis or core staining”

— ——

es es

No 3.] VISUAL CELDS\\INUVERTEBRADES. 605

purple. This color was noticeably different from the blue in
other parts of the rod (PI. 5, Figs. 41, 42) and in the field.
In most cases this axis showed an irregular outline and dis-
continuity, as if broken by post-mortem changes, due perhaps
to the reagents. In some outer segments this stained axis
projected, at the proximal broken end, beyond the peripheral
substance of the cylinder (Fig. 42).

Longitudinal superficial fibrils stain by the above method
and also with toluidin blue alone. Whether the ammonium
molybidate was an efficient factor or not, I did not ascertain.

Hematem.—from a retina immersed for twenty-four
hours in fluid albumen containing a few crystals of haematein,
outer segments of rods were obtained which showed alter-
nating light and dark transverse bands. The bands appeared
to be the edges of disks or rings and the darker ones pro-
jected slightly beyond the lighter ones, as do the successive
segments in a muscle fibril when in a state of contraction.

Lite DPSCWUSSLON:

The various appearances presented by protoplasm or “cell
plasm” after treatment with different fixing fluids is a
matter of common knowledge. An interesting study of
such effects on nerve cells is given by Floyd (:03). I have
described some of the different appearances in the visual
cells as prepared by various reagents, and I have shown that
from this standpoint there is abundant opportunity for con-
tradictory results where workers have depended on single
preservatives.

Any ROD MCELLS:

The outer segments of the rods when prepared in osmic acid,
have been shown to possess superficial longitudinal lines when
viewed in toto. The interpretation of these lines from cross sec-
tions has been (Schultze, Greef, and others) in general that they
“depend upon a grooving of the surface which has some rela-

606 HOWARD. [Vov. XIX.

tion with a deeper differentiation in structure” (Hensen,
67; Schultze, °724,). This differentiation was observed as
regular rifts in the inner substance of the rods. But well
preserved rods, I find, do not show these rifts. In such cases
with comparatively low power (1,000 diameters) the sheath
usually appears continuous, though sometimes thinner in the
bottom of each furrow.

As I have shown (pp. 579, 590-591), the longitudinal ridges
of the outer segment in osmic material correspond with the
stained fibrils demonstrated by other methods of fixation and
with the fibrils seen in optical sections of fresh rods. Hensen’s
('67, Fig. 7) figure of the fresh rods of frogs corresponds with
what I have seen in Necturus. It seems that the longitudinal
cleavage lines occur between the fibrils and that the vacuoles
of some material are due to penetration of fluid along these
grooves, perhaps through a membrane. The appearance then
of deeper radiating lines is probably due to artifacts determined
by these peripheral structures.

Some preparations suggest the presence of a set of fibrils
or tubes parallel to the stained fibrils and alternating with
them, but I should put little reliance on such a conclusion with-
out more evidence.

The fibrils of fresh and fixed material are usually slightly
oblique, otherwise I have found no fibrils in the rods to com-
pare with: the ‘spirals ‘of Hesse: (\!'04),) or of Ritter, (ome
gt”). The evidence, such as I have obtained (Howard, : 03),
is all against W. Krause’s (’92) opinion that the transverse
cleavage is due to a system of closely wound spiral fibrils.

The fibrils which I have demonstrated in fixed material,
most satisfactorily in Necturus, but also in the frog and the
goldfish, are probably the same which Schneider (:02) has
observed in the frog, though on this point I am not quite cer-
tain, for Schneider’s description is accompanied by two small
text-figures only. It is unfortunate that he has not published
a more complete account of these “neurofibrils,”’ as he terms:
them.

No. 3.] VISUAE / GELES~ INV VERTED RA TES: 607

Schultze found no peripheral fibrils except those of the
“fiber-basket,”” which he described as running over the inner
end only of the rod and belonging to the system of retinal
sustentative cells, ““Muller’s fibers.” I have not identified any
such structure on the rods of Necturus, though some might
claim that the peripheral ‘stained fibrils,” as I have termed
them, are identical with the fibers of Schultze’s “‘fiber-basket.”’
The reasons against this view I will take up more in detail
later, and I will merely add here that the intimate structural

‘

connection of the “stained fibrils” with the outer segment and
the fact of their extension over the whole length of the seg-
ment argue against this opinion.

The large single peripheral fibril figured by Kolmer (:04)
in the frog, can hardly be identified with any structure that
I have described, unless in Kolmer’s preparations only a single
fibril was impregnated. Impregnation methods lke Golgi’s
and Bielschowsky’s, which Kolmer used, act selectively, as
all know who have worked with them. If there ts selection
here in a single element, the fact would have considerable
interest. ‘That only a single fibril might be present, as Retzius
(:05) described for the dogfish, is conceivable, in which case
this would be a simpler condition than exists 1n amphibians
and teleosts; but he figures some single rods, in which
two fibrils have been impregnated. This, it seems to me,
favors my contention that there may be selection of a single
fibril, or at least of a smaller number, in certain elements. The
same comment would apply to the fibrils described by Held
(:04). The “diplosomes’’ mentioned by these authors imply
a connection between fibrils and a couple of spherules in the
region of the ellipsoid. I have seen nothing of such relations
myself, but Iam not prepared to deny their existence.

So far, then, as I have been able to demonstrate, the
cylindrical outer segments possess peripheral fibrils run-
ning lengthwise and each fibril is raised slightly above the
surface of the cylinder.

Another character of the outer segments which has been
described is the transverse striation. This is demonstrated in

608 HOWARD. [Vor. XIX.

several ways. Its inconstancy of appearance in stained mate-
rial is probably due to a uniformity in the laminz or bands
of an individual rod, which prevents differentiation under
usual conditions. I have noted its appearance most frequently
with methylen blue in fresh rods. Rarely transverse striation
is to be seen in material stained by hematoxylin. Such a
preparation is shown in Fig. 24 (PI. 3). The cementing sub-
stance (Kittsubstanz, Greef, :00) is here evidently stained
by the hematoxylin. This condition, in connection with other
observed phenomena, has led me to suspect (see pp. 581, 596-
597) that these excessively thin layers may be nerve conduct-
ing fibrils lying between thicker plates (catoptric in function
or for isolation), and connecting on the outside of the rod
with the longitudinal fibrils. Such a structure would seem to
agree in general with that made out in invertebrate eyes
(Schultze, Hensen, Patten, Parker, Hesse). I think we must
agree that Schultze was right when he said: “However dif-
ferent the formation and development of the eyes of animals
may be in general, still for the purpose of transferring the
undulations of light to the domain of nervous conduction we
may assume a conformity in the structure of the terminal
organs” (Schultze, ’72*, p. 1006, ’72, p. 826). The pres-
ence of transverse nerve fibrils has not been demonstrated,
but such a condition would seem to be consistent with some
polarized light reactions, and a few other observations, as I
have already recorded (pp. 581, 596-597).

This hypothesis would, however, have to be supplemented
to account for such further phenomena as the high degree
of contractility and the alternating layers of optically different
substances. These suggest an analogy in structure to muscle
fibrils.

Direct observation of contraction in the outer segments of
rods, such as I have reported, has not, I believe, been pre-
viously recorded. Several workers, however, have given the
results of measurements on the visual elements examined in

animals subjected to different degrees of light and darkness,

No. 3.] VISUAL CEEES\ IN” VERTEBRATES. 609

heat, etc., which showed elongation in darkness and contraction
(as a rule) under the influence of light and heat (Hornbostel,
78; Angelucci, °85; Engelmann, ’85; Gradenigo, 85; Krause,
2.7 pe roo Llerzog; 205).

In an attempt to explain the contraction of the visual cells
we may employ a photo-contractile hypothesis (Cf. “Photo-
musculaire theorie” of Dubois et Renaut, 89) and suppose
that the final nervous impulse results from a mechanical stim-
ulation (pressure or contact) produced by an intermediate
process. The intermediate process would be the contraction
Otaarstructtre (the tree ‘portion of a rod ‘cell) extremely
sensitive mechanically to differences of light or temperature;
the contraction in response to heat or light might be conceived
as comparable to that of a muscle from the effect (heat ?) of
a motor-nerve discharge.

If to the photo-contractile hypothesis the objection were
advanced that the introduction of mechanical stimulation 1s
an unnecessary complication, it might be answered that it is
consistent with observed parallel cases,—that the sensitiveness
of a single cell to light might not be a type of stimulation
transmissible over the long distances necessary to convey an
impulse to the central nervous organs, in which case a trans-
formation by secondary stimulation would be necessary.

To correlate the above hypothesis with the theory that
rods are functional only for light of low intensities (see Rivers
:00), we would suppose that the contraction was not due
directly to light or heat but indirectly through the action of
the visual purple, the chemical character of which was changed
by light action.

That the lamine of the outer segment in their dimensions
come with the limits of the wave length of light and show
a constant thickness has been taken, by some (Schultze, Greef,
Zenker) to be of considerable significance (see p. 563).
Schultze states that nocturnal animals and others living in
diminished light have very long rods, thus increasing the num-
ber of plates. If stimulation depends on the relation of the

610 HOWARD. [Vor. XIX.

piates to wave lengths of light by some diffraction phenomenon,
then expansion or contraction of the outer segment would
necessarily affect the result by varying distances between plates.

Since I have not as yet systematically investigated the
physiology of visual cells, my suggestions are purely tentative.
Interesting as such considerations are, it must be granted that
they can be little else than speculations until we have obtained
a more complete knowledge of the structure of visual cells
as well as further information as to their chemical and physical
characters.

I wish now to discuss what I have called a “central core.”
The differentiation of this central core or axis in the outer
segment occurs so frequently that I think we cannot but assume
its existence in the living condition. When differentiated at
all, this feature occurs in fixed and stained preparations as
an unstained portion. On this account Greef (: 00) explained
the appearance as a fixation effect and due to difference of con-
sistency between the contents of the outer segment and its
sheath. This hypothesis, however, does not explain the selec-
tive staining of the core by toluidin blue in fresh material, a
fact which I consider of great weight. The irregular central
staining mass in rods treated by Mallory’s (: 00) triple stain
is probably not identifiable with this body, since its distribu-
tion is inconstant and apparently limited to the center as a
result of shrinkage only (Pl. 5, Fig. 38).

The more regular and constant appearance which I have
mentioned as an axial core suggests the axial fiber, about
which there has been so much controversy. This has beer
variously described, and, because of ambiguity in terms, it is
scarcely possible to be certain, except from figures, to what
the observations really referred. Probably the best known of
these was the axial fiber described by Ritter, the presence of
which was confirmed by Manz, Schiess, and Hensen, but not
generally admitted by others. Schultze gave the question
considerable attention, reporting (’724; ’72>, p. 821) observa-
tions of his own on fresh mammalian material. He finally

No. 3.] VISUAL CELES, IN VERTEBRATES, 611

concluded, however, that the appearance was due to optical
effects alone. It is evident in some of the references to an
axial structure that quite different objects were in the minds
of the authors. Kuhnt (see Schwalbe, ’87, p. 105) refers to
the structure of the outer segment as, ““Kornige axiale und
eine streifige periphere Substanz.” This description evidently,
like that of Schneider ( : 02), who uses the term ‘*Achsenstab,”’
refers to all the mass of an outer segment inside the peripheral
fibers, without any further differentiation within these. Dre-
ser ('86) says, “Ich konnte eine axiale Substanz nachweisen,”
and goes on to describe it as an ‘“‘Achsenkanal,” which gives
to a cross section of a rod the appearance of a ring. This
differentiation he was able to bring out only by certain chem-
ical treatments and stains. . Bernard (: 01, p. 465) in speak-
ing of the conditions in a living rod says, that a reticulum is
condenced into [7. e. to form] the axes of the rods, the reticu-
lum being replaced by an inflow or absorption of substance from
the pigment granules, through the walls of the outer segment.
The fiber of Ritter as described and figured is too small in rela-
tion to the diameter of the rod to be identified with the axial
core which I have observed. However, it seems probable from
the figures of other investigators, that the same appearance
gave rise to the various descriptions. For instance, an inspec-
tion of Hensen’s (’67) figures shows that his cross section of
the fiber are larger than they appear in the longitudinal view.
In connection with the double refraction of the outer seg-
ments I wish to call attention to some results which seem
contradictory to my own. Valentine (’62) investigated with
polarized light a large number of animal tissues including the
rods of the retina and the axis cylinders of nerves, and as
the following quotations show, he found that the reactions of
these two bodies were not alike but opposite. ‘Die nahere
Verfolgung des Gegenstandes zeigt, dass die optische Axe der
Langsaxe der Nerven parallel geht; man also hier einen wahr-
haft negativen Korper vor sich hat und die ganze Erscheinung
nur von dem Marke herruhrt” (Valentin, 62, p. 123). “Man

612 HOWARD. [Vov. XIX.

konnte theoretisch annehmen, das die Stabchen an und fur
sich nicht anders, als die markigen Nervenfasern wirken’”’
(p. 136). “Jene [Stabchen] waren aber wahrhaft positiv und
das Mark von diesen [| Nerven] wahrhaft negativ” (p. 136).

It is thus evident that Valentin believed that the optical
axes of the rods and of the nerve fibers were not in agreement,
but were at right angles to each other, and this opinion was
accepted by Max Schultze (67), Krause (’92),* and Greet
(3300))-

It is not easy to account for Valentin’s statement that the
axis cylinders of nerves are negatively anistropic, unless we
assume that in consequence of the imperfect knowledge of
nerve structure at his time he has recorded the reaction of
the medullary sheath, which 1s negative, instead of that of the
axis cylinder. Valentin’s work was done on Torpedo mar-
morata and shows that his observations were made almost
entirely upon medullated nerves. It is quite evident that
what he refers to as sheaths of the nerve must have been the
positively reacting connective tissue of the peripheral nerves,
for he makes no mention whatever of the brilliantly con-
spicuous medullary sheath as such. He does, however, speak
of pressing out the retina of a frog with a cover-glass and
finding fibers which he considers to be parts of the optic nerve.
These, he states, also showed negative reactions, but there is
no certainty that what he described were really optic nerve
fibers.

In my tests of nerves I found medullated fibers unsatis-
factory objects for clear demonstration of optical properties
in the axis cylinder, because of the strong predominance of
the reaction color of the medullary sheath. The non-medul-
lated fibers from invertebrates (crayfish) were more satis-
factory, but even here the presence of the positive Schwann’s
sheath, though comparatively thin, made conclusive observa-

**“TDie Aussenglieder sind ferner positiv doppelbrechend; die optische
Axe liegt in ihrer Langsrichtung und es ist bemerkenswert, dass sie
sich entgegengesetzt wie das bekanntlich negativ Nervenmark verhalten.”
(Krause, ’92, p. 150.)

No. 3.] VISUAL CELLS IN VERTEBRATES. 613

tion out of the question, for the color of the sheath was pro-
jected on the less strongly reacting axis.

It was, therefore, necessary to use nerve fibers without
protective coverings. The naked axis cylinders radiating trom
the entering optic nerve in the fiber layer of the retina, met
this requirement. In order to get a clear demonstration of
these, I made tests upon the retina from a perfectly fresh
ox eye, where the large size of the eye made manipulation
comparatively simple. In this case there was little difficulty in
identifying the radiating bundles of nerve fibers, which were
readily distinguishable from small blood vessels and other
structures of a fibrous nature. The bundles of naked axis
cylinders proved to be distinctly positive, thus agreeing with
the rods, and I am consequently forced to conclude that ip
some way Valentin’s observations were in_ this respect
erroneous.

The agreement in reaction to polarized light between the
outer segments of rods and the axis cylinders of nerve fibers,
though not necessarily referable to identical structure, may be
of significance. In the outer segment we would naturally
look for some association between the polarization and trans-
mission of light. According to the wave theory of light, the
vibrations are at right angles to the direction of propagation.
Since the axis of maximum elasticity is transverse in the rods
we would seem to have in them a condition most favorable
for the transmission of light rays in the direction of the
longitudinal axis. This set of conditions may be simply inci-
dental and not essential in the physiology of vision,

The reversal of polarization in the outer segments of rods
with many reagents is a phenomenon the general occurrence
of which is surprising, for one would naturally expect that
killing fluids would destroy polarization (as some do) rather
than that they would reverse it. The cause, which I only
surmise, may be the contraction of certain structural elements
producing a reversal of the conditions of stress in the body;
1. €., increasing the tension of one axis as compared with

614 HOWARD. [Vor. XIX.

that of another. Such an effect may be produced in a
cylinder of glass which under ordinary conditions is isotropic;
pressure at each end will produce polarization in the negative
optical direction with respect to the cylinder axis, while ten-
sion at the same points will produce a positive reaction to
the light. The latter would represent the normal condition
in the outer segment of the rod; 7. ¢., the axis of maximum
elasticity is at right angles to the cylinder axis.

From what has been shown as to the complex structure of
outer segments, their delicacy and sensitiveness to slight
stimulation, I think it will be unnecessary to try further to
disprove the view that they are cuticular in nature or even
secretions (pp. 567-568). Nor is there any good reason for
considering the outer segment non-nervous, for, as I have
shown, the fibrils run the whole length of the visual cell,
and these fibrils satisfy well the conditions which Schultze
('72a;"7oab. p. 827) leoked tor when he wrote:,. atone
time believed it possible to point out the way in which the
outer segment might take a share in the act of perception,
namely, by means of the fibers, discovered by me, which run
over the surface of the inner segment and are continued upon
the outer segment.”

Having considered the characters of the outer segment, we
may now take up the cell organs of the inner segment,
treating of them in the order of their occurrence from the
distal to the proximal end.

The intermediate plate, which has been observed in a
number of forms, may be of more general occurrence than
has been reported. Its small size would account for its having
been overlooked, though it is usually differentiated clearly.
The plate-like form and the fact that staining fibrils* pass
over its edge only, and not through it, suggest an isolation
function between inner and outer segments. Greef (: 00)
applied the name “Zwischenscheibe” to it, supposing that the
structure had not been previously described; but from a glance

* Fibers which Schultze finally concluded were from sustentative tissue
(Schultze, 72b, p. 823).

No. 3.] FISUAL ‘GELES MIN@ BERT BE BTKALEES, 615

at Schultze’s (’67, p. 218, Taf. 13) description of what he
calls the “Kittsubstanz,” it is evident that he referred to the
same object. The latter term has been since applied more
generally to the substance between the plates of the outer
segment. Herzog (:05) figures an intermediate plate in both
individuals of the double cones in Rana, but I am not certain
of its presence in the cones of Necturus.

The ellipsoid or its homologue is found in most vertebrates.
The name is hardly appropriate, for its usual form is not
ellipsoidal; but such a term is better than ‘‘Aussenlinse,”
which assumes that its function is dioptric. Schultze’s term,
“outer lentiform body,” has nothing objectionable except per-
haps its rather prohibitive length. In our present state of
knowledge concerning the ellipsoid, its significance, I think,
can only be surmised. I can hardly agree with Pes (:00)
in his belief that it is a nucleus and that the visual cells
extend as independent elements only to the membrana limitans
externa. It is true that aside from what is usually taken to
be the true nucleus, it 1s the distinctly chromophil portion of
the element, and might have specialized nutritive functions,
but I have not seen the slightest evidence that it ever exhibits
karyokinesis. The visual cells, so far as I know, never divide
normally in the adult animal, excepting possibly at the ora
serrata. The highly refractive and clear appearance of the
ellipsoid in the fresh condition, suggests a dioptric function,
but again the frequent occurrence of globules within its
substance is a fact not consistent with this view. That the
globules are simply coagulation products is possible, yet they
are perhaps too regular for that. In the cones of the gold-
fish the spherules are separated by equal intervals and are
very uniform in shape and size (see also Hesse, : 04, Taf. 25,
Fig. 4,6; Chondrostoma, and First, : 04, Taf. 3, Fig. 27, trout).

I have seen no connection between structures in the ellip-
soid and the fibrils which pass over its surface. If, as has
been supposed, the ellipsoid and paraboloid have each the
function of a lens, we have here an interesting adaptation of

616 HOWARD. [VoL. XIX.

two bodies, in several ways quite dissimilar, to a like function.
Contrasting them we find in the paraboloid little affinity for
stains, comparative stability after death, persistent clearness
and lower index of refraction, while the ellipsoid has a strong
chromophilic character, marked instability, rapid clouding at
death, and a higher index of refraction. Both are more
refractive than the surrounding media and have such geomet-
rical forms as to exert a marked effect on the light rays which
traverse them.

The fibrils within the sheath of the paraboloid are probably
what Hensen (’67) first described in the frog as the longi-
tudinal striation of the inner segment. Schultze spoke of
these as separate fibrils, saying that such were not demon-
strable in the outer segment. If his observations were correct
for internal and external fibrils in inner segments of the rods
in man (Schultze, ’72b; p. 824, top), then it would seem
probable that the fibrils I have described as surrounding the
paraboloid of Necturus would be the homologues of the inter-
nal fibrils.

The enveloping membrane reported by Merkel (’70) and
Landolt (’71), I have not been able to find in Necturus;
1. e., there seems to be no conspicuous membrane distinct from
the substance of the inner segment in which the longitudinal
fibrils are embedded.

Observations upon the farther course of the stained fibrils
over the proximal part of the visual cell are not numerous.
Schneider ( :02) describes these fibrils as passing over the
nucleus. Hesse (:04) gives figures for the cones of Thalas-
sochelys in which he shows spiral fibers proximal to the
nuclei. I believe Bernard (:01) would have difficulty in
upholding his contention that neurofibrils enter the nucleus.
The fibrils which Schultze describes as forming the “fiber
basket” (also Landolt, ’71) surrounding the rods in the
human retina, can hardly be identified with those I have
described. The latter converge proximally in the rod foot (PI.

2, Fig. 8) after leaving the nucleus. From the concentration in ~

.

No. 3.] VISUAL CELES IN VERTEBRATES. 617

the rod foot it is very evident that they diverge into the outer
reticular layer. If the fibrils came from the ‘‘fiber basket”’
and belonged to the Muller’s fibers, or sustentative cells,
they would in general converge toward the nuclei of these
cells located in the middle nuclear layer. Instead of this,
the fibrils in question diverge on leaving the foot process of
the visual cells.

Verheeff (:03) contends, with good reason, that the old
idea that the membrana limitans externa is made up of the
external end of the Muller’s fibers, is incorrect. He finds
a fenestrated membrane in the pigmented epithelium almost
identical with the membrana externa, and argues that since this
cannot be produced by Muller’s fibers the probability is against
that being the case in the membrana limitans externa. He finds
these fenestrated, net-like membranes present generally in epi-
thelia and believes they are produced by the epithelial cells them-
selves. Schneider (: 02) describes in epithelia what are prob-
ably identical structures as “Schlussleisten’”’ and ‘“Desmochon-
dren.” I have examined Dr. Verheeff’s excellent preparations
of the human retina, in which this fibrillar membrane shows
distinctly. I had previously seen the same in the pigmented
epithelium of teleost retinas and puzzled over its meaning.
Retzius (:05), however, shows in the pigment epithelium of
the dogfish sustentative cells producing long intercellular fibrils.
If such elements are generally present in retinal pigmented
epithelia, Verhceff’s opinion would be somewhat discredited.
However, Verhceff states that such are not present in man.

By Cone Cenis:

Every indication points to a complex structure in the
outer segments of cones and, because of their instability, to a
more difficult problem than in the corresponding part of the
rod. This peculiarity, making it difficult to obtain outer
segments of cones in the fresh condition, accounts probably
for the absence of reports as to their double refraction. That

618 HOWARD. [VoL. XIX.

the cones of some animals possess spiral fibers, seems fairly
certain. \Whether there is both an external straight system
and an internal spiral one, as maintained by Hesse (: 04),
is open to question.

The external straight fibrils in Necturus have been suf-
ficiently demonstrated. As to the inner dark staining struc-
ture, since it so frequently resembles a spiral, and since the
latter is demonstrable in some animals, the balance of evidence
would perhaps be in favour of the existence of that type of
structure. That the external fibrils have a mechanical function
(Hesse, : 04), I think is no more likely than that that should
be the office of a spiral. The high degree of contractility ia
the cone would not be inconsistent with a contractile spiral,
such as is to be seen in the stalk of Vorticella. I have observed
no sign of spiral fibrils in the inner segment of the cones of
Necturus or the goldfish, except an occasional slightly oblique
direction of the peripheral stained fibrils in Necturus. The
double circle of fibrils, as seen in cross sections of inner seg-
ments of the cones, may, however, have some special sig-
nificance, though they are, so far as I have been able to
determine, all of the same character.

CG. Dousve Cones.

The double cones of Necturus, showing the extreme of
differentiation and evident specialization for particular func-
tions, may offer a clue as to the functions of the various
parts of the visual cells, and perhaps indicate the original
line of differentiation between rods and cones. ‘The far-
‘cone, with its marked development of fibrils and other char-
acteristics, practically the same as the single cones, evidently
functions as these do, while the rear-cone, with its irregular
and enormously enlarged paraboloid and ellipsoid of dif-—
ferent form and staining qualities, must have a different office.
On the theory that the nuclei of cells in general have a
trophic function, it seems not unlikely that the near-cone

No. 3.] VISUAL. CELLS IN VERTEBRATES. 610
takes a large part in the nutrition of these joined cells. This
is suggested by the relations of its nucleus. The process
which the latter sends distally down over the side of the
paraboloid must be of significance. » The surface of the nuc-
leus is increased thereby and noticeably that part of its sur-
face which is in contact with the paraboloid and, through
the paraboloid sheath, with the more distal cell organs.
The nuclear sheath in this region seems to be very thin, or
entirely absent, especially at the distal edge of the process.
Here it is difficult to make out any distinction between nucleo-
plasm and cytoplasm, as there is no sharp differentiation in
the staining of the two. The dark staining nucleoplasm,
however, shades off gradually, as if there were some limit,
though an indefinite one The constant difference in stain-
ing reactions between the two nuclei would seem a further
indications of different functions. And again the loss of
symmetry of the near-cone as to its nucleus and paraboloid
must be associated with a loss of a light receiving office, as
rays would not have the regular disposition that must result
from the lens-shaped nuclei and paraboloid of the ordinary
visual cells.

If we seek between double and single cones a distinct
difference that might be of physiological importance in relation
to visual function, it would seem to be the greater distance
of the outer segments of double cones from the source of
light. There is evidently a rather small range of contraction
in the double cones, so that their outer segments are more
constantly remote from their nuclei. If the increased dis-
tance were an advantage for a visual function, the distance
from the nucleus might demand some new adaptation for
more direct nuclear relations.

Levi’s (:00) opinion that the double cones come from a
single embryonic cell seems quite plausible. If that is the
case, probably the nuclear division is complete while the
cytoplasmic is less so. I have distinguished two nuclei
in a great many cases and therefore do not agree with
Schultze (’67) in the opinion that only one nucleus is present.

620 HOWARD. [VoL. XIX.

IV. SUMMARY.

1. The visual rods and cones of vertebrates represent dis-
tinct and separable elements of a sensory epithelium.

2. These elements are cells, usually much elongated, having
a proximal fixed portion, containing the nucleus, and an extra-
nuclear part ending free in the “ventricle of the primary optic
bulb,’ or, more strictly, its morphological equivalent in the
adult.

3. The fixed or nuclear portion is in close contact with
other elements of the retina lying within the membrana
limitans externa. It possesses in addition to the nucleus, a
basal cytoplasmic extension, the rod-, or cone-foot.

4. The free portion (rod or cone) consists of two parts.
distinguished by chemical and optical properties, the inner and
outer segments.

5. In Necturus there are present three distinctly differ-
entiated types of visual elements called rod-cells, cone-cells,
and double cone-cells. These have the following structure :

RopyGErus:

1. The outer segment has the form of a cylinder with a
rounded distal end.

2. A sheath is demonstrable after fixation with osmic acid.
On the inner side of the sheath are longitudinal, parallel,
highly refractive fibrils, twenty to thirty in number, extending
the whole length of the segment. Usually the fibrils vary
from the strict longitudinal course so as to form a very open
spiral. They project slightly on the surface, so as to produce
a longitudinal ribbing.

3. With some stains and under certain light conditions.
the outer segment exhibits a banded appearance, as of alter-
nating narrow and broad transverse stripes. As cleavage
occurs on such lines, it seems probable that the inner substance
of the rods is arranged in plates.

4. <A further differentiation of the inner substance is an

No. 3.] VISUAL: CELES, IN« VERTREBRATES:. 621

axial portion, which is about one-quarter of the diameter of
the rod and extends the whole length of the outer segment.

5. The outer segments contain a substance resembling the
myelin of the medullated nerve sheaths. Evidence for this is
the similarity in color produced by treatment with osmic acid
and by other tests.

6. The outer segments are anisotropic with the positive
optical direction parallel to their long axes. In this regard
they agree with the axis cylinders of nerves and with muscle
fibrils. In each of these bodies, then, the axis of maxi-
mum elasticity 1s transverse to the longitudinal axis of the
fiber.

7. Outer segments in the fresh state when examined in
eye fluids show a considerable range of contraction and elong-
ation. If a very dilute foreign fluid is added, a rapid con-
traction occurs, like the reaction of a living body; this is
followed by a gradual elongation to a length greater than
the original. Elongation of a permanent character is pro-
duced by certain fluids of “fixing” strength. The contractility
and transverse striation together with other characters suggest
a possible structural analogy with muscle.

8. Between the inner and outer segments is the inter-
mediate plate. This structure appears as a barrier between
the two segments, in that the continuity seems to be inter-
rupted, except for the fibrils, which pass over the edge of the
plate.

g. The inner segment is in general form cylindrical, but
less rigid in its outlines than the outer. No sheath com-
parable to that of the outer segment seems to be present.
The proximal portion (myoid) shows considerable con-
tractility. Two enclosures in the inner segment take up most
of the space. These are the ellipsoid and the paraboloid.
Outside of these are longitudinal fibrils, which are contin-
uations of those on the outer segment. In the inner segment
they lie so deep as not to affect the contour of the surface.

10. The ellipsoid varies in form from convex-concave to
plano-concave, with the concave side proximal. It is composed

622 HOWARD. [Vor. XIX.

of a highly refractive substance strongly chromophilic. In fixed
preparations this is often resolved into globules.

11. he paraboloid has the general form implied in its
name. Distally it fits into the concave side of the ellipsoid;
proximally it 1s often pressed against the surface of the
nucleus, causing an involution of the latter. The paraboloid
can be isloated and is more stable than the ellipsoid, but less
refractive. Its substance does not stain readily. Paraboloid
and ellipsoid must exert a definite action on the rays of light
traversing them, because of their form and high refractive
index, as compared with the surrounding substance.

12. The fixed portion of the rod cell contains the nucleus
with its very thin cytoplasmic sheath, which is continued
proximally in the rod-foot. The nucleus is an oblong to ovate
spheroid in form. It is larger than the other nuclei of the
retina and contains chromatic substance, usually in a finely
divided form. Nucleoli are usually present. In the plasmic
sheath are longitudinal fibrils, continuations of those seen in
the outer and inner segments. These pass into the foot,
whence they diverge into the outer reticular layer of the
retina.

SINGLE CONE CELLS.

1. ‘The outer segments have a conical form. In Necturus
peripheral longitudinal fibrils are present, as in the rods.

2. The interior has a banded appearance, which is due
either to a lamellar structure or represents the edge of a
spiral. In the goldfish, four to five spiral fibrils are present
having a peripheral position. This system only was observed
in the outer segment, which suggests that it may be the hom-
ologue of the peripheral, stained fibrils in Necturus.

3. The composition of the outer segments of the cones
differs in several respects from that of the rods. One of
these is the presence of a substance having a marked affinity
for methylen blue, another, the presence of a small proportion.
of “myeloid” substance.

No. 3.] VISUAL CELLS 'IN VERTEBRATES. 623

4. The polarization is like that of the rod under ordinary
conditions; 7. ¢., the cone axis lies in the positive optical
direction, but the reaction is less decided. The evidence indi-
cates that there are fibrillar elements present not responding
to the predominating reaction.

5. No intermediate plate was observed in the cones of
Necturus.

6. The ellipsoid differs slightly from that of the rod cell
in 1ts reaction to stains and in its form, which is more elong-
ated in an axial direction.

7- The paraboloid seems essentially like that of the rods.
The separation between it and the nucleus is greater in the
cones than in the rods.

8. The nucleus of the cone differs from that of the rods
in being an ovate spheroid with its small end distal. In
other respects the nucleus of the cone cell seems to be like
that of the rod cell.

DouBLE Cone CELLS.

I. The double cones consist of two complete cone cells
united along their sides from their nuclei to their ellipsoids.
The two individuals are evidently specialized for different
functions, since homologous parts in each differ in form and
staining properties, excepting perhaps the outer segments,
which are not directly connected.

2. The far-cone retains the essential structural characters
of the ordinary cones and evidently has the same function
as these.

3. The near-cone is so unlike its fellow as to make it
probable that its function is different. The nuclear relations
suggest that the near-cone has a specialized trophic function
for the pair, while the special development of fibrils in the
far-cone and other considerations would indicate that its
function was more highly developed along the line of that
of the single cones.

624 HOWARD. [Vot. XIX.

GENERAL.

The fibrils which are seen in the three kinds of visual cells
and pass from the outer limbs into the outer reticular layer
seem to be intercellular neurofibrils. Their function is pre-
sumably that of conducting nerve impulses from the end-organ
to. the more central elements of the retina, ultimately to the
optic centers. That these fibrils may arise from more central
retinal elements and penetrate the more peripheral ones is
conceivable, but in my opinion they have more probably taken
their origin in the visual cells themselves.

V.. /bIBIMO GRAPE N.

Papers marked with an asterisk have not been accessible in the original.

* AncELuccI, A., 85. Una nueva teoria sobre la vision. Bol. clinica Hosp.
de Santa Cruz, No. 2, p. 20; No.'3, p. 35; No. 4, p. 54. (Jahresber:
uber Fortschritte der Anat. u. Physiol., Bd. 14, Abt. 2, p. 149.)

ApaTtHy, §., 797. Das leitende Element des Nervensystems und seine
topographischen Beziehungen zu den Zellen. Mitth. Zool. Stat. Neapel,
Bd. 12, Heft 4, pp. 495-748, Taf. 23-32.

Brernarb, H. M., :00. Studies in the Retina: Rods and Cones in the
Frog and in some other Amphibia. Quart. Jour. Micr. Sci., Vol. 43,
Pt..1,-No. 169° (CN: °S!)) pp: 23-47.) ple 3:

BERNARD, H. M., :o1. Studies in the Retina: Rods and Cones in the
Frog and in some other Amphibia. Part II. Quart. Jour. Micr. Sci.,
Vol. 44, Pt. 3, No. 175 (N. S.), pp. 443-468, pls. 30-31.

BERNARD, H. M., :02. Studies in the Retina. Parts III-V. Quart. Jour.
Mier. Sei, Vol. 46, Pt. 1, Now i8r GN. S.)y.pp.25-75.0 Diss. 3
Bernarp, H. M., :03. Studies in the Retina. VI. The Continuity of
the Nerves through the Vertebrate Retina. Quart. Jour. Micr. Sci.,

Vol. 47, Pt. 3, No. 187 (N. S.), pp. 303-362, pls. 27-20.

Berne, A., 798. Ueber die Primitivfibrillen in den Ganglienzellen und
Nervenfasern von Wirbeltieren und Wirbellosen. Verh. Anat. Gesell.,
12 Versamm., pp. 37-38.

Brpper, F., ’39. Zur Anatomie der Retina, insbesondere zur Wirdigung
der stabformigen Korper in derselben. Arch. f. Anat., Physiol. und
wiss. Med., Jahr. 1839, pp. 371-385.

* BorysrekiEwicz, M., ’87. | Untersuchungen tber den feinern Bau der
Netzhaut. Wien und Leipzig. (Centralbl. f. Physiol., Bd. 1, No. 235,
Pp. 717-719.)

* BorysSIEKIEWIcz, M., ’94. Weitere Untersuchungen tiber den feineren
Bau der Netzhaut. Wien. (Hesse, :04, p. 512.)

No. 3.] VISUAL GCEEDS EIN VERTEBRATES: 625

Brucxke, E., ’44. Ueber die physiologishe Bedeutung der stabformigen
Korper und der Zwillingszapfen in den Augen der Wirbelthiere.
Arch. f. Anat., Physiol. und wiss. Med., Jahr. 1844, pp. 444-451.

Dreser, H., 86. Zur Chemie der Netzhautstabchen. Zeit. f. Biol., Bd.
22, pp. 23-39.

Dusots, R., et RENAvT, J., 89. Sur la continuité de l’épithélium pigmenté
de la rétine avec les segments externes des cOnes et des batonnets,
et la valeur morphologique de cette disposition chez les Vertébrés.
Compt. rend. Acad. Sci., Paris, Tome 109, No. 20, pp. 747-749.

EpNer, V. von, ’o2. A. Keelliker’s Handbuch der Gewebelehre des
Menschen. 6. Aufl., Bd. 3, viii + 1020 pp., 633 Fig.

Emppen, G., :or. Primitivfibrillenverlauf in der Netzhaut. Arch. f. mikr.
Anat., Bd. 57, pp. 570-583, Taf. 29.

ENGELMANN, T. W., ’85. Ueber Bewegungen der Zapfen und Pigment-
zellen der Netzhaut unter dem Einfluss des Lichtes und des Nerven-
systems. Arch. f. ges. Physiol., Bd. 35, pp. 498-508, Taf. 2.

Froyp, R., :03. A Contribution to the Nervous Cytology of Periplaneta
orientalis, the Common Cockroach. Mark Anniversary Volume,
Art. 17, pp. 341-358, pls. 25-28.

FROMMANN, C., 64. Zur Silberfarbung der Axencylinder. Arch. f. path.
Anau. Physiol= Bd? 31, pp: 151-153, Lat. (6:

Furst, C. M., :04. Zur Kenntnis der Histogenese und des Wachstums
der Retina. Lundis Universitets Ars-skrift, Bd. 40, Afdeln. 2, Nr. 1,
pp. 1-45, Taf. 1-3.

Grecensavr, C., 798. Vergleichende Anatomie der Wirbelthiere. Bd. 1,
Leipzig, 8°, xiv + 978 pp.

* GortscHE, C. M., 736. (Title?). Pfaffs Mitth. aus dem Gebiet der
Med. Chirurg. u. Pharm., N. F., Jahrg. 2, Heft 3-4, p. 40. Arch. f.
Anat. Physiol. u. wiss. Med., Jahrg. 1837, p. viii.

* GRADENIGO, G., ’85. Ueber den Einfluss des Lichtes und der Warme
auf die Retina des Frosches. Allg. Wiener med. Zeitung, No. 29
t1.630)/11 pp., 1 Taf. (Krause,.’92:)

GrANpbRY, M., ’68. Recherches sur la Structure intime du cylindre de
Vaxe et des cellules nerveuses. Bull. de l’Académie Royale de
Belgique, sér. 2, tome 25, pp. 304-316, I pl.

GREEF, R., :00. Die mikroskopische Anatomie des Sehnerven und der
Netzhaut. Grefe-Semisch Handb. d. Gesamt. Augenheilk., Bd. 1,
Kap. I, 212 pp.

GRENACHER, H., ’79. Untersuchungen tuber das Sehorgan der Arthropoden,
insbesondere der Spinnen, Insecten und Crustaceen. Gottingen, 4to,
viii + 188 pp., 11 Taf.

Hanover, A., ’40. Ueber die Netzhaut und ihre Gehirnsubstanz bei
Wirbelthieren, mit Ausnahme des Menschen. Arch. f. Anat., Physiol.,
u. wiss. Med., Jahrg. 1840, pp. 320-345.

626 HOWARD. [Vov. XIX.

Herp, H., :04. Zur weiteren Kenntnis der Nervenendftisse und zur
Struktur der Sehzellen. Abhandl. d. math.-phys. Klasse d. Konigl.
Sachs. Gesell. d. Wiss., Bd. 29, No. 2, pp. 145-185, 1 Taf.

HENLE, J.,’39. Anmerkung zum vorigen Aufsatz. (R. Remak, zur mikros-
kopischen Anatomie der Retina.)’ Arch. f. Anat., Physiol. u. wiss.
Med., Jahrg. 1839, pp. 170-175.

HeENsEN, V., ’65. Ueber das Auge einiger Cephalopoden. Zeit. f. wiss.
Zool., Bd. 15, pp. 055-242; Tat. 12-21.

HeEnsEN, V., 67. Ueber das Sehen in der Fovea centralis. Arch. f.
path. Anat., Phys., u. Klin. Med., Bd. 39, pp. 475-492, Taf. 12.
HeENSEN, V., 768. Bemerkungen zu W. Krause, die Membrana fenestrata

~ der Retina. Arch. f. mikr. Anat., Bd. 4, pp. 347-350.

Herzoc, H, :05. Experimentelle Untersuchungen zur Physiologie der
Bewegungsvorgange in der Netzhaut. Arch. f. Anat. u. Physiol.,
Jahrg. 1905, Physiol. Abt., Heft 5 u. 6, pp. 413-464, Taf. 5.

Hesse, R., :00. Untersuchungen uber die Organe der Lichtempfindung
bei niederen Thieren. VI. Die Augen einiger Mollusken. Zeit. £
wiss. Zool., Bd. 68, Heft 3, pp. 379-477, Taf. 25-32.

Hesse, R., :o1. Untersuchungen tber die Organe der Lichtempfindung
bei niedern Thieren. VII. Von der Arthropoden-Augen. Zeit.
f. wiss. Zool., Bd. 70, Heft 3, pp. 347-473, Taf. 16-21.

Hesse, R., :03. Uber den Bau der Stabchen und Zapfen der Wirbeltiere.
Verhandl. d. Deutsch. Zool. Gesellschaft, 13, Jahresversammlung, pp.
33-41.

Hesse, R., :04. Ueber den feinern Bau der Stabchen und Zapfen einiger
Wirbeltiere. Zool. Jahrb., Suppl.-Bd. 7, pp. 471-518, Taf. 25.

HorFMAnn, C. K., 775. Amphibien, in H. G. Bronn, Klassen und Ord. des
Thierreichs, Bd. 6, Abt.2, 726, pp., 52 Taf.

* HorNpostEL, F. von, ’78. (Title?) Untersuchungen aus dem physiol.
Institut zu Heidelberg, Bd. 1, Heft 4, pp. 409-411. (Krause, ’92, p. 228.)

Howarp, A. D., : 03. On the Structure of the Outer Segments of the Rods
in the Retina of Vertebrates. Amer. Nat., Vol. 37, No. 440, pp. 541-550.

Jounson, G. L., ’95. Beobachtungen an der Macula lutea. 2. Die Schicht
der Stabchen und Zapfen. Arch. f. Augenheilk., Bd. 33, p. 337-344,
2° Dat

KO.LLIKER, A., '52. Zur Anatomie und Physiologie der Retina. Verh.
phys.-med. Gesell. Wurzburg, Bd. 3, pp. 316-336.

KoumMer, W., :04. Ueber ein Strukturelement der Stabchen und Zapfen
der Froschretina. Anat. Anz., Bd. 25, No. 4, pp. 102-104.

* Krause, W., ’68. Die Membrana fenestrata der Retina. Leipzig, 8°,
59 pp., 2 Taf. (Schultze, ’722.)

Krause, W., ’92. Die Retina. Internat. Monatschr, f. Anat. u. Physiol.,
Bd. 9, pp. 150-236, Taf. 11-13.

No. 3.] VISUAL CELLS IN VERTEBRATES. 627

Krause, W., ’95. Die Retina. Internat. Monatschr. f, Anat. u. Physiol.,
Bd. 12, pp. 46-186, Taf. 2-7.

LAnbo.t, E., 71. Beitrag zur Anatomie der Retina vom Frosch, Salaman-
der und Triton. Arch. f. mikr. Anat., Bd. 7, pp. 81-100, Taf. 9.

Ler, A. B., :05. The Microtomist’s Vade-Mecum. Ed. 6, Philadelphia, 8°,
x + 538 pp.

* Levi, G., :00. Osservazioni sullo svilluppo dei coni e bastoncini della
retina degli Urodeli. Lo Sperimentale, anno 54, PP. 521-539, 1 Tav.
(Ergebnisse der Anat. u. Entwickelungsgesch., Bd. 10; .:) 422)

Leypic, F., ’55. Zum feineren Bau der Arthropoden. Arch. f. Anat.
Physiol. u. wiss. Med., Jahrg. 1855, pp. 376-480, Taf. 15-18.

Lryonic, F., 64. Vom Bau des thierischen Korpers. Tubingen, 8°, vi ++ 278
Pp., 10 Taf.

Ma.tory, F. B., :00. A Contribution to Staining Methods. Jour. Applied
Microscopy, Vol. 3, pp. 1036-1038.

Mattory, F. B., :05. A Contribution to the Classification of Tumors.
Jour. Med. Research, Vol. 13, No. 2, PP, 113-136, pls. 5-8.

Mann, G., :02. Physiological Histology. Oxford, 8°, xvi + 488 pp., 1 pl.

* Manz, W., 61. Ueber den Bau der Retina des Frosches. Zeit. f. ration-
elle Med., Reihe 3, Bd. 10. (Hoffmann, Se)

* Manz, W., 66. Die Ganglienzellen der Froschnetzhaut. Zeit. f. ration-
elle Med., Reihe 3, Bd. to. (Hoffmann, ’75.)

MERKEL, F., ’70. Zur Kenntniss der Stabchenschichte der Retina. Arch. f.
Anat., Physiol. u. wiss. Med., Jahrg. 1870, pp. 642-650, Taf. 14.

MERKEL, F., ’92. Sinnesorgane. Ergebnisse der Anat. u. Entwickelungs-
gesch., Bd. 1, pp. 233-255.

MicHaELis, G. A., ’37. (Referat iiber Michaelis’ Arbeit nach dem Manu-
script.) Arch. f. Anat. Physiol. u. wiss. Med., Jahrg. 1837, p. xii.

MU.ter, H.,’52. Bemerkungen iiber den Bau und die Function der Retina.
Verh. phys.-med. Gesellsch., Wurzburg, Bd. 3 pp. 336-340.

Mttier, H., ’56. Anatomisch-physiologische Untersuchungen iiber die
Retina bei Menschen und Wirbelthieren. Zeit. £. wiss. Zool., Bd. 8,
PDs i-i22) Lat 1-2

Nissx, F., :o1. Die Neuronlehre vom pathologisch-anatomischen und
klinischen Standpunkt. Verh. Gesellsch. deutsch. Naturforsch. u.
Aerzte, Versamml. 72, Theil 1, pp. 211-234.

Norris, W. F., anp WALLACH, J., ’94. A contribution to the Anatomy of
the Human Retina, with a special consideration of the terminal loops
of the rods and cones. Univ. Med. Mag., Philadelphia, Vol. 6, pp. 353-
358, 3 figs.

ParKeER, G. H., ’95. The Retina and Optic Ganglia in Decapods especially
in Astacus. Mitth. Zool. Stat. Neapel, Bd. 12, Heft 1, pp. 1-73, pls. 1-3.

Patren, W., ’86. Eyes of Molluscs and Arthropods. Mitth. Zool. Stat.
Neapel, Bd. 6, Heft 4, pp. 542-756, pls. 28-32.

628 HOWARD. [Vov. XIX.

Patten, W., ’98. A Basis for a Theory of Color Vision. Amer. Nat.,
Vol. 32, pp. 833-857, 10 figs.

Pres, O., :oo. Sulla fina anatomia dei membri esterni delle cellule visive
nella retina umana. Giorn. Accad. Med., Torino, Anno 63, p. 162-168.

Prentiss, C. W., :03. The Neurofibrillar Structures in the Ganglia of the
Leech and Crayfish with especial reference to the Neurone Theory.
Jour. Comp. Neurol., Vol. 13, pp. 157-175, pls. 5-6.

Ratu, O. vom., ’95. Zur Conservirungstechnik. Anat. Anz., Bd. 11, pp.
280-288.

Rauper, A., :03. Lehrbuch der Anatomie des Menschen. Bd. 2. Leipzig,
8°, viii + 968 pp.

Rerzius, G., :05. Zur Kenntniss vom Bau der Selachier-Retina. Biol.
Untersuch., N. F., Bd. 12, No. 5, pp. 55-60, Taf. 6.

Ritter, C., 59. Ueber den Bau der Stabchen und ausseren Endigungen der
Radialfasern an der Netzhaut des Frosches. Arch. Ophthalm., Bd. s,
(2 Abth.), pp. ror-111, Taf. 4.

Rirrer, C., ’918. Zur Histologie der Zapfen der Fischretina. Internat.
Monatschr. f. Anat. u. Physiol., Bd. 8, pp. 128-134, Taf. 7.

Rirrer, C., ’91b. Studien tiber die Stabchenschicht der Vogel. Internat.
Monatschr. f. Anat. u. Physiol., Bd. 8, pp. 241-249, Taf. 14.

Rivers, W. H. R., :00. Vision. In E. A. Schafer, Text-Book of Physi-
ology. Edinburgh and London, 8°, Vol. 2, pp. 1026-1148.

ScHArer, E. A.,’97. Organs of the Senses. Quain’s Elements of Anatomy,
London, 8°, Vol. 3, Part 3, 165 pp., 178 figs.

* ScHIESsS, 63. Beitrag zur Anatomie der Retinastabchen. Zeit. f. ration-
elle Med., Bd. 18. (Greeff, : 00.)

SCHNEIDER, K. C. :02. Lehrbuch der vergleichenden Histologie der Tiere.
Jena, 8°, xiv + 988 pp., 691 Abbild.

SCHULTZE, M., 66. Zur Anatomie und Physiologie der Retina. Arch. f.
mikr. Anat., Bd. 2, pp. 175-286, Taf. 8-15.

ScHULTZE, M., 67. Ueber Stabchen und Zapfen der Retina. Arch. f. mikr.
Anat.) Bd: 3iepp. 265-247.) hala

SCHULTZE, M., ’698. Die Stabchen in der Retina der Cephalopoden und
Heteropoden. Arch. f. mikr. Anat., Bd. 5, pp. 1-24, Taf. 1-2.

Scuuttze, M., "69>. Ueber die Nervenendigung in der Netzhaut des
Auges bei Menschen und bei Thieren. Arch. f. mikr. Anat., Bd. 5,
PP. 379-403, Taf. 22.

ScHuLtze, M., ’71. Neue Beitrage zur Anatomie und Physiologie der
Retina des Menschen. Arch. f. mikr, Anat., Bd. 7, pp. 244-259, Taf. 20.

SCHULTZE, M., 724. Die Retina. In S. Stricker, Handbuch der Lehre von
den Geweben, Bd. 2, pp. 977-1034, 18 Fig.

ScHuize, M., ’72b. The Retina. In S. Stricker, A Manual of Histology.
Edited by A. H. Buck. New York, 8°, pp. 802-847.

No. 3.] VISUAL. CELESY IN VERTEBRATES. 629

ScHWALBE, G., 87. Lehrbuch der Anatomie der Sinnesorgane. Erlangen,
8°, xiii + 570 pp., 199 Fig.

SMITH, G., :06. The Eyes of Certain Pulmonate Gasteropods, with
Special Reference to the Neurofibrille in Limax maximus. Bull. Mus.
Comp. Zoél. Harvard College, Vol. 48, No. 3, PP. 231-283, 4 pls.

* TREVIRANUS, G. R., ’36. Beitrage zur Aufklarung der Erscheinungen und
Gesetze des organischen Lebens. Bd. 1, Heft 2, p. 42. Papillen der
Netzhaut des Auges. Bd. I; Heit 3; poop, Nachtrage, Taf. 3-6. (Arch,
f Amat, Physiol u. wise. Med., Jahrg. 1837, Jahresbericht ; Greeff,
: 00.)

* VALENTIN, G; “61. Die Untersuchung der Pflanzen. und der Thiergewebe
in polarisirtem Lichte. Leipzig, 8°, vi + 312 pp., 3 Taf. (Valentin,
1625)

VALENTIN, G., ’62. Histologische und Physiologische Studien. Zeit. £.
rationelle Med., Reihe 3, Bd. 14, pp. 122-181.

Veruoerr, F. H., :03. A hitherto undescribed Membrane of the Eye and
its Significance. Boston Med. Surg. Jour., Vol. 149, pp. 456-458.
Wiardse S500: «On the Morphology of the Compound Eyes of Arthro-
pods. Studies Biol, Lab. Johns Hopkins Univ., Vol. 4, No. 6, pp.

287-334, pls. 29-35.

WIEDERSHEIM, R., ’86. Lehrbuch der vergleichenden Anatomie der Wirbel-
thiere. Jena, Auflage 2, xiv + 890 pp., 614 Fig.

ZENKER, W., 67. Versuch einer Theorie der Farben-Perception. Arch. {.
mikr. Anat., Bd. 3, PP. 249-262.

VI. EXPLANATION OF PLATES:

All figures are from Preparations of Necturus, except where otherwise
stated. All, with the exception of Figures 22 and 46, were drawn with the
aid of the camera lucida.

The magnifications are indicated in the descriptions of each plate, and
the means of obtaining them are shown in the following table:

OBJECTIVE | MAKER OcuLarR MAKER oe Macnirication
ENGTH IN DIAMETERS
E Zeiss No. 3 Zeiss 136 mm. 830
E Zeiss Sheth clemA Zeiss 130m goo
13 Zeiss sn Zeiss Igo. * 1300
a Zeiss Tate Zeiss E36: a | 3800
Tz Leitz See a Zeiss 1365s ee 1450
. Leitz Ny Zeiss 1305 uN 1000
Soe ne Wetez Bes Zeiss TaiG, 1450
“| Leitz ars: Zeiss ce 1850
eS | Fuess pee Fuess 1000
No. 9 Fuess oan Fuess 450
No. 5 Fuess ee Fuess | 300

630

HOWARD.

ABBREVIATIONS.

ax. cyl., axis cylinder.

bac. vir., green rod.

cl. pig. rtn., retinal pigment cell.
con., cone.

con’., double cone.

con. dst., far cone.

con. prx., near cone.

cp., corpuscle of fibril.

dsc., plate.

dsc. 1’m., intermediate plate.

ell., ellipsoid.

ell. bac., ellipsoid of rod.

ell. con., ellipsoid of cone.

ell. con. dst., ellipsoid of far cone.
ell. con. prx., ellipsoid of near cone
forl., fibril.

gran. ell., granules of ellipsoid.

gtt. ol., oil globule.

ivly., sheath.

ivlr. nl., nuclear sheath.

ivlr. pa’b., sheath of paraboloid.

ivlr. prs. dst., sheath of outer segment.
med., axial core.

mb. lim. ex., membrana limitans externa.
my., myoid.

my. bac., myoid of rod.

my. con., myoid of cone.

my. con. dst., myoid of far cone.
my. con. prx., myoid of near cone.
nl., nucleus.

nl. bac., nucleus of rod.

nl. con., nucleus of cone.

nl. con’., nucleus of double cone.

nl. con. dst., nucleus of far cone.
nl. con. prx., nucleus of near cone.
nil., nucleolus.

pa’b., paraboloid.

pa’b. bac., paraboloid of rod.

pa’b. con., paraboloid of cone.

pa’b. con. dst., paraboloid of far cone.
pa’b. con. prx., paraboloid of near cone.
pd. bac., foot of rod.

pd. con. prx., foot of near cone.
pd. con., foot of cone.

pd. con’., foot of double cone.

pd. con. dst., foot of far cone.

pre. cl. pig., process of pigment cell.

[VoL. XIX.

No. 3.]

pre.
prs.
prs.
prs.
prs.
prs.
prs.
prs.

prs.

VISUAL CELLS INVERTEBRATES.

nl., nuclear process.

dst., outer segment.

dst. bac., outer segment of rod.

dst. con., outer segment of cone.

dst. con. dst., outer segment of far cone.
dst. con. prx., outer segment of near cone.
prx., inner segment.

prx. bac., inner segment of rod.

prx. con., inner segment of cone.

st. nl. ex., outer nuclear layer.

st. nl. m., middle nuclear layer.
st. pig., pigment layer. -

st. ret. ex., outer reticular layer.

vac.,
vsl.,

vacuole.
vesicle.

631

PEALE au

All figures are from Necturus and are magnified 1,450 diameters. All
preparations were fixed in corrosive-acetic mixture and stained in Heiden-
hain’s iron-alum-haematoxylin.

Fic. t1—Two rods and one cone as seen in a radial section of the
retina. The small rod at the right shows the peripheral system of stained
fibrils. "These are seen most distinctly at low focus; 7. e., on the lower
surface of the rod. The sides are out of focus. Small portions of the rods
are broken away at the distal end. (Cf. other figures.)

The paraboloid (pa’b. bac.) of the large rod, drawn in optical section,
is clearly eccentric, a condition not very rare. The nucleus and other parts
are shown from a focus at the near surface.

The cone (on the left) has an appearance typical of this material.
‘The outer segment is much vacuolated and with only a slight general
stain. Superficial fibrils show faintly and are slightly oblique. The fibrils
over the paraboloid are more distinct. The paraboloid itself is out of focus.

The heavily stained granules are characteristic of the ellipsoid
(ell.) of the cones.

Fic. 2—The double cones showing the marked differentiation between
the individual elements of the couplet. In A the couplet is seen laterally;
i. e., both cones are in the plane of section. In B the couplet lies in a
plane at right angles to that of the section, and the far cone, only, is in
focus. A comparison of the different views of the myoids (my. con. dst.)
in the far cones in A and in B shows the flattening of the myoid.

Fic. 3.—Cross section of an outer segment of a cone; the surrounding
elements are in outline only. ‘The peripheral, stained fibrils are seen in
section and also obliquely lengthwise; they are separated by some little
space from the dark stained center.

Fic. 4, A.—Cross section of a cone through the paraboloid. The
stained fibrils occur in two concentric circles, neither of which is on the
surface.

Fic. 4, B.—Cross section of a rod through the paraboloid; the fibrils
are closer to the paraboloid than to the surface.

Fic. 5, A——Cross section of a double cone through the paraboloid of
the near cone, and the myoid of the far cone. :

Fic. 5, B—Cross section of the distal end of a nucleus of a rod
showing fibrils in the surrounding cytoplasm.

Fic. 6.—Cross section of the ellipsoid of a rod. The stained fibrils are
superficial. The ellipsoid granules are distributed through the central
portion.

>

VISUAL CELLS IN VERTEBRATES- HOWARD

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All figures are from Necturus. Figures 7 to 11 are magnified 1,450
diameters; Figures 12 to 16 are magnified 1,000 diameters.

Fic. 7—A large rod, slightly separated from its nucleus, and a double
cone, the near cone in focus. In the latter, superficial fibrils are visible
at the base of the outer segment, passing over the ellipsoid, paraboloid,
and nucleus, and converging proximal to the nucleus in the cone foot.
The fibrils of the rod in this particular preparation are more diffuse in
the region of the foot than those in the foot of the neighboring cone. The
material was fixed in corrosive-acetic mixture and stained in Mallory’s
triple stain (Mallory, : 00).

Fic. 8.—A single rod showing the relation of the stained fibrils to the
nucleus and the rod-foot. The fibrils of adjacent elements are distinct
until they diverge at the outer reticular layer of the retina. The nucleus
of the rod in the center has shrunken away from its sheath, at its
proximal end. The parabaloid in optical section gives the appearance of a
coarse blue reticulum. The fixation and stain were the same as in Fig. 7.

Fic. 9.—A cross section of the outer segment of a rod. The fibrils are
distinct when seen in section. As a rule, vacuoles alternate with the fibrils.

Fics. 10-11.—A cone and a rod, fresh, in normal fluids of the eye, and
drawn in situ a few minutes after the removal of the retina from the living
animal. Only a small portion of the nucleus of the rod is shown. The
changes which so rapidly set in upon the death of the animal have already
begun here. The outer segment of the cone, most unstable of all, shows
evidence of disintegration; granulation has commenced in the ellipsoids
and is more pronounced in the nuclei. The parabaloid remains compara-
tively clear for some time. The latter is more refractive than the sheath,
but less refractive than the ellipsoid. In the cone (Fig. 10) the paraboloid
is a great deal more flattened than usual. A common relation of paraboloid
and nucleus for fresh cones is shown in PI. 3, Fig. 20.

Fics. 12 to 16.—Outer segments of fresh rods in fluid from the eye,
showing progressive disintegration. Figures 12 to 14 were drawn within
half an hour after the rods were removed from the eye. In Figure 12 the
upper surface is in focus and only one diagonal is visible, while in Figure
13, where the lower surface is in focus, several of the diagonals (fibrils)
are visible. The difference in the number of lines visible is apparently due
to the optical effect of the cylinder. Figure 14 represents the appearance
of a rod at the very lowest focus at which lines are visible. The more
highly refracting fibrils are dark in low focus, while the less refractive
intermediate substance appears light.

Fic. 17.—An outer segment of a fresh rod seen in optical section.
This view was obtained by laying a portion of a retina flat on a slide and
focusing upon the rods in situ. In a retina thus examined the crenated
edge of rod outer segments is very apparent, and in many instances where
disintegration has commenced, radial fissures of variable length are to be
seen extending inward from the sinuses. ‘The rods that are still intact
show at first sight a homogeneous center with a crenated sheath; by close
inspection this sheath proves to be made up of separate bodies (the fibrils
in section). These are brought out more distinctly where the rods are
illuminated by a direct light from the side.

PLATE 2.

VISUAL CELLS IN VERTEBRATES—HOWARD

pd. con, —— -— ~ -

pa’b, bac-— 4

Fig. 13° Fig. 14.

Fig. 12

Fig. 15

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Figures 18, 19, 21, 23 and 24 are magnified 1,450 diameters; Figure
20 is magnified 1,000 diameters.

All the preparations, except that shown in Figure 22, were fixed in
corrosive-acetic mixture and stained with Heidenhain’s iron-alum-hzema-
toxylin; all are from Necturus, except Figures 18, 109.

Fics. 18, 19.—Visual elements of goldfish seen in radial sections of
the retina. In Figure 19 the three different types of elements, rods, cones
and double cones are shown as they occurred in actual section. ‘The rods
with long, thread-like inner limbs occur at varying distances from the
membrana limitans externa. The double cones with long inner limbs are
more distal than the single cones. The outer nuclear layer consists of four
or five strata of large cone and smaller rod nuclei.

In Figure 18 a double cone is shown in detail, only one of the
couplet, however, being in focus. In the outer limb two to four spiral
bands are seen. These do not correspond in number or in size with the
straight parallel fibrils of the inner limb, seen just distal to the nucleus.
The light area proximal to the ellipsoid is probably the homologue of the
paraboloid in amphibians.

Fic. 20.—A portion of retina embracing the pigment layer and part
of the outer nuclear layer. A rod and single cone are shown in detail and
a double cone in outline. The end of the outer segment of the rod is sur-
rounded by processes from the pigment cells. The nuclei and inner seg-
ments are in optical section; the outer segments in superficial focus.

Fic. 21.—The near cone of a double cone showing plate-like structure.
Vacuolation on opposite sides between alternate “plates” gives a spiral
appearance. Superficial fibrils are visible at the Proximal end of the outer
segment.

Fic. 22.—A fresh cone in fluids from the eye and shortly after removal
from the eye. The animal from which this was taken had been kept in
the dark three days. This treatment induced elongation of the cone, but
probably not to the extent seen here. The extreme elongation is a char-
acteristic form assumed by the outer segments of cones upon the death of
the organism. This outer segment gave the negative reaction with polar-
ized light, being yellow when at right angles to the a axis of the gypsum
plate.

Fic. 23.—A cone typical of heavily stained material. In the center
of the outer segment are structures which do not persistently retain the
hematoxylin stain. The appearance is that of plates connected by a lightly
stained axis. Their oblique relation to the latter suggests a spiral, made up
of a continuous band or broad fiber. However, an entirely satisfactory
demonstration of such a spiral has not been secured in Necturus. At the
distal end of the outer segment superficial fibrils are visible, which take a
direction slightly oblique to the long axis of the cone. Between the
nucleus and ellipsoid the superficial fibrils are straight. ‘The paraboloid
is drawn a little more distinctly than it would appear if the fibrils had been
in focus.

Fic. 24—Outer segment of a rod showing evidence of “plate”
structure of great regularity.

Fic. 25.—A portion of a cone. Distinctly staining, superficial fibrils
are visible on the fragment of the outer segment. The ellipsoid is densely
stained with hematoxylin.

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Figures 26-31, 37, from the frog; Figures 32-36, from Necturus.
Figures 26 to 31 are magnified 1,300 diameters; Figure 32, 1,450
diameters; Figure 33, 900 diameters; Figure 34, 3,800 diameters: and
Figures 35-37, 1,000 diameters.

Fic. 26.—Outline drawing of visual cells from the frog retina in situ.
The outer nuclear layer is two nuclei deep. In the red rods the inner
segments are short; in the green rods the myoid portion of the inner
segments is long. The cones are much smaller than the rods and
contain an oil globule between the outer segment and the ellipsoid.

The material was fixed in Perenyi’s fluid and stained with Heiden-
hain’s iron-alum-hzmotoxylin.

Fic. 27.—A single rod from the group shown in Figure 26. Detail
is shown at the distal end of the outer segment and over the whole
of the inner segment. Longitudinal peripheral fibrils are visible on
the outer segment over the intermediate plate and on the myoid of
the inner segment.

Fic. 28. Cross sections of outer segments of the same material as
that shown in Figures 26 and 27. A central axial portion is differentiated
from the peripheral part. The latter is subdivided by lines which cor-
respond in number with the longitudinal fibrils on the surface.

Fic. 29.—A red rod from a radial section of the retina of a frog.
An axial core is visible in the whole outer segment. In the inner limb
is a body corresponding to the paraboloid in Necturus. The material was
fixed in corrosive-acetic mixture and stained in Heidenhain’s iron-alum-
hematoxylin and orange G.

Fic. 30—Cross section of the outer segment of a rod from the
same material as that shown in Figure 209.

Fic. 31——A green or short rod from the frog as seen in a radial
section of the retina including the pigment layer. The fixation is the
Same as for the preparation shown in Figure 29; the preparation was
stained with fuchsin.

Fic. 32—Visual cell of Necturus fixed in vom Rath’s fluid.

The outer segment is very much blackened and contracted. In a
thin section the longitudinal grooving appears as light lines in the dark
substance of the outer limb.

Fic. 33.—Rod and cone cells of Necturus fixed five minutes in osmic
acid fumes and isolated in glycerine.

The individuality of the cells is demonstrated. The osmic acid has
induced rather forcible contraction of the inner segments and the cleav-
age in the outer segments of the cone is excessive.

Fic. 34.—Cross section of the outer segment of a Necturus rod,
fixed in osmic acid fumes and seen under high magnification. The

(Continued on next page.)

PLATE 4.
(Continued from preceding page.)

sheath, which has stained very black, is shown thicker in the drawing
than is commonly seen. The light spaces beneath the sheath seem to cor-
respond to the fibrils of material stained in hematoxylin.

Fics. 35, 36.—Longitudinal and cross sections of a rod of Necturus
fixed in osmic acid fumes. The grooving of the outer seginent appears
as alternating light and dark lines in the thin longitudinal section (Fig.
35). In the cross section (Fig. 36) of the outer segment the grooving
appears as crenations of the boarder. Inside of the black sheath the
light zone appears continuous at this magnification.

Fic. 37——Cross sections of the outer segments of the rods from a
frog. The fixation and magnification are similar to those of Figures
35 and 36. No crenation of the edge is distinguishable, but an outer black
sheath and an inner light band can be seen.

.

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PLATE s

Figures 38 and 45 are magnified about 1,000 diameters; figures 39
and 40, 1,450 diameters; figures 41 and 42 about 1,100 diameters.

Fic. 38.—Visual elements as seen in a radial section of the retina
of Necturus, showing different~ staining qualities. The ellipsoids of
single cones and of far cones stain alike. Those of the near cone
and of rods also stain alike. All outer segments of cones stain alike
The outer segments of rods contain a blue staining reticulum in additior.
to the substance that stains with fuchsin. ‘The material was fixed in
corrosive-acetic mixture and stained with aniline blue, fuchsin, orange
G., phospho-molybdic acid, ete. (Mallory :00).

Fic. 39—Thin section of a cone from the same material as that
shown in Figure 38. The substance of the ellipsoid, staining with fuchsin,
is in the form of globules, the arrangement of which gives some suggestion
of rows. Superficial fibrils staining blue are visible between the ellipsoid
and the nucleus.

Fic. 40—A field of the outer segments of visual cells from the same
material as that shown in Figure 38. The superficial blue fibrils are
seen as dots in both rods and cones. One rod is drawn in detail. In
this the peripheral portiors are much vacuolated and devoid of substance
staining in fuchsin.

Fics. 41, 42.—Isolated outer segments of rods in natural fluid from
the eye, but containing a trace of ammonium-molybdate followed by
toluidin blue. A central portion has taken up the blue stain in a some-
what irregular war. The irregularity is probably due to a post-mortem
disintegration. In Figure 42 the central staining core projects beyond the
peripheral substance.

Fic. 43—A field containing fresh isolated rods and a cone in eye-
fluids as seen with a polarizing microscope having a gypsum interference
plate. The latter when inserted between the Nicol prisms gives as a
field color, red of the first order, while bodies in the field possessing
polarity are yellow or blue according as their axes of maximum elasticity
lie at right angles or parallel, to the a axis of the gypsum plate. This
test shows that the long axes of the outer segments of both rods and
cones are in the positive optical direction, indicating the short axis 1s
that of maximum elasticity. The outer segment of the cone shows
a much less decided reaction than that of the rod, while the inner
segments of both show the neutral field color.

Fic. 44.—A single medullated nerve fiber from the sciatic nerve
of the frog as seen by the same color test as that described under
Figure 43. The medullary sheath shows a very decided double refraction
with the axes of minimum elasticity radial with respect to the axis-
cylinder. The reaction of the axis cylinder, though not decided in this
instance, is discernible as opposite in character to that of the sheath.

(Continued on next page.)

PLATE 5.
(Continued from preceding page.)

When the sheath is absent the reaction of the axis cylinder is seen to be
unmistakably the same as that of the outer segments of the rods; 7. e.,
the longitudinal axis is the positive optical direction.

Ic. 45.—Outer segments of a rod and cones from a Necturus that had
been kept in the dark three days. The outer segment of the cone gives the
long axis as the negative optical direction instead of the positive as
usual.

Fic. 46.—Diagram showing the polarization color reaction observed
in the visual rod of the slug Limax maximus. The fibrillar structure
is shown in black as figured by Dr. Grant Smith (: 06) from a preparation
fixed in vom Rath’s platino-osmo-acetic mixture.

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