Comparative Anatomy and Embryology of 
Vertebrates as Aids in the Teaching 
of Human Anatomy in the 
Medical Course. 
GEORGE S. HUNTINGTON, M.D., 
BY 
NEWYORK. 
FROM 
THE AMERICAN JOURNAL OF THE MEDICAL SCIENCES, 
December, 1898. THE 
COMPARATIVE ANATOMY AND EMBRYOLOGY 
OF 
VERTEBRATES AS AIDS IN THE TEACHING OF HUMAN 
ANATOMY IN THE MEDICAL COURSE.1 
GEORGE S. HUNTINGTON, M.D., 
NEWYORK. 
I feel some diffidence in addressing the Association on the subject 
of my title, for I have before me, through the courtesy of Prof. Wilder, 
papers and pamphlets dealing more or less definitely with the general 
question involved, written by Hyrtl, Waldeyer, and Turner among 
foreign anatomists, and by Wilder, Allen, Baker, and Minot among 
our own countrymen, and the list proves that the matter has received 
due thought and consideration at the hands of the ablest investigators 
and teachers of our science. If, notwithstanding, I bespeak some of 
your time and attention, it is not because I wish to repeat what has 
already been said by the eminent men quoted far better than I could 
hope to express it, but because the question is a many-sided one, and 
because I desire to emphasize certain aspects of the same in their prac- 
tical bearing on anatomical instruction at our medical schools. 
I may state at the outset that I do not propose to discuss the question 
whether comparative anatomy should be included as a separate depart- 
ment of study in the medical course ;2 but, as my title indicates, I wish 
i Read before the Association of American Anatomists, Tenth Session, at Cornell University, 
December 30,1897. 
2 Wilder, Burt G. Should Comparative Anatomy he Included in a Medical Course? Mew 
York Medical Journal, October, 1877. 
Wilder, Burt G. The Anatomical Uses of the Cat. lB7p. 
Turner, William. Address at the opening op the Axjyatorhical 'Department in the new medi- 2 
HUNTINGTON: AIDS IN TEACHING ANATOMY, 
to bring before you the employment of both comparative anatomy and 
embryology of vertebrates as aids in instructing medical students in 
human anatomy. Nor do I desire to speak of the advantages of pre- 
liminary work in comparative anatomy and embryology to students 
intending to enter the medical curriculum, beyond adding my testimony 
to the effect that the value of such preliminary work cannot, in my 
experience, be overestimated, I have occasion annually to compare the 
work and progress of a large number of students from all parts of the 
country and to note that almost without exception the men who early 
demonstrate their ability are those who have received practical biological 
training during their college course. 
The questions which I wish to present for your consideration deal with 
the situation which confronts us, I believe, at the majority of our large 
centres of medical education, where students, differing necessarily widely 
in mental attainments, quantity as well as quality of preliminary train- 
ing, meet to enter the medical curriculum, and are almost at once intro- 
duced to the study of human anatomy. 
I may add that we have at Columbia during the past six years ear- 
nestly and systematically employed in our instruction in human anatomy 
the aids which the development and morphology of the lower verte- 
brates offer, so that the method upon which I can report to you has, to 
a limited extent, stood the practical test of experience. 
The advances of the last decade in the biological sciences have changed 
and modified, in important and vital details, the method and scope of 
morphological instruction. Among the special departments in our large 
universities the one charged with teaching the structure of the human 
body to medical undergraduates should perhaps be the first to avail 
itself of these wider views and broadened fundamental lines. Human 
morphologists have long occupied a peculiar position in relation to their 
subject of study. For over two centuries the most minute and pains- 
taking care has been bestowed on the investigation of man’s structure, 
both the gross anatomy and the histology of his tissues receiving exhaus- 
tive attention. The results, embodied in almost countless volumes and 
pamphlets, make man to-day morphologically the best-known vertebrate. 
cal building of the University of Edinburgh, October 27,1880. Reprinted from the Lancet, 
November 6 and 13, 1880. 
Minot, Charles Sedgwick. A Grave Defect in our Medical Education. March, 1882. Reprint. 
Baker, Frank. The Rational Method of Teaching Anatomy. Read before the Biological 
Society of Washington, D. C., November 30,1883. New York Medical Record, April 19,1884. 
Waldeyer, Prof. Dr. Wie soil man Anatomie lehren und lernen ? Rede gehalten zur Feier 
des Stiftungstages der Militar-arztllchen Bildungsanstalten am 2. August, 1884. Berlin, 1884. 
Baker, Frank. What is Anatomy? A lecture delivered Octobers, 1887, at the opening of 
the anatomical course at the Medical Department of the University of Georgetown, Washington, 
D. C. New York Medical Journal, October 22,1887. 
Allen, Harrison. Addresses in Anatomy: I. Comparative Anatomy as a Part of the Medi- 
cal Curriculum. 11. On the Teaching of Anatomy to Advanced Medical Students. Philadel- 
phia, 1891. HUNTINGTON; AIDS IN TEACHING ANATOMY. 
3 
This accrued knowledge is at our disposal, and is receiving constant 
additions, as from time to time one field after another of human anat- 
omy is revised and studied with modern methods of investigation. I 
believe that our duty as teachers of this knowledge requires us to take 
cognizance, thoroughly and systematically, of the structural relationship 
of man to the remaining vertebrates; to incorporate comparative anat- 
omy and embryology more completely in our course of instruction to 
medical students to a degree and in a manner which the following pages 
will present briefly for your consideration. 
In the first place I believe that we should not lose sight of what we 
may term the liberal scientific education of our students, as opposed to 
the acquisition of purely technical professional knowledge. Even a few 
years ago many fundamental facts of comparative anatomy and evolu- 
tion were the scientific property of a limited number of special investi- 
gators. But with the general growth of education, especially within the 
direct sphere of influence of our large universities, much of this knowl- 
edge has become diffused among the laity. It is almost superfluous to 
mention the wide educational effect of institutions like the American 
Museum of Natural History, the Army Medical Museum, or the 
National Collection. 
In his relation to the community at large the physician is still par 
excellence the man of science, and I believe that as a matter of general 
scientific education he should possess a knowledge, founded on his uni- 
versity course, which will enable him to give information and express 
intelligent opinions on vertebrate morphology in general and in relation 
to the structure of man. 
But, aside from this general aspect, the study of comparative forms is 
of the greatest possible practical benefit to the medical student. I 
vividly recall my own student days, and I cannot but sympathize with 
the feeling, more or less akin to despair, with which many students begin 
to apply themselves to the minute details of structure taught in human 
anatomy. It seems to me that it is wise to compare our system of 
instruction with that usually adopted in some other branches of scien- 
tific and mechanical education. It would be universally acknowledged 
a wrong course of procedure if a student of mechanical engineering 
were taught the constructive details of a modern locomotive, or of the 
quadruple expansion engines of an ocean steamer, before he had been 
offered the opportunity of examining and studying the simple piston, 
cylinder, or boiler; or if a course in electricity commenced with the 
dynamo, before taking up the magnet. And yet I believe that in many 
respects we err in the same direction if we place before our students the 
multitudinous details which the structure of a highly developed and 
specialized vertebrate like man offers, without availing ourselves of the 
advantages which the comparison with simpler and more evident forms 4 
HUNTINGTON: AIDS INI TEACHING ANATOMY. 
possesses both in respect to morphology and the physiological appli- 
cation of structure to function. 
I am aware that in the last years much progress has been made in the 
direction indicated, especially in the teaching of human anatomy from 
the developmental stand-point. My plea to-day is for the further elab- 
oration of this method and for the systematic use of comparative anat- 
omy in teaching the structure of the human body to medical students. 
Even with the best intentions it is not always possible fully to utilize 
the help which embryology offers in explaining the details of compli- 
cated adult human structures. I believe firmly that lasting knowledge 
is only attained by bringing the student into direct contact with the 
object of his study. The very nature of embryological methods pre- 
sents difficulties in this respect, for practical laboratory work in embry- 
ology is a sine qua non for successful instruction, and drawings or models, 
schematic or otherwise, do not replace the actual object if we seek to 
elucidate adult structures by developmental facts. Hence comparative 
anatomy steps in to fill an important gap in our available methods, 
enabling us to present in tangible shape the fundamental facts in the 
development of the higher mammalian forms, our own included, by 
properly selected preparations of lower types which preserve throughout 
life morphological conditions that are temporary and evanescent embry- 
onic stages in the higher forms. Where possible, I believe a course of 
practical laboratory embryology should be offered to medical students, 
and my ideal of such a course would be one which puts into each stu- 
dent’s hand preparations designed to illustrate, as they do forcibly and 
unequivocally, the main structural facts as permanent conditions in the 
adult lower vertebrates, while he is studying, microscopically, by section 
or reconstruction, the same conditions as temporary embryonal stages in 
the development of the higher forms. We tell our students that the 
mammalian pancreas develops as a double diverticulum of the duodenal 
loop, and thus explain the connection of the pancreatic ducts with this 
portion of the intestinal tract. I believe that this fact would impress 
itself far more permanently if at the same time they were able to 
examine a selected series of pancreatic structures and pyloric caeca, 
beginning, for instance, with the double diverticulum of Lophius and 
working through representative Teleost types to the pancreas of higher 
forms. The very fact of the morphological variations and the probably 
different physiological adaptations encountered in this portion of the 
intestinal tract in lower vertebrates, together with the variations in the 
arrangement of the pancreatic and biliary ducts in mammalia, render a 
serial study of this kind all the more valuable. Again, I know of no 
method which will teach the medical student in a short time more about 
the structure of the penis than to demonstrate to him a series of rep- 
tilian copulatory organs, where at a glance he can see the morphological HUNTINGTON; AIDS IN TEACHING ANATOMY. 
5 
principles underlying the development of the mammalian corpus spongi- 
osum and urethra, conditions which he will invariably recall when he 
examines his first clinical case of hypospadias. I cannot burden you 
with further examples; they suggest themselves by the score; but I 
believe you will agree with me if I add that one demonstration of the 
simple carnivore or marsupial intestinal tract and peritoneum is worth 
tons of colored chalk and acres of blackboard in elucidating the mys- 
teries of the “ greater and lesser sac.” 
So much, briefly, for the connection of comparative anatomy with the 
practical laboratory course in embryology. If I may trespass further 
on your time, I should like to point out what in our experience has 
proved the proper place for the introduction of comparative anatomy 
into the general course on adult human anatomy. 
I may state again, that in constructing the anatomical course at 
Columbia the guiding principle has been found in the conviction that 
the student will gain his lasting and valuable knowledge only by direct 
study of the cadaver. We have broken—l hope for good and all—with 
the didactic lecture in anatomy as commonly understood, and I may 
take a moment to outline our procedure, because it directly involves the 
question in hand. The first-year student attends no lectures in anatomy. 
During this year the instruction consists of practical demonstrations to 
small sections of the class, dealing with the anatomy of the extremities, 
the osteology, myology, and angiology of the head and neck, including 
the cervical plexus, and in direct connection with the demonstrations 
abundant practical work in the dissecting-room. The first-year student 
also attends a series of demonstrations forming what we term the “ Pre- 
liminary Visceral Course,” designed to afford that general information 
regarding the body cavities and contents which is required for the cor- 
rect appreciation of the instruction offered by the Departments of Physi- 
ology and Histology. 
In the second year, the laboratory Avork continuing, the student 
attends demonstrations to sections of the class in the anatomy of the 
central nervous system, organs of special sense, and cranial nerves. 
The entire second-year class attends three lectures a Aveek on the anat- 
omy of the body cavities and viscera. The preparations illustrating 
these lectures are, in the afternoons of the lecture days, demonstrated 
again separately to sections of the class, enabling each man carefully fo 
inspect and study the same. In this way the opportunity is given of 
making the anatomical lecture Avhat, in my opinion, it should strive to 
be—not an attempt to teach anatomy at long range to three hundred 
men at once, but an occasion for presenting a general view of the broad 
morphological principles Avhich underly the construction of organs, 
apparatus, and systems. It is here that the significance and impor- 
tance of the structural peculiarities of man can best be accentuated 6 
HUNTINGTON: AIDS IN TEACHING ANATOMY. 
and illustrated in all tlieir bearings by comparison with the morphology 
of the lower vertebrates. A series designed to teach the evolution of a 
complicated human organ, through successive stages from the simple 
and rudimentary form found in the lower vertebrates, or, conversely, the 
phylogenetic history of a human vestigial organ serially illustrated, 
attracts the student’s attention and interest from the outset. He is 
offered actual facts and preparations, not dry statements or schematic 
drawings, and the knowledge cannot fail to be more readily acquired and 
more throughly assimilated. “ Seeing is believing,” in anatomy as else- 
where. At times, in dealing with broad general themes and subdivisions 
of the subject, as the genito-urinary tract, the digestive system, etc., I 
find it desirable to present a bird’s-eye view of the structures under 
discussion by bringing before the students series of representative forms 
from all the vertebrate classes and orders before proceeding to details. 
Here the projection of photographs of the actual preparations by means 
of the lantern gives excellent satisfaction, although it does not, in my 
opinion, replace the personal examination of the object at close range. 
I may conclude by outlining, in the case of a single organ, the scope 
and extent of the comparative method as we have used it profitably in 
practice. I have selected the lung, because a subsequent communica- 
tion which I have to make to the Association on the mammalian epar- 
terial bronchial system will enable me to present my illustration in a 
somewhat more complete form. 
We begin our study of the respiratory system with a brief considera- 
tion of the physiological significance of the structures involved, as illus- 
trated by the following scheme (Fig. 1). 
Fig. i. 
R.M. Respiratory membrane. A. Afferent vessel. E. Efferent vessel. C. Respiratory capil- 
lary net-work. O. Medium containing oxygen. 
Scheme of respiratory apparatus. 
In addition to tegumentary respiration two general types of verte- 
brate respiration are to be recognized, depending upon the character of 
the oxygen-medium, whether water or air, and presenting corresponding 
structural modifications: 
1. Medium; Water; respiratory organ : gills. 
2. Medium ; air; respiratory organ : lung. 
We begin with respiration and the connected portion of the circula- 
tory system in a representative fish, and select the selachian skate (Raja HUNTINGTON: AIDS IN, TEACHING ANATOMY. 
7 
occellata) because it affords peculiar facilities for demonstration (Figs. 2 
and 3). 
The afferent arterial system proceeds from the truncus arteriosus of 
the single-chambered ventricle, dividing into caudal and cephalic 
branches, of which the former supplies three, the latter two branchial 
arteries to the gills (Fig. 2). These vessels carry venous blood returned 
Fig. 2, 
Heart, afferent branchial arteries, and gill-arches of Raja occellata; ventral view. 
to the heart by the ducts of Cuvier emptying into the single auricle. 
The blood, after traversing the gill capillaries and becoming arterial- 
ized, is collected by a corresponding number of efferent branches which 
pass caudad and mesad on the dorsal aspect of the oesophagus, uniting to 
form the aorta which distributes the blood to the body, to be returned 
by the systemic veins to the auricle of the heart (Fig. 3). 8 
HUNTINGTON: AIDS IN TEACHING ANATOMY. 
The type here represented can be reduced to the following scheme 
(Fig. 4). 
If now we assume that one gill on each side (the fifth) is replaced by 
a lung in the evolution of air-breathing vertebrates, and the correspond- 
ing arterial arch (the fifth) divided by the aortic septum from the sys- 
temic artery and converted into a pulmonary artery, the remaining four 
gills being no longer required, the continuity of the four cephalic arte- 
Fig. 3. 
Dorsal view of gill-arches, efferent vessels, and aorta of Baja occellata. 
rial arches will be restored. We will then have, with the divided heart 
and truncus arteriosus necessitated by the establishment of a pulmonary 
respiration, the following arrangement, which will be recognized as the 9 
HUNTINGTON; AIDS IN TEACHING ANATOMY. 
fundamental type-plan in the development of the arterial system of all 
lung-breathing vertebrates.1 (Fig. 5.) 
That the above assumption is justified is shown by the arrangement 
of the circulatory system in the perennibranchial amphibia; and the 
lung-fishes, and the circulatory system of Necturus and Menopoma, as 
well as that of Gemtodus, are here introduced as demonstrative objects. 
(Schematically represented in Figs. 6, 7, and 8.) 
Fig. 4. 
1. Afferent branchial artery. 2. Capillary net-work of gill. 8. Efferent branchial artery 
4. Aortic root. 5. Aorta. 
Scheme of circulation of Raja occellata. 
The points which our consideration of the subject so far has developed 
may be summed up as follows : 
1. Unity of structural plan in all vertebrates. 
2. Physiological equivalence of gill and lung. 
1 The development of the heart and arterial system has been considered in the course prior 
to the taking up of the respiratory system. 10 
HUNTINGTON : AIDS IN TEACHING ANATOMY. 
3. Pulmonary respiration and the necessary concomitant changes in 
circulation cause tlie transformation of the simple two-chambered (venous) 
fish heart into the four-chambered (arterio-venous) heart of the higher 
air-breathing vertebrates. 
4. The arterial arches pass ventro-dorsad around the foregut, uniting 
to form the aorta on the dorsal aspect of the canal. 
Fig. 5. 
Scheme of circulation in a lung-breathing vertebrate. 
1-5. Aortic arches. 6, 6. Aortic roots. 7. Aorta. 8, 8. Lungs. 9. Right (pulmonary) ven- 
tricle. 10. Left (systemic) ventricle. 
Hence in anomalous persistence of both right and left aortic arches 
in man the trachea and oesophagus are included within a vascular loop. 
(Demonstration of correlated human aortic variations.) 
We next turn to the derivation of the lung which, as above assumed, 
supplants the gill. Here again we begin with the type presented by 
the fish. 
The gill-clefts of the fish correspond to the visceral clefts formed 
during the embryonic stages of the higher vertebrates. HUNTINGTON: AIDS IN TEACHING ANATOMY. 
11 
Complete clefts are formed by protrusions from the wall of the fore- 
gut, pouches extending laterally and finally perforating externally, 
establishing a passage between the pharyngeal cavern and the surface. 
The number and arrangement of the clefts in the fish vary. In the 
embryos of the higher vertebrates there are usually four or five. 
Caudad of the last gill-cleft in the fish an additional protrusion of 
the wall of the gut forms the “ swim-” or “ air-bladder,” variable in 
development and purely hydrostatic in function. Three types of the 
swim-bladder are now exhibited : 
1. Selachian (Raja). Bladder absent, except possibly represented by 
a rudimentary diverticulum of the dorsal pharyngeal wall. 
Fig. 6. 
1. Aiferent branchial artery. 2. Capillary net-work of gill. 3. Efferent branchial artery, 
4. Aortic root. 5. Pulmonary artery. 6. Lung. 7. Aorta. 
Scheme of circulation in the Perennibranchial Amphibia. 
2. Ganoid (.Acipenser). Bladder present, connected with the lumen 
of the oesophagus by a hollow stalk, the ductus pneumaticus. 
3. Teleost (Gadus). Bladder variable in its occurrence, more or less 
reduced. The ductus pneumaticus persists in a few forms in a rudimen- 
tary condition. 
In most forms the bladder loses its original connection with the oesoph- 
agus and becomes entirely closed. The contained “ air,” composed of 
varying proportions of oxygen, nitrogen, and carbon dioxide, is derived 12 
HUNTINGTON: AIDS IN TEACHING ANATOMY. 
from the blood, which in the branchial circulation absorbs air from the 
water and again gives it off from a “rete mirabile” placed on the 
internal surface of the swim-bladder. 
Au examination of the cod’s bladder demonstrates the following 
points : 
1. A closed sac, no communication with the oesophagus existing 
Fig. 7. 
Scheme of circulation in the Dipnoi. 
1. Cephalic aortal arch. 2, 3, 4. Capillary net-work of gills connected with 2d, 3d, and 4th 
arches. 5. Pulmonary arch. s'. Ductus arteriosus. 5". Pulmonary artery. 6. Aortic root. 
7. Aorta. 8. Swim-bladder or lung. 
2. Lateral prolongations and blunt processes, resembling the mar- 
ginal diverticula of some reptilian lungs. 
3. Cephalic narrow tubular prolongations, possibly associated with 
the acoustic apparatus. 
4. On the internal surface of the ventral wall the vascular “ rete 
mirabile.” HUNTINGTON : AIDS IN TEACHING ANATOMY. 
13 
Turning now to the development of the lung in the higher verte- 
brates, we find that in them the organ first appears as a pouch pro- 
truded from the foregut and connected with its lumen by a short and 
wide canal, just as in the fish the swim-bladder in its original condition 
continues caudad the series of branchial pouch protrusions from the 
foregut. (Fig. 9.) 
Fig. 8. 
Scheme of circulation of Ceratodus. 
1, 2, 3, 4. Aortic arches. V, 2', 3', 4'. Gill capillaries of corresponding arches. 4". Pulmonary 
artery. 5. Capillary net-work of swim-bladder or lung. 6. Pulmonary vein. 7. Cardinal veins. 
8. Aorta. 9. Ventricle. 10. Auricle. 11. Truneus arteriosus. 
Hence, both the air-bladder of the fish and the lung of the higher 
vertebrates is ontogenetically a pouch protruded from the foregut. In 
its further development the pouch divides, and the canal uniting it to the 
oesophagus (ductus pneumaticus) lengthens. The divided pouch forms 
the bilateral lung; the duct becomes converted into the trachea and 14 
HUNTINGTON: AIDS IN TEACHING ANATOMY. 
Fig. 9. 
Schematic representation of development of lungs. 
1. (Esophagus. 2. Trachea. 3, 3'. Lungs. 4, 4'. Bronchi. 
Fig. 10. 
Schematic sagittal section of head and neck, showing connection of laryngeal and pharyngeal 
canals. HUNTINGTON: AIDS IN TEACHING ANATOMY. 
15 
laryngeal apparatus. The connection of the latter throughout life with 
the cavity of the pharynx preserves the original opening leading from 
the foregut into the canal of the pneumatic duct. (Figs. 10 and 11.) 
The main conclusions which can be based on the foregoing consid- 
erations are the following : 
1. Both the air-bladder of the fish and the lung of higher vertebrates 
are, ontogenetically, protrusions of the wall of the foregut. The 
bladder, usually derived from the dorsal wall, is purely hydrostatic in 
function. The lung, always connected ventrally with the foregut, is 
respiratory in function. 
Schematic profile of embryo lung. 
1. (Esophagus. 2. Trachea. 3. Lung. 
2, Both the bladder of the fish and the lung of the higher vertebrate 
embryo continue caudad the series of the visceral pouches. Hence, 
phylogenetically, probably both bladder and lung represent a last 
caudal pair of visceral pouches which have not perforated to form 
visceral clefts. 
The morphological homology of the two structures may be further 
accentuated by the following considerations ; 
1. The internal gill-pouches of the cyclostomes. Form demon- 
strated ; Bdellostoma stouti (Fig. 12), where the branchial sacs appear as 
dilatations of a tubular canal connecting the oesophagus with the exterior. 
2. The arrangement of the swim-bladder of Folypferus (Fig. 18), 
presenting ; 
a. A ventral oesophageal opening. 
h. A laryngeal-like aditus surrounded by a sphincter. 
c. A pneumatic canal, repi’esenting the trachea. 
d. A bilobed bladder, the right accompanied by the vagus nerve. 
3. The structures in Lepidostens, presenting: 
a. A laryngeal apparatus, connected with the beginning of the 
pneumatic duct. 
h. A vascular trabecular net-work on the internal surface of the 
bladder, foreshadowing the batrachian and reptilian lung. 16 
HUNTINGTON: AIDS IN TEACHING ANATOMY. 
4. The structures in the Dipnoi, where the swim-bladder develops 
directly as a lung, the pulmonary aditus presenting the same arrange- 
ment as in other forms the entrance from the oesophagus into the 
pneumatic duct. 
Pig. 12. 
Foregut, branchial pouches, and canals of Bdellosloma stouti. 
The arrows are passed through two of the narrow external openings into the oesophagus 
traversing the branchial canals and the internal gill-pouches. 
The architecture of the lung is next considered in reference to the 
bronchial tree and pulmonary vascular supply. The following series is 
employed in demonstrating the evolutions of the compound mammalian 
lung from the simple air-sac. 
Form demonstrated ; Ceratodus. 
1. Necturus. Type of perennibranchiate amphibian lung, consisting 
of simple thin-walled air-sac. 17 
HUNTINGTON: AIDS IN TEACHING ANATOMY. 
3. Python molurus, Agkistrodon piscivorus. Ophidian lung, consist- 
ing of lung-sac directly continuous with trachea; air-cells and trabeculm 
in cephalic portion, gradually becoming less and less 
marked in thin-walled distal portion. Unequal de- 
velopment of right and left lung. 
2. Rana. Batrachian lung. Simple sac, with air-cells. 
Fig. 13. 
4. Iguana tuherculata. Lacertilian lung; air-sac 
with one complete septal partition and air-cells in 
cephalic portion, simple in distal portion. 
5. Chelydra serpentaria. Chelonian lung, with 
complete septal system, dividing lung into bronchial 
spaces, dorsal and ventral. Monopodic type of di- 
vision of bronchial and pulmonary vascular system. 
6. Thalassochelys caretta, Loggerhead turtle. Che- 
lonian lung presenting direct transition to type of 
avian and mammalian lung; a single axial stem- 
bronchus and pulmonary artery, with monopodic 
system of division. 
The details of structure of the mammalian bron- 
chial tree and pulmonary vascular supply are dem- 
onstrated by a series of corrosion preparations, special 
stress having been laid upon the probable evolution- 
ary stages leading to the asymmetrical arrangement 
of the right and left bronchial system common to 
man and most mammalia. I have a subsequent 
communication on this subject to place before the 
Association, and will consequently defer the details 
until the presentation of my second paper. 
The detailed morphology of the human respiratory 
tract is next taken up from the descriptive, topo- 
graphical, and medico-surgical stand-point. I may 
add that of the nine lectures which I usually devote 
to the lungs, two are utilized for the presentation of 
the comparative and developmental facts above out- 
lined, the remaining seven dealing with the details of structure in man. 
It is quite apparent that, in order to carry out the system, much time 
and care must be devoted to the formation of a morphological museum 
for purposes of illustration. My time and space do not permit me to 
enter into a consideration of this important subject, the keynote to the 
solution of the entire problem. But I hope on some future occasion 
to bring before this Association our plans relating to the formation of 
a museum of human and comparative anatomy. 
Swim-bladder of 
Polypierns. 
1. Larynx-like open- 
ing into swim-bladder. 
I may in conclusion add, in order that I may not give a somewhat 
erroneous impression, that the department of anatomy at Columbia 18 
HUNTINGTON; AIDS IN TEACHING ANATOMY. 
offers laboratory work in comparative anatomy to medical students in 
the form of special practical courses in which every student makes his 
own dissections on fresh material and records his observations in notes 
and drawings. The number of applicants for these courses, which are 
optional, and the earnest and intelligent character of the work done give 
ample evidence of the educational value of comparative anatomy in 
the medical school. The Medical News. 
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A Quarterly Digest of New Methods, Discoveries and Improvements in 
the Medical and Surgical Sciences. 
Edited by HOBART AMORY HARE, M. D. 
$lO.OO PER ANNUM. 
** y PROGRESSIVE MEDICINE” will be modelled upon an entirely novel plan and will 
present in an original, narrative form a clear statement of the practical advance made in 
every department of medicine and surgery during the year, each specialty being dealt 
with by a single authority whose reputation gives ample assurance of accuracy and completeness. 
The personal impress of the contributor will be upon each subject; his thoroughly digested narrative 
will present its data in due and instructive connection, enchaining the interest, economizing time, yet 
giving ample and detailed consideration to all matters which will prove of real value in actual 
practice. 
Four volumes will be issued each year, the first appearing on March Ist, 1899, and the others 
following at intervals of three months. Each will contain from four to five hundred octavo pages, 
abundantly illustrated and handsomely bound in cloth. 
Expecting appreciation of the self-evident utility of such a work to all practitioners, the pub- 
lishers confidently anticipate a circulation so general as to justify the very moderate subscription 
price of ten dollars for the four volumes. All expenses of delivery will be prepaid. 
THE FOLLOWING FAVORABLE COMBINATION RATES ARE AVAILABLE. 
Alone In Combination 
e American Journal of the Medical Sciences $ 4.00) __ I 1 1 
g Medical News 4.00/ 3’7-5° i . I 
B Progressive Medicine 10.00 j I * 5-75 1 $16.00 
® Medical News Visiting List 1.25 J 
"*• Medical News Formulary 1.50, net J 
v 
0. In ail $20.75 for $16.00 
“Progressive Medicine,” with the “American Journal” or “Medical News,” will be supplied at 
$13.00, or the “American Journal,” “Medical News,” “ Visiting List” and “Formulary” at $8.50. 
LEA BROTHERS & CO.. Publishers. { 
Alone In Combination