Herth tas pee ars ere rojotoseSerceess Digitized by the Internet Archive in 2009 with funding from Ontario Council of University Libraries http://www.archive.org/details/anatomicalrecord19bard Reh ss mu ai i A ‘ : ae a” 2 eset ..” rs ae a> Aa THE ANATOMICAL RECORD EDITORIAL BOARD Irvinc Harpesty WarRkEN H. Lewis Tulane University Johns Hopkins University CLaRENcE M. Jackson Cxarigs F. W. McCiure University of Minnesota Princeton University Tuomas G. LEE Wiruram S. Minter University of Minnesota University of Wisconsin Freperic T. Lewis FLORENCE R. SaBIn Harvard University Johns Hopkins University GerorcE L. STREETER University of Michigan G. Cart Huser, Managing Editor 1330 Hill Street, Ann Arbor, Michigan VOLUME 19 JUNE—NOVEMBER, 1920 pee ve 4 a2 \VZ PHILADELPHIA A THE WISTAR INSTITUTE OF ANATOMY AND BIOLOGY hae Baga! 1/0 ° i ¢\? Yi, i’ n ht! 7, ‘ ® xs Serf hae Vir os oi i | GL ' yi : , Jef j 4 > met \ 4 Grits oh ae ode - —— er lal A FAS a 4 / ee ~e . | ae | « e CONTENTS NO. 1. JUNE Joun SHELTON Horstey, Jr. A description of a six-legged dog. Sixteen figures....... Howarp B. ApELMANN. An extreme case of spina bifida with dorsal hernia in a calf. PPR IG Seat le) iolcto cer aycys) siaia craves cyejsic Bee Mee AD) ere | vi 2a ‘ee 4 -_ Resumen por el autor, John Shelton Horsley, Jr., Universidad de Virginia. Descripcién de un perro con seis patas. El presente trabajo es una descripcién detallada de la anat externa e interna de una perra j6ven que posefa un par adici de patas posteriores bastante normales y colocadas siméti mente. Este ménstruo presentaba un par de pelvis y vagina separados en el lado izquierdo, dos vejigas — un solo rifién, un uréter impar en conexi6n con la vejiga izqui un solo intestino delgado, dos colon, dos ciegos con sus spondientes apéndices, glindulas suprarrenales pares y literos provistos cada uno de un tubo uterino y un ovario tibias de las patas supernumerarias estaban fusionadas. Translation by José F. Nonidez Cornell University Medical College, N.Y. AUTHOR’S ABSTRACT OF THIS PAPER ISSUED BY THE BIBLIOGRAPHIC SERVICE, MAY 10 A DESCRIPTION OF A SIX-LEGGED DOG JOHN SHELTON HORSLEY, JR. Department of Anatomy, University of Virginia SIXTEEN FIGURES On January 11, 1919, Mr. John R. Raines, a farmer living near the University, brought to Prof. H. E. Jordan’s laboratory a dead female dog with an extra pair of hind legs. The thoracic and abdomnial cavities were opened and the dog at once placed in a 10 per cent solution of formalin. This specimen was subsequently turned over to me for study and description. The work was done in the Laboratory of Histology and Embryology under the supervision of Professor Jordan, to whom I am greatly indebted for the privilege. From Mr. Raines were secured the following data: The dog was born October 7, 1918; died from exposure to cold the night of January 9, 1919. Her father was a shepherd, her mother a bull-terrier; both parents were apparently normal. The litter included in addition to this abnormal individual one normal brother and three normal sisters. The six-legged puppy appeared in life otherwise normal and healthy, and was apparently but little inconvenienced in walking and running by the extra pair of legs, which she carried slightly raised above the ground. The unpaired tail was apparently under perfect control. EXTERNAL APPEARANCE As regards the shape and general appearance of the head this dog more nearly resembled a fox-terrier, and she was about the size of this type of dog (fig. 1). With the exception of the nip- ples, she appeared normal cephalad of the umbilicus. With the exception of the tail and anus, she was double caudad of this point. 1 to JOHN SHELTON HORSLEY, JR. Closer examination revealed the following details: The leg, vagina, anus, and tail of the left side were displaced about 1 em. laterad of their normal relative position with respect to the ver- tebrel column. The sagittal plane of the proximal portion of the tail made an angle of 25 degrees with that of the vertebral column. The right leg was displaced slightly forward and dex- trad of its normal position. It was slightly smaller than the left leg and presented a rather undeveloped appearance, especially in the size of the thigh muscles. Between these two legs hung the extra pair of legs. The pair was inclined a little to the right of the medial line and it was enveloped in a common integument as far distally as the ankles. The members of the pair were of approximately equal size and represented genuine hind legs. Barring a very slight ventral bend at the level of the knees, the pair was extended in a straight line and it was placed in such a way that the pads of the feet faced toward the ground when the dog was standing. The pair measured 18.5 em. from the heads of the femurs to the tips of the toes. These extra legs were only slightly more slender and shorter than the other two hind legs. Palpation indicated a fusion of the tibiae, a conclusion con- firmed by roentgenograms (figs. 2 and 3) and subsequent dis- section. The extra legs articulated with the medial surfaces of the opposite halves of the paired pelves slightly forward, and to the right, of the root of the tail. There was no second tail or anus, but there was a second set of external genitalia 2 em. below and to the right of the articulations of the extra pair of legs. The vertebral column in the region of the sacrum seemed abnor- mally wide on the right side and presented abnormal landmarks, description of which will be reverted to subsequently. Just be- low the right side of the double knee there was a roughened scar- like area, whose significance will also be indicated below. SIX-LEGGED DOG 3 INTERNAL ANATOMY Osteology The vertebral column contained the usual number of vertebrae, namely seven cervical, thirteen thoracic, seven lumbar, three sacral, and nineteen caudal (fig. 2). It remained single through- out and was normal as far as the seventh lumbar vertebra, which latter was normal on the left side, but presented a large well- rounded mammillary process that was fwisted dorsally and slightly caudally extending on the same level with that of the corresponding vertebral spine. The sacrum was very slightly bent to the left. On the right the articular surface of the first sacral vertebra was turned dorsally, and accordingly produced a slight elevation. There was also on the right side an oblong, irregular plate of bone that measured 10 mm. in length, 7 mm. in thickness, and 6 mm. in the vertical plane (fig. 4, 7). It was fused with the first and second sacral vertebrae, and represented a second deformed sacrum. On the left side the sacropelvic ar- ticulation was normal with the exception of a small piece of bone, 8 mm. in length, which jutted out caudally from the left ilium at the level of the sacrum and was fused with the second and third sacral vertebrae. There was a gentle curve to the left, formed by the first three caudal vertebrae, the first of which articulated on its right side with the base of the fused ilia. The remaining caudal vertebrae were normal. Two pelves were present (fig. 3). At first observation there seemed to be a smaller medial pelvis fused dorsally to a larger and practically normal ventral pelvis; but after closer examina- tion of all of the related structures the conclusion was reached that the condition was one of lateral fusion between a right and left pelvis. The course of the unpaired sciatic nerve is the only obstacle to the latter interpretation. The right and left lateral ilia were of normal size (figs. 4 and 5). The left ilium articulated with the sacrum of the left side in the usual manner, with the exception of the intervention of a small spur of bone extending caudally from it. This has already been described. The crest of the right ilium was displaced cephalicly 1 em. and dorsally 4 JOHN SHELTON HORSLEY, JR. 3 mm. A small triangular piece of bone, 1.5 em. in length, articulated with the right deformed sacrum by a number of strong ligaments forming an amphiarthrosis (fig. 4 N). The crests of these lateral ilia were about 6 mm. further apart than they should have been if the right had its normal position and the two considered part of one pelvis. The right and left medial ilia were fused to form one bone which presented a dorsally protruding crest (fig. 4). This fused medial ilium was approximately a third the size of the normal lateral ilia. The vestigial right sacrum was fused with the base of the medial fused ilium. These two structures were contin- uous on the ventral surface, but dorsally there was a depression partially separating them. On the left the base of the fused ilium was joined to the third sacral vertebra by a synchondrosis, and with the first (proximal) caudal vertebra by a syndesmosis. This fusion of the ilia had brought the two medial acetabula so close together on the dorsal surface that they nearly touched each other (fig. 5). The long axis of this medially fused ilial ~ portion of the compound pelvis made a 15 degree angle with the midline on the right side. If considered as a dorsally interpolated pelvis, it would be about half the size of the larger pelvis. The two medial ischia formed a basin, which was open dorso- caudally and closed ventrocephalicly, presenting on each side the relatively high crests of the two medial tubera ischii. The basin measured 3.7 em. from crest to crest (fig. 5). In this basin lay the necks and proximal fourths of the femurs of the extra two legs, along with that portion of the heads that did not enter direetly into the hip-joints (fig. 4). The two obturator foramina opened ventrocephalicly through each side. They were com- pletely closed by thin ligamentous bands and were of about half the normal size. Caudal to the fusion of the medial ilia, and also to the acetabula, there was a very firm union between the right and left pelves along the whole length of the pubo-ischial symphysis of each (fig. 5). This line of fusion would eall for the same description whether the fused pelves were interpreted as right and left or dorsal and ventral components. SIX-LEGGED DOG oO The heads of the femurs of the extra two legs were about 1 mm. apart and articulated with the two medial acetabula, each form- ing an enarthrosis. The articulations were alike on both sides, and normal to the extent that they formed ball-and-socket joints, with synovial bursae, ligamentous capsules, ete. There was a slight twisting, however, produced by their abnormal positions. All of the structures that entered into these articu- lations were of approximately half the size of the corresponding structures of the normal right and left lateral hip-joint. The movements of these articulations were limited practically to a dorsoventral action due to the fusion of the tibiae of the two extra legs (fig. 3). The right and left lateral ischia were of normal size, but were slightly twisted laterally, the right more so than the left. The crest of the right lateral tuber ischii was 1 em. laterad of that of the right medial tuber ischii at the widest point (fig. 4). The right colon, vagina, and urethra united within the basin formed by these ischia into a cloaca (fig. 12). The opening of this basin was the pelvic mouth of the right pelvis. The corresponding crests of the left side were 2 cm. apart at their widest points and formed a somewhat less constricted basin for the left vagina. The aperture of this basin was the pelvic mouth of the left pel- vis (fig. 5). The bones of the right and left lateral legs were normal. Those of the extra two medial legs were very slightly shorter and slight- ly more slender than the lateral ones, as may be seen in figure 3. The tibiae of the supernumerary legs were fused medially along their whole extent. The fibulae appeared slightly larger than normal, the left fibula being more intimately fused with its tibia (fig. 3). No other marked abnormalities occurred in the bony structures. The double knee-joint was practically immobile except for a very slight action in the caudocephalic direction. Myology The muscles of the left lateral leg, thigh, and hip regions were normal; those of the right thigh also appeared normal except for a somewhat smaller size. 6 JOHN SHELTON HORSLEY, JR. In the hip region of the two extra legs there occurred only a very few small muscles that passed down to the thigh. These muscles were inserted along the proximal portions of the two femurs and seemed to represent only remnants. There was a . layer of superficial fascia over the whole of this muscle mass. Some atrophic vestigial muscles covered the popliteal fossae extending up over the distal two-thirds of the two femurs and down well over the ventral portion of the knee-joint. They were better developed on the left member than on the right. The space between the two femurs was occupied by an artery, a vein, a large nerve, and an abundance of loose connective tissue. The two legs of the extra pair were bound together by a superficial layer of fascia and the integument. There were two very distinct tendons of Achilles; the one of the left leg was more pronounced, and it was stretched so tight as to permit only very little movement of the left foot. The right foot was more free to move. The flexor digitorum brevis tendons were very distinct on the feet, but none of the muscles could be found. No muscles occurred beyond the extreme proximal ends of the fused tibiae; there was an enveloping layer of superficial fascia along their entire length. The ligamentum nuchae was the only abnormal structure ob- served cephalad of the diaphragm. This was a very thick, round ligament rather than, as usual, a thin ligamentous raphé. Splanchnology The stomach, small intestines, liver, gall-bladder, spleen, and pancreas were unpaired and apparently normal. The large intestines were double; one colon was very much distended and lay ventrad and to the right of a smaller colon (figs. 6, 7, and 8). The former had very short ascending and transverse portions, but a long descending portion which was constricted in the middle. This constriction produced two large sacculations, the caudal being the more distended. The wall of this portion was rigid and brittle, apparently lacking muscle constituents, This larger colon passed through the right pelvic SIX-LEGGED DOG 7 mouth and opened into the vagina of the right side, thus con- tributing to the formation of a cloaca. The smaller colon of the left side had neither teniae nor sacculations; and there were practically no corresponding ascending or transverse portions. It joined a normal rectum which ended in a normal anus; it was on the whole more nearly normal than the right colon. Feces were found in both colons, and there were no adhesions or con- strictions that could hinder either from functioning. The iliocolic portion of the small intestine was slightly enlarged, and at this point of enlargement the two colons anastomosed with each other and with the small intestine (fig. 6). Each colon had a caecum with an appendix. The right caecum was the larger and, excepting its increased size and its associated appendix, it seemed normal. This appendix was a constricted apical portion of about 1.5 em. in length (fig. 6). The left caecum was very short, being about 1 em. long. Its appendix had a smaller diameter than that of the right and was about three times as long (fig. 7). It was sharply folded at four dis- tinct points into a compact structure. The single ileocolic valve was relatively large and covered both colic orifices, but was thickened in that portion overlying the right orifice (fig. 8). Its opening was directed somewhat laterally and gave vent nearly directly into the left colon. Ata point immediately distal to the valve the lumens of the two colons united. On account of the thickening of one side of the valve, the connection between the lumens of the right colon and the small intestine was thrown to the left, somewhat toward the smaller colon. The caecocolic orifices of both colons were ap- parently normal (fig. 8). It may be of interest to note that there were ten persimmon seeds and a few whole grains of corn in the right colon. The great enlargement of the right colon may find its explanation in a gradual distention by fecal con- tents which could be only slowly voided due to lack of peristalsis following the paucity or lack of smooth muscle. On the right side the larger colon, the urethra, and the vagina had a common exit chamber, forming a cloaca (fig. 12). The right rectum formed the largest part of this chamber, and on 8 JOHN SHELTON HORSLEY, JR. this account the orifices of the vagina and the urethra seemed to empty into it at a point about 3 em. cephalad of the common ex- ternal opening, the vagina on the medial and the urethra on the lateral sides, respectively. The external genitalia of that side were slightly smaller than those of the left, but had a generally normal appearance. The urogenital system The single kidney was situated on the left side. No trace of even a vestigial kidney could be found on the opposite side. This lone kidney, located at the usual level, was considerably larger and more spheroidal than normal (fig. 9). It received a large renal vein from the left side of the inferior vena cava; and slightly dorsad and caudad of this point it received a renal ar- tery from the abdominal aorta. Midway between the latter and the pelvis of the kidney the renal artery divided into two, one entering dorsally and the other, after curving around the renal vein, entering ventrally and cephalicly to it. Before entering the pelvis the renal vein gave off a branch that coursed laterally over the ventrocaudal portion of the kidney to the left ovary and oviduct. A single large ureter passed caudally to empty into the left urinary bladder in a normal way (fig. 10). The minute anatomy of this kidney was perfectly normal. Cepha- lad of the kidney, and in their proper positions, occurred two adrenals (fig. 9). Of the two urinary bladders the left was apparently normal, except that it was slightly displaced to the left. The displace- ment was due chiefly to the presence of the greatly distended right colon. This bladder was completely collapsed. Its urethra was normal, emptying by means of the left vagina (fig, 10). The right urinary bladder was rigid and distended. It was composed of brittle tissue apparently like that of the larger colon. It was obviously smaller than the left bladder when the latter had become distended. At its cephalic end there was a narrow circular area (3 mm. in diameter) of very delicate tissue simu- lating a membrane, which yielded on the slightest pressure (fig. SIX-LEGGED DOG 9 11). There was no vestige of a ureter in connection with this bladder. Its urethra had about twice the normal diameter, and was composed of the same kind of brittle tissue as the blad- der. A medial longitudinal section of the bladder revealed a lining of elastic tissue that was hard to peel off and that had the macroscopic appearance and general consistency of a thin plate of cartilage. Irregular partitions extended from the walls form- ing two large pockets at the cephalic and caudal ends of the blad- der, respectively (fig. 11). Between these and in the central portion there were about ten smaller pockets. Along the entire ventral wall there was a space between this cartilage-like lining and the wall of the bladder which was continuous with the lumen of the urethra (fig. 11). The urethra had a very thick wall and emptied into the cloaca (fig. 12). The genital organs Two ovaries, each with its respective uterine tube (unpaired cornu uteri) leading to a respective uterus (corpus uteri), were situated in their normal positions. The ovary of the left side was flattened and oval in outline; that of the right side was flattened, elongated, and almost crescent-shaped, with a deep longitudinal groove extending over its lateroventral surface. The two uterine tubes extended caudomedially to their cor- responding uteri (figs. 12 and 13). The right tube was the shorter and slightly the thicker of the two. The right uterus was about twice as long and thick as the left. The latter presented no peculiarities in its continuation into the vagina of the left side. The right vagina was relatively short; it was continued into the common chamber which formed the cloaca. Both uteri were ab- normal to the extent that they were unicornuate. Four rows of asymmetrically distributed nipples, twelve in number, were present (fig. 14). 10 JOHN SHELTON HORSLEY, JR. Angiology The blood supply of the kidney has been described above. No traces of any blood-vessels that might have corresponded to the right renal artery and vein could be found. The abdominal aorta and the inferior vena cava remained single throughout their entire course, but they gave off extra branches which supplied the supernumerary structures. The distribution of these two chief vessels and their principal branches is shown in figure 15. The abdominal aorta gave off a right common iliac artery a short distance cephalad of its usual place of branching. The left common iliac was larger than the right and seemed to represent a direct continuation of the abdominal aorta. Its course was in direct line with that of the aorta to a point about 1 em. caudad of the point of branching of the right common iliac. Here there was a gentle curve to the left, the main portion being continued as the left external iliac which proceeded down the left lateral leg as the femoralartery. Slight- ly caudal to the beginning of this curve on the left common iliac just mentioned, and on the outside of it, a large branch came off which supplied the two extra legs. Very close to the origin of this larger branch there was a small branch which went to the left urinary bladder; while just caudal to this a larger one came off and divided into two, the medial representing the caudal (middle sacral) and going to the tail, the lateral going to the structures in the left pelvic cavity and probably representing the left internal iliac artery. One principal artery and one principal vein supplied the two extra legs. The plan of the arterial supply is represented in figure 16; that of the venous supply is practically indentical. The vessels continued their course caudally between the two femurs, giving off two small branches, one on each side, just distal to the heads of the femurs, to supply the scanty muscles and fascia of that region. No other branches were discernible cephalad of a level about 2 em. proximal to the knee-joint. At this point, however, both the artery and the vein divided into one medial and two lateral branches, the two lateral branches of SIX-LEGGED DOG 11 each vessel passing distally to the lateral sides of the fused tibiae and finally coming around on the dorsal side to form an anastomos- ing arch over the distal portion of the tibiae in the region of the ankle. From this arch sprang two main arteries and veins which passed on to supply the feet, the right set to the right foot and the left set to the left foot. Two medial smaller branches arose from the arch and supplied the structures in the immediate vicinity. The medial branch (fig. 16 ) of the principal vessels mentioned above represented a terminal branch. The medial artery and vein passed distally along the ventral line of fusion of the two tibiae where they became resolved into branches that supplied the structures of the ventral portion of the fused legs. The lateral branches supplied the structures of the lateral and dorsal surfaces. The venous system of the supernumerary legs paralleled the arterial system throughout its entire course. Numerous lymph nodes were found scattered throughout the abdomen. Just cephalad of the kidney occurred the two largest nodes. The smaller nodes were relatively more abundant along the inferior vena cava and the abdominal aorta. Those of the paired pelvic cavities were rather large and numerous. A large bean-shaped lymph node, about 1 em. in length, was situated at the level of the stifle-joint on the ventral side. This probably represented a composite popliteal node and was apparently the only lymph node of the two extra legs. Neurology A large nerve accompanied the principal artery and vein of the two extra legs. This nerve presented an oval cystic enlarge- ment, macroscopically suggestive of a ganglion, at the point where it entered the double leg, just distal to the heads of the two femurs. The nerve passed dorsal to the blood-vessels, ac- companying them as far as they went, and then accompany- ing the terminal or medial branch down over the midline of the double stifle-joint. As the nerve passed the latter point it pre- sented a gradual cone-shaped enlargement and, turning later- ally and dorsally around the medial condyle of the head of the 12 JOHN SHELTON HORSLEY, JR. right tibia, ended abruptly in the skin (fig. 16). On the external surface of the skin this termination presented a roughened scar- like appearance, the size of which was approximately that of the diameter of the nerve. Three smaller scar-like patches oc- curred below, and slightly medial to the principal one. No nerve fibers could be traced within the skin. The whole appear- ance of this nerve termination seems exactly what might have been expected if the nerve had penetrated the skin and its ex- ternal part had subsequently sloughed off, thus leaving a scar with the nerve firmly attached. The proximal part of this nerve was attached to the right wall of the cavity through which it coursed to the extra legs in company with the two main blood- vessels. This attachment was made by strands of tissue chiefly to the middle portion of the small opening. The portion of the nerve from the cyst forward consisted of a hollow, circular strand of tissue that tapered down almost to nothing. There remained no connection with the spinal cord. This nerve prob- ably represented fused right and left medial sciatic nerves. CONCLUSIONS Viewing the double portion of this dog, it is seen that the left component is more fully developed and that it is nearly in normal position, while the right component is entirely at the right of the median plane. The blood-vascular, the digestive, and the urogenital systems, excepting the kidney, and the fusions and articulations of the pelvic limbs, all consistently support an in- terpretation of this monster in terms of a side-to-side pelvic fusion of twin primordia, with complete resorption of the pre- diaphragmatic portions. A variant of this interpretation might be based upon the supposition that an original unpaired embry- onic dise suffered a caudal splitting to the point including the primordia of the pelves. It is not possible with the available data to decide finally between the suggested alternatives of fusion and splitting. However, the mixed character of the abdominal viscera (e.g., single kidney, double colon) seems to favor the interpretation of fusion rather than of splitting. The SIX-LEGGED DOG 13 one chief objection to the interpretation of lateral, as opposed to dorsoventral, fusion is the presence of the unpaired sciatic nerve of the extra two legs. It the interpretation of lateral fusion is accepted, then the compound sciatic nerve seems to be greatly displaced. The sciatic nerve normally passes through the pelvic mouth and then courses laterally over the acetabulum on down the leg. The sciatic nerve of the right and left lateral legs fol- lowed this normal course. ‘The fused sciatic nerves of the super- numerary limbs, however, entered the pair by a single root, having passed thither between the two medial acetabula, and not, as normally, through their respective pelvic mouths. The ap- parently ectopic position of the fused sciatic nerves can be ex- plained on the very probable supposition that the primordia of the originally paired medial sciatic nerves fused before the medial components of the pelves had developed beyond their blastemal stage. This explanation becomes the more plausible when it is recalled that the fused sciatic nerves had suffered degeneration at their proximal ends, due in all probability to pressure here following the further development and subsequent fusion of the two medial components of the right and left pelves. This dog belongs in the category of duplicate monsters desig- nated dipygus dibrachius tetrapus, and corresponds in general to the six-legged rat recently described by Conrow! and more closely to certain human monsters described under this desig- nation by Broman.? LITERATURE CITED 1 Conrow, Sara B. 1917 A six-legged rat. Anat. Rec., vol. 12, p. 365. 2 Broman, Ivar 1911 Normale und abnorme Entwicklung des Menschen. 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THE — >| ‘ ‘ ‘ ™ ‘ppl ae, Soe? apt B=) tng ey ee Dow => “<< S few teh de” ae a 7 ri + = * ye nw > » =a Ps a PLATE 2. ae \ é ng DESCRIPTION OF FIGURES 2and3 Roentgenogram by Dr. HP. ~ ope T'S s>* > ad » ~ n pi a > a Soy ; =< - * ; 16 SIX-LEGGED DOG PLATE 2 JOHN SHELTON HORSLEY, JR. 17 PLATE 3 DESCRIPTION OF FIGURES 4 Drawing of the double bony structures in the pe!vie region viewed from the right side. A, left medial femur; B, right medial femur; C, left medial tuber ischii; D, right medial tuber ischii; Z, right lateral tuber ischii; F, right lateral femur; G, left lateral femur; H, right lateral ilium; J, left lateral ilium; J, fused medial ilia; K, fifth lumbar vertebra; L, caudal vertebrae; M, right deformed sacrum; N, small piece of bone articulating with right deformed sacrum and right lateral ilium (possibly remnant of a second vertebral column). Four-fifths life size. Drawn by Helen Lorraine. 5 Drawing of the double bony structures in the pelvic region from a caudoven- tral aspect. A, left medial femur; B, right medial femur; C, mouth of right pelvis; D, central point of the fusion between the right and left pelves, which extends along the pubo-ischial symphysis of each; Z, left lateral obturator foramen; F, right lateral femur; G, left lateral femur; H, sixthlumbar vertebra. Four-fifths life size. Drawn by Helen Lorraine. SIX-LEGGED DOG PLATE 3 JOHN SHELTON HORSLEY, JR. ly PLATE 4 DESCRIPTION OF FIGURES colons from a right ventral aspect. The right caecum with its associa’ pendix is also shown. The portion of the right colon here shown represe only one of the two sacculations that were present. The second was appr « mately the same size. Four-fifths life size. Drawn by Helen Lorraine. 7 Drawing of the anastomosis of the small intestine with the right’ and colons from a left ventral aspect. The left caecum with its associated app en isalsoshown. Four-fifths life size. Drawn by Helen Loraine. SIX-LEGGED DOG PLATE 4 JOHN SHELTON HORSLEY, JR. it .caecutr ;- SEY EY Cs fa small rntestin Bs De com. pt.of anastomosis’ / 4 4 LE. colon —— $+ ti color es PLATE 5 DESCRIPTION OF FIGURES 8 Drawing of the ileocolie valve from the right side. The ileum and right colon are slit open longitudinally. Four-fifths life size. Drawn by Helen Lorraine. 9 Drawing of ventral view of kidney with its blood-supply, showing also the two adrenals. K, single kidney of left side; L and L’, left and right adrenals; U, single ureter leading to left urinary bladder; A, abdominal aorta; V, inferior vena cava; FR and FR’, renal vein and artery; P, phrenico-abdominal vein. Branch of renal vein to left ovary and uterine tube not shown in this drawing. Four- fifths life size. 10 Drawing of left urinary bladder partially distended. The bladder is in a position to show the ureter emptying on the dorsal surface. Four-fifths life size. 22 SLX-LEGGED DOG PLATE 5 JOHN SHELTON HORSLEY, JR. hi, caecum 23 PLATE 6 DESCRIPTION OF FIGURES 11 Drawing of the interior of the right urinary bladder from a dorsal aspect. It is slit open dorsally in the longitudinal plane. Four-fifths life size. Drawn by Helen Lorraine. 12 Drawing of the cloaca and genital organs of the right side. Cloaca is slit open. O, right ovary; Ut, right uterine tube (unpaired horn of right uterus) ; U, body of right uterus; Ur, urethra from right bladder; & and £’, orifices of uterus and urethra into common exit chamber forming the cloaca; C, right colon. Four-fifths life size. 13. Drawing of the genital organs of the left side. Vulva, vagina, and uterus (in part) are slit open. O, left ovary; Ut, left uterine tube; U, left uterus; EZ, external uterine orifice; H, hymen; E’, external urethral orifice; V, vulva; M, central projection of fold of mucous membrane which conceals the clitoris; F, fossa clitoridis; L, labia vulvae. Four-fifths life size. SIX-LEGGED DOG PLATE 6 JOHN SHELTON HORSLEY, JR. 25 PLATE 7 DESCRIPTION OF FIGURES 1! Diagram of the arrangement of the nipples. Each small black dot rep- resents a nipple. One-fifteenth life size. od ees pee 15 Diagrammatic drawing of the distal portion of the abdominal aorta and its branches seen from a ventral view. A, abdominal aorta; R.C.J., right common iliac; R.E.T., right external iliac; R.F., right femoral to right lateral leg; L.E.T., left external iliac; L.F., left femoral to left lateral leg; D.L., artery to extra pair of legs; C, caudal artery to the tail; a and a’, arteries to neighboring lymph nodes and other structures; b, artery to dorsal abdominal wall; c, artery to right colon; e and e’, arteries to structures in the right and middle portions of the pelvic cavity; f, artery to structures in the right portion of the pelvic cavity (probably right internal iliac); g, artery to left urinary bladder; h, artery to left ventral abdominal wall (probably left deep epigastric); 7, artery to structures of left pelvic cavity. By pelvie cavity above is meant that portion enclosed between the lateral components of both the right and left pelves. Veins accompanied the arteries. ; 16 Diagram of the arteries and nerve of the extra pair of legs as seen from a ventral view. The nerve ran immediately behind the main artery, but in the diagram it is shoved to the right. A, point of emergence of artery between the heads of the two femurs; C, cystic enlargement on the unpaired sciatic nerve; B,the curve of the sciatic nerve around the medial condyle of the right medial tibia; #, termination of the sciatic nerve in the skin; D, point about 2 cm. above proximal end of fusion of two medial tibiae; L, lateral branch which passed around the left medial leg (also level at which the sciatic nerve passed behind the stifle-joint); FR, lateral branch which curved around the right medial leg; M, medial branch which ran along dorsal line of fusion of the two medial tibiae; Ar, anastomosing arch on the dorsal surface of the fused medial tibiae in the region of the ankles, formed by the two lateral branches; F and F’, branches to right and left feet; m, small branches to the skin, fascia and scanty muscles; !. terminal branches of the medial branch supplying neighboring skin, fascia, and scanty muscles. Veins accompanied the arteries. SIX-LEGGED DOG PLATE 7 JOHN SHELTON HORSLEY, JR 27 Resumen por el autor, Howard B. Adelmann, Universidad Cornell, Ithaca. Un caso extremo de espina bifida con hernia dorsal en la ternera. El presente trabajo es una descripcién de un caso en el cual una porcién de la membrana mucosa intestinal emerge del cuerpo a través de un orificio situado en la regi6n lumbar de la columna vertebral. Este defecto es una consecuencia de un defecto en la linea primitiva. Translation by José F. Nonidez Cornell University Medical College, N. Y. AUTHOR'S ABSTRACT OF THIS PAPER ISSUED BY THE BIBLIOGRAPHIC SERVICE, MAY 10 AN EXTREME CASE OF SPINA BIFIDA WITH DORSAL HERNIA IN A CALF HOWARD B. ADELMANN Department of Histology and Embryology, Cornell University, Ithaca, New York TWO FIGURES The foetus forming the subject of this note is a part of the collection in obstetrics of the New York State Veterinary College and was submitted to me by Dr. B. F. Kingsbury for an expla- nation of the striking and unusual anomaly which it presents. I was unable to find an exactly similar case in the literature of teratology. The cases found in the literature which are to some extent analogous to the one about to be described are by Gurlt (77), who gives an account of a calf embryo with a lateral prolapse of the abdominal viscera through the spinal column; Veraguth (01) deseribed a human embryo with ectopia of the spleen and intestines. Finally, in 1917, Williams described a calf with the omasum and spleen extruded from an opening in the occiput. In all these cases the spinal defect is in or near the cervical region, while in the calf here described the defect occurs in the lumbar region. Unfortunately, the head and extremities of the specimen which I describe were removed before it was brought to the museum. The musculature was removed and only that part of the vertebral column and viscera shown in figure 1 remained. No clinical history of the case is available. The specimen under consideration is a nearly mature calf foetus which exhibits two well-marked defects: 1) an extreme degree of spina bifida and, 2) a well-marked dorsal hernia. The cleft in the spinal column is complete and involves the entire lumbar region. X-ray photographs show that the six 29 30 HOWARD B. ADELMANN lumbar vertebrae are affected and that halves of these arch around both sides of the defect, producing a somewhat triangular vertebral fissure, 7 cm. long and 3 em. wide at the cephalie end. However, the area of complete spina bifida extends for only 2 em. from the cephalic end of the defect; caudal to this point merely the vertebral arches are separated. ‘The vertebrae are more or less fused, especially in the cephalic end of the defect, where a bony prominence on the ventral side of the specimen gives evidence of this fusion. The tip of the transverse process of the sixth lumbar vertebra on’ the left side Fig. 1 Idealized sagittal section of foetus to show the relations of the intes- tines. C, caecum; D, dorsal opening of the intestinal pad; J, intestinal pad; 0, 08 coxae; R, rectum; S, blind sac; Sc, spinal cord; V, ventral opening of intes- tinal pad. lies under the innominate bone. The spinal cord is divided, the resulting halves passing around the defect. Nerves are given off on each side. A pad of intestinal mucous membrane protrudes through the opening in the spinal column. When sectioned, this pad proved to be mucous membrane of the large intestine. Two openings in the mucous membrane, one dorsal and one somewhat ventral, communicate with the large intestine (fig. 1). The dorsal open- ing is the larger and communicates with a small portion of the large intestine posterior to the caecum and with a blind pouch which also proved to be a portion of the large intestine when SPINA BIFIDA WITH DORSAL HERNIA IN A CALF il examined under the microscope. ‘lhe remainder of the large intestine, that is, the portion extending from the anus to the pad, ends in a small opening on the ventral side of the caudal end of the pad. Fig. 2 Dorsal view of the defect, showing the relations of the intestinal pad. D, dorsal opening of the intestinal pad; 7, intestinal pad; O, os coxae; R, rib; 7, transverse process of lumbar vertebra; V, vertebral column. The literature dealing with the causes of spina bifida is most extensive and the theories advanced are numerous. The theories of maternal impressions and amniotic adhesions need only be mentioned here. The first has long been discarded and the latter theory has also been looked upon as invalid. Gurlt (77), THE ANATOMICAL RECORD, VOL. 19, NO. 1 32 HOWARD B, ADELMANN in assigning a cause for the condition which he describes, men- tions the adhesions of the membranes caused by tearing due to turning of the foetus. This is a rather vague explanation at best. Modern investigators would more likely agree with Mall, who says: “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.” Of more importance, it seems to me, are the theories which regard a disturbance of growth metabolism as the causative factor in producing abnormalities. The experiments of Hertwig, Morgan, Stockard, and others may be briefly mentioned. In 1892 Hertwig published his classical essay on ‘Urmund und Spina Bifida,” in which he showed that spina bifida could be produced by the action of morphine. Morgan, in 1894, produced spina bifida by adding 0.6 per cent sodium chloride to the water in which eggs were developing. Hertwig, in 1896, found that salt solutions stronger than 0.6 per cent retarded development and the eggs died without going beyond the gastrula stage. Similar results were obtained by Hertwig and Morgan by raising the temperature of the water. Godlewski ('97, ’00, ’01) and Samassa (96, ’98) found that spina bifida could be produced through lack of oxygen. This might easily be the case in faulty implantation. Baldwin ('15) was able to produce spina bifida in almost every instance by treating the yolk portion of the egg with violet rays. The action of the ultra rays, by destroying a portion of the yolk hemisphere, results in an upset of the balance between the differentiation of the neural canal and the approximation of the blastoporic lips. The differentiation is not retarded, and the half tubes differentiate into two tubes before the lips of the blastopore close. In the present instance, the defect unquestionably arose very early in the development of the individual and is essentially the same as those produced by Hertwig, in whose experiments spina bifida or ‘ring’ embryos resulted from incomplete approximation of the blastoporie lips. SPINA BIFIDA WITH DORSAL HERNIA IN A CALF 33 There is no evidence that gastrulation in the calf is accom- plished by means of blastoporic lips, but we may regard the primitive streak as homologous with the blastoporic lips, since both give rise to spinal cord, notochord, and mesoderm. The opening, in this instance, may be a secondary condition which has arisen in the region of the potential neurenteric canal, the persistence of which has been recorded in numerous instances. The failure of the blastoporic lips (primitive streak) to approxi- mate closely, differentiation, however, not being retarded, results in an opening bounded by material which becomes spinal cord, notochord, mesoderm, and perhaps a small amount of entoderm. In any case, however, the latter would adhere to the edges of the opening forming a passageway into the primitive digestive cavity which may or may not coincide with the position of the potential neurenteric canal. Veraguth (’01) regards the open neurenteric canal as the cause of the anomaly which he describes. The dorsal hernia which occurs in this specimen may be interpreted thus: There is a gap in the dorsal wall of the intestine at the primitive streak, and the ventral wall pushing up through the gap has produced a pad of mucous membrane such as here found. I regard the blind sac as an outpocketing caused by a fold in the intestinal wall. The steps in the formation of this dorsal hernia may be easily understood by consulting a series of figures given by Cullen in “The Umbilicus and its Diseases,” page 224. ; It is interesting to note that spina bifida always occurs high up or low down in the spinal axis and to speculate why the defect should be so restricted. Lebedeff’s (’81) theory that the curva- tures of the spinal axis disturb the normal development of the medullary tube seems to be invalidated by two facts: 1) the neural folds have already closed before the body acquires its normal curvatures and, 2) the cervical flexure is most pronounced, whereas spina bifida is most frequent in the lumbar region. In conclusion, I wish to thank Professor B. F. Kingsbury for many helpful suggestions; Professor W. L. Williams, who loaned the specimen for description, and Mr. R. R. Humphrey, who made the drawings. 34 HOWARD B, ADELMANN BIBLIOGRAPHY Banbdwin, F. M. 1915 The action of ultra-violet rays upon the frog’s egg. Anat. Ree., vol. 9, p. 365. Batuantyne, J. W. 1897 Teratogenesis: An enquiry into the causes of mon- strosities. Oliver & Boyd, Edinburgh. Broman, Il. 1911 Normale und abnorme Entwickelung des Menschen. Verlag von J. F. Bergmann, Wiesbaden. Couten, T. 8S. 1916 The umbilicus and its diseases. W. B. Saunders Co., Philadelphia. Goptewsk1, BE. 1901 Die Einwirkung des Sauerstoffes auf die Entwickelung von Rana temporaria. Arch. Ent. Mech., Bd. 11. Goop, J, P. 1912 Spina bifida in the neck region of a ferret embryo 8 mm. long. Journ. Anat. and Phys., vol. 46, p. 391. Guru, BE. F. 1877 Ueber thierische Missgeburten. Verlag von A. Hirschwald, Berlin. Herrwic, O. 1892 Urmund und Spina bifida. Arch. mikr. Anat., Bd. 39, S. 866. Kermavuner, F. 1909 Missbildungen des Rumpfes. In E. Schwalbe, Morph. der Missbildungen, III teil, I. Lieferung, I. Abt., 3 Kap., 8. 86. Kerner, F., ann Maui, F. P. 1910 Human embryology. J. B. Lippincott Co., Philadelphia. Leseperr, A. 1881 Ueber die Nntstehung der Anencephalie und Spina bifida bei Végeln und Menschen. Arch. path. Anat., Bd. 86. Linus, F., anp KNowtron, F. P. 1897 On the effect of temperature on the development of animals. Zool. Bull., vol. 1, p. 179. Maui, F. P. 1908 A study of the causes underlying the origin of human mon- sters. Jour. Morph., vol. 19, p. 3. Morean, T. H. 1897 The development of the frog’s egg. Macmillan & Co., New York. 1902-1905 Several papers in Arch. Ent. Mech., Bd. 15, 16, 18, 19. Srockarp, C. R. 1906 The development of Fundulus heteroclitus in solutions of lithium ehlorid, with appendix on its development in fresh water. Jour. Exp. Zoél., vol. 3. 1907 The artificial production of a single median eye in the fish embryo by means of sea-water solutions of magnesium chlorid. Arch. Ent. Mech., Bd. 23. Veracutu, O. 1901 Ueber nieder differenzirte Missbildungen des Central- nervensystems. Arch. Ent. Mech., Bd. 12. Wueeter, T. 1918 Study of a human Spina bifida monster with encephaloceles and other abnormalities, Contributions to Embryology, no. 22, vol. 7. Carnegie Institute of Washington. Witiiams, W.L. 1917 Veterinary obstetrics. Published by the author, Ithaca, N.Y. ' ae f » 2 4 = } er Wy ae » &s ~S - f » % : ° fae a ca e i “a fe - - ric Vi cs Resumen por el autor, R. M. Strong. Escuela de Medicina de la Universidad Loyola, Chicago. Sobre un modelo econédmico de los principales tractos de la médula espinal y tallo cerebral. Este modelo incluye dibujos de secciones transversales (au- mentadas ocho didimetros) practicadas en cuatro niveles de la médula y en siete niveles del eje cerebral, montadas sobre un tablero de diez piés de longitud y un pié de anchura. Para representar los tractos mas importantes se emplean cintas eoloreadas. El problema de indicar el trayecto de los tractos entre el tallo cerebral y el cerebelo se resolvié colocando un arco sobre la regién del puente. En este arco se insertan los tractos con conexiones cerebelosas, representados por cordones color- eados. Los materiales empleados en este modelo suponen un gasto minimo. Este modelo ha sido usado con gran provecho por varias clases, siendo especialmente util para la obtenci6én de conceptos sobre la proyeccién de los tractos. Translation by José F. Nonidez Cornell University Medical College, N.Y. AUTHOR'S ABSTRACT OF THIS PAPER ISSUED BY THE BIBLIOGRAPHIC SERVICE, MAY 10 AN INEXPENSIVE MODEL OF THE PRINCIPAL SPINAL CORD AND BRAIN STEM TRACTS R. M. STRONG Department of Anatomy, Loyola University School of Medicine TWO FIGURES The apparatus described here has been useful in helping my students in the difficult work of learning the tracts of the cord and the brain stem. It is especially helpful in getting projec- tion conceptions, and it involves little expense. Drawings with a magnification of eight diameters were made for four levels of the cord and seven levels of the brain stem, the last being through the diencephalon. These drawings were made on light bond typewriter paper, and they were pasted on light binding board to produce what will be termed sections in this paper. In order to have the structure outlined visible on both faces of each section, a reverse copy of each drawing was made. This was accomplished by tracing the second drawing for each section on a piece of paper which was held against the back of the sheet of paper bearing the drawing. The two sheets were placed against a window pane with the first drawing against the glass. With sunlight transmitted through the two sheets, it was easy to make the tracing. The pictures can of course be made by photography or with the aid of a projection outfit. A pantograph can also be used to advantage in getting a desirable size for the drawings. A board 10 feet long and 12 inches wide was used as a base; it was stained and varnished. ‘The sections were mounted on the board by means of strips of galvanized sheet iron (figs. 1 and 2) These strips were cut 13 inches wide by 43 inches long. Each strip was bent so that two limbs making a right angle with each other resulted. One of these limbs, 31 inches long, was fastened 35 36 R. M. STRONG to the board by screws. The other limb, 1} inches high, has a vertical position. Two pairs were used for each section, and they were mounted so that the vertical limbs had just enough space between them to insert the base of a section with a tight fit. Before mounting, holes were made in the horizontal limbs for the screws used in fastening them to the board. It was not found necessary to fasten the vertical limbs to the sections as the tight fit and the strings employed in the model hold the sections in place. There is a tendency for the sections to be pulled away from a vertical position by the taut strings. This difficulty was met by using a piece of white string as a stay line. It was attached to the top of each section at its middle and was tied at the ends of the board, after being made taut. Colored strings were used to indicate tracts, and they were fastened at their ends to nails. A tract not extending the whole length of the cord, for instance, is represented by a string which was deflected beyond its last level in the model to a nail at one side. Descending tracts are represented by red strings, exterocep- tive by blue, proprioceptive by yellow, and association tracts by purple. The colors fade eventually and become dull from soiling, in which case it is a very simple process to substitute new strings for the old. The regions occupied by the tracts are indicated diagrammatically with corresponding colors in the drawings. The cerebellum presented a perplexing problem in construct- ing the model. This was finally solved by placing an. arch as seen in figure 1 over the pons region. Tracts passing through the restiform body, brachium pontis, and brachium conjunc- tivum are represented by strings which have the cerebellar ends attached at the top of the arch. Decussations are represented in the drawings by the usual methods (fig. 2). In the case of the strings, the problem was solved by passing the string across the face of a section in the region of the decussation in question. The section is perforated three times by each string in such cases instead of once. The SL SS MODEL OF SPINAL CORD AND BRAIN STEM TRACTS Fig. 1 View of entire model Fig. 2 View showing region of fillet and pyramid decussations 38 R. M. STRONG string goes through the section before decussation back again through a second aperture and then a third time through after decussation. The same procedure was followed for the string representing the tract of the other side, and the two strings cross each other in the median plane. Apertures in the sections were made with a steel punch be- fore mounting on the base board. The’ strings were passed through the apertures with the aid of a large darning needle. This model is large enough to permit a number of students to study it simultaneously and it is in almost constant use dur- ing laboratory periods. I have not labeled any part of it, as I prefer to have the students identify the structures represented. A limited amount of assistance in interpreting the model is given. 2) 3% .~ Resumen por el autor, Jacob Reighard. Departamento de Zoologia, Universidad de Michigan. FE] almacenamiento y manejo de cuadros murales. En vez de los listones de madera que se usan ordinariamente, el autor emplea listones de madera “basswood” tenidos con ereosota. Las dimensiones de estos listones son } de pulgada de espesor por } de pulgada de anchura. Se clavan estos listones a los cuadros empleando clavos de alambre de } pulgada de diimetro, y debajo de las cabezas de dichos clavos se perforan cuadrados de hierro galvanizado del num; 28. Los listones ocupan la superficie anterior de cada cuadro y los clavos se clavan en los lados libres. Cada list6n superior lleva un gancho Hodge atornillado en el centro del list6n. Cuando se hace girar al gancho de modo que venga a coincidir con el plano de la limina, sirve para colgar esta tltima de una barra de hierro colocada en el cuarto en donde se guarden las laminas. De este modo éstas se conservan sin arrugas, y puesto que los listones ocupan muy poco espacio, pueden colgarse todas ellas de un modo semejante al de las hojas de un libro suspendido por el lomo. Las kiminas se arreglan en orden de materias por medio de ntimeros, como si se tratase de un catdlogo de materias, y cualquiera de ellas puede ficilmente sacarse y volverla a su sitio. Cuando se necesita usar una de las liminas se hace girar el gancho 90 grados, y entonces puede colgarse de un bastidor, alambre o cualquier otro soporte en la clase. Algunos de los mecanismos descritos han venido usindose hace largo tiempo; otros son nuevos. Sirven para coleecionar liminas de todos los tamafios en un espacio mfnimo y para poderlas guardar en orden y emplearlas invirtiendo el menor tiempo posible. El presente trabajo indica donde pueden obtenerse los materiales empleados y su coste. Translation by José F. Nonidez Cornell University Medical College, N.Y. AUTHOR'S ABSTRACT OF THIS PAPER ISSUED BY THE BIBLIOGRAPHIC SERVICE, MAY 10 THE STORAGE AND HANDLING OF WALL CHARTS JACOB REIGHARD Department of Zoology, University of Michigan FOUR FIGURES The maker usually supplies charts with wood rods tacked and glued to the ends. In use they are hung from hooks on the wall of the lecture room by means of two metal rings tacked to the upper rod. When stored they are rolled and tied about with tapes. In the Zoology Laboratory of the University of Michigan we have tried probably every known device for the storage of rolled charts. ‘They may be piled on racks such as once were used at Harvard University. To make these, pieces of round iron, some 30 inches long or more, are bent for a couple of inches at the ends, flattened and drilled at the middle, and screwed horizontally to wooden uprights to as to project on both sides like large coat hooks and form two ladder-like sets of supports. On two such uprights, properly spaced, one may store many charts and classify them roughly. The uprights may be built on a base with casters beneath it and the whole contrivance wheeled from place to place. Labels may be written on discs of cardboard tacked to the ends of the chart rollers. As the charts accumulate and are piled several deep on each support, it is impossible to keep them in order and much time is wasted in locating and reading the small labels. In spite of the most ingenious labeling it is often necessary to unroll the charts to find those that are suitable, and this entails not only loss of time, but damage to the charts. To find the charts more readily, we have tried supporting them on pairs of large iron hooks screwed into vertical wood strips nailed to the walls of the lecture room. The charts then lie in one plane like the rungs of numerous ladders set against the wall. They may be classified and labels put beneath the groups. But 39 40 JACOB REIGHARD as the collection grows it takes much wall space. It may be- come necessary to climb to reach the uppermost charts and they have still to be unrolled. In place of supporting the rolled charts on metal rods, one may use deep wood frames divided into compartments like the boxes in a post office. These may be arranged to hold the charts in vertical or horizontal position, but we have found this plan as cumbersome and wasteful of time as the other. Home-made charts accumulate in every laboratory and are apt to be of various sizes and of material that deteriorates if kept rolled and frequently unrolled. To avoid the labor of at- taching them to rollers, one is tempted to let them lie flat, and we have piled them thus in large cases with numerous close-set shelves on which they may be roughly classified. It is not easy to label such charts so as to find readily what is wanted, and in pulling one from a pile for examination it is likely to be torn or damaged by rubbing. ‘To return it to its proper place the whole pile must be taken out. Naturally one puts the chart back on top of its pile or on top of some other pile and the whole collec- tion is thrown into confusion. In addition to this, if some charts are kept flat and others rolled, there are two places to look and time is wasted in the search. In hanging the charts for use the two rings at the top must be put over hooks on the wall of the lecture room. To accommo- date the unequal spacing of the suspension rings of different charts, the hooks must be movable. One may suspend picture hooks from a molding or wire and slip them along until the sus- pension rings of the chart will go over them and one must climb a ladder to do it. One may dispense with the ladder by using a wooden frame filled with wire netting and arranged to be raised and lowered by ropes and pulleys. The picture hooks may be stuck into the lowered netting at suitable intervals, the chart rings slipped over them, and the whole thing hoisted, or one may cover the hoistable frames with cotton cloth and pin or clip his charts to that. After trying most of the plans outlined, we sought a means of keeping all charts in a minimum space in one collection with- STORAGE AND HANDLING OF WALL CHARTS 4] out rolling them and so that they could be classified and exam- ined and each removed and returned without disturbing the rest. We sought also the easiest way of hanging them for use. The result combines the unpublished devices of friends with some of my own. The universities in which I have seen some of these devices in use are indicated in parenthesis. I do not know that any other consistent scheme has been described in print. We now store all our charts together by hanging them from a piece of 3-inch iron pipe supported from the ceiling by a wire and stayed by wire to the side wall (Wisconsin). They are in a small room reserved for the purpose. The charts hang flat, one against another, like the leaves of a book. Because the wooden rods take too much room, we have removed them and have sub- stituted thin strips of basswood (fig. 4, chart at right.) A thous- and of these 1 x 3 inches by 40 inches, cut at a planing mill, now costs $18.00. Probably any good soft wood would answer, but hardwood warps so that the strips do not stay flat. The strips are stained brown by dipping in creosote. They are tacked to the face of the chart along its ends by means of 3- inch wire tacks or clout-nails set from 4 to 6 inches apart and clinched on the free face of the strips. To keep the heads of the nails from tearing through the charts we have put under each a piece of 28-gauge galvanized iron. This is 3 inch square, perforated at the center, and has the corners turned with pliers to as to form small points that penetrate the chart and go a lit- tle way into the wood. We find it better not to use glue, and none of our charts attached to the strips by tacks in the manner described has yet come loose from its supports. A piece of sheet iron 2 x 2 feet now costs fifty cents, and from it about 1000 squares can be made in the laboratory. For suspending the charts we use the hook devised by Prof. C. F. Hodge. It is screwed into the upper strip at such a point as to make the chart hang level. When the hook is turned into the plane of the chart it serves to suspend it from its support in the chart room as a suit of clothes is hung from a rail (fig. 1). When the chart is to be used, the hook is turned through 90 degrees and may then be slipped over a picture molding, wire, or other 42 JACOB REIGHARD STORAGE AND HANDLING OF WALL CHARTS 43 support in the lecture room. To hoist it into place and get it down again, we use a light wood pole 63 feet long, also Profes- sor Hodge’s device. At one end the pole is provided with a ferrule through which is driven the sharpened end of a piece of 8-inch round-iron. This is bent as shown in figure 3 and has its free end slotted to form a pair of claws like those on a tack- hammer. The hump on the suspension hook fits between the Fig. 2 The Hodge hook. See text Fig. 3 Pole for putting up and taking down charts. For description, see text claws on the pole and permits the chart to be handled without waste of time. In each lecture room a short suspension rod is provided. To this the charts are transferred after use and from it an assistant collects them from time to time and returns them to the chart room. The Hodge hooks were obtained from the Wire Goods Co., Worcester, Massachusetts, and cost, before the war, $1.35 per gross. The iron claw may be made by any black- smith. THE ANATOMICAL RECORD, VOL. 19, No. | 44 JACOB REIGHARD For displaying charts in the lecture room we have used a modi- fied form of a device made for displaying buggy robes, and used for charts at the University of Wisconsin. As used by us, this device consists of eighteen wood arms, each supported by an iron rod, and arranged to swing like the arm of a derrick (fig. 4). The arms are pivoted to steel sectors which turn on the central upright axis. By turning the sectors all the arms may be thrown either to right or left. Each arm supports two charts back to back. Any one of these may be brought into view by turning the arms as one turns the leaves of a book held vertically. The device may be attached to the wall, as ours is, or carried on a movable base resting on the floor. It may be obtained from John Best, Galva, Illinois, and cost (in 1915) $19.00. The whole arrangement has proved very satisfactory. The charts are designated by the numbers of the Concilium Biblio- graphicum gummed to the upper wood strip (fig. 4). They are arranged on the rail in systematic order, and any one may be located, removed, inspected, and returned to its place without difficulty. To subdivide them, index labels are hung at inter- vals (fig. 1). These are wood strips suspended from the rail by Hodge hooks. ‘They project beyond the charts at one end and each bears at that end a square of chart cloth with an ap- propriate label and at the opposite end a thin bag of sand to bal- ance it. Charts of any ordinary size may be accommodated. Very large maps may have to be kept rolled in a separate place, but they may be represented in the chart collection by appro- priate dummies on which are written references to their location and to which may be attached photographs of them. Our col- lection consists now of 310 charts varying in size from 2 x 2 feet to 5} x 8 feet and made of various materials. These occupy in storage a space 11 feet long, but the same space will probably accommodate nearly twice as many and still permit anyone to be examined in situ. If longer hooks were used the charts could be hung alternately high and low from parallel supports so that the wood strips would not be opposite. The same space would then accommodate many more, WALL CHARTS OF HANDLING E AND ‘ x STORAC yo Jo] [burs oULL ‘S1o[[O1 Pooma “4xo} 90S ¢ ‘sdta }s pc HOLLYPOISH, EQaourepuey o a’ ‘drys aaddn JOMSSBG OI} 46 JACOB REIGHARD As our collection grows we shall make a card catalogue of the charts in which each chart will be represented by small photo- graphs (Pennsylvania). By attaching concilium numbers to the duplicate photographs and arranging them according to the con- cilium system, cross references will be made to many of the charts. Thus the chart shown at the right in figure 4 would be repre- sented in the catalogue by several photographie cards, each of which would bear an identical number to show the location of the charts in the collection. These cards would bear also dis- tinetive concilium numbers by which they would be placed in the catalogue under crustacea, embryology, and under one or more anatomical designations. a Gs ‘ io - am - he Mildiobe, ws, aed! al ' i a 5 einen 2s Dabs: Hi } (bee pt a ri i ™% RATeRTE. avidly < ol) mouletEN » eb earth is! m8 aires fh! i Cur Ghali) wy: Gp * pret ow ii seus (Shy . ee ee i pallivrene Se ii CLL oe 4, ab eMIM) Sal CGR Wek 54 Lh oy Resumen por el autor, Roy Lee Moodie, Departamento de Anatomfa, Universidad de Illinois. La naturaleza del sistema Haversiano primitivo. Los huesos mas antiguos, encontrados en el Silirico y el Devénico, carecen de verdaderos sistemas Haversianos, que se desarrollan primeramente con cierta extensién en Dinichthys, del Devénico. En este pez acorazado alecanzan el méximo de desarrollo en conexién con el proceso dentario de la maxila y premaxila. Las lagunas participan de la. naturaleza de los odontoblastos; los canalfeulos nunea comunican entre sf; la laminilla fibrilar existe; las fibras perforantes no se han desar- rollado; el canal central es ancho. El polarfscopio es util para distinguir la naturaleza de los sistemas Haverfsanos primitivos. No existen pruebas sobre la evolucién de la estructura del hueso; se percibe un cambio bastante brusco con la introduccién de~ las formas de mamfferos. ; Translation by José F. Nonidez Cornell University Medical College, N.Y. AUTHOR'S ABSTRACT OF THIS PAPER ISSUED BY THE BIBLIOGRAPHIC SERVICE, MAY 10 THE NATURE OF THE PRIMITIVE HAVERSIAN SYSTEM ROY L. MOODIE Department of Anatomy, University of Illinois, Chicago ONE PLATE (THREE FIGURES) The term Haversian system is necessarily of very general sig- nificance and is used in a broad way to distinguish any concentric arrangement of osseous lamellae around a central canal. It is often difficult to distinguish between a dentinal system, that is, a concentric arrangement of dentine, around a dentinal tubule and a true Haversian system.as seen in long bones, since the two often grade into one another. The presence of lacunae does not seem to be essential to an Haversian system, though they usually are present. In the fishes, both modern and ancient, osteoid tissue, largely lacking lacunae, may arrange itself around a vas- cular opening and thus have all the appearances of an Haversian system, and give the same orthorhombic light reactions under polarized light. _The type of such a system may be taken as those most highly specialized Haversian arrangements seen in the long bones of man, especially in the femur. From this complete system down to a slight lamellar arrangement of substances one may find all gradations in a series of fossil bones representing the history of the vertebrates from the Devonian to the Pleistocene. Such a review has been made, and it will doubtless be of interest to de- scribe and illustrate the most ancient Haversian system of which we have any knowledge. There is no apparent indication of a gradual evolution in form of the Haversian system from the most ancient vertebrates to modern mammals, although there is a gradual development in the form of the lacunae and canaliculi. The reptiles do not 47 48 ROY L. MOODIE show a higher type of Haversian system than do the amphibians or fishes, as they do in their skeletal organization. Haversian systems in dinosaurs are as primitive as they are in Devonian fishes. They seem to have sprung into existence full formed without undergoing the process of evolution such as has obtained in the bodily organization of the vertebrates. The most ancient organization of osseous elements which sim- ulate an Haversian system are to be found in the dental process of the premaxilla of a Devonian arthrodire, Dinichthys (figs. A and B), allied by some paleontologists with the lung fishes. This arrangement is well known to paleontologists and has been described by Claypole (94). These curious structures are not present in other portions of the armor of Dinichthys and are to be regarded as specialized dentinal systems, though not found in the true teeth which are not connected with the cranial skele- ton. The Haversian canal resembles a dentinal tubule, the the lacunae are those seen in the cementum of modern fishes, the lamellae are fibrillar and partake of the characteristics of dentine as seen in the teeth (fig. C) of Carboniferous sharks, the interlamellar space is filled with cement and there are true inter- stitial lamellae, though never any of the type due to the partial absorption of other Haversian systems. I have not seen this type, known as false interstitial lamellae in any fossil verte- brate. The orthorhombic light reaction under polarized light is exactly like that of the highly specialized Haversian systems in the femur of man. The canaliculi from the lacunae communi- cate neither with each other nor with the central canal, nor do they do so in any fossil vertebrate below the mammals. The lacunae are not confined largely to the interlamellar spaces, as they are in mammals, nor is there any apparent plan in their arrangement. Often, as in a Permian reptile, one finds three lacunae grouped together, surrounded on all sides by wide areas of osteoid tissue lacking lacunae. The use of polarized light is essential to an adequate under- standing of the structure of fossil bone, since usually under pol- arization, lamellae, fibrillae, canaliculi, and other minute his- tological units, invisible under ordinary light, stand out with —— NATURE OF PRIMITIVE HAVERSIAN SYSTEM 49 startling distinctness. The importance of this has been com- mented upon by various authors in their studies on the histo- logy of fossil structures. Arey (‘19) has recently called attention to the presence of Haversian systems in the membrane bones of man. The sys- tems he described and figured, however, cannot be called true Haversian systems, but resemble those seen in fossil reptiles. It is interesting to note in the temporal bone of an Oligocene mammal an arrangement of substances exactly similar to those described by Arey for man. These intermediate or pseudo- Haversian systems often fail to give an orthorhombic light re- action, as they do in the case of the Oligocene mammal. The difference between the true and the intermediate types of sys- tems is to be found in the absence of intercommunications of the canaliculi with either the central canal or other lacunae and in the occasional failure to secure the same light reactions. In all other respects they are similar. The review was undertaken with the idea of gaining a con- ception of tissue organization in ancient vertebrates so that I might judge as to the disturbing effects of pathological processes upon the structure of the part. The presence of osteoid tissue in ancient vertebrates is a normal condition. Kolliker (‘57) noted that many fish bones are composed entirely of osteoid tissue. One interesting effect in pathological conditions of fos- sil bone is to stimulate the growth of pseudo-Haversian systems, and to increase the vascularity of the bone. The same fact has been noted by Foote (‘16) in the fractured femur of a frog, where Haversian systems are ordinarily absent. SUMMARY Primitive Haversian systems of the very ancient vertebrates differ but slightly from highly developed systems of modern mammals and have been but slightly modified by the passage of time. Each group of vertebrates has its own type of lacunae, but the organization of the Haversian systems remains the same. The concentric arrangement of lamellae is not an incident of 50 ROY L. MOODIE evolution, but a response to the mechanical laws of organiza tion of the part. True Haversian systems are confined to the mammals. q A more complete account and more adequate illustrations will be found in the Williston Memorial Volume now in preparation. BIBLIOGRAPHY e Arey, L. B. 1919 On the presence of Haversian systems in membrane bones. Anat. Rec., vol. 17, pp. 59-62. Crayro.te, E. W. 1894 Structure of the bone of Dinichthys. Proc. A Mieros. Soc., vol. 15, pt. 3, pp. 189-191, figs. ; Foore, J. S. 1916 Comparative histology of the femur. Smithson. Contrib. to Knowledge, vol. 35, no. 3. KGLuikeR, A. 1857 On the different types in the microscopic eabingbeae the skeleton of osseous fishes. Proc. Roy. Soc. London, 1857, pp. 656-668. i - PLATE 1 EXPLANATION OF FIGURES A A field in a section of the premaxilla of Dinichthys, a Devonian Arthrod od. e, showing the distribution of the oldest known representatives of the Haversi: systems. Between adjacent systems are to be seen interstitial lamellae. systems, at the lower left-hand corner show the concentric lamellae. X70 — B A single system showing large size of central canal, concentric lame distribution of lacunae and nature of ground substance, whieh 1 under pols light is seen to be fibrillar. The blatk band at the left lower corner i isa fossilization crack and has no significance in the histology. C Dentinal tubules of Mazodus, a carboniferous shark, the speciatized systems in Dinichthys above. 70. ROY kL. MOODIE 4 ; Resumen por el autor, Hubert Sheppard, Departamento de Anatomfa, Universidad de Kansas. Hermafroditismo en el Hombre. En el hombre, el hermafroditismo con existencia de testfculos y ovarios normalmente desarrollados en el mismo individuo aparece raras veces. En el individuo descrito en el presente trabajo los testiculos aparecfan en el escroto y los ovarios en la cavidad pélvica. El tejido que formaba ambos 6rganos era normal en estruetura en todos sus detalles. Se podfa distinguir perfectamente una pared muscular uterina que limitaba una cavidad que desembocaba en la vagina. Las ttinicas del conducto deferente y el oviducto, asi como sus cavidades podian también distinguirse. El cuello del titero ocupaba casi exactamente la posicién del utriculo prostidtico del var6én. En todos los casos de hermafroditismo se ha podido comprobar una distincién mareada entre los tejidos genitales masculino y femenino, sin encontrarse nunca una mezcla indefinida de ambos elementos (es decir, un verdadero ovotestfeulo). En el raro caso descrito encontramos el mismo fenédmeno con una separacién aun mayor de las dos clases de tejido, puesto que los testfeulos y ovarios ocupaban su posicién normal correspondiente. Translation by José F. Nonidez Cornell University Medical College, N. Y. AUTHOR'S ABSTRACT OF THIS PAPER ISSUED BY THE BIBLIOGRAPHIC SERVICE, MAY 10 HERMAPHRODITISM IN MAN HUBERT SHEPPARD Department of Anatomy, The University of Kansas SEVEN FIGURES An opportunity to make a study of the anatomical structures of the genital organs of hermaphroditism in man is seldom found for two reasons: first, such irregularities seldom occur and, sec- ond, when they do occur the material is exceedingly difficult to obtain for laboratory purposes. As recently as 1911 it was as- serted that ‘hermaphroditism in the sense that separate testicles and ovaries are found has not been demonstrated in man, nor even in other mammals beyond a doubt.”” We thought it worth while, in the light of this and other investigations, to report a study of the anatomical structures of an extreme case of her- maphroditism which came to the dissecting room. The gross study is supplemented by microscopical examinations in so far as the condition of the material would permit. The cadaver featured, objectively, both as a male and as a female subject. Hair was lacking on the face and scant around the genitals, the body was large and obese, with the mammae well developed, large and flabby, which in every way resembled a female rather than a male organ. One would have judged, in so far as the external genitals were concerned, that they were male rather than female genitalia. However, upon a closer examination, one could see that there were certain irregularities. The penis was small with a dilated urethral orifice three-fourths as large as the organ itself (fig. 1). The scrotum appeared to be abnormally large, although the testicles, upon palpation, were found to be normal and symmetrically formed. When the region posterior and beneath the scrotum was palpated, its ap- parent unusual size was found to be due to a large fold or ridge which extended from near the anus to the pubis on either side of the penis. 56 HUBERT SHEPPARD THE FEMALE EXTERNAL GENITALIA After the skin and scrotum were completely reflected from the urogenital triangle, the large ridge beneath the scrotum was found to be a structure which resembled female external geni- talia. Both the labia majora and minora were nearly normal in size, the former extending to the posterior commissure, while the latter formed the frenulum. The skin and dartos of the scrotum divided into two lamina on reaching the postero-inferior part of the labia majora. The superficial layer continued as the skin and fascia of the femoral region, the inner lamina thickened into the labia majora. The minora was two membranous folds within the majora and surrounding the penis or enlarged glans clitoris. At this stage of the dissection, if one would disregard the latter enlarged organ, the cadaver was nearer a female than a male subject. THE PENIS AND VAGINA The penis in all respects resembled a glans clitoris which had developed into an organ that closely figured externally as male genitalia with a cone-shaped dilated urethra (fig. 1). At the large or vaginal end of the urethra was an opening that extended back into the uterus through the prostatic-cervix of the uterus (fig. 2), which will be described later. The penis was small, measuring a little more than 13 inch in length and } inch in diameter. The glans had a prepuce fused with the erectile tissue of the corpus cavernosum, and was only a rudimentary fold at the end of the organ. The dorsal vein, arteries, and nerves were regular and similarly related as those found in a normal subject. Externally, the urethral orifice of the corpus ‘avernosum urethra (fig. 1), measured 3 inch in diameter. This opening gradually increased in diameter until it was a little more than an inch in diameter at the urogenital diaphragm. In so far as we could note, there was no spongiosum tissue present in the urethral part of the organ. Both the urethra and the vagina opened into this enlarged urethra. The true urethra HERMAPHRODITISM IN MAN 57 itself was only about ¢ inch in length. This duct passed through the upper part of the prostatic-cervix portion of the uterus, while the vagina was located in the lower two-thirds and ex- tended upward and backward into the uterus proper. Pos- teriorly, the corpus cavernosum penis divided into two short erura (fig. 1) 2 inch in length. THE UTERUS The body of the uterus was separated from the bladder by the vesico-uterine fold of peritoneum in the usual manner. How- ever, the uterus as a whole was somewhat lower down in the pelvic cavity than is ordinarily found in normal cases. This was due possibly to the development of the organs—the fusing of one genital system with the other. The greatest width of the uterus was 1.5 em., with a total length of 5.5 cm.; the body was 4 em., and the prostatico-cervix 1.5 em. A uterine body cavity was perfectly developed, and measured nearly 5 em. This cavity extended into the uterus with little demarcation between the two organs. The entire cervix was fused with the prostate; in fact, the prostate was a mere enlargement of the cervix of the inferior extremity of the uterus. The uterus held the same relation to the prostate that utriculus prostaticus holds in a normal male subject. Not only the lumen, but the uterine glands and mus- cular walls could be easily defined (fig. 3). The ductus deferens entered the prostatico-uterine canal of the cervix by piercing its posterior wall (fig 2). A broad ligament was well developed, resembling in every detail a normal female subject except the course of the ductus deferens, which will be described later, and it was a little thicker and wider, due to the fact the uterus was a little lower in the pelvis as has been previously described. THE DUCTUS DEFERENS The ductus (vas) deferens differed in no respect from a normal male subject until it passed through the annulus inguinalis ab- dominis in connection with a very rudimentary ligamentum teres uteri (fig. 2). It then coursed alongside, and posterolateral THE ANATOMICAL RECORD, VOL. 19, NO. 1 5S HUBERT SHEPPARD to the oviduct, at first encircling the ovaries. When it reached the level of the uterus, it made a quick S-shaped turn, and en- tered the superior part of the cervix of the prostatico-uterus. The histological structures of the duct are very well developed. The epithelium surrounding the lumen is slightly disintegrated, as is shown by the photograph The cireular and longitudinal muscle layers are clearly defined, and in a number of sections the tunica propria and the inner longitudinal layer are also easily recognized (fig. 4). THE OVARIES AND OVIDUCT The ovaries measured about 1 inch in length and 1% inch in breadth. They were attached to the mesovarium in the usual way. However, the ovaries were found to be in a poor state of preservation for histological purposes; nevertheless, some of the materials stained sufficently well to demonstrate the ovarian tissue. One of the larger follicles as well as a number of smaller are shown in figure 5. A little below the folicles is a light area where the corpus luteum has disintegrated from the rest of the tissue. Each oviduct took a normal course to the proximal opening into the uterus (fig. 2). The course of each duct was at first almost horizontal, lateral, and posterior from its attachment to the uterus until it reached an inferior lateral portion of the pelvic wall where it came into relation with the uterine extremity of the ovaries. Then it coursed at right angles, and passed almost vertically upward along the mesovarial border of the ovary to the mouth of the infundibulum and the fimbriated extremity of the duct. Microscopically, the sections of the oviduct very clearly differentiated the various tunics; the serosa, the longi- tudinal, and the circular muscle layers show with marked clear- ness (fig. 6). The epithelium as well as the inner part of the — mucosa has somewhat disintegrated from the lumen. It was possible in many of the sections to define the epithelial cell structures. A lumen extended throughout the full extent of the duct. ee HERMAPHRODITISM IN MAN 59 THE TESTES The testes did not differ from a normal testicle, except. in size. The right testis measured 13 inch in length, $ inch in breadth and 1 inch in diameter anteriorposteriorly. The left testis was nearly the same size as the right except for length. It measured a little more than 1+ inch. Each testis lay upon and slightly laterally to the large ridge or fold beneath the scrotum. ‘This arrangement gave the scrotum its extremely large appearance when viewed in its normal state. The funiculus spermaticus had all of its usual structures, even the pampiniform plexus was easily worked out. A small round ligament, before mentioned, was fused with the funiculus as far as the point where the labia majora began. At this point it was lost and could not be traced any farther along the cord. This tissue, like the ovaries, was in a poor state of preserva- tion for histological study. However, in many of the sections the convoluted tubules could be easily differentiated (fig. 7). Only the shape of the tubule with its contents could be clearly defined. It was impossible to differentiate between sexual and sustentacular cells except in a few sections. In these better sections, a few interstitial cells could be observed under oil im- mersion. DISCUSSION According to Virchow, this individual subject would be an individuum uterusque generis, since both male and female organs are found almost equally developed. Klebs regards a herma- phroditismus verus as a subject who possesses both male and female genital organs united in it. In the specimen under con- sideration, we find two setis of reproductive glands. They were not united in the sense of ovitestes, but since both the ductus (vas) deferens and the oviduct (Fallopian tube) enter the uterus and, further, the round ligament and the spermatic funiculus have a union as well as a natural position and course, we can say that there was an indirect union. Even according to Kleb’s definition this would be an hermaphroditismus verus. 60 HUBERT SHEPPARD Gudernatsch says that ‘‘hermaphroditism in the sense that separate testicles and ovaries are formed has not been demon- strated beyond doubt.”” Except for minor variations which we have previously described, we find not only separate testicles and ovaries which are in their normal position in the body, but also a complete male and female urogenital system with the excep- tion of the urethro-vagina and the prostatico-cervix of the uterus. Here we have noted the fusion of the two systems into a single system where male and female are combined. Such a finding as this substantiates the old theory of Waldeyer that there is a bisexual anlage of the genital ridge. We cannot quite see how Benda’s theory, ‘that the primary anlage of the entire sexual system of the vertebrates must be regarded as female,’’ would harmonize with facts now recorded. A separate development would seem to be further substantiated by the fact that in every case of hermaphroditism on record there is always a sharp distinction between the two kinds of tissue, and never an undifferentiated mixture of both elements, as would be the ease if the germinal epithelium could produce either male or female reproductive tissue. In every male subject the prostatic utriculus, a homologue of the vagina of the female, can be demonstrated. It would appear from what we know of the embryological development of the urogenital system that there would be a fusion of the prostate, vagina, and uterus in an hermaphroditismus verus. This would no doubt explain the variation or fusions of the two systems found in the cadaver we are considering. HERMAPHRODITISM IN MAN 61 LITERATURE CITED Benpa, C. 1895 Hermaphroditismus und Missbildungen mit Verwischung des Geschlechtscharakters. Ergebn. d. allg. Path., Bd. 2, S. 627. Corsy, H. 1905 Removal of a tumor from a hermaphrodite. Brit. Med. J., vol. 2. GupernatscH, J. T. 1911 Hermaphroditismus verus in man. Am. Jour. Anat., vol. 11, pp. 267-78. Haxpan, J. 1903 Die Entstehung der Geschlechtscharaktere. Arch. f.Gynaek., Bd. 70, 8. 205. Hirrscurerp, M. 1905 Ein seltener Fall von Hermaphroditismus. Monatsschr. f. Harnkr. und sex. Hyg., Bd. 2, 8. 202. Janosix, J. 1887 Bemerkungen iiber die Entwicklung des Genitalsystems. Sitzungsber. Akad. Wiss. Wien, Bd. 99,3. Abt., S. 260. Luxsu, F. 1900 Uber einen neuen Fall vom weit entwickeltem Hermaphro- ditismus spurius masculinus internus. Ztschr. f. Hellk., Abt. f. Path., Bd. 21, S. 215. Meixner, K. 1905 Zur Frage des Hermaphroditismus verus. Ztschr. f. Heilk., Abt. f. prakt. Anat., Bd. 26, S. 318. Neucepaugr, E. 1908 Hermaphroditismus beim Menschen. Leipzig. Puitiers, J. 1887 Four cases of spurious hermaphroditism in one family. Trans. Obst. Soe. London, vol. 28, p. 158. Reizenstern, A. 1905 Uber pseudohermaphroditismus masculinus. Miinchn. med. Woch., Bd. 52, 8. 1517. Sarin, E. 1899 Ein Fall von Hermaphroditismus verus unilateralis beim Menschen. Verh. Deutsch. Path. Ges., Bd. 2, 8. 241. Scueckete, G. 1906 Adenoma tubulare ovarie (testiculare). Hegar’s Beitr. z. Geburtsh. u. Gyniick., Bd. 11, S. 263. Stmon, W. Hermaphroditismus verus. Virchow’s Arch. f. path. An., Bd. 172, Sap: Tournevx, F. 1904 Hermaphroditisme de la glande genitale chex la taupe femelle adulte et localisation des cellules interstitielles dans le segment spermatique. Comp. rend. de l’assoc. des. anat., Toulouse, p. 49. Ungerer, E. 1905 Beitrige zur Lehre vom Hermaphroditismus. Berl. klin. Woch., Bd. 42, 8. 499. Waupryer, W. 1870 Wierstock und Hi. Leipzig. EXPLANATION OF PLATES All the figures are untouched photographs of the organs described in this paper. Figures 1 and 2 are macroscopic photographs of the external and internal genital systems. The remainder of the figures are microscopic photographs. PLATE 1 EXPLANATION OF FIGURES 1 A photograph to show the external genital organs. The short penis has been dissected out with its crura and laid upon the pubis. The dilated urethra has been split and pinned open to show the small! opening into the vagina as it turns backward to enter the uterus. 2 A photograph of the same section from a pelvic view. The vagina and uterus have been laid open and pinned backward to the broad ligament. The ductus deferens can be seen on the right side near the upper extremity as it enters — the cervix of the uterus. Near the lower extremity of the uterus can be seen both oviduets coming off from the angle of the uterus. The bladder could not be shown in the photograph. 3 A microscopic section to show the lumen and muscular wall of a portion of the uterus. This was taken from the right side 2 cm. from the cornu. PLATE 1 HERMAPHRODITISM IN MAN HUBERT SHEPPARD 63 PLATE 2 EXPLANATION OF FIGURES r oy 4 A section of the ductus deferens to show the tunics. Considerable dis- integration has taken place in the lumen. However, all the layers of the duct show clearly in the photograph. 5 A section of the ovary. A large follicle is seen near the top of the photo-— graph. Two smaller follicles to the right can also be seen. Below and near the bottom of the photograph is a light area. This was an area of disintegrated corpus luteum. ort 6 A section of the oviduct taken about half-way between the ovary and the — uterus. 7 A low-power section of the testicle, to show the convoluted tubules the connective tissue among the tubules. HERMAPHRODITISM IN MAN PLATE 2 HUBERT SHEPPARD BOOK REVIEW Le Emopatir. By Prof. Dott. Adolfo Ferrata della R. Universita di Napoli. Vol. 1. Parte Generale, XVI and 1-482 pp., 21 colored lithographed plates and 8 text-figures. Milano: Societi Editrice Libraria, 1918. Price, unbound, L.30.00. This is one of the most interesting, complete, and usable books on morphological hematology ever published. It is the kind of book which unfortunately cannot be produced in this country, for no Amer- ican publisher could furnish the splendid colored lithographed plates and probably no publisher in this country would publish such an extensive text on a subject which necessarily appeals to a small audi- ence. The plates are of exceptionally high quality, and the figures are so arranged that the plates will prove very useful even for those who have difficulty with the Italian text. The text matter is arranged very systematically, and each chapter is followed by a very extensive bibliography. Citations to literature and discussions of theories are so numerous that the book will be of great value as a reference work to anyone working in this field. It should be accessible to every laboratory in which there is an interest in hematology. ' The book is far more than a compilation of the work of others. for there is a hardly a phase of the subject to which the author has not contributed by his own researches, the results of which have appeared in numerous previous publications. The work is really an extended résumé of Ferrata’s own work and that of his students and collabora- tors, Di Guglielmo and Negreiros-Rinaldi. Of special value is the fact that it has been possible to include the results of most recent research in this field. It is thus the only place where one will find a summary of much of this work. The chapter on technique, to which the first eighty-four pages are devoted, gives a very complete account of the modern methods of counting, haemoglobin estimation, fixation and staining of blood smears and of the blood-forming organs, with considerable space devoted to the methods of supravital staining of fresh blood and the making of permanent preparations of blood smears stained in this manner. Part II, sixty-three pages and eleven plates, deals with the red blood-cells. The results of supravital staining, the maturation of the red corpuscle, and the pathological morphology of erythrocytes, includ- ing polychromatophilia, basophilic punctation, Howell-Jolly bodies, ete., are prominent features of this section. Sixteen pages are devoted 67 68 LE EMOPATIE to the discussion of basophilic punctation. In regard to the origin of the basophilic granules it is to be noted that Ferrata has given up his former view that they are derived from the parachromatin of the nucleus. With Pappenheim and Askanazy he now agrees that they are of cytoplasmic origin. His general conclusion in regard to baso- philic granulation is that it represents a phase of maturation of normal erythrocytes in certain periods of embryonic life; it is atypical for the adult, and morphologically it corresponds to the basophilic substance of the primitive lymphoid erythroblast. In the normal adult the erythrocyte passes through a polychromatophilic phase in order to reach its final acidophilic state, but in pathologie conditions of the adult ‘conglobation’ of the basophilic substance during the polychroma- tophilic stage gives origin to the basophilic granules. Clinically, baso- philie granules appearing in more or less severe types of anemia indicate a return of the mechanism of maturation of the erythrocyte to an embryonic type. In this connection it must be remembered that Ferrata’s previous researches have shown that a condition analogous to basophilic punctation is a normal phase during the maturation of the erythrocytes of early mammalian embryos. Several plates are devoted to illustration of the maturation of the erythrocyte and megaloeyte. The numerous exceptionally clear figures include all important stages in the differentiation of red cells from the ‘hemocytoblast’ (primitive progenitor of all the granular leucocytes and erythrocytes) to the fully matured non-nucleated orthochromatie erythrocyte. Ferrata and Negreiros-Rinaldi have been successful in recognizing the very earliest stages in the differentia- tion of the red-cell series in a cell-type which they have named ‘pro- erythroblast.’ This cell retains the nucleoli of the ‘hemocytoblast’ Clymphoidocyte’ of Pappenheim), but shows some slight differences in other respects. The chromatin network is somewhat coarser and the light spaces between the chromatin strands are more sharply defined. The cytoplasm is more homogeneous and more basophilic and does not show the spongy differentiation of the primitive stem-cell. This cell is inserted between the lymphoid hemoblast of Pappenheim and the stem-cell. For the megaloblast a similar stage is recognized—the promegaloblast. Part III, pages 167 to 242, plates XI to XVI, deals with the leuco- cytes. In the evolution of the neutrophil leucocyte Ferrata distin- guishes between the ‘proneutrophilic myeloblast’ and the ‘neutrophilic promyelocyte.’ Excepting for the presence of fine azurophilic granules in a basophilic cytoplasm, the former resembles the hemocytoblast in structure. In the neutrophilic promyelocyte the fine azurophilic granules are gradually replaced by neutrophil granules lying in an oxyphilic cytoplasm and the nucleus gradually assumes the coarser structure which is characteristic of the myeloeyte. The proeosinophilic myeloblast contains very coarse azurophil granules and the eosinophilic promyelocyte eosinophil granules in addition. It should be pointed out here that most authors do not agree with Ferrata’s assumption of ~~ Ta.) = BOOK REVIEW 69 relationship between the character of the azurophil granulation and the further differentiation of the myeloblast, although it is generally con- ceded that the azurophil granulation of ‘myeloid’ cells differs from that of lymphocytes. Part IV, forty-four pages and one plate, deals with the blood-plate- lets. Naturally a large portion of this chapter is devoted to the various theories on the origin of blood-platelets and to discussion of the exten- sive literature on the subject. The discussion is unusually complete for a book of this kind. Ferrata derives blood-platelets from megakaryocytes, as originally discovered by Wright, and also from ‘monocytoid’ cells having azuro- phil granules arranged in small groups as in blood-platelets. These latter cells are found especially in the bone-marrow of the embryo. Part V, pages 313 to 399, dealing with the hematopoietic tissues, is the most interesting and original section of the book. Due con- sideration of the connective tissue as a diffuse hematopoietic tissue is a decided and much-needed innovation. The ‘hemohistioblast’ (resting wandering cell of Maximow, clasmatocyte of Ranvier) of the connec- tive tissue and the ‘hemocytoblast’ comprise a uniform anatomical system, identical in embryological origin and differential potentialities; they form the hematopoietic parenchyme in the widest sense of the word. The specific hematopoietic tissues of the bone-marrow, lymph nodes, and spleen are discussed first, this portion of the chapter being alto- gether too brief in proportion to the space devoted to the diffuse hema- topoietic tissue. The hemocytoblast, similar in structure to Pappen- heim’s lymphoidocyte, is the progenitor of all the bone-marrow cells, and a similar cell in ‘lymphoblastic function’ gives rise to the lympho- eytes of lymph nodes and spleen. The monophyletic theory is, there- fore, accepted by Ferrata, but not the extreme unitarianism of Weiden- reich and Maximow, for Ferrata believes in functional dualism to the extent that fully differentiated lymphocytes are incapable of differen- tiating into granulocytes or erythrocytes. In the spleen pulp the myeloid function of the hemocytoblast is retained to a certain extent, which explains the limited production of myeloid cells in the pulp of the normal adult. The section devoted to the ‘hemohistioblastic,’ or ‘diffuse hemato- poietic’ (connective) tissue is of special interest. The colloidal dyes (Trypanblau, Pyrrholblau, Lithiumearmine) are made use of for the purpose of determining the relationships of the cells of this tissue. The primitive cell of this tissue is the resting wandering cell (Maximow) derived from an amoeboid embryonic mesenchyme cell and giving rise to all the other types of cells of the connective tissue. These are divided into chromophobe (without dye granules) and chromophile (with dye granules) types. The latter include the resting wandering cells, fat cells, endothelial cells, and fibroblasts. The fibroblasts, on account of the character of their dye granules, are regarded as highly differentiated cells, while fat cells and endothelial cells are considered to be functional adaptations of the hemohistioblast (resting wandering cell). The chromophobe cells include plasma cells, mast cells, eosino- 70 LE PMOPATIE phils, and lymphocytes, and they are also differentiated from the hemo- histioblast which loses its capacity for storing colloidal dyes during their differentiation. In the opinion of the reviewer, much remains to be proved before this classification of Ferrata’s can be adopted. The whole structure is built up on the assumption that the reaction of the cells to the colloidal dyes is specific. Recent work of the reviewer! seems to indicate that the reaction is not specific, but that the behavior of cells toward col- loidal dyes depends entirely on functional and environmental condi- tions. In other words, the presence or absence of dye granules is not sufficient to enable us to distinguish between hemohistioblasts and lymphocytes, or between monocytes of the tissues and large mono- nuclears of the blood. Serious objection may also be offered to the view that the ‘hemo- histioblast’ is always a more primitive cell than the lymphocyte, and that the lymphocyte ( of normal circulating blood) is a differentiated mature cell incapable of being transformed to a granulocyte and inca- pable of reverting to a hemohistioblastic resting wandering cell. In this connection it is sufficient to refer to the recent work of Weill,? who has shown conclusively that lymphocytes, even those having the struc- ture of small lymphoevtes, are capable of differentiation into granulo- cytes. It is true that these observations were made on human and mammalian thymus, spleen, and mucosa of digestive tract, but until real or even functional differences between lymphocytes of the blood and those of the tissues have been demonstrated, they must be regarded as valid objections to Ferrata’s theory. Numerous objections to Ferrata’s view of the relationship between resting wandering cells and lymphocytes could be offered, but this is not the place for the lengthy discussion which would be necessary. Many of these topics are considered again in the following section, where the literature is given due consideration. ; Part VI, pages 400 to 460, deals with the morphogenesis of the cells of the blood. ‘The first part of the section is concerned with the genesis of the blood-cells of the embryo. Various theories are considered, but emphasis is placed on the results of the author’s own researehes. Al- though space will not permit discussion of this chapter, the reviewer wishes to call special attention to Ferrata’s own conclusions in regard to the relationship of the blood-cells. The first basophilic lymphoid blood-cells derived from the mesenchyme of the early embryo are not lymphocytes, but a special type of ‘primitive transitory hemocyto- 1 Downey, Hat 1917 Reactions of blood- and tissue-cells to acid colloidal dyes under experimental conditions. Anat. Rec., vol. 12. 1918 Further studies on the reactions of blood- and tissue-cells to acid colloidal dyes. Anat. Rec., vol. 15. ; 2 Wertn, P. 1919 Ueber die Bildung von granulierten Leukozyten im Karzinom- gewebe. Virchows Archiv, Bd. 220, Heft 2. 1919 Ueber die leucocytiiren Elemente der Darmschleimhaut der Siugetiere. Arch. f. mikr. Anat., Bd. 93, He‘t 1. 1919 Ueber das regelmiissige Vorkommen von Myelocyten in der Milz des erwach- senen Menschen. Arch. f. mikr. Anat., Bd. 93, Heft 1. BOOK REVIEW 71 blasts’ which are all under erythroplastic function. For a time they all differentiate into promegaloblasts, megaloblasts, and megalocytes, the primitive red-cell generation of the early embryo. In the second phase, that of the hematopoietic activity of the liver, the mesenchyme cell (hemohistioblast) differentiates into a new type of primitive cell, the definitive hemocytoblast in myeloid function which in turn differ- entiates into erythrocytes, granulocytes, and megakaryocytes. This second hemocytoblast corresponds morphologically to the ‘myeloblast’ or stem-cell of the adult. In the third (fetal) phase, during which the lymphoid tissue appears, the mesenchymatous hemohistioblast gives rise to a hemocytoblast of lymphoid function which produces lympho- cytes, although it is morphologically identical with the myeloid hemo- cytoblast. The different end-products are due to temporary functional differences only. According to this scheme all the blood-cells are traced back to the fixed tissue cell, the hemohistioblast, the cell which stores colloidal dyes in the connective tissue of the adult. In the early embryo this cell differentiates into the primitive transitory hemocytoblast, and this in turn to the primitive red cells of the embryo (megalocytes), while in the adult, lymphoid and myeloid hemocytoblasts (functional differ- ences only!) and monocytes are the products of its differentiation. The monocytes may also be derived from both the lymphoid and myeloid hemocytoblasts. This scheme seems to harmonize the actual observed facts with both the unitarian and dualistic theories better than any other scheme which has been presented. A good part of this section of the book is devoted to discussion of the unitarian and dualistic theories and the last fifteen pages to the doctrine of Ferrata. In part VII, pages 469 to 482, the author discusses the morpho- logical significance of the cells of the blood and the hematological formula. The discussion of the significance of azurophil granulation is of special interest. Ferrata takes the stand that the presence of azurophil granulation in a myeloblastic lymphoid cell indicates begin- ning differentiation toward a granulocyte, which may be either an eosinophil or neutrophil granulocyte, according to the character of the azure granules. The azure granules are not transformed into the specific granules of the leucocytes, but are replaced by the latter. The presence of azurophil granulation in myeloid cells, therefore, indicates maturity and beginning differentiation and is of greater significance than the mere temporary secretory activity assumed by Pappenheim. The reviewer has picked out only a few of the interesting and signifi- cant parts of the book for special mention. In closing he wishes to state that the book constitutes one of the most important recent addi- tions to hematological literature. The statement on the title page that it is a “‘Trattato per medici e studenti”’ is somewhat misleading, for it is more than an ordinary text-book. Hat Downey, University of Minnesota. ~% a? il ” ll - a Vi ‘3 ’ i 4 4 © | ~~» fr” a “hs ‘ J we rerip oor s “- ve Ratt ys , initials, al ' mi ob Ms ihn Gaiety” aad Lone Orinnl matte ; ots THs Ces igi? mrt be OT fo tu eee (5 ee . av x shia amet woloty ole ; tie ee 's i, .aeaiag ia walls. ' lg pr seats Ter iF) uanen cand Dis «' vu are a pega et meal on oF ) pero) wong wh, me rm matt “hd phere WE sidan ORV oho shen ty tukueobe im eae eit bale fer wait aoe Bint ab i NAN Mita!) J nurerchpoxtutl gL 0Rs 7 it » kabegipetct te cere | A ae Upiitr pret ‘ ait Waal» COMI) ata a ioe ' ery an De ae y . ab mir) Mi oerermapiy) <1 ese, ; Bs rishiiiy wueehn CM wir@iriosab wrt = t ‘4 Lied weal ' Jiud bandh tine thy a ay m1 * te ’ Sr ak < Par brates, approach each other in the center, and the first hint of their eventual fusion to create the posterior half of the future postcava is offered by a simple interanastomosis (fig. 3,*) at the level of the eighth spinal ganglia. Coincident with the merging of the subcardinals (figs. 4 and 5) occurs the formation of the proximal half of the postcava; this is already potentially present in the right vitelline vein, which, at first equal in size to the left (fig. 1, v. om. mes), grows larger (figs. 2 to 5, v. hep. rev.), and, DEVELOPMENT, SYSTEMIC VENOUS PLAN, ANURA 89 traversing the liver, establishes continuity with an apparently independent segment which is developed between the liver and the right posteardinal (fig. 2). This segment soon becomes confluent with the latter vein at the level of the fourth spinal ganglia (fig. 3), and the postcaval trunk is complete. Obviously, | v.vert ant. much of the blood in its return from the caudal regions of the body to the heart is now deflected through the postcava, and in time, as an increasingly greater volume of blood follows this more direct route, the portion of the original postcardinal veins between the postecava and the pronephric sinus of both sides gradually falls into disuse and atrophies, the right disappearing earlier than the left (figs. 5 to 7). 90 OTTO F. KAMPMETER y Changes as far-reaching as the above take place caudally. The most distal segment of the subcardinal (medial postcardinal division) does not fuse with its fellow, but undergoes reduction v Jug. In! —— AY N Vhep.ren 77 } cor lym.antsin 4\ AaB lot v.card post CR OMOM OMOMOROI® 3 Figure 6 and finally breaks away (figs. 4 to 6), thus severing the connec- tion between caudal vein and posteava. Hence, all of the blood from the hinder regions is compelled to flow through the expand- DEVELOPMENT, SYSTEMIC VENOUS PLAN, ANURA 91 ing lateral postcardinal divisions which may now be called the venae renales advehentes (Jacobsen’s veins, figs. 7 and 8), thence through the sinusoids of the mesonephroi to enter the postcava vjug.int—® + V. JUS ext. 7 —Vjuc. int Si.proneph. $ O#O Q fo} 3 = = s rr g =| V.Cav. post. ty, A “sy 4 of v.dors, lumb. MO ©6666 cor lym. _| post. dex: vV.ischiad, Figure 7 92 OTTO F. KAMPMEIER through the revehent branches. In the meantime, the paired abdominal vein has merged anteriorly into a single vessel which joins the hepatic portal vein (not shown in the diagrams) and so produces a second pathway of return for the blood-stream from the posterior region. Gradually, the two unfused and divergent rami of the abdominal vein remain united with the external iliac veins which extend out into the developing limb buds as the rudiments of the femoral veins. Extensions of the post- cardinals backward along the caudal vein (fig. 6) represent the anlagen of the ischiadic veins (v, ischiad.) which enlarge as the hind extremities develop and the caudal vein degenerates. The transverse iliac veins (v. iliac trans.), obliquely connecting the external iliac and ischiadic veins, are a later acquisition (fig. 8). As the mesonephroi are progressively differentiated and as they assume the function of urea excretion, the pronephroi suffer regression in a corresponding degree (figs. 7 and 8). During the growth of the tadpole a marked shifting of relations occurs, for, as the diagrams indicate, the pronephroi in earlier stages lie slightly back of the niveau of the sinus venosus and are directly placed in the path of the postcardinals, but later, owing to the atrophy of the proximal segment of these channels, they come to lie anteriorly, at the junction of the external and internal jugulars.’ In fact, the pronephric sinus at the time of metamor- phosis forms the terminus of the internal jugular where it ap- pears as a swelling (fig. 8), but the difference in diameter is gradually equalized by further reduction of the sinus. Changes like these are instrumental in bringing about the striking dis- similarities between the venous relations of the lymph hearts in embryonic and in adult stages. Further changes in this region that produce the definitive relations of the anterior lymph hearts to the veins are indicated in the following paragraph. Associated with the alterations of the large venous trunks, radical modifications take place in the series of intersegmental veins. Another paper will show how the first three of these are intimately concerned in the development of certain lymph- ‘In using the term ‘external jugular vein,’ I am following Gruby and Ecker; Goette and many other authors refer to this vein as the ‘inferior jugular.’ DEVELOPMENT, SYSTEMIC VENOUS PLAN, ANURA 93 atic channels, the third contributing largely to the formation of the anterior eae heart (fig. 2, cor lym. ant.). Only the mouth of the anterior vertebral vein (v. vert. ant.) of later stages, in vjug.int. P vjue. int. v.vertant: v.vert.ant. Ole cor lym.ant. sin. © v.Subclav. mesonephros, Vv. dors.lumb. ! sO Oo @ 6 / XN f ! 4 < Fe a < re ! v. iliac v.abdom. a! viliac. v.vert. post. y, x \. vert. post. ere cor lym. con NE. cor lym. r v.ischiad—§ SS POST In. ~ v.fem. V.fem. —Vv.cut. fem.post- Figure 8 OF OTTO F. KAMPMEIER other words, the efferent channel of the anterior lymph heart, can be considered as a direct transformation or derivative of the proximal portion of the third intersegmental vein, the re- mainder being an outgrowth from the latter just medial to the lymph-heart anlage. During the period of the degeneration of the anterior segments of the postcardinals and the consequent dwindling of the pronephric sinuses, each anterior vertebral vein, besides extending at first in a posterior direction, soon develops a second fork which extends forward and eventually establishes a connection with the internal jugular some distance anterior to the pronephric sinus. Sometime later, the original connection of the anterior vertebral vein with the vestige of the pronephric sinus, now the terminal portion of the internal jug- ular, breaks away, and the secondary junction farther cephalad becomes the permanent outlet of the lymph stream from the anterior lymph hearts. These changes are clearly expresedin the diagrams 5 to 8, inclusive. During development all of the intersegmental veins back of the anterior lymph hearts become interjoined by a longitudinal anastomosis (figs. 2 and 3) which may be termed the lateral vein (v. lat.) because it courses in the lateral-line region and is without doubt homologous with a similar vein in the tailed amphibians. Subsequently, the termini of all intersegmentals except the 9th and 11th (fig. 7) in toad embryos become very much reduced or vanish, although variations happen, such as the persistence of the vessels in intervals other than those. The anterior one of the retained intersegmentals becomes the trans- verse piece or mouth of the dorsolumbar vein (figs. 7 and 8, »v. dors. lumb.), while the greater extent of the lateral vein becomes its longitudinal portion (rami iliolumbalis and iliacus). While these changes are taking place, the posterior lymph heart (cor. lym. post.) on each side® develops from a lymphatic plexus along * Bufo possesses only one posterior lymph heart on each side. Among the frogs there are multiple posterior lymph hearts, from two to four in number on each side in the adults; thus in the American common, species, Rana pipiens, there are normally two pairs of these (diagram 9) with the occasional vestige of a third, present in the tadpole. The development of thesé hearts and their relation to the veins will be considered in one of the subsequent papers. DEVELOPMENT, SYSTEMIC VENOUS PLAN, ANURA 95 sin. ven. v.cav.ant. v. jug: int. v, jug. ext. v.vert. ant. cor lym. v. subclav: aye Vv. brach. | S V. Cav. post. v. dors. Lumb. vy. ren.adv. v. abdom. viliac. vteni: v. vert. post. é IC) v.iliac. * Sor f ; trans. v.ischiad. v.cut. fem. post. Figure 9 96 OTTO F. KAMPMEIER the lateral vein at the level of its 11th intersegmental branch (fig. 5). The proximal portion or junction of the latter branch with the posteardinal (vena renalis advehens) becomes the mouth or terminal segment of the posterior vertebral vein (v. vert. post.) and the caudal part of the lateral vein becomes its distal extension (figs. 7 and 8). A break occurring in the lateral vein between the two parts of it, referred to the longitudinal portion of the dorsolumbar and the posterior vertebral veins, respectively, establishes the independence of these two veins. In the meantime the posterior lymph hearts have formed a connection with the corresponding posterior vertebral veins, so that these channels now become the outlet of the lymphatic drainage of the posterior region of the body. The shifting of the mouth of the posterior vertebral vein back along the ischiadic vein up to the point where the transverse iliac vein is forming is clearly indicated in figures 7 and 8. These diagrams show how easily the variations that are so common arise by the expansion, reduction, or persistence of different segments of the originally symmetrical intersegmental veins, resulting in different relations with the main venous trunks. The degree of displacement, during development, of the various components of the venous conduit system, brought about by the more rapid elongation of some and the suppression of others, may be readily determined by comparing the successive stages with reference to the relatively fixed positions of the spinal gan- glia, as indicated in the diagrams. ee nal : Pe 1 ig Bae tivnainnes y ~ ¥ bl Ree METH AbD vir vial Porvoo Wii levwt VAC WALaiion ‘ } iy aE ST “ie fae nutes pal) etary rt i otis: hea dare ba rl hije tie v4 privy ' por aoyyowtien ta lived andar ate vevanhdare ? ib ptbclatl ¥A es wohiioy 4 tpi of Phe le iy qe Resumen por el autor, H. E. Jordan, Universidad de Virginia. Estudios sobre la estructura del mtisculo estriado. VII. El desarrollo del sarcostilo del mtisculo alar de la avispa, con consideraciones sobre la base fisicoqufmica de la contraccién. La estructura del sarcémero del relativamente grosero sarcos- tilo del miisculo alar de la avispa susministra la base de un intento de explicacién fisicoquimica consistente sobre la contraccién muscular. Las metafibrillas extremadamente pequefias que con- stituyen este sarcostilo, homélogo de la miofibrilla, del mtisculo estriado de los vertebrados, exhiben durante la contracci6n exact- amente los mismos cambios estructurales que la fibra muscular estriada voluntaria en conjunto. El cambio esencial durante la contraccion se refiere a la divisién igual de la substancia fuerte- mente tingible del disco Q al nivel del mesofragma y el movi- miento de las mitades resultantes en direcciones opuestas, apli- cindose contra los telofragmas terminales del sarcémero, donde se forman las bandas de contraccién. La causa de la contrac- cién muscular esté localizada en este movimiento de cristaloides entre las particulas coloidales (submicras) de los segmenos claros terminales. El acortamiento y aumento de espesor de los sarc6- meros durante la contraccién se interpreta como el resultado de un cambio en la forma de las partfculas coloidales intrafibrilares que pasan de la forma elipsoidal a la esférica, a causa de un au- mento en su tensién superficial resultante de la disminucién de sus cargas eléctricas superficiales, la cual sigue al paso de elec- trolitos entre ellas durante el movimiento de la substancia fuerte- mente tingible desde el mesofragma a los telofragmas. Translation by José F. Nonidez Cornell University Medical College, N. Y AUTHOR'S ABSTRACT OF THIS PAPER ISSUED BY THE BIBLIOGRAPHIC SERVICE, MAY 24 STUDIES ON STRIPED MUSCLE STRUCTURE Vil. THE DEVELOPMENT OF THE SARCOSTYLE OF THE WING MUSCLE OF THE WASP, WITH A CONSIDERATION OF THE PHYSICO- CHEMICAL BASIS OF CONTRACTION H. E. JORDAN Department of Histology and Embryology, University of Virginia THIRTEEN FIGURES (TWO PLATES) INTRODUCTION In the last number of this series of studies® it was shown that the constituent sarcostyles of the wing muscle of the wasp ex- hibit the same changes during contraction, with respect to the cross-striations, as do the complete fibers of striped muscle gen- erally, namely, a reversal of striations as regards a deeply stain- ing substance of the dim disc. It was assumed that the relatively coarse, cylindric sarcostyle of the wasp’s wing muscle is the homo- logue of the more delicate myofibrils of vertebrate striped muscle. If this assumption accords with the facts, then Schaefer’s® explanation of the appearance of a reversal of striations during contraction, as an optical illusion due to the accumulation of intersarcostylic fluid at the telophragma levels of relative con- striction, must be erroneous. Moreover, the idea that this sarcostyle during functional contraction swells at the levels of the dim discs, thus producing a relative constriction at the level of the telophragma, is itself erroneous. As was shown in the previous number,® the beaded condition of the sarcostyle is the result of an artificial contraction following the osmotic action of a hypotonic medium. The functionally contracted sarcostyle, while it shortens and thickens, maintains meanwhile, neverthe- less, a straight, unbeaded contour. None the less it seems de- sirable to establish definitely the actual morphologic status of the wasp’s wing-muscle sarcostyle by a study of its development. 97 98 H. E. JORDAN This is the primary purpose of this investigation, namely, to trace the developmental history of the wasp’s wing-muscle sar- costyle with a view to determining its value in terms of the elementary myofibril of vertebrate striped muscle. The evi- dence which will be given below seems conclusive that the sar- costyle of the wasp’s wing muscle and the myofibril of verte- brate striped muscle are actually strictly homologous elements. This being so, it follows that in our efforts to discover the ulti- mate physicochemical basis of contraction we may more profit- ably, and quite legitimately and confidently, confine ourselves to the relatively much coarser sarcostyles of certain insects’ wing muscle (e.g., Diptera, Hymenoptera, and Coleoptera). The second purpose of this investigation is finally to attempt a physicochemical interpretation of the structural changes suf- fered by the sarcostyle during contraction, and to formulate a consistent hypothesis in explanation of the cause of muscle con- traction. The entire series of these studies on muscle structure had for one of its chief objects the accumulation of sufficiently numerous and precise data for the establishment of a correct physicochemical interpretation of muscular contraction. MATERIAL AND METHODS The material available for this study consists of two fairly complete series of specimens ranging from the newly hatched larva to the older pupae, one series fixed in 95 per cent alcohol, the other in a 10 per cent solution of neutral formol. For this material I am indebted to Mr. Massie Page. For the purposes of the present problem we may confine ourselves to four salient developmental stages: 1) the oldest larval stage (or youngest pupal stage), namely, one in which the thorax is outlined and wing pads are discernible, but no external leg rudiments; 2) an intermediate white pupa; 3) alater gray, or slightly pigmented, pupa, and, 4) the black, almost mature, pupa. The thorax was embedded in paraffin. Sections were cut at 4u, and stained with iron-hematoxylin, followed in some cases by eosin counterstain. STRIPED MUSCLE STRUCTURE 99 DESCRIPTION In the youngest, legless pupal stages very delicate wings are already present. Serial sections through the thorax show the imaginal discs still in continuity with the ectoderm ventrocau- dally. Here, then, occur the initial myoblasts (fig. 1, a and d). Older stages in the muscle histogenesis occur anterodorsally (fig. 3 and 4). Between these terminal levels occur intermediate developmental stages (fig. 2, c). The initial myoblasts are long, fusiform elements with a vesic- ular, centrally located nucleus. The nucleus originally con- tains a single, dense, chromatic nucleolus. The latter subse- quently divides, the nucleus now containing a pair of nucleoli. This condition foreshadows the ensuing direct nuclear division. The myoblasts fuse terminally, their tapering ends overlapping (fig. 1, b), to form the definitive muscle fibers. Meanwhile the nuclei multiply greatly by amitotic division. No mitotic figures were seen in the myoblasts or later muscle fibers at any. stage. The muscle fiber accordingly arises by fusion of originally dis- crete cells, not solely and primarily by growth of the myoblasts. The nuclei multiply by direct division chiefly in planes perpen- dicular to the long axis of the myoblasts, thus forming axial columns of nuclei (fig. 1, b); but to some extent also by division in the longitudinal plane, thus originating more peripheral nuclei. Appearances like those illustrated in figure 2, c, repre- sent in part the latter sort of division, but in part also no doubt levels of sections where the tapering ends of fusing myoblasts overlapped. Already in the earliest myoblasts, like those of figure 1, a, an occasional peripheral myofibril is faintly discernible. The nature of this material does not permit of any definite statement regard- ing the origin of the myofibrils. I am unable to determine whether the original fibrils arise as such or by the alinement and subsequent coalescence of precursory myochondria. Nor can I be quite certain whether later fibrils arise by longitudinal divi- sion of preexisting myofibrils, or independently. I incline to think that the later myofibrils arise chiefly independently; at 100 H. E. JORDAN any rate, there is no clear evidence of a longitudinal splitting. The fibrils soon extend uninterruptedly through several origi- nal cell limits, and they remain for a relatively long time homogeneous. In figure 2 (a and 6) are illustrated trans- verse sections of myoblasts corresponding with a and 6 of figure 1. Illustration ¢ of figure 2 represents an older myoblast. Con- nective-tissue cells occur among the myoblasts. At least some of these divide by mitosis. Many of these cells become fat- cells. The cell c.t. of figure 2 is at an early stage of differentiation into a fat-cell. The earlier muscle fibers, formed by the fusion of myoblasts, grow rapidly in diameter (fig. 3). Both nuclei and myofibrils meanwhile undergo enormous numerical increase. In a trans- verse section (fig. 3) the nuclei, now granular and more chromatie, appear to be scattered at random. Longitudinal sections of fibers at this stage (fig. 4), however, show that the nuclei are arranged in long columns, in single or double file. The connec- tive tissue cells have also meanwhile increased greatly in num- ber. The interfiber spaces have a diameter approximately equal to that of the muscle fibers. These spaces are closely packed with stout, fusiform, and irregular connective-tissue cells. The latter subsequently differentiate largely into huge fat-cells. The myofibrils are still homogeneous and quite delicate. In trans- verse section they have the appearance of fine granules (fig. 3). Passing now from the stage of the oldest larva to that of the white pupa, with well-developed wings and legs, the wing-muscle fibers are seen to have enlarged enormously (fig. 5). The nuclei are numerous, but of smaller size in transverse section than in the preceding stage. Longitudinal sections of such fibers (fig. 6) reveal the fact that many of the nuclei are now greatly elongated elements. These continue to divide amitotically. The fiber is enveloped by a delicate sarcolemma. In certain cross-sections the peripheral myofibrils appear to be arranged in radial lines (fig. 5). This is the sole evidence that myofibrils may in part arise by longitudinal splitting of preexisting fibrils. The myofi- brils are now relatively coarse (figs. 5 and 6), but still clearly unstriped, and between the fibrils appears a very finely granular sarcoplasm (fig. 6). STRIPED MUSCLE STRUCTURE 101 Thus far there is no indication of even a telophragma. In a slightly older pupal stage (gray pupa), however, this membrane has made its appearance (fig. 10). The myofibrils, or sarcostyles, are now relatively very coarse, as may be seen by comparing figure 7 with figure 5 of the previous stage, and with figure 8 from the adult muscle. The stages of muscle development in the gray pupa are of the utmost significance in this connection. We meet here with the initial steps in the origin of the cross- striations due to the presence of dim discs. Certain large masses of fibers are composed of sarcostyles in which only the telo- phragmata have appeared (fig. 9, a). In other masses the sarco- styles contain also delicate, but deeply staining, Q-dises (fig. 9, b). Insuch sarcostyles the telophragma has changed to an only relatively faintly staining membrane. Still other large masses of fibers consist of sarcostyles with relatively wide Q-dises (fig. Gre); In certain other groups of fibers the Q-dises appear double (fig. 9, d), and occasional sarcostyles of such groups reveal very clearly constituent finer elements, the metafibrils (fig. 9, e). The clear indication of metafibrils, as in e of figure 9, may probably represent an artificial condition; but that the sarcostyles actually are composed of still finer fibrils seems demonstrated by the conditions which obtain where the muscle is attached to the hypoderm (fig. 10). Here the sarcostyles appear to break up into very fine ‘tendinous’ fibrils. The transition from muscle to tendon appears to be through direct continuity of muscular metafibrils and tendon fibrils The latter stain deeply in very dilute solutions of eosin, in contrast with the muscle which re- mains unstained. The metafibrillar composition of the sarco- styles is a point of cardinal significance with respect to the physicochemical explanation of contraction, and will be fully discussed below. The order of development of the cross-striations here disclosed is also a fact of much importance. The Q-dise appears only after the telophragma becomes discernible. The Q-discs are at first only very delicate, and only gradually attain their typical width between successive telophragmata. Coincident with the appearance of deeply staining Q-discs, the telophragmata suffer THE ANATOMICAL RECORD, VOL. 19, NO. 2 102 H. E. JORDAN a diminution of staining intensity. The meaning of the double condition of the Q-dises, as in figure 9, d, is uncertain. It may have the same significance as in the mature sarcostyles, namely, indicative of an early phase of contraction. The foregoing observations are specially significant by reason of the light they throw on the question of the function of the telophragmata. The data strongly suggest that the telophrag- mata furnish the pathways along which are transported the materials which contribute to the formation of the dim dises, as well as the materials which supply the nutritive demands of the sarcostyles. The genetic order of events here revealed explains the horizontal alinement of striations in cross-striped muscle. This matter also will be reverted to and more fully discussed below. Thus far no evidence appears, either in the formalin or alcohol- fixed preparations of sarcosomes. The latter appear first in formalin-fixed muscle of the almost mature black pupa (figs. 11 and 12). A largely lipoid nature of these sareosomes is suggested by the fact that they entirely disappear in muscle of this stage fixed in 95 per cent alcohol. The sarcostyles have attained almost their definitive diameter (compare figs. 12 and 8 and figs. 11 and 13). In longitudinal sections (fig. 11) the sar- cosomes appear spheroidal, but transverse section at this stage reveal the fact that they are already laterally somewhat com- pressed, and so possess short, blunt, lateral wings (fig. 12). Generally only two sarcosomes occur to an intertelophragma space, indicating that the telophragmata offer an effective bar- rier against their passage through these levels, and suggesting that the materials for their elaboration were also transported through the telophragmata, a sarcosome each being contributed by one telophragma. Comparison of figure 12 with figure 8, the latter from an adult muscle, shows that the sarcosomes undergo considerable subsequent growth, a circumstance in- volving still greater compression between adjacent sarcostyles, with the formation of longer, thinner wing processes. The ~ relatively late origin of the sarcosomes, that is, just prior to functional activity of the wings, suggests a close relation between a Oe ee ————- . STRIPED MUSCLE STRUCTURE 103 sarcosomes and the metabolic requirements of the relatively very rapidly contracting wing muscle. In figure 13 are illustrated three successive stages in the con- traction of the sarcostyle of the wing muscle fiber of an adult wasp. The sarcostyle a is in acondition of repose. The sar- costyle 6 is at an early phase of contraction. The Q-dise has become bisected by the appearance of an H-dise. The deeply staining substance of Q is accumulating at the levels nearest the telophragmata. The sarcostyle ¢ is at a still later phase, when the deeply staining substance of the sarcoplasm has aggre- gated about the telophragma, so that now this membrane bisects a dark disc, instead of bisecting a light dise as previously. A true reversal of striations, as regards this deeply staining con- stituent of the sarcoplasm, has been effected. Sarcostyle d is in almost complete contraction. The sarcostyle has become thicker, and the sarcomeres relatively shortened. The deeply staining substance about Z in sarcostyle c has here condensed so as to form a contraction band of the contracted fiber. The double nature of this band is clearly shown in sarcostyle d. The telophragmata are, however, no longer discernible. The optical disappearance of the membrane Z in sarcostyle d is interpreted as resulting from the thickening of the sarcostyle, effecting thus a drawing out radially and a consequent thinning of this mem- brane to a point where it is no longer within the range of micro- scopic vision. The above seriation of stages in contraction of the adult sarcostyle gives the key for the interpretation of figures 11 and 9, d, of immature sarcostyles. Sarcostyle d of figure 9 would thus appear to be in an early stage of contraction, the sarcostyle of figure 11 at a later stage corresponding with that of ¢ of figure 13. Apparently the immature sarcostyles are capable of some degree of functional contraction even before the wings are moved in flight. 104 H. E. JORDAN DISCUSSION The foregoing description shows that the wing-muscle fiber of the wasp is essentially homologous with voluntary striped- muscle fibers generally. The fiber is a multinucleated structure resulting from the fusion of originally discrete myoblasts, and sub- sequent growth, accompanied by an increase in the number of myofibrils and by the amitotic multiplication of the nuclei. The fibrils first appear as homogeneous elements, which only later become cross-striped. The wing muscle of the wasp, as that of Hymenoptera, Diptera, and Coleoptera generally, differs, however, from the usual type of voluntary striped muscle, in the definitive stages of its differentiation, in that its fibrils grow to relatively enormous radial dimensions. But the develop- mental history of this relatively very coarse sarcostyle demon- strates its strict homology with the more delicate myofibrils of vertebrate skeletal muscle. The question then arises concerning the functional significance of the relatively coarse sarcostyle of certain insects’ wing muscle. Clearly the coarse, cylindric condition of the sarcostyle bears no direct causal relation to flight as such even among insects, since in the Orthoptera and certain Odanata the wing muscle fibers of the thorax are characterized by lamellar ‘sarcostyles’ with constituent very delicate myofibrils. When we seek for a possible explanation of the difference in girth of sarcostyles in the several groups of insects, we note the fact that what distinguishes the flight of Diptera, Hymenoptera, and Coleoptera from that of the Orthoptera, for example, is not so much the rapidity of flight as the ability on the part of the former groups to sustain rapid flight for relatively long periods of time. The suggestion then presents itself that a relatively coarse type of sarcostyle, characteristic of wing muscle of which is demanded long-con- tinued function, may somehow better subserve the conditions of this demand than a structure characterized by relatively deli- cate cylindric or by lamellar sareostyles. Such hypothesis is supported also by the fact that the sarcostyles of the analogous pectoral muscles of the humming bird and the bat are y - - — oo —_- STRIPED MUSCLE STRUCTURE 105 relatively coarse cylindric structures. However, all specula- tions along these lines lose plausibility in view of the definite fact that also the coarse, apparently unitary, sarcostyles of wasp wing muscle resolve themselves finally into extremely minute constituent fibrils (metafibrils). This is true also of the lamellar type of wing muscle sarcostyle (e.g., mantis’). It might then perhaps be argued that the coarse, so-called sarcostyle of the wasp’s wing muscle is not actually the homologue of the myo- fibrils of, for example, human leg muscle, but in fact represents a fascicle of such fibril homologues. ‘The apparent force of such argument, however, is neutralized by the fact that also the myofibrils of mammalian skeletal muscle may be seen to con- sist of collections of still finer fibrils. The sarcostyle of the wasp’s wing muscle differs, moreover, from the lamellar, so-called sar- costyle of Orthoptera, in that the latter includes relatively fewer constituent fibrils and relatively much larger quantities of intra- sarcostylic non-fibrillar sarcoplasm. Successively more detailed analysis of muscular fibrils reveals successively finer constituent meta-fibrils up to the limits of visiblity. As above described, however, and already explained, the early stages in the devel- opment of the wasp’s wing-muscle sarcostyle show that it is strictly homologous with the myofibril of vertebrate striped muscle. Clearly, also, rapidity of function, or long-sustained function, is not directly related to complexity of cross-striation; for the wasp’s wing muscle, and vertebrate cardiac muscle, is characterized by a relative simplicity of striation. Complexity of striation, resulting from the presence of an additional N-disc, as in insect leg muscle generally, would thus appear to be related to force of function rather than to rapidity or long continuance of function. Insect wing muscle generally, however, differs from voluntary striped muscle of vertebrates in the occurrence of numerous, relatively large sarcoplasmic granules or sarcosomes in the former. But comparable elements occur also in the analogous pectoral muscles of bats and birds (Thulin'*), and in mammalian heart muscle (Bullard'!). The common factor in the conditions under- lying the peculiar function of these three types of muscle is the 106 H. E. JORDAN ability of long-sustained function. The evidence suggests that large and abundant sarcosomes subserve the peculiar metabolic needs of muscles which act continuously for long periods of time. The absence generally of at least large and abundant sarcosomes in insect leg muscle, and in vertebrate skeletal muscle generally, suggests that forceful function only at intervals does not necessi- tate exactly the same type, or at least the same degree, of support of its metabolic requirements. The sarcosomes develop relatively late. They appear first in the almost mature (black) pupa (fig. 11). They are at first spherical in shape; subsequently they become modified into winged elements, the result of mutual pressure between the ad- jacent growing sarcostyles and the enlarging sarcosomes. As was suggested in a previous article,’ the winged type of sar- cosome probably largely persists throughout the life of the indi- vidual. Microchemical evidence was also given indicating that, besides a predominant lipoid constituent, the sarcosomes, at least in the later phases of elaboration, include an additional substance, possibly a carbohydrate. The very definite arrange- ment of the first formed, spherical sarcosomes, two to each sar- comeric interval, suggests that the material for their elaboration enters the intersarcostylic spaces via the telophragmata. A detail in muscle histogenesis about which there has been much confusion and unprofitable speculation concerns the fact of the regular horizontal alinement of identically differentiated levels of the cross-striped myofibrils of a striped muscle fiber. The question arises as to how these alternating discs of adjacent fibrils are first brought into horizontal alinement. If the cross- striped myofibrils arise originally independently of telophrag- mata, as the illustrations of Godlewski®* and of Luna" for example, purport to indicate, then it is almost inconceivable how they may subsequently be brought into horizontal alinement. Whatever idea different investigators may hold regarding the origin of the initial myofibrils in various instances, whether as fibrils, mitochondria, or as prefibrillar myochondria which sub- sequently coalesce to form fibrils, all agree that the first genuine myofibrils are originally apparently homogeneous and only sub- STRIPED MUSCLE STRUCTURE 107 sequently become cross-striped.' The illustrations of God- lewski, while showing cross-striped myofibrils unconnected by telophragmata in young myoblasts of mammals, give no indi- cation of how the secondary myofibrils originate. Possibly Godlewski failed, or was unable by reason of their extreme ten- uity, to see the telophragmata actually spanning the interfibrillar spaces among the original myofibrils. Be this as it may, we possess two definite observations which explain how this trans- verse alinement of identically differentiated levels of the myofi- brils of a muscle fiber is produced. The clearest evidence concerning this point accrues from the present investigation. It seems perfectly plain in this material that telophragmata precede the appearance of Q-discs (figs. 9 and 10). It was shown in previous papers®* that the telophrag- mata are intimately connected with the sarcostyles and with the peripheral sarcolemma. In this way each sarcostyle is brought into relation with the interfiber tissue spaces and thus with the nutritive tissue fluid. Assuming that the telophragmata are pathways for the entrance and exit of materials between the 1M. R. Lewis, however, claims that in the myocardium of the chick embryo it can be demonstrated by a certain fixing and staining technic that the ‘fibrils’ are completely cross-striated from their first appearance (Johns Hopkins Hos- pital Bulletin, vol. 30, p. 1). Moreover, she interprets the ‘fibrils’ as fixation products, a view long since urged for striped muscle geneally by Van Gehuchten (La Cellule, T. 4, p. 247, 1888), but never widely accepted. The cross-striations she regards as genuine fundamental structural features of the myoblast as a whole. If the conclusion here reached with regard to the artificial nature of the fibrils of the primitive myocardium of the chick were applied to the wing muscles of the wasp, we would be obliged to interpret the sarcostyle (homologue of the vertebrate myofibril, as above demonstrated) of the latter muscle as a developed and differentiated fixation product; since, no one I suppose, would seriously attempt to explain this definitive sarcostyle of adult wing muscle of wasp as also an artifact. It may be suggested that the reason why the primitive myofibrils described by certain investigators in cardiac muscle are not discernible micro- scopically in living myoblasts is not because they are not actually present, but because they are relatively fluid and because in consequence the refractive index of their sarcoplasm is so close to that of the interfibrillar sarcoplasm that the contrast between the two is insufficient to permit of clear differentiation under the microscope. The coagulative effect of fixation may bring about a greater relative difference between the refractive indices of the two sarcoplasmic colloids, and so render visible the denser fundamental sarcoplasmie fibrils. 108 H. E. JORDAN sarcostyles and the interfiber tissue spaces (and this would appear to be their chief function), it becomes clear why the secondary modification of the originally homogeneous sarcostyles, namely, the formation of the Q-dises, follows the development of the telophragmata. Such genetic course explains at once the reason for the maintenance of a strict transverse alinement. The in- vestigations of Macallum™ and of Menten" have shown that the dim discs contain potassium salts, chlorides, and phosphates. The presence of these substances in these regions may be the reason for their deeper staining capacity. These substances, con- sidered physicochemically, are soluble erystalloids, at least in part electrolytes, and their segregation in the middle of the colloidal sarcomeres against the mesophragma, after entrance is thus explained. The difference in staining reaction of the telophragmata at the several successive early stages in the development, from the viewpoint of the relative amount of Q-substance, supports the idea here advocated, namely, that the materials for the produc- tion and growth of the Q-discs enter via the telophragmata. In figure 9, a, the telophragmata are relatively coarse and stain deeply. In b, where a thin Q-dise has appeared, the telophrag- mata are now delicate and relatively pale. The sarcostyle a may be interpreted as at the stage where the telophragmata are saturated with the deeply staining material, which in b has become segregated in the delicate Q-disc. To the latter is later added more of similar material to produce the relatively thick Q-dise of sarcostyle c. In view of the fact that the sarcostyles are closely connected with the telophragmata, the subsequently stratified sarcostyles (differentiating in the manner indicated through segregation of crystalloids entering the colloidal sar- comeres through the telophragmata) must of necessity hold their alternating strata in horizontal alinement. The other pertinent observation in this connection concerns the mode of the development of the myofibrils in the body muscle of the newly hatched rainbow trout.’ The same _histogenetic series of events in trout has been described also by Heidenhain.‘ Here the myoblasts originally contain a single, coarse, homo- —r ~~ STRIPED MUSCLE STRUCTURE 109: geneous, deeply staining, cylindric myofibril lying close to the nuclear wall within the cytoplasm. ‘The origin of this initial sarcostyle could not be determined. This primordial sarcostyle produces four secondary sarcostyles by two practically simul- taneous longitudinal divisions. These secondary sarcostyles as- sume a stout lamellar form, and subsequent sarcostyles arise only by successive radial and central longitudinal fissions. Thus while the sarcostyles, both peripheral lamellar and central cylin- dric, become cross-striped during the early stages of histogenesis, all subsequent myofibrils must maintain a similar alinement of their different alternating strata by reason of their origin by longitudinal division of already striped fibrils and their continued interconnection through the original telophragmata. Telo- phragmata are discernible following the first division of the initial sarcostyle. The available definite evidence therefore indicates that the cross-striations, as regards the Q-dises, only follows the appearance of telophragmata connecting with the peripheral sarcolemma, and so with the interfiber tissue spaces; and that the stratification results from the intake via the tel- ophragmata of soluble erystalloids which become segregated in the Q-dise. The foregoing descriptions and discussions, together with the data comprised in the previous papers of this series, lead naturally to an attempt to formulate a correct interpretation of the struc- tural changes which the sarecostyle undergoes during contrac- tion, in terms of physicochemical factors, and to an effort to explain muscle contraction in terms of these changes. The spe- cific central problem narrows itself down to a question of the in- timate structure and physical chemistry of the contracting single sarcomere of the relatively coarse sarcostyle of the wasp’s wing muscle. The sarcomere is bounded at both ends by a true membrane, the telophragma. Its middle is occupied by a dise of variable width, the so-called Q- or dim disc. This dise is composed of a substance which appears darker in unstained preparations, and which takes a deeper stain in fixed preparations treated with basic dyes. It contrasts in these respects with the lighter por- 110 H. E. JORDAN tions, halves of so-called J- or clear discs, intervening between it and the terminal telophragmata. The sarcomere is bounded peripherally by a layer which has the properties of a semipermeable membrane, as demonstrated by its response to hypo- and hyper tonic salt solutions. This layer, the sarcostylic membrane, is intimately connected with the telophragmata. Bisecting the Q- disc there occurs a delicate dividing structure, presumably a membrane, as demonstrated by the equal division of this dise in contraction along the midline, the mesophragma. This mem- brane, however, is not discernible as such in this sarcomere under the highest powers of the microscope. Minute analysis reveals the fact that the apparently homogeneous sarcomere consists in fact of ultimate metafibrils. The latter are intimately at- tached to the telophragmata. Macallum” and Menten" have shown that the Q-dise contains segregated chlorides, phosphates, and potassium salts. The presence of these substances in this area presumably accounts for the ‘dim’ appearance and the deeper staining capacity, possibly also for the relatively greater aniso- tropy, of this dise in contrast with the terminal J-segments. These salts represent soluble crystalloids, therefore, at least in part, electrolytes, and give to the Q-dise a composition physico- chemically different from the predominantly colloidal terminal clear portions. The sarcomere, therefore, consists of a cylinder of minute fibrils enveloped by a peripheral membrane, each col- loidal fibril containing medially a mass of segregated crystalloids. Through the terminal telophragmata of the sarcomere, each fibril (metafibril) is placed in capillary relation with the inter- sarcostylic fluid spaces. Presumably there exist between the metafibrils capillary interfibrillar canaliculi. When the muscle contracts, the predominantly crystalloidal medial dise (Q-dise) of each metafibril of the sarcostyle divides along the midline (mesophragma level) and the resulting halves move in opposite directions to fuse with similar halves, from successive sarcomeres, along the terminal telophragmata, thus forming contraction bands. The contraction bands accordingly represent discs of predominantly crystalloidal composition, and a reversal of strata (striations) as regards the deeply staining crystalloidal substance of the relaxed sarcostyle has occurred during contraction. ee eee STRIPED MUSCLE STRUCTURE iat The problem of muscle contraction, therefore, resolves itself, in the final analysis, into a physicochemical explanation of the shortening and thickening of the sarcomere in relation to the movement of a medial mass of crystalloids (electrolytes) through the terminal colloidal segments against the telophragma bound- aries. It is here assumed that the movement of crystalloids among colloids is the cause, not simply the accompaniment, or the result, of contraction. The solution of the above-stated problem involves also an explanation of why, during the original determination of the stratified condition of the sarcostyle, the crystalloids, presum- ably entering terminally via the telophragmata, take a definite median position. The attempt at such explanation must first be disposed of. In regard to this aspect of the complete prob- lem, we are actually dealing with a colloidal compartment, a hydrogel of myosin, bounded on the side where the erystalloidal substance presumably enters by a relatively coarse telophragma, at the opposite end where it is deposited, by a relatively delicate mesophragma. When crystalloids mingle with a col- loid, the molecules of the latter suffer a change of surface elec- trical charges, and it may be assumed that the crystalloidal particles or ions are repelled (or perhaps simply passively carried by fluids, due to the fusion of collodial particles behind thus propelling fluids forward) to the limit where they are held by the mesophragma and the adjacent mass of electrolytes.2. The electrical condition of the now polarized sarcomere may now be considered to be in stable equilibrium in the resting fiber. What- _ ever the original form or state of aggregation of the colloidal particles, the passage of the ecrystalloidal particles, and their The manner of origin of the initial stratification may perhaps be com- parable to that of the so-called Liesegang phenomenon of colloidal chemistry, which phenomenon occurs when a gel containing a substance in solution is treated with a second solution capable of reacting with the solution in the gel; e.g., when to a test-tube partly filled with 1 per cent agar gel containing ealeium chloride is added a solution of sodium carbonate. The calcium ecar- bonate formed by the interaction is deposited in strata throughout the agar cylinder (vide Hatschek, “An introduction to the physics and chemistry of colloids,” p. 73, P. Blakiston’s Son & Co., 1919). 112 H. BE. JORDAN segregation in the future Q-disc, must be considered to cause the assumption of an ellipsoidal form of the colloidal particles with the long axis parallel to the length of the sarcostyle. Such original elongation of the colloidal particles may cause a certain amount of elongation or longitudinal growth of the prefunctional sarcostyle. A possible original change of form, under the in- fluence of the entering crystalloids, from an ellipsoidal form (with long axis of colloidal particle parallel to length of fiber) to a spherical shape, would offer the same basis for a future con- traction of the sarcomere, if we assume that the formation of the contraction band involves a change of form of the colloidal particles (due to alteration of surface tension) from a spheriodal form to an ellipsoidal form in which the long axis of the colloidal particle is placed at right angles to the long axis of the sarcostyle. All things considered, however, the former alternative seems the more probable. We may now proceed to consider contraction in the histologi- cally mature sarcostyle. Contraction is initiated by a nervous stimulus. The latter may be regarded as a wave of negative electricity. We may suppose that the negative charge enters the sarcomere at the level of the more delicate mesophragma. This disturbs the electrical potential and causes repulsion of the electrolytes; that is, the charged ions are made to travel from the level of the mesophragma through the adjacent colloidal area against the telophragmata, where contraction bands are formed. The movement of the electrolytes among the colloidal particles causes a change of surface energy, hence of surface ten- sion, by reason of the discharge of surface electrical charges and in consequence a change of shape of the colloidal particles. If we assume that this change of shape is one of change from an ellipsoidal form (oriented in the longitudinal plane) to a sphe- roidal shape, the shortening and thickening of the constituent sarcomeres of the sarcostyles, and thus muscle contraction, is accounted for. The formation of the contraction band again results in a condition of stable electrical equilibrium, which latter is again upset when the particular nervous stimulus is interrupted, and a movement of the electrolytes is started in the opposite direction, resulting thus in the characteristic strati- STRIPED MUSCLE STRUCTURE 113 fication and the electrically stable condition of the sarcostyle in repose. If this is in fact the central significance of the deeply staining Q-substance, its variable relative width in different fibers of the same muscle becomes intelligible: its relative quan- tity within certain limits may not be a fundamentally essential requirement for adequate function of the contractile mechanism; all that may be required is a certain minimal amount and limi- tation within certain maximal amounts. Furthermore, the ap- parent relative amount of the Q-substance may be largely inci- dental to the degree of its concentration. Since I have previously deduced and supported the hypothesis that intercalated dises, characteristic of heart muscle, and occa- sionally found also under certain conditions in voluntary striped muscle,’ represent in essence modified irreversible contraction bands, it seems demanded in this connection that the formation of these inter¢alated discs be also explained consistently with the above outline of muscle contraction. During muscle con- traction lactic acid is formed. When a muscle is made to func- tion to exhaustion, the amount of lactic acid is excessively in- creased. Acid has a precipitation or coagulative effect upon colloids and upon mixtures of colloids and crystalloids. Inter- calated discs would thus find their explanation, in accordance with the above scheme of contraction, in the supposition of the production of a relatively excessive amount of lactic acid under certain conditions, sufficient to effect a precipitation, that is, an irreversible coagulation, of a part of, or an entire contraction band. The above-outlined physicochemical explanation of muscle contraction is in essence very similar to that presented by Pren- ant, Bouin, and Maillard. These histologists describe contrac- tion as an electrocapillary phenomenon. ‘The cause of the short- ening and thickening of the sarcomeres they also locate in a change of shape of the ultimate colloidal particles of the intra- fibril sarcoplasm, following an alteration of electrical potential of opposite surfaces of contact of adjacent particles. But these authors do not carry their analysis and interpretation to the point above indicated with regard to the first appearance and the segregation of the erystalloids within the primitive colloidal 114 H. E. JORDAN sarcomere, nor do they recognize a movement of crystalloids during contraction from the mesophragma to the telophragma, nor do they locate the cause of change of shape of colloidal par- ticles specifically in the surface of contact between electrolytes and colloidal particles. Similarly Lillie’s'® explanation of muscle contraction has a close resemblance to our hypothesis. However, Lillie conceives of the intimate structure of the sarcomeres in our opinion erron- eously, in that he regards the dim Q-dise as the result solely of a greater concentration, or of a different state of aggregation, of colloidal particles at this level. This alleged constitution presupposes relatively large interstitial fluid-containing spaces in the clear J-dise. Nor does Lillie recognize a movement of dim substance during contraction. He does, however, assume a movement of interstitial fluid from M to Z, but only as an incidental result of the closer aggregation of the ‘colloidal ‘sub- microns’ of the dim dise. Lillie conceives of the energy of con- traction as transformed surface energy of the ultimate structural element or colloidal particle (submicron) composing the fibril gel. The shortening and thickening of the sarcomere is thought to result from the massing of the colloidal particles in the ‘aniso- tropic’ segments, the massing itself resulting from the height- ened surface tension resulting from diminished electrical surface polarization. He regards contraction as similar to reversible coagulation of colloids. This hypothesis, considered in detail, gives no clue for the consistent interpretation of intercalated dises. It is readily conceivable that the conditions here postu- lated might lead to an irreversible coagulation of sarcoplasmic colloids; but such areas of irreversibly coagulated sarcoplasm would be at the level of the mesophragma, according to Lillie’s explanation, and not, as is actually the case, at the levels of the telophragmata. According to our hypothesis, on the contrary, the shortening and thickening of the sarcomere, that is, contraction, results from the change of shape of the ultimate colloidal sarcoplasmic particles following an increased surface tension, the latter result- ing from decrease or disappearance of the surface charges of the STRIPED MUSCLE STRUCTURE 115 colloidal particles accompanying the movement of electrolytes among them from the mesophragma to the telophragma, the movement being initiated by the disturbance of electrical poten- tial of the membranes, primarily of the mesophragma, surround- ing the sarcomere following the passage of nerve stimulus. It must be admitted, however, that a precipitation of colloidal particles by electrolytes would have essentially the same effect of shortening and thickening of the sarcomere as would a change of shape of the particles. But Lillie’s hypothesis permits of no plausible explanation of the dim character of the contraction band. If, as Lillie assumes, the Q-dise of the fibril in repose is ‘dim’ because of a closer aggregation of colloidal particles at this level, and if, as he further assumes, contraction is essentially a matter of a still closer massing of colloidal particles at this level, with a forcing of interstitial fluid into the telophragma borders of the clearer J-segments of the sarcomeres, then the latter areas should become lighter instead of becoming darker, as they actually do become as parts of contraction bands. If the Q-dises are ‘dim’ because of a closer aggregation of colloidal particles here, then the ‘dimness’ of the contraction bands should consistently be explained in the same way; but that the latter are areas of closer aggregation of colloidal particles is in contra- diction to the central idea in Lillie’s hypothesis. Reconcilia- tion of this damaging contradiction can be effected, and the integ- rity of Lillie’s hypothesis maintained, only on the assumption that the Q-disc is dim because of the presence here of an addi- tional darker, more fluid substance, which latter becomes forced against the telophragmata during contraction and here gives the darker color or ‘dim’ appearance also to the resulting contrac- tion band. But when this further assumption has been added to the basic assumptions of Lillie’s hypothesis, we are very close to the hypothesis here urged and supported, namely, that the cause of contraction is located in the final analysis in the fact of a movement of ‘dim’ substance among the colloidal particles of the sarcomere from M to Z. And in view of the demonstra- tion of the segregation of crystalloids in the dim dises (Q-dise and the contraction band) the latter hypothesis would seem to be the most satisfactory alternative. 116 H. E. JORDAN No hypothesis of muscle contraction can of course be satis- factory that cannot be harmonized with the principle of the conservation of energy. We must be able to find within the muscle, sources of energy approximately equal in sum to the amount of energy expended by the functioning muscle; which energies must both be approximately equal to the underlying chemical energy of the metabolic processes of active muscle. The details of the exact relation between the chemical energy of muscle metabolism and the postulated surface-tension energy of the sarcoplasmic particles need not be here considered. The energy of the nerve stimulus need of course be only sufficient to start the initial link in the chain of chemical reactions of the metabolic processes underlying the assumed surface-tension energy of contraction. Lillie'® supports the hypothesis that the contractile energy of muscle is due to changes in surface tension of certain muscle elements by these statements: In contraction the surface tension of these elements is supposedly increased. If this increase of tension is sufficiently great, and the area of the active surface sufficiently large, the transformable surface- energy, which is measured by the product of these two factors, may be sufficient to account for the work done by the muscle in contrac- t100: Thereis . . . good reason to regard the ulti- mate colloidal particles of the fibrils as corresponding to such elements. By their union to form larger particles, as in the general process of col- loid-coagulation, sufficient mechanical energy to account for contrac- tion might conceivably be freed, since the reduction of surface-area in such a process may be very great, implying a correspondingly large transformation of surface-energy (p. 252). In résumé, the gist of our hypothesis involves the following assumptions, which are consistent with the fact of a movement of ‘dim’ substance from the Q-dise to the contraction band dur- ing contraction: The nerve stimulus causes a movement of ions from M to Z effecting a change in shape of the colloidal particles from ellipsoidal to spherical; cessation of stimulus, an instant return of ions from Z to M with a return to the original ellip- soidal form of the colloidal particle; the change in form of the * For a review of the earlier literature touching similar interpretations of mus- cle contraction, the reader is referred to Lillie’s paper and to Schaefer's text- book (p. 189). STRIPED MUSCLE STRUCTURE 117 latter being the result of an alteration of surface tension following alternating increase and decrease of surface electrical charges under the influence of the reversal of the direction of the current of action and the moving electrolytes. The histologic data relative to the intimate structural changes in contracting muscle above given seem in strict accord with the conclusion that the source of the contracting energy of muscle resides in alterations of surface tension in the colloidal particles of the ultimate muscle fibrils. My conception of the physico- chemical process in ultimate detail differs from that of Lillie in essence only in that Lillie interprets contraction as the result of an aggregation or union (resembling reversible coagulation or precipitation) of the colloidal particles mainly in the Q-disc, with expression of interstitial fluid into the J-disc, following increase of surface tension due to decrease of surface electrical charges; while I view the histologic data (supplemented by the micro- chemical data of Macallum and of Menten) as indicating an actual movement of soluble crystalloids (electrolytes) from the mesophragma to the telophragmata, which movement of electrolytes may be interpreted as the chief factor in effecting an increase of surface tension of the colloidal particles and so altering the shape of the particles, which alteration of shape, rather than a massing of the particles, effects a shortening and thickening of the sarcomeres. SUMMARY 1. The relatively very coarse sarcostyle of the wing muscle of the wasp is strictly homologous with the myofibril of vertebrate striped muscle. Both varieties of fibrils consist of bundles of extremely minute constituent metafibrils. The wasp’s sarcostyle has an enveloping layer with the properties of an osmotic mem- brane, the sarcostylic membrane. 2. The structural changes exhibited by a striped muscle fiber during contraction are the result of similar changes in the con- stituent. metafibrils. The fundamental and essential change con- THE ANATOMICAL RECORD, VOL. 19, NO. 2 118 H. E. JORDAN cerns the equal division at the level of the mesophragma, and the subsequent movement, of the more deeply staining sub- stance of the Q-dise, against the terminal telophragmata of the sarcomere, where are formed the contraction bands. 3. The salient histogenetic steps occur in the following order: The myoblasts of the imaginal disc differentiate from ectoderm; the first-formed myofibrils are homogeneous; the telophragmata precede the appearance of the Q-dises; the latter are at first very delicate and only gradually acquire their typical definitive width. The sarcosomes appear only relatively late, shortly before func- tional activity of the wings. 4. The order of development of the two chief cross-stripes, the connecting Z-membranes and the Q-dises, explains the exact horizontal alinement of similarly modified levels of the constit- uent fibrils of a striped muscle fiber. The telophragmata prob- ably function chiefly as the pathways along which the deeply staining substance of the Q-dises first enter the sarcostyle, and along which metabolic products pass to and fro between the sarcostyles and the interfiber tissue spaces. 5. In the effort to disclose the ultimate physicochemical bases of muscle contraction, we may legitimately and confidently con- fine ourselves to the structure of the sarcomere of the relatively coarse myofibril (sarcostyle) of the wasp’s wing muscle. The fundamental factor in muscle contraction is located in the move- ment of the deeply staining substance of the Q-dise against the telophragmata in the formation of contraction bands. The con- comitant shortening and thickening of the sarcomeres is inter- preted as the result of a change in shape, from ellipsoidal to spherical form of the ultimate colloidal particles of the intra- fibril sarcoplasm, following an increase of surface tension of these particles (submicrons) resulting from a decrease of surface electrical charges due to the passage of electrolytes (crystalloids of the deeply staining substance of Q) among the colloidal particles. 15 16 STRIPED MUSCLE STRUCTURE 119 LITERATURE CITED Buuiarp, H. H. 1916 On the occurrence and physiological significance of fat in the normal myocardium and atrioventricular system (bundle of His), interstitial granules (mitochondria) and phospholipines in car- diac muscle. Am. Jour. Anat., vol. 19, p. 1. Gopiewsk!, E. 1901 Ueber die Entwicklung der quergestreiften musku- lésen Gewebes. Krakauer Anzeiger (cited from Heidenhain). Herpennain, M. 1911 Plasma und Zelle, S. 641-648. Herpennain, M. 1913 Ueber die Entstehung der quergestreiften Muskel- substanz bei der Forelle. Beitrige zur Teilkérpertheorie, Il. Arch. f. mikr. Anat., Bd. 88, S. 427. Jorpan, H. E. 1917 The microscopic structure of striped muscle of Limu- lus. Pub. no. 251, Carnegie Inst. of Wash., p. 273. 1917 Studies on striped muscle structure. III. The comparative his- tology of cardiac and skeletal muscle of scorpion. Anat. Rec., vol. 13, pei 1919 Studies on striped muscle structure. IV. Interealated discs in voluntary striped muscle. Anat. Rec., vol. 16, p. 203. 1919 Studies on striped muscle structure. V. The comparative his- tology of the leg and wing muscles of the mantis, with special reference to the N-dises and the sarcosomes. Anat. Rec., vol. 16, p. 217. 1920 Studies on striped muscle structure. VI. The comparative his- tology of the leg and wing muscles of the wasp, with special reference to the phenomenon of stripe reversal during contraction and to the genetic relationship between contraction bands and intercalated discs. Am. Jour. Anat., vol. 27, p. 1. Linum, R. 8S. 1912 The physiological significance of the segmented struc- ture of the striated muscle fiber. Science, vol. 36, p. 247. Luna, E. 1913 Sulla importanza dei condriosomi nella genesi delle myo- fibrille. Arch. f. Zellf., Bd. 9, S. 458. Macauium, A. B. 1905 On the distribution of potassium in animal and vegetable cells. Jour. Physiol., vol. 32, p. 95. Menten, Maup L. 1908 The distribution of fat, chlorides, phosphates, potassium and iron in striated muscle. Tran. Canadian Institute, vol. 8, p. 403. PreNANT, A., Bourn, P., BT MaAILLARD, L. 1904 Traité d’Histologie, T. 1, p. 440. Scuagrer, BE. A. 1912 Textbook of microscopic anatomy. Longmans, Green & Co. Tuuuin, I. 1915 Ist der Grundmembran eine konstant vorkommende Bil- dung in den quergestreiften Muskelfasern? Arch. f. mikr. Anat., Bd. 86, 8. 318. EXPLANATION OF FIGURES re f The drawings were nade from sections of tissue fixed in 10 per cent formalin. The sections were cut at 4u, and stained with iron-hematoxylin. With the ex- ception of figure 13, the magnification of the drawings is 1300 diameters. The section from which figure 10 was made was lightly counterstained with eosin. a PLATE 1 EXPLANATION OF FIGURES 1 a. Longitudinal section of myoblast immediately after separation from the imaginal disc. The originally single nucleolus has become divided in antici- pation of the ensuing direct division of the nucleus. 6, Three slightly older, now multinucleated myoblasts, in process of fusion to form a muscle fiber. Deli- cate peripheral myofibrils are faintly discernible. The specimen from which these drawings were made was at the latest larval or earliest pupal stage; wing pads were present, but the legs had not yet appeared. ; 2 a,b andc. Transverse sections of three successively older myoblasts from __ the same specimen as figure 1. Sections a and b correspond to a and b of figu c represents a slightly older stage, cut at the level of lateral fusion as indica by the two radially adjacent nuclei. c.t., an interfiber connective-tissue cell in — early stage of metamorphosis into a fat-cell. . ‘ 3 Transverse section of later wing-muscle fiber from same specimen. The nuclei are now very numerous and scattered apparently at random. The myo- fibrils are uniformly distributed throughout the sarcoplasm and appear as darker dots in transverse sections. c.t., a connective-tissue cell. The latter ee numerous and completely fill the wide interfiber spaces. 4 Longitudinal section of fiber like the one of figure 3. The homogeneous myofibrils are conspicuous between the columns of nuclei. The interfiber spaces are approximately of the width of the diameter of the fibers. These spaces are completely filled with short fusiform and polyhedral connective-tissue cells. 5 Transverse section of older fiber, from white pupa (with wings and legs). The fibrils have become much coarser and appear radially disposed along the left border. 120 STRIPED MUSCLE STRUCTURE PLATE 1 H. E. JORDON PLATE 2 EXPLANATION OF FIGURES 6 Longitudinal section of fiber like that of fig. 5. The nuclei are long narrow elements dividing directly into smaller nuclei. Among the homogeneous coarse myofibrils are scattered smaller irregular granules. There is as yet no indication of telophragmata or other stratification in the fibrils. 7 Peripheral portion of older fiber in transverse section, showing the coarse myofibrils (sarcostyles), a peripheral nucleus, and the sarcolemma. Sarcosomes have not yet made their appearance. The section is of a later pupal stage (gray pupa). 8 Portion of adult wing-muscle fiber in transverse section, showing the coarser myofibrils and six ineluded irregular sarcosomes. 9 a, b, c, d and e. Three successive stages in the later development of the myofibril, from a longitudinal section of the thoracie (wing) muscles of a gray pupa (same as fig. 7). @ shows two adjacent fibrils in which only the Z stripe (telophragma) has appeared. This stripe stains very intensely at this stage. In fibril b the Z-stripe is faint, and a deeply staining but thin Q-dise has appeared. In ¢ the Q-dise has become much thicker. d and e are at the same stage of de- velopment, but in d the Q-dise has become bisected and an H-dise has in con- sequence appeared, and in e the metafibrillar constituent elements of the sarco- style have become conspicuous. 10 Longitudinal section through region of attachment of muscle to epider- mis. The nucleus lies in the ‘tendinous’ portion of this connection. This ten- dinous portion stains much more deeply in a very dilute eosin counterstain than the muscle. At the levels where the sarcostyles break up into the ‘tendon fibrils’ the telphragmata disappear. 11 Small area of longitudinal section of wing-muscle sarcostyles of older (black) pupa. Between the sarcostyles are single rows of small oval sarcosomes, generally two to a sarcomeric interval. 12 Portion of a transverse section of a fiber like that of figure 11, including one nucleus. Many of the apparently oval sarcosomes are now seen to have lateral wing-like processes. Compare with figures 7 and 8. 13 Sarcostyles of definitive wing muscle of adult wasp at four successive stages in contraction. Fibril a is in repose; b is in an early, c in a later stage of contraction; d represents a contracted fibril with almost fully formed, double contraction band. *? 122 E2 AT PL RE STRUCTUI ED MUSCLE CP RIP H. B. JORDAN TERE GPE) © Cr (UAE ARE a eo G HREM © ee ea eee \ hab tol ee eae i toh i] vo ~ at Resumen por la autora, Kaethe Weller Dewey, Universidad de Illinois. Contribucién al estudio del sistema linfatico del ojo. La autora considera a la coloracién vital como el mejor medio para demonstrar los capilares linfaticos y espacios linfaticos del ojo, del mismo modo que los de otras partes del cuerpo. Las células endoteliales que tapizan estos canales tienen la propiedad de tefirse con el colorante vital. Los resultados de los experi- mentos con la parafenilendiamina hacen resaltar las diferencias entre los espacios de los tejidos y los espacios linfiticos, el plasma y la linfa propiament edicha. Las observaciones llevadas a cabo mediante el tenido vital con referencia a su significacién presunta en el sistema linfatico no estin en contradiccién con los hechos anatémicos reconocidos. Aceptando el hecho de que Jas células endoteliales vitalmente tefidas denotan la presencia de canales linfaticos, se comprueba la ausencia de dichos canales en la cérnea, mientras que la conjuntiva los posee abundantes. La esclerética posee muy pocos capilares linfaticos, que a veces faltan en ab- soluto; pueden acompafiar a los vasos sangufneos que la atra- viesan. ‘T'ampoco existen en la retina. La coroides los presenta principalmente en los coriocapilares. La glindula lagrimal, el tejido orbitario y los pirpados presentan abundantes capilares linfiticos. No existen en el cartilago tarsal de los pdrpados. Las células vitalmente tefidas son mas abundantes en el cuerpo ciliar y, especialmente, en los procesos ciliares, que en cualquier otro parte del ojo. Esto coincide probablemente con mayores actividades funcionales, tales como la intensa participacién en la seerecci6n del fluido intraocular. El iris esta provisto de es- casos capilares linfaticos, a pesar de su rica irrigacién sanguinea. Esto indica que tal 6érgano no desempefid las mismas actividades funcionales que el cuerpo ciliar. Translation by José F. Nonidez Cornell University Medical College, N. Y. AUTHOR'S ABSTRACT OF THIS PAPER ISSUED BY THE BIBLIOGRAPHIC SERVICE, MAY 24 A CONTRIBUTION TO THE STUDY OF THE LYMPHATIC SYSTEM OF THE EYE KAETHE W. DEWEY Research Laboratory of the College of Dentistry, University of Illinois THREE FIGURES In view of the great interest which evidences of an etiological relationship between infectious processes about the teeth and pathological conditions in other regions are receiving in recent years, clinical and anatomical investigations vie with one another in furnishing the necessary scientific foundation for more or less empirical conclusions. Relations between certain affections of the eye and diseased teeth have been recognized since the remotest ages, but reliable reports of actually observed transmissions of pathological processes from the teeth to the eye are all of a rela- tively late date. The number of these published reports is not inconsiderable.! Little, however, is yet known concerning the routes of transmission that could in any way be considered as positive and final. The dental origin of cases of the so-called dental eye fistula, orbital phlegmon, and abscesses is revealed chiefly through the fact that the eye conditions either promptly disappeared with treatment of the involved teeth or that they developed upon the extraction of a tooth with or without involve- ment of the maxillary sinus. The traveling of the pus from dis- eased teeth to the orbit, as, for example, in phlegmon, has often been represented as being per continuitatem along the outer sur- face of the maxilla over the orbital border. Frequently a trans- mission by way of the veins is assumed, and also a few casual suggestions occur in the literature that the processes may pro- gress by way of the lymphatics. The latter route, however, is probably more important and much more frequent than the 1A report of clinical observations along these lines will be published in Archives of Ophthalmology, July, entitled ““Affections of the Eye from Diseased Teeth.’’ 125 126 KARTHE W. DEWEY scanty and incomplete statements concerning it would make us believe. The demonstration of direct communications between the lymph supply of the dental region and that of the eye is obviously difficult. In previous experimental work for the demonstration of the lymphatics of the dental pulp and the peridental mem- brane! ? indications of extensive anastomoses in the lymph-sup- ply of these two regions were sometimes incidentally obtained. In injections by the Gerota method of Prussian blue into the gum tissue the fluid was not only forced through the bony tissue of the jaw into lymph-vessels of the peridental membrane, but sometimes deep and superficial lymph-vessels of the infraorbital region were also injected. The looseness of the orbital tissue makes injections in the region of the eye unsuitable for purposes along these lines: the injection mass will follow the direction of the least resistance and fill the loose tissue of the orbit. This oecurs also in injecting the fluid through the infraorbital fora- men, which is the most accessible place for reaching lymph-ves- sels in either direction to the eye as well as the dental region. Until recently our knowledge of the lymph-supply of the eye region was very limited and it is still quite incomplete with re- gard to the lymphatic system of the eye proper. Bartels,? in 1909, writes: ‘‘ Nowhere besides in the lids and the conjunctivae have genuine lymph-vessels been surely demonstrated, while we may say that it has been shown with a probability bordering on certainty, that in the cornea, the lens, and the vitreous body they are completely lacking. In fact, we need not look for a current of fluid in a stable optic apparatus. It is quite different, however, in the other parts of the eye which constantly have to perform most important work and where therefore correspondingly active metabolic interchanges must be assumed a priori. They have not yet been demonstrated, however.” A lymphatic apparatus of the orbit has been demonstrated by Birch-Hirsehfeld.‘ That the existence of such a system may be presupposed has been claimed before him by some writers who are unwilling to consider the lymphangiomas of the orbit as heteroplastic formations; the occurrence of these speaks for the LYMPHATIC SYSTEM OF THE EYE 127 presence of lymphoid tissue in the orbit even if in such minute amounts as to escape microscopical observation. By methods which, according to Birch-Hirschfeld, produce an increased lymph secretion or lymph stasis resulting in dilatation of the lymph- capillaries, this author believes he has seen distinct lymph spaces in the orbital tissue—in the lipoid tissue, the lacrimal gland, between the muscles, and in the neighborhood of the optie nerve and the periosteum. With his methods he could not demon- strate the direction in which the lymph flows off nor a connection with any lymph-gland. He believes, however, we may assume that communication exists between these spaces and the lymph- vessels of the nose, and that there is a connection between the orbital lymph system and that of the surrounding regions through the perivascular spaces about the vessels passing through the superior and inferior orbital fissures. Histologically, the demonstration of the minute lymph-vessels of most organs is very difficult, if not altogetherimpossible. Post- mortem, they are practically virtual spaces and the endothelial cells lining them are in general indistinguishable from the slender nuclei of the surrounding connective-tissue cells. In order to distend them and thereby render them more amenable to micro- scopic study Birch-Hirschfeld employed a drug which is known in pharmacology and toxicology to produce chemosis and edema of the orbit, exophthalmus and increase of the intra-ocular pres- sure. This drug is paraphenylendiamine hydrochloride. He also made use of dionin, small pieces of which he introduced into the orbital tissue. The action of this drug is to cause dilatation of the capillaries and increase of the lymph excretion, and this is especially well demonstrated about the eye. Paraphenylendi- amine, according to him, produces stasis of the lymph, and an increase of the secretion of. the lacrimal gland, of the mucous secretion of the conjunctiva and the salivary glands. If a large dose is given, the edema of the orbit extends also to the face and the neck. Edema of the glottis is the final cause of death. Similar observations are reported by Grunert,> Matsumoto,® Puppe.? The spaces in the orbital tissue and those in the lac- rimal gland which Birch-Hirschfeld found dilated and filled 128 KAETHE W. DEWEY with fluid after diamine poisoning are believed by him to be lymph-spaces, and he states that in some of the larger and medium-sized spaces he found a distinet endothelial membrane. These statements by Birch-Hirschfeld seemed to me of ex- treme importance. If the observations could be verified and his conclusions shown to be right, the use of paraphenylendiamine should enable me to prove the correctness of a view obtained from previous experimental work on vital staining, which, in the ab- sence of more positive proofs, I could express only suggestively.® Vital staining, I stated, may be the means of demonstrating the lymph-channels of origin in most organs of the body by exhibiting their endothelial cells which have an affinity for vital stains. Granting the correctness of Birch-Hirschfeld’s observations, para- phenylendiamine should be a valuable aid in such investiga- tions by demonstrating a lumen in such endothelial-clad lymph- channels. I tested this drug on two dogs, two eats, ten rabbits, and ten frogs. The larger number of these animals were injected with lithium carmine previous to their treatment with the diamine poison. The results of these experiments will be reported in detail in another paper as a question dealing largely with pharma- cology. They were disappointing to the extent that they con- tributed nothing to the main purpose of this study: the micro- scopical study of the tissues in diamine poisoning failed to reveal what I had expected to find. The dilated spaces in the edematous tissues are not lined with vitally stained endothelial cells. Most of them are simply surrounded by delicate fibers without any cellular elements; occasionally a slender nucleus may be seen in this wall, resembling as much the nucleus of a connective- tissue cell as that of a flat endothelial cell. Vitally stained cells may be seen near these spaces, but never so near as to justify the impression that they form any part of the wall. I am, however, not inclined to believe that these spaces are lymph-spaces, as Birch-Hirschfeld does, but consider them simply as tissue spaces and distended meshes in the connective tissue, nor do I regard the fluid as lymph proper, but as a serous effusion, plasma from the blood-vessels, LYMPHATIC SYSTEM OF THE EYE 129 Sections from the edematous subcutaneous tissue of the face and over the lower jaw in rabbits show that all this tissue is split up into innumerable spaces and slits filled with fluid, to regard all of which as lymph-spaces, potential or actual, would not be reasonable. One of the chief effects of the drug seems to be on the blood-vessels, perhaps irritating the endothelial wall of the capillaries, and thereby rendering it more permeable. This is particularly noticeable in muscles of the eye. The bundles and fibers of the muscles are separated more than is normal; the fibers of the connective tissue in these intermuscular spaces are slit apart and all these widened meshes and spaces are filled with fluid, which stains well with hematoxylin. The muscles: are richly supplied with blood-capillaries which wind in and out about the muscle fibers. But we fail to see any lymph-capillaries with a perceptible lumen; if they are present, as is to be presumed, they are at any rate not dilated. The muscles about the eye, like some muscles of the face, show a brown discoloration after diamine poisoning. It is an interesting observation that, while the anatomical and clinical effects of paraphenylendiamine are so widely different in the different species of animals, and even in animals of the same species, they all have one feature in common, viz., this brown discoloration of certain muscles of the face. Some of the writers who have studied the effect of this drug claim that the cause of the edema is to be sought for in the lacrimal gland. On the other hand, Puppe believes that the stasis edema is perhaps due to the formation of thrombi in the veins, and Kunkel? also assigns to the blood-vessels and the blood a greater significance for the development of the intoxication edema. My observations agree with the latter view. On account of the extensive anastomoses of lymph-vessels obstruction to the outflow of lymph does not readily occur. We may conceive of the action of paraphenylendiamine as follows: in subcutaneous injections the drug enters the lymph channels, thence it is carried into the blood, where it irritates the walls of the blood-vessels, possibly having an injurious effect on the en- dothelial cells of the capillaries. Transudation of the plasma occurs very rapidly, the fluid filling all the tissue spaces and sep- 130 KAETHE W. DEWEY arating the tissue elements. The function of the endothelial cells of the lymph-capillaries being not simply one of absorption of such free fluid, but probably one of a selective action, of an interaction of metabolic processes, the fluid is not taken up and earried off rapidly enough with the result that stasis-edema develops. The formation of lymph is not, as was formerly believed, a mechanical process, i.e., one of simple filtration and diffusion, but is work essentially done by the organs themselves. The mechanical theory has been superseded by the cellular-physio- logical theory. The endothelial cells of the lymph-capillaries probably play a chief part in these processes. Although these capillaries end or begin as absolutely closed culs-de-sac, and the presence of a continuous endothelium represents a barrier be- tween them and the surrounding connective tissue, “the rela- tions between the vascular cavity and the connective-tissue spaces remain very close,” as Delamere" states, ‘‘and cellular immigra- tion and osmotic exchanges may always take place and the cap- illaries fulfill their function of drains, and, if the observations of Renaut are confirmed, may even act as selective drains.” : ‘The value of paraphenylendiamine in conjunction with vital staining is, in my opinion, this, that it illustrates and supports the theory of a difference between spaces filled with tissue fluids and real lymph-spaces and lymph-capillaries, which constitute the channels of origin of the lymph system. Bartels,’ it is true, is rather skeptical as to any fruitful research along these lines. To him this much-debated question is largely a philosophical one; he writes: ‘‘The question concerning the origin of the lymph system and the development of the lymph stream from the flow of the tissue juices is a purely philosophical and not an anatomical one. This question and that of the endings of the blood-vessels should be eliminated from anatomical discussions.” Neverthe- less, the contemporary conception of the origin of the lymph system is emphatic in upholding the theory of an independence of the lymph-spaces and the tissue spaces, and of the absence of open communications between them, as also of a difference be- tween plasma from the blood-capillaries and lymph proper. LYMPHATIC SYSTEM OF THE EYE 131 This fact is also illustrated by the observation that injections into the submucous cellular tissue of the skin may fill the tissue clefts and tissue spaces and produce edema, but not fill the lymph- vessels. Similar observations may be made in injecting the blood-vessels with carmine gelatin; when the injection is con- tinued under high pressure for some time, it may happen that the fluid portion of the injection mass is pressed through the stretched capillary wall and fills the tissue spaces producing edema without entering into lymph-vessels. In fact, I have never been able to fill lymph-vessels by way of the blood-vessels. As a result of my observations from the experiments which I have made, I have come to the conclusion that the vitally stained cells within the connective tissue of organs represent the endothelial cells lining the capillaries of origin. By several writ- ers the view has been expressed that the connective tissue evi- dently plays a much more important réle than that of being simply a supporting stroma for other parenchymatous tissue, and this impression is imparted to them chiefly by the presence of these peculiar vitally staining cells which have been called rhagi- ocrines, resting wandering cells, macrophages, pyrrol cells, his- tiogenic wandering cells, ete. The ability of these cells to take up the vital stain apparently coincides with specific functional prop- erties; they have chiefly been alleged with secretory functions, and Renaut! writes of the connective tissue as ‘‘the largest of the glands with an internal secretion which exists in the body of vertebras.”” On the other hand, Ehrlich points out the extraor- dinary adaptability of the cellular elements of this tissue and that a specific modification adjusted to definite functions of the organ which it supports, cannot be considered as in any way astonishing. But nowhere in the literature have I found even a suggestion that these specific cells may belong to the lymphatic apparatus. Yet we know that everywhere in the body the struc- tures which constitute the beginning of the lymph system are embedded within the connective tissue. It is only reasonable to assume that the endothelial cells which form the sole wall of these delicate primary lymph-channels (lymph-spaces and lymph- capillaries) are more than a lining; that they are rather the chief 132 KAETHE W. DEWEY agents in taking up the ambient tissue fluid or plasma from the blood-capillaries after it has been altered in its contact with the cells. This process is more than one of simple filtration, or even of a selective filtration; it is a process of vital elaboration, in- cluding probably secretion and excretion. Furthermore, as the plasma differs from the lymph partially as a result of the activi- ties of the blood-capillary endothelium, so, too, the lymph coming from these capillaries is again modified when passing through the lymph-gland; for there are distinct differences in the lymph enter- ing the lymph-gland and that passing out of the gland. The latter shows an increase in the cellular elements; the tendency to fibrin formation and coagulation is more rapid, and the proportion of the water is diminished. This modification of the lymph is likewise the work of the endothelium of lymph-capillaries, for the lymph-vessels entering the lymph-gland break up into capillaries, thus forming a true portal lymph system. Bearing this in mind, it is most significant that this whole process of the formation of a second capillary network and of a modification of the lymph by its endo- thelium is signalized, as in the endothelium of the lymph-capil- laries of the connective tissue, by the property of the cells to take up the vital stain. We have here, therefore, the striking phenomenon that at the source of the lymph system there are specifically functionating endothelial cells of capillaries, and that these alone have the power to take up the vital stain. This property is absent in the endothelial cells of the lymph-vessels arising from the capillaries, but is present again, and in a most marked degree, in the endothelial cells of the capillary network within the lymph-gland; these are most brilliantly stained, while the afferents and the efferents of lymph-glands have no vitally staining endothelial cells. Evans"? also has pointed this out as a very striking phenomenon, There are some other general observations on vital staining, agreeing well with anatomically established facts, to which I would call the attention. It is recognized that the lymphatics are unequally distributed throughout the organism, seemingly in an arbitrary fashion. The same observation is made in regard to vitally stained cells. Lymph-vessels are considered to be LYMPHATIC SYSTEM OF THE EYE 133 absent in a few organs and tissues; these are the same organs in which these cells are lacking. They are however, present in cer- tain regions where lymph-vessels have not yet been demonstrated because of the almost unsurmountable difficulty in injecting them, but where they may reasonably be assumed to exist. The character of these cells has been interpreted variously; but the name of resting wandering cells seems to be the least fitting, for the most striking feature about them is the stability which characterizes their occurrence, their distribution, their arrangement, and their number. They are invariably absent or present in the same locality and invariably scanty or abundant in the same region. The constant recurrence of these features gives a strong impression that these cells are stationary and that they are part of some definite, functionating apparatus. As to the eye, the occurrence of the same unequal distribution in the various tissues is striking. Schnaudigl"® has studied the effect of vital staining on the eye and made observations concerning the occurrence of vitally stained cells which are on the whole in accordance with my own. They are as follows: the lens is devoid of vitally staining cells. No such cells are found in the cornea, but the conjunctival tissue overlying the corneal tissue shows such cells in large numbers. Occasionally a long, slender, vitally stained cell is seen to extend from the conjunctiva into the cornea. The sclera contains such cells in secant number; it is not quite clear whether they belong to the tissue proper or whether they accompany the vessels traversing the scleral tissue. The cells are quite numerous in the sclera and corneal conjunctiva and in great abundance in the limbus conjunctivae. The iris is very poorly provided with them; a cell is found here and there in the region toward the posterior chamber. This striking relative deficiency of the iris in vitally staining cells apparently was not noticed by Goldmann who made the most extensive studies of vital staining with refer- ence to internal and external secretions. But the statements of his findings in the eye are so brief that we hardly need discuss this difference in our observations. Assuming that these cells denote the presence of lymph-capillaries, the extreme scarcity of such THE ANATOMICAL RECORD, VOL. 19, NO. 2 134 . KAETHE W. DEWEY channels in an organ which is well supplied with blood-vessels is surprising, for we may admit with some of the best authorities in anatomy that lymph-vessels may be supposed to exist wherever there are blood-vessels. This unaccountable scarcity of vital staining cells in the iris is the more striking because the region which adjoins it is unusually rich in vitally staining cells, namely, the ciliary body and chiefly the ciliary processes. The cells are in proportion more plentiful here than in any other part of the eye. They are arranged along the blood-vessels, from which, however, they are always some distance removed. They are pres- ent inall the processes; they are always in abundance and they are always arranged in the same way. When the injections of the staining fluid have been continued for some time these cells are very large and the granules are very coarse; in the iris or sclera they remain small and slender, an observation to which also Schnaudigl calls the attention. This author believes that these cells have an almost dangerous affinity for the staining substance; they are very vulnerable and show the injurious effect of the dye after prolonged contact with the staining fluid. He also believes that this affinity for the dye correlates to specific functions and that these consist perhaps in more than the secretion of the aqueous humor. From the root of the ciliary processes the cells are observed to occur in small number along the subjacent inner layer of the ciliary body; the deeper region, facing the sclera, is scantily supplied with these cells and resembles the iris in this respect. In the choroid, cells are found chiefly in the choroio-capillaris. There are none in the retina. The endo- and perineural tissue contains vitally stained cells. The loose orbital tissue is relatively poor in these cells. The muscles of the eye show the cells in the interfascicular and interfibrillar tissue, gen- erally in the neighborhood of the blood-vessels. They seem to be in closer relationship to the blood-capillaries than, for example, in the ciliary processes; they often seem to spin around the ecap- illaries while these again wind about the muscle fibers. In the laeri- mal gland they occur in the interacinous tissue and the connec- tive tissue surrounding the glandular structures. The lids and the nictitating membrane are well supplied with them; they always LYMPHATIC SYSTEM OF THE EYE 135 occur in the same arrangement and the same distribution. The cartilage is absolutely free from such cells. If we are to admit the view that these cells represent the endo- thelium of lymph-capillaries, we recognize that these findings cor- respond quite well with what we actually know or may reasonably presume concerning the lymph supply of the different parts of the eye. Until recently our knowledge of the lymphatic system of the eye as of that of the dental region was very limited. I will sum up the most essential anatomical data which enter into the frame of this study. The most important of recent work on the lymphatics of the eye is that of Most. His results showed, in brief, the following: The conjunctiva of the lids and the eyeball contain very delicate but dense networks of lymph-vessels. At the free border of the lids they pass over into those of the skin of the eyelid. The lymph-vessels from these two networks are divided into super- ficial and deep ones, chiefly according to whether they arise from the outer skin of the lid or from the conjunctiva; a sharp separa- tion is not possible since both regions communicate with each other. The superficial vessels are apparently finer and less nu- merous; they course in front of the orbieularis muscle and in the superficial portions of the subcutaneous fatty tissue and only in the neighborhood of their regional glands do they pass into deeper regions. The deeper vessels form many anastomoses in the deep cellular tissue of the lids and then pass on peripherally behind the orbicularis muscle. The superficial as well as the deep vessels are divided into a lateral and a median set; they empty into the submaxillary lymph-glands. The superficial lateral vessels originate chiefly in the skin of nearly the entire upper lid and about the outer half of the lower lid. Their first and chief regional gland is a typical gland situ- ated superficially in the parotid gland at the level of the external auditory canal. From this gland vessels go to other deeper parotid lymph-glands. Only exceptionally do the superficial lymph-vessels empty directly into the deep nodes. One or two lymph-nodes situated at the lower parotid pole and belonging to 136 KAETHE W. DEWEY the group of the superficial cervical glands are also to be consid- ered as regional glands, because they may receive direct affer- ents from those regions of the eye. The deep lateral vessels arise in the conjunctiva of the upper lid and the outer third of the lower lid. The regional glands, besides the superficial typical parotid lymph-nodes, include one or two nodes deeply embedded within the parotid gland itself. The superficial median vessels arise chiefly in the skin of the inner half of the lower lid and that of the inner corner of the eye. Their regional gland is one of the submaxillary lymph-glands, especially that situated mesially of the anterior facial vein. The deep median vessels arise chiefly from the conjunctiva of the inner two-thirds and from the region of the caruncula. They form frequent anastomoses in the lid and pass along the anterior facial vein to the submaxillary glands and chiefly to a gland lat- eral to the one mentioned before. Sometimes this one is also injected. All these lymph-vessels go secondarily to the deep cervical glands situated along the internal jugular vein, at the junction with the facial vein. A direct connection of lymph- vessels of the lids and conjunctiva with these secondary glands could not be demonstrated. Before the vessels of the lids and conjunctiva, and especially the median vessels, enter the parotid and submaxillary lymph-glands they may pass through inter- mediary lymph-nodes of the face (lymphoglandulae buceales sive faciales) situated along the course of the anterior facial vein. The submaxillary lymph-glands receive also the lymph from the outer vessels of the gingiva of the upper and lower jaw, from the inner vessels of the lower jaw, and from the vessels of the peridental membrane of all teeth. No absolutely definite lines, however, can be drawn with regard to their relation to the different groups of teeth. For there are, on the one hand, variations in the number and location of the lymph-nodes themselves; on the other hand, it not infrequently happens that single lymph-vessels from a definite region pass by the regional node into which all the others enter and empty directly into a remoter lymph-node. Another reason for this irregularity is the fact that the vessels from the gingiva form plexuses in the upper and lower mucosal LYMPHATIC SYSTEM OF THE EYE 137 fold of the vestibulum oris, from which lymph-vessels pass out into the lymph-glands. An important path of communication between regions of the eye and the teeth is through the infra-orbital canal with its nerves, arteries, veins, and lymph-vessels. These send branches in either direction. Two small canals, the anterior and median alveolar canals, divide off directly from the infra-orbital canal and are continued as grooves within the wall of the antrum of Highmore. They transmit the corresponding nerves and blood- and lymph-vessels to the premolar, canine, and incisor teeth. The posterior alveolar canals, of which there are two or more, are continued from foramina on the infratemporal surface of the maxillary bone. They transmit the alveolar nerves and vessels to the molar teeth and also to the wails of the antrum. Within the wall of the maxillary bone all these canals form grooves rather than canals. Very little is known yet of the lymph-vessels of the accessory sinuses. Schweitzer’ states he observed that lymph-vessels from the maxillary sinus passed out of the infra- orbital foramen and entered the submaxillary lymph-glands. In the endless controversies concerning the identity or differ- ence of tissue spaces and true lymph spaces it has been customary to use the investigations of the cornea of the eye as the chief basis for discussions. The corneal spaces are not recognized now as lymph spaces. These and other spaces, like Tenon’s space, the suprachoroidal space, spaces in joints and tendons, the endo- and perilymphatie spaces of the ear have only a remote rela- tionship to the lymph system; their functions differ in every case; frequently they serve only to facilitate gliding motions and dis- placements necessary in the movements of the eye. The iris contains spaces filled with fluid, which communicate with the anterior chamber and with the spaces in the ligamentum pectinatum through the furrows or crypts on the anterior sur- face. These spaces in the iris are regarded as belonging to the lymph system. Genuine lymph-vessels have not been demonstrated either in the choroid or the sclera. According to Sattler,!? the veins of the vascular layer of the choroid are surrounded by perivascular 138 KAETHE W. DEWEY sheaths, lined with endothelial cells. Toward the capillary layer, there exists, he believes, a continuous endothelial mem- brane which represents the limiting membrane of the vascular layer. There are no lymph-vessels in the retina. It has become customary to consider the ciliary body as the main source of the intra-ocular fluid (Leber,!’ Wessely!*: 2°). Hamburger: ascribes also to the iris an important réle in the function; in fact, he believes that every part of the eye partici- pates in the secretion and resorption of the fluid. Wessely is of the opinion that it comes nearest to a transudate. It does not contain any substance which is foreign to blood-serum. There is, hence, no reason why we should not consider the process of its secretion as a filtration process. Some difficulties arise from the relatively high salt content and the involved greater osmotic pressure, a property which it shares with the lymph. The most striking difference is no doubt the low albumen content which places it, on the one hand, in a class with the cerebrospinal fluid, the amniotic fluid, and the urine excreted in the glomeruli of the kidney, and, on the other hand, makes it stand in marked contrast to the lymph. Counterpressure to transudation may be the explanation; but we are quite as well justified in supposing that the presence of a special epithelial layer which covers the vessels may be the cause of the retention of the albumen. In the eye, the epithelium of the ciliary processes and the endothelium of the iris may act as such barriers. Schnaudigl" expresses the view that the vitally staining granu- lar cells in the connective tissue of the ciliary body may be the chief agents in the secretion of the intra-ocular fluid. The epi- thelial cells covering the ciliary processes remain colorless in in- jections of trypan blue, an observation which I also made with lithium carmine. It does not seem permissible to me to assume this specific function from the mere fact that these cells have a pronounced affinity for stains. For we must bear in mind that not only do vitally staining cells practically occur throughout the body in the connective tissue, but also that invariably they are larger and more coarsely granular in definite regions of the body, for example, in the pia of the brain, where they occur in patches, LYMPHATIC SYSTEM OF THE EYE 139 in the choroid plexus, in certain regions of the nasal apparatus. On the other hand, there are cells admittedly endowed with secretory functions, cells other than those within the connective tissue, which also have a pronounced affinity for vital stains (the epithelial cells of the choroid plexus, in the hypophysis, the thyroid gland, the syncytial cells of the placenta, the epithelial cells of the convoluted tubules of the kidney), while other cells of a similar type are not stained by trypan blue or carmine. I am more inclined to believe that, inasmuch as these particular vitally staining cells occur practically everywhere in the con- nective tissue, they have everywhere the same function to per- form and, inasmuch as in some localities they are invariably more intensely stained, they are involved either more intensely in the same process or in another associated function. Along this line of reasoning we may also assume that the function of lymph secretion or lymph resorption is associated with the secretion of a fluid related to lymph, such as the cerebrospinal fluid, the in- tra-ocular fluid, or even the chyle. From this standpoint the great scarcity and smaller size of vitally staining cells in the iris would speak against the view of some writers that the iris is notably involved in the secretion of the aqueous humor, while the presence of a large number of intensely staining granular cells in the ciliary body support the more generally accepted theory that these are the main source of the intra-ocular fluid. On the other hand, there is nothing in my view of the part which the vitally staining cells play in the lymphatic apparatus that would contradict the view expressed by Hamburger that there is a more active resorption of the fluid by the iris through lymph- channels than the generally assumed venous drainage into the canal of Schlemm. The fluid has a direct entrance into the iris through the crypts and thence into the lymph-vessels. Ac- cording to my observation, lymph-channels which simply con- vey lymph have no vitally staining endothelial cells. This might explain the curious fact that there are so few of such cells in the iris, especially in the anterior portion. As to the drainage into the canal of Schlemm, Hamburger states, that the resorption through the spaces of Fontana may also be along perivascular lymph-spaces and not by the blood-vessels. 140 KAETHE W. DEWEY to ou 16 BIBLIOGRAPHY Dewey, Kaerue, ANp Noyes, F. B. 1917 A study of the lymphatic vessels of the dental pulp. Dental Cosmos, vol. 58, p. 436. Noyes, F. B., ann Dewey, Karrue 1918 The lymphatics of the dental region. Journ. Am. Med. Ass., vol. 71, p. 1179. Barres, P. 1909 Das Lymphgefiisssystem. S. 50. Jena. Bircu-Hirscuretp, A. 1909 Die Krankheiten der Orbita. Graefe-Sae- misch Handbuch der gesamten Augenheilkunde, 167-170 Lieferung. S. 261. Grenert, K. 1903 Die Augensymptome bei Vergiftung mit Paraphenylen- diamin nebst Bemerkungen iiber die Histologie der Triinendriise. Ber. iiber d. 31, Vers. d. Ophth. Gesells., S. 208. Marsumoro, H. 1901 Ueber die Giftwirkung des Paraphenylendiamins. Wirzburg, I. D. Puree, G. 1896 Ueber Paraphenylendiamin Vergiftung. Vierteljahrs- sehr. f. gerichtl. Med., 3. Folge, Bd. 12, Supplementsheft, S. 116 (quoted by Matsumoto). Dewey, Karrue 1918 A contribution to the study of the pathways of the cerebrospinal fluid and the choroid plexus. Anat. Ree., vol. 15, p. 1. Kunket, A. J. 1901 Handbuch der Toxikologie, 8. 616. Jena. Detamere, G. 1904 The Lymphaties; Chicago, 71 (translated from Poirier and Charpey by Leaf). Renaut 1907 Les cellules connectices rhagiocrines. Arch. d’anat. micro- scop., vol. 9, p. 495. Evans, H. M. 1915 The macrophages of mammals. Am. Journ. of Phys., vol. 37, p. 242. Scunavupier, O. 1913 Die vitale Firbung mit Trypanblau am Auge. Arch. f. Ophthalm., vol. 86, p. 93. GotpMANN, E1909, 1912. Die fiussere und innere Sekretion des gesunden und kranken Organismus im Lichte vitaler Farbung. Beitr. z. klin. Chir., Bd. 54, S. 192, and Bd. 78, S. 1. Most, A. 1905 Ueber die Lymphgefiisse und die regioniiren Lymphdriisen der Bindehaut und der Lider des Auges. Arch. f. Anat. u. Physiol., Anatomical part, p. 96. Scuwerrzer, G. 1907, 1909 Ueber die Lymphgefiisse des Zahnfleisches und der Zihne beim Menschen und bei Siiugetieren. Arch. f. mikrosk. Anat. u. Entwickl., Bd. 69, S. 807; ibid., Bd. 74, S. 927. Quoted by Koetiiker, A. 1902. Handbuch der Gewebelehre des Menschen, Gefiisssystem. Bd. 3, 8. 665. Leipzig. Leper, T. 1913 Die Cirkulations- und Ernihrungsverhiltnisse des Auges. Graefe-Saemisch Handbuch der ges. Augenheilk., Bd. 2, 2. Aufl. Wessexy, K. 1905 Der Fliissigkeits- und Stoffwechsel des Auges mit be- sonderer Beriicksichtigung seiner Beziehungen zu allgemein physiolo- gischen und biologischen Fragen. Erg. d. Phys., Wiesb., Bd. 4, 8. 565. 1908 Experimentelle Untersuchungen tiber den Augendruck, sowie iiber qualitative und quantitative Beeinflussung des intraokularen Flissigkeitswechsels. Arch. f. Augenheilk., Bd. 60, S. 97. Hameurcer, C. 1914 Ueber die Ernihrung des Auges. Leipzig. PLATE 1 EXPLANATION OF FIGURES 1 Retrobulbar muscle tissue, stained with hematoxylin. a, blood-capillary winding about a muscle fiber; b, vitally stained granular endothelial cell, pre- sumably of the lining of a lymph-vessel with collapsed walls; c, blood-capillary with two nuclei and separated blood-corpuscles, illustrating how the walls col- lapse as those of the lymph-capillaries, when no corpuscular elements hold them apart. 2 Cross-section through the ciliary body, selera, andconjunctiva. Unstained. a, large granular endothelial cells in the ciliary processes;b, smaller cells at the base of the processes; c, fewer slender cells in the outer third of the sclera. There are none in the inner two-thirds of the scleral tissue; d, numerous larger cells in the conjunctiva. 3 Longitudinal section of a ciliary process. Stained lightly with hema- toxylin. a, epithelial cells; b, blood-vessels; c, large granula cells. 142 . LYMPHATIC SYSTEM OF THE EYE PLATE 1 KAETHE W. DEWEY Resumen por el autor, Ralph A. Kordenat, Universidad de Illinois. Contaminaci6n de los cadsveres por el Saccharomyces cerevisiae. El crecimiento de hongos sobre los cadsveres es causa de con- siderable pérdida de material en los laboratorios anat6micos. El presente trabajo da a conocer la existencia de tal contami- nacion. Un estudio de los caracteres de los cultivos de dichos hongos, sus propiedades de coloraci6én, morfologia y experimentos sobre animales, demuestran que esta “levadura”’ es una variedad no patégena y saprofitica del Saccharomyces cerevisiae. Un estudio de varios germicidas y antisépticos demostré que el cre- cimiento de estos hongos se impide embalsamando los cadiveres con la siguiente formula: Glicerina, 300 ce.; formol, 400 ec.; al- cohol, 1000 ce.; fenol, 90 gramos; agua, 400 ce. Primero se usé el bicloruro de mercurio (90 gramos), pero después se omitié su empleo porque forma un coigulo resistente y granular en los vasos sanguineos, que impide la penetracién completa del liquido embalsamador, y, ademis, por el coste de dicha substancia qui- mica. Su presencia en el caddver no es necesaria para impedir el crecimiento del hongo. Como medida profilictica pafios mojados en la siguiente solucién, con los que se envuelven los cuerpos, im- piden el crecimiento de la levadura asf como la desecacién y endurecimiento rapidos de los mtisculos expuestos. La soluci6én se compone de: Glicerina, 50 cc.; fenol, 2 gramos; alcohol, 50 ee.; agua (que se afadird) 1000 ee. Translation by José F. Nonidez Cornell University Medical College, N. Y. ———— AUTHOR'S ABSTRACT OF THIS PAPER ISSUED BY THE BIBLIOGRAPHIC SERVICE, MAY 24 CONTAMINATION OF CADAVERS BY SACCHAROMYCES CEREVISIAE RALPH A. KORDENAT Departments of Bacteriology and Anatomy, University of Illinois College of Medicine, Chicago, Illinois TWO FIGURES Recently the cadavers in the anatomical laboratories of the University of Illinois, College of Medicine, became covered by a moist, slimy, slightly elevated growth that has caused no small amount of trouble and annoyance. The growth is dirty gray in color, loosely adherent, and does not penetrate the deeper tis- sues. It has never been noticed upon the unbroken skin of the cadaver; when the skin is removed, however, the growth begins and spreads with great rapidity, making dissection of the speci- men out of the question and causing great waste of material. A quantity of this grayish substance was taken to the bacteri- ological laboratory for examination. Smears showed a large number of highly refractive, ovoid cells, measuring about 7u in diameter. In addition to these, there were large numbers of bacteria, especially staphylococci. It seemed plain that the slimy growth was largely made up of the above-mentioned ovoid cells, and cultures were therefore made in order to isolate and study them in detail. After several attempts, pure cultures of the organism in ques- tion were obtained. CULTURAL CHARACTERISTICS Neutral plain agar. After twenty-four hours’ incubation at 37°C. small, round, bluish-gray colonies, about the size of a pin- head were seen. Their margins were smooth and regular. After an additional twenty-four hours’ incubation at room temperature 145 146 RALPH A. KORDENAT these colonies turned white in color, but did not increase in size or number. Five per cent dextrose agar. Twenty-four-hour culures showed a growth similar to that on plain agar. After another twenty- four hours at room temperature they were much larger and creamy white in color, becoming confluent in most cases so as to cover the entire surface of the media. The characteristic odor of ‘yeast’ was noticed. Plain broth. The growth in plain broth was not profuse. There was a slight flocculent sediment at the end of twenty-four hours. The broth was slightly turbid. Five per cent dextrose broth. The growth was similar to that in plain broth, but more pronounced; a heavy sediment and the characteristic odor of yeast. Litmus milk. A marked acid production at the end of forty- eight hours with coagulation; the curd in most cases being com- pletely digested, leaving a whitish turbid whey. Gelatin stabs. Gelatin-stab cultures showed only a slight growth upon the surface, resembling that on plain agar. No liquefaction. The organism ferments glucose with the formation of carbon dioxide and alcohol. STAINING PROPERTIES The organism stains fairly well with the ordinary dyes and exceptionally well by the Gram method, being strongly Gram- positive (figs. 1 and 2). When stained by Wright’s stain, a well- defined blue cell membrane is seen with pale blue mitochondria and numerous vacuoles within. MORPHOLOGY The organisms average about 7 » in diameter and are round to ovoid in form. In a hanging-drop preparation of a forty-eight- hour culture, a highly refractive, non-motile, double-contoured cell is seen in an active state of budding. The budding gener- ally takes place from the long end of the ovoid cells. The younger CONTAMINATION OF CADAVERS 147 cells are small and more rounded in form, while the older cells, from which the budding takes place, are more elongated. There is no tendency to form mycelia. A pure known culture of Saccharomyces cerevisiae was com- pared with the organism taken from the cadaver, and it was found that in every way the two resembled each other in morphology, staining properties, and in general cultural characteristics. ! =i Fig. 1 Strain ‘A.’ Saccharomyces cerevisiae from cadaver. Gram’s stain (1200). Fig. 2 Strain “B.’ Known pure culture of Saccharomyces cerevisiae. Gram’s stain (1200). ANIMAL EXPERIMENTS White mice, after being inoculated with rather large doses of a normal salt suspension of the organism, showed no ill effects. An effort was made to reproduce the growth upon animals. Two dead rabbits, with the skin and viscera removed, were im- mersed in the embalming fluid used for the preparation of the bodies in the anatomical laboratories. This embalming fluid consists of— 148 RALPH A. KORDENAT Gi yaerite «i. Warmzeee se aa'ce cece Push sic cola ohn eee ae ae 300 ce. Formalin oiiin nite reds avs pawn cp akticlts what ac eee een 400 cc. Alonhol. sce ences Kees cue Taine a we tonae Ook eee ae 1000 ce. Phenol... a.tivic ch sas coat chee otic ess t imnee aetna ec a 45 grams Writer’ x ciaec are sed } vitae Pant ation ss.0-odroke wren) lath one tor a ate 400 ce. After a period of one week they were removed and a pure culture of the cadaver organism planted upon one and a pure known cul- ture of Saccharomyces cerevisiae planted upon the other. At the end of three days the entire bodies of the two rabbits were similarly covered with a slimy, grayish film. Two days later this growth became a dirty, creamy white and resembled that found upon the cadavers. Thus, it is further evident that the two organisms are alike. THERMAL DEATH POINT A series of small test-tubes, each containing 2 cc. of a suspension of the cadaver culture (strain ‘A’) and a known strain of Sac- charomyces cerevisiae (strain ‘B’) were used. At the different degrees of temperature indicated in the table, tubes of each of the two organisms were placed in a water-bath for a period of ten minutes, allowing one minute for the temperature of the tubes to reach that of the water-bath. The tubes were then removed and 5 per cent dextrose-agar slants inoculated and incubated. ‘The results are given in the table. Both organisms were killed at 58°C. for ten minutes, but not at 56°C. for ten minutes. Because of the apparent identity of the cultural characteris- tics and staining properties, as well as the results of the animal experiments with the organisms, it is further evident that the contamination of the cadavers is a strain of Saccharomyces cerevisiae. I have been able to find nothing in the literature concerning the contamination of cadavers by Saccharomyces cerevisiae. In a personal communication from Dr. Irving Hardesty, of Tu- lane University, he states that he has had a similar experience with ‘molds,’ that the mold thrives on formalin-hardened bodies, that aleohol favors its growth, and that carbolie acid will not check it unless the bodies are completely immersed in the car- bolic solution. CONTAMINATION OF CADAVERS 149 In order to find some disinfectant for this organism that might be effective in embalming fluids, the following experiments were performed: The carbolic coefficients for potassium chromate, formalin, and mercuric bichloride were determined according to the method advocated by the U. 8. P. H. 8. (Hygienic Laboratory Bulletin no. 82) and further described by M. J. Rosenau in his test on “Preventive Medicine and Hygiene.” Instead, however, of find- ing the coefficient with the use of a twenty-four hour culture of typhoid bacillus, forty-eight hour cultures of the two strains of TABLE 1 Thermal death point TEMPERATURE (10-MINUTE EXPOSURE) STRAIN ‘A’ GROWTH STRAIN ‘B’ GROWTH op 48 Positive Positive 50 Positive Positive 52 Positive Positive 56 Positive Positive 58 Negative Negative 62 Negative Negative 64 Negative Negative 68 Negative Negative 70 Negative Negative 72 Negative Negative 74 Negative Negative 78 Negative Negative Saccharomyces cerevisiae were used, because the yeast is in its most active state of budding at that time. It was found, by determining the carbolic coefficient, that phenol is the most efficient disinfectant for these yeasts. The action of mercuric bichloride toward these organisms is too inconstant for one to reach any definite conclusion as to its use. Formalin and potas- sium chromate have too low a coefficient to be of any value. The prevention of this growth was now attempted by altering the composition of the embalming fluid previously used. A rab- bit was embalmed with the following fluid: THE ANATOMICAL RECORD, VOL. 19, NO. 2 150 RALPH A, KORDENAT Kol yoorint. srastares sca sinuke Neds Gaels dak Sct aly oi iabo ONE UEN. POG hie 300 ce. POROUS Re cccce os ssh nenthicy Glote Sv Sale uelimusiee eager 400 ce. BIGONGU scx teieree ciov < ew cela sis 6 8i5i0.010)> 8 Vip sel baie Vides aii Gee 1000 ce. WNGNGL ager wie o'e cd ve oven mob 86m nve.s asses eiate/e Repeater Ao 90 grams Morouricibiohloxide: 9 (1c. 6h 2558. kk cess beaelcek eeee 90 grams WY BOD jo otealy eva = tebe tee iots sks ara sa atau ete aie eee 400 ce. It will be seen that this solution differs from the one previously mentioned in that the phenol is doubled and mercuric bichloride is added. The rabbit was immersed in the same solution for three days, seeded with cultures of both yeasts, and then covered with moist towels. At the end of four days there was no growth. It was considered inadvisable to include mercuric bichloride in the embalming fluid not only because of the extra expense, but because there is a granular coagulation of the blood in the small vessels. This firm, granular coagulum completely obstructs the smaller vessels, thus preventing the thorough penetration of the. solution. Other rabbits, embalmed with the same fluid minus the mercuric bichloride, were seeded with both strains of the yeast and incubated for four days. These also showed no growth. An examination was made of the dust taken from the floor, walls, and tables of the anatomical laboratory. Some of this dust was taken up by means of a sterile cotton swab and 5 per cent dextrose broth and agar inoculated and then incubated for twenty-four hours at room temperature. Many of the sam- ples revealed Saccharomyces cerevisiae. As a prophylactic measure, cloth was soaked with the following solution: GU ORTIN oa, ind. = Wades bash ohea eyes ies «Sew ees See 50 ce BSOMIN 10.3 arcs necle < vo bicehin <2 Wuke Man nivale cues tne ane ae 2 grams PUIGODION S «0's: 'k.2:4:ctop saree ah hare Ne epiela a ate a staid eRe aetele ae iN Rets 50 ce Water (a: 8. 8). aa demeknae th eee eal o's se Cue es eee 1000 cc. and was draped over one-half of the bodies in the laboratory (group A) at the end of each dissection for a period of four months. The other half of the cadavers (group B) served as a control. During these four months none of the bodies of group A was affected, while six of the bodies of group B became covered with the growth. ee ee CONTAMINATION OF CADAVERS 151 By applying the above solution upon the embalmed bodies, the specimens are not only protected from the yeast but the glycerin keeps the exposed muscles more soft and pliable. CONCLUSIONS Because of the apparent identity of the cultural characteris- ties, morphology, staining properties, and of the animal experi- ments mentioned, it is concluded that the organism in question is a saprophytic strain of Saccharomyces cerevisiae. The growth of Saccharomyces cerevisiae upon anatomical spe- cimens renders them useless, thereby causing great waste of material. Phenol is the most efficient disinfectant for this particular strain of yeast. The contamination can be prevented by using the embalming fluids and the prophylactic measures mentioned. The use of mercuric bichloride in embalming fluids is not prac- tical; first, because it forms a firm granular coagulum of blood in the vessels, thus preventing the complete penetration of the fluid, and, second, because of the expense of the chemical. The pro- phylactic measures indicated not only protect the cadavers from the Saccharomyces cerevisiae, but prevent rapid drying and hardening of the exposed muscles. dd) (2.200 Te ROR ERIATING ud > pi ; wiy . ' " F le f tipo qty ail 4 a i] { % 7 P ‘5 im" Pai fy é “ 1 i hy tii) wegen Uh] ih § Oe fo sl bF- i TLC <_ re a ti “9 ap * ‘ Abstracted by E. D. Congdon, author. Leland Stanford Junior University. Simultaneous occurrence of very small sphenoid and frontal sinuses. Because of the uncertainty as to the reason for failure or in- completeness of sinus development, the present almost unique instance of very rudimentary condition of four sinuses merits description. The sphenoid sinuses were symmetrical in form and position. They were about 4 mm. in sagittal and 14 mm. in craniocaudal diameter. A lateral extension of the cavity brought each into series with the corresponding posterior ethmoid cells. The ostium of the left sinus was so far forward and so lateral as to almost justify the interpretation that it was an ethmoid cell. The ostium region on the other side was destroyed. The cavity interpreted as the left frontal sinus was so small that it is not certain that it extended beyond the ethmoid bone. There was no especial condensation of compact bone to warrant the supposition that, the sinuses may have been hindered in their development by infantile disease. It is possible that the sphe- noid sinuses are to be grouped with others previously described by the writer which were apparently unable to expand through material of the concha-presphenoid fusion plane. No compensa- tion for the loss of these cavities was noticeable in the size of the other sinuses. AUTHOR'S ABSTRACT OF THIS PAPER ISSUED BY THE BIBLIOGRAPHIC SERVICE, JUNE 21 SIMULTANEOUS OCCURRENCE OF VERY SMALL SPHENOID AND FRONTAL SINUSES E. D. CONGDON TWO FIGURES A few very small sphenoid sinuses have been recorded, and com- plete absence has been claimed by several observers. Incomplete development and absence of frontal sinuses are both rather fre- quent. Only one previous record was found of the slight devel- opment of sinuses of two types in the same individual. This also had to do with the frontal and sphenoid cavities. They were described by Wertheim (’01) in an eight-year-old child. The observation was made for a sufficiently early stage of de- velopment to admit of the possibility that the deficiency would have been made good to a considerable degree before adult life. The explanations which have been advanced for the absence and incomplete development of the sinuses are at present sup- ported by little evidence. Information regarding the paranasal region needs to be collected in these cases if any explanation is to become more than a hypothesis. Although it is especially desirable that this be obtained for foetal and infantile specimens, since observations on such material will of necessity be rather infrequent, the conditions surrounding absence or incomplete development of adult sinuses should be examined for what- ever information it can afford. The rudimentary sinuses were found in the course of dissection and were preserved with the mucoperiosteum nearly intact. The subject was an adult male apparently of European parentage. The small spherical cavities were symmetrically developed and extended to the orbit behind the last posterior ethmoid cell (fig. 1). The anteroposterior diameter of the portion lying within the area usually ascribed to the sphenoid was 4 mm. and its height 14 mm. upon the right and 12 mm. upon the left side. 153 154 E. D. CONGDON The ostium of the left sinus opened backward, although it was so far lateral as to be little posterior to the nearest ethmoid cell. Were it not for the position of the aperture, the sinus could as well be classified as a posterior ethmoid cell with a recess in the sphenoid bone, because the part of the cavity in series with the ethmoid cells has a position frequently occupied by one of them, and the most posterior ethmoid cell also not rarely invades the supero-anterior part of the sphenoid where the median portions of these sinuses were located. Fig. 1 Parasagittal diagrammatic drawing through left sphenoid sinus (a). Three posterior ethmoid cells as (b) represented by dash lines. A fourth, the most posterior which had been opened in dissection outlined in an unbroken line. Above it the aperture of the sphenoid sinus also shown by an unbroken line. x4. The portion of the wall of the right sphenoid sinus corre- sponding to the aperture of the left is not perforated and no com- munication of the sinus on this side with the nasal cavity occurs elsewhere. A saw cut has destroyed that part of the wall lying a little more medially. Either the aperture must have been situated in this region then or the sinus lacked an outlet. There has been considerable discussion as to whether this second al- ternative ever occurs. Some authors categorically deny that a sinus can originate without an opening, since they believe sinus formation is always by the out-pocketing of the nasal cavity. Zuckerkandl (’93) stafes that he has seen two sphenoid sinuses — 7 lil aes EO VERY SMALL SPHENOID AND FRONTAL SINUSES 155 without apertures in their bony walls. No other record of the lack of opening to the osseous wall of a sphenoid sinus was found. Evidentlyits absence is very rare, although closure of the aperture by the swelling of the mucosa is frequent. For this reason and because the closely similar companion sinus had an opening, it is very probable that its aperture was destroyed by the saw. 9 Fig. 2 Right frontal sinus (a). X 1. The more rudimentary of the two frontal sinuses is shown in figure 2. There is a marked difference in the frequencies of absence of the frontal sinus as given by various authors. Onodi C11) places it as high as 20 per cent, while Boege (’02) finds it to be only 4.9 per cent. Much of this discrepancy is probably due to different conceptions of what constitutes the earliest developmental stage of a frontal sinus as contrasted with a be- ginning ethmoid cell. The recess (fig. 2, a) is here regarded as a frontal sinus because it is already separated by a ridge from another division of the frontal recess and is in the proper position 156 E. D. CONGDON to enlarge directly into the frontal bone. It is the passage into the frontal bone upon which the application of the term frontal to a sinus should depend, but it is usually not practicable, even if it is not impossible, to determine whether small out-pocketings of the frontal recess have passed beyond the confines of the eth- moid bone or not. No peculiarities were observed in the other paranasal sinuses whieh could aid in finding the reason for the rudimentary condi- tion of the frontal and sphenoid sinuses. The spongy bone sur- rounding the four sinuses was somewhat more dense than the average. It may be, therefore, that foetal or infantile disease may have brought about a condition which interfered with the enlargement of the sinuses. Onodi (11) and Wertheim (’01) have brought together some evidence of such an occurrence. ‘The condensation of the spongy bone was not extreme, and, since there was no atrophy of the mucosa, the argument for early dis- “ase is not convincing. Furthermore, it would be surprising that sinuses at opposite ends of the nasal cavity should be af- fected while the maxillary and ethmoid sinuses opening at inter- mediate positions are normally developed. The explanation first suggested by Toldt (83) for the origin of the bony plates in the sphenoid sinus and further elaborated by Cope (17) and the writer (119) may possibly be applicable also to the retardation of the sphenoid sinuses. ‘Toldt regarded the planes and ridges as the remnant of material at the plane of fusion of the adjacent ossification centers of the sphenoid sinus which was able to resist the absorptive action of the periosteum during the enlargement of the sinus. Seven sphenoid sinuses out of two hundred and forty-two were found by the writer (719) whose posterior walls corresponded in position and direction with the usual plane of fusion of conchal and presphenoid centers. This led to the suggestion that resis- tant material had prevented the extension of the sinus backward The two rudimentary sinuses here under discussion have pos- terior walls lying more anteriorly and somewhat more trans- versely than the usual position of the plane. It may be that in this instance a plane situated especially far anteriorly put an early stop to the backward extension of the sinuses. VERY SMALL SPHENOID AND FRONTAL SINUSES 157 The incomplete development of the two pairs of sinuses in the same individual is suggestive of a correlation between the development of the two types. The interrelation of form and size of adult sinuses seems to show that alternative correlation is a common feature of sinus development when one of two adjacent sinuses succeeds in preempting space originally open to both and thus brings about the underdevelopment of its neighbor. The suggestion has also been made that as an adaptation to keep the total sinus space up to the usual amount the underdevel- opment of some sinuses might be correlated with an unusually extensive growth of others through some unknown mechanism. As far as could be found, there is no evidence for the occur- rence of a growth response of this nature. If there is a correla- tion which explains the concurrent retardation of development of the four sinuses in the specimen which has been described, it differs in type from the relationship just referred to in that the sinuses all vary from the norm in the same direction. The retardation or absence of two frontal sinuses is so often bilateral as to be probably correlated. Less data are at hand for sphenoid sinuses, though a certain degree of correlation is probable. The retardation of development of frontal and sphenoid sinuses in the same head is so rare that its coexistence in the two types is probably a matter of chance. LITERATURE CITED Boece, K. 1902 Zur Anatomie der Stirnhéhlen. Inaug. Diss., K6nigsberg. Conepon, E.D. 1919 The distribution and significance of septa in the sphenoid sinus. Corr, V.Z. 1917 The internal structure of the sphenoid sinus. Jour. of Anat., vol. 51. Cryer, M. H. 1916 The internal anatomy of the face. Philadelphia and New York. Onopr, A. 1911 Die Nebenhéhlen der Nase beim Kinde. Wiirzburg. Toutpt, C. 1883 Osteologische Mittheilungen. Ztsch. f. Heilkunde, Bd. 4. WerTHEIM, E. 1901 Beitrige zur Pathologie und Klinik der Erkrankungen der Nasen nebenhéhlen. Arch. f. Laryngol., Bd. 11. ZUCKERKANDL, E, 1893 Normale und pathologische Anatomie der Nasenhéhle und ihrer pneumatischen Anhinge. Bd. 1, Zweite Aufl., Wien und Leipzig. Abstracted by E. D. Congdon, author. Leland Stanford Junior University. Anomalous fibrous cords in the hand and the phylogeny of the flexor digitorum sublimis tendon. The fibrous cords are evidently remnants of the ancestral short flexor muscles of the hand which are normally represented by the distal part of the flexor digitorum sublimis tendons, accord- ing to Eisler’s theory. They were attached proximally on the radial sides of the bases of the proximal phalanges of the fourth and fifth digits and extended distally to bifurcate like the flexor digitorum sublimis tendons and insert on either side of the volar surface of the middle phalanx. The coexistence of the cores with normal flexor digitorum sublimis tendons apparently either contradicts this interpretation or disproves the theory. Also Bardeleben and Kajava state that the flexor digitorum sublimis tendon may exist side by side with the short musculature in cer- tain mammals, and Fromont describes an anomaly in the human hand showing this condition. Since there are compelling rea- sons both from comparative anatomy and embryology for Eisler’s theory, it is probable that in these apparently contradictory instances the rudiments of the short flexors split to go only in part to the sublimis tendon, while the rest was retained to form more or less perfect short superficial flexor muscles. AUTHOR'S ABSTRACT OF THIS PAPER ISSUED BY THE BIBLIOGRAPHIC SERVICE, JUNE 21 ANOMALOUS FIBROUS CORDS IN THE HAND AND THE PHYLOGENY OF THE FLEXOR DIGITORUM SUBLIMIS TENDON E. D. CONGDON TWO FIGURES Tendon-like cords were found in one hand of an aged male subject during the course of dissection by Mr. A. F. Warren. They lie upon the volar sides of the fourth and fifth fingers of. the right hand and are closely similar in form and position (fig. 1). Each extends distally from an attachment on the radial side of the base of the proximal phalanx to the volar surface of the vaginal ligaments and there bifureates. Theslips thus formed pass to the opposite sides of the middle phalanx to insert into the vaginal ligament the adjacent fascia and the border of the dorsal extensor aponeurosis. Although of a somewhat less compact structure than a tendon, they can by no means be described as mere condensations of fascia. They did not bring about any marked flexion of the digits in the cadaver, and probably did not hamper movement during life. The muscles to which the cords seem related are the short superficial digital flexors of amphibia, reptiles, and mammals. These take origin usually upon or in the volar fascia and have insertion in part at least by a pair of slips upon the sides of the metacarpo-phalangeal joint or more distally. The cords differ from the muscles in the position of their proximal ends. In- stead of passing to the palmar aponeurosis along the mid-line of the digit they are deflected to the side of the base of the proxi- mal phalanx. The dissimilarity is not great, however, because the cords are in continuity on the phalangeal bases with slips of insertion of the palmar aponeurosis. The relationship of the cords are not like those of the lumbricales or interossei, nor are either of these muscles abnormal or lacking. 159 160 E. D. CONGDON The presence of ten short digital flexors in urodele amphibians, in monotremes, and marsupials is generally accepted as sufficient reason for regarding the structures as an ancestral muscle for man and other mammals possessing the flexor digitorum sub- limis muscle. As will be seen Testut and Fromont have also described the primitive short superficial flexors in the adult human hand. It can be accepted with a large degree of con- fidence then that the anomalies in question are actual short superficial flexor remnants. Fig. 1 Hand (after Fromont, with parts omitted) showing abnormal digital muscles. a.a, tendon of flexor digitorum sublimis upon which are inserted muscles (c.c), interpreted here as short superficial digital flexors; b.b, muscles interpreted as short superficial digital flexors taking the place of tendons of flexor digitorum sublimis. X }. The flexor digitorum sublimis muscles of man and many mam- mals said to arise in part from the short superficial flexor muscles lie in large part within the fore arm, but send their tendons through the palm to the digits. Here they bifurcate to insert on either side of the second phalanx. The flexor digitorum pro- fundus, a companion muscle, whose muscle belly is also in the arm, inserts on the distal phalanges by tendons which pass be- tween the bifurcations of the sublimis insertion. Eisler (’95) suggested that the terminal portion of the sublimis tendon with its bifurcated insertion might be nothing else than a degnerated superficial flexor muscle which after having changed completely to tendon had come, by means of its attachment to the palmar ANOMALOUS FIBROUS CORDS IN HAND 161 aponeurosis, to be continuous with a part of the fore arm flexor mass which earlier inserted on the palmar aponeurosis. MeMurrich’s careful study of the flexor muscles of amphi- bians, reptiles, and mammals (’03) gave confirmation and ampli- fication to Hisler’s suggestion. It received support of another kind when Grifenberg (’05) found that a short flexor muscula- ture in the hand of the human embryo connected with a fore arm mass to form a flexor sublimis. With this view of the origin of the flexor digitorum sublimis muscle it is not to be expected that any mammalian finger will possess at the same time one of its tendons and a short super- ficial flexor muscle. Kajava (11) who has examined the digital flexor musculature of monotremes and eleven species of marsupials found, as did MeMurrich for other animals, that the two never occurred together in the same digit. Yet Kajava states that there are certain insectivora and carnivora which do possess both the flexor superficialis brevis and the sublimis; Bardeleben (90) much earlier made a like claim for Hyrax and, according to Hisler (95), for Paradoxurus. References by two authors to aberrant muscles of the human hand related to the anomaly here described bring confirmation to the theory of end-to-end fusion for the sublimis, but at the same time in part offer difficulties similar to those found by Kajava and Bardeleben. Testut is quoted by Kajava from a work which was not accessible as giving instances of the oecur- rence of a short flexor in the human hand for the little finger which had replaced the corresponding sublimis tendon. Fromont found a similar displacement of the flexor sublimis in two digits of the hand. His figure is copied here (fig. 2b). A better confirmation of the theory of end-to-end fusion by a reappearance of the primitive structures could scarcely be de- sired. The condition of the musculature of two other digits were found however to be more involved, the flexor sublimis was present in each of them, but there were also other slender muscle bellies taking origin from the transverse carpal ligament. and inserting on the sublimis tendons (fig. 2a). The conclusion seems necessary that in these two digits part of the embryonic 162 E. D. CONGDON rudiment derived from the ancestral short flexor have given rise to the corresponding muscles in the adult. The relationships and origin of these slender muscles are also like those of the two larger short superficial flexors. Fromont terms the two of the four short muscles which insert on the sublimis tendons super- ficial lumbriecals, but likelihood of identity with lumbricals is excluded by their relationships and by the presence of almost normal lumbricals in the usual position in the digits to which they are related. Fig.2 Fourth and fifth digits of left hand with tendinous cords \a.a’) apparently representing remnants of short superficial digital flexors. X }. It has been seen that the instances of abnormal human muscular development described by Testut, Fromont, and the writer con- firm the comparative anatomical evidence taken from a wide field by Eisler, MeMurrich, and Kajava for the theory of end-to- end fusion to the extent that they reveal a tendency toward the formation of short superficial digital flexors in man. But at the same time the anomalies of Fromont and the writer present a difficulty for the theory in the simultaneous occurrence of the short superficial flexors and the tendons which are supposed to arise from them, Observations of a like condition in the ANOMALOUS FIBROUS CORDS IN HAND 163 normal structure of a few other mammals have already been referred to. A possible explanation of this contradiction is that when muscle and tendon appear together, the short flexor rudi- ment divided at an early developmental period to give rise to both the muscle and the tendon. The supposition that there were paired short superficial flexors in the human ancestry as in some other mammals and that their rudiments give origin one to the muscle and one to the tendon is not probable because of the rarity of the anomaly. BIBLIOGRAPHY BarDELEBEN, Karu vy. 1890 Uber die Hand- und Fuss-Muskeln der Siiuge- tiere, besonders die des Praepollex (Praehallux) und Postminimus. Anat. Anz., Bd. 5. Fisuer, P. 1895 Die Flexores digitorum. Verhand. Anat. Gesell., Anat. Anz., Bd. 10. Fromont 1895 Anomalies musculaires multiples de la main. Absence du fléchisseur propre du pouce. Absence des muscles de l’eminence thénar. Lombricaux supplémentaires. Bulletins de la Société anatomique de Paris, 5™° Série, T. 9. GRAFENBERG, EF. 1905 Die Entwickelung der Knochen, Muskeln und Nerven der Hand und der fiir die Bewegungen der Hand bestimmten Muskeln des Unterarmes. Anat. Hefte, erste Abt., Bd. 30. Kasava, Y. 1911 Die kurzen Muskeln und die langen Beugemuskeln der Siugetierhand. I. Monotremata und Marsupiala. Vergleichend- anatomische Untersuchungen. Anat. Hefte, erste Abt., Bd. 42. McMourricnx 1903 The phylogeny of the palmar musculature. Am. Jour. Anat., vol. 2. Abstracted by E. D. Congdon, author. Leland Stanford Junior University. Acquired skeletal deformities in a young fowl. A young cockerel reared in an incubator till about three months of age showed marked skeletal deformities which were in part mechanical effects of confinement under a roof with which the bird gradually came in contact as it increased in height. The dorsoventral thoracic diameter was reduced a half. The trunk anterior and posterior to the interacetabular line was bent down- ward. Apparently the down thrust of the neck against the thorax, due to the striking of the head against the roof, together with the downward pull of the leg muscles upon the posterior portion of the trunk in the effort to keep the body from falling forward were responsible for the bend. There was marked under- development and further deformity of the trunk skeleton. The cervical vertebral column approached adult size, but was re- tarded in differentiation. The wattles, comb, and beak showed a differentiation typical of a larger cockerel. The gross appear- ance of the trunk skeleton suggested that the cockerel may have had rickets. No microscopic examination was made. The only indication of poor health which was noted was a ruffling of the plumage for a few days before the animal was killed. ACQUIRED SKELETAL DEFORMITIES IN A YOUNG FOWL E. D. CONGDON Leland Stanford Junior University SIX FIGURES Two young cockerels reared in an incubator showed skeletal deformities approaching in degree the effects of a severe case of human rachitis. Although theinfluence of mechanical conditions upon the form of the mammalian and especially the human osseous system has long been studied, no descriptions were found in the literature of marked deformities in the domestic fowl or any other bird. At the time when it was noticed that the chicks had been kept too long in the incubator, their backs were already in contact with the ceiling. As they grew, their heads must have been gradually forced to a lower level relative to the rest of the body. The cockerels evidenced poor health by a ruffling of their plumage (fig. 1), and they were somewhat sluggish in their move- ments. There is little doubt that the direct mechanical effects due to unusual posture and contact of the head with the roof were complicated by the influence of the other unfavorable con- ditions, such as high temperature and lack of exercise. It may be that the slight thickening at costochondral junctions and at the posterior ends of the uncinates, the bending of certain bones and other disturbances of growth, which will be described, are due in part to rickets and osteomalacia. Insufficient attention was given to the question before the skeleton was cleaned to answer the question. ‘Tripier! tried the effect of diet with low protein content and containing little earth salts upon two young pullets, and described a change in the physical properties of their 1 Arch. de Physiol. norm. et pathol. (2) 1, 1874. 165 166 E. D. CONGDON bones. He did not mention, however, any change in skeletal proportions or in the shape of the individual bones. » The larger and more deformed of the two fowl was used for a detailed examination of the skeleton. Two cockerels were chosen for comparison, one of these showed less maturity than the abnormal bird in comb, wattles, and bill, but was of nearly the same length and height. The other was chosen because the comb, wattles, and bill indicated an equal maturity. It was much larger than the abnormal fowl, though it was of average size in comparison with other normal cockerels in the same stage of development. ‘The controls and deformed bird were all White Leghorn stock of approximately pure breed. Figures 2 to 6 show the abnormal and the smaller control birds under equal magnification. The trunk of the abnormal cockerel is the smaller, although, as will be later seen, it would probably have been as large or larger had it developed normally. Some features of its deformity come out strikingly in the profile view with the trunk musculature in position (figs. 2 and 3). The thoracic region has a dorsal and a ventral diameter about half that of the smaller control. The posterior portion of the trunk is also somewhat smaller. A comparison of figures 2 and 4 shows that incomplete development of the breast muscle and sternal keel play a considerable part in the thoracie reduction, though the body cavity in this region is also disproportionately small in cross-section in comparison with the parts external to the trunk. . The chief skeletal malformation which can be readily traced to a mechanical cause consists of a bending downward of the anterior and posterior portions of the trunk, so that their longi- tudinal axes meet at a slight angle at a transverse plane passing through the hip-joint. The pelvic bones are correspondingly bent at their acetabuli and the sternum at the junction of the cartilaginous and bony portions of the keel. This condition evidently developed as an effect of the frequent down thrust of head and neck upon the thorax, when the head came in contact with the roof as the chicken tried to assume an erect posture. To retain the balance of the body upon the legs at the acetabuli, -] SKELETAL DEFORMITIES IN A YOUNG FOWL 167 Fig. 1 Abnormal cockerel Fig. 2 Abnormal cockere Fig. 3 Younger control cockerel. Magnification the same as in figure 2 Fig. 4 Abnormal cockerel, THE ANATOMICAL RECORD, VOL. 19, No,3 16S E. D. CONGDON when the downward impulse was communicated by the neck to the thorax, the musculature from the legs to the part of the pelvis posterior to the acetubular joints must have contracted with more than ordinary vigor. The two unusually powerful down- ward forces acting at opposite ends of the trunk resulted in the bending at the interacetabular transverse plane. The trunk skeleton shows abnormalities throughout that may not be so directly connected with mechanical influences as is the bending of the trunk. ‘The ribs and uncinates are thicker relative to their length than in the control birds. The ends of the costal and sternal ribs, which articulate with one another, and the posterior ends of the uncinates are enlarged. The dis- proportion of the trunk relative to the neck is shown in the vertebral column by a decrease in size of the successive dorsal vertebrae posterior to the second, in place of the usual increase in their dimensions. The ossa coxae are not only bent, but are narrower than usual in conformity with the diminished diameter of the entire trunk relative to its length. The bend in the body of the sternum has already been mentioned. Its bony keel is of only half the usual dorsoventral extent at its posterior end, and decreases to an inconsiderable ridge anteriorly. The reduction of the keel is probably due in large part to the direct effect of striking the breast against the bottom of the incubator, when as frequently happened, the down thrust of the neck at the thorax caused the animal to topple forward after pushing its head against the roof. It is not probable that underdevelopment of the breast muscle had much, if anything, to do with lack of development of the keel, because other bones associated with these muscles including the coracoid furcula and body of the sternum, if of less than the usual size, are certainly much nearer to the norm than is the keel. The fureula which extends downward from the superior extremity of the coracoid to the antero-inferior angle of the keel has under- gone a reduction in length corresponding to the decrease in the dorsoventral extent of the keel. SKELETAL DEFORMITIES IN A YOUNG FOWL 169 There are details in the form of the skull which may be due to the repeated striking and pressure of the head against the roof. It should be stated, however, that these do not greatly exceed in amount the normal variation as shown in the skulls of four other cockerels of about the same age. The frontal region of the skull seems to have been pushed slightly forward and down (fig. 6). The wedge-shaped projection of the cranial cavity lying between the upper and posterior portions of the orbits is enlarged at their expense, so that the orbital processes of the frontal bone are unusually conspicious in a lateral view of the skull. The anterosuperior orbital region which usually has a nearly straight edge is convex and flares upward, as though the eyeball had been pushed forward against it. A protrusion of the eyeball was not looked for while the animal was alive and it was not noticed. In the photographs of figure 2 and 4 it appears to be present. The comb is bent over as if from frequent contact with the roof, yet its deformity cannot be assigned to this cause with certainty, because lopped combs are not rare among White Leghorns. Other gross malformations of the osseous system not directly traceable to the effects of pressure of the head against the roof manifest themselves both in the form and in the size of the bones. The ribs, uncinates, coracoid, furcula, and cervical vertebrae are thicker and more rounded than in the controls. The pelvic bones and sternum are so irregular in form that they mask any abnormality of a like nature, which may have been present. The surface markings of scapula, coracoid, furcula, sternum, cer- vical vertebrae, ribs, and uncinates are less sharply defined than in the control skeletons. The characteristics of form both as regards general outline and detail consist in a retention of an earlier developmental condition modified perhaps by other path- ological characters. Various parts of the skeleton show irregularities in relative volume, some of which have been already mentioned. Though the retardation of the trunk is so marked that it can scarcely be questioned, the less marked differences of relative size in D. CONGDON n of cervical ve the same ebral column of is in figure 4 | vertebral column of younger con- ibnormal SKELETAL DEFORMITIES IN A YOUNG. FOWL 171 other regions make it difficult to decide which if any of these have normal measurements. The wattles, comb, and bill indicate maturity equal to the older control bird, whose body is twice as large as that of the abnormal cockerel, and was chosen from a number of equal maturity as representing their average size. Since the skull of the deformed bird appears to be normal except for the deformity due to pressure against the roof and is of almost the same length as the control, it may be the birds would have been of equal size as well as maturity, had conditions been normal. The measurements of the skeleton of the extremity are un- fortunately limited to the femur and the coracoid. Both agree closely in length with the smaller control. The appearance of the extremities in figures 2 and 3 confirm this view. The only careful observations of the bone form in these regions were upon the tibiofemoral joint. Here no retardation of development could be noticed. Comparative measurements of abnormal cockerel, large and small control and rooster eo | a AVERAGE MEASURE- al a eon MENTS OF ENTIRE 8§ z ak CERVICAL VERTE- as a a BRAL COLUMN oac oA za 28 < *a oe 3 fee | eben ess = 2 One 268 ro] 25 = ee . a eer Rn R< z= ou seis 5 BS 3 Ss. (Se. QS ° Be of 23 524 ae a<6 = eS | sf | 85 |Fs2s See z za .| #2 | 38 |S2E8 ome g as 5S go |goae & a <] ra m — cm cm, cm, cm, cm, cm. Abnormal cockerel.............- at ey 6.7 6-7 | 0.98 | 0.62 | 1.24 4 ~ Younger control (10 months old).| 12.0 6.5 6.7 | 0.91 | 0.54 | 1.15 Older control (13 months old)....} 14.0 6:Sen) 10.1. | 0.93 |: 0.54 | 1.10 OOSDC Lae eceer re cic ts ana ons 20.0 8.0 1S 6) 1227 0:61. | 1.49 The cervical column has plainly undergone an excessive devel- opment in volume, since, as seen in the accompanying table, it is not only larger than the older control in three measurements which were chosen, but it even slightly exceeds a rooster in the minimum transverse diameter of its centrum. The upper verte- brae are especially large and the atlas largest of all (fig. 6.) These facts together with the correspondence, of the limb skeleton in 172 P E. D. CONGDON length with the smaller fowl and its lack of abnormal characters lend some support to the view that the younger control may represent the true size of the deformed bird, had it developed normally and that there has been an overgrowth of skull as well as cervical vertebral column. ‘The less sharply sculptured sur- face and the more massive form is found in the cervical column, which has been frequently described in other instances of over- growth. The skull did not show a similar condition, but its comparative freedom from surface elevations would prevent easy recognition of a slight deficiency in this respect. in psi a, ax ‘ ae. ia ns 7 fl nyti. on & Bina i). s) cau prey tah ‘# a GTi tt aH) Ro al! ati uit Ob tu ; 1} (/ Mars ie “yiiers ni fi i] batiola: bugle Le ahi ~ 3 ; A t i Piva Ui} hatla i a oil "i idee ee) Nh? A hi it ms! Vy Wiis ith “alr 71] Rvs hi yy, be ee Ri Mi! e., Ae’ "leis he *)%, Pe viiL| mY a ae ily ie inte Ad oo Rui f hy tt 4 a 4 ae Wie hp 10 bette hey Die) Ve Mia As Aaa itil ak? lai rut Tey ii? + bia. ks J T en uh, Dra. \on ver 1 i | vil ‘Wah iae'! in or; patiyy yw TAl * sid 8 was \\ Abstracted by Francis Marsh Baldwin, author. Iowa State College. Notes on the branches of the aorta (arcus aortae) and the sub- clavian artery of the rabbit. Although the usual number of blood-vessels arising from the — aorta in the rabbit is two—a so-called innominate or brachio- cephalic and the left subclavian arteries—the variation from this — condition herein described indicates the possibility of a consid- erable departure. Of 106 specimens, about 20 per cent differed from what is usually considered normal, either in respect to the aortic vessels or the subclavian arteries of either side. In one individual a single vessel leaves the arch of the aorta, and after passing forward subsequently successively subdivided to form the left subclavian, the left common carotid, and the innominate or brachiocephalic arteries. When three vessels originate on the arch, they are usually the innominate and the two carotids, although in one case the vertebral of one side contributed to this arrangement in the place of a carotid. Several individuals show conditions suggestive of four vessels, comprising the two carotids, the left vertebral and left subclavian. The order and sequential differences of vessels from the subclavian arteries of each side are noted. AUTHOR'S ABSTRACT OF THIS PAPER ISSUED BY THE BIBLIOGRAPHIC SERVICE, JUNE 21 NOTES ON THE BRANCHES OF THE AORTA (ARCUS AORTAE) AND THE SUBCLAVIAN ARTERY OF THE RABBIT FRANCIS MARSH BALDWIN Iowa State College, Department of Zoology, Ames, Iowa ELEVEN FIGURES (ONE PLATE) Bensley,! in his Practical Anatomy of the Rabbit (p. 365), in discussing the blood-vessels of the thorax, describes the arch of the aorta as ‘‘beginningat thebas@oftheheart, . . . . . passes forward, and then describing a curve, in the course of which it lies slightly to the left of the median plane, turns backward along the ventral surfaces of the bodies of the thoracic vertebrae. With the exception of the coronary arteries the first branches are the large paired vessels arising from the anterior wall. They comprise the common carotid and subclavian arteries. On the right side the carotid and subclavian arise from a,short common trunk, the innominate artery. The left common carotid arises immediately to the left of this vessel or from its base. The sub- clavian artery (a. subclavia) is the first portion of the artery of the anterior limb. It passes from its point of origin laterad to the anterior margin of the first rib, where it is-replaced by the axillary artery. Near its point of origin, it gives off several branches, the relations of which are subject to considerable variation.” The large paired vessels referred to above is not exact and leads to confusion, since even in the usual condition it applies to neither the right and left common carotid arteries, nor the paired subclavian arteries, but to an innominate artery on the right side, and the left subclavian artery on the other. That the left common carotid artery usually arises immediately to the left 173 174 FRANCIS MARSH BALDWIN of the base of the innominate is perhaps correct, although in by far the greater number of rabbits dissected the origin of this vessel is well up on the mesal side of the innominate. In cases where the left common carotid artery arises to the left of the innominate, there would be three vessels arising from the ceph- alic curve of the aorta and not two (a pair) as above described, a condition normally found in the human. With reference to the subclavian arteries, the statement as to their branches being subject to, considerable variation, is correct, but it seems important that the point should also be made, that great differences occur in these vessels on the right and left sides in the same animal. Again, Parker and Haswell? describe correctly the relation of these vessels as they occur in the majority of cases, but the figure shown (p. 465) represents the condition in an abnormal individual, where the left common carotid artegy originates as a branch from the arch of the aorta, and thus constitutes the third vessel from the arch, the innominate and the left subclavian being the other two. Since these discrepancies exist in the descriptions of the blood-vessels of the region in the various texts, and in view of the variability of both the arteries given off by the arch of the aorta, and their subsequent subdivisions, especially those of the subclavian, it seems of sufficient interest to record their frequency and extent. Accordingly, the following description is based upon the study of over one hundred specimens. Such records, of course, have no immediate practical value from the surgical or pathological sides, but from the educational consider- ations, especially from the standpoint of comparative anatomy they are rather important. No doubt the variations which are described below are to be explained in part by the persistence of foetal conditions, or in some cases by abnormalities of the vessels themselves, or to the development of extrinsic parts in their immediate region. Many of the changes brought about are probably due to different modes of transformation of the primary vessels of the branchial arches, especially the fourth, since the aorta as well as the pulmonary artery are derivatives of this arch. Again, it is well known that the heart itself origi- nally develops high up in the neck region of mammals, and is AORTA AND SUBCLAVIAN ARTERIES OF THE RABBIT 175 gradually shifted downward, so that this gradual shifting might account for some of the variations noted. Of one hundred and six rabbits dissected* nineteen individuals showed marked variations from the usual condition, either in the branches from the aorta, or in respect to the subclavian and its branches in either side. There were others (fifteen) which showed minor variations, but which could easily be placed in some of those showing marked variations, so that their condition is represented, partially at least, in some one or in a composite of the subjoined figures. In what may be termed the usual condition, the aorta (fig. 1, A), after giving off the coronary arteries close to its junction with the left ventricle, passes cephalad a short distance, and then describes a curve of a half cirele and passes down the back, a little to the left of the ventral vertebrae. From the cephalic eurve (arch) a comparatively large innominate or brachioceph- alic artery extends upward and a little to the right and soon bifurcates, forming the left common carotid artery which passes immediately across the trachea to the left side of the neck, and a common trunk which gives rise to the right subclavian and the right common carotid arteries. A second branch from the curve of the aorta is the left subclavian artery which passes laterad and forward to branch in various ways. Usually on this side the superior intercostal (costocervical) (fig. 1,7) is the first branch to be given off, and passes caudomediad. Just distal in close juncture with the superior intercostal artery is the internal mam- mary artery, while just opposite arises the vertebral artery. Distally the subclavian artery soon divides into the transverse scapular (7’) and the axillary (X) arteries. On the right side the superior intercostal and mammary arteries arise from a common trunk, as also do the vertebral and transverse scapular arteries just opposite to them. The axillary artery passes to the region of the forearm. In some cases the superficial cervical artery branches from the subclavian, but usually it is a branch of the transverse artery of either side. * My thanks are due Mr. Ralph L. Parker, my assistant, for aid in dissection. 176 FRANCIS MARSH BALDWIN VARIATIONS OF THE SUBCLAVIAN ARTERY OF THE LEFT SIDE A number of interesting variations are noted in the order and sequential relationships of the various vessels arising from the left subclavian. Frequently the arteries originating from the subclavian artery in close proximity to each other so that a veritable corona of the vessels is formed. In some cases, as shown in figures 6 and 11, this takes place at quite a distance from the arch of the aorta, and can be called the long corona type, while in others, typified in figures 9 and 10 and perhaps less conspicuously in figure 8, the corona formation is closely approximated to the aortic arch. Where the corona is formed, the usual order of the vessels may be described as normal, i.e., beginning with the vertebral artery originating on the cephalo- mesal surface of the subclavian, the transverse scapular, axillary, mammary, and intercostal arteries followed in the cycle clock- wise. In one specimen an interesting departure is noted, in that the intercostal artery (fig. 6, 7) takes its origin from the vertebral so that there is formed in this case a very short innomi- nate with the vertebral artery. A number of cases are observed where the intercostal and mammary arteries formed a short innominate in common as is shown in figures 4 and 7. In one rabbit (fig. 3 V) the vertebral artery of this side branches from the cephalic surface of the arch of the aorta at about its junction with the subclavian artery, and in this case it is comparatively a much larger vessel than normal. In this specimen also the transverse scapular and mammary arteries have their origin some distance cephalad, and the interval between the intercostal and mammary arteries is very noticeable. In no ease is there found an innominate formed by the left subclavian and the left common carotid arteries, which of course is the typical avian condition, and which has been described to occur in most apes, and somewhat more rarely has been noted in the human. In three cases, however, varying in degrees, as shown in figures 6, 8, and 10, the left common carotid artery is a separate branch from the arch of the aorta, and in these the condition closely simulates the normal condition found in the human. In one in- AORTA AND SUBCLAVIAN ARTERIES OF THE RABBIT 177 stance the points of origin of the vertebral and the transverse scapular arteries are interchanged, as shown in figure 2, and in another, figure 5, the vertebral artery arises from the laterocaudal surface of the subclavian in the same manner but distal to the intercostal and mammary arteries, and then turns mesal to enter the transverse foramina of the cervical vertebrae. In the last specimen also a number of excessory blood-vessels are noted, some of which parallel the mammary, others the intercostal arteries. THE SUBCLAVIAN ARTERY OF THE RIGHT SIDE The blood-vessels of this side which take their origin from the subclavian artery seem less variable in their relationships than those just described. There is the formation of what may be termed a corona in several instances, but this is with but one exception formed relatively close to the innominate, or to that portion close to the bifurcation of the innominate which forms the subclavian and right carotid arteries. Such a condition is typically shown in figure 5, where the vessels spread out in fan- shape formation about the subclavian. In one instance, the vertebral artery (fig. 2, V) originates well cephalad and on the lateral surface of the right common carotid artery, so that its displacement from its usual position is rather striking. As re- gards the interrelation of the intercostal and internal mammary arteries, all sorts of gradations of intervals exist from the for- mation of a conspicuous elongated innominate, as is indicated in figure 3, or a much-reduced innominate, as shown in figure 11, to the more or less widely separated intervals, as represented in figures 8 and 9. The intercostal artery in the last case is really a branch of the innominate, and has no connection with the sub- clavian. Usually the superficial cervical artery of this side as in the normal condition is a branch of the transverse scapular artery, but in two cases it is greatly displaced; one originating from the subclavian (fig. 3) and another curiously entering the common junction of the intercostal-mammary vessels, as shown in figure 10. In one case the transverse scapular artery originates as a branch of the vertebral well cephalad of the latter’s 178 FRANCIS MARSH BALDWIN junction with the subclavian, as in figure 8, although in two other specimens this condition is barely suggested in the close prox- imity of the origins of the two vessels, as in figure 9. The manner of branching of the two carotid arteries from the innominate is of interest, although not more variable than might be expected. In the majority of specimens showing differences in other respects, the two carotid arteries branch well up on the innominate. Inseveral cases the point of origin of the left common carotid artery is close to the curve of the aorta, and in three cases (figs. 6, 8, and 10) the junction is really on the arch, thus giving rise to an additional vessel in these cases, as indicated above, which simulates very closely that found normally in the human. Three individuals (figs. 7, 9, and 10) show the formation of a thyreoid ima, so-called, a small vessel arising on the innomi- nate between the right and left common carotid arteries, which passes forward to the thyreoid gland and gives off small vessels to the neck muscles of the region and to the trachea. Its point of origin varies somewhat in the three animals, but morpho- logically it bears the same position as has been described for a similar vessel in the human (MeMurrich,* p. 511.), i.e., it passes forward from the innominate between the common carotid arteries of either side. It should be said, however, that since the common carotids of either side in man differ slightly in their points of origin from those in the rabbit, the formation of this vessel in the rabbit does not contribute to the formation of a fourth vessel arising from the erch of the aorta, as isthe case inman, but does form a fourth vessel from the innominate. In asingle case, as shown in figure 11, the arch of the aorta gives rise to but one vessel, an innominate, which passes cephalad for some distance before it breaks to form, first, the left subclavian, and a little further forward the left common carotid artery, and the brachiocephalic artery. This peculiar variation is interesting, since it closely simulates the normal condition found in the horse. It may be explained by the fusion of the two aortic stems and the shortening of the fourth arch so that the left subelavian artery joins with the com- mon stem during the transformation of the primary vessels. In one instance the left vertebral (fig. 3, V) takes its origin well AORTA AND SUBCLAVIAN ARTERIES OF THE RABBIT 179 down on the left subclavian vessel so that it is almost in a posi- tion to be considered a separate branch from the arch of the aorta and could be interpreted as an additional vessel from the latter as has been recorded as a variation in the human (MeMur- rich, p. 511). It is easy to see how by a slight displacement caudad of the left common carotid artery in this case would produce four distinct vessels originating from the arch of the aorta instead of the usual two. SUMMARY Although the usual number of blood-vessels arising from the arch of the aorta in the rabbit is two—a so-called innominate or brachiocephalic artery and a left subclavian artery—the varia- tions from this condition herein described indicate the possibility of a considerable departure. In one individual (fig. 11) a single vessel leaves the aortie arch, and after passing a short distance forward subdivides successively to form the left subclavian, the left common carotid, and the innominate or brachiocephalic arteries, the latter subdividing again to form the right common carotid and the right subclavian arteries. In a number of cases, as shown in figures 6, 8 and 10, three vessels have their origin on the arch, and in these the order is the brachiocephalic, the left common carotid, and the left subclavian arteries. In one individual (fig. 3) the left vertebral replaces the left common carotid artery in the series, the carotid in this case having its orgin on the innominate as normally. This case suggests the possibility of four vessels forming the series. Conspicuous differences in the order and sequence of the ves- sels from the subclavian arteries of the two sides are noted. On the left side the vessels in a number of cases show a tendency to group themselves either proximally or distally in the form of a short corona, as indicated in figures 6,9 and 10. The formation of various innominate stalks common to certain arteries are found in some eases, while in others the intervals between certain arteries are rather noticeable. Less marked variations are noted in the vessels of the right side. The vertebral artery in 1S0 FRANCIS MARSH BALDWIN one instance (fig. 2) is displaced from its usual place to the lateral side of the right common carotid artery. The transverse scapular artery in two cases is a branch of the vertebral, while the super- ficial cervical, which is normally a branch of the transverse scapu- lar, in one case (fig. 10 ) leaves the subclavian as a common stalk with the intercostal and mammary arteries. In three cases a small so-called thyreoid ima is present, and in these this passes forward from its origin between the two common carotids, thus having the same morphological position in the rabbits as a similarly described vessel occupies in the human. LITERATURE CITED 1 Benstey, B. A. 1918 Practical anatomy of the rabbit, 2nd edition, pp. 256-257. Univ. Toronto Press. 2 Parker anp Haswett 1910 Text-book of zoology, 2nd edition, vol. 2, pp. 464-465. MacMillan Co. 3 MeMurricn, J. P. 1906 Morris’s human anatomy, 4th edition, pp. 510-511; 556. P. Blakiston’s Sons & Co., Phila. AORTA AND SUBCLAVIAN ARTERIES OF THE RABBIT 181 PLATE 1 EXPLANATION OF FIGURES 1 Diagrammatic ventral view of the arteries of the thoracic region of the rabbit, showing the various branches as they occur in the majority of speci- mens. The innominate (brachiocephalic) (N) and the left subclavian (8) are the two usual branches of the arch of the aorta. The left subclavian gives origin to a number of arteries as here shown, while the innominate bifureates to form the two common carotids and the right subclavian arteries. 2 Schematic ventral view of the arteries of rabbit 32, which conspicuously indicates the vertebral artery of the right side as a branch of the right carotid artery. Notice on the left side the transverse scapular and the vertebral arteries are morphologically interposed and the intercostal and mammary arteries are separated by quite an interval. The left common carotid is well down at the base of the innominate, almost constituting a separate branch of the arch of the aorta. 3 Ventral view of the arteries in rabbit 40. The vertebral artery of the left side is here formed close to the junction of the subclavian with the aortic arch, and thus forms what may be considered a third branch of the arch. The inter- costal and mammary arteries of the left side are separated by a wide interval. 4 Rabbit 53 shows the formation of common stalks (innominates) for the intercostal and mammary arteries of both sides as well as the transverse and superficial cervical of the right. The brachiocephalic gives rise immediately to the left common carotid. 5 The arteries of rabbit 22 show differences in branches of the right and left subclavian vessels especially. The intercostal and mammary arteries ‘originate separately on the right, the vertebral on the left is well cephalad of the other vessels, and makes a bend caudomesad as here shown. Accessory vessels are found on the left side also. 6 In rabbit 28 the formation of what may be termed a long corona of the left subclavian with a migration of the intercostal from the lateral surface of the subclavian to form a common stalk with the vertebral artery. The left com- mon carotid artery is here a branch of the aortic arch so that three distinct branches are formed. The innominate is conspicuously long. 7 Specimen 19 shows among other variations the formation of the thyreoid ima, a small vessel originating on the innominate just caudad to the point of origin of the left common carotid artery and passing forward to the thyreoid gland of the neck. 8 Rabbit 21 shows interesting relationships of the innominate, left common carotid, and left subclavian arteries, and shows the comparatively immediate subdivision of the subclavian of either side. Such a condition may be designated as the short corona type. 9 Specimen 106 shows the so-called thyreoid ima and other minor variations especially in the interval between the intercostal and mammary arteries of the right side, and the formation of the short corona type of the left subclavian artery. THE ANATOMICAL RECORD, VOL. 19, NO. 3 182 FRANCIS MARSH BALDWIN 10 In rabbit 85, beside the thyreoid ima being present, the left subclavian takes its origin on the arch and the superficial cervical of the right side passes out from the common stalk of the intercostomammary artery. The subclavian of the left side forms a short corona. 11 In rabbit 52 the innominate (brachiocephalic) artery is the only vessel originating on the arch of the aorta, and subsequently subdivides as shown, giving rise to a long corona typed left subclavian, left and right carotid arteries, and right subclavian artery. This condition thus typifies that found normally in the horse. ABBREVIATIONS AS aorta, with its ascending, trans- M., internal mammary artery verse arch and descending (dorsal) S., subclavian artery, right and left portions T., transverse scapular artery, in- C., common carotid arteries, (R) right cluding the superficial cervical and (L) left artery I., superior intercostal artery V., vertebral artery, right and left H., heart X., axillary artery, right and left N., innominate artery AORTA AND cee ae ARTERIES OF THE RABBIT PLATE 1 CIS MARSH BALDWIN Abstracted by Joseph M. Thuringer, author. Tulane University of Louisiana. A suggestion for improvement in projection and drawing apparatus. By substituting a focusing stage in the drawing apparatus, provided with coarse and fine adjustments, in place of the fixed stage used at present, variations in the magnification of the pro- jected image due to focusing are eliminated, hence more accurate results in reconstruction work may be expected, even when slides and cover-glasses in a given series are not of uniform thick- ness. ‘The customary arc lamp is discarded for a new commer- cial form of incandescent illuminant which greatly facilitates the control of the light. AUTHOR'S ABSTRACT OF THIS PAPER ISSUED BY THE BIBLIOGRAPHIC SERVICE, JUNE 21 A SUGGESTION FOR IMPROVEMENT IN PROJECTION AND DRAWING APPARATUSES JOSEPH M. THURINGER Department of Anatomy, Tulane University of Louisiana, New Orleans, Louisiana ONE FIGURE Among the various types of apparatus manufactured for the projection of microscopic objects for tracings and drawings, the Edinger drawing and projection apparatus no doubt holds first place, both from a point of usefulness and of mechanical stability. For thé drawing of individual microscopic objects it leaves little to be desired, except perhaps an improved form of illuminant. However, when used for the drawing of serial sections for recon- struction work by any of the various methods in vogue, we are at once confronted with a little more difficult problem. It is highly desirable to hold the percentage of error in recon- struction work toa minimum. A well-prepared series of sections, of course, is the essential factor. Secondly, this series should be mounted with slides and cover-glasses of uniform thickness. Even the mounting medium should be of uniform consistency and temperature for a given series, and all the slides after mounting subjected to a drying for a given number of hours at uniform tem- perature to insure an absolutely equal distribution of the mounting medium over the entire surface. With all these precautions carefully observed, there still remains an appreciable source of error due to the difference of magnification obtained when using the present focusing devices. The slightest change in position of the draw-tube alters the magnification. To increase the efficiency of the above-mentioned apparatus the following changes are suggested and illustrated in the accompanying drawing. The stage as manufactured at present is only equipped with a clamp (dk) for altering its position. This, however, does not 185 186 JOSEPH M. THURINGER permit sufficiently convenient and accurate adjustment to an- swer the purpose of a focusing stage. The most painstaking care in the determination of the magnification by means of stage micrometer and rule will be upset by the slightest change in position of the draw-tube or by having to refocus. To obviate this source of error the focusing stage illustrated (S) is suggested It is equipped with a coarse and fine adjustment identical with the one supporting the draw-tube of the microscope (M) and therefore not entailing great additional cost in the manufacture. This stage could also be supplied to all Edinger apparatuses in present use, thereby bringing them to their highest efficiency. After the desired magnification is once determined, all future adjustments are made by means of the stage coarse and fine adjustments. All errors due to differences in thickness of slides, cover-glasses, and mounting media are thus compensated. The condenser (C’’) is hinged on a support and guided by an upright which, however, is not secured to the stage, as at present, thus permitting more room for the use of a mechanical stage. The are lamp, which always required more or less attention and needed new carbons at the most inopportune moment, is here replaced with the new low-voltage, high-amperage, concen- trated-filament, incandescent lamp. On direct current this is operated in series with a suitable resistance and on alternating current with a small transformer. Both of these devices can be attached under the drawing table and require no further attention when once adjusted. The lamp is held by a universal support (U), which allows adjustment vertically as well as horizontally, thus permitting the use of various-sized lamps. A light-tight, ventilated hood, provided with an adjustable reflector (22), completes the outfit. IMPROVEMENT IN PROJECTION APPARATUSES 187 Fig. 1. Diagram of projection and drawing apparatus. C”, stage con- denser; C’, condenser; L, lamp in ventilated housing; FR, adjustable reflector; U, universal support; S, focusing stage; K, clamp; M, microscope. Abstracted by James C. Watt, author. University of Toronto. Symmetrical bilateral dystopia of the kidneys in a human sub- ject, with outward rotation of the hilus, multiple arteries and veins, and a persistent posterior cardinal vein. In a male human subject, aged twenty-eight, who died of pulmonary tuberculosis, an associated series of rare anomalies of the kidneys was found. There was a symmetrical bilateral dis- placement caudally, each kidney lying from the level of the second to the fifth lumbar vertebrae. Symmetrical displace- ment without fusion is rare. The hilus forms a long, narrow groove, the upper part lying on the anterior surface of the kid- ney, the remainder describing a spiral cutting around the outer border on to the posterior surface as it proceeds caudad. This lateral position of the hilus is extremely rare, previous ones being found in pelvic kidneys, and very few instances being recorded. On the right side were five renal arteries, two off the aorta, three from the common iliac artery. There were four left renal arteries, two from the aorta, one from the common iliac, and one from the hypogastric arteries. ‘Two spermatic arteries were present on the right side and three on the left. Two renal veins, uniting into a short common stem tributary to the inferior vena cava, occur near the upper pole of each kidney. In addition, on the left is a posterior cardinal vein connected at the ends to the common iliac and upper renal veins and having as tributaries a third renal vein and four lumbar veins. A fourth left renal vein goes to the hypogastric vein. The pelvis of the ureter enters the kidneys anterior to the main vessels. The ureter courses lateral to the kidney. AUTHOR'S ABSTRACT OF THIS PAPER ISSUED BY THE BIBLIOGRAPHIC SERVICE, JUNE 21 SYMMETRICAL BILATERAL DYSTOPIA OF THE KIDNEYS, IN A HUMAN SUBJECT, WITH OUTWARD ROTATION OF THE HILUS, MULTIPLE ARTERIES AND VEINS, AND A PERSISTENT POSTERIOR CAR- DINAL VEIN JAMES CRAWFORD WATT Department of Anatomy, University of Toronto TWO FIGURES In the laboratory of the Department of Anatomy of the University of Toronto a very interesting series of associated anomalies relating to the kidneys and their vessels was discovered during the regular course of dissection. The specimen was at once put aside for investigation, and on further study has been considered worthy of a detailed description. The body was that of a well-proportioned but somewhat emaciated male, aged twenty-seven, who died of pulmonary tuberculosis. Apart from the abnormalities associated with the kidneys, no other gross anomalies were noticed in this subject. THE KIDNEYS Shape and size (fig. 2) The outline of the kidneys is that of a long, narrow oval. The ventral surface is quite convex, the dorsal surface flattened. Of the two poles, the lower is much thicker than the upper. A shallow groove winding spirally from the ventral surface laterally and caudally on to the dorsal surface forms the hilus, and notches the outer border where it crosses it. Except for the presence of the hilus, the surface is smooth, and shows no special lobulation. 189 190 JAMES CRAWFORD WATT The measurements taken are as follows: Right kidney Left kidney Greatest lengths... .5 is Cedivassar es scices 10.5 em. 11 cm. WiGUNS «. dete acies ce sone teiivic ols eoteey 3.5-4.5 em. 3.5-4.5 em. Thidkn oss eel. 5 vs cee nae ssa essere 2.5-3.5 cm. 2.5-3.0 cm. Position and relations (fig. 2) The two kidneys exhibit a displacement which is quite sym- metrical on both sides. Each lies close in against the psoas Inferior Vena Cava : Suprarenal Artery Three Left Spermatic Arteries ‘and one Vein Right Commen Renal eun Firat Right Renal Arter. , 1! nd Y and Vein First Left Renal Artery and Vem Second Right Reral Artery and Vein Two Right Second Left Renal Artery and Vein one Vein Hilus fF Fourth Left Renal Artery p and Vein Third, Fourth and Fig th -@ Right Renal Y Arteries Lett Ureter Hypopastric fale and Vein Left External linac Artery and Vern Fig. 1 Outline drawing of the kidneys and their vessels and ureters. Veins are solid black, arteries striped, and ureters stippled. Lower part of right kidney removed. major muscle and shows the same degree of obliquity as the muscle. The upper pole of each kidney is about 1 cm. nearer the midline than the lower pole. The upper pole is opposite the middle of the second lumbar vertebra, the lower oposite the lower part of the fifth lumbar. The kidney thus lies with its upper portion in the lumbar region, on the quadratus lumborum muscle, the other portion in the iliac fossa, on the iliacus muscle. The suprarenal glands were placed over the upper pole and slightly to the medial side of each kidney. The left gland was RARE ANOMALIES OF THE KIDNEY 191 situated in a small space with the kidney below, pancreas above, spleen laterally and vertebrae medially. Fig. 2 Drawing of the kidneys to show their relations to the dorsal abdominal wall and the viscera. The duodenum, pancreas, and spleen have been retained in position, the lower part of the duodenum being hooked up to expose the under- lying vessels. The suprarenal glands have been removed to expose the upper * pole of the kidney. Lower part of right kidney removed. The pancreas was situated entirely above the left kidney and crossed right over the spleen. Owing to the downward dis- placement of the kidney, the spleen was displaced inward and 192 JAMES CRAWFORD WATT was in contact with the vertebrae medially for two-thirds of its length. The lower pole, however, had the upper pole of the kidney inserted between it and the vertebral column. On the right side the kidney and suprarenal gland lay entirely below the level of the liver, which was thus allowed to come into contact with the diaphragm on its posterior surface. The upper pole of each kidney and the common renal vein from each side were under cover of the duodenum at the flexure of the latter at the lower end of the descending limb. The hilus (fig. 2) The position of the hilus is most interesting, and is quite sim- ilar on both sides. Starting above, about three centimeters below the upper pole, on the anterior surface, it runs obliquely caudad to cut the lateral border of the kidney, forming a notch on it about two thirds of the way down. It then curves from here on to the posterior surface, ending about two or three centi- meters from the lower end of the kidney. The hilus is thus placed on the opposite border to the normal — and forms a spiral with gradually increasing rotation about the polar axis as it proceeds caudad. VESSELS Arteries (figs. 1 and 2) The renal arteries and also the spermatic arteries of both right left sides are multiple. Right side. The right renal arteries are five in number. The first comes off the abdominal aorta at the level of the second lum- bar vertebra and goes behind the inferior vena cava to the upper end of the hilus on the anterior surface of the kidney. The second renal artery also goes to this surface, coming from the aorta at the level of the third lumbar vertebra and running in front of the vena cava. Off the right common iliac artery come the third renal artery, a very small one, the fourth, quite large and dividing early into RARE ANOMALIES OF THE KIDNEY 193 two, and the fifth, a small artery again. These three arteries running in close company pass behind the lower pole of the kid- ney and enter the lowermost part of the hilus on the posterior surface. The right spermatic arteries are two in number. The higher one arises from the aorta between the first and second renals, and runs posterior to the inferior vena cava and both renal veins, but anterior to the upper pole of the kidney. The lower artery arises from the second renal, goes posterior to the inner renal vein, anterior to the outer vein, and anterjor to the kidney. At the lateral border of the kidney the two spermatic arteries and the vein form a common bundle running in contact with this border and the ureter in the iliac fossa, and then turning over the psoas muscle to the internal abdominal ring. Left side. There are four left renal arteries. The first is off the aorta at the upper limit of the second lumbar vertebra and runs down anterior to the upper pole of the kidney. The second artery is from the aorta, over the second lumbar vertebra, level with the highest artery on the right. It is also to the hilus on the upper part of the anterior surface of the kidney. The third left renal artery is off the left common iliac, and is peculiar in that it runs across the upper part of the iliac fossa behind the kidney, to pass into the hilus just where it cuts across the lateral border. The fourth artery is off the internal iliac, or hypogastric artery, just at its commencement, and runs anterior to the external iliac artery and psoas major muscle and penetrates the kidney on its medial border just near the lower pole. On this side there are three spermatic arteries, the highest coming off a suprarenal branch of the first renal, the other two directly off the first renal. All three arteries and the spermatic vein form a common bundle coursing anteriorly along the lateral border of the kidney, then lateral to the ureter in the iliac fossa and down to the inguinal canal. 194 JAMES CRAWFORD WATT Veins (figs. 1 and 2) Right side. There are two renal veins, both coming from the upper part of the hilus over the anterior surface of the kidney, and uniting at the level of the upper pole of the organ into a com- mon vein which is about three-quarters of an inch in length and empties directly into the inferior vena cava. The right spermatic vein, a single vessel, opened into the lat- eral of the two renal veins. Left side. On this side are three renal veins. Two are quite similar to those on the right, arising from the anterior surface of the kidney on the upper part of the hilus and uniting into a com- mon stem which crosses anterior to the aorta and empties into the inferior vena cava. Just at the junction of the above two veins, there comes into the medial one, a longitudinal vein which lies over the front edge of the psoas muscle, on the vertebral column, in the interval between the aorta and the left kidney. This stem starts at the level of the fifth lumbar vertebra, and communicates with the left common iliac vein below. As it ascends it receives as tribu- taries four lumbar veins, one of which is double, and also a renal vein. This renal vein comes from the hilus where the latter cuts the outer border of the kidney, and runs medially posterior to the kidney, alongside of the third renal artery, and ends in this ascending vein. This longitudinal stem is interpreted as a persisting portion of the embryonic posterior cardinal vein of the left side, which lies exactly in the position occupied by this present vein. The left spermatic vein, single in spite of the presence of three arteries, empties at the junction point of the two large upper renal veins into the common trunk. Ureter (figs. 1 and 2) The position and relations of the ureter are remarkably sym- metrical on the two sides. At its pelvis, each ureter is divided into two parts. One is a long, narrow, tubular portion which lies in the upper part of RARE ANOMALIES OF THE KIDNEY 195 the hilus, on the anterior surface of the kidney. The other is a broad, short, funnel-shaped portion communicating with the kidney in the hilus just before the latter cuts round the outer border, of the organ. The two parts unite at the lateral border of the kidney, which the ureter now follows to the lower pole, where it then crosses the iliac fossa, turns medially over the psoas muscle and external iliac artery into the pelvis, where its course into the bladder is normal. The highest artery and the lateral vein accompany the upper branch of the ureter as it enters the kidney, the vessels lying behind. The other vessels enter the kidney mostly behind the lower branch of the ureter. SIMILAR CASES Multiple renal arteries and veins in all the locations found in this case have been previously described and discussed by various authors, and so call for no special consideration. Tonkoff (03), for instance, describes and gives a figure of a right kidney slightly displaced downward and with an arrangment of its four renal arteries almost identical with those of the left kidney in this case. Macalister (’83) and Morris (’85) both state that abnormal vessels occur in three individuals out of every seven. The occurrence of a vena cardinalis posterior along with renal anomalies has been noted before. Melissinos (’11) found a case of pelvic kidney with a persistent right cardinal vein, and gives reference to a few other instances. The presence of the rotation seen in these kidneys, on the contrary, is evidently quite a rare condition. Among the anom- alies of position of the hilus, the particular one exhibited here is not even mentioned in the text-books on pathology or surgery. It is self-evident that such a position would be of great interest, especially to the surgeon. Gerard (’05), in a review of 527 cases, states that the renal hilus, instead of lying medially, may be superior, inferior, ventral, or dorsal, but does not mention any instance of a lateral position. 196 JAMES CRAWFORD WATT Miillerheim (’02) describes a case where the left kidney was. found in the pelvis, with its hilus not medial, but anterior, and he states that one of the characteristics of dystopia of the kidney is that the hilus is usually anterior in position. Morris (’04), in a summary of displacements, states that the kidney may be rotated so that the hilus looks upward, outward, directly forward or backward, and mentions one case of the hilus occurring laterally. This case was described by Farquharson (’94) as a left kidney placed in the pelvis with hilus looking to the left. Brown (’94) also describes a right pelvic kidney which had rotated till its posterior surface had become anterior and the hilus looked posteriorly to the right. Johnson (’14) deseribed a case in the cat exactly similar to that of Brown’s and Anitschkow (712) describes and gives a figure of a left kidney in man displaced slightly back in the lumbar region and with a hilus which he describes as anterior, but which, in the illustration, appears to course around the lateral border, as there is a marked indentation shown there. MeMaurrich (’98), considering a series of crossed dystopia of the kidneys with fusion, pointed out that in nearly all cases the position of the hilus was anterior. This retention of an anterior position of the hilus in displace- ments and in fusions.of the kidneys is the retention of the normal embryological position. Pohlman (’05) noted that until the kidney had ascended in the embryo to where it was approxi- mately in the adult position, the hilus was ventral, and then a rotation medially of 90° occurred about the polar axis. Felix (12) also states that this rotation occurs, but that a reverse rotation toward the ventral surface also occurs later, so that the hilus is finally ventromedial. The kidneys in the present case have not reached the usual final level and so might be expected to have retained the hilus anteriorly. ‘This is true of the upper part, but the lower portion exhibits the rare outward rotation through 90° to bring it laterally, and the lowest part goes even further than this to lie posteriorly. There is thus considerable torsion in the kidney, the hilus forming quite a spiral in its course. RARE ANOMALIES OF THE KIDNEY 197 The fact that the ureter lies ventral to the main renal vessels at the hilus at first sight appears as an anomaly. It will be seen, however, that if the hilus were to be rotated into its usual position the ureter would then lie posterior to the vessels. Thus at their entrance into the kidney these structures stand in their normal relations to each other, but the rotation makes them appear reversed. The position of the suprarenal glands is interesting. MeMur- rich, Morris, Millerheim, and others have all stated that the relation of these glands to the kidneys is merely topographical and that they are found in their usual places in cases where the kidneys are displaced. In this instance, however, they lie closely capping the upper pole of each kidney, and so are displaced some- what caudally from their normal location. What was the actual cause of all the anomalies shown above is open to conjecture. It must have been a force acting in early embryonic life. The displacement into the iliac fossa was prob- ably due to lack of growth in the ureter and the torsion due to a twisting of the pelvis of the ureter. It is of interest to note that Felix (12) states that in the lumbar region the ureter shows a dilatation accompanied by a spiral twisting. An exaggeration of this process might possibly account for the result shown here. Whatever the cause may have been, the result is most remarkable for instead of a symmetrical displacement of the whole organ, we have here the upper pole with the upper end of the hilus facing still in the old embryological position, while proceeding caudad there is an ever-increasing torsion evident, until finally at the lower end the hilus shows a displacement of 180° brought about by lateral rotation. The position of the kidneys in the lower lumbar region and iliac fossa seems to be a much rarer condition than the position within the pelvis, as by far the greatest majority of cases of dystopia without fusion are reported as being in the pelvis. The symmetrical degree of dystopia shown by these two kid- neys seems to be almost as rare a condition as the lateral hilus. In all the cases quoted above and in many others not mentioned here, if the two kidneys are not fused to form the discoidal or the THB ANATOMICAL RECORD, VOL. 19, No. 3 198 JAMES CRAWFORD WATT horseshoe kidney, either there is a much greater degree of dystopia on one side than on the other or else only one kidney shows dis- placement, the other being in its normal position. Thus the kidneys in this instance are unique in several respects and have therefore seemed well worthy of description. BIBLIOGRAPHY Anitscuxow, N. N. 1912 Studien iiber Nierengefiisse bei Angeborener Nier- endystopie. Virch. Arch. fiir path. Anat., Bd. 207, S. 213. Brown, M. 1894 Variations in the position and development of the kidneys. Journ, of Anat. and Physiol., vol. 28. Farquuarson, W. F. 1894 Case of left kidney, displaced and immovable. Journ. of Anat. and Physiol., vol. 28. Fetrx, W. 1912 The development of the urinogenital system. Keibel and Mall’s Human Embryology, vol.2, J.B. Lippincott Co., Philadelphia and London. Gérarp, G. 1905 Les anomalies congénitales du rein chez 'homme. Journ. de l’Anat. et de la Physiol., T. 16, p. 241 et 411. Jounson, C.E. 1914 Pelvie and horseshoe kidneys in the domestic cat. Anat. Anzeiger, Bd. 46, S. 69. Macauister, A. 1883 Multiple renal arteries. Journ. of Anat: and Physiol., vol. 17, p. 250. MeMorricn, J. P. A case of crossed dystopia of the kidneys with fusion. Journ. of Anat. and Physiol., vol. 32. MEttssinos, von K. 1911 Beckenniere mit persistierender Vena cardinalis dextra. Anat. Anzeiger, Bd. 39, S. 149. Morris, Henry 1885 Surgical diseases of the kidney. Cassell & Co., London. 1904 Surgical diseases of the kidney and ureter, including injuries, malformations and misplacements. vols. 1 and 2. Keener & Co., Chicago, U. 8S. A. Miéuiteruem, R. Ueber dei diagnostische und klinische Bedeutung der con- genitalen Nierendystopie, speciell der Beckenniere. Berlin. klin. Wochschr., 1902, S. 1130. Poutman, A. G, 1995 A note on the developmental relations of the kidney and ureter in human embryos. Johns Hopkins Hosp. Bull., vol. 16, no. 167, February, 1905. Tonxorr, W. 1903 Beitrag zu den Nierenanomalien, Intern, Monatschr. fir Anat. und Physiol., Bd. 20, 8. 449, Resumen por el autor, Eben James Carey. Colegio Médico Creighton, Omaha. Estudios sobre la dinimica de la histogénesis. La fuerza que motiva el crecimiento como estimulo dinidmico en la genésis de los tejidos esquelético y muscular. La regién activa dominante en el crecimiento del intestino es el tubo epitelial; la zona que crece menos activamente es el mesenquima que le rodea. En el colon terminal del cerdo el tubo epitelial crece en direccién caudo-cefilica. Las figuras mit6sicas siguen en su mayor parte la direccién de una hélice sinistrorsa. En embriones de cerdo de 10 a 25 mm. de longitud, el colon terminal crece relativamente con mas rapidez en diimetro que en longitud. Durante este periodo la ttinica interna de mits- culo liso esti en periodo de formacién. Cuando el embrién crece desde los 25 a los 45 mm. el colon terminal crece mas ripidamente en longitud que en anchura. Durante este periodo de alarga- miento intestinal rapido se inicia la capa externa de misculo liso. La correlacién del crecimiento tubular epitelial en longitud y anchura, con la génesis de las tinicas musculares lisas interna y externa, respectivamente, se considera bajo el aspecto de ‘‘ fuerza que motiva el crecimiento.”’ La regién de crecimiento acelerado en el miembro en vias de desarrollo es el nticleo esquelético cen- tral; la de crecimiento retardado es el mesenquima que le rodea, el cual se transforma ulteriormente en la musculatura y tejidos conectivos relacionados con ella. Estas dos zonas de crecimiento diferencial se influyen mutuamente, y esto es evidente objetiv- amente a causa de un cambio de movimiento y por una altera- cién de la forma externa y estructura interna de las células afectadas. El primer material 6seo del embrién se distribuye econémicamente en la periferia al principio, sobre la superficie convexa mas débil del fémur curvo. Después el hueso envuelve al centro de la diifisis y aparece en el lado c6ncavo del fémur carti- laginoso curvo. La correlacién entre el crecimiento esquelético acelerado y el desarrollo mesenquimiatico retardado se considera con referencia a la ‘‘fuerza que motiva el crecimiento diferencial.”’ Translation by José F. Nonideaz Cornell Medical College, New York AUTHOR'S ABSTRACT OF THIS PAPER ISSUED BY THE BIBLIOGRAPHIC SERVICE, JULY 26 STUDIES IN THE DYNAMICS OF HISTOGENESIS GROWTH MOTIVE FORCE AS A DYNAMIC STIMULUS TO THE GENESIS OF MUSCULAR AND SKELETAL TISSUES EBEN J. CAREY Department of Anatomy, Marquette University Medical School, Milwaukee, Wisconsin TWENTY FIGURES CONTENTS MRaaUrg GLC: LO TNS t rere arash aarti emie ey hestok Gaeeeispasiera eefayeieas ws efeis speyaGeseiern dow tes 199 Deteniironron crow tae motlye LONCe sponse cisco cree cre ce ered s cyecc nae eeetie cee 200 Early stages in the histogenesis and morphogenesis of the descending colon MERU RENT N SISSCr OLA) Lance nia eee te ete noe cite bis cilc th tocol bis cidihicletess 205 Spiral path of mitosis in epithelium of colon...................0..0020 000s 206 Growth motive force in intestinal development..........................4-- 210 HDeaniiion and) classification Of strains. <... aes ies ce. sae cece cnsceedens 211 Growth motive force in limb development................000000eccescecees 215 STUNTING TAT, eo ECS Og Sed oe REIS OREO 50 Ce TAC eee ee eae ee en 219 itera CaM UU COber rer eben evay ch spoht-o tages crs cyersssete ayes eie ey Siecean’® oe \ezavain ise ecesese rakoetee 224 INTRODUCTION The principle of unequal growth constantly confronts the embryologist in his investigations. The local thickenings and foldings of the central nervous system, the unequal growth of the cardiac septa, the elongated intestinal tract, are common instances exemplifying the principle that the body parts develop at different rates. This idea was recognized by Aristotle, but was not definitely formulated until 1774 from Wolff's convincing studies. In the latter’s work on intestinal development the principle of unequal growth was definitely established and elaborated considerably. In 1874, His compared the various layers of the chick embryo to plates and tubes of an elastic nature. From these he suggested that some of the principal organs are molded by local zones of unequal growth. Davenport (’96) resolves the changes in ques- 199 200 EBEN J. CAREY tion into movements of cells or cell aggregates, the latter being linear, superficial, or massive. He still further classifies each of these three divisions. These local zones of unequal growth and the movements of cells have been looked upon by Herbst (’94) and Dreisch (’94) as physiological responses to definite stimuli. His and Daven- port as well as Roux (’95) aim at something more than a mere. description of unequal growth and ontogenetic events. They made an attempt to give a mechanical causal explanation for these processes. The function and aetiology were considered side by side with structure. It is from the dynamic view-point that the present investiga- tion was pursued. It is desired to emphasize the fact that in zones of unequal or differential growth, in limb and intestinal development, that an interaction of forces takes place, resulting in a transference of energy, and that these forces are factors in histogenesis. This action and reaction and transference of energy is due to a definite entity, growth motive force, a term introduced by the writer. Growth motive force is any agency which tends to produce a trans- fer of kinetic energy, from an active to a less active group of cells, and of potential energy from a less active to an active group, in a cellular field of differential growth until equilibrium is established. The active and less active zones are in reference to the rate of cell division per millimeter of cross-section. This principle was deduced from a series of studies on osteogenesis and myogenesis begun in 1914. Previous reports of a part of this work have been presented to the Association of American Anatomists (Carey, 17, 18, 719). The understanding of the causes underlying tissue formation or differentiation of an unspecialized cell is the central difficulty for the student of development. The increase of cellular components, the transformation of these, and the perfection of form out of the relatively formless antecedents are phenomena which demand the closest analysis. Growth and division of the nucleus, however, are merely changes concomitant with the specialization which the cell undergoes. GROWTH MOTIVE FORCE 201 There are three theories regarding cellular differentiation: first, the ‘mosaic theory’ of Roux (’88), later modified by Wilson (04), Conklin (’05), Zeleny (’04), and Boveri (’04); second, the ‘organization theory’ of Whitman (’93) and more recently elabor- ated by Child (715) in the latter’s studies on metabolic gradients and individuality; third, the ‘homogeneity theory’ of Dreisch (’91-’93). Dreisch considers the peculiar organizing quality of protoplasm as due to the expression of a mysterious force wholly different from any in the inorganic world. At least in certain of the earliest stages, the primordial cell is modified during development by the environment. It is not independent in its development but is dependent upon an inter- action of developing parts before its external form and internal structure are perfected. Thisis the theory expressed by the terms, mutual interaction, correlation, interdependents, dependent dif- ferentiation or differentiation due to position. This theory is upheld by His (’74), Hertwig (’94), Fischel (’98), Von Baer (1828), Pfluger (’83), C. Schultze (1900), Hans Dreisch (94), Zoja (95), Whitman (’94), Child (99) and Thoma (’07) and to a limited extent by Roux. The latter investigator distinguished two periods in the development of the body parts: first, a period of self-differentiation in which the parts arise, grow, and differenti- ate of themselves; second, a period of functional form develop- ment in which the more complete formation of the parts is accomplished through the influence of stimuli. As to the first view, it has been convincingly proved that there are organ-forming stuffs in the cytoplasm. Wilson (’04) concluded from his studies that the cytoplasm of the primordial germ cell contains certain specific organ-forming stuffs which have a definite arrangement. These observations of Wilson have been confirmed by Conklin (’05), Zeleny (’04), Boveri (’04). The third theory regards differentiation as dependent upon either an extrinsic or an intrinsic factor. Differentiation so con- sidered is in the nature of a physiological response to a stimulus, The structure of the reacting as well as of the stimulating body, however, contributes to the quality of the effect. Specialization by this method is simply an ‘induction,’ according to Dreisch. 202 EBEN J. CAREY It is an effect produced upon the parts that are developing by other developing parts or by an extrinsic factor in the environ- ment. Three elements are consequently involved: first, the stimulus; second, the reception of the stimulus; third, the re- sponse. The first is some other organ or external agent; the sec- ond and third are functions of the organ in process of formation. Lack of evidence has been the chief obstacles to the acceptance of Dreish’s theory of induction. The term ‘induction’ implies an effect or change produced without contact. But, in respect to the primordium of the mus- cular and skeletal tissues, there is a definite syncytial continuity. Consequently, any effect produced by either tissue upon the other would be through ‘conduction’ and not through ‘induction.’ In this action, through conduction of the developing skeletal and muscular tissues upon each other, the factor of force is inher- ently involved. The primordial blastemal skeleton is under- going the most rapid growth, as a consequence of which a ten- sional elongating or stretching action is bound to be exerted upon the surrounding and less actively growing, continuous, syncytial mesenchyme. It is desired, therefore, to emphasize the follow- ing facts: First, that there is a force manifested by rapid skeletal growth. Second, that this force exerts a tensional or stretching action upon the surrounding mesenchyme, influencing the first steps of | myogenesis. Third, that the first differentiated muscles react upon the pri- mordial blastemal skeleton resulting in a definite series of changes. These are seen in the formation of the condensed cartilaginous skeleton and later, as the muscles become more developed and vigorous in physiological function, in the formation of the osseous skeleton. This action and reaction of forming parts results in the con- dition that at any period of development the degree of differ- entiation of the musculature and skeleton represents an equilib- rium established between opposing myogenic and skeletal forces. Mechanically, therefore, skeletal and the related muscular tis- GROWTH MOTIVE FORCE 203 sues are interdependent, one relying upon the other for its initial and continued differentiation. The foregoing applies to the skeleton and skeletal cross-stri- ated musculature. Concerning the smooth muscle of the intes- tine there is a similar interaction of differential forming parts. The epithelial lining of the alimentary tube is the most active region of growth. The growth in diameter in the early stages is due almost entirely to the rapid degree of mitosis of the epi- thelium and not to the surrounding mesenchyma forming the bulk of the wall. As a consequence the lumen rapidly increases in diameter, and it is this increase which causes primarily the diametrical growth of the intestine. It is readily apparent that the rapid distention of the lumen due to epithelial growth would cause a tension upon the relatively passive, contiguous, syncytial mesenchyme. This action would tend to draw out or stretch the mesenchymal cells in a concentric manner somewhat similar to the tension put upon the strained elastic fibers of a rubber balloon when distended with air, the pressure of epithelial growth being comparable to the air pressure. Once the encircling mesenchymal cells have formed a definite ring, the expanding lumen would meet a resistance to growth in diameter. The growth force, pursuing the lines of least resist- ance, would be directed in a longitudinal manner due to the shift- ing of the planes of mitosis from a longitudinal to a transverse direction. This shift is directly due to the external resistance of the first-formed ring of inner circular smooth muscle. At this point the term force is one that will stand close scrutiny and careful thought on the part of the embryologist. A force is one of a pair of equal, opposite, and simultaneous actions be- tween two bodies by which the state of their motions is altered or a change in form in the bodies themselves is effected. Pres- sure, attraction, repulsion, and traction are instances in point. Muscular sensation conveys an idea of force, while a spring bal- ance gives an absolute measure of it, and a beam balance only a relative measure. In accordance with Newton’s third law oi motion that action and reaction are equal, opposite, and simul- taneous, forces always occur in pairs. 204 EBEN J. CAREY Force is exerted in certain regions of the embryo by the genesis of a rapidly dividing group of cells upon a less active or relatively passive group of cells. In turn the relatively passive group react upon the former. This action and reaction is objectively evi- dent by a retardation or alteration of the rate of growth or by a change produced in the external form or internal structure of the cells involved. The most rapidly dividing group of cells in a differential grow- ing cellular field in syncytial continuity is subjected to a force tending to direct it in the path in which the resistance diminishes most rapidly, that is in the direction of a line of force. The most rapidly growing cells raise the kinetic energy of the field at the point of rapid growth above that of surrounding points, and hence a transference of energy takes place until equilibrium is established. There will be a transfer of kinetic energy from the growing to the passive group of cells resulting in an elonga- tion of the latter and a consequent storage of potential energy due to position. On the other hand, there will be a transference of potential energy from the elongated relatively passive group of cells to the moving or growing group which will tend to restrict or retard the motion or growth of the former. This motive force of genesis, growth, and differentiation continues until the differ- ence in energy disappears. These biological generalizations are analogous to electromotive force. If two metal spheres at different potentials be connected by a wire, a transfer of positive electrification will take place from the one of higher to the one of the lower potential, or a transfer of negative electrification from the one of lower to the one of higher potential, or of both, until the difference of potential dis- appears. The higher and lower electrical potentials are analogous to the continuous zones of rapidly dividing and less active group of cells, respectively. The term electromotive force is applied to any agency which tends to produce a transfer of electrification as exemplified above. Growth motive force consequently may be defined as any agency which tends to produce a transfer of kinetic and potential energy in a cellular field of differential growth. GROWTH MOTIVE FORCE 205 EARLY STAGES IN THE HISTOGENESIS AND MORPHOGENESIS OF THE DESCENDING COLON OF THE PIG (SUS SCROFA) The increase or decrease in size of certain parts of the intestine and the cellular transformations which occur are of fundamental importance. By analysis and careful description of the changes which occur in sequence and by subsequent synthesis of the data obtained, an interesting correlation in dynamics is thereby de- tected. Heretofore investigators of histogenesis have had in- dependent and isolated view-points in their work on intestinal development, no correlation of the developmental processes being attempted. The admirable descriptive observations on intestinal development by McGill (’07) and Johnson (711) fulfill the purpose of their respective authors, but lacked interpreta- tion and correlation of the facts observed. Their point of view was descriptive morphology, not dynamic. In an embryo 10 mm. in length the descending colon presents in cross-section an oblong oval. or pear-shaped appearance, the convexity of which is directed toward the interior of the abdomi- nal coelomic cavity. The tapering end is attached to the dorsal abdominal wall through the intermediation of the relatively long and thick dorsal mesentery. There are three main ele- ments which demand close attention (fig. 1). The first of these is the inner epithelial tube; the second, the outer peritoneal epi- thelium, and the third, the intermediate mesenchymal zone. The inner epithelial tube in cross-section is oval in shape con- taining a narrow oblong lumen with rounded ends. The lining cells of this tube form from two to three rows of nuclei. Mitosis is usually found in the superficial row of cells. At this stage mitotic activity is prominent in the epithelial cells. The basal row of cells rest upon a well-marked basement membrane. This basement membrane is directly contiguous to the inter- mediate mesenchymal zone. In this zone no clear-cut cell is found. The entire region is composed of protoplasm in syncytial continuity, embedded in which are found the nuclei. The nuclei are oval or round and present a very dense network of chromatin, especially well seen when stained with iron-hematoxylin. The membranes of the nuclei are decidedly distinct. The protoplasm 206 EBEN J. CAREY is granular, presenting an irregular network structure. Seat- tered in the mesenchymal region are seen isolated discrete vesi- cles. ‘These are especially congregated toward the dorsal mesen- teric attachment. The vascular vesicles are variable in size and shape and present various degrees of confluence. The thickness of the mesenchymal wall is nearly twice that of the diameter of the epithelial tube. It is to the rapid increase in diameter of the latter, due to rapid epithelial mitosis, that the increase in width of the intestine is to be ascribed. The mesen- chyme remains relatively passive, and as a consequence is put under great tension by the internal distention of the epithelial tube. Attention is especially directed to this difference in the rate of growth between the inner epithelial lining and the intermediate zone of mesenchymal cells. The continued differentiation of the intestine is pivoted upon this fact. Furthermore, the epithelial distention is not a uniform one., Mitosis takes place in a spiral manner from the anal toward the ileocecal valve. Consequently, . the rapid growth of the epithelial tube is a specific type from below upwards. The attention of the writer was directed to the fact, after plotting hundreds of intestinal epithelial mitotic figures, that these figures were usually confined to some definite region of the circumference of a single section. This region was found to change at different levels of the serial sections. By graphic reconstruction (sections 45 to 94) this plot was found to form the path of a definite spiral describing a dexiotropic rotation in one case; in nineteen others the path was a left-handed spiral. The spiral itself presented a head or apical region in which mitotic figures were found to be numerous and a tail or basal end in which there were fewer and fewer figures. The apical end of the spiral path is always directed toward the iliocecal valve and the basal end toward the rectum. Growth is therefore from below up- ward in a spiral course. One spiral growth is quickly followed by a second which rifles a path slightly lateral to its predecessor. This in turn is followed by a third, in a path still more lateral, and so on around the circumference. This intermittent rhythm GROWTH MOTIVE FORCE 207 of explosive spiral growth may be compared to that of the suc- cessive fire balls emitted by a roman candle in fireworks. The paths formed by this explosive spiral growth may be compared to those within the barrel of a Winchester rifle. Lining the outer peripheral portion of the mesenchyme is the peritoneal epithelium. In the 10-mm. embryo this is a single layer of oval or cuboidal cells. These are continuous from the dorsal mesentery and envelop the primitive colon proper. The cell walls of this layer are contiguous and give a beaded appearance to the peritoneal epithelium. Later in development this cellular layer becomes flattened and markedly elongated, the individ- ual cells becoming more and more attenuated and spindle-shaped. The beginning of this flattening or elongation of the peritoneal epithelium is seen in a 14-mm. embryo (fig. 2). This cross-sec- tion represents the corresponding region of the descending colon in the 10-mm. embryo described above (fig. 1). In addition to the elongation of the nuclei, the cytoplasm is drawn out into a fine membrane between the separated nuclei. At the same time that the peritoneal epithelium is elongated, the epithelial tube is seen to have grown double in size, whereas the mesenchyme has only increased one-half that of the former stage observed. The lumen of the epithelial tube is directed more transverse than vertical to the long axis of the gut. The lining cells appear to be overcrowding at the lower pole of the lumen due to rapid mitosis. This condition gives a stratified appearance to the epithelium. This rapid mitosis constantly causes an increase of free surface, and consequently the lumen rapidly dilates in width. Concomitant with the rapid increase in width of the epithelial tube, there is observed a change in shape and rearrangement of the surrounding mesenchymal cells. The nuclei and surround- ing granular protoplasm become elongated in a definite direction. Instead of the irregular arrangement: characterizing the oval nuclei and stellate cytoplasm before, there is now observed a definite tendency for the cells to form concentric layers. This tendency is more marked in the midzone of the mesenchyme be- tween the epithelial basement membrane and the outer simple epithelial peritoneum. In this midregion there is a condensation 208 EBEN J. CAREY more definite at the upper (fig. 2) than at the lower pole of the epithelial tube and greater in either polar region than on the lat- eral aspects of the tube. With a further absolute increase in diameter of the epithelial tube (fig. 3) over that of the intestinal wall, the smooth muscle elements become more elongated, flattened, and spindle-shaped, and the definitive inner circular smooth muscle layer becomes more clearly defined out of its former nebulous state (fig. 2). By actual measurement with the filar micrometer, the intestinal wall is seen to become thinner as the epithelial tube constantly increases in size. The embryo is now approximately 20 mm. in length, and during this period it is convincingly seen that the long axis of the elongated nuclei are arranged along the paths of concentric circles. The longitudinal granular fibrils are like- wise arranged in this concentric manner. With the constant increase in width of the epithelial tube there is a progressively greater and greater elongation of the muscle elements—nuclei and granular fibrils. These fibrils branch and anastomose with neighboring fibrils, and constantly maintain the original continuity of the protoplasmic syncytium. With the ever-increasing tension of the fibrils there is a progres- sive loss of water and increase in viscosity.!. Definite physico- chemical changes take place in the granular fibrils resulting in condensation and fusion of the granules into a continuous coarse irregular strand. Near the nuclei the swellings upon the strand are marked, but toward the poles of the nuclei the fibrils are more attenuated. ome As formerly reported by McGill, there is the same tendency in the development of the colonic,muscles to form coarse and fine myofibrils as detected in the oesophagus. These fibrils are of variable length and run through several neighboring cells in many cases. The coarse and fine granular fibrils are seen side by side. The coarser ones being primarily located at the periph- ery of the ill-defined spindle cell, whereas the finer granular myo- fibrils are located more internally and nearer to the nucleus. Between the fibrils more or less undifferentiated granular cyto- plasm persists. ! The chemical changes in myogenesis will be reported later with my colleague in biochemistry, Victor E. Levine. 2. GROWTH MOTIVE FORCE 209 In embryos, between 24 and 46 mm., the descending colon increases rapidly in length. Peripherad to the inner smooth- muscle coat there is found the beginning of elongation of cells similar to that described for the inner smooth-muscle coat. Sim- ilar changes in shape and arrangement of the components take place, however, in a longitudinal rather than in a transverse plane. At first this layer is more or less uniform throughout (figs. 3 and 4), but there is soon detected a greater proliferation of cells immediately underlying the dorsal mesentery. This aggregation of cells represents the inception of the longitudinal mesenteric taenia coli band of fibrils. This is definitely seen in figure 6. The initial genesis of the mesenteric taenia coli before the other bands appear is significant. If we remember that this location represents the outer curvature of a coiled tube in the process of rapid formation, it is readily seen that more definite tension of differential growth is exerted at this location. These bands are more definitely developed nearer the ileocecal valve. The dynamics involved will be considered later. The longitudinal muscle, however, is only slightly developed at 28 mm., and at 45 mm. is not as conspicuous as the myenteric Auerbach’s plexus. This plexus is located between the well- developed circular smooth-muscle coat and the attenuated outer longitudinal-muscle coat. The nerve plexus at these stages 10 to 46 mm. is composed of a continuous layer of groups of cells with crowded nuclei and many non-medullated fibers. The inner submucous plexus of Meissner is not as prominent as the outer one. It is similarly constructed, although it con- tains fewer and much smaller ganglia and the meshes of the plexus are much finer. The terminal nerve fibers were traced to the epithelium and between the epithelial cells at 46-mm. stage. The plexus first appears along the inner border of the inner circu- lar coat. The muscularis mucosa is not differentiated at 45 mm. The lymphatic channels, however, are abundant at 32 mm. along the line of the mesenteric attachment. Lymphatic nodules are not formed, on the other hand, in the submucosa until the 150-mm. stage is reached. 210 EBEN J. CAREY The lumen of the descending colon is patent throughout de- velopment; no sign of atresia is observed. Between the 10- and 14-mm. stages small vacuoles were found, but no diverticulae are seen. At 10 and 14 mm. the colon is round or slightly ellip- tical in shape, gradually enlarging toward the cloaca. The lu- men possess in the earliest stages a shape comparable to that of the entire tube. Between 53- and 46-mm. stages, however, lateral, evaginations are developed which give the lumen a cru- cial instead of a round or elliptical appearance. These evagina- tions push out at the lateral aspects where the circular muscle is least developed, along lines of least resistance. At the dorsal and ventral poles of the lumen the smooth muscle forms a thicker layer than on the lateral aspects. In addition, resistance is still further increased by the formation of the longitudinal mesen- teric taenia along the dorsal, attached margin of the descending colon. GROWTH MOTIVE FORCE IN INTESTINAL DEVELOPMENT In the inorganic world that which produces motion or pressure is considered as due to a force. This entity has already been defined. One result of its action on an elastic body, namely, a strain, should now be considered. This is imperative, for if mechanical forces are at work on organic matter they tend to produce similar results as those acting upon inert matter. Too frequently the term self-differentiation is applied to alteration of form and internal structure of developing cells without searching the immediate environment of the specializing cells or syneytium to ascertain whether or not these changes are attributable to forces outside of the differentiating zone: This applies particu- larly to the differentiation of bone and muscle tissue. If a cell changes in form successively through the spherical, ellipsoid, and spindle stages it undergoes a strain. A strain is usually due to an external force which elicits internal reacting stresses in the body acted upon. Cytological differentiation is frequently a manifestation of these internal reacting stresses. It will prove to be an illuminating study to search for the cel- lular forces outside of the immediate differentiating zone under GROWTH MOTIVE FORCE 211 observation. This search necessitates lower magnifications in order to enlarge our field of view. Heretofore cytological dif- ferentiation has been studied per se with magnifications of 1000 to 2000 diameters which considerably reduces our range of view. The higher magnifications are profitable in revealing cytological detail, but the interpretation of the process is lost unless in con- junction with the higher, intermediate magnifications are used. By employing all possible magnifications of the microscope in connection with naked-eye studies we are less likely to lose the forest for the trees. Such a method is likely to reveal the inter- action of related developing parts. Before applying this method it will be of advantage to consider briefly the different types of strain with which we are concerned. DEFINITION AND CLASSIFICATION OF STRAINS Elastic bodies are those in which a change takes place in the relative positions of their parts in contradistinction to rigid bodies in which no change occurs in the relative positions of their parts. Elastic bodies may suffer changes in their size or shape. Any definite alteration in the form or dimensions of an elastic body is called a strain. This fact may be brought out in the following illustration: A rod which becomes longer or shorter is strained. Water when compressed is strained. A stone, beam, or mass of metal in a building or in a piece of framework, if condensed or dilated in any direction or bent, twisted or distorted in any way is said to experience a strain. A ship is said to ‘strain’ if, in launching or when working in a heavy sea, its different parts experience rela- tive motions. The simplest strain is a linear one. The stretching of an elas- tic cord is an example. This strain is called homogeneous when every portion of the cord has its length changed in the same ratio, so that the ratio of the initial to the final length of each part is the same as this ratio for the whole. The ratio of the final to the initial length is called the ratio of the strain; it repre- sents evidently the quantity by which the initial length must be multiplied to obtain the final length. The elongation is the 212 EBEN J. CAREY ratio of the change in the length to the initial length. A nega- tive elongation, or shortening, is called a compression. A posi- tive elongation, or lengthening, is called a tension. When all lines in a body parallel to a certain direction are changed in the same ratio, and no lines perpendicular to these are changed either in length or direction, the body suffers a strain of simple elongation. If, however, a second set of lines at right angles to these also suffer such a change, then there is elongation in two perpendicular directions; and if these lines are all in the same plane, the strain is a surface strain. A square elastic sheet, if the longation be e in a direction parallel to one edge, and e’ parallel to another, will be converted by the strain into a rec- tangular sheet, the sides of which are proportional to the strain- ratios. Evidently two equal and parallel lines drawn on the square will remain equal and parallel after the change in form; and the strain will be homogeneous. If the elastic sheet be cir- cular, the strain will change the circle into an ellipse, the two perpendicular directions which remain perpendicular after the strain becoming the axis of the ellipse. If these lines remain parallel to their original directions, the elongations take place’ along them and the strain is called a pure strain. If not, the strain is compounded of a pure strain and a rotation. As seen above, the principal axis of a strain is the principal axis of the ellipse into which the strain converts a circle. If the increase of length along one such principal axis is equal to the decrease of length along the other principal axis, the strain under these circumstances is called a shear. Evidently in a shear the area of the plane itself remains unaltered. Any plane figure may be converted into a strained figure; that is, the shearmg strain may be produced simply by fixing one of its sides, and moving all lines parallel to this fixed side in their own directions, through spaces which are proportional distances from this fixed line. The amount of this sliding motion which takes place between lines which are unit distance apart is called the amount of shear. When a solid body undergoes a strain, a change may take place in its dimensions in one or more of three perpendicular directions. If the strain is such that all parallel lines within it are altered in “ v. GROWTH MOTIVE FORCE 213 length in the same ratio, the strain is called a uniform or ho- mogeneous strain, as previously pointed out. Thus, for ex- ample, a sphere when subjected to strain is converted into an ellipsoid, a solid every plane action of which is an ellipse. This ellipsoid is called a strain-ellipsoid. In any homogeneous strain of a solid body there are three directions at right angles to one another, which remain perpendicular after the strain. These directions are those of the three principal axes of the strain- ellipsoid. Along one of these directions the elongation is greater and along another less than along any other direction in the body. Along the remaining one the elongation is intermediate. The principal axis of a strain is the principal axis of the ellipsoid into which it converts a sphere. The principal elongations of a strain are the elongations in the direction of its principal axis. Ac- cording to Thomson and Tait, ‘‘Any strain may be viewed as compounded of a uniform dilatation in all directions, superim- posed on a simple elongation in the direction of one principal axes, superimposed on a simple shear in the plane of the other two principal axes.” With this brief account of the nature of strain we may now pass on to the consideration of the effects of differential growth in intestinal development. The most rapidly growing part of the intestine is the epithelial tube (figs. 1 to 6). In 10- to 23-mm. embryos the descending colon grows relatively more rapid in diameter than in length. The increase in diameter is due primarily to the rapid growth of the entodermal epithelial tube and only partially to its surround- ing mesenchymal cloak. The latter is relatively passive in growth with respect to the former. It is during this early in- crease in diameter that the inner smooth-muscle coat is in the process of formation. The mesenchymal cells are drawn out gradually in a definite series of concentric rings. These rings appear not unlike those of the planet Saturn and the annular nebula in Lyra. A definite centripetal force is active in the rapid, spiral growth of the intestinal epithelial tube. The surrounding mesenchymal cells are thrown into a definite series of concentric rings accord- THE ANATOMICAL RECORD, VOL. 19, No. 4 214 EBEN J. CAREY ing to their various densities. Those possessing the greatest den- sity joining the outer ring in the tangential path of the force, whereas the inner rings will be composed of bodies forming a gradient of decreasing densities. The cells forming the outer ring will be most elongated. Their water content decreases and viscosity increases. As this concentric initial smooth-muscle layer becomes differ- entiated it tends to restrict the diametrical growth of the epi- thelial tube. The epithelial mitotic figures under this restric- tion shift their planes of division from a right angle to a parallel position with the smooth-muscle cells. This shifting results in an elongation of the intestine. In embryos 25 to 40 mm. in length, the elongation of the de- scending colon is more rapid in growth than that of the diameter. It is during this period that the outer longitudinal muscular coat is in the process of formation. The rapid growth of the epi- thelial tube in length tends to elongate the peripheral undiffer- entiated mesenchymal cells which were not directly involved in the formation of the inner smooth muscular coat. The differentiation of the outer longitudinal muscle coat there- fore coincides, in time, with the rapid growth in length of the intestinal epithelium. The inner smooth-muscle coat, on the other hand, is formed during the period of the rapid growth of the intestinal epithelial tube in diameter. In this study, the initial zone of rapid growth is found in the epithelial cells. Kinetic energy is transferred from within to the surrounding splanchnic mesenchyme by rapid spiral ex- pansion of the entodermal epithelial tube. The less actively growing cells of the peripheral region of the intestinal wall are elongated. Later the potential energy of the elongated cells is transferred to those of the epithelium, resulting in a retardation of the growth in diameter. Immediately following this retardation of diametrical growth, the period of rapid growth of the intestine in length takes place. In this development, therefore, the factor of growth motive force, as a cause in the transference of kinetic and potential energy, is definitely detected. GROWTH MOTIVE FORCE 215 Once the formation of the inner circular muscular rings is fairly established, a resistance to growth in width is encountered by the cells surrounding the rapidly dilating lumen. These cells then grow primarily along the path of least resistance in a longitudinal manner. At this stage the lontitudinal muscle cell, spherical in shape in figure 15, is elongated to a spindle-shape structure in figure 16. In conclusion an interesting correlation in the development of the oesophagus in the human may be cited. This correlation was detected in the work of Jackson (’09) and in that of Keibel and Elze (’08). The former investigator studied the develop- mental topography of the oesophagus, the two latter the histo- genesis of the oesophagus. Jackson states that the descent of the stomach is accompanied by a great elongation of the oesoph- agus. In a 9.4-mm. specimen the oesophagus measures 1.8 mm.; at this proportion, it should measure 4.3 mm. in an embryo 22.8 mm., but its actual length is found to be 8mm. ‘The year previously Keibel and Elze reported that the oesophagus in 12.5-mm. embryos show a circular but no longitudinal muscle layer; in 17-mm. embryos they find a circular layer with the longitudinal layer faintly indicated. The histogenesis of the outer longitudinal layer of the oesophagus as studied by Keibel and Elze coincides in time with the rapid elongation of the oesophagus, due to the descent of the stomach, as recorded by Jackson. GROWTH MOTIVE FORCE IN LIMB DEVELOPMENT The detailed description of the direct observations made on bone and skeletal muscular development will be reserved for a subsequent communication. When the embryo is approximately 10 mm. in length, the first indication of the limb is a bud filled with a densely packed mass of uniform mesenchymal cells. Eventually, when the embryo is 14 mm. in length, a condensation of nuclei is detected in the center of the bud. This central condensation represents the pri- mordial blastemal skeleton. It is the most rapidly moving or growing part of the limb. This is evident by the greater number 216 EBEN J. CAREY of mitotic figures and by the relative scarcity of cytoplasm and consequent closely compact nuclei. As the central core of the limb pushes forth more rapidly than that of the peripheral con- tinuous mesenchymal cells, there is a tendency for the latter to be pulled out, stretched, or elongated by the former. The trac- tion force of the rapidly growing appendicular core exerted upon the surrounding mesenchyme is the internal stimulus of a corre- lated part, resulting in the elongation of the nuclei-of the pre- muscular mass in the direction of the blastemal skeletal growth. From this direct observation that the cells of the premuscular mass are elongated in the direction of skeletal growth, we detect the objective evidence of the transference of kinetic energy from the zone of rapid growth to that of the relatively passive one. As differential growth continues and the growth motive force becomes more and more manifest, there is also detected a draw- ing out or stretching of the peripheral syncytial cytoplasm in the direction of the skeletal growth. This is first shown by the ap- pearance of relatively parallel rows of discrete, isolated granules which represent differences in density of the cytoplasm due to the traction to which it is subjected. This is comparable to the tendency of a viscid substance, like egg albumen, to collect in droplets if placed between two glass slides when these are sep- arated by a shearing force. When the viscosity of the cytoplasm increases, on the other hand, with increased structural differentiation, these granules fuse and form a continuous condensed cytoplasmic strand known as the myofibril. At first this myofibril is coarse, but as the trac- tion of skeletal growth continues it gives rise to numerous fibrils finer in texture. Thus, there is a direct proportional increase of the cytoplasmic components with continued skeletal growth. The formation of the embryonic skeletal muscles represents a definite reaction to the growth of the skeleton. These muscles tend to restrict the growth of the skeleton in length. This is manifested by an increasing condensation of the skeletal core. This condensation is seen in the transition of the densely nu- cleated syncytial blastemal skeleton into the cartilaginous skele- ton. The greater stability of the latter counteracts the deforma- GROWTH MOTIVE FORCE 217 tion that would naturally occur in the former as the primitive muscles begin to contract. On the other hand, with increased skeletal condensation there is presented a more rigid base, and this in turn acts as a stimulus to more definite muscular dif- ferentiation. This is detected by direct observation in the split- ting up of the uniform premuscular masses into its individual muscular components. Muscular forces become consequently more definitely applied and the definitive parts of the skeleton become more clearly outlined. As the growth motive force of differential growth continues, the musculature becomes too vigorous for the cartilaginous base. The blastemal skeleton, as noted above, is supplanted by the cartilaginous one; there is now found another replacement of the cartilaginous by the osseous skeleton. The changes which occur in a cartilaginous component of the skeleton, as the femur, in the formation of the more stable bony base, together with the concomitant muscular changes are as follows: 1. There is a bending of the cartilaginous femur with the con- vexity of the bow directed toward the M. quadriceps extensor. This deformation is incident to the contractility of the thigh musculature and the inception of the adduction action in rotation of the hind limb. This femoral strain is due to active and pas- sive muscular stresses. 2. A strain fibrosis is detected on the weaker convex tensile aspect of the curved femur resulting in the histogenesis of the primary perichondrium which subsequently encircles the shaft. 3. Concomitant with increased muscular differentiation and subsequent activity there is a progressive dehydration, increase of viscosity, and increase of total acidity (table 1). 4. Inception of necrobiosis of the cartilage cells is seen immedi- ately underlying the initial location of formation of the primary encapsulating perichondrium. This necrotic change is due to the diminished blood supply caused by the restricting action of the forming perichondrium. By injection and serial sectioning methods it is revealed that all capillaries and incipient discrete vesicles, precursors of capillaries, are peripherad to the primary perichondrium. 218 EBEN J. CAREY 5. The vesiculated cartilage cells are arranged along definite curved tensile and compressile stress lines. Previous to the bending of the femur these cells are irregularly related to one another. ; 6. Hyalinization of cartilaginous matrix in the central zone of the curved femur is next observed. TABLE 1 TITRATION OF 1 GRAM OF EMBRYONIC PREMUSCLE EN ’ wage ett fh ta) A AND MUSCULAR TISSUE TO ef NaOH mm. cc. 10 2.5 12 3.5 13 3.5 14 4.9 16 9.0 19 11.0 20 13.0 22 14.0 23 13.5 24 13.8 25 17.0 27 23.0 30 21.5 32 24.0 35 27.8 37 31.0 39 32.1 40 31.5 42 34.0. 45 35.5 7. Calcification then takes place in the hyalinized matrix. These intergrading steps in the condensation of the matrix is incident to increased muscular growth and functional activity and to the passive resistance of the musculature to skeletal elongation. 8. A subperiosteal osteogenetic and constricting cellular zone is begun immediately underlying the initial zone of fibrosis on the summit of the convexity of the curved femoral rod. This osteoblastic constriction quickly encircles the shaft. This is the — GROWTH MOTIVE FORCE 219 beginning of a consecutive series of bony deposition. This bony deposit is due to two factors: first, the stimulus of the functionally active thigh muscles and, second, the stimulus of the restriction to growth at the ends of the rapidly elongating femoral rod due to passive muscular resistance. These two factors tend to stimulate the formation of the osseous skeleton in replacing the calcified cartilaginous skeleton. From the foregoing brief account it is desired to emphasize the following: That there is a direct transference of kinetic energy from the more rapidly growing skeleton to the less actively growing prim- itive musculature and a reactive transference of potential energy from the latter to the former, tending to a condition of equili- bration. With the inception of functional muscular activity there is a direct transference of kinetic energy from this tissue to the growing skeleton tending to retard or alter its motion or growth. The resistance passively manifested by the muscles is an addi- tional factor tending to inhibit skeletal growth. This fact is also noted by Holl, Schomberg, and especially by Bardeen. In this case there is a transfer of potential energy due to position from the muscles to the skeleton. This active and passive play of the muscles on the cartilaginous base resulting in a condensa- tion of a more stable framework and the consequent more defi- nite effect of the latter on the former is due to a direct transfer- ence of energy by conduction. This transference of energy is of fundamental importance and is produced by the motive force of differential growth. SUMMARY Intestinal development 1. The region of most active mitosis, per mm. of cross-section, in the intestine is the entodermal epithelial tube. The mitotic figures primarily follow a path of a left-handed helix. 2. The region of least active or relatively passive growth per mm. cross-section is the mesenchyme, derived from the splanch- nic mesoderm, surrounding the epithelial tube. 220 EBEN J. CAREY 3. The rapid expansion due to epithelial growth in a rotating spiral manner of the intestinal lumen is greater than the activity manifest in the surroundingey mesenchyme. This causes a pres- sure in the latter resulting in a flattening and an elongation of the mesenchymal cells. The suecessive changes in shape of these cells through the spherical, ellipsoidal, and spindle cellular phases are seen. The mesenchymal wall decreases in thickness, due to tension caused by epithelial tubular dilation. 4. The rotating spiral growth of the epithelial cells causes the formation of a series of mesenchymal cellular and fibrillar con- centric rings due to the centripetal force of the former. . 5. The inner circular smooth-muscle cells are differentiated in the outer more condensed margins of the ring. At these points the developing tensional stresses are greater than within the ring. 6. The tensional stresses to which the elongated strained mes- enchymal cells are subjected appear to be a dynamic stimulus to smooth-muscle differentiation. 7. The inner circular smooth-muscle coat is the first one differ- entiated and is incident to the rapid growth of the epithelial tube in diameter. The kinetic energy of epithelial growth is transferred to the surrounding inner developing annular muscle. The latter soon tends to restrict the growth of the epithelial tube in diameter. The tube, pursuing the lines of least resistance, grows in length. During the period of rapid growth in length the outer longitudinal muscle coat is in the process of formation. 8. There is thus a definite interaction in intestinal develop- ment. We find evidence of a transference of kinetic energy from the zone of rapid growth of the epithelial tube to the less active mesenchymal wall resulting in the storage of potential energy due to position in the latter. Subsequently a transfer of resisting potential energy from the elongated mesenchymal cells to the rapidly growing cells of the epithelial tube. This tends to retard growth in diameter and to accelerate growth in length of the epithelial tube. 9. The developing musculature loses water. It increases in viscosity and total titratable acidity. GROWTH MOTIVE FORCE 221 10. The increase in size of the granules in the mesenchyme is incident to the increase in viscosity. These granules are ar- ranged in rows parallel to the long &xis of the elongated nuclei. The same forces at play in nuclear elongation are involved in the formation of the rows of granular fibrils. The formation of the coarse continuous myofibrils occurs at a period when the vis- cosity and dehydration increases rapidly. 11. The following factors are intimately involved, therefore, in myogenesis: a. Tensional stresses elicited by a force external to the differ- entiating myoblasts. b. Loss of water. c. Increase of viscosity. d. Increase of total titratable acidity. ‘Limb development 1. The region of most active mitosis, per mm. cross-section in the limb is the skeletal core. 2. The region of least active or relatively passive mitosis, per mm. cross-section, is the surrounding continuous syncytial mesenchyme. 3. Potential energy is transferred from the rapidly growing blastemal skeleton resulting in an elongation or a homogeneous strain of the surrounding continuous syncytial mesenchyme. 4. With the rapid progressive extension of the blastemal skele- ton more and more strain is put upon the elongating mesenchy- mal cells. The latter reacts upon the former continuously. There is a progressive condensation of the skeleton through the embryonal to the alveolar or cellular hyaline cartilage stages. This gradual condensation is detected during a period when the premuscular masses are being split into the individual muscles between 14- and 18-mm. stages. 5. Between 19 and 21 mm. the muscles become functionally active. Limb rotation is begun during this period. 6. The longitudinal continuous myofibrils are differentiated between 14- and 18-mm. stages. 222 EBEN J. CAREY As the growth motive force of differential growth continues, the musculature becomes too vigorous for the cartilaginous base. The blastemal skeleton, as noted above, is supplanted by the cartilaginous one; subsequently another iar of the ear- tilaginous by the osseous skeleton occurs. 8. There is a direct transference of kinetic energy from the more rapidly growing skeleton to the less actively growing primi- tive musculature and a reactive transference of potential energy from the latter to the former, tending to a condition of equilibra- tion. With the inception of functional muscular aetivity there is a direct transference of kinetic energy from this tissue to the growing skeleton tending to retard or alter its motion or growth. The resistance passively manifested by the muscles is an addi- tional factor tending to inhibit skeletal elongation. This fact is also noted by Holl, Schomberg, and especially by Bardeen. In this case there is a transfer of potential energy due to position from the muscles to the skeleton. This active and passive play of the muscles on the cartilaginous base resulting in a condensa- tion of astable frame work and the consequently increased definite effect of the latter on the former is due to a direct transference of energy by conduction. This transference of energy is of funda- mental importance and is produced by the motive force of dif- ferential growth. General deductions from the study of myogenesis Contractility is a fundamental property of primordial proto- plasm. The protozoan, amoeba, possesses the property of con- tractility in all possible directions. The function of contraction in one definitive direction characterizes muscle tissue from that of undifferentiated and isolated organized particles of primordial protoplasm. What initiates the progressive series of physico- chemical changes in primordial protoplasm resulting in an altera- tion of its attribute from non-specificity to specificity of direction of contractility? This question is answered as follows: The primordial protoplasm before differentiating into muscle tissue, must be subjected to a certain minimal homogeneous and GROWTH MOTIVE FORCE DS ellipsoidal strain. This strain is objectively evident by an al- teration of the form of the spherical nuclei into the ellipsoidal and spindle conditions and by an elongation of the granular cytoplasm into parallel granular and continuous fibrillae. The fibrillae are arranged along lines of internal and reacting tensional stresses. The ends of the primordial protoplasm, in tension, must be attached to supports of which one, at least, is mobile. The tensional stresses are reactions to simultaneous forces extrin- sic to the zone of myogenesis. _ The external forces cause a pro- gressive divergence or separation of the mobile supports to which the primordial protoplasm is attached. Therefore, muscle tis- sue is not self-differentiating, but is dependent upon an exter- nal dynamic stimulus. As regards smooth and skeletal muscles, this stimulus is the motive force of differential growth. Growth motive force is any agency which tends to produce a transfer of kinetic energy, from an active to a less active group of cells, and of potential energy from a less active to an active group, in a cellular field of differential growth until equilibrium is established. Whether or not the end-product in muscular formation will be of the smooth or cross-striated type depends upon the intensity of the stimulus of tensional stresses to which the mesenchyme is subjected. The genesis and maintenance of muscle tissue rep- resents a resultant or equilibration of converging factors which are active and formative during development. One of these factors is the tensional stresses to which the mesenchyme is sub- jected by a force extrinsic to the differentiating zone. In sub- sequent involution or degeneration of muscular tissue, during the prenatal or postnatal periods, this equilibrium is upset by altering or destroying the tensional reacting stress. It is a pleasure to record my grateful acknowledgment to my former chief, Dr. H. Von W. Schulte, of Creighton University, for his encouragement, helpful interest and suggestions, and for the opportunities he has extended to me in order to complete this part of my study on bone and muscle development. 224 EBEN J. CAREY I wish also to express my indebtedness to Mr. M. W. Murphy, manager of the Cudahy Packing Company; Dr. O. A. Edwards, private veterinarian and supervisor of the Swift Packing Com- pany, and to Mr. L. A. Orchard, superintendent of the Armour Packing Company, South Side, Omaha, for their courtesies and generous permission in allowing me to obtain unlimited numbers of pig embryos for this study. For the beautiful clear-cut illustrations, my thanks are due to Madame Helen Ziska. : Finally, for the ever ready help in completing this work, I owe my lasting gratitude to my wife. LITERATURE CITED AristoTLe 1837 De Generatione Animalium, ed. Bakker; De Faranue Ani- malium, ed. Bakker. 1877 De Anima, ed. Trendelenburg, Berlin. Barpeen, Cuartes R. 1910 Morphogenesis of the skeletal system. Keibel and Mall, Human Embryology, vol. 2, p. 378. 1905 Studies of the development of the human skeleton. Am. Jour. Anat., vol. 4, pp. 265-305. BARDEEN AND Lewis 1901 Development of the back, body wall, and limbs inman. Am. Jour. Anat., vol. 1. BarpEEN, Cuartes R., ano Lewis, W. H. 1901 Development of the limbs, body-wall and back in man. Am. Jour. Anat., vol. 1. Born, G. 1885 Ueber den Einfluss der Schwere auf das Froschei. Arch. Mikr. Anat., Bd. 24. Boverr, T. 1904 Protoplasmadifferenzierung als auslésender Faktor fir Kernverschiedenheit. S.-B. phys.-med. Gas., Wiirzburg. Ergeb- nisse iiber die Konstitution der chromatischen Substanz des Zellkerns. Jena. Carey, Espen J. 1917 Preliminary report on the normal unequal growth and degeneration in the early ossification centers in the diaphyses of femora of the pig. Anat. Rec., vol. 11, no. 6. 1918 Early stages in the development of the pig with reference to the influence of muscular activity upon its ossification. Anat. Rec., vol. 14, no. 1. 1919 On the interaction of the primary femoral ossification, thigh muscular differentiation, knee and hip-joint formation; during the period of rotation of the hind limb of the pig (Sus scrofa). Anat. Rec., vol. 16, no. 3. 1919 Teratological studies. Anat. Rec., vol. 16, no. 2 Cuitp, Cuartes Mannine 1915 Individuality in organisms. The University of Chicago Press, Chicago, II]. GROWTH MOTIVE FORCE 225 Conxurn, E. G. 1905 Mosaic development in Ascidian eggs. Jour. Exp. Zool., vol. 2. Dretisu, H. 1894 Analytische Theorie der organische Entwicklung. Leipzig. Dretsu, H., anp Morean, T. H. 1896 Zur Analysis der ersten Entwicklungs stadien des ctenophorenesis. Arch. Ent. Mech., Bd. 2. Davenport, C. B. 1896 Studies in morphogenesis: IV. A preliminary cata- logue of the processes concerned in ontogeny. Bull. Harvard Mu- seum xxvii. Fiscuent, A. 1895 Zur Entwicklung der vertralen Rumpf u. Extremititen- muskulatur bei Véglen and Siugetieren. Morph. Jahrbuch, Bd. 23. Fiscuet, H. 1898 Experimentelle Untersuchungen am Ctenophorenei. I. Arch. Ent. Mech. VI, II, III, IV ibid. VII. Furamura, S. 1906 Ueber: die Entwicklung der Facialismuckulatur des Menschen mit 27 Texabbildungen. Anat. Hefte, Bd. 30. Harrison, R. G. 1904 An experimental study of the relation of the nervous system to the developing musculature in the embryo of the frog. Am. Jour. Anat., vol. 3. Herest, C. 1894-1895 Ueber die Bedeutung der Reizphysiologie fiir die caus- ale Auffassung von Vorgiingen in der thierischen Ontogenese. Biol. Centralbl., Bd. 14, 15. Hertwic, O. 1894 Zeit und Streitfragen der Biologie. ‘Jena. His, W. 1874 Unser Kérperform und das physiologische Problem ihrer En- stehung. Leipzig. Hou, M. 1891 Uber die Entwicklung der Stellung der Gliedmassen des Meschen. Setzungsb. d. k. Akad. d. Wisi. Wein Math. Naturw. Klasse, Bd. 100, eT., S. 12. Wien. Jackson, C. M. 1908 An unusual duodenal diverticulum. Jour. of Anat. and Phys., vol. 42, pp. 219-220. 1909 On the developmental topography of the thoracic and abdom- inal viscera. Anat. Rec., vol. 3, pp. 361-396. JENKINSON, J. W. 1909 Experimental embryology. Oxford. Jounson, F. P. 1910 The development of the mucous membrane of the esopha- gus, stomach, and small intestine in the human embryo. Am. Jour. Anat., vol. 10, pp. 521-561 Kerse, F., anp Evze, C. 1908 Normentafeln zur Entwicklungs geschichte der Wirbeltiere. Heft 8, 8. 1-314. Jena. Kor.irker 1889 Handbuch der Gewebelehre des Menschen. S. 253. Lewis, W. H. 1901 The development of the arm in man. Am. Jour. Anat., vol. 1. 1901 Observations on the pectoralis major muscle in man. Johns Hopkins Hosp. Bull., vol. 12. 1903 Wandering pigmented cells arising from the epithelium of the optic cup, with observations on the origin of the m. sphincter pupillae in the chick. Am. Jour. Anat., vol. 2. 1904 Experimental studies on the development of the eye in Am- phibia. I. On the origin of the lens. Am. Jour. Anat., vol. 3. 1905 II. On the origin of the cornea. Jour. Exp. Zool., vol. 2. 226 EBEN J. CAREY Lewis, F. T., anp Tuyne, F. W. 1908 The regular occurrence of intestinal diverticula in embryos of the pig, rabbit, and man. Am. Jour. Anat., vol. 7, pp. 505-519. Loes, J. 1892 Untersuchungen zur physiologischen Morphologie der Thiere. MacCauium, J. B. 1898 On the histogenesis of the striated muscle-fibre and the growth of the human sartorius muscle. Johns Hopkins Hosp. Bull. Maui, F. P. 1897 Ueber die Entwicklung des menschlichen Darmes und seiner Lage beim Erwachsenen. Arch. fiir Anat. und Entw., Supple- mentband, 8S. 403-434. 1898 Development of the ventral abdominal walls in man. Jour. Morph., vol. 14. 1898 Development of the human intestine and its position in the adult. Bull of the Johns Hopkins Hosp., vol. 9, pp. 197-208. 1899 Supplementary note on the development of the human intes- tine. Anat. Anz., Bd. 16. 1901 On the development of the human diaphragm. Johns Hopkins Hospital Bulletin, vol. 12, and Proceedings of Amer. Assoc. Anatom., vol. 5, Washington. McGitz, Carotine 1907 The histogeneis of smooth muscle in the alimentary canal and respiratory tract of the pig. Internat. Monatschrift. Anat. u. Phys., Bd. 24. 1910 The early histogenesis of striated muscle in the oesophagus of the pig and dogfish. Anat. Rec., vol. 4, pp. 23447. Meek, A. 1898 Preliminary note on the post-embryonal history of striped muscle-fibres in Mammalia. Anat. Anz., Bd. 14 and 15. 1899 On the post-embryonal history of voluntary muscles in mam- mals. Journ. of Anat. and Physiol., London, vol. 33, pp. 546-608. Moran, T. H. 1902 The dispensability of gravity in the development of the toad’s egg. Anat. Anz., Bd. 21. Priitcer, E. 1883 Ueber den Einfluss der Schwerkraft auf die Teilung der Zellen. Pfluger’s Arch., Bd. 31-33. Porowsky, J. 1899 Zur Entwickelungsgeschichte der Dammuskulatur beim Menschen, 2 Taf. Anat. Hefte, Bd. 12. Preyer, W. 1885 Spezielle Physiologie des Embryo. Leipzig. Revter 1896 Ueber die Entwickelung der Kaumuskulatur bein Schwein. Anat. Hefte, Bd. 7. 1897 Ueber die Entwickelung der Augenmuskeln beim Schwein. Anat. Hefte, Bd. 9. Roux, W. 1881 Der Kampfder Theileim Organismus. Leipzig. 1893 Ueber Mosai Karbeit und neuere Entwicklungshypothesen. Anat. Hefte. Russett, E. 8. 1917 Form and function. New York. Scuompurc, H. 1900 Untersuchungen der Entwicklung der Muskeln und Knochen des menschlichen Fusses. Dissertation. Géttingen. Scnuttze, O. 1900 Ueber die Nothwendigkeit der freien Entwicklung des Embryo. Arch. Mikr. Anat., Bd. 4. Spemann, H. 1903 Ueber Linsenbildung bei defekter Augenblase. Anat. Anz., Bd. 23. = ire GROWTH MOTIVE FORCE PPA Toma, R. 1907 Synostosis suturae sagittalis cranii. Archiv fiir patho- logische Anatomie und Physiologie, Band 188. von Barr, Kart Ernst 1828 Ueber Entwicklungsgeschichte der Tiere, Beo- bachtung und Reflexion. K6nigsberg. Wetts, H. Ginron 1918 Chemical pathology. Witson, E. B. 1896 Cleavage and mosaic work. Appendix to Crampton’s paper on Illyandssa. Arch. Ent. Mech., Bd. 3. 1904 Experimental studies on germinal localization. I. The germ regions in the egg of Dentalium. Jour. Exp. Zool., vol. 1. 1904 Experimental studies on germinal localization. II. Experi- ments on the cleavage mosaic in patella and dentalium. Jour. Exp. Zool., vol. 1. 1904 Experimental studies on germinal localization, I, II. Jour. Exp. Zool., vol. 1. Wotrr, C. F. 1759 Theoria generationis. Wiirzburg. 1768 De formatione intestinorium. Wiirzburg. ZELENY, C. 1904 Experiments on the localization of developmental factors in the Nemertine egg. Jour. Exp. Zool., vol. 1. Zora, R. 1895-96 Sullo sviluppo die blastomeri isolati dalle nova di aleune meduse. Arch. Ent. Mech., Bd. 1, 2. PLATE 1 EXPLANATION OF FIGURES The tissue was fixed in Zenkers solution; the sections were cut at Su and stained with iron-hematoxylin and picric-acid-fuchsin. The drawings were made with the aid of a Spencer camera lucida. Figures 1 to 6 are magnified 100 diameters. 1 Transverse section of descending colon 10-mm. pig 2 Transverse section of descending colon 14-mm. pig 3 Transverse section of descending colon 20-mm. pig 4 Transverse section of descending colon 25-mm. pig 5 Transverse section of descending colon 3l-mm. pig 6 Transverse section of descending colon 46-mm. pig ABBREVIATIONS dm., dorsal mesentery sp., Meissners plexus (submucous) em., inner circular smooth-muscle ap., Auerbach’s plexus (intermus- layer cular) Im., outer longitudinal smooth-muscle — sm., serosa layer subm., submucosa mt., mesenteric taenia muscle band p.m., primordial mucosae cells N. B.—Note especially rapid increase in width of epithelial tube and the absolute decrease in thickness of mesenchymal wall due to tension stresses elicited by the growth of the former. GROWTH MOTIVE FORCE PLATE 1 EBEN J. CAREY Lpith. Tube Tntest. wad Sub yy, Keo * Saale 29Q PLATE 2 EXPLANATION OF FIGURES 7 High-power drawing through intestinal wall at region marked a - b on fig- ure 1. X800. 8 High-power drawing through intestinal wall at region marked a - b on figure 2. XSO00. ABBREVIATIONS mit., mitesis g.f., granular fibrillae b.m., basement membrane c.m., circular muscle nucleus m.s., mesenchyme s.m., peritoneal epithelium 9 High-power drawing through intestinal wall at region marked a@ - b on figure 3. S800. 10 High-power drawing through intestinal wall at region marked a - b on figure 4. S00. ABBREVIATIONS mil., mitesis p.m., primordial mucosae cells b.m., basement membrane s.p., submucous nerve plexus m.s., mesenchyme l.f., longitudinal muscle fibrilla, eross- g.f., granular myofibrillae section c.m., circular muscle nucleus a.p., Auerbach’s plexus s.m., peritoneal epithelium 11 High-power drawing through intestinal wall at region marked a - b on figure 5. S800 diameters. 12. High-power drawing through intestinal wall at region marked a - b on figure 6. S800 diameters. ABBREVLATIONS mit., mitosis p.m., primordial mucosae cells b.m., basement membrane s.p., submucous nerve plexus m.8., mesenchyme Lf., longitudinal muscle fibrilla, cross- g-f., granular myofibrillae section e.m., circular muscle nucleus a.p., Auerbach’s plexus s.m., peritoneal epithelium c.f., continuous coarse myofibrillae 230 GROWTH MOTIVE FORCE PLATE 2 EBEN J. CAREY PLATE 3 EXPLANATION OF FIGURES 13 Longitudinal reconstruction of the cross-sections nos. 45 to 94. This figure together with the cross-sections represents a plotting of the exact location of mitosis in the epithelial tube. Figure 13 is depicted as a tube cut through the middorsal region at 12 o'clock and lying flat. 14 Represents figure 13 in graphie reconstruction; the flattened tube is folded up so that the edges of the middorsal cut are in apposition. The spiral paths of the mitotic figures are objectively evident. The apical region of the respective | paths are globular. This globular end is always directed cephalad. The basal end of the spiral path is directed caudad. The front and back aspects of the paths, as well as the cylindrical reconstruction is represented by solid and broken lines respectively. Sections 45 to 94 represent the cross sections of the epithelial tube of descend- ing colon. Section 45 is caudad; 94 is cephalad. The circles are numbered like a clock. Within the area enclosed by the two circles the dots are seen which represent the position and number of the mitotic figures. The arrows represent . _ the direction of the spiral mitotic path which is seen to be right-handed. The predominant path, however, is left-handed. The large intestine of twenty animals was plotted. In only one was the mitotic path found to present a dexio-_ tropic rotation. : PLATE 3 ROWTH MOTIVE FORCE EBEN J. CAREY 7AM a CAAA a TA ih AEE PE BL VG ws Sy we we OH \4 Pye a ET 9 2 LT PLATE 4 EXPLANATION OF FIGURES 15 Dorsoventral section through hind limb of 10-mm, embryo pig. ABBREVIATIONS m., mesenchyme eclo., ectoderm 16 Dorsoventral section through hind limb of 14-mm. embryo pig. ABBREVIATIONS il., blastemal ileum b.f., blastemal femur is., blastemal ischium m., mesenchyme d.p.m., dorsal premuscle mass b.t., blastemal tibia v.p.m., ventral premuscle mass eclo., ectoderm Schema of bone and muscle origin of thigh 17 Dorsoventral section through hind limb of 18-mm. embryo pig. Stage of cartilaginous femur. 18 Dorsoventral section through hind limb of 25-mm. embryo pig. Stage of inception of osseous femur. Bone formation beginning on tensile aspect of bent cartilaginous femur (¢. 0. l.) 19 Dorsoventral section through hind leg of 32-mm. embryo pig. 20 Dorsoventral section through hind limb of 50-mm. embryo pig. ABBREVIATIONS iL, ilium t.p., tensile periosteum (chondrium) is., ischium c.p., compressile Deniers (chon- r., rectus femoris drium) a., acetabulum v.i., vastus intermedius muscle h., head of femur a.m., adductor magnus muscle g.t., greater trochanter p., patella I'c., intermediate growing cartilage L.p., ligamentum patellae t.o.1., tensile osseous lamella J., femur c.o.l., compressile osseous lamella t., tibia N. B.—The most actively growing region of the thigh per mm. cross-section is the skeleton. This growth tends to draw out in tension the less actively grow- _ ing mesenchyme which results in the elongation forming the ventral and dorsal premuscle masses a.p.m. and v.p.m., figure 16. With increasing tension due to skeletal growth the individual definitive muscles are formed. Concomitant with muscle formation, skeletal condensation is seen progressively through the blastemal, cartilaginous, and osseous stages. (See text for full description.) | GROWTH MOTIVE FORCE PLATE 4 EBEN J. CAREY ‘ > Resumen por el autor, Oscar V. Batson. Universidad de San Luis. Deselectrificacién de las cintas de parafina por medio de la corriente de alta frecuencia. La cinta de parafina, al separarse de la navaja, con frecuecia se mueve, se adhiere a la navaja o es atraida por los objetos cer- canos. Esta dificultad, conocida generalmente como electri- ficacié6n, es muy molesta cuando se cortan secciones seriadas en tiempo frio y seco. La carga estitica es de caracter negativo y esta localizada en el tejido y no en la parafina. Esta carga se debe al rozamiento de la navaja sobre el tejido, porque si se corta un bloque de parafina sin tejido contenido en ella, no se produce cinta electrificada. La carga eléctrica puede suprimirse y prevenirse satisfactoriamente ionizando el aire ambiente por medio de un aparato portatil de alta frecuencia del tipo de ‘‘rayos violetas.’’ Se frota el microtomo con esmeril, se coloca oropel sobre el soporte de la navaja y se sustituye el electrodo de vacio del aparato de alta frecuencia, por una barra envuelta en oropel. El electrodo de oropel se dispone de tal modo que la descarga de la brocha tenga lugar a través del drea que recorre la cinta al ser producida por la navaja. El aparato debe mantenerse en marcha mientras se corte el tejido. Translation by José F. Nonidez Cornell University Medical College, N. Y. AUTHOR'S ABSTRACT OF THIS PAPER ISSUED BY THE BIBLIOGRAPHIC SERVICE, JULY 26 DE-ELECTRIFICATION OF PARAFFIN RIBBON BY MEANS OF HIGH-FREQUENCY CURRENT OSCAR V. BATSON Department of Anatomy, Saint Lowis University Electrification of the paraffin ribbon, particularly on the high- speed rotray microtome, has been responsible for the great dif- ficulties in serial work, particularly in cold, dry weather. Va- rious methods of eliminating the trouble have been tried with indifferent success. The problem was analyzed, first, as to the nature of the elec- trification; second, the source and reason for a collection of the charge; third, a means of discharging the electricity as it is formed. The nature of the charge was determined by means of the electrophorus. The charge on the metal plate of the electro- phorus is positive. The electrified paraffin ribbon is attracted to the metal plate of the electrophorus (positive) through a distance of several inches and is conversely repelled by the wax plate (negative). A ribbon possessing no charge is affected but little, so the charge on an electrified ribbon may therefore be said to be a negative one. The electrification of the ribbon comes about through the friction of the block on the knife and does not occur when paraffin alone is cut. Each section produces a certain amount of frictional electricity, and once a charge is formed, the paraffin as a non-conductor prevents its escape except into the air, and the escape into the air is dependent on the ionization of the gas particles to carry the charge. The solution for a de-electrification of the ribbon would there- fore resolve itself into terms of air ionization to permit a dis- charge of the electricity as it isformed. This was first attempted by using carnotite at the suggestion of Prof. Hermann Schlundt, of the University of Missouri. A bell jar containing several ounces of radio-active carnotite was placed over the microtome and knife so that the ‘active deposit’ might accumulate. The 2 ot <0 238 OSCAR V. BATSON experiment proved unsuccessful, although an electrified ribbon lost its charge in one-fifth the normal time when exposed to carnotite. The following procedure, however, has proved quite successful. A portable ‘violet ray’ high-frequency apparatus is employed, substituting for the usual vacuum electrode a rod of wood, 8 inches long, closely wound with wire-cored Christmas-tree tinsel. The idea of using tinsel must be credited to Dr. T. G. Lee, of the University of Minnesota. The apparatus was clamped in posi- tion so that the tinsel electrode stood parallel to the knife edge and about 2 inches in front of and above it. Additional tinsel was placed on the block holder and the knife supports. The microtome was grounded to a water pipe. The distance was ad- justed to give a brush discharge, i.e., a distance beyond the possi- bility of a spark discharge, and the vibrator was set so as to give a faint purple glow from the electrode in a darkened room. Under these conditions, bits of previously electrified ribbon, adhering to the knife support and: block, immediately dropped to the table. No electrification of the ribbon occurred with the microtome running rapidly, while the brush discharge was taking place. Curling of the ribbon recurred immediately when the current was turned off. Checking on the electrophorus, it was found that both positive and negative plates were discharged by being introduced into the high-frequency field. CONCLUSIONS 1. Electrification of paraffin ribbon is due to a negative charge which results from the friction of the tissue on the knife. It accumulates because of an insufficient ionization of surrounding air. 2. The charge can be completely and satisfactorily removed by ionizing the surrounding air with a portable high-frequency apparatus with tinsel electrodes, and grounding the microtome. 3. The distance of the tinsel electrodes must be adjusted to give a faint brush discharge. 4. The stream of the current is through the microtome, and disagreeable sparking to the operator is absent. A slight odor of ozone is neither disagreeable nor harmful. moo Bimini) Lilie alimony ee Wir Hh ty cis calyotanr 7 Al ; brre AS Y +4 TACO Astin HY CH ice t 4 ri Mite Tn rate Lito in” We teer ind jn re ars ce et ) tn Ct ehO ieee Pee CAAT Oi I Bi wien! Siri ole)! : | i ny pix Alo fare Tp mt) Aah shiv) ease Pa 7 pe ect rial te ait 6 ane er oe oe ore Peceree itu qhaalaty lie iret ye elem! im Pa APTS A OU cli die elas arya ay tea rody aa htt he) ‘anwar eee ith lal RUG aki Lerih’s edith bed Nernsess ihileaty ela ay, WiReOr Aci he mit et tiled oye din! PADionw (asdiig anladi boi ceil wor 3» semgttte A aA tue I+ este eds theo R iiarenertiys jpgaelel Simanieel glicyjoon! uations eu! Biveay fa sidoeial slp ATLA Fanviltchty ved eas 4 Be ocityn Vloruleeh ia oat hi, nvalo pnt NEA opr ilit Interv ino Ce mie: Gb ciromeriny TT ee ae) cc ae ome! col arya) aad) iertbets at Lil’ Aimar; “cae ara Apsiniop iyi! tines al dace thle « ‘ hehe Peds i tie vibe eet) enna oe) at uw cy val sats ably ORR AY bt Marre ex wr re MBO heady oPtinp Wren with ree VIM OhueriC e) ( Pada»! paris fe Agipethe) il 46 tntbioeiewl a! odwa ‘ “ay fli |) ise, (ie eh Alle (itt) 6 , fap aaah ae) We je er “5 Se ee a 4h eR Lh Fee APAU indian Geils Aji 5 i > ws ‘ays is J : | eer OF 4 | ipo aie is Lge }| eer i?) mele * Resumen por el autor, Henry Bayon. Universidad Tulane, Nueva Orleans. Un caso de membrana costocoracoide osificada fusionada con la clavicula. El sujeto objeto de este trabajo era un var6n negro, de muscu- latura bien desarrollada, y presenta al reflejar el pectoral mayor una placa cuadrilitera de hueso que se articula con el esternén y se extiende lateralmente hacia arriba hasta una distancia de media pulgada del proceso coracoides, con el cual esta unido por medio de una banda fibrosa. El hueso esta unido con la clavicula, que forma su borde superior redondeado y ensanchado; el miuis- culo subclavio falta y el pectoral menor se inserta en el extremo distal del hueso anormal. La indicacién de mi asociado, Dr. Baker, acerca de la posible conexién del hueso descrito con alguna anormalidad de la cintura pectoral es probablemente correcta. En la rana toro, Rana catesbiana, el hueso coracoides se extiende desde la escdipula hasta el estern6n y esta dividido en dos seg- mentos: Una ancha placa de hueso debajo, que es el coracoides propriamente dicho, y una barra delgada encima, el procoracoides, que representa la clavicula. En el desarrollo ontogénico de la clavicula de los mamfferos el cartilago en que aparece después el centro primario de osifieacién se deriva del coracoides primi- tivo. Plr consiguiente, es probable que el hueso anormal hal- lado corresponda al coracoides primitivo fusionado con sus de- rivados, es decir, con la membrana costocoracoide y la clavicula. Huntington cita la presencia de uno o dos nédulos cartilaginosos en la membrana costocoracoide. En el sujeto descrito en este trabajo la mayor parte de la membrana costocoracoide (fascia coracoclavicular) y el miisculo subclavio se han osificado. Una prueba mas evidente de la identidad del hueso con el ligamento costocoracoides y la membrana es su perforacién por la vena cefdlica, cuya desembocadura en la vena axilar, es por otro lado normal. Translation by José F. Nonidez Cornell University Medical College, N. Y, AUTHOR'S ABSTRACT OF THIS PAPER ISSUED BY THE BIBLIOGRAPHIC SERVICE, JULY 26 A CASE OF OSSIFIED COSTOCORACOID MEMBRANE FUSED WITH THE CLAVICLE HENRY BAYON Department of Anatomy, Tulane University ONE FIGURE The subject, a negro male, with excellent muscular develop- ment, presents after reflecting the pectoralis major a quadri- lateral plate of bone articulating with the sternum and extending lateralward to above half an inch from the coracoid process, to which it is united by a fibrous band. The bone is fused with the clavicle, which forms its upper rounded and expanded border; the subelavius muscle is absent and the pectoralis minor inserts at the distal end of the abnormal bone. The suggestion of Doctor Baker, my associate, that the condition might be connected with some abnormality of the pectoral girdle is probably quite correct. In Rana eatesbiana, bullfrog, the coracoid bone extends from the scapula to the sternum and is divided into two segments: a broad plate of bone below, the coracoid proper, and a slender bar above, the procoracoid, representative of the clavicle. In the ontogenetic development of the mammalian clavicle the cartilage in which the primary center of ossification is further developed is derived from the primitive coracoid. It is conse- quently quite probable that the abnormal bone here found corre- sponds to the primitive coracoid fused with its derivatives, namely, the clavicle and the costocoracoid membrane. Huntington cites the presence of one or two cartilaginous nodules in the costocoracoid membrane. In the subject here presented the greater part of the costocoracoid membrane (cor- acoclavicular fascia) and the subclavius muscle have undergone ossification. A further evidence of the identity of the bone with 239 240 HENRY BAYON the costocoracoid ligament and membrane is its perforation by the cephalic vein, which otherwise normally drains in the axillary vein. Cephalic vein ,Unossified portion of costocoracoid ligament ! ! 1 Ossitied Costocoracoid inembrane ! ! Resumen por el autor, Henry Bayon. Universidad Tulane, Nueva Orleans. Diferencias raciales y sexuales del apéndice vermiforme. E] objeto del presente trabajo es el describir las diferencias que existen entre el apéndice del blanco y del negro, las cuales pod- rian explicar la mayor susceptibilidad para la apendicitis en la raza blanea, si es que existe tal susceptibilidad. Las observa- ciones efectuadas incluyen diferencias sexuales y raciales en el tamano, musculatura, nimero relativo de linfocitos y criptas, y vascularizacién del érgano. Del eximen microscépico de sec- ciones transversales de cien apéndices se deduce que las diferen- cias mas salientes en las dos razas se refieren al ntimero mas elevado de linfocitos en el apéndice del hombre blanco y la mayor riqueza vascular del mismo 6rgano en el negro Las estadisticas del Hos- pital de Caridad de Nueva Orleans, que fueron consultadas inci- dentalmente, parecen confirmar una susceptibilidad mayor de la raza blanca a las enfermedades de otros 6rganos linfdticos, tales como las ténsilas palatinas y faringeas. Translation by José F. Nonidez Cornell University Medical College, N. Y. : pn AUTHOR'S ABSTRACT OF THIS PAPER ISSUED BY THE BIBLIOGRAPHIC SERVICE, JULY 26 RACIAL AND SEXUAL DIFFERENCES IN THE APPENDIX VERMIFORMIS HENRY BAYON Department of Anatomy of Tulane University About thirty years ago the appendix had practically no his- tory, either physiological or pathological. Howard Kelly, in his extensive work on the vermiform appendix and its diseases, recalls that only in 1824 was the appendix recognized as an organ susceptible to disease arising primarily in its own structure, although mention was made of isolated cases such as Mestivier’s recorded in 1759 in which a postmortem examination revealed a pin @oncealed in the appendix, which had caused inflammation resulting in the death of the patient. This and other similar cases related in Kelly’s work show that even in the eighteenth century the appendix was recognized as suscep- tible to inflammatory lesions, but it was not until 1886 that the appendix was placed in the category of organs susceptible to surgical disease. From that time the daily harvest of appen- dices has steadily increased. At the beginning of that period we hear Frederick Treves, one of the pioneers of appendectomy, clamoring against the indiscriminate removal of the appendix, which he brands as a needless and illogical recklessness. Since that time a number of speculative statements have appeared regarding the purpose of the appendix, usually more or less fanciful and sometimes positively grotesque. From the high office of abdominal tonsil we find it elsewhere relegated to the abject rdle of the ordinary mechanical grease cup. In - studying the minute structure of the appendix, it is true that large numbers of lymphocyte accumulations are found within its walls, but at best these amount to little compared with similar accu- mulations found elsewhere in the intestinal canal and are in no way different from the solitary and aggregated lymphatic nodules. 241 242 HENRY BAYON Needless to say that the grease-cup theory finds no support. from whatever angle the organ is viewed. It evidently origi- nated in 1749 from an old theory of J. Vosse, who claimed that the glands of the cecum were not sufficient to moisten its con- tents and that the function of the appendix was to provide addi- tional secretion. It is not the purpose of the present study, however, to discuss the function of the appendix nor the conditions which call for its removal. It was undertaken with a view to possible differences in structure, both as to race and as to sex. In considering disease of the appendix, the following questions suggested theniselves: Is appendicitis more frequent in the white race than in the negro? Is the disease more prevalent in one or the other of the sexes? And if there are racial and sexual differences, is there anything in the structure of the appendix to account for such differences? The first question, if records and Surgical experience are given consideration, is answered decidedly in the affirmative. The statistics, however, on this, as unfortunately on a great many other subjects, are totally unreliable, even bags tabulated intelligently and in good faith. The eagerness displayed by the medical profession in coming before the public, both in print and in lecture, no doubt in a great many instances with very laudable intent and good effect, places Within reach of the more intelligent layman much of the interpretation of his own ills and pains. He seldom ignores the signs and symptoms of appendicitis. As a result, the first tinge of pain in the right iliae region will sound a loud note of warning, followed by a rush to the surgeon, who at once proceeds to remove the appendix, in which postoperative examination fre- quently reveals little or no inflammatory change. This state- ment, however, is made with due regard to surgical prudence which takes no chances in a condition where prompt treatment means so much to the patient’s safety. At this juncture it may not be inappropriate to refer to the opinion so frequently ex- pressed, that appendicitis is on the increase. That the num- ber of appendectomies has increased there can be no question, but that appendicitis is increasing is more than doubtful. 4 ‘ RACIAL DIFFERENCES—APPENDIX VERMIFORMIS 243 In contrast with the alertness of the better classes and their readiness to part with an offending organ, is the ignorance and apathy of the poor negro concerning his disease and the counter- indifference of his medical attendant. Acute indigestion or heart failure are convenient and ready forms for his death certifi- cate. Acute gangrenous appendicitis may have caused his death, but his tardiness in seeking medical aid or the lack of interest of his doctor, who comes in when the patient is dying or dead, are in many instances responsible for the error in diagnosis. Hence a possible flaw when records are considered, in passing judgment as to the racial susceptibility to appendicitis. But if statistics are negative in deciding susceptibility, might there not be some structural peculiarity which would make cer- tain appendices more vulnerable than others? Some time ago, in a casual examination of appendices in the dissecting-room, I was struck with the stout musculature of the negro organ as compared with the flabby membranous appearance of the white appendix. Obviously, a fecal stone or a foreign body would have far less chance of becoming impacted or retained in a ro- bustly muscular appendix with active peristalsis possible than in one whose weaker walls would not only fail to rid the organ of its offending contents, but in consequence of the organ’s easier distention would favor the storing up of enormous numbers of pathogenic bacteria. Hoping to arrive at some tangible facts regarding structure which might cast some light on racial and sexual peculiarities, I have examined 100 appendices and tabulated them according to race and sex. The specimens employed comprised 53 negro appendices, 31 male and 22 female, and 47 white appendices, 11 male and 36 female. METHOD OF PREPARATION The appendices were at first fixed in 10 per cent solution for- malin, then mordanted in the following fluid: 35 per cent aqueous solution bichromate of potash.................. 92 Formalin (40 per cent formaldehyde)...................0ceeseeceees 4 SUACIAFAUGLIO AOL Werner TATRA SCA anttaxc inn bce Stacia wate’ 5 244 HENRY BAYON The appendices were then imbedded and sectioned in celloidin, stained by Delafield’s hematoxylin and counterstained in eosin. LEVELS AT WHICH STAINED SECTIONS WERE TAKEN In order to obtain more reliable data, dissecting-room appen- dices were not considered. Appendices so diseased as to show disorganization or destruction of their tissues were avoided. Only recently removed appendices gathered from autopsies and abdominal operations at Charity Hospital and Touro Infirmary of this city and preserved in formalin solution were used. The material included twenty-five slides of cross-sectioned appen- dices borrowed from the pathological department of Charity Hospital. Each appendix was measured in length and in width and cross-sectioned two or three times from base toward the apex. The average length, in all cases considered regardless of race or sex, was 9.2 em. in seventy-one specimens (table 1) and the average width 6.2 mm. in ninety-eight specimens. The length and width of the 100 appendices were not all available. The length was not mentioned in the histories of the twenty-five © Charity Hospital slides, and in four of the specimens prepared by myself part of the organ was missing. The width was taken from the mounted cross-sections in all cases except in two, the specimens having been previously opened eo the pathologist for inspection. Tables 2 and 3 show a sexual aitenenge's in favor of the male, giving an average of 9.6 em. (length) and 6.5 mm. (width) in thi male against 8.7 em. (length) and 6 mm. (width) in the female. tables 4 and 5, the racial difference (in the two tables) show an — average of 7 em. (length) and 6.5 mm. (width) in the white and 11.3 em. (length) and 6 mm. (width) in the negro. It may well be objected that in tables 2, 3, 4, and 5 the infer- ences must be unreliable, the number of cases being too restricted. In table 1, however, which deals with the average length of the appendix, regardless of race or sex, the same objection does not pre- vail. ‘The slight difference in size between the male and female appendix is all that might have been expected, although that, TABLE 1 Racial and sexual LENGTH 9 cases— 8 cm. 20 cases—11.3 cm. 37 cases— 6.1 em. 5 cases—11.3 cm. Wikfevm ale taser Sei cee pe iscsi Negro male..... SoS eee Wihttefemales. ... 0 c0se2 So Weprofemale:. -.5....5....- WIDTH 11 cases—7 mm. 28 cases—6 mm. 37 cases—6 mm. 22 cases—6 mm. 71 cases ay. 9.2 cm. ' 98 cases av. 6.2 mm. TABLE 2 Racial, male LENGTH 9 cases— 8 em. 20 cases—11.3 cm. VU ar) ee AVE PRO MNISIG Me hen sosye = 2s sais 29 cases av. 9.6 cm. TABLE 3 Racial, female WIDTH 11 cases—7 mm. 28 cases—6 mm. 39 cases av. 6.5 mm. LENGTH Wihitefemalle a: .2)05.5 55222 -. Wegromemale. 9.7... 352---- 2: 37 cases— 6.1 em. 5 cases—11.3 em. 42 cases av. 8.7 cm. WIDTH 37 cases—6 mm. 22 cases—6 mm. 59 cases av. 6 mm. TABLE 4 Sexual, white LENGTH WIDTH 9 cases—8 cm. 37 cases—6.1 cm. WBE TAGs se acc eros F 5 sar Wihthe fergales co. .csccescc ces 46 cases av. 7 em. 11 cases—7 mm. 37 cases—6 mm. 48 cases av. 6.5 mm. TABLE 5 Sexual, negro LENGTH 20 cases—11.3 cm. 5 cases—11.3 em. BSPTONAL BS, 2.5. stre ness mwas Ce MNepro demale........-----.s6 25 cases av. 11.3 cm. 245 WIDTH 28 cases—6 mm. 22 cases—6 mm. 50 cases av. 6 mm. 246 HENRY BAYON together with racial differences, would seem to offer no solution to the problem at issue, namely, structural peculiarity bearing on susceptibility to inflammation. The tabulations were simply included as a matter of general interest. The field which seemed most promising was the microscopic survey of the transverse sections. This consisted in measuring the thickness of the longitudinal and circular muscular tunics expressed in terms of microns together with noting the relative amount of lymphocytes, fat and crypts and the vascularity of each appendix, classifying the specimens into three categories, rich, moderate and poor, as indicated in table 6. TABLE 6 Based upon 100 specimens MUSCULA- TURE LYMPHOCYTES PAT CRYPTS VASCULARITY IN MICRONS ‘ 3 3 3 2 = £ £ é £ = s e/2/3/31812/3) 81321312 ae a o = = a = = a = = = = a = per | per | per | per | per | per per | per | per | per | per cent | cent | cent | cent | cent | cent | cent | cent | cent | cent | cei cent N. M.—31 C. /247.6/350.8) 16 | 22 | 62 | 23 | 32 | 45 | 19 | 55 | 26 | 64 | 29] 7 N. F. —22 C./270.4/375 .3) 14 22 | 41 | 41 | 18 | 14 | 36 | 50 | 54 | 27 | 19 W. M.—11 C./270.4/435 9) 64 | 18 | 18 | 27 | 55 | 18 | 36 | 9 | 65 | 18 | 18 | 64 r ./241.2)392.8] 47 | 44 | 9 | 59 | 29 | 12 | 62 | 23 | 15 | 16 | 21 | 73 A glance at the figures disproves the first impression regarding musculature. It is, therefore, quite evident that immunity from appendicitis in the negro, if such exists, cannot be accounted for by a stronger peristaltic wave. Indeed, the measurements show a preponderance of muscular tissue in the white appendix. The racial and sexual differences in the percentage of fat con- form with the general distribution of fat elsewhere in the sexes and in the two races. The negro as a race carries less fat in the average than the white, and in both races the female carries more than the male. The difference in the number of crypts retained is decidedly in favor of the white appendix. This would seem to indicate less RACIAL DIFFERENCES—APPENDIX VERMIFORMIS 247 susceptibility to inflammation. Hence, the study of structure in this particular feature, far from confirming disease statistics, offers decided opposition and is quite suggestive to the reverse. The difficulty, however, presented by the crypts is offset very singularly by the findings regarding both the lymphocytes and vascularity. In the white appendices, 64 per cent male and 47 per cent female were found rich in lymphocytes, and 18 per cent male and 16 per cent female were found rich in vascularity. Comparing this with the findings for the negro appendix, 16 per cent male and 14 per cent female were rich in lymphocytes and 64 per cent male and 54 per cent female were found rich in vascularity. In the cases here examined the ratio in the two races between lymphocytes and vascularity is inverted—the richer in lympho- cytes, the poorer the vascularity seems a characteristic of the white appendix, whereas the reverse obtains for the negro appen- dix, in which the scarcity of lymphocytes corresponds with rich vascularity. From the figures the fact stands out that the white appendix is richly lymphatic and poorly vascular and the negro organ just the reverse. In the white appendix are found two conditions predisposing to inflammation more especially of the gangrenous type—a rich supply of lymphocytes indicating predisposition to inflammation and poor vascularity favorable to gangrenous changes. It may be objected that since the cases were tabulated regard- less of health or disease, the prevalence of the appendices rich in lymphocytes might result from inflammatory action. The objee- tion is met by the fact that, although in some cases operation was performed for appendicitis, in a great many other cases operation was performed for disease other than appendicitis, the appendectomy being performed simply as a matter of prudent routine in anticipation of possible future appendical trouble. But even if on that account, the high percentage of organs rich in lymphocytes found in the white cases be considered of negative value, the fact remains that these specimens show a low per- centage of vascularity, and if inflammation alone could suggest increased lymphatic richness, it should also accentuate vascu- larity, which is quite contrary to the finding. 248 HENRY BAYON Racial differences in the appendix suggested that corresponding differences might also exist in other diseases of the lymphatie system. Statistical inquiry into the relative number of tonsil and adenoid disease in the two races demonstrated that in 4759 patients admitted into the Charity Hospital during the first three months of 1917, 2258 were negroes and 2501 were whites. In the 2258 negro cases there were 35 tonsil cases and 8 adenoid eases. In the 2501 white cases there were 95 tonsil cases and 21 adenoid cases. Table 7 shows that the number of tonsil cases was more than twice as great in the white than in the negro and that the num- ber of adenoid cases was twice as large in the white. TABLE 7 TONSIL CASES ADENOID CASES 2258 negro patients................ 35 (0.015 per cent) 9 (0.004 per cent) 2501 white patients................ 95 (0.037 per cent) | 21 (0.008 per cent) In these tonsil and adenoid cases figures may hold out equivocal interpretation: we are well aware that more whites than blacks are prone to become nervous about health conditions and the same suggestion regarding the advisability of parting with the appen- — dix prevails for tonsils and adenoids. It rests with the specialist whether the organs show sufficient evidence of disease to justify operation and the administration of an anesthetic—always a grave responsibility. Be that as it may, if each tonsilectomy and adenoidectomy means diseased palatine or pharyngeal ton- sil, the unavoidable and indisputable inference is that tonsil and adenoid disease is more prevalent in the white than in the negro. The same Charity Hospital records for the first three months of 1917 show a total of twenty-three negro cases of appendicitis against eighty-five white cases. With due allowance for the doubtful trustworthiness of statistics considered from the stand- point of their face value, it may be safely assumed that when viewed in the light of histological findings above submitted, they welt RACIAL DIFFERENCES—APPENDIX VERMIFORMIS 249 are at least quite suggestive of greater susceptibility of the white race than the negro to appendicitis. Differences in the lymphatic system of the white and negro races may also be inferred from the findings of Bean and Baker, which appear in the Journal of Physical Anthropology, vol. 2, no. 1, 1919, under the title of ‘‘Some Racial Characteristics of the Spleen Weight in Man.” Over 1500 white and about the same number of negro spleens are considered, showing a decided difference in weight in favor of the white spleen. These findings are well correlated to those submitted in the present study and seem to prove that the white race is more subject to lymphocytic stasis than the negro. SUMMARY 1. The musculature of the white appendix is not weaker. Indeed, it seemed slightly stronger than that of the negro. 2. The female appendix is richer in fat than the male. 3. The white appendix is richer in crypts. 4. The white appendix is rich in lymphocytes and poor in vascularity and the negro appendix rich in vascularity and poor in lymphocytes. 5. The average size of the appendix is 9.2 em. in length and 6.2 mm. in width. 6. The white appendix is shorter and wider than the negro appendix. 7. The male appendix is longer and wider than the female appendix. HUMAN PARASITOLOGY, wirn Notrs on BacrerioLtocy, My- coLocy, Lasoratory D1aGNosts, HremMaroLoGy AND SEROLOGY, by Damos Rivas, B. 8. Biol., M.S., M.D., Ph.D., University of Pennsylvania, Illustrated. 716 pages, W. B. Saunders Company, Philadelphia, Pa. 1920. EXTRACTS FROM PREFACE A half century ago medicine was more an art than a science. The doors of American medical colleges stood wide open to welcome all who came as students, and if they showed a desire to learn, possessed enough elementary education to enable them te read their text-book and write their examination papers no questions were asked as to their acquaintance with the physical and biologic sciences. There was no science of parasitology. Parasites were zoologie curiosities that occasionally intruded into the sphere of medical activity. Now all has changed. The necessities of commerce have led to such extensive geographic explorations that the entire surface of the earth has been explored and charted. Ethnologic investigators have uncovered the location, life and habits of many formerly unknown peoples. The general rapid advance of scientific knowledge, especially the progress of physics, chemistry and biology, inevitably reacted upon medicine, stimulating the scientific spirit, demanding research upon its obscure problems, and requiring a new t'ype of student whose prepa- ration for medicine must include at least an elementary knowledge of the collateral and fundamental sciences. The author has for twenty years interested himself in parasitology and has had the good fortune to have studied in public health labora- tories at home and abroad, and to have served on sanitary commis- sions. After years of teaching he now endeavors to bring together the facts of parasitology in a form suitable to the needs of the student and physician. The following pages reflect his personal experiences and present the facts of the subject in a form sufficiently brief to make it a text-book—the modern tendency is to be enecyclopedic—and sufficiently full not to omit any important fact or method. Sunil “= > ] by f “ > Atti it Pais Piney tint) ie 7 y » 5 Lo R : ; : 7 p 8 . +e * Jetpovrtere one en ei \ ' ii. j ‘ pail rit wi By da) uy Li : php] j 4 ran Gilpin. Ps shad taty 9 jis) BE i Owl ied sity Wily ij athe igi a v3 tydy Wy Tae | thw ? i> wiht iets ghioviey i Mw ay AN ink (eyes ake BBs omni ees : bivdiir> ait itd doug oh tf ve ] rages witty ie Watt dike iy} te Vi fas ‘yi, write @ se o_o Adi. vent ith ay aii i" ) gf chet ih oee ots 5 Jee ; aio 77 ’ qT 7 wil a os inary j ‘allie / a ee = 4 yo ae | ‘ ~ ?- “ - ¥ Md be Resumen por el autor, Carl G. Hartman. Universidad de Texas. Los fenémenos del parto en el opossum. En oposicién a lo que se cree generalmente, el embrién del opossum, al final del periodo de gestacién, que dura diez dias, camina por sus propios esfuerzos desde el orificio vaginal hasta la bolsa marsupial, en la que encuentra la mama. La madre no ayuda al embri6én durante su paso desde la vagina a la bolsa, pero le lame para despojarle del liquido coriénico, cuando sale— por la vulva. Lo mismo que en el caso de las especies australianas Perameles y Dasyurus, descrito por Hill, los embriones alcanzan el canal vaginal medio no por los canales vaginales laterales, sino por un ttinel que aparece de novo en el tejido conjuntivo situado entre la uretra y los canales vaginales laterales. Translation by José F. Nonidez Cornell Medical College, New York AUTHOR'S ABSTRACT OF THIS PAPER ISSUED BY THE BIBLIOGRAPHIC SERVICE, SEPTEMBER 13 STUDIES IN THE DEVELOPMENT OF THE OPOSSUM DIDELPHYS VIRGINIANA L.! V. THE PHENOMENA OF PARTURITION? CARL G. HARTMAN The University of Texas, School of Zoology THE METHOD OF TRANSFER OF YOUNG TO THE POUCH The literature So far as the writer has been able to discover, there exists in the literature only one account of the actual birth of any mar- supial, notwithstanding the abundance of opossums in America and the variety of all marsupial fauna in Australia. Nor does that foremost of all students of marsupial embryology, Prof. J. P. Hill, refer to this topic, although on one occasion (’00, p. 371) he killed a specimen of Dasyurus after ‘‘one only of the young had been born.”’ Meigs (’47) and Selenka (’87) examined pouch young of the opossum immediately after birth, but made no observation on parturition. The single recorded observation referred to is that of Dr. Middleton Michel, of South Carolina (’50), who, on January 28, 1847, witnessed the copulation of a pair of opossums, and fourteen days and seventeen hours later saw the birth of the foetuses. In order to show, however, that Doctor Michel failed to see the actual passage of the young to the pouch, two essen- tial paragraphs on the point at issue are here quoted: 1 Parts 1 and 2 (History of the early cleavage—Formation of the blastocyst) appeared in the Journal of Morphology, volume 27, number 1, March, 1916; and Parts 3 and 4 (Description of new material on maturation, cleavage and ento- derm formation—The bilaminar blastocyst) appeared in the Journal of Mor- phology, volume 32, number 1, March, 1919. These four parts may be obtained from the publishers. 2 Contributions from the School of Zoology, the University of Texas, no. 143. 251 252 CARL G. HARTMAN The pregnant female was found standing on her hind legs; her body was much bent, and propped up against the corner of the cage; her muzzle in immediate contact with the cloacal opening, which was red, tumefied and distended; a young appeared at the opening, and was conveyed by the mother’s mouth to the pouch, or perhaps was rather licked in, as her tongue seemed busily employed within, around and about the pouch. The young are expelled first into the vaginal cul-de-sac, in which they remain for a short time, on the contraction of which they are forced along the vaginal canals one by one; parturition is thus very much prolonged, owing to the circuitous route which the young are obliged to take, and the delay thereby occasioned between the birth of each is the object of the peculiar modification of these parts in this animal, as it affords the requisite time employed in the conveyance of the young to the pouch and their adaptation to the teat. It is quite clear from the language of this quotation that Doc- tor Michel did not actually witness the migration of the embryos and that he merely guessed at the method employed by the mother, since he was not sure whether she used her mouth or her tongue. It will, moreover, be shown below that Doctor Michel was also mistaken in presuming that the young at birth pass out by way of the lateral vaginal canals. The observations recorded below indicate that the marsupial female does. not actually transfer the foetuses to the pouch and that Doctor Michel’s interpretation, as well as the prevailing notion in accordance therewith, is not borne out by the facts. Some preliminary observations A series of observations and experiments during the last four or five breeding seasons of the opossum had enforced the convic- tion that the young reach the pouch and find the teat by their own efforts and are not placed on the teats by the mother’s tongue or lips. Why should it be necessary, one may ask, in the absence of actual observation, to presume such undue skill and sensitivity in the adult when a pure instinctive reaction on the part of the young will suffice? On several occasions I experimented with newly born pouch young, gently removing them from the teats to which they had firmly attached themselves by means of their powerful tongues. DEVELOPMENT OF THE OPOSSUM 253 I quote from my notes in one case (no. 301, experimented upon in the presence of Dr. C. H. Heuser, of The Wistar Institute, January 20, 1917): Female tied down and pouch opened. Young which were removed from teats crawled about, moving hands alternately, as in swimming. Were able to crawl among hairs and find teats by their own efforts. One specimen, removed three times, found teat each time and three others found teats after wandering about. These experiments certainly argued strongly in favor of some little independence of action on the part of these ‘embryos,’ a term that Doctor Meigs (’47) would have us abandon when speaking of these “breathing, sanguiniferous, digesting pouch young.” On February 6, 1917, on opening specimen no. 402 under anesthesia, I was surprised to find a collapsed but very vascular uterus, as if birth had just taken place. This proved to be the case, for on removing the animal from the table I found that the entire litter of foetuses had been expelled during the operation. They were mostly still alive, entangled in foetal envelopes and immersed in the foetal fluid. To some of the foetuses the um- bilicus was still attached; others were free, but no navel could be seen in any case. None of the foetuses, even after being freed of membranes and liquids, could crawl about, as they were ap- parently drowned in their own embryonic fluid. It seemed likely, therefore, that the embryos, on emerging from the vagina, need the assistance of the mother to lick away the fluid expelled from them, and this was later verified by actual observation. Embryos near term were also removed from the uterus, freed of their envelopes, and allowed to crawl about over the mother, which they did for at least fifteen minutes. On one occasion I removed one uterus three days before term (no. 131), and about the time that birth was to be expected from the remaining uterus I injected some pituitrin subcutaneously, hoping to witness parturition thus brought on. But owing to the fact that abortion had previously taken place, as was after- ward learned, only mucus was extruded from the genital orifice. 254 CARL G. HARTMAN It is interesting to note, however, that after the injection of pituitrin the female licked out the pouch at frequent intervals, an act which probably always precedes parturition. The birth of the opossum Specimen no. 443 was brought to the laboratory February 2, 1920, having been captured uninjured several nights before. She was a healthy female of medium size, and by palpation of the mammary glands, after the method which I have described at another place (’19, p. 24), I recognized her as pregnant and likely to give birth within several days. I removed her to my home, where she was kept under observation night and day, and the suecess which attended the undertaking is largely due to my wife’s enthusiasm and perseverance. The animal was placed just outside a window in a cage illu- minated within by a red electric light, which arrangement was least disturbing to the animal as she was insulated against noises from within the room; the sight of persons moving about in the room caused little response on the part of the animal, but slight noises near the cage startled her greatly. At 10:30 p.m., February 6, 1920, the animal showed signs of restlessness and soon began cleaning out the pouch, which she did about four times. Then began a short series of spasmodic contractions of the abdominal wall, after which she came to a sitting posture with legs extended. At no time did she stand on her hind legs, as Doctor Michel seems to have observed, for such « position is certainly strained and unnatural. I once had an opossum give birth while she was confined in a burlap sack in which she was carried to the laboratory. In this case it was as- suredly impossible for her to stand on her hind legs during par- turition. After assuming the sitting posture, our specimen bent her body forward and licked the vulva; however, her position at this time was such that we could not see the embryos, which very likely passed into the pouch with the first licking of the genital opening. Hence we went to the outside where we could plainly hear her DEVELOPMENT OF THE OPOSSUM 255 lap up the chorionic fluid; then suddenly a tiny bit of flesh ap- peared at the vulva and scampered up over the entanglement of hair into the pouch to join the other foetuses, which now could be seen to have made the trip without our having observed them. Unerringly the embryo traveled by its own efforts; without any assistance on the mother’s part, other than to free it of liquid on its first emergence into the world, this ten-day-old embryo, in appearance more like a worm than a mammal, is able, immedi- ately upon release from its liquid medium, to crawl a full three inches over a difficult terrain. Indeed, it can do more: after it has arrived at the pouch it is able to find the nipple amid a forest of hair. This it must find—or perish. Having now satisfied ourselves as to the manner in which the young opossum reaches the pouch, we etherized the female, hoping still to find some of the embryos within the genital tract. But it happened that we had witnessed the last of the litter make the journey. The pouch contained a squirming mass of eighteen red embryos of which twelve were attached, though thirteen might have been accommodated. The remainder were, of course, doomed to starvation. Even some of these un- fortunates, however, held on with their mouths to a flap of skin or to the tip of a minute tail, while several continued to move about. With the mother under the influence of ether, we now gently pulled off a number of embryos from the teats in order to test their reactions. The teats had already been drawn out from about a millimeter in height to double that length, doubtless by the traction of the embryo itself, for the bottom of the pouch certainly presented a busy scene with each member of the close- pressed litter engaged in very active breathing and sucking movements. One detached young, placed near the vulva, crawled readily back into the pouch. Two or three others regained the teats after some delay, and one wanderer, which lost out in the first scramble, found a vacated teat and attached itself even after twenty minutes’ delay, showing that the instinct to find the teat persists for some time. If the skin be tilted, the embryos, can 256 . CARL G. HARTMAN be made to travel upward and even away from the pouch, for they are negatively geotropic. For locomotion the embryo employs a kind of ‘overhand stroke,’ as if swimming, the head swaying as far as possible to the. side opposite the hand which is taking the propelling stroke. With each turn of the head the snout is touched to the mother’s skin as if to test it out, and if the teat is touched, the embryo stops and at once takes hold. It is thus apparent that the opossum embryo at birth possesses not only fairly well-developed respiratory and digestive systems, but that it has attained a neuromuscular development sufficient to enable it to find its place in the pouch where food and shelter await it. The number of pouch young Most female opossums possess thirteen teats, of which usually only the posterior eleven are functional. I have often found as many as eleven pouch young attached, but only in two cases as many as twelve. Doctor Meigs (’47) on one occasion found thirteen. I have seen litters consisting of fifteen, seventeen, and eighteen newly born young in the pouch, with as few as seven - attached to teats, and have removed from pregnant uteri as many as twenty-two normal foetuses near term. Such overproduction with consequent mortality has already been pointed out for the opossum and other marsupials (Hill, ’10, ’11; Hartman, ’19). Folklore In the popular mind the generation of no animal is so shrouded in mystery as that of the opossum. From New Jersey to Texas several beliefs are current which it might be well to state at this point. There is a wide-spread notion that copulation takes place in the nostril of the female and that the ‘fruit of conception’ is blown into the pouch. This superstition rests upon two observed facts: first, that the opossum penis is dichotomous and, second, that the female licks out the pouch immediately prior to parturition. DEVELOPMENT OF THE OPOSSUM 257 Another notion is that the pouch young is organically connected with, or ‘grown to,’ the teat, in fact so intimately that bleeding results from the forced separation of the pouch young. Dactor Meigs (47) already showed that this is not the case. Doctor Meigs mentions and refutes the idea prevailing in his time that the pouch young produces a teat wherever it happens to take hold of the skin in the pouch. Finally, it is often stated that the marsupial mother pumps milk into the pouch young. Whether or not thisis true the writer does not know, but certain it is that from the very beginning the young opossum engages in active sucking movements. THE PASSAGE OF THE FOETUSES FROM THE UTERUS As is, of course, well known, the opossum, as a member of the order Marsupalia, possesses two uteri. These do not communi- cate posteriorly, but open each into a separate shallow cul de sac, on either side of a median partition. Each cul de sac communi- cates laterally with a loop, the ‘lateral vaginal canal’ (Hill, ’97), which curves laterad, then caudad and mediad, until near the midline the two canals almost touch; and from this point back- ward they lie parallel until they empty into the ‘median vaginal eanal’ (Hill, 97) or urogenital passage (Owen, ’68). The lateral vaginal canals thus resemble two question marks placed face to face; the curved portions lie in the body cavity, the ‘stems’ are imbedded in the connective tissue of the urogenital strand. The urethra forms a third parallel tube, lying in the midline ventrad to the straight portion of the lateral vaginal canals and emptying with them into the median vaginal canal. In two Australian species Hill (Parameles, Dasyurus; Hill, 98, 00) made the surprising discovery that the embryos at birth do not pass out through the lateral vaginal canals, but break through by a cleft-like rupture, the ‘pseudovaginal canal,’ directly into the median vaginal canal from the culdesac into which the os uteri opens. The new passage is described as a split in the connective tissue, at no time lined with epithelium and containing fragments of foetal membranes together with leucocytes and maternal blood clots. 258 CARL G. HARTMAN I have on several occasions demonstrated in the opossum the existence of the pseudovaginal passage discovered by Hill. In specimen no. 402, already mentioned as aborting under an ab- dominal operation, one could follow a bloody trail direct into the median vaginal canal exactly as Hill had described it The hemorrhage was less severe in no. 443, the birth of whose young has been described above, but the new passage was easily demon- strable. The organs were fixed in Bouin’s fluid and sectioned. The findings are quite in accord with those of Hill. The pseudo- vaginal canal is seen to be simply a slit in connective tissue be- tween the bladder and urethra ventrally and the caudal ends of the lateral vaginal canals dorsally. In formaldehyde prepara- tions of the organs taken from non-pregnant females such a pseudovaginal passage can with great ease be pushed through; that is, the urethra may very readily be separated from the parts dorsal to it. It appears quite certain that the contraction of the abdominal and the uterine walls is sufficient to force the new pas- sage at the time of birth. The embryonic envelopes are partly retained within the uterus, a fact already noted by Osborn (’87) for the opossum, and partly scattered along the median vaginal canal. None were found in the lateral vaginal canals either by Osborn or by the writer. It is possible that an embryo may even drag parts or all of its foetal membranes to the exterior, in which case the mother may lick it free; but my only evidence on this point is the presence of the foetal membranes about many of the embryos in the case of one abortion. The opossum should therefore be added to the list of marsu- pials which force the ‘pseudovaginal canal’ at parturition. One might suppose from this that the lateral vaginal canals would possess a special function. The writer believes with Hill that they function as receptacula seminis, since in the marsupials several days elapse between copulation and ovulation. In the opossum the enlargement of the canal is one of the striking fea- tures of the prooestrus period. At oestrus they have attained an enormous size and are filled to turgidity with a thin, lymph-like fluid. Soon after ovulation they shrink almost to the resting DEVELOPMENT OF THE OPOSSUM 259 stage and are filled with cheesy masses of epithelial cells, which remind one of a similar phenomenon described by Stockard and Papanicolaou (’17) for the guinea-pig at oestrus. ADDENDUM Several months after the foregoing paper had been received by the editor of this journal the writer received a note from Dr, H. H. Donaldson, of The Wistar Institute, in which he stated that he had learned from Dr. N. Hollister, Superintendent of the National Zoological Park, Washington, D. C., of a published account of parturition in Macropus rufus, the dlece kangaroo. The article in question is in the nature of a communication by the observer, Mr. A. Goerling, to the ‘Western Mail,’ of Perth, Australia, and was published January 3, 1913. Doctor Hol- lister’s kindness in having the article copied makes it possible to present this interesting account to the readers of The Anatomi- cal Record and thus render it more generally available to zo- ologists. The accounts of the birth of Didelphys virginiana, as detailed above, and of Macropus rufus, as reported by Mr. Goerling, are seen to be in perfect agreement on the one essential point, namely, that the young reach the pouch and find the teat by their own efforts and entirely without the assistance of the mother. It would seem, therefore, that this will be found to hold universally among the numerous species of the Mar- supialia. The following are Mr. Goerling’s notes dated Decem- ber 19, 1912: THE BIRTH OF THE KANGAROO? The question of how the young kangaroo comes into the pouch has long been looked upon as answered. According to observations made, the young is born and placed on the pap by its mother, and this view has been accepted by zoologists. On the 25th of February, 1906, I had the good fortune to make the most interesting and astounding observation. I had a number of Macropus rufus and M. cervinus in my possession, caged in various- sized cages. On the morning of the above mentioned date I was attracted by the peculiar behavior of a female M. rufus. She refused the feed placed before her; and on seeing blood marks in the cage, I 8’ The italics are mine. 260 CARL G. HARTMAN came to the conclusion that the animal had just given birth to a young one. She was sitting in that resting position in which kangaroos can often be seen. The tail passed forward through the legs, thus she was sitting almost entirely on the thick part of her tail. She took no notice of my presence, although not more than three weeks in captivity, and was busy licking and cleaning herself. Presently she lifted her head, when I was astonished to see a young kangaroo clinging to the long fur about four inches below the opening of the pouch. It moved about slowly, very slowly, through the fur upwards, using the arms in its progress, and continually moving the head from side to side, thus assisting the upward movement. Nearly 30 minutes were required by the little wanderer to reach the top of the pouch, the last end in a semicircle. During the whole of this time the mother paid no attention to her offspring, offering no assistance, and leaving it en- tirely to its own exertions. She then became restless; and not wishi to disturb her, I moved a short distance away, when she at once st: to feed. A little later I paid another visit to her cage. She was sitting upright, the young one had disappeared, but the fur was still bearing evidence of the struggle, a plain visible track leading to and ending on the top of the pouch. Now I had the explanation of a previous observation, but which I misconstrued at the time. I had a female Macropus woodwardi— Woodward’s kangaroo—in captivity; and noticing blood stains in the cage, I believed the animal was hurt. I then noticed just such a young kangaroo clinging to the fur below the pouch, and thought the mother by restless movements had dislodged it. My observation of the 25th of February, 1906, proves that the new born kangaroo has to look after its own safety and reach the pouch without the mother’s assistance. The arms of the new born kangaroo are strongly developed, the small hands open and close like a cat’s paw, and by these strong little arms and hands the young one is enabled to labour its way to the pouch, the place of safety and nourishment. The question now presents itself, how can the young, with such a hard and firmly closed mouth, attach itself to the pap? I am convinced that at the time of birth the mouth has a wider opening and is perhaps more elastic than such specimens possess which are found in the pouch of the mother. Once a young kangaroo is removed from the pap, it is unable to reattach itself. As concluding proof that all newly born marsupials must reach the pouch by their own exertions, I mention that bandicoots, native cats and those very smallest of marsupials, the pouched mice, have the opening of the pouch in a reversed position to the kangaroos and phalangers. I had once in my possession a very small specimen of pouched mouse, having ten young ones in the pouch, each one not bigger than a grain of wheat. Only through the opening of the pouch being reversed are these smallest of born mammals enabled to reach it with safety and without much exertion. DEVELOPMENT OF THE OPOSSUM 261 LITERATURE CITED Hartman, Cart G. 1919 Studies in the development of the opossum (Didel- phys virginiana L.). Parts III and IV. Jour. Morph., vol. 32, no. 1, pp. 1-140. Hitt, J. P. 1895 Preliminary note on the occurrence of a placental connection in Parameles obesula, and on the foetal membranes of certain macro- pods. Proce. Linn. Soc., New South Wales, vol. 10 (2nd ser.), part 4. 1897 The placentation of parameles (Contributions to the embryol- ogy of the Marsupialia I). Quart Jour. Micr. Sci., vol. 40, pp. 385-42. 1899, 1900 Contributions to the morphology and development of the female urogenital organs in the Marsupialia, no. 1. On the female urogenital organs in Parameles, with an account of the phenomena of parturition. Proc. Linn. Soc. N.S. Wales, vol. 24, pp. 42-82. Part I, March 29; nos. 2-5, id., vol. 25, pp. 519-532. 1900 Contributions to the embryology of the Marsupialia. Quart. Jour. Micr. Sci., vol. 43, pp. 1-22. 1900 On the foetal membranes, placentation and parturition of the native cat (Dasyurus viverrinus). Anat. Anz., Bd. 18, s. 364-373. Hitt anp O’DonocuvuEe 1913 The reproductive cycle in the marsupial Dasy- urus viverrinus. Quart. Jour. Micr. Sci., vol. 59. Meies, Dr. Cuartes D. 1847 Reproduction of Didelphys virginiana. Proc. Am. Philosophical Soc., Philadelphia, vol. 4, pp. 327-330. Micuet, Dr. Mippteton 1850 Researches on the generation and development of the opossum. Proc. Am. Assn. Ady. Sci., vol. 3, Charleston, S. C. Osporn, H. F. 1888 The foetal membranes of the marsupials: the yolk sac placenta in Didelphys. Jour. Morph., vol. 1, pp. 373-382. Owen, Ricnarp 1868 Anatomy of vertebrates, vol. 1, p. 682. SeLENKA, E. 1887 Studien ueber Entwicklungsgeschichte der Thiere. IV (1 and 2), Das Opossum (Didelphys virginiana). Wiesbaden. Stockarp, CHARLES R., aNpD PapanicoLaou, Greorce N. 1917 The existence of a typical oestrous cycle in the guinea-pig with a study of its histo- logical and physiological changes. Am. Jour. Anat., vol. 22, pp. 225- 265. Resumen por el autor, Frank Charles Mann. Clinica Mayo, Rochester, Minnesota. Pancreas accesorio. En el presente trabajo se describen dos pdncreas accesorios hallados en perros. En uno de los casos la glaindula aberrante estaba situada a corta distancia distal del ligamento de Treitz, en la insercién mesentérica del yeyuno. La glindula presentaba forma triangular, midiendo 27 « 20 x 15mm. _ Posefa un con- ducto definido que desembocaba en el yeyuno. Su estructura histol6gica corresponde a Ja del tejido pancredtico normal, pero existe una cantidad relativamente pequefa de tejido insular, y los islotes son muy pequefos. La segunda glindula aberrante estaba situada en la pared del duodeno, a corta distancia de la entrada del conducto pancre- itico menor. Presentaba forma de disco y media 5 X 3 mm. Su estructura histolégica revela la presencia de acini y conductos normales, pero hay una ausencia casi completa de tejido insular. _ En este tiltimo caso es interesante la estrecha relacién entre el tejido pancrestico y la musculatura lisa de la pared duodenal. Translation by José F. Nonidez Cornell Medical College. New York AUTHOR'S ABSTRACT OF THIS PAPER ISSUED BY THE BIBLIOGRAPHIC SERVICE, SEPTEMBER 13 ACCESSORY PANCREAS IN THE DOG F, C. MANN Assistant Professor of Experimental Surgery and Pathology, Mayo Foundation (Graduate School, University of Minnesota), Rochester, Minnesota FIVE FIGURES Many cases of an accessory pancreas in man have been reported. At various times the separate reports have been collected (Opie, Ruediger, Warthin, Wiedman). An accessory pancreas has been found in the wall of the stomach, duodenum, jejunum, and ileum; in a diverticulum of the stomach, jejunum, and ileum; in Meckel’s diverticulum, umbilical fistula, mesenteric fat, great omentum, hilum of the spleen, and capsule of the spleen. In some cases the accessory glands have been consid- ered significant clinically in relation to atresia of some portion of the gastro-intestinal canal, obstruction, intussusception, pan- creatitis, and malignancy. From the embryologie standpoint the accessory pancreas has attracted considerable attention and study. The fact that the pancreas arises from two buds and the cells of origin are somewhat scattered seems at least partially to explain the development of accessory pancreatic tissue. There are few reports of'an accessory pancreas in species other than man, although some species are believed normally to have separate pancreatic tissue in the wall of the stomach or duo- denum, and the possibilities of its embryologic development in other species are certainly as great as those in man. No reports of an accessory pancreas in the dog were found in the literature. During two experimental operations on dogs in our laboratory two aberrant pancreatic glands were found. The account of the finding and the description of the two glands follows: Dog D 93 (experiment 249-19), an adult mongrel bull, weigh- ing 11.7 kg., was being operated on April 30, 1919, by Doc- 263 264 F. C. MANN tor McQuay for the purpose of developing the technic in some gastro-intestinal operations. While I was demonstrating a method of finding the first portion of the jejunum in the dog, I noted what appeared to be an accessory pancreas just below the ligament of Tritz. Since I was not aseptically prepared to oper- ate at the time, the exact nature of the gland was not deter- mined. The proposed gastro-enterostomy was abandoned, how- ever, and the left ureter was sectioned and anastomosed and the gall bladder removed by Doctor McQuay. The animal quickly recovered from the operation and gained in weight. July 8, 1919, I explored the animal for the purpose of definitely determining the presence of an aberrant gland (experiment 443— 19). The tissue was found to be an undoubted accessory pan- creas. Some measurements of the size and position of the gland were taken. At necropsy these were found to be approxi- mately correct. One small lobule, 4 by 2 by 1 mm., of the accessory pancreas was removed and fixed in neutral formalin- Zenker. The major pancreas was examined and found to be normal; one small lobule of it was also removed. Microscopic examination of these specimens showed both to be normal pan- creatic tissue. The animal was kept under observation, as it was planned to study the carbohydrate tolerance and then gradually remove the major pancreas in order to determine whether or not the accessory gland would take care of the carbohydrate metabolism. The animal was pugnacious, and March 5, 1920, was killed in a fight. The necropsy (107-20) was performed shortly after death. All tissues were well preserved. The site of the accessory pancreas was carefully examined. It was located 32 em. from the pylorus, 11 cm. below the upper attachment of the ligament of Tritz and 5 em. below its lower attachment. The gland was roughly tri- angular, with the small side of the triangle attached quite firmly to the jejunum. It measured 27 mm. along the greater side of the triangle, 20 mm. along the opposite side, and 15 mm. across the small side attached to the jejunum. It was 6 mm. thick. It appeared to be composed of perfectly normal pancreatic tis- ACCESSORY PANCREAS IN THE DOG 265 sue. A small duct, extending from the middle of the side at- tached to the jejunum, passed through the jejunal wall. This duct measured 2 mm. in diameter and 5 mm.in length. On the jejunal side the duct emptied into the lumen of the intestine through a small opening. Accessory pancreas Fig. 1 Diagram showing the relative position of the accessory pancreas of dog D 93. The major pancreas was large, weighing 45 gm. The animal was found to be normal except for a small lymphoma in the spleen, measuring 6 mm. in diameter. Microscopic examination of many sections of the accessory pancreas showed it to be composed of normal pancreatic tissue. The acini appeared perfectly normal. A large number of islands 266 F. C. MANN were scattered throughout the gland; it was noticed, however, that the islands were very small. In most instances not more than a dozen island cells were found in one group in a section. In comparison with the islands of the major pancreas they ap- peared very small indeed. Other than this decrease in island tissue and particularly in the size of the islands, no difference Fig. 2 Drawing of the accessory pancreas in its relation to the jejunum and the mesentery in dog D 93. was noted between the major pancreas and the accessory gland (figs. 1 to 4). Dog D 563 (experiment 200-20), a mongrel black and white hound, weighing 20.4 kg., was operated on March 26, 1920, for the purpose of making an Eck fistula. On pulling up the duo- denum an accessory pancreas was found 6 cm. from the pylorus on the right side of the duodenal wall, and 3 mm. above the entrance of the minor pancreatic duct into the duodenal wall, making it about 0.5 em. from the mesenterie border on the right side. The accessory gland was disk-shaped, 5 mm. in diameter, Fig. 3 Photomicrograph of the largest island found after a search through many sections of the accessory pancreas of dog D 93. It is normal, but small. 250. Fig. 4 Photomicrograph of one of the average-sized islands of the major pancreas of dog D 93. Compare with figure 3. 250. Fig.5 Photomicrograph of section of accessory pancreas of dog D563. Note the absence of island tissue and the intimate relation of pancreatic and smooth muscle tissue. 75. 268 F. C. MANN and 3 mm. thick. It was covered completely with serosa and imbedded in the muscularis, but was quite easily dissected out. It was impossible to determine grossly whether or not a duct connected it with the duodenum. The tissue appeared to be perfectly normal. A specimen was excised and fixed in formalin, and a specimen taken from the major pancreas just below the accessory gland was also fixed in formalin. On microscopic examination the major pancreas was found to be normal, and several sections of the accessory gland showed this also to be normal pancreatic tissue. Very little island tissue was found. Scattered in various parts of the section were groups of a few, seldom more than six, of what appeared to be island cells. The gland had well-developed ducts; undoubtedly a duct connected it with the lumen of the intestine. The pancreatic tissue and smooth muscle tissue were intimately associated; prolongations of one dipped, finger-like, into the other (fig. 5). BIBLIOGRAPHY Opie, BE. L. 1903 The anatomy of the pancreas. Bull. Johns Hopkins Hosp., vol. 14, pp. 229-232. Rvuepicer, G. A. 1903 Accessory pancreas. Jour. Am. Med. Assn., vol. 11, pp. 1059-1062. Warruin, A.S. 1904 Two eases of accessory pancreas (omentum and stomach). Physician and Surgeon, vol. 26, pp. 337-350. Werpman, F. D. 1913 Aberrant pancreas in the splenic capsule. Anat. Rec., vol. 7, pp. 133-139. Hii \% Wied! : met TAR ' Res Wier Son a ID us 7 Heh | ‘ATOMICAL RECORD, VOL, 19, No. 5 Resumen por el autor, H. L. Wieman. Universidad de Cincinnati. Observaciones relativas al desarrollo temprano de la glindula suprarrenal humana. Embrién de 9 mm. 1. Las crestas suprarrenales se extienden posteriormente desde las membranas pleuroperitoneales hasta las crestas genitales. 2. El tinico indicio de vascularizacién del tejido suprarrenal est& representado por algun corte transverso de un capilar. 3. En la regién suprarrenal los ramos comu- nicantes se extienden ventralmente mas alli de los ganglios prevertebrales del simpdtico, en forma de fibras nerviosas en apariencia desprovistas de células nerviosas. 4. Las células germinales extraregionales se presentan diseminadas en las proximidades de las crestas genitales. Embrién de 12 mm. Las gldndulas suprarrenales estén claramente separadas de los tejidos que las rodean. 2. La region central de la glindula es una red muy vascularizada, cuyos vasos sanguineos poseen paredes endoteliales bien distintas. 3. El lado medio de cada glindula esta en fntimo contacto con la prolongacién ventral del ramo comunicante y masas de células — ganglionares. Algunas‘de estas aparecen entre las fibras de la porci6n distal del ramo, a lo largo del cual parecen emigrar desde los plexos celiacos y viscerales. Translation by José F. Nonidez Cornell Medical College, New York AUTHOR’S ABSTRACT OF THIS PAPER ISSUED BY THE BIBLIOGRAPHIC SERVICE, SEPTEMBER 13 OBSERVATIONS IN CONNECTION WITH THE EARLY DEVELOPMENT OF THE HUMAN SUPRARENAL GLAND H. L. WIEMAN Zoological Laboratory, University of Cincinnati TWO PLATES (NINE FIGURES) The purpose of this contribution is to call attention to certain details in connection with the development of the human supra- renal gland, because they happen to be clearly illustrated in the material at hand. This material consists of two human embryos, nos. | and 4 of the author’s collection, which were obtained some years ago, freshly killed and fixed, from Drs. H. L. Woodward and Charles Goosmann, of Cincinnati. No. 1 had been killed in a bichromate-acetic mixture, and no. 4 in Bouin’s solution. The former measured 9 mm., crown-breech, and the latter 12 mm. Both measurements were made in 85 per cent alcohol after fixation, so that the sizes of the living embryos were some- what larger than these figures. The embryos were embedded in paraffin, cut into serial sections of 10 » thickness, and stained on the slide with Delafield haematoxylin and orange G according to the method of Morris (’09). Mitotic figures abound in both embryos, but the fixation is somewhat better in no. 1. OBSERVATIONS Embryo no. 1, 9 mm. The suprarenal glands are not recog- nizable as distinct organs, but consist of a thickening in the mesenchyme on either side of the root of the mesentery, forming a pair of broad ridges projecting into the body cavity from the dorsal body wall. Anteriorly these suprarenal ridges are continu- ous with the dorsal portions of the pleuroperitoneal membranes, while posteriorly they blend with the genital ridges. Laterally 269 270 H. L. WIEMAN each is separated from the mesonephros by a distinct groove (fig. 1). Occasionally a transverse section of a blood capillary can be seen in the center of each ridge, the beginning no doubt of the central vein of the adult organ. The ridges are made up of mesenchyme which shows no evi- dence of differentiation. The ramus communicans divides into two at the level of the sympathetic ganglion where one of the branches terminates, the other passing ventralward into the mesenchyme. The cells composing the sympathetic ganglia stain more deeply than the surrounding cells, but beyond this they show no appreciable differentiation. The ganglia lie on either side of the aorta somewhat dorsal to it. The nerve strands (axis cylinders?) are easily distinguished and followed, owing to the fact that they stain readily with orange G. The ventral branch of the ramus communicans, which is really the direct ventral continuation of the latter, loses itself in the mesenchyme of the suprarenal region. It seems to be unaccompanied by nerve cells (fig. 3). From the picture one gets the impression that the nerve fibers are pushing their way through the mesen- chyme, blazing, as it were, a track along which the ganglion cells are to follow later. In the posterior part of the suprarenal ridge, the genital ridge, the subepithelial region of the mesonephros, and in the mesentery, one finds large cells with clear cytoplasm and standing out dis- tinctly from all cells (fig. 3, 4, 5). These I take to be germ cells (primary genital cells). Their wide extraregional distribution indicates that these cells undergo a rather extensive migration before reaching the germinal epithelium. This of course is in keeping with what is known about the early development of germ cells in other vertebrates. ; Embryo no. 4,12 mm. ‘The suprarenal glands in this specimen are distinctly marked off from the surrounding tissues (fig. 2). Each one lies with its dorsal surface against the pleuroperitoneal cushion, while in close contact with its median side are bundles of nerve fibers and ganglionic clumps. Near the ventral border, as shown in figure 2, some nervous tissue is pushed into the sub- stance of the gland, but only to a very slight extent, definite DEVELOPMENT OF HUMAN SUPRARENAL GLAND 271 immigration, according to other authors, not taking place until a much later period. The prevertebral sympathetic ganglion is now a very distinct mass of cells clearly differentiated from the mesenchyme. Its relation to the ramus communicans is somewhat different from that described for the 9-mm. embryo. There is no longer any evidence of a branching in the ramus communicans at the level of the ganglion, the latter lying more directly in the path of the ramus. The ventral extension of the ramus (fig. 1) now passes directly ventralward from the ganglion (fig 2, v.r.). Among the nerve fibers of the ventral extension of the ramus can be seen two kinds of cells: 1) those distinguished by a long narrow outline with nucleus of the same shape, which are probably sheath cells and, 2) large irregular cells with yellowish cytoplasm drawn out into processes and possessing rounded nuclei. The latter are un- doubtedly migrating nerve cells (fig. 7). They are larger and differ otherwise in their appearance from the nerve cells‘found in the prevertebral ganglia (fig. 6), but are practically identical with the large nerve cells partially embedded in the ventral bor- der of the suprarenal gland (figs. 2, 8). Comparing the pictures presented by figures 1 and 2 it would seem that in the latter stage the nerve cells are in the actual process of migrating ven- tralward along the paths marked out by the nerve fibers, which alone are present in the former stage. If some of these migrating nerve cells are destined to enter the gland to form its chromaffin tissue and others to pass on to form the ganglia of the coeliac plexus, there is no way in the preparations at hand of distin- guishing the two kinds. According to Souilé (’03), the penetra- tion of the cortical portion of the suprarenal by the parasympa- thetic cells commences at the 19-mm. stage, which is of course considerably older than the one dealt with here. The cells of the gland itself are arranged in the form of a branch- ing network penetrated with blood-vessels, and resembling the zona reticularis of the adult organ. A distinct endothelium forms the walls of the capillaries (fig. 9). The only other indication of differentiation in the gland is the ingrowing of connective- tissue trabeculae at the periphery. to ~J bo H. L. WIEMAN DISCUSSION His, Jun. (91), deseribed a preliminary nerve-fiber framework laid out in the form of rami communicantes, along which the sym- pathetic cells wander to form the ganglia. Streeter (Keibel and Mall, v. 2, p. 149) states that in human embryos the migrating cells can be recognized in advance of the loose strands of the tip of the growing nerve which extend through the mesenchyme toward the aorta, and that by the time a well-defined nerve trunk is established, the sympathetic cells have already completed that part of their migration, and the cells then found on the nerve trunk are sheath cells only. In the 9-mm. embryo under discussion the nerve fibers forming the ventral extension of the ramus communicans beyond the sympathetic ganglia (fig. 1) may have been preceded by amigra- tion of ganglion cells through the mesenchyme, but my prepara- tions do not show nerve cells either among the fibers or at their distal endls (fig. 3). On the other hand, in the 12-mm. embryo the cells found scattered along the course of the fibers are un- doubtedly nerve cells rather than sheath cells. I am therefore inclined to believe that some at least of the ganglia migrate to their final location along paths formed of nerve fibers. The well-known work of Harrison (’06) which shows very conclusively that ganglion cells of amphibian larvae develop axis cylinders as outgrowths of the cell body, strengthens my conviction that the nerve fibers forming the pathway develop originally as out- growths from cells located in the cord. Whether the nerve cells subsequently found among the nerve fibers come directly from the spinal ganglia or from the prevertebral ganglia is another question. I can only say that the migrating nerve cells are larger and differ in outline from those found in the prevertebral ganglia. As has been noted above, Soulié (’03) states that the penetra- tion of the parasympathetic cells into the cortical portion of the suprarenal gland commences at the 19-mm. stage. Zuckerkandl (Keibel and Mall, v. 2, p. 173) states that the elements of the migrating cell masses, which are entirely or for the most part chromaffin-forming cells, are sharply distinguished from the DEVELOPMENT OF HUMAN SUPRARENAL GLAND 273 neighboring cortical cells by their smallness and intense stain. In my preparations one cannot say with certainty whether such cells are present or not. Deeply staiming cells occur bordering the nerve strands and the ganglionic masses, and these may represent the chromaffin cells, but if so they are sharply defined from the nerve cells and are more distinctly epithelial in character. Zuckerkand| (Keibel and Mall, v. 2, p. 171) found that the suprarenal glands are already vascularized in a 9-mm. embryo, whereas in my specimen of this age the only indication of vas- cularization is the occasional appearance in the suprarenal ridges of a cross-section of a blood capillary, which simply means that my embryo is younger than his, though both are the same length. In the 12-mm. embryo of my collection delicate endothelial capillaries form a very rich vascular network mvolving prac- tically all of the gland except the cortical region. The central vein is not visible. Hoffmann. (93) and others have shown that the primordial germ cells are distinct from the elements making up the germinal epithelium of the gonad and that they exist a long time before the appearance of the latter. More recently, Swift (14) has traced the history of the primordial germ cells of the chick from their origin in a specialized region of the germ-wall entoderm just at the margin of the area pellucida. These cells are carried by their own movement and later by that of the blood to all parts of the embryo and vascular area until in embryos of twenty- six to twenty-nine somites they are found in the splanchnic meso- derm near the radix mesenterii: With the formation of the gonad they gradually pass to that organ. Fuss (’11) describes extra- regional germ cells in a human embryo aged four weeks. He finds them in the mesentery directly under the peritoneum, but not in the germinal epithelium. According to his description, they are large cells of rounded outline, with clear cytoplasm and distinct nucleus. The cells measure 19 to 20 » in diameter and the nuclei 12.75 xz. In my 9-mm. embryo, which is somewhat older than the one studied by Fuss, I have found cells resembling the one pictured 274 H. L. WIEMAN by Fuss in his figure and corresponding in every way to those described in his text, except that the measurements I have made are somewhat less than his. Likewise I find the distribution of these primitive germ cells to be somewhat wider than he found, and in my preparations some of the cells have approached very close to the germinal epithelium (fig. 4). The 12-mm. embryo did not prove favorable for the study of these cells, so that I have no data on the range of distribution at this later stage. My observations on the 9-mm. embryo corroborate the statements of Fuss, which indicates that the germ cells of man like those of other vertebrates are characterized by period of migration in the early part of their history. SUMMARY 9-mm. embryo 1. The suprarenal ridges extend from the pleuroperitoneal membranes posteriorly to the genital ridges. 2. The only indication of vascularization in the suprarenal tissue consists in an occasional cross-section of a capillary. 3. In the suprarenal region the rami communicantes extend ventrally beyond the prevertebral sympathetic ganglia as nerve fibers apparently free of nerve cells. 4. Extraregional germ cells are found widely scattered 1 in the neighborhood of the genital ridges. 12-mm. embryo 1. The suprarenal glands are distinctly marked off from sur- rounding tissues. 2. The central region of the gland is in the form of a network, and is highly vascular, the blood-vessels having distinct endo- thelial walls. 3. The median side of each gland is in close contact with the ventral prolongation of the ramus communicans and masses of ganglia cells. Some of the latter are found among the fibers of the distal part of the ramus along which they seem to be migrating to form the coeliac and visceral plexuses. ba | on DEVELOPMENT OF HUMAN SUPRARENAL GLAND 2 LITERATURE CITED Fuss, A. 1911 Ueber extraregionare Geschlechtszellen bei einen menschlichen Embryo von vier Wochen. Anat. Anz., Bd. 39. Harrison, R.G. 1906 Further experiments on the development of peripheral nerves. Am. Jour. Anat., vol. 5. His, W., son. 1891 Die Entwicklung des Herznervensystems bei Wirbeltiere. Abh. d. math.-phys. KI]. d. Kgl. Sachs. Ges. d. Wiss., Bd. 18. Horrmann, C. K. 1893 Etude sur le développement de lappareil urogenital des oiseaux. Verh. d. Kgl. Akad. vy. Wetenschoppen. Amsterdam, vol. 1. KeErIBeL AND Matt 1912 Manual of human embryology. Philadelphia. Morris, J. T. 1909 A note on orange-G counterstaining suggesting a useful method in the management of embryonic tissue. Anat. Rec., vol. 3. Sounré, A. H. 1903 Recherches sur le développement des capsules surrénales. Journ. de l’Anat. et de la Physiol., vol. 39. Swirt, C.H. 1914 Origin and early history of the primordial germ cells in the chick. Am. Jour. Anat., vol. 15. DESCRIPTION OF FIGURES Figs. 1 and 2 are camera drawings made at table level with Zeiss ocular 2- and 16-mm. objective. The remaining figures were made with Zeiss ocular 4- and 2-mm. objective. All figures have been somewhat reduced in reproduction. ABBREVIATIONS USED IN FIGURES b.v., blood-vessel p.c., pleuroperitoneal cushion e.c., endothelial cell s.g., prevertebral sympathetic gan- g.c., primordial germ cell glion g.r., germinal ridge s.r., suprarenal ridge n.c., nerve cell v.r., ventral continuation of the ramus n.f., nerve fiber communicans PLATE 1 EXPLANATION OF FIGURES 1 Transverse section through suprarenal region of 9-mm. embryo. 2 Transverse section through suprarenal region of 12-mm. embryo. 3 Enlargement of portion of ventral continuation of the ramus communicans of figure 1. 4 Enlargement of portion of germinal ridge of figure 1, showing a primordial germ cell near the germinal epithelium. ; 5 Enlargement of portion of subepithelial portion of the suprarenal ridge of figure 1 also showing a primordial germ cell. y | ; DEVELOPMENT OF HUMAN SUPRARENAL GLAND PLATE 1 H. L. WIEMAN PLATE 2 EXPLANATION OF FIGURES 6 Enlargement of portion of the prevertebral ganglion of figure 2. 7 Enlargement of the ventral continuation of the ramus communicans of figure 2. 8 Enlargement of the ganglionic mass embedded in the ventral border of the suprarenal gland of figure 2. ; 9 Enlargement of the central portion of the suprarenal gland of figure 2, showing the capillary structure. PLATE 2 DEVELOPMENT OF HUMAN SUPRARENAL GLAND 279 Resumen por los autores, George B. Wislocki y Tracy Jackson. Putnam. Escuela Médica Harvard, Boston. Nota sobre la anatomfa de las dreas postrematicas. Las areas postremiiticas son masas de tejido situadas en el extremo caudal del cuarto ventriculo; estén compuestas de células de neuroglia y est’in muy vascularizadas. Al fusionarse forman el techo del canal central de la médula. Estén cubiertas de delicadas células ependimarias aplanadas, que difieren del epitelio que tapiza interiormente el resto del cuarto ventriculo. En las is dintdle cane are taite ea ps Pee ee 3 Seed Panchromaung oc os. 55 anc sen sc ce. peeicasine suceea tare detas aetna 3 Wratten Me, ctcckctac duke sede e ope s be ocy ai ran een tide tee OnE Sena 1 Slow plates for special work Cramer’a'Contrast’ (green libel)... <5). 35 122 5% sans ce Dentoeeenemeen 6 SeGGP TO GRAS. 3 2x) oiaslz sie 0105 i> - sme wale’ be wate nets aiete ee ee 12 Lanteamalide, Mastmaninns ct. «vs. al ica + cee moeaetereiok aera 60 Ganternshide; Impermlispecisl...-...... 0c... gute ese eee aan 36 Banternslidie, Seed soo se cc - ssc vcs otc eis ener nts «Cette Seana 36 Lanternslide;Standard) (blue label: 5... 9200 Sop ceee deen eee 4 Lanternslide; Standard, white label. ....<:.:<0<:s:0«0% «s+ sla saules SEE 18 Plates for color photography Lumiere’s Autochrome with Lumiere’s rayfilter..................... 72 Hess-Eves HiblOGK. 2. ces ves oun ates. ove ceneale Dagan ere sae eece Meta 60 Paget direct colour, with screen and rayfilter...............00..000: 24 As in the preparation of the magnification table, so in the preparation of the table of exposure factors for the given magni- fications one cannot be guided by the simple rule that exposure stands in direct ratio to the square of magnification. This rule is of great help in preparing the table for a single system, where nothing but the ocular or the extension of the bellows is changed. But when it comes to the use of another objective, two new factors must be taken into account. It is well known that exposure var- ies as of the objective, and this formula does not apply 1 — (N. A.)? to oil-immersion objectives. Moreover, it is desirable to use the optimum position for the substage condenser and this position, as explained in the paragraph on the lighting system is a different one for every objective. The best way to proceed is, therefore, to ascertain by actual exposure the time of correct exposure for a given magnification for each objective at the optimum position of the substage. Once these are obtained the correct exposures for all other magnifica- tions for each system may be calculated. For example, if you have found that the correct exposure for an Orthonon plate at STANDARDIZED MICROPHOTOGRA PHY 299 100-diameter magnification obtained by the use of an objective apochromate 16 mm. in combination with a projection ocular 2 and optimum position of the substage condenser at mark 5 of your scale is 0.04 second, then the exposure for the same combi- nation at 400-diameter magnification, even if that magnification has been obtained by the use of ocular 4, will be 0.64 second. Unfortunately, it is by no means easy to decide what is a cor- rect exposure. To ascertain it as nearly as possible it is impera- tive to use time and temperature development and fractional exposure. My experiments were made with the following de- veloper which has many good qualities, does not stain the fingers or the plate, but must be used fresh in every experiment, since the time of development increases considerably with the use of the developer. Pyro-acetone developer Solution A IVER OTE estes = fey fat sse foisted, forchers ajave. ate hats Pereret Tesesisle ciel Sass! eiels.e tyaia’s 500 ce CORE TRO (s | cr onneGnnioO I CIODE DOOSGp OcCcE SO SCREOCP rca bere 1 gram AUTON AUTO ASN CLC ae MeyARTe atehe vers. a= ih evar otavctaristveve?o sist sie, saforaisiolels 30 grams Solution B WIGIGTS a Sab ade COCR CC ORO OCT OOURE 166 COU DS rOOEOOOEEEOEre 1000 ce DOGFUN SUD HIGEs | ALY Sessa ectetet ers cieteiels are aie siete a sinteleicieleare 120 grams RUPERT eta crc veyerascvcvasoi of eveh as o1e clelCinfavarsicreieie[cis/eisiswala areteis:« e-sjelave.aisi6,aie 120 ce SOLA LLO TINA tose ats crare vic ote cicte remeron ta aroha aialals ai cisterdjo.owlisaea 15 ee. SOMEnIOUE EMS > eisrcnite eis seteeitetes Meee > ies mom Ae Sisto ached 30 ce. PNG COTAC rots cath cy puck seb ove x Perch Pera cu erate rine cla ray ater siejerolalh s,ciesesaiwieys 6 ce. If the mixture has a temperature of about 18.3 to 18.8°C. (65 to 66° F.), then the image of a correctly exposed plate will appear in fifteen seconds and the development will be completed in six minutes from the time the plate was immersed in the developer. Fractional exposure consists in making four different exposures on the same plate in such a manner that each following exposure is twice as long as the preceding one. These exposures may be represented as a, 2a, 4a, 8a. To make such an exposure, the 300 ALEXANDER PETRUNKEVITCH slide of the plate-holder must be marked with three parallel lines dividing the plate in four quarters. The slide is opened and the plate is exposed a seconds (or fractions of a second). Now the slide is moved in one quarter and the plate is exposed again a seconds (or fractions of asecond). When moved in two quarters the exposure should be 2a and when the plate-holder is moved in three quarters the exposure should be 4a. The choice of an object to be photographed is also important. A stained section will not do and it is advisable to use a slide which will permit the use of both low- and high-power objectives. I have used the Diatome Arachnodiscus and a thin section of human bone. The time of the appearance of the four images in the developer will at once indicate which exposure is nearest to be the correct one. It is advisable to control the experiment by making another fractional exposure at a higher magnification. The completed exposure table will consist of as many vertical columns as there are objectives in the outfit, and for each of these columns the optimum position of the substage must be indicated at the top of the columns. A special column on the left of the table will contain all magnifications as accepted in the magnifi- cation table. HOW TO PREPARE A TABLE OF RAYFILTER-PLATE FACTORS The choice of rayfilters is not entirely a matter of taste. While one can use fluids in special containers, it is simpler and better to buy a set of dry rayfilters from a reliable firm with stated regions of light transmitted. Such filters are more permanent and easier to use. It is not advisable to make dry rayfilters in the laboratory unless the laboratory is provided with instruments which permit the preparation of identical rayfilters at any time in case of inadvertent damage, since a variation in the region or in the intensity of light transmitted would affect the exposure. At the Osborn Zoological Laboratory we have accepted as a standard equipment for all photographie work Cramer’s photo- m crographic rayfilters. There are ten of them and singly or in combination they transmit the following regions: STANDARDIZED MICROPHOTOGRAPHY 301 Heats = Benet Breer Sn. ch ea aventiaree A-6350 Otek; SSamh acy axes aetna 6920-5840 Pas AGE DCO USE eae A-6100 Weta Uaeha tos Seer stasenavacy Wee aos < 5900-5800 Naat fetes clete Rites tide, sae A-5850 On Ohta sete aac le = erat shalbtors A-7000 sc SNORCCIET ENRICO CE 1 A-5400 Le Ch ARTS ADSI RTCIGCE 6870-5525 BA elsiae bsletevreetens Sets A-5250 BET i ODO SNES so ce Mn ai « 5900-5660 Girecisitisacecliresiacyedecitis A-5100 Det atatataparabstnvora: wie aie is. othe ‘s 5900-5400 UU Gea p UOC GOR SO oT Erao 5800-5000 Qa Oh srs aterm ass heiveietercves e's 5530-5350 (ONG COTO NOE Rare erent 5200-3950 GateTha titeceelaristrecinvers cre 5900-5150 UB pee ee CCIE Ieee rete 5200-3500 GS ies stoke tastes satus cess 5350-5150 LOEB as tops aclscies Visual luminosity GOR rat mech ie osce ies 5600-5200 Te etraata xo fertaonstece (arses 5200-5000 Tao eric sa ce civietontere ees) DSOO-O LOO The Wratten ‘M’ filters transmit somewhat different regions, as shown in their booklet. If all plates were equally sensitive to the same regions of the spectrum, the same factors would apply for all makes. But experience shows that one brand of plate may be twice as rapid as another in daylight yet be considerably slower with a special rayfilter. Thus the Standard Orthonon is twice as rapid as Cramer’s Medium Iso in daylight, and four times as slow in green light in the region 5200-5000. When it comes to the use of red light, nothing but panchromatic plates can be used. The Wratten ‘M’ plate answers this purpose adm‘rably, but for or- ange, yellow, and blue light the Orthonon plate is preferable if for no other reason than greater ease and safety in handling it. For green light we use Cramer’s Iso Medium or Instantaneous Iso. To find the correct rayfilter-plate factors it is necessary to use the same slides as were used in the preparation of the table of exposure factors without rayfilter. Fractional exposure with a rayfilter will easily show how much the normal exposure must be prolonged to obtain the same results. A separate exposure ex- periment must be made for every rayfilter or combinations of rayfilters and plate. Thus was the following table of RP fac- tors obtained, but naturally it is good only for the Cramer ray- filters. 302 ALEXANDER PETRUNKEVITCH Table of R-P factors for use with Cramer's photomicrographic rayfilters and dry plates. The unit of comparison is the normal exposure for a standard Orthonon plate without rayfilter. The figures are good only when the light is an open arc CRAMER'S RAYFILTER, sino Om GOMBIRATION| yy TANDARD | WRATTEN M |rmanen's cpprowjonaupa'e pews i 250 2 30 3 500 * 15 4 30 50 5 15 6 10 7 60 8 15 15 9 10 10 5 10 3+4 600 15 4+5 30 447 1000 400 5+7 250 100 5+8 2000 600 250 6+7 100 6+8 1000 150 7+8 2000 500 250 Without rayfilter 1 1 2 1 THE CHOICE OF THE RAYFILTER COMBINATION The choice of a rayfilter will naturally depend upon the results to be attained. At times it may be desirable to get as much con- trast as possible regardless of the loss of detail, especially if some single structure should be shown clearly. In such cases a ray- filter which makes the structure appear black to the naked eye, i.e., arayfilter which absorbs all rays transmitted by the structure to be photographed, is the one that will give the best results. If the section has a counterstain, if for example the stain employed was haematoxylin-eosin, and it is desired to show only the strue- tures stained with haematoxylin, then an eosincolored rayfilter which will transmit all rays of that color may be used with ad- vantage. In the majority of cases, however, the photograph will be much more satisfactory, if the contrast is less, but the detail greater. To find the right combination that will answer STANDARDIZED MICROPHOTOGRAPHY 303 this purpose is not an easy matter. One may be helped by an examination of each staining fluid through a direct vision spec- troscope, but the final decision has to be derived from an actual exposure. It will be also found that an examination of the image on the screen with different rayfilters will be of great help. In case of doubt, two or three different combinations may be tried and the negatives compared. In the following table is given a list of the commonly employed stains and the best combinations of plate and rayfilter for each. CORRECT EXPOSURE The exposure factor multiplied by the R-P factor will give the correct exposure in seconds for the given combination of stain, rayfilter, objective, substage position, and magnification as indi- cated in the tables. If care is exercised not to overlook a single one of these conditions and to see to it that the source of light is also in its proper place, the only element unaccounted for re- mains the microscopic slide itself. The quality of the tissue, the intensity of the stain, the thickness of the section, play no -Inconsiderable part in the determination of the correct exposure. If the tables are prepared from a very thin and transparent sec- tion, the deviation in exposure of thick sections will be great. It is therefore advisable in standardizing the apparatus to use either ‘medium thick sections, or else to take the mean of two figures obtained from an exposure of a very thin and a very thick section under identical conditions. No satisfactory rules can be formulated in regard to the transparency factor of the * microscopic section, but the student will rapidly learn the neces- sary increase or reduction in the time of exposure. As a rule, correct exposure gives the best results. Under cir- cumstances, however, overexposure is desirable and even indis- pensable. Just as in a brilliantly sunlit room one obtains a much better picture of details if one gives long exposure and develops the plate with a restrainer, so in microphotography details may be brought out by overexposure when some parts of 304 ALEXANDER PETRUNKEVITCH Table showing the best combination of dry plate and rayfilter for stains in common use, spectral regions transmitted and the R-P factors : CRAMER'S STAIN PLATE Bare Lehto pe None Orthonon None | Entire x spectrum None Orthonon 10 Entire 5 spectrum Acid green+safranin Instant Iso 4+7 | 5900-5660 | 400 Orthonon 1000 Anilin blue Orthonon 4 A-5400 30 Medium Iso 50 Anilin blue+safranin : Orthonon 5 A-5250 15 Azur II Wratten M 3 A-5850 15 Orthonon 500 Bielschowsky’s silver Instant Iso 5+8 | 5530-5350 | 250 Orthonon 2000 Bismark brown Orthonon 8 5200-3950 15 Bleu de lion Instant Iso 4+7 | 5900-5660 | 400 Orthonon 1000 Carmalum Instant Iso 5+8 | 5530-5350 | 250 Medium Iso 600 Carmine (all stains, acid, alum, | Instant Iso 5+8 | 5530-5350 | 250 borax, para, picro, etc.) Medium Iso 600 Orthonon 2000. Erythrosin+cyanin Orthonon 7 5800-5000 60 Eosin Instant Iso 6+8 | 5350-5150 | 150 Orthonon 1000 Fuchsin Instant Iso 6+8 | 5350-5150 | 150 * | Orthonon «| 1000 Gentian violet Wratten M 3 A-5850 | 15 Orthonon 500 Gentian violet+safranin Medium Iso 5+7 | 5900-5400 | 100 Orthonon 250 Giemsa’s Instant Iso 4+7 | 5900-5660 | 400 . Orthonon 1000 Gold chloride Instant Iso 5+8 | 5530-5350 | 250 Medium Iso 600 Orthonon 2000 Hemalum Medium Iso 5+7 | 5900-5400 | 100 Orthonon 250 Haematoxylin (all stains Boehmer’s, | Medium Iso 5+7 | 5900-5400 | 100 Delafield, Ehrlich, iron, etc.) Orthonon 250 tel STANDARDIZED STAIN Haematoxylin+boraxcarmine, con- gored, eosin, erythrosin, orange G, picrocarmine, tetrabromfluor- escic acid Haematoxylin+safranine Indigo carmine Iodine green Iodine green+acid fuchsin Methy! green Methyl green+acid fuchsin Methyl! violet Methylen blue+eosin, Romanow- sky, Wasielewski, ete. Mallory’s Magdala red+anilin blue Nigrosin Orange C Picric acid Rose Béngal Safranin Safranin+acid green, light green Safranin+gentian violet, picric acid, waterblue Safranin+haematoxylin Silver impregnation Sudan IIT Tetrabromfluorescic acid Toludin blue+erythrosin Vesuvin Victoria blue - MICROPHOTOGRA PHY PLATE Medium Iso Orthonon Orthonon Wratten M Orthonon Wratten M Instant Iso Orthonon Wratten M Wratten M Wratten M Orthonon Instant Iso Orthonon Instant Iso Orthonon Medium Iso Orthonon Orthonon Orthonon Orthonon Instant Iso Orthonon Instant Iso Medium Iso Orthonon Instant Iso Orthonon Medium Iso Orthonon Orthonon Instant Iso Orthonon Instant Iso Orthonon Instant Iso Orthonon Instant Iso Orthonon Orthonon Wratten M Orthonon 305 CRAMER'S RAY- FILTER 5+7 SPECTRAL REGION 5900-5400 A-5250 A-5850 A-6350 5350-5150 A-6350 6920-5840 A-5850 5900-5660 5900-5660 5900-5400 A-5250 5200-8950 5200-3950 5350-5150 5200-5000 5900-5660 5900-5400 A-5250 5530-5350 5350-5150 5350-5150 5900-5660 5200-3950 A-5850 R-P FACTOR 306 ALEXANDER PETRUNKEVITCH a section are much more transparent than others. In overex- posing a plate it is advisable in such cases to know the exact ratio of overexposure as the restrainer should be used in strict conformity with that ratio. The pyro-acetone developer of the formula given above lends itself admirably to such work. I have made a series of experiments in which the correct exposure was first carefully ascertained for a given microscopic slide, and the exposure then increased twice, four times, eight times, six- teen times, thirty-two times, sixty-four times, one hundred twenty-eight, and two hundred fifty-six times. Measured quan- tities of potassium bromide were added to the developer and frac- tional exposure used to see the results more clearly. The plates were left six minutes in the developer. A similar series of plates was left seven minutes and a third eight minutes. The best negatives were noted and a fresh plate was exposed same length of time and developed in the same manner as a control. Thus several formulae were obtained, each giving excellent results for the given overexposure. Those who have seen my negative which was overexposed about 130 to 150 times and then developed with the restrainer agree that aside from its yellowish color one would never guess that the plate was overexposed. a. Pyro-acetone developer for plates overexposed 4 times: { Water2ad..2ai Je iteanciney ace. te ree ee 120 ce. Normal developer | Solution A...........2.c0ceeceeceeccceesees 15 ee. Solution. B saisek st... Mees Ogee eee 30 ce. UAGELONG GE sth 5 pote sieheperale eth «rae aetis Ari 6 ce. 10 per cent potassium bromide................. Sa ane 1 co: Develop 6 minutes at 65° F. b. Pyro-acetone developer for plates overexposed 8 times: Normal developer as above 10 per cen’ potassium Gromida eso. ss ss be ks s vies ame eee 2 ce. Develop 8 minutes at 65°F. c. Pyro-acetone developer for plates overexposed 16 times: Normal developer as above 10 per cent ‘potassium bromidGlyiys + <1 vec vucsices ue stscxes sedans 10 ee. Develop 8 minutes at 65°F. ' STANDARDIZED MICROPHOTOGRAPHY 307 d. Pyro-acetone developer for plates overexposed 32 times: Normal developer as above HOMER ICENtsPOUASSIUM DLOWMIGE 1.0). /5osnis:s.0.0 EARLIEST STAGES IN HUMAN CLAVICLE PLATE 2 FRANK BLAIR HANSON PLATE 3 EXPLANATION OF FIGURES “ ; 10 Photomicrograph of developing clavicle, showing two centers of ossifica- tion. This and the following three photomicrographs are introduced to show | several stages of the developing clavicle as it actually appears under the micro- — scope. Together with a large number of others, they constitute the basis for the _ schematic figures 4 to 9 and the conclusions reached in this paper. Series 240,, slide 26, sectionl. X29. Mall Collection, Carnegie Laboratory of Embryology. 11 Older stage than above. Outer half of clavicle fully ossified, pal lags in ossification process and more cartilage is present in this part. Ossifica- tion is ectochondrial. Series 460, slide 19, section 7. 29. Mall Collection, Carnegie Laboratory of Embryology. Cl, clavicle EARLIEST STAGES IN HUMAN CLAVICLE FRANK BLAIR HANSON wo PLATE 3 PLATE 4 fi EXPLANATION OF FIGURES ee eee ae | 12 The two parts of the clavicle are hosing to fuse, Series 1324, aide, section 6. 55. Mall Collection, Carnegie Laboratory of et ate 13 Photomicrograph of developing clavicle, showing acromial center of ossi- fication well established and inner center just beginning around the lower out- co side edge of clavicle, an ectochondrial ossification. Series 240, slide ‘ tionS. X48. Mall Collection, Carnegie Laboratory of Embryology. Cl, clavicle 324 EARLIEST STAGES IN HUMAN CLAVICLI PLATE 4 FRANK BLAIR HANSON Resumen por el autor, Frank Blair Hanson. Universidad Washington, Saint Louis. El problema del coracoides. Eel embrién del opossum americano, Didelphys virginiana posee un coracoides, que, lo mismo que en los monotremas, se extiende hasta el estern6n, uniéndose con él en un punto situado entre la clavicula y la primera costilla. Esta Ultima se atrofia y deja un pequeno proceso rudimentario, conocido en el adulto con el nombre de proceso coracoideo. A la parte descriptiva sigue una discusi6én de la homologia del proceso coracoideo del hombre, esforzindose el autor en demos- trar que el proceso coracoideo del hombre es el homélogo del precoracoides de los reptiles f6siles del Pérmico. Translation by José F. Nonidez Cornell Medical Collge, New York AUTHOR'S ABSTRACT OF THIS PAPER ISSUED BY THE BIBLIOGRAPHIC SERVICE, OCTOBER 4 THE PROBLEM OF THE CORACOID FRANK BLAIR HANSON Department of Zoology, Washington University, Saint Louis, Missouri TWO PLATES (SEVEN FIGURES) _ INTRODUCTION The phylogeny of the coracoid presents one of the most fasci- nating and elusive problems of vertebrate morphology. The literature is extensive. The number of conflicting theories and the confusion of the nomenclature is hardly paralleled in the history of any other vertebrate structure. This is due, in part, to its long history, occurring as it does in the Elasmobranchii and found in every group of animals from the dogfish up to man; also, in part, to the radical character of the modifications under- gone in the different groups through adaptations to structural and functional demands. A long history of structural changes in a region of progressive functional differentiation, and, com- plicated further by the presence of both dermal and cartilage bones, gives an ideal situation for exactly what has happened in regard to our knowledge of the coracoid. One is at times disposed to pigeon-hole this problem among the insolubles, or at least await patiently and in silence for the somewhat remote possibility of turning up some new evidence from paleontological specimens yet to be collected. However, this is one of those haunting problems that refuses to be pigeon-holed, and, once infected by its appeal, the investi- gator finds himself returning to i+ again and again. DIFFICULTIES OF THE NOMENCLATURE As indicated above, the \ menciature of the coracoidal ele- ments of the different groios is terribly involved and confusing. Different authors appl: ‘he same name to very different struc- tures, and again differen’ names to the same structure. 327 THE ANATOMICAL RECO! ©. you. 19, no. 6 328 FRANK BLAIR HANSON In reading the literature on the subject it is necessary, first of all, to ascertain just which element each author has in mind when using the terms metacoracoid, coracoid, epicoracoid, precoracoid, procoracoid, and subcoracoid. As an example of this, Cuvier in 1826 applied the term ‘epicoracoid’ to the anterior coracoidal ele- ment in monotremes. W. K. Parker and others use this same term in speaking of the cartilaginous element on the ventral ends of the coracoids in the frog, alligator, ete., while by Case, Williston and Gregory this same term is used to designate the unossified element found in some fossil reptiles anterior to the two ossified coracoids. A few remarks may clear up the matter somewhat. In the first place, the term ‘epicoracoid’ was first given to the anterior element in the monotremes, and by priority should be retained in this connection. The ventral median cartilages of the coracoids of the frog, alligator, etc., have no claim to this name except through the usage of Parker (67). These cartilages might better have the term ‘infracoracoid’ applied to them, which would be a suitable and descriptive term and would pair well with the corresponding dorsal cartilage, the sup: ascapula. Second, the term ‘subcoracoid’ may now be discarded. It was formerly applied to the small element on the anterior side of the glenoid fossa in man, and, as its name indicates, was thought to be a vestigial coracoid element. There is now general agreement (infra) that this small bone is a neomorph and not of phyloge- netic interest. This disposes of one term from the list Third, the terms ‘precoracoid’ and ‘procoracoid’ are synony- mous, some authors preferring one and some the other, while a few use them interchangeably. By pre- or pro-coracoid is under- stood the anterior of the two ossified elements of Permian rep- tiles, but not the most anterior of all, which is a cartilaginous epicoracoid (infra). Fourth, ‘metacoracoid’ is the name given by Williston to the most posterior coracoid of the Permian reptiles. Fifth, the simple term ‘coracoid’ has been so long applied to the coracoid process of man, that it must be retained in this ser- vice and its ancestry sought either in the metacoracoid or pre- coracoid of Permian fossils. : THE PROBLEM OF THE CORACOID 329 If Broom and Watson are correct in their contention that the metacoracoid of Permians is the homologue of the coracoid pro- cess of man, then the metacoracoid is the true coracoid. On the other hand, if the arguments set forth in this paper are valid, the precoracoid is the true coracoid of man. An examination of the shoulder-girdle of Moschops (fig. 5) will give the correct names of these coracoid elements and their relations to one another when all are present. THE MARSUPIAL CORACOID Broom (97, ’98, ’99, ’02, 712), in a series of papers on the shoulder-girdle of the Australian marsupials, has demonstrated that in all the genera studied by him the coracoid extends to and connects with the sternum during early developmental stages. This embryonic coracoid extends from the anterior part of the glenoid cavity to a position on the sternum between the clavicle and first costal cartilage. In the earliest stages there are no sutures between these parts (scapula, coracoid, sternum), but the whole is one continuous mesenchymatous and later precar- tilaginous mass. The adult marsupial has only a small rudimentary coracoid process (fig. 7) attached to the scapula, not relatively larger than in the higher mammals and man. The transition between the condition in the embryo and that in the adult form is, according to Broom, by a process of degeneration, beginning near the middle portion of the fetal coracoid. This progresses in each direction, completely destroying the sternal half, but only incompletely destroying the scapular half, leaving the well-known rudimentary coracoid process of the adult attached to the anterior side of the neck of the scapula. This embryonic coracoid of the marsupial has on its anterior border a ‘fan-shaped cellular element’ which does not participate in the glenoid and is of even shorter duration than the posterior element. Broom considers this anterior element to be an epi- coracoid and homologous to the element in the monotremes known by this name and having precisely the same shape, posi- tion, and relations. 330 FRANK BLAIR HANSON The posterior fetal coracoid of the marsupial has exactly the same position and relations to the scapula, clavicle, and sternum as has the posterior coracoid in monotremes, and the two are quite certainly homologous. It appears from this work of Broom that the embryonic shoulder- girdle of the Australian marsupial is identical with the adult girdle of the monotreme. I state this strongly at the outset because of the bearing it seems to have upon the whole question of the homology of these elements. In this identity is wrapped up one of the clues to the homology of the coracoid process of man. Formerly it was impossible to pass from the reptilian-like girdle of the monotremes, with its coracoid complete from scapula to sternum, up to the girdle of the adult marsupial, and higher mammals, with a mere rudimentary process attached to the scapula. The development of the marsupial, however, demon- states in the clearest manner how the coracoid process of the adult passes through a monotreme-like stage with a coracoid extending from sternum to scapula, and how by absorption and degeneration all is lost except the small process on the adult scapula. Since the work of Broom has an important bearing upon the solution of the long-vexed question of the phylogeny of the cora- coid process of man, the question may arise whether his observa- tions and interpretations are correct. Watson (’17), a very care- ful worker, has verified Broom’s results in at least one species of marsupial, Trichosurus. Watson made reconstructions in wax of the parts under discussion and showed that conditions were exactly as described by Broom. Recently I have had the opportunity! to examine several series of transverse and frontal sections of Didelphys virginiana, the American opossum, and have found that in our native mar- — supial as in his Australian relatives the coracoid is a solid bar of mesenchyme and later of young cartilage cells, extending with- out sutures from the scapula to a point on the sternum between the clavicle and first rib (figs. 1 and 2). ' My appreciation is hereby expressed to Dr. J. L. Bremer, of the Depart- ment of Anatomy of the Harvard Medical School, for the privilege of examining the marsupial slides in the Harvard Embryological Collection. THE PROBLEM OF THE CORACOID 331 In older stages the coracoid has parted company with the sternum, and that process of absorption, described by Broom for the species studied by him, has begun, which will eventually leave it in the adult but a mere finger-like projection on the anterior neck of the glenoid (fig. 7). Since the shoulder-girdle of the American opossum was found to be in all essential aspects the exact counterpart of the anterior girdle in its cousins of Australia, no detailed description is nec- essary here, and I may proceed at once to the discussion of the homology of the coracoid process of man. THE HOMOLOGY OF THE CORACOID Broom (’99) in describing the shoulder-girdle of a 17-mm. mammary fetus of the marsupial Trichosurus, says of the cora- coid that it is of ‘‘much the same absolute size as in the 14.8 mm. stage, and is thus considerably smaller relatively.’”” Broom’s work on many species of marsupials shows that as development proceeds the coracoid which once reached the sternum in the embryo and fetus is.in the adult only a small process attached to the scapula. I have observed much this same thing in higher mammals where the coracoid process is relatively much larger in the embry- onic stages than in the older fetal stages. Even in the pig, which in the adult has no coracoid process, a small coracoid is present in the embryo and diminishes in size with development. This is also strikingly true in the mouse and human embryos. Broom has demonstrated conclusively that the coracoid proc- ess of adult marsupials is a persisting rudiment of the coracoid which in the fetus extends from the scapula to the sternum. The coracoid of marsupials, therefore, is homologized definitely with the coracoid process of higher mammals and man on the one hand, and with the posterior of the two coracoid elements in the montremes, for in all their morphological relations the two coracoidal elements of the fetal marsupial can be compared directly with the two coracoids of the monotreme. Thus the homologies of the mammalian coracoid may be stated as follows: the anterior and posterior elements of the monotreme girdle are the epicoracoid and coracoid, respectively; and these are the 332 FRANK BLAIR HANSON homologues of the two similar elements found by Broom in Aus- tralian marsupials; and the author in the American species. The anterior of these two elements (epicoracoid) in the mono- tremes is a permanent feature of the adult skeleton, but disap- pears in the adult marsupial and does not reappear in higher forms. The posterior element, the coracoid, is a stout element in the monotremes and is present in the adult as in the fetus, while its marsupial homologue is the exact counterpart in the fetal condition, this later gives way through degeneration to the rela- tively small element (fig. 7) attached to the scapula in the adult. The coracoid process of mammals is, therefore, the homologue of the strong posterior coracoidal bar which connects with the sternum in the monotremes. That this is the correct view of the coracoid homologies between monotremes and marsupials and higher orders of mammals probably will not be seriously questioned. In passing from the monotremes to the reptiles there is a variety of opinion which is quite revealing of how little after all we have grasped of the real phylogeny of the mammals. Broom derives the present-day reptiles from a line of Permian ancestors in which the posterior coracoid was gradually lost, leaving the coracoid of Sphenodon, lizards, and the single cora- coid of the alligator as the homologue of the anterior coracoid ele- ment of the Permians. He, then, derives the mammals from an- other line of Permian stock in which just the reverse process — occurred, i.e., the anterior element now is thought to be the one lost and the posterior retained and homologous with the pos- terior element of monotremes and the coracoid process of other mammals. Williston (’11) admits the possibility, and even the probability, of two divergent lines of evolution, one in which the posterior coracoid is lost and leading to present-day reptiles, and one in which the anterior coracoid is lost, leading to the mammals, and he also points out that the absence of the coracoid foramen in the mammals may indicate that this has been the case. How- ever, Williston is very positive that the coracoid of Lacertilia, Dinosauria, Crocodilia, etc., is absolutely identical with the cora- THE PROBLEM OF THE CORACOID 333 coid of Seymouria and Varanosaurus, which is without doubt the anterior coracoid. He says: there cannot be the least doubt but that the posterior bone, the so- called coracoid, is unossified in Seymouria, as in Varanosaurus. The coracoid of all these forms consists exclusively of the anterior element, the so-called procoracoid. That this bone has entirely disap- peared in all later reptiles, giving place in its entirety to another bone, here unossified, with like attachments, and with its perforating supra- coracoid foramen in the same position, I cannot believe. It seems to me utterly improbable that the coracoid as ossified in the Seymouria and Varanosaurus is not identical with the bone supposed to be (with- out proof) the fused coracoid and procoracoid of Lacertilia, Dinosauria, ete., .°. . . the only thing I wish to insist upon is that the coracoid of Seymouria and Varanasaurus is absolutely identical with the coracoid of the Lacertilia, Dinosauria, Crocodilia, ete. Again discussing this same point under the genus Varanosaurus, Williston says: the absence of a posterior bone in this genus, as in Seymouria is remark- able. The whole pectoral girdle of Varanosaurus has an almost abso- lute superficial identity with that of the lizards. Under the usual interpretation, however, the large ossified coracoid of Varanosaurus, with its close resemblance to the coracoid of Varanus, for instance, in its supracoracoid foramen and fenestra, is the metacoracoid. In other words it is assumed that the coracoid of Varanosaurus has disap- peared gradually by the encroachment upon it of the posterior bone, the so-called true coracoid, which here in this genus was so degenerate that it no longer was even ossified. It seems to me that the utter absence of any proof that such has been the course of evolution in the pectoral girdle of reptiles—for no intermediate form has ever been discovered, no form in which the posterior bone has even reached as far forward as the supracoracoid foramen—is sufficient to throw great doubt upon the hypothesis, a doubt that becomes quite conclusive in the proof afforded by the various specimens of these and other Permian reptiles. It is a curious fact also that a posterior coracoid bone has never been observed in any temnospondyl, though the sutural division between the scapula and coracoid I have observed in specimens referred to Aspidosaurus to be quite as in Seymouria. Williston’s work is quite conclusive in homologizing the cora- coid of Sphenodon, lizards, and crocodiles with that of the anterior element (precoracoid) of Permian reptiles. 334 FRANK BLAIR HANSON Is it possible to pass from the lizards and Sphenodon to the monotremes? is the question now facing us. For if we accept the above arguments on the homology of the posterior element of monotremes with the coracoid process of mammals, and also assent to Williston’s view that the single coracoid of lizards and Sphenodon is the homologue of the precoracoid of fossil reptiles, then by bridging the gap between monotremes and living rep- tiles we shall have completed the homology of the coracoid from early Permian reptiles up to man. Gregory and Camp (’18) have compiled the evidence or given the basis for this latter homology between monotrenes and living reptiles. In the first place, it has been shown that the single coracoid of Sphenodon ‘‘gives origin on its ventral surface to a group of muscles comprising the biceps and the three branches of the Coracobrachialis, which group appears to be precisely homol- ogous with a similar group of muscles carried by the ventral sur- face of the coracoid of monotremes.”” The subecoracohumeralis of Sphenodon arises on the dorsal surface of the coracoid and is homologous with the similarly placed muscle, subcoracoideus, of the monotreme. As far as evidence from muscle goes, the coracoid (= precoracoid) of Sphenodon is identical with the coracoid of monotremes. Secondly, the epicoracoid of Spheno- don and the lizards is widely excluded from the glenoid exactly as in the monotremes and the embryos of marsupials. The rela- tions of the epicoracoid to coracoid, clavicle, and interclavicle are also identical in monotremes and living reptiles, and in each the ventral surface of the epicoracoid carries the anterior part of the supracoracoid muscle. Comparison of the monotreme cora- coid with that of the alligator shows practically the same thing. While there is only one coracoidal element (= precoracoid) in the alligator, Gregory thinks that with the loss of the clavicle in this form there undoubtedly also was lost a membranous epi- coracoid which lay between the interclavicle and the coracoid. If this should prove to be the case, the identity between the monotreme girdle and that of the Crocodilia is quite complete. In general, to quote again from Gregory and Camp (’18), “the whole complex of relations of the epicoracoid and coracoid THE PROBLEM OF THE CORACOID 335 of monotremes to each other and to the scapula, clavicle, and in- terclavicle, is practically identical with the relations of the same set of elements in lizards and Sphenodon”’ (figs. 3, 4, 5, and 6). There is, then, considerable evidence for comparing directly the coracoid of monotremes with that of living reptiles, and, as shown above, Williston, Broom, Gregory, and Watson unite in homologizing the single coracoid of crocodiles and Sphenodon and the posterior element in lizards with the precoracoid of Permian reptiles. If this reasoning is valid, then the coracoid process of man is a precoracoid and the homologue of the single coracoid of such Permians as Seymouria and Varanosaurus, and likewise homol- ogous to the anterior element of those Permians which possess two bony coracoids. Another question yet remains to be disposed of. If the coracoidal elements of the monotremes, Sphenodon, and the liz- ards are the homologues of the anterior element of Permian rep- tiles, what is the phylogeny of the so-called anterior element or epicoracoid of living reptiles and monotremes? Only one expla- nation has been offered, and that by Gregory and Camp, to the effect that in such a Permian as Moschops (fig. 5) and probably in others, there was really an epicoracoidal cartilage present be- tween the precoracoid and the clavicle and interclavicle. At least in fitting the bones of the shoulder-girdle of Moschops to- gether, it was found that there was a space between the clavicles, interclavicle, and precoracoids which must have been filled by the epicoracoids as in Sphenodon, lizards, and monotremes. ‘The same thing is indicated in Eryops. As shown above, the epi- coracoid, often appearing transiently as an embryonic structure in the marsupial, disappears from all higher forms. This means, of course, that according to Gregory there were originally three coracoid elements—metacoracoid, precoracoid, and epicoracoid—rather than the two usually considered. The admission of a third coracoid (epicoracoid) is denied by Watson, who says (in a private letter) ‘“‘that the presence of a distinct ossified ‘epicoracoid’ (as a third anterior element) in Permian vertebrates has never been proven.” 336 FRANK BLAIR HANSON While the existence of a third epicoracoidal element has not been proved by the demonstration of an actual specimen from Permian strata, there are several strong indications that such might have been the case. One of these has already been men- tioned, namely, that in the Permian Moschops between the pre- coracoid, clavicle, and interclavicle, there is a space direetly comparable with the one filled by an epicoracoid in the lizards and Sphenodon. Since the epicoracoid is a broad thin plate of membranous tissue, it naturally would be lost in the process of - fossilization. Other evidence that the epicoracoid was a fairly constant element of Permian reptiles is furnished by Case (’07, ‘lla, ’11b). Describing the skeleton of Dimetrodon dollovi- anus, he says, ‘‘the procoracoid terminates anteriorly in a thin, straight edge, which shows signs of having borne a heavy epicora- coidal cartilage.’ Dimetrodon has an ossified coracoid and a precoracoid, and if Case is correct, it also carried a heavy car- tilaginous epicoracoid on the anterior edge of the precoracoid. Since the cartilage would not be preserved, we have probably as near a demonstration of the presence of three coracoidal elements (metacoracoid, precoracoid, and epicoracoid) in Permians as will ever be obtained. That this is not an isolated case is shown in two other illustrations taken from Case. Describing the genus Diadectes Cope, Case (’11 a) says of the shoulder-girdle, ‘‘the coracoid and precoracoid are not separated from the scapula by suture. . . . The anterior edge (of the precoracoid) is nearly straight and shows the attachment of a cartilaginous epicoracoid of considerable size.’’ And again, Case (’11 b), quoting Cope’s description of Eryops megacephalus, gives the following account of the girdle: the coracoid is but little incurved; its internal border is convex, and is roughened as though for cartilaginous attachment. Its superior portion forms a con- vex continuum with the scapula. The direct line or external face of the scapula extends in a nearly plane surface to the glenoid cavity, embracing a perforating foramen above the latter, pre- cisely as in the Pelycosauria. Its surface is continuous anteri- orly with a wide expansion forwards, whose fine inner border is continuous with that of the coracoid. This plate doubtless —E—_ THE PROBLEM OF THE CORACOID 337 includes a third element, but its borders are not preserved, on account of the obliteration of the sutures. It is probably epi- coracoid, as in the Pelycosauria. From the foregoing, it is apparent that in several groups of Permian reptiles and in the primitive Eryops, there is consider- able evidence to support the theory of a third coracoidal element —the epicoracoid in front of the precoracoid. The following table shows the presence or absence of these several coracoidal parts in fossil and living forms according to the interpretation of the homology of the coracoid herein set forth. METACORACOID PRECORACOID EPICORACOID x = ° D ic) a ° uo} ie) ek * * % + e He % * ID PG TOUGR Se a oan ae ee eens RPE ELIMI LE ayclalc oleae VPie fon v= nS oan WIRREMUSHULUS oc am.ci tones sees 3) 0) 6(20 0 lee a Ae eee Am cs Srccard fyi sesjrars pe lesa sve pie UN AON feral slope axsih cys soe 21s | : MONOUFEMC cece ccc ce ces Marsupial fetus...:...../....-.- Marsupialadulti.: 2... 4. ociseu.s eS a CR OOR ee FB * = element is present. While the above table is not in any sense a phylogenetic one, it shows that in several groups of Permian fossils, relatives to the ancestors of the mammals, three coracoidal elements were present, and by the dropping out of either the most posterior element (meta- coracoid) or the most anterior element (epicoracoid), or both of these elements, all the variations met with from Permians to man are explicable. The relations and homologies here set forth will stand regard- less of what disposition is finally made of Gregory’s ‘‘epicoracoid or third coracoid element,” for the homologies of the coracoid all hinge upon the precoracoid as the constant and vital factor in the phylogenetic succession. 338 FRANK BLAIR HANSON The epicoracoid may be, for all anyone has shown to the con- trary, merely a neomorph, like the subcoracoid, with no morpho- logical significance. Regardless, then, of the fate of the epicora- coid, the following homology apparently is established, namely, that the precoracoid of Permians = coracoid of living reptiles = coracoid of monotremes = coracoid of marsupials = coracoid process of man. It is at once apparent that the precoracoid of Permian reptiles is the constant factor in the situation. Since, as shown by Wil- liston, this element (precoracoid) is the one preserved and known as the coracoid of Sphenodon, lizards, and the alligator, the term coracoid is correctly applied only to the homologues of the pre- coracoid. Gregory and the author have argued for the homology of the girdles of Sphenodon and lizards with that of the mono- tremes, and Broom and the author have shown that the conditions in the monotremes are directly comparable with the fetal girdle of the marsupials, therefore, the two elements of the girdle in the fetal marsupial (coracoid and epicoracoid) are homologous with the same two elements in the lizard and Sphenodon. But these elements of Sphenodon and the lizards are demonstrated by Williston and Case to be the homologues of the precoracoid and cartilaginous third element (epicoracoid) of Permian rep- tiles. Therefore, again, the two elements of monotremes and fetal marsupials are homologues of the precoracoid and car- tilaginous epicoracoid of Permian reptiles, and not to the precora- coid and metacoracoid, as assumed by Watson and Broom. In the fetal marsupial the epicoracoid is embryonic only, the coracoid aborts except for a small rudimentary process attached to the scapula, which is undoubtedly the homologue of the same- named element in higher mammals and man. Therefore, once again, the coracoid process of man is a precoracoid and the homologue of the precoracoid of fossil reptiles. It may be objected that the precoracoid of Permian reptiles, and its homologue in living reptiles, carried a foramen and nerve. This is not present in monotremes, and we must assume it to be lost here. This is not a serious objection, as the foramen is also absent from the coracoid of many birds, which coracoid is with- out question the homologue of the precoracoid. THE PROBLEM OF THE CORACOID 339 Also it may be pertinent to ask, if the coracoid process of pla- cental mammals is the posterior element of Permians, how did it get to the anterior side of the glenoid? It is hard to imagine any rotation or migration of this element which would bring it from a position distinctly posterior of the glenoid to its present distinetly anterior position. THE SUBCORACOID The subcoracoid center of placental mammals has been homol- ogized by Howes (’93), Lydekker (’93), and others to the metacora- coid of Permian reptiles. They regard the subcoracoid center of mammals as the vanishing vestige of the metacoracoid. Gregory (15) and also Williston formerly accepted this homology, but Gregory (’18) has reconsidered this element and now believes it to be a neomorph or cartilaginous epiphysis and without mor- phological significance. Hanson (719), in studying this subcoracoidal element in the pig (an animal lacking the coracoid pfocess), came to the con- clusion that this center of ossification in the pig was an epiphysis. The subcoracoid always occupies the anterior portion of the glenoid, just behind the coracoid process. The posterior part of the glenoid in mammals is formed by the lower end of the scap- ula. To accept the subcoracoid element as the last remaining rudiment of the metacoracoid, it would be necessary to assume that in some way there was a rotation of the scapula so that the posterior side of the glenoid in Permian reptiles is now the anterior side of placental mammals, or else in some manner that this center has migrated across the glenoid cavity anteriorly to its present position. Either of these explanations puts our credu- lity under a rather heavy strain. Gregory and Camp (18) also point out in this connection that the subcoracoid ‘‘is located at the anterior end of the glenoid ligament where the latter is continuous with the tendon of the biceps . . . . as the intrasecapular position of part of the biceps is undoubtedly a neomorph in the placentals, we sug- gest that the appearance of a subcoracoid is also a neomorph.” 340 FRANK BLAIR HANSON Broom was the first to suggest that the subcoracoid was an epiphysis, and not part of the coracoid complex. SUMMARY 1. It has been shown by Broom for Australian marsupials and the author for the American opossum that in the embryo and fetus, the shoulder-girdle consists of a scapula, a clavicle, and two coracoidal elements, one of which, the posterior, extends from the scapula to the sternum and is comparable directly with the coracoid of monotremes. The anterior element of the marsupial fetus is a broad fan-shaped sheet of mesenchyme, of short dura- tion in embryonic life, and is the homologue of the epicoracoid of monotremes. 2. Development shows that the posterior of the two coracoidal elements of the fetal marsupial girdle becomes the small cora- coid process attached to the scapula in the adult, which process undoubtedly is homologous with the same-named process in man. This gives a clear line of relationship from the cora- coid process of man to the posterior element in the girdle of the monotremes. 3. Gregory and the author have maintained that the condi- tions in the monotreme girdle are so clearly reptilian in charac- ter and approximate so closely in every respect to the structure of the girdles in Sphenodon and the lizards, that genetic relation- ship and homology exists between them. 4. Williston has practically demonstrated that the coracoid of living reptiles is derived from the anterior bony element (pre- coracoid) of Permian reptiles. 5. Therefore, if the coracoid process of man is the same ele- ment as the posterior coracoid of monotremes, and this latter is directly comparable with the posterior of the two coracoids of Sphenodon and lizards, which is in turn a derivative of the pre- coracoid of Permian reptiles, then the coracoid process of man equals the anterior bony element of Permians, and the precoracoid is the true coracoid, 6. The subeoracoid of placental mammals is not a coracoid ele- ment at all, but an epiphysis, and does not enter into the prob- lem of the coracoid. THE PROBLEM OF THE CORACOID 341 LITERATURE CITED Broom, R. 1897 On the existence of a sterno-coracoidal articulation in a fetal marsupial. Jour. Anat. and Physiol., vol. 31. 1898 Description of shoulder-girdle in an 8.5-mm. embryo of Tricho- surus (not exact title). Proc. Linn. Soc. N.S. W. 1899 On the development and morphology of the marsupial shoulder girdle. Trans. Roy. Soe. Edinb., vol. 39, pt. 3. 1902 On the early condition of the shoulder girdle in the Polyproto- dont marsupials Dasyurus and Perameles. Linn. Soc. Jour. Zool., vol. 28. 1912 The morphology of the coracoid. Anat. Anz., Bd. 41. Casn, E. C. 1907 Revision of the Pelycosauria of North America. Carnegie : Institution of Washington, Pub. no. 55. 1911 a A revision of the Cotylosauria of North America. Carnegie Institution of Washington, Pub. no. 145. 1911 b Revision of the Amphibia and Pisces of the Permian of North America. Carnegie Institution of Washington, Pub. no. 146. Grecory, W. K., anp Camp, C. L. 1918 Studies in comparative myology and ‘ osteology. No. III. Bull. Am. Mus. Nat. Hist., vol. 38. Hanson, F. B. 1919 The coracoid of Sus scrofa: Anat. Rec., vol. 16. Howes, G. B. 1893 On the coracoid of the terrestrial animals. Proc. Zool. Soc. London. Lyprekker, R. 1893 Notes on the coracoidal element in adult sloths, with remarks on its homology. Proc. Zool. Soc. Parker, W. K. 1867 A monograph on the structure and development of the shoulder girdle and sternum. Ray Society, London. Watson, D.M.S. 1917 The evolution of the tetrapod shoulder girdle and fore- limb. Jour. of Anat., vol. 52. ; Witutston, 8S. W. 1911 American Permian vertebrates. University of Chicago Press. ABBREVIATIONS Ac, acromian ICl, interclavicle Cl, clavicle MCr, metacoracoid Cleith, cleithrum PCr, precoracoid Cr, coracoid PSt, presternum ECr, epicoracoid Sc, scapula Gl, glenoid SSc, suprascapula Hu, humerus St, sternum PLATE 1 EXPLANATION OF FIGURES 1 Transverse section of the shoulder-girdle and sternum of a 7.5-mm. em- bryo of Didelphys virginiana. Scapula and coracoid continuous at glenoid Coracoid extends to and unites with the sternum. Series 924, slide 3, section 35, Harvard Embryological Collection. 2 Frontal section of the shoulder-girdle and sternum of 11.5-mm. embryo of Didelphys virginiana. This section shows the connection of the large cora- coid with the sternum, but is cut in such a plane as to exclude the scapula. Series 6127, slide N, section 5, Harvard Embryological Collection. 342 (5 PROBLEM OF THE CORACOID , PLATE 1 FRANK BLAIR HANSON ANATOMICAL RECORD, VOL. 19, No. 6 _ PLATE 2 EXPLANATION OF FIGURES Shoulder-girdle of iguana. Modified after Parker and Gregory. Shoulder-girdle of Sphenodon. Modified after Gregory and Camp. Shoulder-girdle of Permian Moschops. After Gregory and Camp. Shoulder-girdle of the monotreme, Ornothorynchus. | Shoulder-girdle and anterior part of sternum of the marsupial Petrogale xanthopus. Note small rudimentary coracoid process and compare with cora- coid in figures 1 and 2. “IG Or mm THE PROBLEM OF THE CORACOID PLATE 2 FRANKE{BLAIR HANSON Resumen por el autor, Homer B. Latimer. Universidad de Nebraska. Peso de las visceras en la tortuga. Veintitin machos y una hembra de la tortuga de Cumberland (Chrysemis elegans) fueron empleados en el presente trabajo. Después de cloroformizados se pesaron, disecsndoles a continua- - cién y extrayendo las visceras, que se pesaron, en frascos de pesar con tap6n de vidrio, en una balanza quimica que podia apreciar diferencias de una décima de miligramo. El peso ordinario de las visceras expresado en tantos por ciento del peso total es el siguiente: el coraz6n, 0.31; el bazo, 0.21; los pulmones y traquea, 1.07; el tubo digestivo sin su contenido, 6.23; el higado, 5.43; el pancreas, 0.15; los rifones, 0.31; y los testiculos 0.23 por ciento, o sea un total de 13.74 por ciento del peso total del cuerpo. Cuando se emplearon los pesos absolutos del cuerpo y de cada 6rgano para determinar el coeficiente de variabilidad, el autor hall6é que el peso del cuerpo posee un coeficiente menor — que el de cualquiera de los 6rganos. Los 6rganos que poseen un coeficiente de variabilidad menor son generalmente los érganos” con un coeficiente mas alto de correlacién con el peso total del cuerpo. Naturalmente, los coeficientes de variabilidad de los. érganos son mas pequefios cuando en vez de los pesos absolutos se emplean los pesos en tantos por ciento. Estos ultimos se obtienen reduciendo los absolutos a un por ciento del peso total del cuerpo. Translation by José F. Nonidez Cornell Medical College, New York AUTHOR'S ABSTRACT OF THIS PAPER ISSUED BY THE BIBLIOGRAPHIC SERVICE, OCTOBER 4 THE WEIGHTS OF THE VISCERA OF THE TURTLE! HOMER B. LATIMER Department of Zoology, University of Nebraska The frequent use of the turtle for laboratory purposes and the lack of quantitative data on the size of the turtle viscera has made it seem worth while to determine the weights of the viscera of the turtle. Another thing which suggested this problem was the question of the effect of the weight of the turtle shell on the percentage weights of the organs. The only published quanti- tative work on the turtle viscera of which I am aware is the report of Welcker and Brandt (’03) upon a single female specimen of Testudo graeca. The brain and spinal cord of each turtle were removed, measured, and weighed, and this data will be combined with similar data from other forms and published later. MATERIAL AND METHODS The specimens used in this investigation were twenty-one male and one female Cumberland terrapins (Chrysemys elegans), three Southern musk turtles (Aromochelys tristata), one male and two females, and one male specimen of Lesueur’s terrapin (Mala- coclemmys lesueurii). The turtles were killed with chloroform. The small turtles were weighed on a chemical balance sensitive to a tenth of a milligram, the larger turtles, the Cumberland terrapins, were weighed on a laboratory balance sensitive only to atenth of a gram. The viscera were carefully dissected out and immediately put in ground-glass-stoppered weighing bottles after all the excess blood had been allowed to drain off. The lungs and trachea were weighed together, the trachea being severed at its attachment to the pharynx. The oesophagus was cut away 1 Studies from the Zoological Laboratory of the University of Nebraska, no. 126. 347 348 HOMER B. LATIMER from its attachment to the pharynx and the large intestine was severed at its opening into the cloaca. The entire tract was removed with as little of the surrounding fat and the mesenteries as possible. The stomach and intestines were opened and the contents removed. What little material there was in the intes- tine could usually be forced along the intestine by gentle pressure until it could be removed at the end or at one or two incisions. All the other viscera were removed in a similar manner with as little of the mesenteries and fat as possible. The net body weight and the percentage of loss were not determined as they were for the frogs (Latimer, ’20), but in other respects the same plan, which was described in the previous paper, was followed in the dissection and weighing of the turtles. The twenty-two Cumberland terrapins were received from a Chicago dealer, and the fact that but one of the twenty-two was a female is interesting. They were kept in a tank with free access to running water in a room with a temperature slightly below the usual laboratory temperature. The first turtle was killed and studied December 23, 1919, or soon after they were received. The last one was killed January 26, 1920. They received no food during this time, and when killed only small masses of fecal material were found toward the caudal end of the intestines. They all had ample quantities of fat in the mesenteries, showing that they were in good condition. PERCENTAGE WEIGHTS OF THE VISCERA Table 1 A gives the total weight in grams of each of the twenty- one male Chrysemys elegans and the weights of the viscera of — each turtle expressed in percentages of the total body weight. — Sections B, C, and D give the same data for the one female Chrysemys elegans and for the other turtles. The weights of the digestive tract are for the empty tract. There was so little material to be removed that no correction was made for this in the total body-weight. Table 2 will facilitate comparisons between the turtles and other species. It shows the averages of the percentage weights WEIGHTS OF THE VISCERA OF THE TURTLE 349 of the various organs of the turtles and the same data for the other forms. ‘The first line gives the average percentage weight of the organs of the twenty-one male turtles (C. elegans). The second line gives the averages for the three Southern musk tur- tles, and the third line the percentage weights of the viscera of the one Lesueur’s terrapin. The data for the first three lines are taken directly from table 1. The percentage weights for the Tes- tudo graeca are taken from the report of Welcker and Brandt (03) and are for a single female specimen. The next two lines give the average percentage weights of the organs of the ten male and nineteen female frogs (Rana pipiens) from a previous paper (Latimer, ’20). The percentages of the rat viscera are those given by Jackson (’13) for one-year-old male white rats. The last line gives the data on the human organs as given by Vierordt (’06). The last column of the table shows the totals of the percentage weights for all the viscera of each species. These were determined from the four-place decimais of the com- plete tables, and consequently the sums are slightly larger than the sums of the two-place decimals given in this table. It is obviously impossible to place much weight on the figures in the second, third, and fourth lines, for these three lines represent altogether but five specimens. In comparing the twenty-one male turtles with the frogs it is apparent that each of the organs of the turtle is heavier than the same organ of the frog, with the exception of the heart and the kidneys. Heart. The heart forms a smaller percentage weight in the turtles than in any of the other forms. Joseph (’08) suggests that the relative size of the heart is correlated with the activity of the animal. This would place the turtle at the bottom of the list as far as activity is concerned, and the Chrysemys elegans would be more active than the other three species of turtles, if we may be permitted to judge from the very small numbers. The percentage weights of the heart for the frog, the rat, and the human are nearly the same. Spleen. The spleen is the most variable organ not only in comparing the eight species listed in this table, but in comparing (re reeseeeressss GONMIAOP pLUPUNIS E77 O £2180 £1510 erer' ¢ . 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LATIMER the individual twenty-one male turtles and the twenty-nine frogs. It is thirteen times heavier in the rat than in the three musk turtles. Lungs. The weights of the lungs in terms of percentage of the total body weight are heavier in the turtle than in the frog. In weighing the turtle lungs the trachea is included. This might account for the difference, but the turtle lung is a more compli- cated structure than the simple sac-like lung of the frog. No separate weighings of the trachea were made. Digestive tract. The digestive tract in the Cumberland terra- pins, Testudo graeca, and the white rat is much heavier than the TABLE 2 Showing the average percentages of the viscera for the following species HEART | SPLEEN| LUNGS Epi e LIVER cae NEYS TOTALS GFelepans sig. be cits en oo 0.31 | 0.21 | 1.07 | 6.23 | 5.43 | 0.15 | 0.31 | 13.74 Whrnic Corte .vs.. ace sees 0.28 | 0.03 | 0.92 | 3.388 | 2.40 | 0.14 | 0.27] 7.45 Lesueur’s terrapin......... 0.24 | 0.18 j 1.14 | 3.11 | 3.75 | 0.13 | 0.24) 8.83 Test. GYBGCG. . (22 oss ee at 0.23 | 0.10 | 1.71 | 5.68 | 5.78 | 0.14 | 0.62 | 14.26 Male trogaies ss <2 ses xe ove 0.43 | 0.18 | 0.85 | 3.50 | 2.80 | 0.09 | 0.43] 8.31 Female frogs.............. 0.47 | 0.16 | 0.76 | 3.77 | 2.88 | 0.09 | 0.47 | 8.63 RINGER Ee Glas ws hig rele 0.45 | 0.39 | 0.93 | 5.1 | 4.42 0.95 | 12.25 RUNANIE hts sccuteoae 0 ca be 0.46 | 0.25 | 1.50 | 2.06 | 2.75 | 0.15 | 0.46] 7.63 percentage weights in the other forms. The lower percentages in the frogs, the musk turtles, and Lesueur’s terrapin may have been due to the fact that they were kept in the laboratory for some time before being killed. ‘The Cumberland terrapins were kept in the laboratory for only a little over one month, and that was during the winter time, while the frogs and the other turtles were kept for a longer time and during the summer. It is inter- esting to note that the percentage weight of the human digestive tract is the lowest and that of the Cumberland terrapin the highest, or a little over three times the percentage of the human digestive tract. Liver. The variation in the percentage weights of the liver in comparing one form with another seems to parallel the varia- WEIGHTS OF THE VISCERA OF THE TURTLE 353 tion in the digestive tracts. The human, the Testudo graeca, and Lesueur’s terrapin are the only forms in which the liver is heavier than the digestive tract. Only five of the twenty-one male turtles had a liver with a heavier percentage weight than the digestive tract. Pancreas. The pancreas forms nearly the same per cent in all forms except the frogs, where it is much less. Kidneys. The kidneys show a marked variation, the kidneys of the rat being 3.95 times heavier than the kidneys of the Les- ueur’s terrapin. The kidneys of the three terrestrial forms, the rat, the human, and the Greek tortoise, are heavier than the kidneys-of the aquatic forms. The adrenals were included in the weights of the kidneys of the turtles which I weighed, and of the frogs. A comparison of the sums of the percentage weights of the vis- cera of the turtle (C. elegans) and the frogs is interesting, the former being 1.6 times heavier than the latter. This means that either the organs of the turtle are relatively larger than those of the frog or that the better-developed musculature or other parts of the frog more than compensate for the shell of the turtle. The sum of the percentages for the human most nearly resembles the sum of the percentages of the musk turtles, which were undoubtedly undernourished, due to their prolonged period in the laboratory, and the normal healthy rats resemble more closely the sum of the percentages of the turtle. If we omit the one specimen of the Greek tortoise, we find the viscera of the Cumber- land terrapin the heaviest, with the weights of the viscera of the white rat a close second. COEFFICIENTS OF VARIABILITY In table 3 are shown the coefficients of variability of the per- centage weights of the viscera of the twenty-one male Cumber- land terrapins and of the ten male and nineteen female frogs. The coefficient of variation and the probable error of the coeffi- cient of variation for the turtles are taken from table 1. The coefficient of variation and the probable error of the coefficient of variation for each organ of the frogs were computed from the 354 HOMER B. LATIMER data given in table 2, page 39, of the report of the frog viscera (Latimer, ’20), which gives the percentage weights of the viscera of the chloroformed frogs, Rana pipiens. In finding the standard deviation, the coefficient of variation and coefficient of correla- tion and the probable errors of each of these, Pearson’s formulae, as given by Davenport (’04), were used. A six-place logarithm table and the table of squares given by Davenport (’04) aided in the computations. All the results were checked. This table shows the turtle spleen with a coefficient of varia- tion of 33.46 + 3.85 or four times that of the digestive tract. The frog spleens have a still higher variability, or 71.0 + 15.1 TABLE 3 Coefficient of variability of percentage weights MALE TURTLES MALE FROGS F FEMALE FROGS Digestive tract 8.05=0.84| Kidney........ 11.51.7 | Kidney....... 12.9=1.4 Divers: eee: 9.42+0.98] Digestive tract 12.61.9 | Liver......... 19.6 =2.2 Heart... 3. .«:.15< 10.83=1.27) Heart.......... 13.42.0 | Lungs......... 20.7 =2.3 Kidney........ 12 .43=1.31} Liver.......... 15. 42.3 | Digestive tract21.6=2.4 Pancreas....... 23 .12=2.47| Lungs.......... 1772.7 | Heart......... 22.2 =2.5 PUN Cann: 27 032.91} Pancreas.......22.2=3.5 | Pancreas...... 24.5 = 2.8 Spleen.........33.46=3.85) Testes......... 47 28.5 | Ovaries..... 1.52.1 +7.0 TORS. ciiy ota 35.654.15) Spleen......... 71.0+15.1) Spleen........ 64.7 =9.6 for the male and 64.7 + 9.6 for the female frogs. This it will be seen is greater than the coefficient of variation of either the testes or the ovaries of the frog. The low coefficient of variation of the digestive tract of the turtle is noticeable, due possibly to the lack of food for a similar length of time and uniform condi- tions of temperature and so forth. The kidney, which is fourth in variability in the turtle, ranks first with a variability of 11.5 + 1.7 in the male and 12.9 + 1.4 in the female frogs. The pancreas seems to be about the same in all three columns, with a coefficient of variation of 23 for the turtles, 22 for the male frogs, and 24 for the female frogs. The ovaries, as might be expected, show a greater variability than do the testes, and both gonads of the frogs show a greater variation than do the testes of the WEIGHTS OF THE VISCERA OF THE TURTLE 355 turtles. The heart is third in two columns and fifth in the third, the lungs are sixth in order of the increasing coefficient of varia- bility in the turtle, fifth in the male frogs, and third in the female frogs. Table 4 gives the data for the weights of the organs in grams; A gives the data for the twenty-one male turtles and B for the TABLE 4 Showing average weights, standard deviations, and coefficients of variability, computed from the actual weights of the organs in grams AVERAGE STANDARD COEFFICIENT OF WEIGHT es DEVIATION VARIABILITY A. Twenty-one male turtles grams Body weight... 0222.2... 839.79 688 .9-1001.1 89.685 | 10.67 + 1.12 LEIGH co ee ee eG acl eee 2.6465) 2.0858-3 .2462 0.292 | 11.06 + 1.16 SYS GGT RS hee ee ee eee 1.8226) 1.0341-3.7120 0.699 | 38.36 + 4.54 ILI SS de Je Re Des Dee ee aero 8.9475) 6.5932-17 .2002 2.435 | 27.22 + 3.03 Digestive tract............ 52.3223) 41 .0200-67 .7790 6.901 | 13.19 + 1.39 MMe eee ee clkesa - 45.7266) 30.5501-61 .9637 8.993° | 19.66 + 2.12 PANIURCAS SS Skyy. 5.15 A isicils 1.3204) 0.9410-2.4125 0.338 | 25.65 + 2.84 WOME YS Dee is ! ims Acta ieee Vuh llt he Dahesh Gy Ae AT AN Sh: sine “arte. meet: Mua sg Milt at iri > t 4 i] y Poo th, ra A edit Hi aerot othe ay vi | Y wa ; 7 ri { » i) ae a} * 7 Y, ; . Resumen por el autor, Otto F. Kampmeier. Universidad de Illinois. La circulaci6n colateral en un caso de oclusién completa del orificio de la vena cava superior. El orificio de la vena precava y de la mayor parte de la eémara atrial de un coraz6n humano aparecian obstruidos a consecuen- cia de la formacién de un gran trombus en el atrio derecho, suf- riendo dicho trombus una calcificacién subsiguiente. Los cambios resultantes en la direecién y marcha de la corriente venosa pueden resumirse brevemente del modo siguiente: Toda la sangre que vuelve al corazon desde la porcién del cuerpo situ- ada sobre el diafragma, excepto la procedente de las venas coro- narias, tenia que descender, principalmente por el sistema de las venas azigos, a la cavidad abdominal, donde penetraba en la post- cava. La direccién de la corriente sanguinea en el sistema de las venas azigos, era pues, completamente contraria a la direccién de la misma corriente en el cuerpo normal. Estas modificaciones se han expresado mediante dos esquemas que acompafan al trabajo. Translation by José F. Nonidez Cornell Medical College, New York AUTHOR'S ABSTRACT OF THIS PAPER ISSUED BY THE BIBLIOGRAPHIC SERVICE, OCTOBER 4 THE COLLATERAL CIRCULATION IN A CASE OF COMPLETE CLOSURE OF THE MOUTH OF THE SUPERIOR VENA CAVA OTTO F. KAMPMEIER Department of Anatomy, College of Medicine, University of Illinois, Chicago, Illinois TWO FIGURES ‘The case, here described, is that of a negress of middle age, who died of pneumonia in the course of chronic mania. The body was muscular and well nourished; of short stature, being less than five feet in height, it weighed 150 pounds. Surface examination showed a large ulcer on the lower lateral side of the right leg. This character and certain of the internal abnormali- ties found later led one to suspect syphilis, which diagnosis was subsequently substantiated by the woman’s clinical history at the insane asylum! where she had been confined. The records revealed that she was a prostitute and a criminal; she committed murder, evidently in a fit of madness, for she was placed in a hospital for mental diseases (1901) and, fourteen years later (1915), was admitted to the asylum for mentally diseased. The clinical data further showed that she had been under syphilitic treatment for years. During the dissection? of the cadaver, a considerable number of abnormalities were observed, chief of which were those of the heart, to be described presently, also a large fibroid of the uterus, a fairly large lipoma of the back in the lumbar region, softening 1 Asylum for Mentally Diseased in Wauwatosa, near Milwaukee, Wisconsin. I thank Dr. F. W. Beutler, director of the institution, for looking up the records of the case. : 2 The dissection was carried out by two of my students, Messrs. J. A. Blair and A. J. Raymond, at the Marquette School of Medicine, Milwaukee, and the figures were copied from my diagrams and prepared for publication by Mr. L. Massopust, the artist of the school. 361 362 OTTO F. KAMPMBIER of a large part of one lobe of the cerebrum (which apparently was not due to postmortem changes following imperfect preser- vation), marked circulatory deviations, chiefly of the veins, and a number of easily recognizable muscular anomalies, especially of the upper extremity. In fact, the students in the dissecting laboratory claimed ‘‘everything was wrong with her.” When the heart® was examined and studied, the major portion of the right atrium as well as an extensive area of the aortic arch was found to be bony hard. On laying open the chambers of the heart, it was discovered that not only the entire wall of the right atrium, except where the inferior vena cava and coro- nary sinus entered, but also the entire interatrial septum was composed of a thick, compact ‘osseous’ tissue. Moreover, this tissue had extended far up through the anterior or ventral wall of the root and arch of the aorta and had invaded the atrio- ventricular septa partly surrounding the tricuspid and mitral valves. What was most remarkable about this calcified tissue was its great thickness, in many places measuring from 6 to 8 em. (2 to 3 inches) across. Even though the ventricular walls, except the atrioventricular septa, were for the most part free from the sclerotic deposit, it is a mystery to the writer how the contractions of the heart could have been sufficiently complete to propel the vascular stream throughout the body. The most notable change occurred in the right atrium. Here the sclerotie layer had become so massive as to have occluded the major part of the atrial chamber, shutting off entirely the superior vena cava, but leaving a lumen approximately as wide as that of the inferior vena cava for the passage of the blood from the latter vein and the coronary sinus to the tricuspid portal. To give actual dimensions, the average thickness of the sclerosed inter- atrial septum was about 3 em. (1} inches), while that part of the bony wall situated between the end or original mouth of the superior vena cava and the remnant of the atrial cavity was no less than 5.5 em. (slightly more than 2 inches). The latter relations are indicated in figure 1. * This specimen, numbered M. 344, is in the Museum of Pathology of Mar- quette Medical School. ag COMPLETE OCCLUSION OF MOUTH OF. PRECAVA 363 The excessive encumbrance to the heart of the sclerosed areas just pointed out had produced a compensatory hypertrophy of the remainder of the heart, although perhaps not to the degree one should expect. The ventricles were somewhat dilated, their muscular walls were correspondingly thick, and the beginning of the aorta was at least twice as wide as in the normal individual. Besides the pathological features already pointed out, the intima superior vena cava pulmonary vein entering left atrium sclenosed thrombus inferior vena cava = == tricuspid valve mouth of coronany sinus Fig. 1 Semischematic sketch of the right upper portion of the heart, showing one half of the right atrium cut away and illustrating that part of the massive sclerosed thrombus, situated between the orifices of the venae cavae and occlud- ing most of the atrial chamber. Approximately one-half natural size. or lining of the aortic arch was beset with numerous rough or thin, scaly, bony patches.‘ A section of the sclerosed wall of the right atrium was prepared for the microscope, which showed definitely, according to Pro- fessor McJunkin,® that it represented an organized thrombus. 4 Besides the sclerotic patches on the inner surface of the aorta, there were also little pits or depressions and small, parallel ridges, which I believe are consid- ered indicative of syphilis. In a fixed specimen, however, such depressions and elevations must be taken with reserve. 5 Prof. F. A. McJunkin, formerly of the Department of Pathology, Mar- quette School of Medicine, now of the Department of Pathology, Washington University Medical School, St. Louis. 364 OTTO F, KAMPMEIER In structure it displayed dense fibrous tissue which had under- gone widespread calcification. There were certain peculiarities which suggested syphilitic lesions as a possible initial cause of the thrombus formation. Perhaps it is more likely, however, that the latter began from a secondary infection of some sort, possibly streptococcie in origin, producing a thrombus which arose on the atrial wall itself, or, carried thither from a distant part of the body, became adherent and, gradually growing larger by ~ successive depositions of fibrin, eventually blocked ee cavity as demonstrated. The complete closure of the mouth of the superior vena cava by the atrial thrombus consequently led to extensive modifica- tions in the course and direction of the venous flow from the upper parts of the body to the heart, as illustrated in the dia- gram, figure 2. These changes may be briefly summarized as follows: 1) All blood returning to the heart from the body above the diaphragm, except that from the coronary veins, was forced to descend to the abdominal cavity, where it discharged into the inferior vena cava. 2) The direction of the blood stream in the azygos system of veins was the exact reverse of that in the normal body. These points are expressed in the diagram (fig. 2) by arrows. Much of the venous drainage of the head and arm flowed dir- — ectly into the azygos and hemiazygos veins through the anasto- moses of the right and left supreme intercostal and accessory hemiazygos veins with the innominate and vertebral veins. The remainder passed into the superior vena cava, but being unable to enter the right atrium on account of the occlusion of its ori- fice, it was deflected into the mouth of the azygos vein. From here this blood stream, in conjunction with that coursing through the right supreme intercostal, continued downward in the azygos — vein; some of it, however, was turned to the left side through the hemiazygos, thus in direct opposition to the normal course of the flow. All blood passing through the entire extent of the azygos, and most of the blood of the hemiazygos poured via a pair of anastomoses. into the interior vena cava immediately below the diaphragm and at the level of the entrance of the COMPLETE OCCLUSION OF MOUTH OF PRECAVA 365 iS \ V, V. jugularis externa vertebral dextra V.subclavia dextra V. jugularis interna Sinistra Wileavai superior V.anonyma sinistra V. intercostalis suprema dextra V. intercostalis suprema sinistra —Sclerosed thrombus in right atrium V. azygos Remnant of right atrial cavity V. intercostalis 6 accessonia V. cava inferior V. hemiazygos Diaphragm ———. —Diaphragm W.hepaticae V.renalis sinistra V.lumbalis I V. lumbalis ascendens V.iliaca communis V.sacralis media V. hypogastrica sinistra Viliaca externa dextra Fig. 2 Diagram showing the closed mouth of the superior vena cava and the resultant modifications in the course and direction of the venous blood stream. 366 OTTO F. KAMPMEIER hepatic veins. These anastomoses, which when present in the normal individuals are minute and relatively unimportant, had become very much distended by the demands put upon them. Some of the blood stream of the hemiazygos continued still farther down through the abdominal cavity to empty into the inferior vena cava partly through the left renal vein and partly through the left first lumbar vein. The valves which are usually assumed to be present in the proximal segment of the azygos vein apparently offered no ob- stacle to the reversal of the vascular current flowing through it. But such valves do not always exist, and when existent are ‘nicht schlussfihig,’ according to Spalteholtz (Handatlas der Anatomie, Bd. 2). Valves which are unable to close the lumen perfectly lose their value in determining the direction of the flow when the caliber of the vessel becomes greatly expanded, as occurred in the case of the azygos under consideration. Besides the deep and important collateral pathways already mentioned, it is possible that much of the superficial haemal drainage of the thoracic wall, which normally discharged into the axillary, subclavian, and innominate veins through the thora- colateral, internal mammary and other smaller veins, was in this instance absorbed by the thoraco-epigastric and the super- ficial and deep epigastric veins to be carried to the femoral — and iliac veins and thence to the inferior vena cava. , | Ao, rf : OD CL an Vs ’ 4 - wn! Diy a 4 f ete CP a a pati Tos) Getivpsiis > = ce ae dat, i poets n! D* pstpren pa! : : t ie asta "} Wiig ‘ af hy et wer Aji ah Ae ' vy rr Lins We) , - , Lane ine nina Jyhandayas Ten a oohgs _ i, ee Fgh -_ . dey ve inh ng fet Yi Melis di “4 ta babi Tas) « ty ' F Or, eel SAR Ae ob: ph sthy ANN ; mn, nolMetive u ‘Atay Wes! ike 4) j wiht ahs ailode, Bal) DA; \\" Resumen por el autor, Edgar D. Congdon. Un seno paranasal supernumerario. La cavidad situada medialmente en la regi6n de la fosa incisiva y los canales del mismo nombre de un adulto, presentaba forma ovoidea y posefa una capacidad de unos 3 centimetros. Su pared 6sea no era completa por debajo, mientras que por encima se continuaba con las cavidades nasales mediante los cortos canales incisivos. La formaci6én de esta cavidad debe atribuirse probablemente a la fusion incompleta de los procesos nasales medio y lateral, asf como a la actividad formadora de senos del epitelio respira- torio, que ocupa normalmente el extremo superior de los canales incisivos en vias de desarrollo. Translation by José F. Nonidez Cornell Medical College, New York AUTHOR'S ABSTRACT OF THIS PAPER ISSUED BY THE BIBLIOGRAPHIC SERVICE, NOVEMBER 15 A SUPERNUMERARY PARANASAL SINUS E. D. CONGDON Department of Anatomy of the Leland Stanford Junior University Medical School ONE FIGURE The cavity shown in the accompanying figure was found by a student while making a sagittal section of an adult head. It is medially placed and extends upward from the region usually occu- pied by the incisive fossa. It is of a regular ovoid form, 9 mm. in height, 5.5 mm. in anteroposterior diameter, and its width is 8.5 mm. if 2 mm. be allowed for the section removed by the saw. Its interior is lined by a smooth membrane which contained a cyst in the right-hand wall 2 mm. in diameter, whose contents was evidently mucoid in nature. A small deposit of similar appearance lay upon the floor of the cavity. The bony wall of the space contained above a pair of sym- metrically placed short passageways, one of which opened into each nasal cavity, where their location and contents of nerves and blood-vessels identified them as the upper ends of incisive canals. At the palatine end bone was lacking over an area sev- eral millimeters in diameter, but the gap was filled upon either side of the saw cut by the membrane lining the cavity and the layers investing the bone of the palate. No communication into nose or mouth was found. Upon microscopic examination the lining membrane proved to be largely fibrous, but covered on the inner surface by a thin layer of columnar epithelium whose precise structure could not be made out because of maceration. The frequent presence of abscesses in the alveolar process makes it necessary to consider the likelihood of a pathological origin of the cavity. The neighboring bone and teeth seemed sound. The osseous and membranous walls showed no deteri- 367 368 ER. D. CONGDON oration other than the maceration of the epithelium, and this was judged to have taken place after death. The region of the incisive fossae was examined in 128 paired and single maxillae in a search for other cavities similar to the one under discussion. The fossae not infrequently bear a slight resemblance to it, as they may be deeper than wide and some- what narrowed at their inferior end. They are, of course, much smaller and usually of slightly irregular outline. Two of the series, however, show a distinct resemblance to it in the regularity and roundness of their contour, though they differ in being but slightly constricted below. There is a remote possibility, then, that they also may have contained cavities lined with mucoperi- osteum. The continuity of the bony cavity with the incisive canals in our specimen is an indication that it may have been related to them in development. Leboueq (’81) agrees with the observa- tions of Dursey (’69) and His (’01) whose work was accessible only in references from other writers, that the bony incisive canals surround in the embryo an epithelial tube called the incisive duct which is the result of a reopening of a part of the originally free communication between the spaces above and below the palatine processes. For a time after the median nasal and the palatine portion of the maxillary processes have fused, the duct, though closed, is represented by an epithelial cord continuous with the lining of the nose and mouth. The lumen of the incisive duct which develops in this cord usually disappears a second time permanently before birth. It seems probable that the cavity here described had its begin- ning either in the incisive ducts or the passageway from which they are derived. If it arose from one or both ducts, it must have undergone a subsequent enlargement, and since it is lined with columnar epithelium which was probably once continuous with the nasal cavity, it would have claim to classification as a paranasal sinus. This interpretation encounters the difficulty that the connection of the bony cavity with both incisive canals must have been the result of a fusion of their lumina—a process rare in sinus development. A SUPERNUMERARY PARANASAL SINUS 309 It is more probable that the cavity came into existence as a result of a failure in the meeting of the median nasal and the maxillary processes in this region so that a single large space remained where the lower parts of the incisive ducts usually developed. If this supposition is correct, both a change in the form and an increase in the size of the cavity must have occurred, since a space left between three rounded processes would not have an ovoid form and it could not have equalled in size this cavity of the adult bone. A possible difficulty for either expla- nation is that the columnar epithelium extends close to the Right half of sinus at (a) exposed by a median sagittal saw cut. X 1 oral surface of the maxilla, while Leboucq found that it gave way in the incisive ducts to the pavement type midway in their course. The exact position of the boundary line is probably not significant, however, since the corresponding transition zone also varies considerably in the nasopharynx. Works upon palatine malformations and upon the development of the incisive ducts were consulted, including Leboueq (81), Merkel (92), Le Double (96), and His (’01), without finding any reference to a cavity in this region. The studies of the para- nasal sinuses by Zuckerkandl (’82), Gruber (’88), Onodi (’07, OS), Underwood (07), and Shaeffer (10 and ’10 a) do not de- 370 E. D. CONGDON scribe a sinus here. There is a single record of a similar cavity by Meyer (713). In his specimen the position was also medial and the bony wall connected with the osseous enclosures of the nose by short incisive canals, but there was no communication with the oral cavity. The dimensions of the cavity were so considerable (1.6 mm. x 1.35 mm. x 2.2 mm.) that the walls were flattened against various areas of the surrounding compact bone, giving it decidedly the appearance of a sinus. A smooth lining membrane was present. No opening into nose or mouth was found. Professor Meyer concluded that it was a paranasal sinus in a very unusual situation and ealled attention to Underwood's description (07) of a sinus similarly placed in the chimpanzee. The characteristics of the cavity found by Professor Meyer and of the subject of the preceding description are so similar that in the writer’s opinion the two must have had a similar origin. The dimensions of the cavity in Professor Meyer’s speci- men are much greater than possible for an unmodified gap left by the medial nasal and maxillary processes. The probable independence of the two from the nasal cavity at all stages of their developmental history sets them apart from the paranasal sinuses more in appearance than in reality since the evidence points to their origin from a membrane that was once at least in continuity with the nasal lining and similar to it in character. A SUPERNUMERARY PARANASAL SINUS Sill LITERATURE CITED Dursey, E. 1869 Zur Entwicklungsgeschichte des Kopfes. Tiibingen. His, W. 1901 Beobachtungen zur Geschichte der Nasen- und Gaumenbildung beim menschlichen Embryo. Abt. med.-phys. Kg’l. Sichs. Akad. Wiss. Bd. 27. Kanuian, G. 1904 The accessory sinuses of the nose. Jena. Lesouca, H. 1881 The canal naso-palatin chez homme. Arch. de Biol., T. 2. LeDovuste, A. 1906 Traité des variations des os de la face de l’homme. Paris. Merket, F. 1892 Jacobsonsches Organ und Papilla palat. beim Menschen. Anat. Hefte., erste Abt. Meyer, A. W. 1913 Spolia Anatomica, Part 4. Jour. Anat. and Physiol., vol. 48. Onop1, A. 1907 Beitrage zur Kenntniss der Nasennebenhdhlen. Arch. f. anat. Physiol., Anat. Abt. 1908 Nebenhohlen der Nase. Wien. Scuanrrer, J. 1910 The sinus maxillaris and its relations in the embryo, child, and adult man. Am. Jour. Anat., vol. 10. 1910 a The lateral wall of the cavum nasi in man with especial ref- erence to the various developmental changes. Jour. Morph., vol. 21. Unperwoop, A. 1909 An inquiry into the anatomy and pathology of the maxil- lary sinus. Jour. Anat. Physiol., vol. 44. ZUCKERKANDL, E. 1882 Normale und pathologische Anatomie der Nasen- hohle und ihre pneumatischen Anhiinge. Wien. THE ANATOMICAL RECORD, VOL. 19, NO. 6 Resumen por el autor, Clarence Lester Turner. Colegio Wooster. Un medelo de cera de un embrién humano en el estado presomitico. El embrién descrito en el presente trabajo es un embrién humano normal en el estado que precede a la aparicién de los somitas. El autor le designa con el nombre de “‘évulo de Mateer”’, en honor del Dr. H. N. Mateer, de Wooster College, quien le obtuvo y conserv6é. El embrién mide préximamente un milimetro de longitud, y presenta en buen estado de conservacién el disco embrionario, amnios, corion saco vitelino y pedinculo del cuerpo. Es suma- mente notable por estar contenido en un évulo que también encierra un embrién gemelo en vias de degeneraci6n. La serie de dibujos, trazados con ayuda de la cdémara clara, que acompana al texto representa los contornos de todos los cortes, que pasan por el disco embrionario, amnios, saco vitelino, alantoides y pedtinculo del cuerpo. Los cortes median 10 micras de espesor, y los dibujos les representan aumentados 50 didmetros. Si dichos dibujos se aumentan al doble de su tamaio mediante la proyeccién o la fotografia, pueden trazarse sobre placas de cera de un milfmetro de espesor, y el modelo asi obtenido repre- sentard una rescontruccién aumentada uniformemente 100 didimetros en las tres dimensiones. Translation by José F. Nonidez Cornell Medical College, New York AUTHOR'S ABSTRACT OF THIS PAPER ISSUED BY THE BIBLIOGRAPHIC SERVICE, NOVEMBER 1 A WAX MODEL OF A PRESOMITE HUMAN EMBRYO CLARENCE L. TURNER Biological Laboratory of Wooster College EIGHTY-ONE FIGURES INTRODUCTION The presomite human embryo figured in this article has been fully described by Prof. George L. Streeter, of Johns Hopkins University, in a recent monograph (’19) and the twin formation of the same ovum in a shorter article (719). He has designated the embryo as the Mateer Embryo after Doctor H. N. Mateer, of Wooster, through whose efforts it was preserved. It is not the purpose of this paper to attempt to repeat any of the work done, but to present a series of drawings representing all the sections through the embryo and the yolk sac. Such a series of drawings makes it possible for every laboratory in which the wax-plate reconstruction process can be carried out to have a model of this embryo for study. The series should also prove of value to classes in embryology, even though the plane of sectioning is very oblique. The writer is greatly indebted to Doctor Mateer, the owner of the embryo, for a loan of the specimen and for his generous con- sent in permitting this series of drawings to be published. Sev- eral models were constructed, and this series of drawings was prepared in the Biological Laboratory of Wooster College. THE EMBRYO The age of the embryo was placed by Doctor Streeter at about seventeen days. The embryonic shield is approximately 1 mm. long and 0.75 mm. wide at its greatest width. Both the embry- onic shield and yolk sac are surrounded by a thin layer of meso- derm and the entire vesicle is attached to the chorion by the body stalk. All the structures, with the possible exception of the allantois, are apparently quite normal. 373 374 CLARENCE L. TURNER z A. Embryonic shield The embryonic shield is oval in shape, but narrows markedly and bends ventrally in its posterior third. The oval portion is not marked by any uneveness, but the narrow posterior third is — traversed longitudinally by a shallow primitive groove. At the periphery of the shield the ectoderm is continuous, becoming thin and folding over dorsally to form the amnion. B. Amnion and amniotic cavity The line of demarkation between the embryo and the amnion is difficult to distinguish in many of the sections, but the amniotic ectoderm is very thin and is overlaid by mesoderm which binds it loosely to the overlying chorion. Owing to the oblique plane of sectioning, an exaggerated impression of the depth of the amniotic cavity is gained from figure 16. The cavity appears in the reconstruction as a mere cleft except at the extreme posterior end where it comes into contact with the body stalk. C. Body stalk and allantois The body stalk, occurring at the posterior end of the yolk sac, is a fairly compact mass of mesoderm attaching the entire vesicle to the chorion (fig. 22, BD.S.). A few loose strands of mesoderm extend from the body stalk to the chorion, and at one point near the chorion the body stalk is interrupted by a large cavity. Some primitive blood-vessels are found also in the body stalk, but no attempt has been made to represent them in the drawings. The allantois at its proximal end appears as an evagination of the yolk entoderm and within the next few sections becomes a compact round column of cells. The proximal portion of the allantois terminates abruptly and no trace of it can be found for a few sections after which it reappears as a detached segment. In the reconstruction this detached segment shows a marked constriction. ; “I or A WAX MODEL OF A PRESOMITE HUMAN EMBRYO ote D. Yolk sac The yolk sac is much flattened dorsoventrally although its probable normal shape was nearly spherical. As the chorionic vesicle is also flattened in the same direction, it seems likely that both chorion and yolk sac were flattened by their own weight prior to fixing. On the ventral and posterior surfaces of the yolk sac are numerous blood-islands. E. Chorion There are two layers present in the chorion, an inner mesoder- mal layer, which is loose in texture but distinct, and an outer and more compact ectodermal layer. Chorionic villi are attached to the chorionic membrane at intervals. The same layers appear in the villi that'are present in the chorionic membrane, the ventral mass consisting of the mesodermal element and the outer layer a covering of ectoderm. A syncytial and an epithelial layer may be distinguished in the ectoderm, but they have not been shown in the figures. F. Twin vesicle In figure 30 there occur between the large embryo and the chorionic membrane two smaller vesicles which prove to be parts of a second smaller embryo evidently undergoing degeneration. In the larger of these two smaller vesicles a sphere of ectoderm surrounded by mesoderm can be distinguished. The ectodermal sphere enclosing an amniotic cavity is thickened on one side to form the embryonic ectoderm, while the remainder forms an amnion. The second and smaller vesicle is apparently the degen- erating yolk sac of the small twin embryo. Both vesicles are loosely bound to the body stalk and to the chorion by strands of mesoderm. CONSTRUCTION OF MODEL The plane of sectioning is represented by the line AB. The sections were made 10 u thick. A few sections were irregular in thickness or were lost, a number have been twisted and a few 376 CLARENCE L. TURNER broken into fragments. However, by taking the perfect sections as guides, the imperfect sections may be made to conform to the shape as indicated in the perfect sections. With these few excep- tions, the sections are in good condition. All the drawings in this series were made with a camera lucida and all the imperfections are figured as they occur in the sections. A. Irregularities The more outstanding irregularities are listed here with the expectation that they will prove useful for corrections during the construction of a model. The irregularities were checked by making a duplicate set of drawings with carbon paper, using one set for the construction of the model and carefully marking the necessary alterations on the other set of drawings. Section 2 to section 9. The amnion on the right side has col- lapsed or has been pushed in. Section 3 to section 15. ' There is a shrinkage of the mesoderm on the left side of the embryo between the embryonic disk and the yolk sac. Section 5 to section 17. An indentation in the right side of the yolk sac and the overlying mesoderm is evidently an artifact. Section 3 to section 20. The embryonic disk is cracked in most of these sections and in a few the parts have suffered a slight displacement. Section 14 and section 15. Two sections have apparently been lost between these two. Section 17. This one is 40 » thick instead of 10 u thick. Section 16 and section 17. The left half of the embryonic disk is bent ventrally so as to be out of adjustment. Section 23. There is a lateral compression in this section which distorts it somewhat. The foregoing section may be taken as a guide. Section 24. As in section 23. Section 30. The yolk sac membrane and the overlying meso- derm are shrunken and distorted. Section 32 and section 33. These are somewhat broken and A WAX MODEL OF A PRESOMITE HUMAN EMBRYO 377 the pieces displaced, but the general boundaries of the sections are still evident. Section 34. The ventral half of the yolk sac has been dislo- cated toward the left. Section 35. There are two slight breaks in the walls of the yolk sac. Section 37. This section is 20 u thick. Section 40. The walls of the yolk sac are broken at the ventral point and are shifted toward the left in the ventral half. Section 42. The sides of this section are somewhat compressed. Section 46. This section is bent toward the left in its ventral half. Section 47. The sides of this section are slightly compressed and the lower half is dislocated toward the left. Section 48 and section 49. Several sections are missing be- tween these two. Section 50 to section 81. There are many slight irregularities in the shape of the yolk sac, but the shape may be made out by using the following sections as of normal shape: sections 58, 61, 63, 68, and 73. B. Magnification The sections have been cut 10 « in thickness so that a mag- nification of 100 would make the wax sheets 1 mm. in thickness. In the illustrations in this article a magnification of 100 has been used, but the drawings have been reduced one-half for publica- tion. It is suggested that they be stepped up to their original size (twice as large as represented here) when wax sheets of a thickness of 1 mm. may be used. C. Modeling A model such as the one illustrated in plate 1 may be con- structed by the usual Borns’ wax-plate method. A more sub- stantial model which may be handled by students may be con- structed by substituting blotting-paper soaked in equal parts of beeswax and soft paraffin for wax sheets. 378 CLARENCE L. TURNER The structures which serve best as guide lines in building t model are the body stalk and the allantois. The posterior marg of the amniotic cavity can also be used to advantage. BIBLIOGRAPHY Srreerer, Geo. L. 1919 A human embryo (Mateer) of the presomite pe Contrib utions to embryology, vol. 9, Carnegie Inst. Wash. Pub. Ni , 272 . 1919 Formation of single ovum twins. Johns Hopkins Hospita Bulletin, vol. 30, no. 342. = A WAX MODEL OF A PRESOMITE HUMAN EMBRYO 379 EXPLANATION OF PLATE AND FIGURES Plate 1. Model, X 50, representing the amnion cut away on the right side exposing the embryonic shield and the amniotic cavity. The body stalk is represented as bisected to show the allantois. The mesoderm overlying the yolk sac is represented as cut away on the right side to expose the yolk sac. Figs. 1 to 81 This is a series representing all the sections of the ovum in the plane of AB (pl. 1). ABBREVIATIONS ALL., allantois Y.S., yolk sac AM.C., amniotic cavity BL.IS., blood-island AM., amnion CH.V., chorionic villus BD.S., body stalk TW.V., twin vesicle 4 CH.MES., chorionic mesoderm EMB., posterior portion of embryo CH.ECT., chorionic ectoderm Y’.S’, yolk sac of twin PR.GR., primitive groove AM.C.TW.V., amniotic cavity of twin PR.ST., primitive streak vesicle PR.KT., primitive knot EMB.ECT., embryonic ectoderm of MES., mesoderm twin vesicle EMB.D., embryonic disk 380 ae Pomors aanen nensysckes ene SSSS™) HaNUOL “1 AONSUVID 1 ALVId OAUANA NVWOH GLINOSAUd ¥ 40 TAGONW XVM V q . “sia 393 “LO3°HD “A‘HO (a2) “6 "193°aWa “A*ML “ORY 395 THE ANATOMICAL RECORD, VOL. 19, No. 6 403 . a uw = BL.IS. 409 "si "18 si-e@ THE ANATOMICAL RECORD EDITORIAL BOARD Irvine Harpesty Warren H. Lewis Tulane University Johns Hopkins University CLARENCE M. Jackson Cuarugs F. W. McCiure University of Minnesota Princeton University _ Txomas G, Len Wiruram 8. MILtter University of Minnesota University of Wisconsin Freperic T. Lewis FLORENCE R. SaBIn Harvard University Johns Hopkins University GeorceE L. STREETER University of Michigan G. Cart Huser, Managing Editor 1330 Hill Street, Ann Arbor, Michigan VOLUME 20 DECEMBER, 1920—MARCH, 1921 PHILADELPHIA THE WISTAR INSTITUTE OF ANATOMY AND BIOLOGY CONTENTS NO. 1. DECEMBER, 1920 GEORGE 8. HuNTINGTON AND CHarues F. W. McCiure. The development of the veins in the domestic cat (Felis domestica), with especial reference, 1) to the share taken by the supracardinal veins in the development of the postcava and azygos veins and, 2) to the interpretation of the variant conditions of the posteava and its trib- utaries, as found in the adult. Twelve figures (in colors)....................-..24- 1 ievacownRr Anatomy in China. One illustration... 605. ..0ce es csceeesccnsecs 31 EBuGrensr L. Serttes. The effect of high fat diet upon the growth of lymphoid tissue. Hixueenmielres (three plates) sand one! Chart. 26... c nc0ssccds sees ecw iawansescaloces 61 Ivan E. Wauurn. A case of persistent left supracardinal vein with two left spermatic VEINS (QIN TEMS We atiotaan ons dice CAINS so noone Be aoe ee enne eal amen ee eae 95 NO. 2. JANUARY, 1921° E. T. Hstexu. A review of ancient Chinese anatomy. Thirty =OUEMIPUTES! « eieaai saree ee 97 Onriver H. Garsuier. Bladder epithelium in contraction and distention. Nine figures. 129 Waiter N. Hoss. Tracheation of the light-organs of some common Lampyridae. TET AGERE ob bb boone Ad pba w Oe Go 1b oe bo OOD SO CEE See eee 155 Proceedings of the American Society of Zoologists. Eighteenth Annual Meeting...... 163 Proceedings of the American Society of Zoologists. Abstracts....................... 181 Proceedings of the American Society of Zoologists. Constitution, éte. een 3. Proceedings of the American Society of Zoologists. List of Officers ere Mambont ee ae AY! NO. 3. FEBRUARY Juan C. NaNacas. Two cases of monoventricular heart with atresia and transposi- tion of some of the roots of the great vessels. Hight figures (two plates)............ 255 H. E. Jorpan. Further evidence concerning the function of osteoclasts. Five figures. 281 Paut K. Wess anp JAMes BARRETT Brown. A case of independent costal bars of the PeMAULO DN GUsiin TO Ans WM GLU CULES. cctiate a sa clateimeide aia a cae asia ob alaie ae SiGe we esis 297 VinceNT VerMooTEN. A study of the fracture of the epistropheus due to hanging with ~ a note on the possible causes of death. Twelve figures... ............. ccc eee eee 305 P. EB. Linepacx. A case of unilateral polydactyly in a 22-mm. embryo. One figure..... 313 iii iv CONTENTS NO. 4. MARCH Hetey Dean King. A comparative study of the birth mortality in the albino rat and BD TOAR 4. ik cok esc vais KANN ds, Ale cv via-8 OniBl tate Wor ecet ce wih ic eusie eta OO eee ee ee Davin M. Stperstein. The effects of acute and chronic inanition upon the develop- ment and structure of the testis in the albino rat. Five plates (fourteen figures)... . Brapiey M. Parren anp Rees Puaitporr. The shrinkage of embryos in the processes preparatory to'settioning. Hight figures. ..........0...05+ s+. ce+u «ses ssn Cuartes H. Mivier. Demonstration of the cartilaginous skeleton in mammalian FOGWBOR «4. 3 sx bis Ping Fs inla a ape tater OW B75 sss 0 8 We, ao ly Ste ea ee Pere. sae ae ALEXANDER Gipson. Note on a persistent left duct of Cuvier. One figure........ Sista zs Coby tii) Vi t . LITT »; mee - a > by 31 UR eT U - : bsp : ( : . ‘ Batali ahem ts 4" faerie AL efit lena: { imal of! doit) 120 eb Bie a fie DeMaVY Wen MLA Ure | al + aaa HWOTaRE LAY beer 705) ij yy? rea } ireeayt i ae ey fs Ri AE uf Tyas 20 , 4 nai ah ee fo wim ath it BEA) fila yeep ade ty Ho éxhVvie® torts: hs “1 eC R}OF nt dy Poa clad!) + on : Bes i) nite, i acelin gi Epi | Te LL =r i Halt Pos ; os = ¥ ni! EL sry beds git Lt withiy'es 7 f . ‘Bot. Sf milla ting ek ad Pi, Arai Pe dai an ale? @)raly, bu: aa age iy | ae ‘ ise Replies \s wail fir BOM Diet oc, aca beMierstv og. fuaands futsr’ | nia Bread a an ada ae ae ea ' see ee a is r Rei etuls, | iptekattemiam gad Obs cy ! es m+ hide? abl altel itgy a: ib hi), “ a Be cocci bl i PR OV MT Bice >: Th a u eg a ee er PAs ttarett ae 2 Ow east uf ; a our ty per secolc: ‘ >A, fase x ys aA, +) hg 4 ran pit a Resumen por los autores, George 8. Huntington y Charles F. W. McClure, Columbia University y Princeton University. El desarrollo de las venas en el gato doméstico (Felis domestica), con especial mencién de: 1) la participacién de las venas supracardinales en el desarrollo de la posteava y vena azigos, y 2) la interpretaci6n de las condiciones de variaci6én de la post- cava y sus tributarios encontradas en el adulto. Esta investigacién fué comenzada en 1905 con el propésito de determinar el plan venoso ontogénico normal que serviria como base para explicar las variaciones observadas en el gato adulto como resultado de un desarrollo atipico de las venas. El trabajo vi ilustrado con doce figuras en colores, basadas en reconstrue- ciones en cera, y dichas figuras servirin también para explicar las condiciones observadas por los autores en el hombre. Algu- nos de los puntos mas importantes tratados por los autores son los siguientes: 1. La divisién postrenal de la vena postcava se deriva exclusivamente de una parte de las venas subcardinales, partir endo del lado derecho de lo que los autores han llamado el cuello renal, y de las venas supracardinales. Ninguna parte se deriva principalmente de las venas postcardinales. 2.-Las venas azigos se derivan de las supracardinales. 3. Una nueva interpretaci6n sobre el desarrollo de las venas sexuales. 4. Un esquema compuesto que presenta combinados todos los trayectos venosos que pueden aparecer durante la ontogenia. Por medio de este esquema se pueden interpretar los diecisiete tipos en los cuales pueden clasificarse las variaciones de la postcava encon- tradas en el gato y en el hombre. : Translation by José F, Nonidez Carnell Medical College, New York AUTHORS’ ABSTRACT OF THIS PAPER ISSUED BY THE BIBLIOGRAPHIC SERVICE, NOVEMBER 15 THE DEVELOPMENT OF THE VEINS IN THE DOMES- TIC CAT (FELIS DOMESTICA) WITH ESPECIAL REF- ERENCE, 1) TO THE SHARE TAKEN BY THE SUPRA- CARDINAL VEINS IN THE DEVELOPMENT OF THE POSTCAVA AND AZYGOS VEINS AND 2) TO THE INTERPRETATION OF THE VARIANT CONDITIONS OF THE POSTCAVA AND ITS TRIBUTARIES, AS FOUND IN THE ADULT GEORGE S. HUNTINGTON Columbia University AND CHARLES F. W. McCLURE Princeton University TWELVE FIGURES (IN COLORS) This investigation was begun in 1905. In the preceding years we had found that the variations or atypical conditions of the venous system observed by Darrach,! McClure? and others in the adult cat could not all be explained on the basis of the existing knowledge of the development of the veins. We therefore deter- mined to study in detail the normal ontogenetic plan of the veins in the cat, with the hope that we might be able to interpret cor- rectly the variant conditions of the venous system which arose as the result of atypical development of the veins.* We have recently extended our observations to a study of the development of the veins in man, the pig and the rat, and while 1Darrach, W. 1907. Variations in the posteava and its tributaries as observed in 605 examples of the domestic eat. Proc. Amer. Ass. Anat., Amer. Jour. Anat., Vol. 6. * McClure, C. F. W. 1900. On the frequency of abnormalities in connection with the postcaval vein and its tributaries in the domestic cat (Felis domestica). Amer. Nat., Vol. 34. ’ Huntington, G. S., and McClure, C. F. W. 1907 The Development of the Posteava and Tributaries in the Domestic Cat. Proc. Amer. Ass. Anat., Amer. Jour. Anat., Vol. 6. 1 2 GEORGE 8. HUNTINGTON AND CHARLES F, W. McCLURE it has been observed that important generic differences exist in the pig and the rat, the development of the veins in man has been found to resemble more closely that observed in the cat.‘ Although our investigation has been completed, it may be some time before the detailed publication is ready for the press. We have therefore deemed it advisable to publish a preliminary sum- mary of our work in the form of a series of diagrams which illus- trate the normal ontogenetic plan followed by the veins, with especial reference, however, to the share taken by the supracar- dinal system of veins in the development of the azygos vein and of the postrenal division of the postcava in the cat. A brief summary is also given of the potential postcaval variants in the adult cat and man. An explanation of these variant conditions is based on a composite diagram (fig. 12) combining all of the venous pathways which may arise during ontogeny and which are potentially capable of being retained in the adult in atypical individuals. The diagrams which we present are based on a large series of wax reconstructions made after the method of Born, of cat em- bryos ranging between 5 and 45 millimeters in length. They represent a series of critical ontogenetic stages leading from the early primitive venous groundplan common to all vertebrates (fig. 1), up to the conditions obtaining in the adult cat. In constructing these diagrams it was deemed desirable to include all of the main axial yenous channels of the body other than those investigated by us, and we fully appreciate and ac- knowledge that the previous contributions of other investigators, especially those of Rathke,’ Hochstetter* and F. T. Lewis,’ have made this possible. ‘ Huntington, G. S. and McClure. C. F. W. 1920. A series of diagrams ex- planatory of the development of the postcava in the cat, with especial reference to the share taken by the supracardinal system of veins. Proc. Amer. Ass. Anat., Anat. Rec., Vol. 18. *Rathke, H. 1838. Ueber den Bau und Entwicklung des Venensystems der Wirbeltiere. Dritte Bericht tiber das Naturwissenschaftliche Seminar zu Kénigs- berg. Idem. 1832. Abhandlungen zur Bildungs-und Entwicklungsgeschichte des Menschen und der Thiere. Leipzig, T. I. ® Hochstetter, F. 1893 Beitriige zur Entwickelungsgeschichte des Amnioten, III, Siuger, Morph. Jahrb., Bd. 20. 7 Lewis, F. T. 1902 The development of the vena cava inferior. Amer. Jour. Anat., Vol. 1. DEVELOPMENT OF POSTCAVA IN THE CAT 3 The uniform color scheme shown in the figures makes it easy to follow the transformations of the embryonic venous system through the different stages of its development. Only a brief account of each critical stage will be given in the present paper, while a more detailed description will be reserved for a later pub- lication in which the actual reconstructions will be demonstrated on which our observations have been based. Fra. 1. CARDINO-SUBCARDINAL STAGE. This stage of development may be regarded as representing a common groundplan of the vertebrate embryonic venous system. It forms the starting point which is succeeded by a series of modifications gradually leading up to the conditions observed in the adult. In some cases these modifications are brought about by the persistence or atrophy of certain of its component vessels, while in others, modifications arise by the addition of newly- formed vessels to the primary groundplan. The diagrams we present illustrate these modifications of the embryonic ground- plan as observed in the embryo of the eat. The principal vessels of the embryonic venous groundplan con- sist of three pairs of essentially bilateral symmetrical veins, viz. : the precardinal (Prc.) and posteardinal (Pc.) veins which open in common into the sinus venosus through the ducts of Cuvier (D.C.) and the subeardinal (Subc.) veins. The postcardinal veins lie dorsal to the mesonephroi, while the subcardinals lie ventro-medial to the same. Anastomoses between the post- cardinal and subcardinal veins are present and intersubcardinal anastomoses are met with caudal to the origin from the aorta of the omphalomesenteric artery. The sex veins from the gonads (@) open into the subcardinal veins at this stage. The veins of the liver drain for the most part directly into the sinus venosus through the V. hepatica com- munis (V.H.C.) and no connection between the liver circulation and the right subeardinal vein has as yet been formed. The blood collected from the body-walls and mesonephroi by the postcardinals, as well as that carried by the subcardinal veins, is returned to the heart through the ducts of Cuvier (D.C.) in common with that brought from the head region and anterior limb-buds by the precardinal veins. 4 GEORGE 8. HUNTINGTON AND CHARLES F. W. McCLURE Fic. 2. EstaBLISsHMENT OF THE Pars HepaticaA AND Pars SUBCARDINALIS OF THE PosTCAVA, CONSTITUTING THE PRERENAL DIVISION OF THE PosTcAVA IN THE ADULT. The significant features of this stage of development, are the establishment of the prerenal division of the adult posteava, and the beginning replacement of an originally bilaterally symmetrical by a subsequent asymmetrical plan of axial venous organization. As shown by F. 'T. Lewis, the prerenal division of the postcava is formed by the establishment of a communication between the veins of the liver and the right subcardinal vein. The point at which this communication is established with the right subcar- dinal has been previously designated by one of the writers® as the hepato-subcardinal junction (Hep.Subc.Jct.). The portion of the prerenal division of the postcava which lies cranial to the hepato-subeardinal junction may be termed the pars hepatica (P.Hep.). It is formed in situ by a rearrangement and transformation of vascular channels already formed, viz., by the V. hepatica communis, the hepatic sinusoids and by the vas- cular area formed within the caval mesentery. The portion of the prerenal division of the postcava which lies caudal to the hepato-subcardinal junction is known as the pars subcardinalis (P.Subc.), as it is formed largely by a portion of the right subeardinal vein. Slightly caudal to the origin of the omphalomesenteric artery from the aorta, the pars subcardinalis establishes a wide communication with the left subeardinal, through an intersubcardinal anastomosis (Int.Subc.Anast.) and also one with each postcardinal, by the enlargement of one of the anastomoses that exist at this level between the intersubcardinal anastomosis and the postcardinal veins (subeardino-postcardinal anastomoses, Subc.Pc.Anast. (fig. 12)). As the result of these modifications of the early embryonic groundplan, the blood from the region of the body which lies caudal to the intersubcardinal anastomosis (body-walls and meso- nephroi) is now, for the most part, directed from the posteardinal (Pc.2), on both sides of the body, through the subcardino-post- ® McClure, C. F. W. 1906 A contribution to the anatomy and development of the venous system of Didelphys marsupials (L.). Amer. Jour. Anat., Vol. 5, p. 171. DEVELOPMENT OF POSTCAVA IN THE CAT 5 cardinal anastomosis to the prerenal division of the postcava. Also, correlated with these changes, the posteardinals (Pc.2), cau- dal to the intersubcardinal anastomosis, become greatly en- larged, while the segments cranial (Pc. 1) to this anastomosis become reduced and return blood from the body-walls of the thoracic region and from the cranial end of the mesonephroi directly to the heart by the ducts of Cuvier (D.C.). The sex veins still open into the subcardinal veins. Anasto- moses are also still present between the subcardinal and postear- dinal veins, caudal to the intersubcardinal anastomosis, which form part of the mesonephroic circulation. In the region cranial to the intersubcardinal anastomosis, however, the subcardinals soon become associated with the anlagen of the adrenal bodies forming the main venous drainage line of these organs which is retained throughout subsequent stages of development. Fic. 3. FuRTHER TRANSFORMATIONS OF THE PosTCARDINAL AND SUBCARDINAL VEINS WHICH ARE AssOcIATED LARGELY WITH THE GROWTH OF THE MESONEPHROS. SEPARATION OF THE POSsTCARDINAL VEINS INTO A THORACIC AND LumBaR DitvisIon. The originally continuous posteardinals have now become di- vided into a cranial or thoracic (Pc.1), and into a caudal or lumbar (Pc.2) pair of veins. The former collect the blood chiefly from the body-walls of the thorax and from the anterior portion of the mesonephroi, while the latter drain the more caudal regions of the body. The lumbar division of the posteardinal (Pc.2), on each side of the body, now encircles the relatively large mesonephros, both dorsally and medially, so that in reconstructions of the veins at this stage each mesonephros appears to be arched over by or to lie within a great venous basket or trough formed by the post- cardinal vein and its subeardinal anastomoses. The permanent kidneys (K) have migrated craniad from their earlier position ventral to the umbilical arteries and now occupy a position dorsal to the lumbar postcardinals (Pc.2). Cranial to the intersubeardinal anastomosis (/nt.Subc.Anast.) the subcardinal veins, except that portion of the vein of the right 6 GEORGE 8S. HUNTINGTON AND CHARLES F. W. McCLURE side which forms the pars subcardinalis of the posteava (P.Sube.), have become still more closely associated with the adrenal organs so that from now on, we may speak of these veins as the adrenal veins (Adr.). Caudal to the intersubeardinal anastomosis the subeardinal veins have lost their original continuity so that the sex veins, of subcardinal origin, now drain directly into the post- cardinals (Pc.2), as well as into the intersubcardinal anastomosis. The significance of this observation lies in the circumstance that the sex veins at this time are exclusively of subcardinal origin, a condition which is retained in the adult of lower vertebrates, up to and including birds. Fic. 4. Toe EsrasLisHMENT OF THE SUPRACARDINAL SYSTEM or VEINS AND THE RENAL COLLAR. A bilateral and originally symmetrical venous channel develops dorso-medial to the primitive postcardinal and dorso-lateral to the aorta, into which the somatic postcardinal tributaries secondarily drain. This secondary venous channel forms what we have termed the Supracardinal System of Veins (Sprc.). It extends, from the level at which the posterior limb veins unite with the post- cardinals, to a point craniad where it joins that portion of the posteardinals (Pc.1) which alone persists to form the cranial end of the adult azygos (Az.) veins. Between these levels the supra- cardinal veins come to enter into the definite organization of both the adult postcava in its postrenal division and of the azy- gos in its lumbar and part of its thoracic segments, entirely replacing in these districts the primitive postcardinal veins. “Tt is important to note that the supracardinal veins are not in any sense merely synonyms for the dorsal limb of the periure- teric ring described by Hochstetter and others, but comprise a continuous morphologically uniform system of longitudinal venous channels which contribute to the establishment of the adult condition in both the postcaval and azygos areas.’’® The beginning of the establishment of the supracardinal system of veins takes place at a relatively early stage of development, and its cranial extension into the thoracic region is evidence that its appearance is not primarily associated with the cranial migra- tion of the permanent kidneys. Frequent anastomoses occur * Loc. cit., footnote 3. DEVELOPMENT OF POSTCAVA IN THE CAT a between the postcardinals and supracardinals at an early stage of development and, at this time, the anastomoses between the right and left supracardinal veins (intersupracardinal anasto- moses), as shown in figure 4, have not yet been formed. The early anastomoses between the supracardinal and post- cardinal veins soon undergo atrophy and disappear. A large single anastomosis (fig. 4, R.Col.), at about the level of the inter- subeardinal anastomosis, is retained, however, on each side of the body, which permits blood collected by the supracardinals in the lumbar region to reach the heart by way of the prerenal division of the postcava. This anastomosis we have designated as the subcardino-supracardinal anastomosis (R.Col., fig. 4), since, in the later stages, it appears to connect the subcardino-post- cardinal anastomosis with the supracardinal vein. The blood collected by the supracardinal veins which is not directed to the prerenal segment of the postcava through the sub- cardino-supracardinal anastomosis, reaches the heart by way of the ducts of Cuvier (D.C.). The formation of this subcardino-supracardinal anastomosis, at about the level of the intersubeardinal anastomosis, establishes the presence of a circum-aortic venous ring at this point which we have designated as the Renal Collar. In order to appreciate the topographical relations of the renal collar to the main venous channels and the aorta, the reader is referred to fig. 12, a diagram based largely on the reconstruction of a 16 millimeter embryo of the cat. As clearly shown here, the renal collar is formed by the pars subcardinalis of the postcava (P.Subc.), the intersubeardinal anastomosis (Int.Subc. Anast.), the right and left subeardino-posteardinal anastomoses (Sube.Pc.- Anast.), the right and left subcardino-supracardinal anastomoses (Subc.Spre.Anast.), the right and left supracardinals (B and C) and the anastomoses between the supracardinals dorsal to the aorta at this point, at which level the renal veins (R.V.) enter the collar. The sex veins (fig. 4) still join the postcardinals and, in some cases, as shown in fig. 3, they may also open into the intersub- cardinal anastomosis, a condition which is occasionally retained in the adult when mtiltiple sex veins are present. 8 GEORGE 8S. HUNTINGTON AND CHARLES F. W. McCLURE Figure 5. PRoGREssIVE DEVELOPMENT OF THE BILATERAL, SYMMETRICAL SYSTEM OF SUPRACARDINAL VEINS. SEPARATION OF THE SUPRACARDINALS INTO AN AZYGOS AND LuMBAR Division. COMPLETION OF THE CRANIAL MIGRATION OF THE PERMANENT KIDNEYS, THE DEVELOPMENT OF THE RENAL VEINS AND THE ESTABLISHMENT OF THE PERIURETERIC VENOUS RINGs. The supracardinal veins (Sprc.) at first undergo a progressive development during which their bilateral symmetry is retained for a considerable period of time. They soon separate, however, into a cranial or azygos and into a caudal or lumbar pair of veins, from which the azygos veins and a segment of the postrenal divi- sion of the adult posteava are, respectively, derived. The bilateral symmetrical pair of supracardinals in the lumbar region anastomose freely with each other dorsal to the aorta and become greatly increased in size. Blood which they receive from the body-walls through four pairs of dorsal tributaries, and that received by them from the external (Z./1.) and internal iliac (J.J1) veins, now reaches the prerenal segment of the posteava exclu- sively through the right and left subecardino-supracardinal anas- tomoses (lateral portion of renal collar, R.Col. fig. 5), which have become correspondingly enlarged. r Blood collected by the supracardinals in the thoracie region (azygos veins), chiefly from the body-walls, is returned to the heart through the right and left ducts of Cuvier (D.C.), in com- mon with that collected from the head region and anterior limbs by the precardinal veins. The permanent kidneys (K) have completed their migration craniad, and the hilus of each kidney now lies at about the level of the renal collar (fig. 12). After the migration of the kidneys has been completed, the permanent renal veins (R.V.) are formed. These consist at first of a right and left pair of renal veins which extend between the hilus of each kidney and the lateral portion of the renal collar (R.V., fig. 12). The relation of the renal veins to the lateral portion of the renal collar (subeardino-supracardinal anastomosis) is shown in figs. 8 and 9 which are lateral views of the right side of actual recon- DEVELOPMENT OF POSTCAVA IN THE CAT +] structions of the veins of cat embryos measuring, respectively, 16 and 25 mm. in length. Near the hilus of the kidney, each renal vein divides into two branches (fig. 5) and, in some cases, the bifurcation may even extend back to the renal collar. The primitive postcardinal veins (Pc.2, fig. 5) still retain their bilateral symmetry. They unite caudally with the supracardi- nals in the lumbar region and, in addition to blood received from the mesonephroi and gonads, they also receive, in part, that col- lected by the external (H#./1.) and internal iliac (J./1.) veins. Craniad, the postcardinals (Pc.2) also unite with the supracardi- nals (Spre.) through the subcardino-supracardinal anastomosis (lateral portion of renal collar, R.Col., fig. 5) so that the blood eol- lected by the supracardinals and posteardinals in the lumbar region is then conveyed to the prerenal division of the postcava, on each side of the body, through the original subeardino-post- cardinal anastomoses (Subc.Pc.Anast., fig. 12) which constitute the ventral portions of the renal collar. (Compare figs. 5 and 12.) As the result of this cranial and caudal union in the lumbar region between the postcardinal and supracardinal veins, a ve- nous ring has been established on each side of the body, through which the ureter (Ur.) passes. This periureteric venous ring is bounded cranially by the caudal border of the subcardino-supra- cardinal anastomosis (R.Col., figs. 5 and 8 and Subc.Spre.A nast., fig. 12), dorsally by the supracardinal and ventrally by the post- cardinal vein. In the region of the renal collar the ureter (U7r.) lies dorsal to the posteardinal (Pc.2) and sex vein, while further caudad it passes ventral to the postcardinal vein. Finat TRANSFORMATIONS OF THE VEINS (FIGURE 6) WHICH Leap Ur To THE ConpITIONS FounpD IN THE ADULT Cat (FIGURE ia). The primary bilaterally symmetrical plan of the supracardinal veins in the lumbar region (fig. 5, Spre.) is soon replaced by an asymmetrical one (fig. 6). This change is initiated by a reduction of the left side of the cireum-aortic venous ring, involving its su- pracardinal component and of the portion labelled R.Col., fig. 6, while the corresponding channels of the right side enlarge. This 10 GEORGE 8S. HUNTINGTON AND CHARLES F. W. MeCLURE change is finally followed by the complete atrophy of the left side of the renal collar, or strictly speaking, of the subcardino- supracardinal anastomosis of the left side. In consequence of this change, the blood collected by the left supracardinal vein is therefore directed toward the right supra- cardinal through the intersupracardinal anastomoses and, to- gether with the blood collected by the right supracardinal, now reaches the prerenal division of the posteava by way of the right side of the renal collar. Fig. 6 represents a stage in which the left side of the renal collar is undergoing atrophy, while in fig. 7, the left side of the collar has completely disappeared. While it may be said that the right supracardinal vein is chiefly concerned in the formation of a portion of the postrenal division of the posteava, the supracardinal vein of the left side is also involved. The left supracardinal (fig. 6) does not, as one might suppose, undergo complete atrophy in situ, but rather is drawn into or fuses with the vein of the right side, at least in the cadual half of its extent. This portion of the posteava derived from the supracardinals (pars supracardinalis, fig. 7) may therefore be re- garded as being formed largely through a fusion of both supra- cardinal veins, and not from a single vein on the right side, as is usually described to be the case, although the latter furnishes the major contribution. It has been stated above that after the complete atrophy of the left side of the renal collar, all of the blood collected by the supra- cardinals in the lumbar region reaches the prerenal division of the posteava through the right side of the renal collar. One of the most interesting observations we may have made regarding the development of the veins in the cat, is that the right side of the renal collar typically enters directly into the formation of a defi- nite portion of the postrenal division of the postcava, which we | have designated the pars renalis (P.Ren.) of the postcava, on account of its relation to the entrance of the renal veins (R.V., fig. 7). The manner in which this is brought about can best be illustrated by a series of actual reconstructions of the veins which show the relations that the right side of the renal collar bears to DEVELOPMENT OF POSTCAVA IN THE CAT 11 the prerenal division of the postcava and to the supracardinal and posteardinal veins. The reconstructions referred to are repre- sented by figs. 8, 9, 10 and 11 which are lateral views of the veins of the right side of cat embryos measuring 16, 25, 29 and 45 mm., respectively, in length. In the 16 mm. embryo (fig. 8) it is seen that the right periureteric venous ring is still complete and that blood from the caudal region of the body can reach the prerenal division of the postcava by two routes, viz., by way of the right postcardinal vein (Pc.2),into which the sex veins open, and by way of the right supracardinal vein and right side of the renal collar. This latter route is the permanent one typically retained in the adult and constitutes the postrenal division of the postcava. In the 16 mm. embryo, from which this figure was drawn, the left side of the renal collar is also intact, so that blood from the left side of the body can also reach the prerenal segment of the postcava through a corre- sponding set of veins (fig. 5). In the 25 mm. embryo (fig. 9) both posteardinal veins (Pc.2) have given up their caudal connection with the external and in- ternal iliac veins and the left side of the renal collar has also com- pletely disappeared, so that blood from the hind limbs and lum- bar region of the body, now reaches the prerenal division of the postcava solely through the fused supracardinals and the right side of the renal collar. The right postcardinal vein opens into the ventro-caudal border of the renal collar (figs. 9 and 12) and returns blood to the prerenal segment of the posteava, which it receives exclusively from the right mesonephros and from the right gonad through the sex vein. The venous arch formed by the fused supracardinals and right side of the renal collar, in figs. 8 and 9, is a marked and constant character of these veins in the earlier stages, a condition, however, which is later changed. This change consists of a straightening out of the arch formed by the supracardinals, and of an actual elongation, in a cranio-caudal direction, of the right side of the renal collar. Fig. 10, of a 29 mm. embryo, shows the renal collar in the process of elongation, while in fig. 11, of a 45 mm. embryo, the elongation has been completed and the collar assumed the 12 GEORGE S. HUNTINGTON AND CHARLES F. W. McCLURE condition permanently retained in the adult. As a result of this elongation, the point at which the right postcardinal (Pc.2) opens into the renal collar becomes gradually shifted caudad, so that the right posteardinal finally opens into the postcava (renal collar) somewhat caudal to the points of origin of the right renal veins (R.V., fig. 11). The blood from the right gonad reaches the right postcardinal through the sex vein of subcardinal derivation. After the com- plete degeneration of the right mesonephros, the original drainage line of the right posteardinal is occupied exclusively by that of the right sex vein (figs. 8, 9,10, 1l and 7). The original point of connection of the right postcardinal with the renal collar, although shifted caudad, is therefore retained in the adult as the point at which the postcava is joined by the right sex vein. This point, as we have seen, is the ventro-caudal border of the right embry- onic renal collar. In figs. 6 and 7, the elongation of the right side of the renal collar is represented as having taken place. Considerable variation has been found to exist in the adult cat, as regards the relation of the points at which the right sex and the right renal veins open into the postcava. This varia- tion can undoubtedly be explained, in some cases, at least, on the ground that the extent to which the right side of the renal collar elongates in a cranio-caudal direction may differ in indi- vidual cases. The opening of the right sex vein into the posteava, caudal to that of the right renal vein is, however, now easily explained, on the basis of an elongation of the right side of the renal collar. Furthermore, it is plainly evident that the right postcardinal vein does not, in the slightest degree, as hitherto sup- posed, enter into the formation of the postrenal division of the post- cava which, as we have seen, is formed by the supracardinal veins (P. Spre.) and by the right side of the renal collar (P. Ren., fig. 7). As far as the postcava and its tributaries are concerned, there still remain to be considered further changes regarding the right and left renal veins and the sex vein of the left side. It has been stated above that after the migration of the kid- neys has been completed, the permanent renal veins are formed. These consist at first of a right and left pair of renal veins which DEVELOPMENT OF POSTCAVA IN THE CAT 13 extend between the hilus of each kidney and the lateral portion of the renal collar (Subc. Spre. Anast., fig. 12). The condition which obtains on the right side of the body in the adult, appears to be brought about by the persistance of the more ventral of the two embryonic renal veins and the complete atrophy of the other (fig. 7). This single right renal vein then retains its connection with the pars renalis of the postcava which is formed from the right side of the renal collar (fig. 7). The relations of the postcardinal vein, into which the sex vein opens, and of the two embryonic renal veins to the renal collar are originally the same on both sides of the body (figs. 5 and 12). When the left side of the renal collar (subcardino- supracardinal anastomosis) atrophies, however, the more ventral of the two embryonic renal veins and the left postcardinal vein continue to retain their connection with the left subcardino-post- cardinal anastomosis. The result is that the latter, together with the more ventral of the two embryonic renal veins, then forms the left renal vein of the adult, while the left postcardinal vein, after the complete degeneration of the mesonephros, serves as the pathway through which the left sex vein opens into the left renal vein (compare figs. 6 and 7). On the basis of their development, the presence in the adult cat of two, three or even four renal veins on the same side of the body is now not difficult to explain. When more than two renal veins are present this condition is undoubtedly related to the extent to which the bifurcation of the original embryonic renal veins is involved. It has long been erroneously stated in text-books of embry- ology that the postcardinal veins in the thoracic region give rise to the azygos veins. The history of the development of the azygos veins in the cat is illustrated in figures 3 to 7, inclusive, in which it is shown that they are derived chiefly from the supra- cardinals and that in the adult cat only the proximal end of the right azygos near the duct of Cuvier, is derived from the post- cardinal vein (Pc.1). As stated at the beginning of this paper the chief object of our investigation was to establish the normal ontogenetic plan 14 GEORGE S. HUNTINGTON AND CHARLES F. W. McCLURE of the veins in the cat, with the hope that we might be able to interpret correctly the variant conditions of the venous system which arose as the result of atypical development of the veins.'® On the basis of this investigation we have therefore constructed a composite diagram (fig. 12) of the embryonic veins of the cat which make their appearance, at one time or another, during the course of ontogeny. We have already shown in the preceding pages how some of these embryonic veins function only temporarily and then dis- appear, while others persist and are carried into the adult stage. When we meet with a venous variant in the adult it is therefore due, in the majority of cases, to the occurrence and persistence of some modification of the ontogenetic plan ordinarily followed by the veins, which is carried into the adult. It is also evident when such atypical conditions arise, that their explanation lies in the determination of the normal potential embryonic pathways which may have been concerned. Also, if our composite diagram of the embryonic veins is correct, we should not only be able to interpret the atypical conditions already found, but should also be able to predict those which are potentially capable of occurring in the adult cat. On the basis of this composite ontogenetic plan of the veins we have been able to classify under 17 main Types the variant conditions of the posteava which may occur in the adult cat. We have also found that all of the postcaval variations thus far observed in man by other investigators, as well as by ourselves, can be classed under these same types. If we return to the composite diagram (fig. 12) we see that the embryonic veins which typically enter into the formation of the adult posteava are the right supracardinal (B), the right sub- cardino-supracardinal anastomosis (Subc.Spre.Anast.), the right subeardino-postcardinal anastomosis (Subc.Pc.Anast.), the inter- subeardinal anastomosis (Int.Sube.Anast.), the pars subeardi- nalis (P.Subc.) and the pars hepatica (P.Hep.) of the postcava. 1° Huntington, G. S. and McClure, C. F. W. 1907 The interpretation of variations of the postcava and tributaries of the adult cat, based on their devel- opment. Proc, Amer. Ass. Anat., Amer. Jour. Anat., Vol. 6. DEVELOPMENT OF POSTCAVA IN THE CAT 15 On the other hand, it is plain that the persistence in the adult of the left supracardinal (C), or of the right posteardinal (A), or left posteardinal (D), either singly, in combination with one an- other, or with the right supracardinal vein (B) to form the post- renal division of the postcava, would constitute an atypical con- dition of the veins. In addition to the typical condition of the postcava, mentioned above, which we may speak of as Type B, there are therefore 14 other combinations potentially possible between the right and left postecardinals and the right and left supracardinals in the lumbar region, any one of which may per- sist in the adult and constitute a variant condition of the post- renal division of the posteava. These J'ypes are as follows (fig. 12): 1. Type A, persistence of right posteardinal (A) vein. 2. Type AB, persistence of right postcardinal (A) and right supracardinal (B) veins. Right periureteric venous ring. 3. Type ABC, persistence of right postcardinal (A), right supracardinal (B) and left supracardinal (C) veins. Right periureteric venous ring. 4. Type ABCD, persistence of right postcardinal (A), right supracardinal (B), left supracardinal (C) and left posteardinal (D) veins. Right and left periureteric venous rings. 5. Type ABD, persistence of right postcardinal (A), right supracardinal (B) and left posteardinal (D) veins. Right peri- ureteric venous ring. 6. Type AC, persistence of right postcardinal (A) and left supracardinal (C) veins. 7. Type ACD, persistence of right posteardinal (A), left supra- cardinal (C) and left posteardinal (D) veins. Left periureteric venous ring. 8. Type AD, persistence of right (A) and left posteardinal (D) veins. 9. Type BC, persistence of right (B) and left supracardinal (C) veins. 16 GEORGE 8S. HUNTINGTON AND CHARLES F. W. McCLURE 10. Type BCD, persistence of right (B) and left supracardinal (C) and left posteardinal (D) veins. Left periureterie venous ring. 11. Type BD, persistence of right supracardinal (B) and left posteardinal (D) veins. 12. Type C, persistence of left supracardinal (C) vein. 13. Type CD, persistence of left supracardinal (C) and left posteardinal (D) veins. Left periureteric venous ring. 14. Type D, persistence of left postcardinal (D) vein. With the exception of Types ABD, ABCD and BCD, all of the above-mentioned Types have been observed by us or by others, either in the adult cat or man. Type ABCD, however, has been figured by Hochstetter™ as occurring in Erinaceus europaeus. It is interesting to note in Types A, D and AD (fig. 12), that the lateral portion of the renal collar (subcardino-supracardinal anatomosis, Sube. Sprc.Anast.) does not enter into the formation of the postrenal division of the postcava, and, furthermore that an atypical condition invariably results whenever the posteardi- nal veins persist in the adult. This further emphasizes the fact, already mentioned, that the right posteardinal vein does not, in the slightest degree, typically enter into the formation of the postcava in the adult cat. Three other types of variations of the postcava are met with which may result from atypical development of the embryonic veins. These are as follows (fig. 12): 15. Absence of the Prerenal Division of the Postcava and Substi- tution for the Latter in the Thoracic Region, of the Right or Left or of Both of the Supracardinal (azygos) Veins, as the Direct Cranial Continuation of the Postrenal Division of the Postcava. The postrenal division of the postcava, in such cases, is usu- ally formed by the right (Type B), the left (Type C) or by both of the supracardinal veins (Type BC). It would be quite pos- sible, however, for the postcardinals (A and D) in the lumbar region also to persist in place of, or in combination with the supracardinal veins (B and () but, as far as we are aware, such a condition has not been observed. " Loe cit., Taf. 23, fig. 24. DEVELOPMENT OF POSTCAVA IN THE CAT 17 * Cases in which the prerenal division of the postcava (pars he- patica and pars subeardinalis) is wanting, are undoubtedly due to the circumstance that, for some reason or other, the embryonic liver circulation has not been tapped by the right subcardinal vein (figs. 1 and 2). Blood from the liver therefore continues to reach the heart throughout all subsequent stages of development, as in fig. 1, through the V. hepatic communis (V.H.C.) which serves as the hepatic revehent vein in the adult. In variants of this character in which the postrenal division of the postcava is formed by the supracardinal veins, the renal veins open into the latter and also, on each side of the body, the sex vein opens into the renal vein. This is due to the persistence of the lateral portion of the renal collar on each side of the body, into which the renal and sex veins open, the latter through the postcardinals, and the retention of its connection only with the supracardinal vein. In such cases the lateral portion of the renal collar does not enter into the formation of the postcava and, as the pars sub- cardinalis of the posteava is wanting, the ventral portion of the renal collar (subcardino-posteardinal anastomosis, Subc.Pc. Anast.), has not been formed, or, at least, has not been carried into the adult stage. The occurrence of variants of this character in the adult cat and man, serves as a complete confirmation of its presence in the embryo and of the morphological unity of the supracardinal system of veins. 16. Persistence of the Cardinal Collateral Veins (The Marsupial Type of Postcava). With very few exceptions among marsupials, the postrenal divi- sion of the posteava lies ventral to the aorta and its iliac tributa- ries which is the reverse of the conditions usually observed in pla- cental forms. This has been found by one of the writers to be due to the circumstance that the postcava in the lumbar region is formed in marsupials by a fusion of two veins which takes place ventral to the aorta, and which have been termed the Cardinal Collateral Veins. 12 McClure, C. F. W., loc. cit., 1906. 18 GEORGE 8. HUNTINGTON AND CHARLES F. W. McCLURE Veins occupying a similar position to the cardinal collateral veins of marsupials are present in the embryo of the cat. They may form an extensive plexus of vessels which connect with the supracardinals dorsally, and encircle the aorta ventrally between the renal level and the origin from the aorta of the umbilical arteries. In the diagram (fig. 12) only the more caudally situ- ated portion of the cardinal collateral system of veins (CC) is shown, where they form a venous ring with contiguous venous channels, on each side of the body, through which the umbilical artery passes. These rings are very constant in character in this location and the ventral or cardinal collateral portion of the ring has been found to persist both in the adult cat and man, as the sole pathway through which blood can reach the posteardi- nals or supracardinals, as the case may be, from the external (E.J1.) and internal iliac (J./1.) veins. Cases in which the car- dinal collateral veins have persisted in the adult are very rare and we know of only three instances, two in the cat and one in man, in which this condition has been observed. In the marsupials, on the other hand, it is the ventral or cardinal col- lateral (C.C.) element of this cireum-umbilical venous ring which normally enters into the formation of the posteava in this region, while the dorsal element of the ring disappears.” As far as we have observed, the cardinal collateral veins are very evanescent in character and do not play any especially sig- nificant rdle in the normal transformations of the embryonic veins in the eat. For this reason we have omitted them, for the most part, from our diagrams in order to avoid complications and too much detail. 17. Persistence of the Renal Collar in the Adult. We know of three cases in man and none in the eat, in which a complete cireum-aortic venous ring, the embryonic renal col- lar, has persisted in the adult. Now that we know the potential possibilities of the veins in this region, however, other cases of this type of variant will undoubtedly be found, not only in man, but also in the cat. Instanees in the adult in which the left renal vein passes dorsal to the aorta before joining the postcaval vein are also easily ex- 13 McClure, C. F. W., loc. cit., 1906, p. 203. DEVELOPMENT OF POSTCAVA IN THE CAT 19 plained. This is brought about by the retention of a connection between the lateral portion of the renal collar on the left side and the supracardinal veins, and the atrophy of the anastomosis between the pars subeardinalis of the postcava and the left post- cardinal vein (subeardino-postcardinal anastomosis). The presence of multiple sex veins on one or both sides of the body, or of an anastomosis between the sex veins of opposite sides in the adult, has not proved a difficult matter to interpret, but may best be considered in detail at another time. Variants of this character are largely related, though not always, to atypical conditions of the embryonic subeardinal veins. No instance has yet been found, however, in which the continuous subcardinal channels in the lumbar region, as met with in the embryo (fig. 2), have been carried into the adult stage. While for convenience of description we may classify the poten- tial variant or atypical conditions of the adult postcava into 17 distinct types, we fully appreciate that combinations of these types may also occur. The circumstance, however, that we now possess a classification based upon a definite ontogenetic plan of the veins, seems to be a distinct advance over our former knowl- edge, as it not only permits us to interpret the atypical condi- tions of the posteava thus far observed, but also enables us to predict others which are potentially capable of occurring, and which still remain to be found. THE ANATOMICAL RECORD, VOL. 20, NO. 1} COLOR SCHEME OF FIGURES Blue: Cardinal System of Veins and their Derivatives. Red: Subeardinal System of Veins and their Derivatives. Brown: Supracardinal System of Veins and their Derivatives. Green: V. hepatic communis and Ductus Venosus Arantii. Yellow: Subeardino-Supracardinal Anastomosis (lateral portion of Renal Collar) and Renal Veins. Lavender: Cardinal Collateral Veins. FIGURES Figs. 1 to 7, inclusive, diagrams illustrating the development of the veins in the cat (Ventral Views). Figs. 8 to 11, inclusive, lateral views of reconstructions of the right side of the renal collar and of the right postcardinal, right supracardinal and right sex veins in cat embryos measuring, respectively, 16, 25, 29 and 45 millimeters in length. Pig. 12. Composite diagram of the embryonic veins of the cat. ONTOGENETIC DIVISIONS OF ADULT POSTCAVA (FIG. 7) Pars Hepatica, P. Hep. } are Pars Subeardinalis, P. Sube. Frerenal Division Pars Renalis, P. Ren. \ nN were ] Pars Supracardinalis, P. Spre. { Postrenal Division 20 EXPLANATION OF FIGURES ABBREVIATIONS A., Right Posteardinal Vein (Lumbar Division) Adr., Adrenal Vein (Adrenal Organ in fig. 7) Ao., Aorta Az., Azygos Vein B., Right Supracardinal Vein (Lumbar Division) C., Left Supracardinal Vein (Lumbar Division) C.C., Cardinal Collateral Veins (fig. 12) CJl., Common Iliae Vein C.J., Common Jugular Vein C.S., Coronary Sinus D., Left Posteardinal Vein (Lumbar Division) D.C., Duct of Cuvier D.V., Ductus Venosus Arantii E.J1., External Iiae Vein E.J., External Jugular Vein G., Gonad Hep.Subc.Jct., Junction. IJ1., Internal Iliac Vein. I.J., Internal Jugular Vein Int.Subc.Anast., Intersubeardinal An- astomosis. K., Kidney (Metanephres) LJn., Left Innominate Vein Hepato-Subcardinal P.Hep., Pars Hepatica of Posteava P.Ren., Pars Renalis of Posteava P.Subc., Pars Subeardinalis of Post- cava P.Spre., Pars Supracardina is of Post- cava Pc., Pesteardinal Vein Pc.1., Posteardinal Vein (Thoracie Division) Pc.2., Posteardinal Vein (Lumbar Division) Pre., Precardinal Vein Previ., Precava R.Col., Subeardino-Supracardinal An- astomosis or lateral portionof Renal Collar in figs. 4 and 5 and on left side in figs. 6 and 7 RJn., Right Innominate Vein R.V., Renal Vein Scl., Subelavian Vein Spre., Supracardinal Vein Subc., Subeardinal Vein Sub. Pc.Anast., Subeardino-Pestear- dinal Anastomosis Sube.Spre.Anast., Subeardino-Supra- cardinal Anastomosis S.V., Sex Vein Ur., Ureter V.H.C., Vena Hepatica Communis 23 Reval Collar Mesonephroic drainage 10 -Subc. Jet. SexV. \ Remmant of Nesonephroic drainage (Pe. 2.) im) Postcard:nal!Pe.1) Supracerdinal (Azygos) Adr. Renal Collar Postcardinal (Pc.2) Tlio- LumberV. CaudalV. 12 30 Resumen por el autor, E. V. Cowdry, Peking Union Medical College, Peking, China. La Anatomia en China. El presente trabajo es una breve relacién de un estudio sis- temitico sobre las condiciones presentes y necesidades futuras de la ciencia de la Anatomia en China. Después de mencionar los factores principales en la introduecién de la Medicina moderna en dicho pais, el autor publica una lista de todas las Escuelas médi- cas que funcionan actualmente en China, asi como lo nombres de los anatémicos que ensenan en ellas, llamando la atencién sobre la falta de anat6micos que puedan dedicar todo su tiempo a la ensenanza y la dificultad para obtener material para la disec- cion. También incluye en su trabajo la lista de socios, constitucién y programa de la primera sesién de la Asociacién Anat6émica y Antropol6gica de China y discute la influencia de esta Asociacién sobre el desarrollo de la Anatomia en el pais mencionado. Translation by José F. Nonidez Cornell Medical College, New York THE ANATOMICAL RECORD, VOL. 20, No. 1 First photograph of the Anatomical and Anthropological Association of China iken at the entrance to the Anatomical Laboratory of the Peking Union Medical College of the Rockefeller Foundation on February 27, 1920. AUTHOR'S ABSTRACT OF THIS PAPER ISSUED BY THE BIBLIOGRAPHIC SERVICE, DECEMBER 6 ANATOMY IN CHINA E. V. COWDRY Anatomical Laboratory of the Peking Union Medical College of the Rockefeller Foundation ONE FIGURE INTRODUCTION The following agencies are concerned in the development of modern medicine in China: : 1. Foreign Missionaries: Most of the pioneer work has un- doubtedly been accomplished through the energy and devotion of foreign missionaries who have labored faithfully in the face of prejudice and superstition. In 1913 the China Medical Mis- sionary Association passed the following resolutions which make their purpose quite clear: 1). That in establishing medical colleges and hospitals our sole object is to bring the blessings of healing to the souls and bodies of the people of China, and to give a thorough training in medicine and sur- gery to young men and women of education and intelligence, enabling them as fully qualified doctors to be of the highest service to their country. 3 2.) That we have no desire to create permanently foreign institu- tions, and that our aim and hope is that these medical colleges will, gradually and ultimately, be staffed, financed, and controlled by the Chinese themselves. 3). That we desire to bring our teaching work into line with the regulations of the Ministry of Education, and in all ways to co-operate with and assist the Government of the Republic in medical education, so that a strong and thoroughly equipped medical profession may be established in this great land. 2. Foreign Agencies of Non-Missionary Character: The British Government has materially aided in the development of medicine in South China. It has been particularly successful in securing the support of wealthy Chinese in founding the Medical Depart- 33 34 E. V. COWDRY ment of the University of Hongkong. Even the President of China showed his interest in the enterprise by establishing the “Ta Tsung T’ung Ch’uan Hsueh Fei” fellowship for university students. Unfortunately the war has depleted the Colonial Treasury, and, I have been told, the Chinese have shown less interest in the enterprise following the award of the German rights in Shantung to the Japanese. The school buildings, which are up-to-date in every particular, are situated on the side of the mountain and command a fine view of the harbor. The equip- ment is excellent, the surroundings the finest and most healthful along the South China coast, the facilities for preliminary educa- tion good; all that is needed to make the medical department one of the best and most attractive in China is an adequate fulltime staff. The Professor of Anatomy teaches also clinical surgery and the Professor of Physiology acts as Dean and teaches, in addition, microscopic anatomy. Members of the faculty are allowed to practise as consultants. To keep abreast of recent advances in medical education arrangements must be made for the maintenance of at least three full time men in each of the departments of Anatomy, Physiology and Pathology. The future of this institution is very bright in view of the broad minded attitude of the authorities, that it is the purpose of the Medical School to serve the whole of South China, not merely the Colony and Chinese of British nationality. The Germans made good beginnings in Shanghai and Tsingtau which were interrupted by the war. The Shanghai School was located in the French Concession and was maintained in close affiliation with a strong engineering department which was financed largely by Krupp interests. After the seizure of the buildings, with part of the general equipment and library, by the French authorities, the teaching was transferred to the Tung Chi and Paulum Hospitals in the International Settlement. Most of the German instructors were deported and the remainder for- bidden to enter either of these hospitals, so that at present most of the actual instruction is given to the students by two German doctors in private houses just across the street at Nos. 24 and 25 Burkill Road. There are 120 students and about 40 women ANATOMY IN CHINA 35 in the Nurses Training School. The institution is now called the Tung Chi Medical School and is apparently being main- tained by the Chinese Government. Provision has been made for premedical and engineering work at Woosung and I have been told that the Peking Government has granted a sum of $300,000 for the construction of new buildings for these departments. Most of the information which I obtained at the office of the Com- missioner of Foreign Affairs in Shanghai regarding Tung Chi proved to be unreliable and misleading. The other school, in Tsingtau, has been taken over by the Japanese authorities but is not being operated by them. The Japanese Medical School in Mukden is unquestionably one of the best medical institutions in China. Its strength lies in its full time staff. It publishes a volume of researches each year which will bear careful study. While it is actually owned by the South Manchuria Railway it is nevertheless under strict governmental control. Hospitals are also maintained in nearly all of the large cities by an influential Japanese philanthropic society under the presidency of the distinguished statesman, Count Okuma. In view of the further consideration that a large number of Chinese physicians have received their training in Japan, it is not surprising that the Japanese exercise consider- able influence in medical education. Several American Universities have undertaken medical work in China. In the Yale-Hunan Medical School at Changsha a special attempt has been made to codperate with the Chinese. This school has made headway in spite of its inaccessibility and the chronically unsettled condition of the province. The land and equipment of the Harvard Medical School in Shanghai was taken over in 1916 by the Rockefeller Foundation. The China Medical Board of the Rockefeller Foundation is responsible for the most recent developments in medical educa- tion. Its purposes are clearly set forth in a letter, under date of March 15, 1915, from Mr. John D. Rockefeller, Jr., to the various missionary societies in Great Britain and the United States as follows: 36 E. V. COWDRY 1. To assist Missionary Societies to strengthen their medical schools and hospitals by providing equipment and other facilities, and by mak- ing annual grants, as may be found expedient, for the support of phy- sicians and nurses, selected by the respective Missionary Boards, sub- ject only to the Foundation’s approval of the professional qualifications of the appointees. 2. With the consent of the Missionary Boards, to reorganize and expand existing medical schools, with their hospitals, and to support these, wholly or in part, from its own funds. 3. To aid other medical schools that are not strictly missionary. 4. To establish, equip and support new medical schools and hos- pitals. In choosing its agents, physicians and nurses for independent schools or hospitals, the Foundation will select only persons of sound sense and high character, who are sympathetic with the missionary spirit and motive, who are thoroughly qualified for their work pro- fessionally, and who will dedicate themselves to medical ministration in China. Beyond these qualifications, the Foundation cannot prop- erly impose tests of a denominational or doctrinal nature, such as are deemed desirable by Missionary Boards for their own medical mis- sionaries or agents. The Board originally planned to establish two new medical schools, one in Peking and the other in Shanghai, but has recently decided to devote all its energies to the foundation and mainte- ance of one really first class school in Peking. To this end $7,000,000 have already been expended on buildings and equip- ment: The yearly budget is a large one owing to the fact that the entire staff is on a full time basis. It already amounts to about $750,000 per annum and will probably reach a million in the near future. The China Medical Board has also contributed generously toward the assistance of other medical schools and hospitals. Up to the end of 1918 payments totalling $676,889.70 were made to thirty-one institutions.! 3. The Chinese themselves.2. The work of the Chinese Govern- ment should be given careful attention. The Army Medical 1 Roger S. Greene, The Rockefeller Foundation in China, ‘ Asia,’’ November, 1919. ? “The Chinese government has discovered that it has a saving’s account with a credit balance of five million dollars in the Russo-Asiatic Bank. The amount was placed there by the old Imperial Board of Education in Manchu days, when the department of education was one of the wealthiest in the govern- ment. Owing to the confusion incident to the change of regime, and the disap- pearance of the officials who deposited the money, the account was entirely lost sight of.’’ (North China Star, May 13, 1920.) ANATOMY IN CHINA 37 School, the Naval Medical School, the National Medical College and the five Provincial Medical Schools constitute a creditable foundation on which to build. They represent a conscientious attempt on the part of the Chinese to assume responsibility for their own needs in the way of medical education. The late Presi- dent, Yuan Shih-Kai, declared, that ‘“‘For a country to be strong and prosperous it is essential that its citizens be healthy.”’ It is important that these medical schools should grow rapidly and become the back bone of the nation. Up to the present they have received very little foreign support and it is doubtful whether they will accept any. The Director of one of them told me that open codperation with a foreign institution might have a bad effect upon his annual budget (owing to antiforeign feeling). Some medical missionaries, on the other hand, take but little interest in Chinese schools because they see in them no oppor- tunity for evangelistic work. One doctor dismissed the question by saying that ‘‘it is difficult to coéperate with them because they are only heathens any way.” The case of the Kung Yee Medical College is instructive. This school belongs to a group of Chinese in Canton. It has excellent buildings in a fine location, and, until recently, had a fairly com- plete staff. The instruction given is of a relatively high grade. The educational policy of the institution was under the control of an executive committee in which foreign influence predomi- nated. A proposal was made to become affiliated with the Can- ton Hospital (Missionary) which was apparently acceptable to all parties. At the last moment, unexpectedly and in an uncon- stitutional way, the Chinese members of the Kung Yee Society refused to ratify the agreement. The missionary element in Canton is almost unanimous in declaring that they can have no more confidence in the Kung Yee Society and that further negotiations are impossible. Affiliation has now been effected between the Canton Hospital and the Canton Christian College. The Chinese schools have been unable to keep pace with the rapid advances in the foreign controlled institutions, which tend to attract the best students. With a depleted treasury the Chi- 38 E. V. COWDRY nese may prove reluctant to make large expenditures to accom- plish something which the foreigners will do for them gratis. Very skillful and diplomatic assistance is called for. As a rule the buildings and equipment are adequate for the present needs. It might be possible, however, to improve the library accommoda- tions and to strengthen the teaching staff. The addition of one or two really well trained Chinese, who have travelled abroad, with a liberal salary guaranteed, to one of these colleges would soon react beneficially upon the whole institution. It is also desirable that members of the staff, already under appoint- ment, should be given an opportunity to travel. Above all, research work should be encouraged. It might be a good idea to try the European policy of offering prizes and medals for the best work done. Perhaps the President of China would himself consent to make the awards. The underlying difficulty, however, is the deeply rooted con- viction, handed down for forty centuries, that the medical pro- fession is but a fourth or fifth rate occupation. The sentiment of a nation like China cannot be changed over night nor yet in fifty years’ time, but a beginning has been made in Peking, for example, where the splendid buildings of the Rockefeller Founda- tion will surely lead people to doubt whether, after all, the medical profession is so very degrading. The raising of a despised trade to the level of a dignified profession requires long and sustained effort throughout the country, but until it has been accomplished, we cannot hope for any real development of modern medicine in China. The people generally look upon disease and sickness in an apathetic and fatalistic way, believing that it is a visitation of providence in punishment for their transgressions, or at any rate that it is the will of God, as our forefathers thought in Europe several hundred years ago and some continue to think. While such views prevail there can be no real progress. This tendeney to shift the responsibility from their own shoulders is character- istic of the Chinese in all their dealings, and will be very difficult to correct. ‘They are handicapped also by certain customs like foot binding, and the binding of the breasts in young women ANATOMY IN CHINA 39 before marriage, which they still practice blindly, having forgot- ten their origin and not troubling to ask the why or the wherefore. Efforts to introduce modern medicine in China will be unavail- ing unless a nation-wide campaign is carried on by Chinese and foreigners alike for the education of public opinion. At present the graduates of the schools which have been established are regarded with indifference or active distrust by the vast majority of their countrymen. It is particularly difficult for those of them who have to go into the interior, away from the thin film of foreign influence, to live up to their new ideals, in the face of universal incredulity and without sympathy or assistance of any kind. A beginning is being made from several angles without proper coérdination and on a very small scale. Professor John Dewey of Columbia University is perhaps doing more than any one man to divert the funds squandered by the millitarists into educational channels and to lead the mass of the people to see themselves as others see them and to assume full responsibility for the orderly development of their own lives. During vaca- tions some of our students make a practise of giving public lec- tures on hygiene and preventive medicine; but what are one or two among somany? Iam thoroughly in sympathy with Doctor Peter’s public health campaign but I should like to see it on a much larger scale like the world-wide demonstrations of the Inter- national Health-Board. The Chinese people are not devoid of business instinct and I am inclined to think if it were demon- strated to them repeatedly how much may be actually gained by improved sanitation and through an intelligent appreciation of the principles of hygiene, that they would not be unresponsive. Every means of publicity should be utilized and the vernacular press pushed to the limit in a concerted attempt to educate the general masses of the population to a realization and apprecia- tion of the good work which is being done in the medical schools and hospitals throughout China, emphasis being placed upon those under Chinese control. At the same time wealthy merchants and business men should face their duty to their country. It would not be at all a difficult matter to select a group of five or six Chinese in each of the great 40 BE. V. COWDRY cities of Kankow, Shanghai and Canton who could, with but little personal sacrifice, establish and maintain a medical school on an equally efficient and elaborate scale to that founded through the generosity of an American citizen in Peking. The example has been set and I think that we can count on its being followed.’ A list of the medical schools with the names of the anatomists follows. Those marked with * were personally visited. Canton . *Kwangtung Provincial Medical College. 2. *Hackett Medical College for Women. Harriett M. Allyn (part time) S. W. Kwan (part time) 3. *Kung Yee Medical School D. J. Todd (part time) J. A. Hofmann (part time) John Kirk (part time) Wong Tak Kwong (part time) Wong King Yip (part time) Ch’ui Kam Ch’i (part time) ~ . *Kwang Wha Medical School . *Ecole de Medicine Franco-Chinoise de Canton Gilbert Desrallons (part time) P. Tsoi (part time) Liang Yueh Medical College Chee Sek-chong Leung Kin-Cho (part time) Changsha Hunan-Yale Medical School T. C. Lieu A. 8. Crawford (part time) J. W. Williams (part time) P. C. Chu (part time) _ oe o ~ Chengtu 8. West China Union University H. L. Canright (part time) W. R. Morse (part time) 2“Tn connection with the proposed organization of a University in Amoy, for which $4,000,000 has been donated by Mr. Chen Kia-Keng, a wealthy retired merchant in the Straits, it is now reported that another rich Straits merchant, Mr. Wang Yig-Chu, has given a further sum of $3,000,000 for the establishment of a medical college in the University.’ (China Medical Journal, 1920, vol. xxiv, p. 216.) 10. 12. 13. 14. ule 18. 19. 20. ANATOMY IN CHINA 4] Foochow . Union Medical College Jesse Gossard (part time) Hangchow Hangchow Provincial Medical College Li Ding Hangchow Hospital and Medical Training College Tsu Peh Long Dzen Ven Dah (part time) Hongkong *Hongkong University H. T Earle (part time) Kenelm H. Digby (part time) C. C. Wang (part time) Mukden *South Manchuria Railway Medical School K. Shiino K. Kudo T Mikami *Union Medical College R. H. Mole (part time) Nanchang Nanchang Provincial Medical College Paotingfu . *Chihli Provincial Special Medical School Chang Peh Ching Tien Yuen Chin (part time) Peking *Army Medical School C. P. Ch’ang W.S. Kuei (part time) C. Y. Hei (part time) *Government Medical School K. Ikegami Dr. Futamura *North China Union Medical School for Women Ethel Leonard (part time) Li Pau Chen (part time) *Peking Union Medical College of the Rockefeller Foundation EK. V. Cowdry Davidson Black S. R. Detwiler R. 8. Stone Paul H. Stevenson 42 EB. V. COWDRY Shanghai 21. *St. Johns University (Pennsylvania Medical School) I. M. Merrins Dr. Lincoln (part time) Dr. Yin (part time) W. S. New (part time) 22. *L’Aurore University Medical School Dr. Florence R. P. Hernault 23. *Tung Chi Medical College (being a continuation of the former German Medical School) Soochow 24. *Soochow (Kiangsu) Provincial Government Medical College Sah Fou-Zien Tsu Ho Yung Tientsin 25. *Naval Medical School Tsinantu 26. *Shantung Christian University (1918-19) R. T. Shields . L. M. Ingle Wu Djao Hsiang Wang Hwei Wen BUILDINGS AND EQUIPMENT The anatomical laboratories in China vary from a single bare room to costly buildings fitted with every convenience. The” anatomical laboratory of the Peking Union Medical College, here illustrated is certainly the most elaborate. The anatomical lab- oratories of the Japanese Medical School in Mukden are housed in a plain but substantial building and are fully equipped with everything necessary for teaching and research. The University of Hongkong has good reason to be proud of the School of Anatomy erected in a splendid location, high up on the mountain side largely through the generosity of the late Mr. Ng Li Hing, one of the leading merchants of the colony. Mention should also be made of the new anatomical laboratory of L’Aurore University, the austere simplicity of which is quite pleasing. Some of the Chinese institutions are a strange mixture of the old and the new, Occasionally one may see mirrors placed at the top of a flight of ANATOMY IN CHINA 43 stairs, and in other strategic positions, in order to turn back the evil spirits and in this way make the place more healthy. I shall not take space to describe the smaller laboratories, some of which are very unprepossessing, except to say that good work may be done with very meagre equipment if it is gone about in the right way. One becomes very tolerant in China. From modest beginnings great developments may be expected. The mere rudiments of anatomy properly or even.indifferently taught will serve to indicate the fallacy and the danger of native Chinese medicine. Our policy is to encourage and stimulate, not to go away with the feeling that the conditions are hopeless. Both large and small institutious suffer from lack of library facilities. At present there is no library in the whole of China to which one can refer for back numbers of standard European jour- nals. Some are to be found in Peking (where the library ofthe Peking Union Medical College is being rapidly enlarged) one or two in Shanghai and a few more in Hongkong. Tung Chi has a few valuable sets of German journals. Under these condi- tions teaching is hampered and research work is set aside because it is not altogether satisfactory to have to devote time and energy to a problem which may already have been solved by some one else: Dr. Greenman’s policy of the wide distribution of the Wis- tar journals in China is most helpful and constitutes an important step in the right direction. The relatives of the late Mr. Andrew Carnegie could make no more fitting memorial to him than the establishment of a real library in China, free to millions of people. STAFF The twenty-six medical schools of China number only about two dozen teachers who are able to devote all their time to anatomy. These teachers are certainly overworked but their plight is not so bad as those who have to teach a whole variety of subjects and sometimes have to attend to hospital and, more _ rarely, to private practice in addition. Often the instructors are so busy that they have neither the time nor the energy to settle down and do one thing well, with the result that makeshifts and time saving devices are resorted to. Chinese medical schools are 44 E. V. COWDRY inferior to those of Japan in this respect. It is not that those in authority fail to appreciate the gravity of the situation; they are simply unable to remedy it through lack of funds. In several schools, however, one cannot help feeling that some of the money invested in buildings could more profitably have been spent on the staff. The teachers suffer with the students. They leave promising, perhaps remunerative, careers behind them and come out to China young and enthusiastic. They have innumerable demands upon their time and energy, they do really pioneer work in isolated stations, and become, to some extent, ‘Jacks of all trade.’ Middle age finds them often with large families, but without that modern prerequisite—a specialty—so that they are just a little out of the running for positions in the modern and up-to-date medical schools which are bound to spring up. It is essential that anatomists and others shall have a certain amount of leisure time to plan their teaching, to keep up with world progress and to engage in research. Unfortunately it is always easier to secure funds for buildings and equipment, which represent something tangible and permanent, than for the sal- aries of teachers and investigators. With patience, however, the condition in China will slowly improve. TEACHING With foreigners of so many nationalities it is not surprising that the methods of teaching anatomy should be varied. Per- haps the most pernicious system is as follows: The foreign in- structor, who speaks not a word of Chinese, comes in and makes anatomical drawings on the blackboard and labels the parts. A Chinese interpreter then makes his appearance and translates the terms into Chinese. When the students return next day they are required to repeat the drawings from memory. They have no practice in dissecting, even on animals, and accordingly have to learn how to use their instruments upon the living subject, sometimes with disastrous results. One of my questionnaires was answered as follows: ‘‘We don’t teach histology, embryology, comparative anatomy, as our scope is to form practitioners only. Besides, the intel- ANATOMY IN CHINA 45 lectual standard and scientific previous education of our scholars are not high enough to allow us to emphasize pure science.”’ The greatest stumbling block in the teaching of anatomy, next to inadequacy of staff, is the difficulty of obtaining human mate- rial for dissection. To the best of my knowledge only the Jap- anese Medical School at Mukden and the University of Hong- kong have a sufficient and regular supply of bodies on which they ean rely. Only twelve of the twenty-six medical schools offer regular courses in human dissection. In Peking we have only been able to secure four bodies in the last year and a half. When the first entered the building all our servants left us immediately and we had some difficulty in replacing them. The police and the authorities generally are not sympathetic, and there seems to be but little hope of obtaining sufficient material in Peking for sometime to come. In the provinces some of the schools obtain material from executions but this source is sporadic and unsatis- factory. It is interesting that in Japan, where the worship of ancestors is also prevalent, bodies may be obtained more easily than perhaps anywhere else in the world (Cowdry ’20, p. 72). The regulations regarding dissection of the Chinese Govern- ment are as follows, quoting the translation given in the China Medical Journal: Order of the Board of Interior No. 51, November 22, 1918: Article I. A physician, in case of death from disease, may dissect the body and inspect the diseased part to determine (examine) the origin of the disease, but he must first obtain the consent of the rela- tives of the dead person and clearly inform the local magistrate before proceeding to dissection. Article II. The police and inspectors, in case of mysterious death, the cause and origin of which cannot be accurately ascertained without dissection, may appoint a physician to dissect said corpse. Article III. The bodies of all those meeting death by punishment or dying in prison from disease, without relatives and friends to claim their bodies, may be given by the local magistrate to a physician for dissection, to be used for the purpose of experimentation in medical science, but after dissection the body must be sewed up and buried. Article IV. If any are willing for the benefit of science to offer their bodies for dissection and leave word to that effect before death, they may do so, but the whole body must be sewed up and returned to his or her family after dissection. 46 E. V. COWDRY Article V. These regulations are in force from the day of their proclamation. Supplementary order of the Board of Interior, No. 85, April 22, 1914. Article 1. All medical colleges and hospitals, which are proved to be in good condition by the local authorities and recognized before- hand by the Board of Education or established by the public, shall be allowed to perform dissections. Article 2. According to Acts No. 1 and 4 of the General Laws this may be enforced and the medical men allowed to perform post- mortems as soon as the consent of the family is obtained. (During summer this may be done immediately after reporting to the local authorities.) Article 3. When the colleges and hospitals mentioned in Art. 1 of By-laws apply for any dead body from the local authorities the follow- ing rules must be observed :-— 7. Proper letters with official seals are needed on both sides—local authorities and the college—when dealing with any deceased criminal or deceased prisoner. Any private medical college recognized by the Board of Education may also apply in similar manner. ii. Special certificates shall be made by the judicial authorities of the local government, and the same shall be given at the time when dead bodies are issued to the medical colleges. After examination the certificates shall be kept in the college until the end of the month when they shall be returned to the local authorities so as to enable them to ~ preserve records. There shall be no need to send these to the prisons. wii. The name, age, district, and number of the dead person shall be noted in the certificate, which shall be properly dated with official seals by the local government before the same is sent. The college receiving the corpse shall keep a copy of the name, age, date, ete., so as to facilitate examination when required. Article 4. A certificate of death by a qualified medical man shall first be sent to the local authorities before a post-mortem examination is allowed on certain persons, who have not died in a hospital as men- tioned in Art. 4 of General Laws. After examination a report shall be submitted to the local authorities for reference. Article 5. With the exception of Arts. 1 and 4 of General Laws any or many parts of a dead body dissected may be retained, if such are necessary for medical demonstration. This may be done according to Art. 3 of General Laws. Article 6. When any or many parts have been removed from a dead body for medical demonstrations, the rest of the corpse shall, if possible, be sewed up according to Arts. 3 and 4 of General Laws. (Dead bodies mentioned in Art. 3 of General Laws which are supplied to medical colleges shall be treated in the same way.) Article 7. A dissected body after being sewed up shall be returned to the family if possible. If unclaimed it shall be buried by the college which has dissected the body. After the funeral, a sign shall be shown ANATOMY IN CHINA 47 on the tomb where the deceased has been buried. (Any deceased per- son having no family as mentioned in Art. 3 of General Laws may be taken to a crematorium by the medical college and cremated if neces- sary. After burning, the ashes of the deceased shall be gathered and buried, and proper signs shown on the tomb. This shall be duly reported to the local authorities.) ~ Article 8. All medical colleges shall report yearly the number of dead bodies dissected, to the police court if at Peking, and to the local authorities at other places, in order to facilitate reporting to the Board of Interior for the preservation of the records. Article 9. These By-laws may be revised at any time with a view to improvement. Article 10. These By-laws shall be enforced on date of promulgation. The chief difficulty is that these regulations are interpreted to mean that the written consent of the individual before death must be supplemented by the sanction of the relative, which it is almost impossible to obtain. Owing to the pressure of other duties, the teachers are often ungble to properly adapt their methods of teaching to the lack of human material. They soon come to rely upon the use of anatomical models made in Europe or Japan and give up their efforts to obtain bodies for dissection; for it takes a lot of time and energy to cultivate the authorities, to drink endless cups of tea, to make petitions for favorable legislation and arrangements for executions. Yet it is possible, with a little care, to give the students an idea of the science of anatomy without the aid of human dissection. It is usually quite a simple matter to obtain a skeleton from abroad or even in China. For instance, the stu- dents at Paotingfu have, through their own initiative, amassed quite an interesting and useful collection of bones from the graves in the vicinity. Living models should be used extensively. The students should be obliged to make a careful and complete dis- section of some mammal comparing the structure carefully with that of man. In the south of China advantage may be taken of the monkeys which are sold as pets, for from two to five dollars a piece. Lack of time and insufficient laboratory equipment are re- sponsible, in some cases, for a rather low standard of work in histology, embryology and neurology. 48 E. V. COWDRY While the teaching in the better schools is worthy of the highest praise, there is a general tendency, which I have already noted in the case of the Japanese medical schools, to give too many lectures and too little laboratory work. It is true that the cost of laboratory furnishings may be a certain deterrent; but, on the other hand there is the time factor. It is more wearing on the teacher to give one hundred lectures than to teach in the labo- ratory for the same length of time. The proportion of lectures to laboratory work in some of the principal colleges is given in table 1. TABLE 1 Proportion of lectures to laboratory work in anatomy* COLLEGE LECTURES LABORATORY per cent per cent Ariny’ Medical Schools ..c2 cy. +s sas ba wes ee cate etclen cen 83.0 17.0 Chekiang Provincial Medical College................. 86.6 13.4 Chihli Provincial Medical College.................... 91.3 8.7 Ecole de Medicine Franco-Chinoise.................+. 100.0 0. Hackett Medical College... 2 0:........0cccccceusceece 35.8 54.2 Hangchow Hospital and Medical Training College... . 80.0 20.0 Hunan Yale Medical College................00.0eese08 32.7 67.3 Japanese Medical School, Mukden.................... 50.0 50.0 Kiangsu Provincial Medical College.................. 71.4 28.6 Kung: Yoo Nedical College: ooo... . 5 tulcei ders onlemes 36.9 63.1 Liang-Yueh Medical College.................02eee+00: 80.0 20.0 Peking Governmental Medical College................ 70.4 29.6 Peking Union Medical College..................ee.00% 10.0 90.0 West China Union University................ceeeee0s 40.5 59.5 This high percentage of lectures is very bad for the students. It means that most of their information comes to them second hand, predigested in the mind of the lecturer, and that they are, to a large extent, robbed of the incentive and privilege of making observations for themselves and of learning how to make logical deductions therefrom. This method of training does not teach the student self reliance, which is particularly necessary in China, where, after graduation, he is often placed entirely on his own resources without sympathetic and stimulating help from those around him. ‘Unfortunately information has not yet been received’ from St. John’s University. ANATOMY IN CHINA 49 In some colleges the time devoted to anatomy is altogether too long. I learn for example, from the Kung Yee Medical College, in answer to my questionnaire, that the students suffer 1178 hours of instruction in anatomy. Long hours with lack of time to think and of opportunity to pursue work along special lines, chosen by the students themselves, is deadening. It usually fails to create in the student a thirst for knowledge and a desire to help himself. There is one more consideration in the training of the student which should, in my opinion, receive attention in view of the fact that it is the purpose of the medical schools to turn out men of strong character, not merely physicians skilled in their pro- fessions. Reading through the printed announcements of the various colleges we meet with catagorical prohibitions relating to the conduct of the students. A merely negative attitude of this kind does not itself tend to strengthen character. When all restraint is removed and the student leaves the college a reaction is in danger of setting in. It is surely through education, teach- ing that what is right is also expedient, that the best results are to be obtained. The standard of instruction has unquestionably been raised by the action of the Council on Medical Education (1915) in urging the various medical schools to meet the following requirements necessary for admission to ‘Grade A’ 1. Course of Instruction. That the course of instruction shall extend over a period of five years of, at least, 32 weeks each. That the text books used and the instruction given shall be equivalent to that in European and American schools. That human dissection, and complete courses in laboratory work, shall be included in the curriculum. 2. Entrance Requirements. That the standard of admission shall be graduation from a Middle School as defined by the Edu- cational Association of China, and, in addition, at least one year of preliminary work including laboratory courses in physics, chemistry and biology; this preliminary or ‘‘pre-medical” year being arranged to supplement the preparatory instruction already given in Middle Schools. 50 E. V. COWDRY 3. Hospital Year. That before receiving a medical degree, students who have completed the five years of regular instrue- tion, shall spend one year as interne in an approved hospital, or in some other line of special medical work, at the conclusion of which the applicant for a degree shall present a thesis acceptable to the faculty of the medical school. 4. Degrees. That only students who have met the entrance requirements, have completed the regular course of instruction in an approved school, and at the termination of the hospital year have presented an acceptable thesis shall be entitled to receive a medical degree. 5. Staff. That the minimum staff shall be ten men on the field giving full teaching time. To provide for furloughs, lan- guage study, ete., this requirement means a staff of at least fif- teen fully qualified teachers either foreign or Chinese. 6. Equipment. The school must be adequately equipped with modern appliances for instruction, properly equipped laboratories in Chemistry, Pathology, Bacteriology, Anatomy, and Clinical Microscopy, and must be maintained on an efficient basis. The scientific instruments and apparatus shall be sufficient to permit students to do individual work. ?. Hospital Facilities In connection with each medical school and under control of the faculty, there shall be one or more hos- pitals suitable for teaching purposes, each hospital to have at least 100 beds. One or more daily dispensaries should be con- nected with the college hospital. 8. Curriculum. The schools approved by the C. M. M. A. shall meet the curriculum requirements which the Council on Medical Education will prepare in detail upon the lines already suggested. While travelling from college to college one is impressed with the relatively small attendance. Very few of the colleges are filled to capacity. This is to be attributed to the fact that the science of medicine does not appear to be very attractive to Chi- nese students, rather than to the lack of premedical training which may easily be secured in Peking, Shanghai, Hongkong and the larger cities. It is difficult to ascertain the maximum number ANATOMY IN CHINA 51 of students which may enter the medical schools of China each year, because in the poorer schools, where but little attention is given to laboratory work, almost any number may attend the lectures. The Chinese Government Schools are certainly much better attended than the missionary establishments, perhaps because their entrance requirements are less exacting. ‘Table 2 will show how meagre is the supply of doctors which is being trained to supply the needs of 400 million people. The entering classes of 16 colleges combined only contain 355 students. Con- trast this with the conditions following the war in the United States and Canada. The University of Toronto, for. instance, has an entering class in the medical school of 416 students to supply the needs of a country with a population of about 8 millions, already quite well stocked with doctors. During the last few years the following medical schools have been closed, partly through a desire to concentrate activities and thus increase the standard of work: Harvard Medical School, Shanghai. Women’s Medical School, Soochow. University of Nanking Medical School, Nanking. Union Medical College, Hankow. German Medical School, Tsingtau. Provincial Medical School, Wuchang (?). The following resolution of the Council on Medical Education (1920) seems to forecast the closure of other schools through lack of adequate support: That in view of the difficulties hitherto experienced in securing ade- quate staff and support for the medical schools at Changsha, Chengtu, Mukden and Foochow, the Association would commend to the incom- ing Council the careful consideration of the following question, in con- paehon with the missions interested in the development of those schools: a. Whether steps can be taken to meet the urgent need of a broad- ened basis of support for the Medical School at Changsha, by the pro- visian of an adequate endowment, or by the full co-operation of missions working in that area, in view of the fact that should this not be obtained, the continued existence of the school will prove impracticable. b. Whether the Missions at work in Southwest China can set aside a sufficiently large staff of efficient teachers to enable the West China THE ANATOMICAL RECORD, VOL. 20, No. 1 52 E. V. COWDRY Union University Medical Department to approximate to the C. M. M. A. minimum requirements. c. Whether some measure of co-operation between the Union Med- ical College, Mukden, and the School of Medicine, Tsinan, could not be satisfactorily arranged. d. Seeing that the Fukien Christian University is not intending to develop a medical department, as the Council is informed, should not the authorities of the Fukien Medical College be urged to reconsider the continuance of that school? TABLE 2 Actual attendance and teaching capacity ACTUAL MAXIMUM COLLEGE eahidenpe ao NUMBER Army NediCn iS QNOUL Ze n.0 sce ids oss oo an Cera ins eels 51 85 Chihli Provincial Medical College. ................... 42 45 Beole de Medicine Franco-Chinoise de Canton........ 25 Hackett: Medical: College: oo oii «cit as cots sohertraen eels 14 Hangchow Hospital and Medical Training College.... 21 50 Hangchow Provincial Medical School................- 30 80 Hunan Yale College of Medicine.................... er 7 Japanese Medical School, Mukden.................... 57 60 Kung, Yeo Medical College... , * ; ( ‘Sra? I Fialie =P) y toh i ai! Ree i alte. 4 Poe a) gal? sci8 yt na’ 7 J reir) Dy egy y ¥ af a ah eee. ‘ee ° OT a eae “o!) CONie aia. LS mais Vee | =] - —_ a = 5 o> Wie >. Vee inetlts: Gi < Ay ip a Gib 2c pra i 1 ees ee » or ) Cary ey Mish hile oop" + ae ite Wiha ln antl ye ey del i Me 4) iw « iebtan ree a> We Te beicioe pail ca .. ie Resumen por el autor, Eugene i Settles, University of Missouri. Los efectos de una dieta grasa abundante sobre el crecimiento del tejido linfoide. Dos gatos jovenes procedentes de la misma erfa fueron alimen- tados durante cuatro meses y medio, uno con leche que contenia 6 por-ciento de grasa, el otro con la misma cantidad de leche con 3 y medio por ciento de grasa, suplementada en el caso del primero por carne grasa y en el tiltimo por carne magra. Despues del primer mes ambos presentaban excelente salud. El gato que recibfa alimento rico en grasa presentaba un exceso en el peso del cuerpo y 6rganos, como indican las siguientes cifras: Peso total (despues de deducir el exceso de grasa), 30%; timo, 84.8%; glandula linfitica mesentérica, 52.7%; bazo, 23.8%; higado, 93.7%; pancreas, 80.6% ; tibia izquierda, 44.1%; fémur izquierdo, 34.6%; coraz6n, 21.1% y rifiones, 27 por ciento. De estas cifras se deduce que el timo y la glindula linfaitica mesentérica, junto can el higado y pdncreas, presentan un exceso de peso relativamente mucho mayor que el exceso del total. El estudio microscépico demostré un exceso aun mayor en la cantidad de tejido linfoide a lo largo del canal alimenticio (ténsilas palatinas y farfngeas, placas de Peyer y foliculos soli- tarios). Las placas de Peyer eran tres veces mas grandes que lo normal y se hallaron numerosos folfculos solitarios y acumula- ciones linfoides mas pequefas en el gato alimentado con la dieta mas rica en grasa, mientras que en el otro no se pudo hallar nin- gun folfculo solitario. De estos datos el autor concluye que el tejido linfoide responde con marcadas diferencias en su cantidad a las diferencias en la dieta, consistentes en diferencias en el . contenido de grasa y valoren calorias. Estos dos factores no han podido separarse atin. Translation by José F. Nonidez Cornell Medical College, New York AUTHOR’S ABSTRACT OF THIS PAPER ISSUED BY THE BIBLIOGRAPHIC SERVICE, NOVEMBER 1 THE EFFECT OF HIGH FAT DIET UPON THE GROWTH OF LYMPHOID TISSUE EUGENE L. SETTLES Anatomical Laboratory of the University of Missouri SIXTEEN FIGURES (3 PLATES) In spite of the universal interest in and the innumerable studies which have been made upon lymphoid tissue, very little has been learned regarding the factors which regulate its normal growth. It is known that lymphoid tissue is relatively much larger in amount during infancy and childhood and that it diminishes during adult life. It is also known that enlargement of lym- phoid tissue may result from the effects of acute or chronic inflam- mation. However, the great variations in the lymphoid tissue, which are well known to occur, especially during childhood, form - an unsolved problem. Since the most important differences in the factors to which young animals are subjected are those associated with differ- ences in diet, it seemed worth while to investigate the effect of varying diets on the amount of lymphoid tissue. The food ele- ment which seemed most likely to have a specific effect was thought to be fat, and for the following reasons. Schiifer (’85, ’12), who has made numerous studies on the rela- tion between leucocytes and fat absorption, concludes from his own work and that of others that leucocytes, some varieties of which are formed in lymphoid organs, are known to take up fat in the villi and transport it to the lacteals. Kischensky ('02), in studying the intestinal epithelium of young kittens during fat absorption, found leucocytes contain- ing fat. From his description we may conclude that ‘these small round cells with large nuclei” are lymphocytes. He also found fat droplets in the macrophages of the lymph glands four to six hours after a meal. 61 62 EUGENE L. SETTLES E. R. and E. L. Clark (’17) observed that leucocytes are at- tracted to and actively ingest injected fat in the transparent tails of living amphibian larvae. Again, lymphocytes contain lipo- lytic ferment, while polymorphonuclears contain proteolytic fer- ment (Fiessinger and Marie, ’09). Czerny (’07) says that, with hypertrophy of fat in children, he finds enlargement of the tonsils, thymus, adenoids, and of the deep and superficial lymph glands, and that with regulation of diet in adiposity, he finds a diminution in size of lymphatic organs. Hutinel (according to Steehman, ’10) says that in acute intes- tinal inflammation after healing of theintestinal processes them- selves there is a persistent emaciation of the child due to the dis- turbance of function of the mesenteric lymph glands. He also studied mesenteric lymph glands of dogs in different stages of digestion, and concluded that during digestion fat is emulsified in the mesenteric lymph glands and further worked over, and that here there must be a real chemical change. He says that the colorless content found in lymph vessels is soap. He also says that all the lymph glands play a similar réle in inanition. Poulain (’02) states that lymph glands play a double réle in digestion, in that there occurs in lymph glands both splitting and synthesis of fat. He also says that during infection there is a lessened lipase activity of lymph glands and concludes that this may be the explanation of the general disturbance of nutrition which is found in intestinal infection. Steehman (’10) investigated the question of relationship of lymph glands to fat digestion, and his conclusion is that the lymph glands are definitely concerned in the digestion of fat, and he states that they are assimilative organs for the fat derived from the tissues. Bartel and Stein (06) quote Paltauf, who holds that the en- largement of the thymus in status lymphaticus is not the cause of death, but merely a symptom of the general disturbance of metabolism further characterized by enlargement of the tonsils, lymph glands, and other lymphoid organs. He also describes fatty livers in many of these cases. EFFECT OF HIGH FAT DIET ON LYMPHOID TISSUE 63 According to Kanthack and Hardy (’94), a meal causes a con- siderable rise in the number of lymphocytes in the blood. In rabbits, after a meal, they may form from 70 to 80 per cent of leucocytes, while in man two hours after a full meal they form about 30 per cent of the white blood-cells. These authors con- clude that active digestion produces lymphocytosis, while starva- tion decreases the number of lymphocytes. Thus, through the literature runs the strain of evidence that the lymphoid tissue plays an important part in the metabolism of fat. It is well known that increase in the specific functions of tis- sues results in an increase in size. Hence, if lymphoid cells are concerned with absorption, transportation, and possibly with digestion of fat, one might expect the organs producing them to increase in size with an increase in the amount of fat handled by them. As noted in the review of literature, the immediate effect of fat feeding has been investigated, and it has been found that the number of lymphocytes in the blood stream increases markedly during digestion, but shows a decided decrease in number during inanition. No definite reference, however, was found in the lit- erature to any studies on the effect of a long-continued high fat diet on the size of lymphoid organs. It was therefore decided to plan experiments to test this question. In addition to the general physiological and anatomical inter- est of this question, there are possible clinical applications of great importanee. If lymphoid tissue is regulated to any con- siderable extent by the amount of fat given in the food, it follows that some of the enlargement of tonsils and adenoids in children may be due to a too high fat diet, particularly in those predis- posed to this trouble by heredity. _The experiments reported here were begun with the idea of discovering the effect of an abnormal increase or decrease in the amount of fat in the diet upon the growth of lymphoid tissue. Milk was selected as the basis of the diet because of the ease of handling its fat content as well as for its general nutritional qual- ities. Kittens were chosen as suitable animals for the experi- 64 EUGENE L. SETTLES ment because of the possibility of feeding them at regular inter- vals and of controlling accurately the amount of food consumed at each meal. A litter of four kittens was obtained for the exper- iment. They were healthy animals, about three weeks old, and had not yet been weaned. It was realized from the start that, if dependable results were to be secured, the animals would have to be attended to with greatest care, particularly as regards cleanliness of food, dishes, and cages, regularity of feeding, and mental condition. On account of the uncertainty of delegating such matters to a chang- ing janitor force, it was decided from the start to feed and care for the animals personally. This was carried out from the begin- ning to the end of the experiment, except for short intervals when dependable substitutes were secured. ‘The milk used was secured on alternate days from a reliable dairy and kept in clean bottles. During the warm weather the milk was kept on ice. The dishes were washed in hot water after each feeding. The floor of the cages consisted of wooden slats, the sides of fine- meshed wire. Water and a pan of sand were kept in each cage continuously, the sand being changed two or three times a week and the cages kept clean. Particular care was taken to keep the ~ kittens free from all infections, parasites, or uncleanly conditions because of the possible effect of such agents upon lymph glands. The kittens were fed the full amount of milk planned for them every day. At first they were fed three times a day, later twice a day, with an occasional day on which the total day’s feeding — was given at one time. The four kittens were kept in separate cages, with ample room for moving about. Throughout the entire experiment they were turned out of their cages frequently and allowed to play and exercise for an hour or more. They were treated kindly; in fact, they grew to be real pets. Since no data were available as to the proper caloric require- ment of young kittens, it was first necessary to determine the normal amount of milk consumed daily. A four-day test showed that the kittens consumed approximately 94 ce. of 3} per cent milk per 510 gram body weight or about 100 calories per kilo of body weight. EFFECT OF HIGH FAT DIET ON LYMPHOID TISSUE 65 It was decided to feed the cats milk varying in fat content, as follows: no. 1, low fat, low calorie; no. 2, normal fat, normal calorie; no. 3, high fat, high calorie; no. 4, high fat, normal cal- orie. Based on the rough estimate mentioned above of 100 cal- ories per kilo, the normal number of calories, and using 33 per cent fat as normal, the four cats were started on the diet shown in chart 1. The calorie contents, not shown in the chart, were: no. 1, 37.08 cal.; no. 2, 58 cal.; no. 3, 78.83 cal.; no. 4, 58 cal. The weights of the cats were, respectively, 510, 510, 538, and 510 grams. 17 78 19 20 This general plan was followed with increase in quantity once, until the death of cats no. 1 and no. 3. Thereafter, cat no. 4 was shifted to a high calorie diet, that is, it was given a daily amount of 6 per cent milk equal to the amount of 33 per cent milk given to cat no. 2. This was done in order to have a decided difference in the amount of fat given to the surviving eats. The data concerning weight changes, amounts of milk given, with dates at which changes in amounts were made, are shown so fully in chart 1, that it is unnecessary to repeat them in detail. However, certain supplementary comments should be made. THE ANATOMICAL RECORD, VOL. 20, No. 1 66 EUGENE L. SETTLES On account of the difficulty of keeping the cats healthy on a pure milk diet, it was decided at the end of a week to give each cat a small amount of meat in order to keep them in good condi- tion. Cat no. 2 received lean meat exclusively, while cat no. 4 was given meat containing small amounts of fat. The feeding of meat was continued throughout the remainder of the experiment, at two- or three-day intervals. This has been omitted from the chart. Changes in quantity were made whenever a stationary weight or increased greediness of the cats made it advisable. A glance at the chart shows that none of the cats responded well to the change incident to weaning and confinement in sepa- rate cages. Instead of the rapid increase in weight which all animals of this age should show, there was a three-weeks period during which the weight remained stationary, as in cat no. 2, or declined, as in cats no. 1, no. 3, and no. 4. At the end of this period cats 1 and 3, which had been respectively on the low and high calorie diet, died, while cat no. 4 was in a very weakened condition. Although cat no. 2 appeared to be healthier than cat no. 4, still it maintained practically the same weight as at the start. It is probable that the death of cats 1 and 3 and the poor con- dition of cats 2 and 4 toward the second of the third week were due to the change from mother’s to cow’s milk, accentuated in cats 1 and 3 by the markedly abnormal fat percentages. After this, however, the condition of both cats no. 2 and no. 4 improved and continued excellent throughout the remainder of the experiment. From the third to the seventh week cat no. 2 increased slowly in weight. From the seventh to the twelfth week its weight remained practically stationary, even though the quantity of milk was increased at two different times. From the twelfth week to the end of the experiment its weight increased steadily, though slowly. After the end of the third week when cat no. 4 almost died, it apparently adjusted itself to the high fat diet and began to gain weight, until, at the eighth week, its weight exceeded that of cat no. 2. From this time on until the end of the experiment the rate of gain of cat no. 4 was much more rapid than of cat no. 2. EFFECT OF HIGH FAT DIET ON LYMPHOID TISSUE 67 During the last two weeks of the experiment, an-attempt was made to increase still further the amount of fat consumed by cat no. 4, consequently 9 per cent milk was given during this period. However, during the first few days following this final change in diet, the cat did not drink the full quantity of milk. During the last week it accustomed itself to this extremely high fat percentage and at the time when the animals were killed it was consuming the entire amount of milk offered. Cat no. 4 was killed on February 11th, nineteen weeks and three days after the beginning of the experiment. Cat no. 2 was killed two days later, at the same time of day as no. 4 and at exactly the same interval of time after the last feeding. The autopsies will be given later. The history of the experiment, as represented graphically in the chart, shows that the original experiment of feeding four kittens of the same litter had be to modified owing to the death of two of the cats at a period before any of the four had become adjusted to cow’s milk and confinement. Cat no. 2 received the same diet throughout, as regards fat percentage, and the amount of diet was determined by the natural appetite of the animal. While its growth was much slower than normal so that the total weight and size of organs cannot be considered normal, neverthe- less it serves as a satisfactory control as regards the effect of dif- ferences in fat content of the diet. Cat no. 4, starting out with a diet of 6 per cent milk containing the same number of calories as the control animal, after the death of cat no. 3, was given the same quantity of 6 per cent milk as that of the 33 per cent milk fed to cat no. 2, hence it received a greater number of calories. During the latter half of the experiment this cat received some fat meat while cat no. 2 received nothing but lean meat. During the last few days of life, cat no. 4 was consuming the amount of 9 per cent milk equivalent to the quantity of 34 per cent milk taken by the control. Hence cat no. 4 was fed a high fat diet throughout the experiment, and after the fifth week it received a high calorie as well as a high fat diet. The cats, as has been stated, were kept clean and free from parasites throughout the experiment, with the exception of a 68 EUGENE L. SETTLES small number of fleas which appeared at times and were treated with insect powder. The general condition of both was excellent during the last fifteen weeks. AUTOPSIES Cats no. 1 and no. 3 Owing to the fact that cats nos. 1 and 3 had failed to adapt themselves to cow’s milk and had been in an increasingly weak- ened condition for several days before they died, it was thought that little would be gained from extensive study of the lymphoid organs. Careful autopsies showed nothing markedly abnormal in the thoracic and abdominal organs. The large mesenteric lymph gland from each cat was weighed and examined micro- scopically. The weight of the gland from cat no. 3, 1.470 grams, exceeded that from cat no. 1, 1.423 grams, by 0.047 gram. Mi- croscopic examination, however, showed a definitely larger num- ber of lymphoid cells making up the cortex and medullary cords and filling the sinuses in cat no. 3 as compared with cat no. 1. Cats no. 2 and no. 4 As previously mentioned, both these cats were in perfect health at the end of the experiment; their coats of fur were smooth and silky and they were active and playful. Cat no. 4, which had been fed the high fat diet, was larger and heavier and con- spicuously fatter than cat no. 2, which had received a normal percentage of fat. The two cats were killed at exactly the same hour of the day and at the same length of time after the last feeding. Autopsy of cat no. 4 (male). Cat was killed with chloroform February 11th at 9:50 a.m. The last feeding was given at 2:30 p.M., February 10th. There is a layer of subcutaneous fat over the abdomen, about one-quarter of an inch thick. Much fat is present in the omentum. ‘The peritoneal, pleural, and pericar- dial surfaces are smooth and shiny, with no increase in fluids in these cavities. The lacteals are well injected with fat. The EFFECT OF HIGH FAT DIET ON LYMPHOID TISSUE 69 chief mesenteric lymph gland is homogeneous in appearance and seems large and swollen. It weighs 3.040 grams. The other small, scattered mesenteric lymph glands were not noticeably increased in number. The stomach and intestines show nothing abnormal from the outside. On opening, the stomach is found to contain a considerable amount of partly digested material and the small intestine much yellowish semisolid material. No worms or other parasites were visible to the naked eye in stomach or intestine. ‘The mucous membranes showed no especial redden- ing or other abnormality. In the lower part of the ileum, the Peyer’s patches (folliculi agminati) stand out with exceptional clearness. They form mottled raised areas projecting into the lumen of the bowel clearly marked out from the surrounding mucosa. The largest patch is the one in the terminal ileum, just above the ileocecal valve, which measures 3 cm. inlength. In the 12 em. of intestine anterior to this there are four round patches, each about 1 em. in diameter, all conspicuously raised over the surrounding surface. The pancreas is large and normal in appearance, weighing 9.055 grams. The spleen is dark red with numerous white spots, and has rounded edges. It weighs 3.060 grams. ‘The liver is very large with rounded edges, and has a yellowish color. It weighs 118 grams. The right and left kidneys are dark red in color, showing nothing abnormal. Their weights are 6.5 and 6.7 grams, respectively. The lungs are air containing and normal, save for one small atelectatic area in the upper right lobe. The heart is surrounded by a considerable amount of fat. It shows nothing abnormal. Its weight is 7.9 grams. One each of the right bronchial and right inferior cervical lymph glands were exam- ined and preserved. They show nothing unusual macroscopi- cally. The thymus is homogeneous in appearance and seems unusually large. It weighs 5.495 grams. The right and left tonsils are covered with hemorrhagic spots. In order to preserve them without injury for histological study, some of the surrounding tissue was dissected out with them, therefore it was not possible to estimate their weight accurately. The pharyngeal tonsil which is located at the top and posterior wall of the pharynx, is 70 EUGENE L. SETTLES easily seen as a definitely raised area containing many raised whitish translucent spots. The left femur was preserved. It weighs 6.557 grams, while its greatest length is 7.8 mm. The left tibia was also preserved. Its weight is 5.200 grams and the greatest length is 83 mm. Most of the subcutaneous fat was dis- sected out. It weighs 109.4 grams. Either all or parts of the various organs were preserved in Zenker’s fluid for microscopie study. Autopsy of cat no. 2 (male). Cat was killed with chloroform, February 13th at 9:20 a.m. The last feeding was given at 2:30 p.M., February 12th. There is little fat present over the abdo- men. ‘The omentum likewise contains little fat. There is no increase in the fluid in the pleural, pericardial, or peritoneal cavi- ties. Linings of all these cavities are smooth and shiny. The lymphatics are filled with chyle. The chief mesenteric lymph gland is homogenous in appearance. Its weight is 1.990 grams. The stomach and intestine show nothing abnormal externally. On opening, the stomach is found to contain a small amount of nearly digested food and the small intestine contains very little except some brown mucus. No worms or parasites were visible to the naked eyes in the stomach or intestine. The mucous mem- branes are apparently normal. On opening the lower end of the ileum, it is found to be practically empty. A long Peyer’s patch isfound here. It is scarcely raised above the general epithelial surface and its extent is difficult to determine. The remainder of the small intestine was searched carefully for other Peyer’s patches, but none could be seen in the gross specimen. The presence of the brown mucus here possibly prevented us from discovering the smaller patches at the time; however, the entire small intestine was preserved for further examination. The pancreas shows nothing abnormal. It weighs 5.540 grams. The spleen has sharp, definite edges and its surface is mottled with small round nodules. It weighs 2.470 grams. The liver is nor- mal apparently; it is dark red in color and has sharp edges. Its weight is 60.9 grams. The right and left kidneys are normal in appearance, weighing 5.1 and 5.3 grams, respectively. The right lung shows a small atelectatic area, otherwise both lungs are EFFECT OF HIGH FAT DIET ON LYMPHOID TISSUE ral normal. The heart is normal, weighing 6.5 grams. The thymus is very pale. It weighs 2.973 grams. The largest right inferior cervical lymph gland shows nothing abnormal macroscopically. It is very pale in color. At the roof of the pharynx in the place where the pharyngeal tonsil was easily seen in cat no. 4, only a faint mottling can be seen. On dissecting this tissue loose from the bone and examining it carefully, definite small nodules may be seen. ‘The left femur was preserved. It weighed 4.870 grams and its greatest length was 67.5mm. ‘The left tibia was also pre- served. Its weight is 3.607 grams and its greatest length 73 mm. DISCUSSION OF AUTOPSY FINDINGS OF CATS NO. 2 AND NO. 4 The postmortem examination confirmed the observations of the living animals that the two animals were entirely free from disease. It is noteworthy that no parasites were found. The difference in the weight of these two animals at the time of death has already been referred to. It was obvious merely from the superficial inspection at the time of autopsy that the subcutaneous fat, the fat in the omentum and around the heart was noticeably greater in the cat which had received the high fat diet. Moreover, the macroscopic appearance of the liver, with its rounded edges and yellow color, made it appear highly proba- ble that the difference in the weight of this organ in the two cats was due to an extra fat content in cat no. 4. (This was later confirmed by histological findings.) Aside from these differences in stored fat, the most noticeable difference in the two cats was found in the lymphoid tissue. Even without the comparison of the weights of the different lymphoid organs, the greater size of those in the fatter cat was very apparent. This was epecially noticeable in the case of the Peyer’s patches. In the cat fed on high fat diet, the Peyer’s patches were large, discrete, conspicu- ous, and prominently raised above the intestinal wall, while those of the cat fed on normal fat percentages were scarcely raised above the epithelial surface and so inconspicuous as to make their detection very difficult from macroscopic examina- tion. The same contrast, in somewhat less degree, was notice- able in the case of the pharyngeal tonsils. The lymphoid tissue 72 EUGENE L. SETTLES in the pharynx of cat no. 4 was fairly thick and well raised above the surface, while in this same region in cat no. 2 the lymphoid tissue was represented merely by a faint mottling of the roof of the pharynx. The comparison of a number of the organs of the two cats is best brought out by a chart showing the weights. These weights were all obtained in the fresh state. Chart 2 gives the weights of the larger lymphoid organs (such as mesenteric lymph glands, thymus, spleen, etc.) of the two cats and also the weight of other organs (such as the heart, kidney, liver, etc.) for the sake of comparison. The smaller lymphoid organs, such as the Peyer’s patches, the palatine tonsils, cervical lymph glands, and pharyngeal tonsils, could not be accurately weighed on account of the necessity of leaving some of the sur- rounding tissue attached to them, hence the comparison of these was based upon microscopic study. In chart 2, the weights of the two cats, and the absolute and relative weights of their various organs are first given. The excess body weight of cat no. 4 over cat no. 2 is next shown, together with the excess weight of its various organs. For several reasons the body weight of cat no. 4 should be corrected, in order to obtain a fair comparison of the various organs. It has been mentioned that 109.5 grams of subeuta- neous fat was found in cat no. 4, while cat no. 2 had very little subcutaneous fat. Again, the liver of cat no. 4 proved to con- tain an enormous amount of stored up fat. Beside these two fac- tors, the gastro-intestinal contents were much greater in cat no. 4 than in cat no. 2. Now it would seem that the organs which would give the best relative comparison between animals such as these two cats at the end of the experiment would be the heart, kidneys, and perhaps the skeleton. On obtaining the average of the percentages by which cat no. 4 exceeds cat no. 2 with re- spect to heart, kidneys, tibia, and femur, the result arrived at is approximately 30 per cent. This same figure is obtained approx- imately if the excess subeutaneous fat (109.5 grams) plus a por- tion of the liver weight (37.5 grams), which accounts for only part of the stored-up fat, be subtracted from the gross body weight PEP 0 AGNGIM LAAT Soe 6 VLG T1é iat PT Ir'0 0s°0 ¢'9 6°L SIF'0 |€€S°0 (0) 0g'°9 saxers | aavan *pasn SI f ‘OU 4UO JO 4YFIOM poyoo1I09 ayy Sandy osoyy IO, , Mizar | Uda oe Oeste Ml Pytddor|| (ite | ea ae sv -gysteam Apo payor -109 Jo uaa ted sso0xa pue suevdi0 jo quad sad Ssoox9 UddBA oq sdUAIOAIC, 9° PE LW 9°08 | 2°86 LOs 8°&% 88 | Ee ce ha pe 1) OM) FBO TesO F ‘Ou wo ‘ssooxe yuad Jag 289°T 869° |SIS"F T2g |OS0'T |c6S°0 j\eec°s TCOt man eine "eee" “OU 4B IBAO fF ‘OU 4wo “QyUsIaM ssaoxny vIP'O (6280 |eL9°0 |9F'L 610 610 s¢°0 “qysram Apoq payor -100 Jo quad sad “F ‘ou yeO ZRST CLOSE CORR DO Fj GYAN peqyoem0o9 «= ‘fF 6Ou (—"URD zg9°9 03S |S90°6 O'SIE OVO € 090'E j\S6rs 6ST |°°° °° °° 4yBrea. oynTosqev ‘(qey quad tad 9g) p “ou 4B OPO |966°0 | FSF0 0's 9T'0 0 ¥Z'0 soresesss ss -qudraa Apog jo quoo sod ‘Z% ‘ou 4rQ OL8'7 2098 j\0PS'S 6°09 |066T |04b'S |€26°C. GIZL | gystom oynjosqe ‘(4uy quod sod $¢) g ‘ou 4BD ana |) Visit | vauonyal| AEAtt (a waned, | huwcawe| woanes| =0OR SWVUD NI NAAIO SLHDIGM TIY wIaT DALT *INASa IN TV¥LOL you 109 pup g ou yo ‘sunbuo pun fipog fo szybvam aanynjas pup ajnjosqy @ LUVYHO 74 EUGENE L. SETTLES of cat no. 4. Thus, subtracting 147 from 1729, the resultant fig- ure 1582 is obtained as the corrected weight of cat no. 4, which is 363 grams, or 30 per cent in excess of the weight of cat no. 2. Were the excess gastric and intestinal contents also subtracted, the figure would probably be lowered to about 25 per cent, which is about the average by which the heart and kidneys of no. 4 exceed no. 2. However, for safety, the figure 30 per cent is chosen for the table. With this new percentage excess as a basis, the percentage excess of the various organs of cat no. 4 over cat no. 2 are caleu- lated. By this means a truer estimate is arrived at of the actual effect of the difference in diet on the individual organs. It is seen from the corrected percentage table at the bottom of chart 2 that the organs may be divided into three groups:—1) those apparently affected by the difference in diet, i.e., the liver, the thymus, pancreas, and mesenteric lymph gland; 2) those which may have been affected by the difference in diet, i.e., femur and tibia, and, 3) those which were apparently not affected by the difference in diet, i.e., the kidneys, spleen, and heart. Dis- cussion is reserved until the microscopic findings have been given. MICROSCOPIC STUDY OF ORGANS FROM CATS NO. 2 AND NO. 4 The various organs were fixed in Zenker’s fluid for the most part. They were dehydrated in graded alcohols and aniline oil, cleared in xylol, imbedded in paraffin, and sectioned at 10 4 or 15 yu. Since this technique proved to be unsatisfactory in the case of the thymus, portions of this organ were imbedded in cel- loidon. Bouin’s fixative and the method of dehydration de- scribed by Allen (’19) were also tried, but the tissues treated in this way proved to be too hard to section well. The sections were stained with Mayer’s haematoxylin and eosin. The attempt was made, in each case, to secure specimens and sections from the two cats which corresponded as exactly as possible, as regards the part of the organ from which they were taken, the plane of sec- tions, and the technique employed. EFFECT OF HIGH FAT DIET ON LYMPHOID TISSUE 75 The chief object of the microscopic study was to find out the difference in the amount of lymphoid tissue in the lymphoid or- gans of the two cats. Measurements with the micrometer eye- piece were made of the sections of the different lymphoid organs of the two cats. However, the wide variation in the shape of these organs in the two cats and the uneven distribution of the lymph follicles and cords as well as the varying sizes and distri- bution of vessels, connective tissue, and spaces in the organs of the two cats make this method rather unreliable. The most satisfactory comparisons were derived from observation of the sections and from microphotographs taken at the same magnifi- cation. Liver. The liver of cat no. 2 (control) is apparently normal histologically. In contrast to this, the liver of cat no. 4 (fed on the high fat diet) is packed with fat globules of various sizes to such an extent that the whole liver structure is altered and its regularity destroyed. The cell structure is also changed by reason of the stored fat. The liver cells present a spongy appearance due te the presence in them of fat globules of various sizes. In many places the fat globules are so large that it is difficult to determine whether they are inside the liver cells or whether they are intercellular. The microscopic findings in the liver of cat no. 4 adequately explain the differences noted in the gross specimens of the two cats, especially the immense difference in the weight of the two organs. Pancreas. No significant histological difference was found in the case of this gland from the two cats. The microscopic study of the lymphoid organs will now be considered. Cervical lymph gland. The variability in shape and size of lymph glands makes comparison of the smaller glands unsatis- factory. Fortunately, the cat possesses an enormous mesenteric lymph gland, on which comparisons of size are feasible. The cervical glands, one from each cat, are selected as samples of smaller glands and are to be compared merely as regards relative distribution of lymphoid tissue, as seen with the microscope. 76 EUGENE L. SETTLES While the cortex of the gland from cat no. 2 is wider at one point than the cortex of that of cat no. 4 at its widest point, a glance at the figures of the two glands (figs. 1 and 2) shows that this gives an erroneous idea of the comparative amount of cortical substance present in the two glands. In cat no. 4 the cortex maintains a fairly even thickness throughout the entire cireum- ference—a thickness which in no place falls far below the maxi- mum. In eat no. 2 the cortical substance is either missing entirely or very narrow over approximately two-thirds of the circumference, being present only as two separated masses at the two ends of the section. Recognizable follicles are present in both glands. They are more numerous in the gland from cat no. 4, in which they are arranged fairly regularly around the cir- cumference of the gland, with an occasional follicle more deeply placed. In the medulla of cat no. 2 the cords are narrow and somewhat irregular, but in cat no. 4 they are much wider and more continuous. The sinuses contain many more lymphocytes in the gland from cat no. 4 than in that from cat no. 2. It is clear, from the comparison of the glands, that there is a definitely greater amount of lymphoid tissue in the gland of cat no. 4 than in that of cat no. 2. Pharyngeal tonsils. As may be seen in figure 4, a cross-section of the pharyngeal tonsil of cat no. 2, the lymphoid cells are some- what sparsely distributed in the reticulum. Two definite large solitary follicles are present. The lymphoid cells are more closely packed around the edges of these follicles than at any other place in the section. In the centers of the follicles the lymphoid cells are somewhat grouped together, leaving definite clear spaces between. In the pharyngeal tonsil from eat no. 4, figure 3, the lymphoid cells are much more closely packed together. The solitary fol- licles are crowded with lymphoid cells. There is a much larger amount of lymphoid tissue outside the follicles than in the gland of cat no. 2, and the lymphoid cells here are more closely packed together. The measurements of the lymphoid tissue of a typical cross- section of the pharyngeal tonsils are as follows: EFFECT OF HIGH FAT DIET ON LYMPHOID TISSUE 77 Cat no. 2, greatest length, 3.5 mm.; greatest width, 0.52 mm. Cat no. 4, greatest length, 5 mm.; greatest width, 1 mm. The approximate areas of the cross-sections are: Cat no. 2, 1.82 sq.mm., and cat no. 4, 5 sq.mm. Since the sections are through comparable parts of the glands and since care was taken to secure exact cross-sections, these figures give a rough estimate of the relative volumes of the two glands, namely, a proportion of 1 to 2.7. In view of the relatively greater density of the lymphoid cells in the gland from eat no. 4, it is probable that the pharyngeal tonsil from cat no. 4 contains in the neighborhood of three times as much lymphoid tissue as that from cat no. 2. Palatine tonsils. A comparison of these is somewhat unsatis- factory, owing to the difficulty of orienting them for obtaining corresponding sections. However, since their oval shape makes possible a cross-section perpendicular to the long axis, and by selecting the sections through the largest part of each gland, a fair comparison is secured. Two such sections, pictured in fig- ures 5 and 6, show the following. The section from cat no. 2 (fig. 6), is ovalin shape. There is a narrow open space in the middle, which represents the erypt which extends deep into the gland. Twelve solitary follicles may be counted arranged in a single marginal layer. The periphery of the follicles as well as the spaces between follieles are densely packed with lymphoid cells. Bordering the crypt, lymphoid cells are more densely packed than in the surrounding area. In the section from cat no. 4 (fig. 5) the erypt is shown extend- ing to the surface. There are twice as many follicles—twenty- four—as in the gland from eat no. 2, and they occur in two and three layers. The epithelium lining the erypt is invaded and, in many instances, largely replaced by lymphoid cells, which form a dense area near the lumen. The distribution of lymphoid cells is about the same as in cat no. 2. Measurements of sections of the two glands are as follows: Cat no. 2, greatest length, 3.4 mm.; greatest thickness, 1.8 mm. Cat no. 4, greatest length, 5.4 mm., greatest thickness, 2.5 mm. The areas of the two sections are in approximately the ratio of one to two for the sections from cats no. 2 and no. 4, respectively. 78 . EUGENE L. SETTLES Although these are only rough approximations of the size of the gland, all the data point to the gland from cat no. 4 as being very decidedly—probably at least 100 per cent—larger than the gland from cat no. 2, which, with a similar relative distribution of lym- phoid cells, means a decidedly greater total amount of lymphoid cells in the cat receiving the higher fat diet. Spleen. The sections shown in figures 9 and 10 are taken from the widest portions of each gland. In the section from cat no. 2 (fig. 8) a considerable number of red blood-cells may be seen scattered among the lymphocytes and other cells. The lymphoid cells are numerous and evenly distributed. The mal- pighian corpuscles are rather small and contain definite germinal centers. The section from cat no. 4, figure 7, contains a greater number of red blood-cells. The malpighian corpuscles are more numerous than in cat no. 2 and definitely larger. The germinal centers have about the same appearance as in cat no. 2, possibly not as distinct. It will be remembered that there was very little difference in the weight of the two spleens, considering the difference in the size and weight of the two animals. The microscopic study, however, shows a slight difference in the lymphoid tissue in the two cats. The spleen of cat no. 4 contains perhaps slightly more lymphoid tissue than that of cat no. 2, due to the increased num- ber and definitely larger size of the malpighian corpuscles. How- ever, the difference is hardly enough to justify the conclusion that the spleen has been modified by the difference in diet. Thymus. Figures 9 and 10 show the thymus gland of cat no. 4, and no. 2, respectively. These typical sections are very dif- ficult to compare microscopically, owing to the great difference in the shape and arrangement of the lobules. Moreover, a com- parison of the relative size of the medulla and cortex in the lob- ules is inaccurate as the section goes through the different lobules at different levels. In the section shown from cat no. 2 some of the lobules show a_ definite demarcation between cortex and medulla, while others show none, according to the part of the lobule cut through in the EFFECT OF HIGH FAT DIET ON LYMPHOID TISSUE 79 section. The cortex of the lobules is densely packed with lym- phoid cells, the medulla being comparatively free from them. In the section of thymus from cat no. 4 there are clearly more large lobules present than in cat no. 2. Whether the total num- ber is greater is very difficult to say, owing to the irregularities in size and shape. There is little difference in the relation of cortex to medulla in cat no. 4 as compared with cat no. 2. The place in the lobule through which one section passes affects this rela- tionship, as in cat no. 2. Apparently, then, the most important point in the microscopic comparison of the thymus of cat no. 2 and the thymus of cat no. 4 is the larger size of lobules found in the latter. Since the total weight shows a percentage excess for the thymus from cat no. 4 of 54.8, as shown in chart 2, and since the microscopic study shows lymphoid tissue to form at least an equal percentage of the entire gland, there is an excess percentage of lymphoid tissue of at least 50. Mesenteric lymph glands. The sections were taken through the enlarged part of the glands, at which place they were of about the same diameter. Both glands at this pomt contain two definite lobes, separated by connective tissue. Figures 11 and 12 show sections of the two larger lobes of cat no. 4 and no. 2, respectively. These two lobes are about the same size. In the’section from cat no. 4 we notice a decidedly great number of solitary follicles which are also larger and show a thicker and denser rim of lymphoid cells, as compared with the gland from cat no. 2. In cat no. 4 these follicles are found in the medulla as well as in the cortex. Few are seen in the medulla of the gland of cat no. 2. The cortex of cat no. 4 apparently con- tains more lymphoid tissue than that of cat no. 2, but the differ- ence is not great. However, the most striking thing about the sections is the comparison of the medulla. There is in cat no. 4 a greater area of medulla than in cat no. 2. The cords in the medulla are greater in number and decidedly larger and more continuous. Likewise, the sinuses cover a greater area and con- tain a great many more lymphocytes in the gland from cat no. 4 than are found in cat no. 2, where the sinuses are comparatively 80 EUGENE L. SETTLES free from lymphocytes. The two smaller lobes of cat no. 2 and cat no. 4 compare in practically the same way as the larger lobes. The comparison of these two typical sections, then, shows but little difference in the comparative area occupied by lymphoid cells in the two glands. The medullary cordsare larger and the fol- licles are larger and more densely packed with cells at the periph- ery in cat no. 4 than in cat no. 2. However, the extrafollicular accumulations of lymphoid tissue are perhaps greater in cat no. 2. Other sections of these glands were studied and showed simi- lar conditions. Since, however, the gland from cat no. 4 showed a percentage weight which was 22.7 per cent higher than that from cat no. 2, it is obvious that the percentage amount of lymphoid tissue present in the mesenteric lymph gland of cat no. 4 exceeds that of cat no. 2 by at least 22.7 per cent. Peyer’s patches (agminated follicles). By far the most striking difference found in any of the lymphoid organs was that found in the comparison of the Peyer’s patches, as seen through the microscope. Cross-sections of the long patch located in the terminal portion of the ileum are shown in figures 13 and 14 and parts of them shown again at a higher magnification in figures 15 and 16. A comparison of the dimensions of the cross-sections is as follows: Width of patch, cat no. 4, 7.5 mm.; cat no. 2, 5.2 mm. Aver- age thickness of patch, cat no. 4, 2.2 mm.; cat no. 2, 1.04 mm. Since this patch has been found in several cats to be of approx- imately the same length and of fairly uniform width, it is possible to estimate, from the two dimensions given, the relative volumes of the Peyer’s patches in cats no. 2 and no. 4. The areas of the cross-section are found to be: for cat no. 4, 16.5 sq.mm.; for cat no. 2, 5.4 sq.mm. It follows that the volume of the gland from cat no. 4 is three times the volume of the gland from cat no. 2. This is a far greater difference than has been found in any of the organs in which comparison by weight was possible. Moreover, a study of the sections shows an equally striking difference in the histological picture. The section from eat no. 2 shows a row of nine follicles, lying mainly between the muscularis mucosae EFFECT OF HIGH FAT DIET ON LYMPHOID TISSUE 81 and the circular muscle layer, with a fairly wide stretch of sub- mucosa intervening between the follicles and the latter. Toward the lumen, these follicles have projections, most of which end at the muscularis mucosae. A few of them break through this layer and extend out into the base of the villi, forming wedge- shaped structures. Between the follicles there is some lymphoid tissue in the half of the patch toward the lumen, while in the other half there is loose tissue. The villi over the patch are, in the main, normal appearing, save for the few whose bases are invaded by the wedge-shaped lymphoid projections, though perhaps they are slightly shorter than over the remainder of the mucosa. The section from cat no. 4 shows extraordinary differences. ‘There is about an equal number of follicles, but the individual fol- licles are enormously larger—in fact, as seen in figures 15 and 16, they may well be called gigantic—as compared with those from cat no. 2. The space at the submucosa between the follicles and the circular muscle layer is somewhat less than inno. 2. The follicles are packed with lymphoid cells. Toward the lumen, the muscularis mucosae is broken through at many more places than in no. 2, and the wedge-shaped projections into the villi are much larger and more numerous. ‘The villi over the patch are very short and wide, many containing a central mass of lymphoid tissue. The spaces between adjacent follicles are smaller than in no. 2, and are filled with lymphoid tissue in the half toward the lumen, as in cat no. 2. It is obvious that the proportion 1 to 3, found for the volumes of the patches, probably underestimates the relative amounts of lymphoid tissue, since the follicles are equally packed, while in no. 4, the projections through the submucosa are much greater and the spaces between the follicles much less. A very suggestive finding, also, was that of the presence on cat no. 4 of isolated follicles, separated from the Peyer’s patch, usu- ally one or two in each section. None were found in cat no. 2. This suggested that new follicles may have developed in cat no. 4 and led to a study of the lower ileum to determine how extensive this difference might be. THE ANATOMICAL RECORD, VOL. 20, NO. 1 82 EUGENE L. SETTLES Solitary follicles and lymphoid accumulations in the lower ileum. In order to obtain an estimate of the relative number and size of solitary follicles in the lower ileum, five blocks of intestinal tissue from cat no. 4 and six from cat no. 2 were examined. ‘The pieces, } to 1 em. long, were taken at various corresponding levels, from the lower third of the small intestine. The blocks were embedded in paraffin and cut transversely into sections 25 » thick. Every fifth section was saved. The results are as follows: Cat no. 4: block (1) 38} em. above caecum in 35 sections 6 solitary follicles Cat no. 4: block (2) 254 em. above caecum in 29 sections 19 or lymphoid Cat no. 4: block (8) 20} em. above caecum in 25 sections 17 accumulations Cat no. 4: block (4) 16 em. above caecum in 45 sections 35 Cat no. 4: block (5) 11 em. above caecum in 42 sections 61 MOtaliizeseeectn sents saad olala te RTS arene 176 sections 138 Cat no. 2: No. (1) 39 em. above caecum in 63 sections 0 solitary follicles Cat no. 2: No. (la) 32 em. above caecum in 46 sections Cat no. 2: No. (2) 25 em. above caecum in 56 sections 0 or lymphoid 0 Cat no. 2: No. (3) 20} em. above caecum in 55 sections 0 0 0 accumulations Cat no. 2: No. (4) 15 em. above caecum in 50 sections Cat no. 2: No. (5) 10 em. above caecum in 54 sections SPO UGl oie ciate he Ace es O era's Peintacs me sedis opens 324 sections 0 In estimating the number of follicles in cat no. 4, follicles ap- pearing in more than once section were counted once only. Peyer’s patches seen in some of the blocks from both specimens were disregarded. The ‘follicles’ seen in cat no. 4 vary from small accumulations of lymphoid cells, located outside the muscularis mucosae, to full-sized follicles, many of which project through the muscularis mucosae into the base of the villi. The result of this estimation is most striking. In the intestine of cat no. 2, 324 sections were examined, and no trace was found of lymphoid accumulations or solitary follicles, apart from Pey- er’s patches. In cat no. 4, in only a little more than half as many sections, 138 separate lymphoid accumulations or solitary folli- cles were seen, in addition to Peyer’s patches. This result is the most striking one which has been obtained and harmonizes with the study of the two Peyer’s patches. There can be no question EFFECT OF HIGH FAT DIET ON LYMPHOID TISSUE 83 but that the difference in diet is an exceedingly important factor in the regulation of the amount of lymphoid tissue in the intesti- nal wall. DISCUSSION AND CONCLUSION In reviewing the results of the experiments, it should be empha- sized that whatever effect may have been produced by the dif- ference in diet cannot be attributed unequivocally to the mere difference in the fat content of the diet, since there was also a difference in the amount of calories. The experiment, there- fore, shows the effect of a high calorie diet, in which the excess calories are provided by the fat of cow’s milk. With this defi- nitely understood, let us group together the results which have been obtained. A comparison of the weights of organs has shown that there has been produced, in the animal receiving the richer diet, an enlargement of pancreas, liver, thymus, and mesenteric lymph gland out of proportion to the enlargement of other organs, such as heart and kidneys. Gross appearance and the study of micro- scopic sections have also shown a striking enlargement of the lymphoid tissue along the digestive tract—of the palatine and pharyngeal tonsils—and especially of the Peyer’s patches and solitary follicles. Microscopic study and comparison of the ele- ments making up the lymphoid organs showed the lymphoid tissue to be either equally extensive or more extensive, rela- tively, in the cat fed the high calorie, high fat diet as compared with the control. The excess weight and size were found to be due not to stored-up fat (except in the liver), but to increase in lymphoid tissue proper. Therefore, it is obvious that, in lymph gland and thymus, with a decided excess in weight, and at least an equal distribution of lymphoid tissue, the high calorie, high fat diet has resulted in a very substantial increase in the amount of lymphoid tissue proper. In the two tonsils and particularly in the Peyer’s patches, all of which are made up of practically solid lymphoid tissue, the difference in size as seen in correspond- ing sections—and which amounts, in the case of the Peyer’s S4 EUGENE L. SETTLES patches, to a 200 per cent excess—indicates a decidedly larger relative amount of lymphoid tissue as a result of the higher diet. An exception is furnished by the spleen, which though a lym- phoid organ, shows no excess weight nor any marked increase in lymphoid tissue proper. It might be urged, in explanation, that the spleen is extremely variable in size in normal animals, as has been pointed out by Mivart (’98) and Hatai (’15), among others, and that a larger number of experiments might yield a result different from the present single experiment. However, this would be unjustifiable, considering the similarity of treatment of the two animals. It is only fair to conclude that the size of the spleen and the amount of lymphoid tissue contained in it have not been affected by the difference in diet. The very great excess increase in the thymus is of extreme interest. It has been found by many observers that the thymus is remarkably sensitive to undernourishment. Its response is so striking that Hammar (’05) has given the name ‘accidental hunger involution’ to the great reduction in size which occurs. Jonson (’09) found in rabbits, after four weeks of underfeeding, a reduction in weight of thymus to one-thirtieth the weight of the control. Jackson ('15) observed a loss of 90 per cent relative weight in the thymus of rats given a maintenance diet between the ages of three and ten weeks. Stewart (’18) obtained, in rats held at maintenance diet from birth to ten weeks, an 80 per cent loss in relative weight of the thymus. Jonson (’09) found an extremely rapid recovery rate on resumption of normal feed- ing, normal weight being reached after three weeks of normal diet following a period of undernourishment. The present study indicates that the thymus responds to a surplus diet, in which the surplus calories are supplied by fat, by a decided increase in size. It thus supplements and supports previous studies which shows the thymus to be particularly sensitive to differences in diet. The similarity in response of the thymus and of the lymph glands and lymphoid tissue along the intestinal tract affords evidence in support of the theory that the thymus should be grouped with lymphatie glands as a lymphoid organ. . EFFECT OF HIGH FAT DIET ON LYMPHOID TISSUE 85 The results furnish new evidence in support of the view, sug- gested at the beginning of the paper in the review of literature, that the lymphoid organs are concerned with metabolism— probably with fat metabolism—for they show a marked re- sponse to the high fat diet, along with the liver and pancreas, which are known to be specifically concerned with the storage and digestion of fat. In responding to an inereased function, or demand, for lymphoid cells, or lymphocytes, by an increase in size, the lymphoid organs would be merely following the well- proved law of functional adaptation, according to which increase in the function of an organ 1s accompanied by increase in size. Further studies should be made in order to analyze the two factors of high calorie and high fat, which have been combined in the present experiment, and also to test the effect on lymphoid organs of other dietary factors. However, whether the results have been caused by one or the other, or both, they are of value, for they show that these organs respond very decidedly to differ- ences in diet, by differences in size, which are far out of propor- tion to the relative differences in the size of the entire animals. SUMMARY Four kittens of the same litter and practically the same weight were fed on diets differing in fat content, with the purpose of discovering the effect of a high fat diet on lymphoid tissue. Two of the animals, one of which had been fed on a low fat percentage (0.7 per cent) and the other a high fat percentage (6 per cent), died at the end of three weeks. No appreciable dif- ference was found in the gross appearance or weight of the lym- phoid tissue of these two cats. However, microscopic examina- tion showed a noticeably greater amount of lymphoid tissue in the mesenteric lymph gland of the eat which had received the high fat diet. The other two kittens were kept for a period of four and one- half months, one on a normal fat percentage diet (33 per cent) and the other on a high fat percentage diet (6 per cent). They both remained in perfect health throughout the last three and a half months of this time. 86 EUGENE L. SETTLES Although the two cats started with the same size and body weight, at the end of the four and a half months the cat fed on higher fat diet weighed 510 grams more than the control, and was practically 30 per cent larger, excluding the amount of stored fat present. In the cat fed on a high fat percentage diet, the organs known to be concerned with fat metabolism and storage (the pancreas and liver) were noticeably larger, both by actual weight and per- centage than in the control specimen. In addition, the lymphoid tissue, with the exception of the spleen, was noticeably heavier in the cat receiving the high fat diet, the excess amounting to a difference of 85.8 per cent in the case of the thymus and 52.7 per cent in the case of the mesenteric lymph gland. In contrast to this, the heart and kidneys were only about 25 per cent larger in the larger animal. Microscopie examination of similar cross-sections from all the lymphoid organs of the two animals showed either an equal ora greater amount of lymphoid tissue per unit area in the cat which had been fed on the high fat diet. The difference was most strikingly shown in the case of the Peyer’s patch and the solitary follicles in the intestine. It is pointed out that the results obtained indicate that a com- bined high fat, high calorie diet produces a general enlargement of the lymphoid tissue of the body, which is most strikingly seen in the lymphoid tissue of the gastro-intestinal tract, but that they do not differentiate between the two factors—high calorie and high fat. An analysis of these two factors as well as the effect of other food elements should form the subject of further investigations. My sincerest thanks are due Dr. E. R. Clark for his invaluable advice and interest in the problem here presented. EFFECT OF HIGH FAT DIET ON LYMPHOID TISSUE 87 BIBLIOGRAPHY ALLEN, Ezra 1919 A technique which preserves the normal cytological condi- tions in germinal and interstitial tissue in the testis of the Albino rat. Anat Rece., vol. 16, no. 1, p. 25. BartTeL anp Stern 1906 Uber abnormale Lymphdriisen befunde und deren Beziehung zum Status thymico-lymphaticus. Archiv. f. Anat. und Physiol., Anat. Abt., S. 231. Crark, E.R. anp E.L. 1917 A study of the reaction of lymphatic endothelium and of leucocytes in the tadpole’s tail, toward injected fat. Am. Jour. Anat., vol. 21, p. 421. CzeRNEY 1907 Zur Kentniss der exudativen Diathese. Monatschr. f. Kin- derh., Bd. 6, 8. 1. FIESSINGER AND Marie 1909 Les ferments des leucocytes dans les exudats des séreuses. C. R. del. Soc. de Biol., p. 1062; also, Jour. de Physiol., eel ps 440: Hammar 1905 Zur Histogenese und Involution der Thymusdriise. Anat. Anz., Bd. 27, S. 41. Harar 1915 The growth of the body and organs in Albino rats fed with a lipoid free ration. Anat. Rec., vol. 9, p. 5. Jackson, C. M. 1915 Changes in the relative weights of the various parts, systems and organs of young Albino rats held at constant body weight by underfeeding for various periods. Jour. Exp. Zool., vol. 19, p. 135. Jenson, Avip 1909 Studien iiber die Thymusinvolution: Die Akzidentelle Involution bei Hunger. Arch. f. Mikr. Anat., Bd. 73, S. 390. KKANTHACK AND Harpy 1894 The morphology and distribution of the wander- ing cells of mammals. Jour. Physiol., vol. 7, p. 81. Kiscuensky, D. 1902 Zur Frage iiber die Fettresorption im Darmrohr und den Transport des Fettes in andere Organe. Ziegler’s Beitr., Bd. 32, S. 197. Mrvart, Sr. Grorce. 1898 The eat, p. 181. New York: Chas. Scribner’s Sons. Newton, R. C. 1919 A case of enlarged thymus gland and some remarks on status lymphaticus.. Amer. Jour. of Med. Sciences, vol. 167, p. 354. Povtain 1902 De l’action des ganglions lymphatiques sur l’absorption et la resorption des graisses. Revue mens. des Maladies de l’enfance, T. 20, p. 289. ; Scuirer, E. A. 1885 On the part played by amoeboid cells in the process of intestinal absorption. Int. Monat. fiir Anat. und Physiol., Bd. 2, 8. 1. 1912 Textbook of microscopic anatomy, pp. 396, 405, 521, 548, 551, 676, 681. New York: Longmans, Green & Co. Sturrpman, H. A. 1910 Histologische Untersuchung iiber die Beziehungen des Fettes zu den Lymphdriisen. Beitr. z. Path. Anat. U. Z. allg. Path. Jena, Bd. 48, S. 170-204. Srewart, C. A. 1918 Changes in the relative weights of the various parts, systems and organs of young albino rats under-fed for various periods. Jour. of Exp. Zool., vol. 25, p. 333. EXPLANATION OF FIGURES Figures 1 to 16 are microphotographs of histological sections of organs from eats no. 2 and no. 4. They are arranged in pairs—in each case the even num- bers (2, 4, 6, ete.) placed at the right, being taken from the organs of eat no. 2, the odd numbers (1, 3, 5, ete.) at the left, from cat no. 4. The two pictures shown in each pair were taken at exactly the same magnification. The enlarge- ment varies for the different pairs. The two pairs shown in figures 15 and 16 show, at a higher magnification, parts of the same sections as are shown in figures 13 and 14, respectively. PLATE 1 EXPLANATION OF FIGURES land2 Cross-sections of inferior cervical lymph glands, 104 thick. Figure 1, cat no. 4; figure 2, cat no. 2. ; 3 and 4 Cross-sections of pharyngeal tonsils, 10 4 thick. Figure 3, eat no. — 4; figure 4, cat no. 2. f 5 and6 Cross-sections of right palatine tonsils, 10 4 thick. Figure 5, catno. — 4; figure 6, cat no. 2. j 7 and 8 Cross-sections of spleen, taken at the widest parts of the organs, 10 thick. Figure 7, cat no. 4; figure 8, cat no. 2. ; EFFECT OF HIGH FAT DIET ON LYMPHOID TISSUE PLATE 1 EUGENE L. SETTLES 89 PLATE 2 EXPLANATION OF FIGURES ~ 9 and 10 Cross-sections of corresponding parts of thymus; embedded in celloidin, and cut 15 thick. Figure 9, cat no. 4; figure 10, cat no. 2. ; 11 and 12 Cross-sections of mesenteric lymph glands, 10 4 thick. Figure 11, eat no. 4; figure 12, cat no. 2. é 13 and 14 Cross-sections of the long Peyer's patch in the terminal ileum, 20 « thick; magnified 4.25 (approx.). Figure 13, cat no. 4; figure 14, cat no. 2. PLATE FFECT OF HIGH FAT DIET ON LYMPHOID TISSUE E SETTLES EUGENE L 91 PLATE 3 EXPLANATION OF FIGURES 15 and 16 Higher-power magnification of parts of same sections as shown in figures 13 and 14.; magnified 18 times (approx.), Figure 15, cat, no. 4; figure 16, cat no. 2. , 3 PLATE 3 EFFECT OF HIGH FAT DIET ON LYMPHOID TISSUE SETTLES EUGENE L. Resumen por el autor, Ivan E. Wallin, University of Colorado. Un caso de persistencia de la vena supracardinal izquierda con dos venas espermiiticas izquierdas. La descripcién de este caso consiste principalmente en una ilustraci6n de las variaciones venosas del sujeto estudiado. La porci6n inferior de la vena cava inferior consta de dos troncos. La vena espermitica izquierda esta representada por dos vasos distintos; uno de ellos comunica con la vena renal y el otro con la vena supracardinal izquierda, que persiste en este caso. Translation by José F. Nonidez Cornell Medical College, New York AUTHOR'S ABSTRACT OF THIS PAPER ISSUED BY THE BIBLIOGRAPHIC SERVICE, NOVEMBER 15 A CASE OF PERSISTENT LEFT SUPRACARDINAL VEIN WITH TWO LEFT SPERMATIC VEINS IVAN E. WALLIN Department of Anatomy and the Henry S. Dennison Research Laboratories, University of Colorado ONE FIGURE The occurrence of duplication of the inferior vena cava is not an altogether rare condition. In recent years Givens! has de- seribed two cases observed in the dissecting room of Cornell University Medical College, Ithaca. He also reviewed the lit- erature of some fourteen cases. The venous variant here recorded was found in a male cadaver in the dissecting room at the University of Colorado School of Medicine. There were no records of the age or the cause of death. The approximate age was sixty-five years. Figure 1 illustrates the lower part of the caval system in this subject. In character it is quite similar to the veins found in subject no. 466 described by Givens. The left persistent supra- cardinal is larger than in Givens’ subject. In his specimen the size ratio between the right and left supracardinals was 3 to 1.6. In my subject the ratio is about 2 to 1.5. An unusual feature in this subject are the two left spermatic veins. So far as I can learn this is the first recorded instance of such a condition. The figure shows the nature of the two veins. The one emptying into the renal vein was about one-third the size of the one emptying into the left supracardinal. The two veins were dissected out for some distance in the cord. With the exception of their proximal parts where they separate to empty into the above-named veins they lie close together in all of their course. 1 Givens, M. H., 1912. Duplication of the inferior vena cava in man. Anat. Record, 6: 475-486. 95 96 IVAN E. WALLIN The condition found by Huntington and McClure? in a human subject may help to explain the duplication of the left spermatie vein. They found fenestrae in the renal collar which estab- lished connections between the right spermatie vein and the right renal vein. By a further extension of the fenestrae along the vein a condition might be produced which would be like the character of the veins in this subject. 4B ct Supre- raydinal Vein 2 Personal communication from Professor McClure. oF ey a : { he Pe ele Loe ; Jat i ate ; a) ae Lil ie ane fh so | te | i eA we at ee Sees 7 way [hs pa? 4 e : < oe ei ba ye ys. 98 E. T. HSIEH Chinese writing, however, really dates from the time of the ‘Yellow Emperor,’ Huang-ti (3), 2697 B.C., who ordered his servant Tsang Chih (4) to make words in the form of imitative symbols. These were done in lacquer upon strips of bamboo or palm leaves. Paper and pens came much later. It is said that the vertical arrangement of characters was adopted because ~ it is much easier to write up and down a bamboo than around it. Many characters were elaborated during this period. We are told that Shen-Nung saw a good crop and made a character representing crop ears; that Huang-ti wrote a ‘cloud;’ Yao (5) a ‘turtle; Yu (6) the ‘bell and the kettle,’ and so on. The symbols devised represented pieces of string of different lengths with knots at various places in their course. Those consisting of a single knot with a small piece of string attached have sug- gested the name of ‘tadpole characters’ for this writing. These characters soon became profoundly modified. Figures 1 and 2 illustrate the pictorial type of the writing of the Hsia dynasty, 2205 B.C. A considerable change was also made about the beginning of the Chin dynasty (7), 255 B.C., when Li Si (8) greatly improved the terms and divided them into Ta Chuan (9) and Hsiao Chuan (10). Hsiao Chuan was changed to Chin Chuan (11) during this period. A little later Cheng Miao (12) devised a script called Li Shu (13), or plain square writing, which the first Chin emperor observed and ordered to be used throughout his empire. Paper was first manufactured at this time by Wang Lun (14). In the Han dynasty (15), 206 B.C., writing was further im- proved by Chia Fang (16), San Tsang (17), Tsai I (18), and Shih Ching (19), who wrote the word, Han Li (20), as may be seen by reference to figure 3. In the Chin (21) dynasty, 265 A.D., Chung Yin (22) and Wong Hsi Chih (23) changed the writing into a style more nearly approaching that of the present day. ‘Typical Chi-dynasty (479 A.D.) writing is well illustrated in figure 4, and this may be compared with the modern Chinese on pages 125-127. The works of Huang-ti (3), written over four thousand years ago, 2697 B.C., are the most interesting and original of the great 99 A REVIEW OF ANCIENT CHINESE ANATOMY SS BE LS KO S Cm an ORS GeO RP Aap} Bd, WS RE BE WE DIGS * 7X) ISR OE! Coe) SO PNT OX Bho ue 22 EE ow pio —— SSE wat KES e— gee PHA DOS 4445 0 wo) ea IFLE HEM GENT HO4KD Hq Ga ar|| ‘BD wy ap) 2205 B.C. sty, 2205 B.C. sty, 206 B.C. ty, 479 A.D. sty, Saas dyn Fig. 1 Old style of writing, Hsia Fig. 2 dyn writing, Hsia writing, Han Old style of dyns Fig. 3 Old style of n g, Chi dyna Fig. 4 Old style of writin 100 EB. T. HSIEH Chinese medical classics. They stand at the basis of native Chinese medicine. They were written on bamboo strips in words of the tadpole style as a record of questions which Huang-ti asked his servant Chi Pe (24). Later, in the Han dynasty (206 B.C.), they were gathered together into book form and were called Neiching (25) Internal Classics, Su Wen (26), Inquiries and Ling Shu Ching (27), The Classics of the Living Spirit. Un- fortunately, they were composed in such genuine literary style that they were difficult to understand until the time of Tang (28), in 620 A.D., when Wang Ping (29) wrote explanatory notes for each book. ; In the Chow dynasty (30), 1122 B.C., there lived an anatomist called Chin Yueh Jen (31), who wrote a treatise about the viscera and arteries and called it Nanching (32), or Hard Classics. This volume contains, among other things, a number of interest- ing measurements of the weights of the different organs of the men of that time. In the Han dynasty, 206 B.C., Chang Chi (33) wrote two books (34 and 35) on The Essentials of the Gold Medicine Case and on Fevers, which are very popular to this day. The Pre- scription for Emergency (36), by Ke Hung (37), appeared in the Chin period (38), 265 A.D. and, about two hundred years later, we meet with Chu Cheng’s (39) copy of the Testament (40). Many other authors follow, of whom we may mention Tsao Yuen Fang (41) in the Suei dynasty (42), 689 A.D.; Sun Si Miao (43) and Wang Show (44), in the Tang dynasty (45), 620 A.Dez and Wang Kun, Shen Kue, Chen Chi, Tang Chi, Liu Wen, Han. Ti, Pang An Shih, Cheng Ho Chung, Tang Shen, Wang Chu, Hsu Su, Chen Ssu Wen, Hsia Te, Chang Kuo, Chen Tze Ming, Chen Yen, Li Hsun, Yen Yung Ho, and Yang Chih Ying (46-64) —all in Sung dynasty (65), 960 A.D. Liu Wen Su, Chang Yuan Su, Chang Chung Cheng, and Li Hao (66-69) were prominent medical writers in the Chin (70) dynasty (1200 A.D.), and Wang Hao Ku, Sha-Tu-Ma-Su, Wei Ye Lin, Chu Chen Ting, Wang Kue Juei, Chi Te Chi, Tai Chi Tsung, and Wang Lii (71-78) in the Yuan dynasty (79), 1280 A.D. A REVIEW OF ANCIENT CHINESE ANATOMY 101 The name of Chang Chi Ping (80) is famed as a great anatomist in the Ming dynasty (81), 1368 A.D. Chang wrote a number of books. His most famous one he ealled Leiching (82). It dealt intensively with the visceral and vascular systems. Important advances were made in the Ching dynasty (83), 1644 A.D., when the Emperor Chien Lung (84) edited an Ency- clopedia of Chinese Medicine (85) and the government encouraged research. Sheng Teng’s (86) book on osteology (87) is replete with interesting observations. In the days of Chia Ching (88), 1796 A.D., a terrible epidemic raged among the children in the town of Chang Li Hsien (89) and many died. A certain magis- trate, named Wang Chui Jen (90), visited the public cemetery and found that, since the children were buried in very shallow graves, the hungry dogs were able to uncover the bodies and devour them. Wang’s curiosity was so stimulated that he went daily to the cemetery and observed over thirty complete bodies dismembered by the dogs. He was thus enabled to test out the old theories and to make important new observations which formed the basis for his book which he called A Correction of Faults in Medicine (91). At present anatomy is out of date in native Chinese medicine because the doctors only prescribe herbs for the patients and make no attempt at surgical operations. As it is impossible for me to attempt to review, in the space at my disposal, the whole of the ancient science of anatomy, I shall confine myself to a discussion of splanchnology, angiology, and anthropology. HISTORY OF CHINESE SPLANCHNOLOGY Splanchnology and angiology may be traced back to the time of Huang-ti, 2697 B.C. The two subjects were then more or less philosophically treated, and the theories advanced at that time have been handed down to us almost without change and constitute the foundation of native Chinese medicine to-day. Life is said to depend upon the action of a female principle which embraces a male principle. These principles are opposite powers of vigor or strength which are equal in weight. When 102 ER. T. HSIEH they are properly balanced there will be no disease of any kind and the person will be productive and healthy. These princi- ples are distributed quite differently in the body. The exterior is male and the interior female; the back male and the abdomen female; the viscera male and the parenchymatous organs are female. Each principle has three degrees in quality, namely, great female principle, female principle proper, and young female principle; great male principle, male principle proper, and young male principle (92-97). These three degrees of principle are evenly distributed in their respective organs and viscera. There are twelve tracts for the transmission of these prin- ciples in the general circulation. ‘Translating literally we read that: The hand receives the great female principle of the lung; the foot receives the great female principle of the spleen; the hand receives the female principle proper of the pericardium; the foot receives the female principle proper of the liver; the hand receives the young female principle of the heart; the foot receives the young female principle of the kidney. The hand receives the great male principle of the large intestine; the foot receives the great male principle of the bladder; the hand receives the male principle proper of the small intestine; the foot receives the male principle proper of the stomach; the hand receives the young male principle of the three burning spaces; the foot receives the young male principle of the gall-bladder. The three burning spaces referred to are situated in the thorax, abdomen, and pelvis and are illustrated in figure 13. They are supposed to be filled with fatty tissue. We read further, that, since the exterior is male and the interior female, then the male and female principles are as the coat and the lining (98). (Literally, great male and young female are the coat and the lining; male proper and young female are the coat and the lining; young male and great female are the coat and the lining.) The quality of the principles varies in different. organs and we have corresponding differences in the amount of air and of blood. The great male principle usually has much blood and very little air; the male principle proper has both blood and air A REVIEW OF ANCIENT CHINESE ANATOMY 103 in good quantity; and the young male principle has very little blood but much air. The great female principle has much air and little blood; the female principle proper has much blood but little air; and the young female principle has very little blood but much air. The liver (fig. 7), heart (fig. 5), spleen (fig. 8), lungs (fig. 9), and kidneys (fig. 16) are commonly called the five parenchy- matous organs, while the gall-bladder (fig. 15), stomach (fig. 14), large intestine (fig. 16), small intestine (fig. 11), bladder (fig. 12), and the three burning spaces (fig. 13) are regarded as the six viscera. The pericardium (fig. 6) and brain may also be referred to as organs. There are some differences of opinion about this, however, because Chi Pe, the servant of Huangti, 2697 B.C., claimed that the brain, bone-marrow, gall-bladder, and uterus are premanent singular bodies, which would indicate that the brain and bone-marrow may also be classified as true organs. The meaning of the term organ (99) is to store up, but not to eliminate, while the word viscera (100) means to eliminate, but not to store up. Huangti, 2697 B.C., describes in his book on Neiching, or Internal Organs, what the different organs store. We read that the liver (fig. 7) stores the blood, which contains the soul; that the heart (fig. 5) stores the pulse, which contains the spirit; - that the spleen (fig. 8) stores the nutrition, which contains the thoughts; that the lungs (fig. 9) store the breath, which contains the energy, and, finally, that the kidneys (fig. 16) store the germinating principle, which contains the will. He explains also his idea of their action. The liver has a rancid odor, a sour taste, a brown color, makes the sound chiieh (101), a note in Chinese music, and at will is the seat of anger. The heart has an odor of toast, a bitter taste, a brownish-red color, makes the sound chih (102), and at will is the seat of happiness. The spleen has a fragrant odor, a sweet taste, a yellow color, makes the sound kung (103), and at will is the seat of thought. The lung has a fishy smell, a hot taste, a white color, makes the sound sheng (104), and is the seat of sorrow. The kidneys (fig. 16) have a putrid smell, a salty taste, a black color, make the sound yu (105), and at will are the seat of fright. 104 Er. T. HSIEH ik JR NN A 45 KK H eS nes af 8 Fig. 5 Heart with three cords, as kidney, liver, and spleen (Huang-ti period, 2697 B.C.). Fig. 6 Pericardium. Fig. 7 Liver. Fig. 8 Spleen. A REVIEW OF ANCIENT CHINESE ANATOMY 105 These five organs are supposed to work harmoniously together and serve in the development of the body as follows: The liver produces the ligaments, forms the heart, and controls the lungs. The heart produces the blood, forms the spleen, and controls the kidneys. The spleen produces the flesh, forms the lungs, and controls the liver. The lungs produce the skin and hair, form the kidneys, and control the heart. The kidneys produce the bone-marrow, form the liver, and control the spleen. The five organs control the five senses and all parts of the body. » The liver has an eye at its opening, converts the fluid into tears, supplies the ligaments, and nourishes the nails. The heart has the tongue at its opening, converts the fluid into perspiration, supplies the pulse, and nourishes the complexion. The spleen has the mouth at its opening, converts the fluid into saliva, sup- plies the flesh, and nourishes the lips. The lungs have the nose at their opening, convert the fluid into snivel, supply the skin, and nourish the fine hairs. The kidneys have the ears as their openings and also the genito-urinary region, they convert the fluid into spittle, supply the bone, and nourish the hairs. The five organs are related to the six viscera which answer each other in their action (p. 103). The lungs relate to the - large intestine, which answers the skin; the heart relates to the small intestine, which answers the arteries; the liver relates to the gall-bladder, which answers the ligaments; the spleen relates to the stomach, which answers the muscle, and, lastly, the kidneys relate to the three burning spaces and the bladder, which answer the skin and the hairs. The functions of the organs and viscera are described as follows: The heart*is the king who directs the body, the lungs are the promulgators who carry out his orders. The liver is the general whose duty it is to meditate carefully. The gall-bladder is the central legal officer, who makes judgments. The pericar- dium is the minister to bring happiness. ‘The spleen is the officer of granaries who creates the five tastes. The large intestine is the officer of communications who starts all sorts of changes. The small intestine is the receiving office in which digestion is carried on. The kidney is the officer of vigor or strength who 106 EH. T. HSIEH E SRT HK itt Ba (i Ji fe |"| kg te 10 BFZAM REM) = BABE Tb | he HALKP Aris Hy. 11 12 Fig. 9 Lung with trachea (2697 B.C.). Fig. 10 Large intestine with the upper opening for the small intestine and the lower part for the rectum. ‘ Fig. 11 Small intestine with the upper and lower openings. Fig. 12 Bladder and urethra. A REVIEW OF ANCIENT CHINESE ANATOMY 107 serves through his intellect. The three burning spaces constitute the sewage system from which all the canals drain into the bladder where the fluid is stored; after having been acted upon by the air, it is finally passed out. The surrounding walls of the organs and viscera are also described: The thorax and abdomen constitute the city wall and the pericardium (fig. 6) is the palace of the king; the stomach is the granary and the throat and small intestine the post-office. The five openings of the stomach are called the doors, entrances and outlets (of the granary). Water and grain enter the body by the esophagus and air by the trachea. The food enters the stomach where essence soaks into it and it becomes air, which, if of nourishing nature, passes into the lower burning space. The air, entering at the trachea, passes through the epiglottis, which is the door of the voice. The mouth and lips arethe fan for the voice, the tongue the machine for the voice, and the uvula the pass for the voice. ‘The larynx divides the air. The breath, coming from the lungs, is thought to act upon the transverse bone (hyoid) and the tongue (in speaking). In the same book Huangti gives some measurements of the alimentary tract which will be of interest to anthropologists (see also p. 121).? Distance from lip to teeth... 21... ..0.sceesecseceoees $ inch VUCGLEGis TOD Light elt VOnap rite 5 Occ Or ORS EE aR A ae 24 inches Distance from teeth to epiglottis....................... 3} inches Capacity of mouth and pharynx...................... 5 Ko (106) Whelght ot tongue. co... art MESON: als ons c Sec eirwecis se 10 oz. PMN UNGL CONBUG a. cetene tes aati e ce maocs cc bik ee Fels eo 7 inches WIGG OM LON MU Grte Mredmen ta sastsiviecs «cies Gar Sev cnr elite 2} inches WGlGNG GMORODN MORN tice acca vm aciele Su cadédsocecbecs 10 oz. WIGUD OMenOpU RR U ee cne a earls seca wc os ac dcdoac cic aereeWs 0 1} inches Wien gUNiGn CHOPM EMU Rey eee pt lscewics ne daegaceens cnc 1 ft. 6 inches Length of stomach stretched out......................- 2 ft. 6 inches Circumference Ol AGOIMBGNS cxeadecciesiscs0 ceece smd iweaeye 1 ft. 5 inches WDpismoGver Ol: AbOMIAO aise sien cee te nice s ckir ass. soe ee 5 inches Capacity of stomach (dry measurement)............... 3 tou (107) 5 sheng (108) * Unfortunately, we cannot ascertain their equivalents in present-day stan- dards, E. T. HSIBH ae! Bu 7A BLAS . Bases ANSRE x SHt = 2 — = 13 15 16 Vig. 13 The three burning spaces (2697 B.C.). Fig. 14 Stomach. Fig. 15 Gall-bladder. Fig. 16 Kidney. A REVIEW OF ANCIENT CHINESE ANATOMY 109 Circumference of small intestine....... See boos s sre a CHES Diameter of small intestine. ...............-.... ..» fy Inch Length of small intestine................... . 33 ft. Capacity of small intestine (dry measurement) . Re rts 2 tou, 5 sheng Circumference of large intestine................ ...... 4 inches Diameter of large intestine................... ... 1} inches Dengthrorlargeintestinese .. <= <-50%= qc cccinmaswces pe OED, Capacity of large intestine (dry measurement)......... 1 tou @iraumlerence Of TEGHUMe). secs neic ee meee sds seees 8 inches PUIRAC EE OL ROCUIIs we ceiene tes Ee wel A ca'aetena dee ster 0 0 os 2} inches MOTTA GH OTR P AC UI Arse citiets td cw ey ate oew exes Br Tsao cms s 2 ft. 8 inches Gan aariMmCU TG CUO: fae stan femttaiete toe h min o nig sae.s oS 24 Ko The small intestine is attached to the spine posteriorily, and anteriorily to the navel. It exhibits sixteen loops. The large intestine lies on the left side of the navel and has also sixteen curves. In the book called Nanching, or Hard Classics, written by Chin Yiieh Jen in the Chow dynasty, 1122 B.C., we find the mor- phology and weights of the different organs and viscera described. It differs from Neiching in the following particulars: Liver, three left lobes and three right lobes........... 4 catties, 4 oz. Heart, seven holes and three pillars contains 3 Ko of MTSECOL OLE ECUNLCN TILE ciety. 7 x esis RRP © nsw ue, oid Meer 12 oz. Spleen, flat, 3 inches thick, 5 nches long, contains } catty of loosening extract......................... 3 catties, 3 oz. Length, eight lobes.................. tee ee eee 3 catties, 3 oz. ign eyes VMOU MUMOM. oc cceciiva sashes oe av cose tee 1 catty, 1 oz. Gall-bladder rests on the short lobe of the liver, con- fang oO Of Gasentiel Had sass... ses cee ae es 3 oz. 3 drams SHOMMGN cs. os deer co eaten USS nl RR eee eee 2 catties, 2 oz. PORE UCN UINO Nive at et Mele sR nn 3A suie a celles 2 catties, 14 oz. AEST EN ON ei errs sg wile arc. ds gins «bakisreis 2 catties, 12 oz. Bladder when stretched 9 inches long, contains 9 sheng, Qo) Geatinins ee get as FG rab ws a disease ees vc 9 oz, 2 drams Trachea, 2 inches wide, 1 ft. 2 inches long, in 9 sections 12 oz. FRGOUUIN set atau ame Inca wiciais acts acaign aint sieiple’s as 12 oz. In the Tang dynasty, 620 A.D., Sun Ssu Miao wrote two books in which he followed the descriptions given in the Nanching over 1700 years earlier with but slight modifications. However, the weights of the intestine and stomach and the length of the intestine differ somewhat from those given by Huangti in his 110 E. T. HSIEH BA WR FS Fig. 17 Surface anatomy, letters indicate the bones, front view (2697 B.C.). Fig. 18 Ditto, back view. Fig. 19 Ditto, side view. Fig. 20 Body measurements, front view. A REVIEW OF ANCIENT CHINESE ANATOMY 111 Neiching, 2697 B.C. Sun Ssu Miao described two bladders, one receiving the ‘essential fluid,’ and the other, fluid and urine. In his books each organ or viscus had attached to it the name of a protecting god. This indication of theocratism is not, how- ever, found in later writings on Chinese medicine. Controversy has been active regarding the three burning spaces (fig. 13) for upward of four thousand years. In the Nanching we read that the three burning spaces have no form, that they control the air (vigor), and that the two kidneys should be classed as two separate and distinct organs, the left being the real one and the right the ‘gate of life.’ The ‘gate of life’ is said, in the male, to contain the semen and, in the female, the uterus. This conception is entirely different from that advanced in the Neich- ing. Huangti, 2697 B.C., Wang Shu Ho (109), Huei Tsung (110) and Sun I Kuei (111), all contend that the burning spaces exist only in name, but not in form (108 and 109). The second theory assumes that the burning spaces exhibit definite structure. This view is actively supported by Hsii Tun (112) and Chen Wu Tse (113) in the Sung dynasty. The former observed a piece of fatty membrane, about the size of a man’s hand, near the bladder and two whitish cords emerging from it and running to the brain. He concluded that the membrane constituted the burning spaces (114). In the Ming dynasty, 1368 A.D., Yui Po (115) writes that the fatty membrane in the thorax also belongs to the three burning spaces. Chang Chi Pin holds the view that the thorax and abdomen are constructed like a large sac (116), that the inner lining is very red and that these linings are in truth the burning spaces. He debates the subject at length. According to a third theory, the three burning spaces are _eapable of subdivision into upper and lower parts governing corresponding regions of the body. ‘This idea is due to Li Kao (117) writing in the Yuan dynasty, 1280 A.D. (118-119). Later in the Ming dynasty, Ma Shih (120) described the three burning spaces as being a compound of two sets, one without form and the other with form. He says in his book (121) that the upper, middle, and lower burning spaces, described in Nanching, are 112 E. T. HSIEH bl 2 ak de 2 wet we MHA ~ ae * Fig. 21 Body measurements, back view (2697 B.C.). Fig. 22 Traveling vessels with their needling points, front view. Fig. 23 Ditto, back view. A REVIEW OF ANCIENT CHINESE ANATOMY 113 without form and filled with air, while the three burning spaces of the hand, foot, and young male have form. A few words may here be said about the term ‘Mingmen,’ or ‘gate of life’ (122), which is first used in the Nanching, 1122 B.C. The still older book I-Ching (123), originally written by Fuhsi (124) in 2852 B.C. and revised by Wen Wang (125) in 1122 B.C., says that ‘‘Keep in the learning of water, to which the kidney belongs, and you will be strong’ (126). Hoa-show (127) claims, in the Yuan period, 1280 A.D., that the air of the ‘gate of life’ connects with the kidney. We find that later, in the Ming period (1368 A.D.), Chao Hsia Ke (128) advanced evidence that the ‘gate of life’ is located at the needling point in the lumbar region, and further that female water belongs to the right kidney and male water to the left, between which there is a space of 14 inches. This area he believed to be the ‘palace of life’ from which the true fire, which is without form, is sent (129). But Sun I Kuei (130) expressed a different view, accord- ing to which the ‘gate of life’ is the original or mobile air of the body which plays between the two kidneys (131). Chang Chi Pin is a little more specific in his theory that the ‘gate of life’ corresponds to the orifice of the uterus where the kidney stores its essence. In Taoism this location is called “Tautien’ (132). According to still another view, the ‘gate of life’ is at the back opposite to and at the same level as the navel (133). All these conceptions indicate that the men of the time were trying to reverse the error of the Nanching which described the ‘gate of life’ as resident in the right kidney. Between the Sung and Yuan dynasties, 960-1280 A.D., there is but little improvement in the science of splanchnology. ‘The publication of Chao Hsien Ke’s (134) Morphological Atlas (135) and of Sun [I Keui’s book on Human Internal Organs (136), mark, however, a certain advance. Subsequently, in the Ching period, 1644 A.D., Feng Chiao Chang (137) reversed the teachings of Chao and improved his descriptions. In Feng’s book we read that the lung is attached to the third vertebra and hangs down in four lobes which are gray in color, that it possesses twenty-four lobes in order to provide for the circulation of air E. T. HSIEH 114 en slae miner PRUE HS aSzeul “eH fe Nuke Sati Ba eS (SS a eae tes RE ae NKBEA SW on a ae NY SD SESEES ERE aie \_ ... 6.5. cc. cssee ye ease 1 ft.2 inches Twelfth-rib Co mip-1Ointeter i. .- cs > sinc. cabtaewny pees ak 6 inches Hip to the middle of the knee... .. Renee Arr. asco 1 ft.9 inches Knee to external malleolus........... aca sete eee tenes 1 ft.6 inches External malleolus to caleaneus....................005- 3 inches Caloaneusitorerouttenmmen te da e'sis «ccaarcbte mar ch etter oem 1 inch Between ow See uu ants so sens slew ares v vialene strc eres 9 inches Bet weentuwo Garantie «oc .c. sna vaca thee rstnewe eames 1ft.3 inches Between two malar prominences..............0+-.00005 7 inches Betwoanthwo spe wie on «sinless cence ne ences ae 6} inches WOGilenaliey ree eaten 6 8 nnix's us yo ive foe Eee een 1 ft. 2 inches GGG Inn DE Sees), OP os x54 «ais sv eas Roe eee 4} inches Showldemtoveloow cet ccs... ss ceca cake asteulaen eee 1 ft. 7 inches WIDOWELOT IRAE a raiatere weiss. cx «4 aaa 7 on he Be 1 ft. 24 inches Wrist to first joint of middle finger.................... 4 inches First joint of middle finger to tip of finger. ............ } inch Border of hair of scalp to seventh vertebra............. 2} inches Seventh vertebra to sacrum... .. 5... cniuuenecccscenss 3 ft. In the Sung period, 960 A.D., the emperor ordered his phy- sicians to edit a system of medicine (173), in which we can find some further measurements, but unhappily the method of mak- ing them has not been described. We read that there are 365 bones in the male and five less in the female, that 190 of them are concealed so that they cannot be seen and that 256 possess bone-marrow. ; The works of Huangti remain perhaps the most complete on record. He is certainly to be regarded as the father of Chinese medicine. A REVIEW OF ANCIENT CHINESE ANATOMY 123 CONCLUSIONS It is quite evident from the foregoing account that in the beginning the science of anatomy in China was based upon actual dissection of the human body. The most notable evidence in favor of this conclusion is briefly as follows: Chipo, the servant of Huangti, 2697 B.C., writes that “after death the body may be dissected and actual observations made.” A little later we read that Yin Chow (174), 1122 B.C., killed Pi Kan (175) and dissected his heart to discover whether it had seven openings. In the Han period, 206 B.C., Wang Mang (176) slew Chen Hsun (177) and dissected his arm; the same gentleman also captured a revolutionary and ordered his physicians to dissect him. We find, also, that executions were frequently adapted to anatomical purposes. For instance, Liang Shao Pao (178), 960 A.D., sent his medical officer with an artist to make pictures during an execution of thieves, probably by the rather slow slicing process; and the local officer, Li I Hang (179), employed doctors and artists and labored himself to make dissections and to correct drawings during an execution at Ssu Chow. Yang Chik (180) compared these drawings with the old books, found them to be correct, and accordingly constructed his famous Allas of Truth. We have already mentioned the terrible epidemic which raged among the children in the town of Chang Li Hsieh in the days of Chia Ching (1796 A.D.), and of how a certain magistrate, named Wang Chin Jen, happened to visit the public cemetery where he found that hungry dogs were uncovering the bodies, hastily buried in shallow graves, and devouring them. Wang's curiosity was so aroused that he went daily to the cemetery and observed over thirty complete bodies dismembered. He was thus enabled to test out the old theories and to make important new observations which formed the basis for his book called A Correction of Faults in Medicine. Unfortunately, this direct method was soon replaced by a rule of authority somewhat similar to that which reigned in Europe 124 E. T. HSIEH before the Renaissance. For instance, The Essentials of a Gold Medicine Case and a book on Fevers, written by Chang Chi in the Han dynasty (206 B.C.), remain very popular to this day. With the reintroduction of direct observation and a true appre- ciation of the value of experimental methods, we may look for great advances. A REVIEW OF ANCIENT CHINESE ANATOMY 125 % Bibliography ve) # fk « Fi $8 ef £0 2 4 B&F a BR 4&7 As) A Ait AR A sun ssu Miao (620 A.D.) oR I Bz Re Huangti (2697 B.C.) Huengti (2697 B.C.) Huangti (2697 B.C.) - Chin Ytleh Jen (1122 B.C.) Huang Pu Mi (265 A.D.) Wang Su Ho (265 A.D.) Sun Ssu Miao (620 A.D.) Wang Tao (620 A.D.) Sun Ssu Miso (620 A.D.) Suhuangmen (960 A.D.) Chen Wei Tsai (960 A.D.) Sung period (960 A.D.) Wang Heo Wen (1280 A.D.) Rue Show (1280 a.D.) Yu Fu (1368 A.D.) Chang Chi Pin (1368 A.D.) Ma Shih (1368 A.D.) Chao Hsie Ke (1368 A.D.) Sun I Kuei (1368 A.D.) Yang Chi Chow (1368 A.D.) Feng Chiao Chang (1644 A.D.) Chien Lung (1736 A.D.) Wang Ching Jen (1796 A.D.) Peng Tsung Hai (1875 A.D.) a So ge ee sees Hi Boks Se NR [neh eM RE Ke Sp ee ee Ry > o so AM Be NS & ss by HH Sa, Be ae a & N. Tr Fe AR A 4a 5h A XY te & Ay FR tay at 4h 1 BF e- *. 91 # th GX 4 121 Wf £4 k 151 fp ME AR 92 4. we 122 fp \') 152 par ft AK 93 fen PS 123 1) £4 153 A i) Ut op 94 +} P& 12a tk & 164 Bf 2 ih & 95 A PD 126 < 155 ZA He, we 96 pS vf 126 FE Se 2g, 156 5% a7 pp 127 jt 1s7 A> 98. fe 128 ARK 158 99 Aix, iw ¢£ 159 4, R 100 AKt 130 3% — 160 % wi) A 101 dh 131k 4 £ AS 161 + & E—= 102 4¥L 132 # @ 162 = # 103 ‘2 133 #5 6% pt R 163 SRE PLE 104 jig 134 APE 164 4= 2 105 i) 135 #5 it fee ole — 106 /> 136 ib Eh 166 j4 Bit 107 + 137 4G IE 5 167 4 + 108 + ise 4pR RAR 168 fA AX ANE B 109 E42 fu 139 $4 Pi 169 49 BK E llo Ake ¥ 140 /S & Hp 170 #5 4 on 11. 34 —-4% 141 HF vo 1m 4X % KIX ne ¢ 2 As i 172 44 & 113 pp se +¥ 148 f oe FUE HX 173 Ay 48. BR 114 HAC Aspe AE AE AG Have gg st 15 jf th 145 FAK 175 Li + 116 #) st pit B 146 (Ef MR 176 5 17 + 2 147 ER ye 177 $4 vie ul ¥ HG x a8 A iw 178 fh ; 4h 119 ZY 43 149 pS WS eR 170 f & ¢; 120 i it 150 PB WS We 1so #2 i 127 THE ANATOMICAL RECORD, VOL. 20, No. 2 Resumen por el autor, Oliver H. Gaebler Universidad de Missouri. E] epitelio de la vejiga durante la contraccién y la distensi6n. El presente trabajo trata del problema de si durante el proceso de distensi6n fisiol6gica, el numero de capas celulares del epitelio de la vejiga permanece constante o, por el contrario, si disminuye, es decir, si las células epiteliales simplemente se aplanan o si se disponen en un nimero menor de capas. En los estudios llevados a cabo, el autor ha empleado material procedente de ratas, conejillos de indias, y conejos, pero el trabajo mids impor- tante fué hecho en conejos. Para resolver el problema se han empleado dos métodos. El primero consiste en contar el niimero de capas del epitelio en vejigas en diversos grados de distensién, comparando dichas capas con el ntimero encontrado en vejigas contraidas. El segundo método empleado depende del hecho de que si no hay una disposicién de las células epiteliales en un ntiimero menor de capas, la relacién que representa el aplanamiento del epitelio en cualquier direccién debe ser idéntica a la que representa el aplanamiento de sus células en la misma direccién. Estas relaciones se determinaron mediante medidas del epitelio y de diez mil células, en dos series de vejigas de conejos. Las conelusiones obtenidas por ambos métodos son: 1) La distensiOn fisiol6gica moderada no disminuye el ntiimero de capas de células epiteliales; 2) La distensién fisiologica maxima no disminuye las capas citadas en mas del 12.5 por ciento; 3) Las células de las capas mis profundas no estin unidas tan intimamente conto las de las capas superficiales, y 4) Las células no sufren una contraccién ulterior después que ha comenzado el plegamiento del epitelio. Translation by José F. Nonidez Cornell Medical College, New York AUTHOR'S ABSTRACT OF THIS PAPER ISSCED BY THE BIBLIOGRAPHIC SERVICE, NOVEMBER 15 BLADDER EPITHELIUM IN CONTRACTION AND DISTENTION OLIVER H. GAEBLER Anatomical Laboratory, University of Missouri NINE FIGURES The main problem with which this paper deals may be stated in the following questions: Does the epithelium of a bladder in distention have the same number of layers of cells as the epi- thelium of a similar bladder in contraction? Does the process of distention involve only astretching of the cells, or also an arrange- ment into fewer layers? This problem has been discussed for many years. London (81) studied the relation between thickness of the epithelium and degree of distention of the bladder, because he believed that data obtained would be of interest in connection with the prob- len of resorption of substances from the urine. Since the epi- thelium of the bladder forms a barrier between the contained urine and the capillaries in the underlying connective tissue, the thinning out of this epithelium on distention was thought to be significant in connection with the stated problem. In regard to the number of layers of cells, London (’81) said that there was an apparent diminution during distention, but an actual diminu- tion only in the number of layers of nuclei, and not in the number of layers of cells. Dogiel (90) studied the histology*of bladder epithelia of mice, rats, and various other mammals, and claimed that the cells of the first two layers, counting from the surface layer, were so interlocked by protoplasmic processes that there was no possi- bility of a change in their relative position occurring during disten- tion. Eggeling (’01—’02) and many others published articles on the histology of bladder epithelium, but did not touch upon the 129 130 OLIVER H. GAEBLER problem under discussion in this paper. Harvey (’09) described the variations in all the layers of the walls of both bladder and ureter during contraction and distention. In regard to the blad- der epithelium, he says that there is a decrease of 50 per cent in the number of layers of nuclei during distention, and also a decrease in the actual number of layers of cells. Concerning the human bladder, one histologist (Lewis and Stéhr, 13, p. 324) says the following: ‘‘ The epithelium has been described as two-layered in the distended bladder, the outer cells having terminal bars; in the contracted condition it becomes several layered, and the bars form a net extending into the epi- thelium. Thus it is not believed that during distention the lay- ers merely flatten; they are. thought to ‘slip by each other.’ The columnar cells may, however, become extremely flat.” The various observers, using material from many sources, and employing numerous methods, have, therefore, reached several conclusions that bear upon the particular problem here discussed. Some of them have pointed out the decrease in the number of layers of nuclei in bladder epithelium during distention and have determined this decrease quantitatively. Some have stated that while there is a decrease in the number of layers of nuclei, there is no decrease in the actual number of layers of cells. Others have claimed that there is an actual decrease in the num- ber of layers of cells during distention, but have made no state- ments regarding the extent of this decrease. The following studies were therefore made for the purpose of finding out whether there is any diminution in the number of layers of cells during distention, and, if so, how great the diminution is. MATERIALS AND METHODS ~ In the experiments that follow the animals used were white rats, guinea-pigs, and rabbits. The preliminary work,'done on some material from each of these three sources, suggested that the results would be very much alike, if not identical, for the three animals, and since rabbit material seemed the most favor- able for the particular methods of procedure and _ staining required, the final work was done on rabbit material. CHANGES IN BLADDER EPITHELIUM 131 In obtaining bladders in various degrees of contraction and distention, it is evident that the more nearly normal, or physio- logical, the process of contraction or distention, the less open to objection is the result. Bladders in various degrees of normal distention or contraction can be obtained by simply taking ani- mals from their cages, killing them at once, and relying on chance. If chance killing does not yield a sufficient number of contracted bladders, female rabbit bladders can be made to contract by pres- sure on the lower abdomen or by irritation of the urethra. With male rabbits the pressure method is less reliable. If completely contracted bladders are wanting, they can be produced by cutting the urethra or opening the bladder in any way, in an animal that has just been killed. If greatly distended bladders are desired, the animals are given an abundance of water, taken from their cages and played with or excited in any way for thirty minutes to an hour, and suddenly killed. To fix a bladder found in partial or complete distention, the urethra and ureters are clamped with one hemostat immediately after the abdomen has been opened, and are then cut on the side of the hemostat away from the bladder, so that the urine is retained. The bladder is then immersed in saturated mercuric chloride solution for two or three minutes. This destroys the contractility of the muscle cells. In guinea-pigs a longer exposure was needed to accomplish this result. The bladder is next trans- ferred to physiological salt solution, cut open, washed out in several changes of salt solution if necessary, and returned to mercuric chloride solution for twelvé hours. In completely contracted bladders, the part used for sections is a cylindrical piece secured from the middle of the bladder by two parallel cuts, made at right angles to the long axis of the bladder and 2 or 3 mm. apart. In partly or completely dis- tended bladders, a corresponding equatorial zone, about 5 mm. wide, is cut out after fixation. This zone is cut open anywhere, measured just before imbedding, and cut into a convenient num- ber of pieces, all of which are imbedded. The solution of the problem depends fundamentally upon an unmistakable staining of the cell boundaries. Such staining will 132 OLIVER H. GAEBLER prevent overlooking of cells whose nuclei are not included in the section, and will enable one not only to count the number of layers of cells, but also to measure accurately the size of the cells. A number of staining methods were tried, but it was found that the following iron hematoxylin methods, when used with rabbit material, were the most successful: First method. 1, Fix ina saturated solution of mercurie chlo- ride in physiological salt solution. 2. Stain with freshly prepared Hansen’s hematoxylin to which no sulphuric acid has been added (Lee, ’13, p. 159) until the sec- tions are very black. This requires fifteen to thirty minutes. Decolorize in 2.5 per cent iron alum solution, to the point where cell boundaries show plainly, paying no attention to the layers of the bladder wall other than the epithelium. Clear and mount without counterstaining. Second method. Mallory’s chloride of iron hematoxylin method, as described in Mallory and Wright’s ‘Pathological Technique,’ page 310. In differentiating, again watch the epithelium only. Although the solution of the problem depends fundamentally upon the success of the foregoing procedures, one very important complication remains. Due to the complexity of the folding of the epithelium of completely contracted bladders, sections taken at right angles to the long axis of the bladder will be perpendicu- lar to the epithelium at only a few points, and tangential every- where else (fig. 9). This difficulty is avoided by securing bladders that have contracted just to the point where folds begin to form, and fixing them in this condition by the method previously de- scribed. Sections can then be obtained that run perpendicular to the surface of the epithelium, just as carefully prepared sec- tions of distended bladders do. This simplifies the entire prob- lem a great deal. Although important results were obtained from rat and guinea- pig material, the results obtained from six rabbits will cover all the facts ascertained, so it will be best to give the details of this part of the work, and pass by the remainder to avoid repetition. Six rabbits, all of the same litter, all female, and a little less than half grown, were dealt with as follows: CHANGES IN BLADDER EPITHELIUM 133 Rabbit no. 1. Weight, 26 oz. The rabbit was well supplied with water, Tuesday, January 6, 1920; taken from cage at 8:30 p.m., played with for half an hour, and killed by a blow at 9 p.m. The abdomen was opened. The bladder was found widely distended, was clamped off, removed, and suspended in bichloride solution for two minutes. Its equator measured 10.4 em. Jt was suspended in normal saline while the base was cut off. No contraction followed. The -bladder was washed out and replaced in bichloride at 9:10 p.m. Rabbit no. 2. Weight, 26 0z. This rabbit was taken from the cage, January 6, 1920, 9:15 p.m. Pressure was put upon the lower abdomen at once, and resulted in passage of a small amount of urine. The ani- mal was left for a minute, and was then killed by a blow. The abdo- men was opened, and the bladder found completely contracted, The bladder was removed, washed out with physiological salt solution, and put in bichloride at 9:20 p.m. Rabbit no. 3. Weight 26 oz. This rabbit was killed Saturday, January 24, 1920. The procedure and results were very similar to those for rabbit no. 1, excepting that the distention was smaller. The equator of the bladder measured 8.2 cm. Rabbit no. 4. Weight, 26 0z. The rabbit was killed Saturday, Jan- uary 24, 1920. Procedure and results were very similar to those for rabbit no. 2. The bladder was not found completely contracted, but contracted completely when the base was cut. Rabbit no. 5. Weight, 24 .0z. The bladder of this rabbit was partly emptied by pressure on the abdomen. The animal was then killed by a blow, and the bladder was found partly contracted. It was clamped off and removed, suspended in bichloride three minutes, suspended in normal saline while the base was cut off, and was then washed out. The folds in the epithelium had just begun to form in one region of the bladder. The bladder was replaced in the fixative within ten minutes after the death of the animal, January 26, 1920. Rabbit no. 6. Weight, 24 0z. The rabbit was killed on February 1, 1920. The procedure and results were practically identical with those for rabbit no. 5. The sections were all cut 10u thick. While this is thicker than is usually recommended for the methods of staining used, staining of cell boundaries in the epithelium is in no way interfered with, and sec- tions of this thickness were valuable because the relations in any one hoo plane could be more firmly established by focusing at various epths. RESULTS OBTAINED BY COUNTING THE NUMBER OF LAYERS OF EPITHELIAL CELLS After all these specimens had been sectioned, two methods of approaching the problem were used. The first, and most obvi- ous, was simply to count the number of layers of cells in the epi- 134 OLIVER H. GAEBLER thelia of the various bladders. In the completely contracted bladders, with complexly folded epithelia, the number of layers varies a great deal, due to the great number of places where the section is tangent. But at frequent intervals the number of layers is three to four, and if the number of layers is approxi- mately the same over the entire bladder, these places must be the points where the section is cut perpendicular to the surface of the epithelium, and hence the points giving the correct num- ber of layers. The number of cells in sections from bladders that had contracted just to the point where folds began to form was also counted, and in these there were regularly three to four layers. The number of layers in the distended bladders was also three to four. In all cases the variation was slightly greater than this, for there were points at which only two layers of cells could be distinguished, and others at which there were no less than six layers, but three to four layers constituted the most frequent thickness. The sections were studied under oil immersion, at a magnifica- tion of 950. With this magnification, the cell boundaries stained by the indicated methods stand out with surprising clearness, both in the contracted and in the distended specimens. Low magnifications proved very deceptive. Several of the figures illustrate the mistakes most easily made in counting the number of layers of cells. Figure 1 is a camera-lucida drawing of a portion of one of the sections from the distended bladder no. 1. At lower magnifica- tions one would readily suppose that, counting down from the large surface cell, at the point indicated by the arrow, there were in all three layers. But at higher magnifications it is clearly seen that there is a junction of the two cells lying beneath this surface cell, and that there is a cut edge of a basal layer cell just above the nearest connective-tissue nucleus; so the number of layers in this region is five. Focusing down, the slip seen at the base in the focal plane of the drawing develops into a nucleated cell. The method of counting nuclei was not found serviceable in determining the number of layers at any given focal plane. This is shown in figure 2, which is a camera-lucida drawing of a CHANGES IN BLADDER EPITHELIUM 135 portion of a section of the distended bladder no. 3. If one de- pended upon the nuclei, the number of layers would vary between two and one. But here again the edges of cells cut outside of their nuclei make the variation one between three and four layers. It should also be mentioned that if a line is drawn perpendicular to the surface of the epithelium at (a), it passes through four cells, tao EE at Fig. 1 Camera-lucida drawing of portion of epithelium of distended bladder no. 1 (X1128). The arrow marks the point at which the five-layered epithelium is easily mistaken for a three-layered one. Fig. 2 Camera-lucida drawing of portion of distended epithelium of bladder no. 3 (X1128). The layers of nuclei vary between one and two. Actual layers of cells vary between three and four. but the number of layers is really only three, since the last two cells through which the line passes are really in the same layer, the boundary between them being diagonal. Figure 3, a camera-lucida drawing of portion of the epithelium of distended bladder no. 1, again emphasizes the fact that in this series of studies the method of counting nuclei had to be aban- 136 OLIVER H. GAEBLER doned, because the number of layers of cells was the information desired. It also presents another example of the importance of counting cells whose cut edges might easily escape notice at low magnifications. In the region (A) the epithelium might easily be mistaken for a two-layered one, because the small cut edge of a second layer cell and the surface cell are about equally granular — Fig. 3 Camera-lucida drawing of portion of the distended epithelium of blad- der no. 1 (X 705). The figure shows the importance of counting portions of cells not containing nuclei, such as those in the region A, when estimating the number of layers. Fig. 4 Camera-lucida drawing of portion of the epithelium of contracted blad- der no. 6 (X 705). This figure shows two places at which_the contracted epi- thelium is only two layers thick. and appear about the same shade. But a fine, distinet cell boundary separates them. When all these precautions are observed, there will still be some points where the distended epithelium appears to be only two layers thick. But, turning to the bladders that have con- tracted to the point where folds just begin to form, we will find CHANGES IN BLADDER EPITHELIUM 137 quite as many places where the epithelium is only two layers thick. Figure 4 shows a piece of contracted epithelium, and at two places in the’ figure there are only two layers of cells. There is evidence that the cells in the epithelium are bound to their neighbors pretty firmly. If one examines the various figures of contracted and distended epithelium shown in this paper, it is noteworthy that in the distended bladders the cells are still bound to their lateral neighbors along a considerable distance. In the surface layer these boundaries between cells may run perpendicu- lar to the surface or at almost any other angle, but the length of the boundary bears about the same relation to the greatest thick- ness of the distended cells as the lengths of the boundaries be- tween surface cells in the contracted epithelium bear to the great- est thickness of the cells in contraction. The surface cells with basal processes are also interesting objects in this connection. Figures 5 and 6 show portions of two bladders, one in contraction and one in distention, in which there is a comparable, though not’ identical relation of such cells. ‘The three cells in the second layer, in the region between (A’) and (B’) of figure 6, bear about the same. relation to the large surface cell in this region as the three second-layer cells in the region between (A) and (B) in figure 5 bear to the contracted surface cell with the basal proc- esses. And the significant point in the figures is that the sur- face cell in figure 6, though distended to the great length of 95.74 still has points along its lower border that suggest remnants of basal processes. Considering the degree of distention of this surface cell, one would expect its lower boundary to be more nearly straight, if there were not a firm attachment of the lower cells that exerted a tension at the two points where the most marked irregularities exist. Sections of the extensively folded epithelium of completely contracted bladders are also interesting subjects for study. On the crest of a fold; a section through the epithelium will fre- quently have the appearance shown in figure 7. The appear- ance of the surface cells is that of partial distention, as though they had been stretched by the pushing in of the fold. 138 OLIVER H. GAEBLER In the bottom of the pits, or rather troughs, between folds, the cells frequently have a columnar appearance. ‘This is shown in figure 8. In the middle of the piece of epithelium shown, this columnar appearance is not only apparent, but real, while at the borders the figure is misleading, because the epithelium is rotated through ninety degrees from the position in which it is usually figured. Pig. 5 Camera-lucida drawing of portion of the epithelium of distended blad- der no. 6 (X 705). The surface and second-layer cells in the region between A and B bear a relation to one another similar to that of the corresponding cells in figure 6, in the region A’ to B’. Fig. 6 Camera-lucida drawing of portion of the epithelium of distended bladder no. 3 (X 705). Note the projections on the lower surface of the large surface cell, suggesting remnants of basal processes. The first method of approaching the problem under discussion —the method of simply counting the number of layers of cells in any given focal plane—therefore results in the conclusion that the range of variation in the number of layers in the contracted bladder is about the same as in the distended bladder. The usual number of layers in both is three to four, and in either CHANGES IN BLADDER EPITHELIUM 139 contracted or distended bladders there may be places where there are only two layers or where there are more than four. This method of stating results still does not give completely the in- formation desired, for the question remains: Does the contracted bladder contain more area covered by four layers and the dis- tended bladder more area covered by three layers? If there is Vig. 7 Camera-lucida drawing of the epithelium at the crest of a fold in com- pletely contracted bladder no. 2 (X 422). Note the partially distended appear- ance of the surface cells. Fig. 8 Camera-lucida drawing of the epithelium in a trough between folds of completely contracted bladder no. 2 (X 422). Note the columnar appearance of the cells. such a difference, it is not so noticeable as to be at once agreed upon after studying two comparative sections. So at this point the second method of inquiry, depending upon cell measure- ments is brought in. 140 OLIVER H. GAEBLER METHOD OF CELL MEASUREMENTS, AND ITS RESULTS It is evident that if all of the stretching of the epithelium is to be accounted for by stretching of the cells, and not by ‘slipping’ or rearrangement into fewer layers, the ratio that represents the stretching of the epithelium in any given direction should be identical with the ratio that represents the stretching of the cells in this direction. The amount of stretching of the epithelia was determined as follows: After fixing, as stated before, an equatorial zone, 3 to 5 mm. wide, was cut from the distended bladders and from those that had contracted to the point where folds just began to form. These zones were cut open along any meridian, thus converting them into ribbons, the length of which, measured just before imbedding, gave accurate results as to the length of the epi- thelium in the completely distended bladders. The ribbon-like strips were then cut into a convenient number of pieces, all of which were imbedded. Sections were cut perpendicular to the surface of the epithelium and parallel to the equator of the blad- der. By projecting a section from each block of any particular zone, and measuring it with a wheel tracer, the length of the com- plete epithelium—i.e., the circumference of the circle which it forms in a complete section perpendicular to the long axis of the bladder at the equator—was calculated. The lengths of the cells were then measured, in the direction parallel to the surface of the epithelium, in the same sections. It is evident that if there has been no slipping, the ratio of contracted to distended cells should be the same as that of contracted to distended epithelium. It must be borne in mind that the quan- tities here compared are linear quantities, and not areas, and that like dimensions, and not squares of like dimensions, are therefore compared. Completely contracted bladders cannot be ccna with greatly distended ones by this method, because of the impossi- bility of obtaining accurate information in regard to the length of the epithelium in the completely contracted bladder. When the folds of the epithelium first form, they are fairly regular CHANGES IN BLADDER EPITHELIUM 141 longitudinal, or rather meridional, folds. But on further con- traction they become very irregular, probably due to the fact that the longitudinal muscle layer, contracting, carries with it the tunica propria that runs into these already formed folds. Vigure 9 illustrates this point. It is a sketch of a portion of the epithelium of a completely contracted bladder in surface view. The bladder was found completely contracted in a freshly killed adult rabbit. Base and apex were cut off, and the bladder was DS yy 4, A 9 Fig. 9 Free-hand drawing of epithelial surface of completely contracted bladder (X 7.5). The vertical direction of the drawing is meridional with respect to the bladder. The figure shows that transverse sections may pass through the same fold three times. cut open along a meridian. It was then spread out flat, with the epithelium uppermost. The corners were pinned down, and the specimen hardened in bichloride solution. A small square piece was cut out and sketched. The vertical direction of the drawing as here shown is longitudinal with respeet to the bladder. It is easily seen that a section running at-right angles to the long axis of the bladder might cross the same irregular longitudinal fold three times. Consequently, when the sections are studied, it is impossible to decide whether a given fold has been produced 142 OLIVER H. GAEBLER by meridional or by equatorial contraction. To measure the length of the surface of the epithelium in sections across a com- pletely contracted bladder is therefore useless. This was noticed during the preliminary work on this problem. The length of the contracted epithelium, multiplied by the amount of stretching observed in the cells, far more than accounted for the length of the distended epithelium. ‘This was true even though all masses of epithelium within the main lumen, or all separate portions of the lumen not connected with the main lumen in the section, were left out of consideration. The measurement of the length of the cells parallel to the sur- face of the epithelium was done with a micrometer eyepiece. It is essential that some method be employed which will result in representing all parts of a given circumference, and prevent undue choosing of certain types of cells that one comes to think of as typical. For example, one may take every cell in a given layer that has a nucleus and clearly defined boundaries, or every second or third cell of this description, according to the number of cells desired. The variation from cell to cell, in the same region, and from one part of the circumference to another, is very great. The largest cells may be six to ten times longer than the smallest. The first hundred cells in any given layer of a section, on the other hand, may be one and one-fourth times the size of the second hundred in the same section. But if the average of three hundred or more cells representing all parts of a given circumference is taken, and the measurements repeated in differ- ent sections from the same bladder, using the same method, the results will be nearly identical. So the method of taking every cell in a given layer, having a nucleus and clearly defined bound- aries, and comparing the average size with that of cells similarly chosen from another bladder is an entirely reliable method of comparison. In the ease of cells that have the shape of a parallel- ogram, the length of the side parallel to the surface of the epi- thelium is taken as the length of the cell. The results obtained from several measurements of each epi- thelium, and about six thousand cell measurements, in material from the six rabbits, were as follows (table 1): CHANGES IN BLADDER EPITHELIUM 143 TABLE 1 Bladder no. 1 (distended) MNCL OF GOINNA MUNA hektsaclie ee iwc sae Kb ove eee uns weds necvegh eg . 8 em. Length of cells: Average ARGEI BTCA ORI B VOM laters! s i cithe manne ati ¢ 98 cals wessinie a's = s 470 cells 51.4 Te MEE TE ee Ne on < ayers ahieBrasis vane tinance cide sans 385 cells 32.4y BLO MAUMEE TN sR riaeuilnsamn caine sa devcuancsslabvadscns 330 cells 18.84 Bladder no. 2 (completely contracted) Pets OPAUNO LITT. so ciersidelsiv a6 sine vob nidaiars sig ewiesw e's measurement impossible. Length of cells: ; LT SLATE Ley, Sia A RS es Ny ot One gS Ac eee re 386 cells 27.6u PMG ER mentite inet rics atta sks trite tes ad coos eas tae 275 cells 18.3p OLUMEVOR RA eet eset Ao ere So Acre Adee ns lene dacamael 220 cells 10.1p Bladder no. 3 (partially distended) Pent ty CHIU EMU ci. bie. cox cvie's wines hie oe a ditntdiacie tei nnsnnini asl ans ona sive aides 6.5 em. Length of cells: : PURI OLcr. Saaic's ates oe oss onda came e on pe aay deiees: Teak y 345 cells 46.2n PATEL ONE AAS (Se area oediand Putdiacs PaGaw Meteor creer ots cenkes 385 cells 29.9u BNC a he ct, gral & ida cctv davcaisich. o/s eects elelats & wis, \eisre. 0 330 cells 18.9 Bladder no. 4 (completely contracted) PTI ETAETEL OIGNGINUNS 7 cere sists vixsy oicm da we ciaumreitcs +s 0¢ measurement impossible. Length of cells: GEL EDers Lea amend thre «cides sik vin chien e dale aS ered s 220 cells 27.7 PIRCR LB ONS ce Berarse sek aviv JPsveh sist Vins Lae aes a «cite <8, cts 220 cells 18.8u BUR VOI ascot chet iia apelnicto, 5's, x, «fa.0 sie eee a ans cio d's 220 cells 9.64 Bladder no. 5 (contracted to beginning folding) PUNTO OPIUMANUNKe saat s,s as. > hiv5.s <\ > > 4,5 8S Reape oink Seyeele estates 40 cells 52.4u Sn ATL aistrsits\«, 7 p'n» ain tare oe hae eis eerie 440 cells 28.6 BTU LCR Fn 0c 0 1,550 fas ne oti emee am teaaale Sie = ximave ets 316 cells 22.4y Basal cells....... Bee aon. tnd od EON cP ERR Te 220 cells 12.5y Bladder no. 10 (distended) Tength or Sprnuouumns fo. i i. cscs ove Ghee eee ofecelcle ol pietva nie ae eceeteen 7.5 em, Length of cells: : ert eee s cao 0.» <:ns.si vpn degeedr eiaahe aeeanim meade ke 427 cells 67.3 ATCA CRE lars 0.sin's. 5 9007s. en ivth Bae a tian Sipe ele Te 330 cells 33.74 Br WAVER Se ac >. oo esos eae sane ean tp ene tne deen 330 cells 24. 7u BSBA ORION Ses e 2k vce. asleep: ce th mhieweknaies sahmieats 330 cells 14.4u A few ratios will suffice to point out the significance of these results (table 4): In comparing the completely distended bladder with the con- tracted and with the partly distended one, therefore, the ratios obtained for the cells diminish in value from surface to base as CHANGES IN BLADDER EPITHELIUM 147 they did in the previous series. Comparing them with the ratios for the epithelia, the only striking irregularity and by far the largest of its kind in either series, is found in the ratio of the first layer cells of bladders 10 and 8. Here the stretching of the cells far more than accounts for the stretching of the epithelium. Comparing bladder no. 9 with bladder no. 8, we find a similar divergence. This means, no doubt, that bladder no. 8 had unu- sually small surface cells, while bladders no. 9 and no. 10 were comparable. The ratios in the middle column are therefore the important ones. The ratios in this column, taken together, indi- cate that the number of layers was diminished by 7.4 per cent TABLE 4 RATIOS oF No. 10 No. 10 No.9 No.8 No.9 No.8 Lengths of epithelia................... 1.78 1.27 1.40 Lengths of cells: REMUS OL oe atctiskes tei aéikim clans mateicie & pics 2.31 1.28 1.80 PMIGUAGOR SG Se tu us etree tis cele oats 1.68 Leay 1.43 TO MAYOR aria) soe tide. BE tarsledieiwc ei shots 1.65 1.10 1.50 SBM COME te x alee tetes Hanns a.2.8 Sins 8c 1.48 1.15 1.28 during distention, while those in the previous series indicated a maximum of 12.5 per cent diminution. The possibility of cells ‘slipping by one another’ is therefore not eliminated. But it is evident that the decrease in layers, if present, is far less than the first glance at sections of contracted and distended bladders would suggest. Very slight tangency will increase the number of apparent layers when the cells are tall, as in contraction, whether the epithelium is folded or not. And this, with the thinness of the distended cells, accounts for the illusion. Just what is meant by ‘slipping by one another’ is seldom men- tioned. The only thing it could mean, so far as these studies sug- gest, may be shown by reference to figure 1. Beneath the only nucleus in the first layer is the junction of the two nucleated second-layer cells. If, on further distention, these two cells 148 OLIVER H. GAERBLER should lose their attachment to each other, the cell just beneath would touch the surface cell, and the number of layers be reduced by one. The two second-layer cells might still maintain their attachment to the surface cell and to the cell between and beneath them, so that the integrity of the epithelium would not be endangered. Both histological study and the ratios above given suggest that such occurrences are more possible in the lower layers than in the surface layers, for in the latter the appearance of the cells suggests that they are bound very firmly to their lateral neighbors. Some of the basal cells are so imbedded in the basement membrane that this perhaps determines their position quite as much as attachment to the neighboring cells. Turning again to figure 1, however, it is easy to see that a little more distention would cause the lower boundary of the nucleated surface cell, the connection between the second layer cells, and the upper boundary of the third layer cell to stain as one black line for a short distance. The interpretation of the microscopic picture would then become a matter of opinion. In the range of distentions above studied, which certainly equaled the range of normal physiological distention, there was little need for speculation, however, and the desired measurements could readily be made at a magnification of 950. It is interesting to note that during the measurement of the first 6000 cells, which brought under observation several times that number, only one mitotic figure was observed, and this was in the layer next above the basal layer. During the measure- ment of over 4000 cells in the second series several mitotic figures were observed, and surface cells with two, three, or four nuclei were more frequent than in the first series. Cuticular borders were not in evidence in these specimens, which were fixed in bichloride, and were in the final fixing solu- tion within ten minutes after the death of the animals. « CHANGES IN BLADDER EPITHELIUM 149 DISCUSSION London, in 1881, studied bladder epithelium in contraction and distention in connection with the problem of resorption. He used bladders from dogs, and tried at first to distend them im- mediately after removal by forcing the fixative into the interior. This method he abandoned, because the prepared specimens showed a torn epithelium that he attributed to hardening of the epithelium by the fixative while distention still continued. He therefore distended the bladders by surrounding them with a negative pressure while ureters were left open at atmospheric pressure, and filled and surrounded them with fixative after the desired distention had been reached. He also used the method of fixing bladders with urine left inside to avoid contraction, but left the urine in these bladders twenty-four hours. His principal conclusions were: 1) that the thickness of the epithelium and all the layers of the bladder wall increases with age and size of the animal, and perhaps also with developed habits of retaining urine, as in the case of house dogs; 2) that the volume of the epithelial cells, or the entire epithelium, is the same in distention as in contraction, or that the thickness of the epithelium varies in- versely as the area; 3) that the diminution of layers in distention is apparent, because of the diminution of layers of nuclei, but is not real if cell boundaries are taken into consideration. His clos- ing statement that the epithelium possesses greater elasticity dur- ing contraction than during distention is very peculiar, unless we regard the epithelium as active rather than passive in contract- tion and distention, and ascribe to the cells changing conditions of tone. London’s method of telling whether a section is tangent or not by noting whether the outline of the surface of the epi- thelium shifts on focusing is not infallible. The figures in this paper show that even the distended epithelium, when fixed, pos- sesses irregularities, such as bulgings over nuclei in the surface layer, and other elevations and depressions. If a section, per- pendicular to the general direction of the epithelial surface, in- cludes one of these irregularities, the outline of the surface will shift on focusing. And in bladders fixed in contraction 150 OLIVER H. GARBLER each cell bulges into the lumen, presenting a spherical surface, so that the free surface outline will shift on focusing, regardless of whether the section is tangent to the general direction of the epithelium or not. Whether the thin lines London describes and interprets as cell boundaries of cut edges of cells were the same as the boundaries of cells without nuclei shown in the above fig- ures is not certain. The above figures represent conditions in any one focal plane, and since the sections were 10. thick, the narrow edges of cells shown could be traced to wider portions on focusing, or, in the lower layers, to the nucleated portion of the cell. Dogiel (’90) studied the histology of the contracted bladder epithelium, especially of rodents, but also of dogs, cats, and man. He quotes Oberdieck as saying that in distention the surface cells flatten, while the deeper cells are displaced from their positions. He also cites Oberdieck’s statement that bladder epithelium, in general, may be considered as three-layered epithelium, and in his own work distinguishes four layers—a surface layer whose cells are thick platelets, and whose shape, seen in surface view is irregularly polygonal; a second layer of irregular cylindrical or cubical cells, with long axis perpendicular to the epithelial sur- face; a third layer of somewhat cylindrical cells, the end nearer the epithelial surface being club-like and the opposite end tapering and reaching the basement membrane; a fourth layer of round, oval, or fusiform cells occupying the spaces between the nar- rowed lower ends of the third-layer cells. He made extensive studies of cells in macerated specimens. The surface cells are said to consist of an outer homogeneous third, and a deeper granular two-thirds, containing the nucleus or nuclei. The outer homogeneous portion (cuticular border) separates on maceration, and is claimed to be of a mucoid nature. The granular appear- ance of the cytoplasm is attributed to fibrillar protoplasmic net- work. Dogiel further claims to have demonstrated, and figures an extensive system of interlocking of the cells of the first two layers of epithelium, by projections of the second-layer cells fitting into depressions of the lower surface of the surface cells, and says that through these interlockings protoplasmic fibrils extend from CHANGES IN BLADDER EPITHELIUM 151 one cell to another. On this basis he founds his conclusion that these first two layers of cells permit of no rearrangement what- ever and merely flatten in distention. This conclusion would be defensible only if an equally valid system of interlocking were demonstrated for the second-layer cells in their relations to one another, for, as shown in the discussion of the term ‘slipping by one another’ in connection with the cells of figure 1 above, it is shown that a cell need not lose all hold of its surroundings in order to part with the nearest neighbor in the same layer. The exist- ence of the large projections of the second-layer cells that fit into depressions in the bottom of the first-layer cells is questioned by other observers, who used mainly dog material. Dogiel empha- sized their prominence especially in material from small rodents, such as rats and mice. If they are sufficiently numerous in rab- bit bladders to be of essential importance, they should be seen more frequently in sections, since a 10u section takes in about half of a contracted second-layer cell. In the first series of blad- ders studied above, these projections were not seen at all. In the second series they were found occasionally. Wherever found, they were very definite structures. Whether fibrils extended from one cell to another could not be determined, because a definite cell boundary separated the cells. Dogiel describes these structures from macerated specimens. Harvey, in studying mac- erated preparations of bladder epithelium of dogs, did not cor- roborate these findings. He describes the cells as having a reg- ular outline, and finds no structures or projections similar to those ’ of Dogiel that could not be more readily considered products of maceration. Eggeling ('01) studied the histology of the surface layer of bladder and ureter and reviewed the literature on the subject. He notes the recorded variability of a cuticular border in ureters from different animals and with various fixatives, which showed gradations from practieal absence to virtual cornification of the entire surface layer. A description of the cuticular border, as demonstrated after aleohol-chloroform-acetic-acid fixation fol- lows, and its significance in protecting the epithelium from con- tact with urine and in preventing or reducing resorption is dis- 152 OLIVER H. GAEBLER cussed. The existence of canals in the epithelium, described by Lendorf, is not corroborated, and the evidence of secretory activity of the surface cells is considered doubtful. To each of these articles a large bibliography is appended, but the subjects treated deal mainly with the histology for any static condition—studies on channels in epithelia, studies on goblet cells, ete.—and do not relate to distention. Harvey, in 1909, published an interesting article on variations in the wall of the bladder and ureter in contraction and disten- tion. He used dogs, and distended the excised bladders by fore- ing in Zenker’s fluid. Staining was done with hematoxylin and congo-red. Cell boundaries are described as distinct only in the contracted bladder and in the surface layer of the distended. In the other layers of the distended bladder they are ‘‘discontinu- ous or in fragments, as though the cytoplasm of adjacent cells had fused in places, or distention has made the membranes so thin as to be invisible.’ The nuclei are depended upon in this inquiry into the relations that cells assume in contraction and dis- tention, as in the earlier work of Herzog. In regard to bladder epithelium, the following conclusions are reached 1) that the distended epithelium is one-sixth the thickness of the contracted; 2) that the number of layers of nuclei is decreased 50 per cent, approximately, in distention; 3) that there may be, in addition to the stretching of cells, a slight displacement of the cells from their relative position, hence, an actual diminution of the number of layers. The diminution in the number of layers of nuclei is interesting. The first conclusion above tabulated, together with the work of London, which showed that the volume of the epithelium in dis- tention is the same as that in contraction, show that the surface of the epithelium distended by Harvey increased six times. A line perpendicular to the epithelium at any point would have a sixth as many chances of piercing nuclei in the distended bladder as it would have in the contracted. And a plane, passing entirely through the contracted and distended bladders at comparable points would have 2.4—the square root of six—times the number of chances of encountering nuclei in the contracted bladder that CHANGES IN BLADDER EPITHELIUM 153 it would have in the distended, if the nuclei remained unchanged in size. But they do not. Measurement of 110 nuclei of con- tracted bladder no. 6 of the above series, and 110 nuclei of the distended bladder no. 1 showed that while the epithelium had been stretched along the equator to 2.1 times its former length, the nuclei had been stretched to 1.14 times their former diameter parallel with this direction. If a stretching of 2.1 times increased the diameter by 0.14, a stretching of 2.44, as in Harvey’s work, would probably increase it to 1.16 times its former length. This would counteract the effect of increasing distances between the centers of nuclei, so that a plane having a chance of passing through 244 nuclei in the contracted bladder would pass through 116 in the distended. ‘This amounts to a 52.4 per cent decrease, or very nearly the percentage decrease established by Harvey in counting the layers of nuclei in a given focal plane. SUMMARY The results of this investigation, so far as the principal problem stated at the beginning is concerned, may be summarized as follows: 1. Moderate physiological distention of the rabbit’s bladder is reached without any evidence that the cells of the epithelium - are displaced from their relative positions, that is, without any decrease in the number of layers. 2. Very great physiological distention of the rabbit’s bladder probably results in a slight decrease in the average number of layers. This decrease is scarcely demonstrable without making cell measurements, and these show that it does not amount to more than 12.5 per cent. 3. Histological evidence and measurements confirm ths idea that the cells of the epithelium are bound to one another more firmly in the first and second layer than in the third or deeper layers. It is obvious that the conclusive data cover only the range of distention and contraction that lies between beginning folding of the epithelium and maximum physiological distention. Whether the cells form more layers in complete contraction is not known. 154 OLIVER H. GAEBLER All that is shown is that they do not contract further after folds have begun to form. In conclusion, I wish to acknowledge my indebtedness to Dr. E. R. Clark, under whose direction this investigation was carried — out. BIBLIOGRAPHY Doaier, A. S. 1890 Zur Frage iiber das Epithel der Harnblase. Archiv fiir microscopische Anatomie, Bd. 35, 8S. 389-407. Eaoceuine, H. 1901-02 Ueber die Deckzellen im Epithel von Ureter und Harn- blase. Anat. Anzeiger, Bd. 20, S. 116-123. Harvey, R. W. 1909 Variations with distention in the wall and epithelium of the bladder and ureter. Anat. Rec., vol. 3, pp. 296-307. Lewis AND StéHr 1913 A textbook of histology. Blakiston’s, Philadelphia, second edition, p. 324. Leg, A. B. 1913 Microtomist’s vade mecum, seventh edition. P. Blakiston’s ‘Sons & Co., Philadelphia. Lonvon, B. 1881 Das Blasenepithel bei verschiedenen Fiillungszustiinden der Blase. Arch. fiir Physiol., 8. 317. Matiory anp Wricur 1913 Pathological technique, fifth edition. W. B. Saunders & Co., Philadelphia. =——- Cog fll Be atl gli wf oy Seees pepe pine sae oti Hs in | as Resumen por el autor, W. N. Hess, Cornell University, Ithaca. Trdqueas en los 6rganos luminosos de algunos Lampiridos comunes. Comparando los principales troncos traqueales y sus rami- ficaciones mas importantes en los segmentos abdominales de algunos de nuestros mas comunes lampiridos, el autor ha encon- trado que la disposicién de estas ramificaciones es semejante en cada segmento abdominal excepto en el noveno, y que no existen nuevas ramificaciones en adicién a los principales troncos tra- queales. La principal diferencia consiste en el excesivo tamaiio de los troncos principales y sus ramificaciones en los segmentos en que estan colocados los 6rganos luminosos. Aun cuando no nacen nuevas ramificaciones en los troncos principales, las que existen son mas gruesas y parecen dividirse mucho mas frecuente- mente en ramillas mas y mas finas, que las que existen en otros segmentos abdominales, con el fin de aportar mayor cantidad de aire a los 6rganos luminosos. En los machos de nuestros lampfridos mas luminosos algunos de los conectivos longitudinales de las tréqueas situadas en los segmentos que contienen los 6rganos productores de luz, en vez de unir entre si los troncos traqueales de estos segmentos, se han dividido y ramificado considerablemente, conduciendo directamente el aire a los 6rganos luminosos. Translation by José F. Nonidez Cornell Medical College, New York AUTHOR'S ABSTRACT OF THIS PAPER ISSUED . BY THE BIBLIOGRAPHIC SERVICE, NOVEMBER 15 TRACHEATION OF THE LIGHT-ORGANS OF SOME : COMMON LAMPYRIDAE! WALTER N. HESS TEN FIGURES The light-organs of all the luminous fireflies that have been described occupy a part, or the entire ventral portion, of one or more abdominal segments. In a large per cent of luminous males the organs occupy the entire ventral portions of the sixth and seventh abdominal segments, while not infrequently the organs of the females are much smaller and restricted to a small area in the sixth segment. In our luminous larvae the organs are usually paired and lie in the ventro-lateral portion of the eighth abdominal segment. The structure of the light-organs in all insects that have been studied, whether in the larva, pupa, or adult, appears to be very similar. They have always been found to consist of an inner, non-photogenic layer called the reflector and an outer luminous, or photogenic, layer (figs. | and 2). The author is indebted to Dr. William A. Riley, under whose direction this study was made, for his helpful suggestions and criticisms. Numerous workers have studied the structure of the mature light-organs, and in this connection many have figured the arrangement of the tracheal end-cells within the organ itself. Yet so far as any detailed study of the arrangement of the main tracheal trunks and branches that supply the light-organs is concerned, nothing seems to have been done except a brief work by Geipel (715). He figured, in a semidiagrammatic way, their arrangement in the male of Luciola africana. According to his ‘Contribution from the Entomological Laboratory of Cornell University. 155 156 WALTER N. HESS Fig. 1 Photinus scintillans, male, diagrammatic drawing to represent the two layers of fhe light-organ and the general arrangement of the larger trachea. A, ampulla; D 7, dorsal tracheal trunk; P, photogenic layer; R, reflector layer; S, spiracle; V 7, ventral tracheal trunk. Fig. 2. Photurus pennsylvanica, larva, diagrammatic drawing to show the two layers of the light-organ, and the arrangement of the trachea. A, ampulla; D T, dorsal tracheal trunk; P, photogenic layer; 2, reflector layer; S, spiracle; V T, ventral tracheal trunk. Fig. 3 Photurus pennsylvanica, larva, ventral view of abdomen. The dark elliptical areas which are located on the eighth abdominal segment represent the larval light-organs, L O. Fig. 4 Photurus pennsylvaniea, larva, dorsal view of the principal trachea of the seventh and eighth abdominal ‘segments. A, ampulla; D, dorsal longi- tudinal tracheal connective; D T, dorsal tracheal trunk; L O 7, light-organ tra- chea; S, spiracle; V, ventral longitudinal tracheal connective. All tracheae shown with small branches supply the light-organ. TRACHEATION OF LIGHT-ORGANS-——LAMPYRIDAE 157 description, the main tracheal branches arise irregularly from the ventral transverse tracheal connectives. In order better to understand the general relation of the tra- cheal trunks and their branches which supply oxygen to the light- organs of the adult and larva, a diagrammatic drawing was made of a cross-section through the seventh segment of a male of Photinus scintillans (fig. 1), and through the eighth abdominal segment of the larva of Photurus pennsylvanica (fig. 2). Both figures readily show the dorsal and ventral tracheal trunks which separate from the ampulla near the spiracle. In the case of the adult, the ventral trunk gives off numerous branches, which soon divide, sending their little tubes into the light-organ. These tubes pass through the reflector layer into the photogenic layer where they end in numerous tracheoles. The light-organs of the larva, however, are each supplied by one large tracheal branch, which leaves the ventral trunk near the ampulla. As it enters the light-organ it divides profusely, sending its branches throughout the region of the photogenic layer (P). In the larva of Photurus pennsylvanica (fig. 3, LZ O) the light- organs appear externally as two small oval areas on the ventro- lateral sides of the eighth abdominal segment. Since it was found that the arrangement of all the main tracheal branches in the different abdominal segments of the larva, except the ninth, are similar to those shown in the seventh and eighth segments (fig. 4), the trachea of only these two segments were figured. As can be readily seen by a comparison of the tra- cheation in these two abdominal segments, the branches arising from the transverse trunk in each segment are similar and they are bilaterally arranged. The trachea which supply oxygen to the light-organs in segment eight are simply enlarged branches which arise from the ventral transverse tracheal connective (V 7) and correspond to similar branches which arise from the ventral transverse tracheal connective in segment seven. The branch from the ventral tracheal trunk in segment eight which supplies the light-organ (ZO T) is shown with many of its branches. The adult female of Photurus pennsylvanica, which is one of our largest native luminous fireflies, has the light-organs restricted Vig. 5 Photorus pennsylvanica, female, ventral view of abdomen. The stip- pled areas on the sixth and seventh abdominal segments represent the adult light-organ (A O). Fig. 6 Photurus pennsylvanica, female, dorsal view of the principal trachea of the fifth, sixth, and seventh abdominal segments. For labels see figure 4. Fig. 7 Photinus scintillans, male, ventral view of abdomen. The stippled areas on the sixth and seventh abdominal segments represent the adult light- organ (A O). : Fig. 8 Photinus scintillans, male, dorsal view of the principal trachea of the fifth, sixth, and seventh abdominal segments. For labels see figure 4. Fig. 9 Photinus scintillans, female, ventral view of abdomen. The shaded area on the sixth abdominal segment represents the adult light-organ (A QO). Fig. 10 Photinus scintillans, female, dorsal view of principal trachea of the fifth, sixth, and seventh abdominal segments. For labels see figure 4. 158 TRACHEATION OF LIGHT-ORGANS—LAMPYRIDAE 159 to an area covering about two-thirds of the sternites of the sixth and seventh abdominal segments (fig. 5, A O). These organs are supplied with branches that arise from the ventral transverse tracheal connectives of the sixth and seventh abdominal seg- ments, which are shown with their many branches (fig. 6). The arrangement of the tracheal branches in both segments is the same, and these branches correspond to similar trunks found in segment five, as well as to those in the other anterior abdominal segments. These trunks are much smaller than they are in the male, due to the fact that the organs are smaller, and hence they do not require as large an air supply. The tracheation of the light-organs of the male Photurus pennsylvanica was not figured, as it was found to be similar to that of the male of Photinus scintillans, which will be discussed. The adult male of Photinus scintillans, like most of our other luminous males, has its light-organs extensively developed so that they cover the entire sternites of the sixth and seventh abdominal segments (fig. 7, A O). The main tracheal trunks of this insect in the sixth and seventh abdominal segments were found to be of immense size (fig. 8), in order to supply the large amount of air that is needed by these light-organs. A brief description of these enlarged trunks will readily show the extreme of tracheal specialization for the supply of air to the light-organs of fireflies. The arrangement of the tracheal branches which arise from the ventral transverse tracheal connective of segment . six is practically identical with the arrangement of the branches which arise from the corresponding trunk in segment five. The chief difference is that they are larger and the finer branches appear much more numerous. The arrangement of the branches in the sixth abdominal segment correspond very closely to those in the seventh abdominal segment. The longitudinal tracheal connectives between these two segments have a tendency to become modified into branches which supply the tissues of the light-organs, but no new branches were found to arise from the transverse tracheal connective of either segment. In the speci- men that was figured the ventral longitudinal tracheal connective (V). between segments six and seven, on the left side, is not 160 WALTER N. HESS continuous, but has divided near the middle, and has become much branched for the purpose of supplying air to the light- organs. On the right side this connective, in the specimen which was drawn, was found to be very narrow, and at one point it showed evidence of a tendency to divide. The ventral transverse tracheal connectives in segments six and seven are very large from the spiracles to the center of the body. Here they become the same size as corresponding trachea in the other abdominal segments. In no case are accessory branches found to arise from the ventral transverse tracheal connectives, but the branches frequently divided and subdivided into numerous smaller branches, as soon as, or soon after, they arose from the main transverse trunks. A small amount of air for the light-organs evidently enters the spiracles of the fifth and eighth abdominal segments as certain of the longitudinal tracheal connectives leading from these segments to those of the light-organs are larger than in the other segments. The female of Photinus scintillans, which has a very small light-organ in the sixth abdominal segment (fig. 9, A O) naturally has a reduced air supply. The main tracheal trunks of the sixth abdominal segment are somewhat enlarged (fig. 10), but they are small in comparison with the corresponding trunks in the male. As is also true of the other fireflies studied, no new tracheal branches are found to arise from the ventral transverse tracheal connectives, but these branches divide into numerous smaller branches in the region of the light-organs, for the purpose of supplying, with a large amount of air, the tissues of this structure. By a comparison of the main tracheal trunks and their princi- pal branches in the abdominal segments of some of our common luminous fireflies, it was found that the arrangement of these branches was similar in each abdominal segment except the ninth, and that no new branches were added. The chief difference was found in the excessive size of the main tracheal trunks and their branches in the segments where the light-organs were located. While no new branches arose from the main tracheal trunks, those present appeared to divide much more profusely into finer and TRACHEATION OF LIGHT-ORGANS—LAMPYRIDAE 161 finer branches than the corresponding trunks in the other abdomi- nal segments, for the purpose of supplying a large amount of air to the light-organs. In the male fireflies of our most luminous species some of the longitudinal tracheal connectives in the segments containing the light-organs were not found connecting the tracheal trunks of these segments, but instead they were greatly branched supplying air directly to the light-organs. a Ee Gieties ee ee Cyr heavens couvels gtlye") 17 «i AR eer ees: aes ai 8S se AOL © WOT. a, tan 4 eee * @a meus ha ~> viv de eo emotes swrdalyel mm a w/e lead Peepers) « vy . bein bie jt ae > Repeat ioe 4A ee Oe) CER ene va wget e, 16g Gee sy togiies oon : Lo 7 ht . e ? a a == oP ad rt ‘st eats : i 7 ee ¢ * 2p = » os 4 7 ee _ Yo u a. we - af o(> OF rR) spf Dev, Fi = e@ iy Bs ~ ee « gi< . 7 ia © a © 7) bo eS ’ aie a . - oe As , 4 a * r a - . 4 ogy, - by rs a= i 1 : = * ied 7a =A =< - @ — . = ?_ hon age ae - : 7 . “a ss : 7 : a VPA ree te ‘ — <)> ie . : 2 . PROCEEDINGS OF THE AMERICAN SOCIETY OF ZOOLOGISTS EIGHTEENTH ANNUAL MEETING The American Society of Zodlogists held its Eighteenth Annual Meeting at the University of Chicago in conjunction with Sec- tion F. of the American Association for the Advancement of Science and in association with other biological societies, Decem- ber 28, 29 and 30, 1920. The officers for the year were: President: Gilman A. Drew. Vice-President: Caswell Grave. Secretary-Treasurer: W. C. Allee. Local Committee: H. H. Newman, Chairman, C. R. Moore and A. W. Bellamy. Executive Committee: R. P. Bigelow, H. V. Wilson, M. M. Metcalf, George Lefevre and C, M. Child. In the absence of the Secretary, H. V. Neal was elected Sec- retary pro lem. BUSINESS TRANSACTED The principal business session was held Thursday morning, December 30. The business was completed at an asjounned session held at noon of the same day. Business from the Advisory Board The Advisory Board authorized in 1919 and organized as follows: To serve one year, V. E. Shelford and C. C. Nutting; to serve two years, J. T. Patterson and Robert Chambers, Jr.; to serve three years, M. M. Metcalf and G. N. Calkins; to serve four years, W. E. Castle and F. R. Lillie (Chairman), recom- mended approval of a continuation of conferences between the Secretaries of the various Biological Societies. The board also recommended approval of the following memo- randum from the Ecological Society of America: 163 164 AMERICAN SOCIETY OF ZOOLOGISTS Report on the Preservation of Wild Life The Ecological Society of America’s committee on the preservation of natural conditions, while unable to deal with problems concerning wild life not in reserves, continually encounters the fact that individual species are menaced with extine- tion by agricultural encroachments. Two of these menaces are: 1. Clean-culture (roadside mowing and burning) as distinguished from road- side and streamside shrubbery and bird and original life preservation. Birds are decreasing for lack of nesting sites, on account of destruction of breeding conditions. Entomologists and some agriculturists maintain that this condition is necessary to agriculture. Bird men insist that birds are also essen- tial. It is known that a few states encourage roadside shrubbery while several require roadside mowing. The practice in the various parts of the United States and Canada should be ascertained. The effect of different procedures should be determined. The areas in which specially destructive and drastic measures such as burning for insect pests are necessary should be clearly defined and limited and the public informed as to the dangers of such burning. 2. Upland marshes are important as sponges storing water and letting it out slowly during dry seasons, thus controlling floods. Such marshes are gradually being drained and the flood menace is increasing every year. The only way to save these natural resources and at the same time, the swamp faunas, especially the birds, is to utilize the swamps for agriculture. To this end several water-culture experiment stations should be established. For the present there should be one, perhaps at Cornell University, to deal with the upland marsh problems. There should be another in connection with Okefinokee swamp and one in connection with the coastal swamps of New Jersey. In addi- tion to frogs, fish, and birds, a number of plants are good for food, etc.; e.g., cattail flour and cattail paper have recently been tried with success. Swamp potatoes, the corms of arrowhead, and seeds, roots, and stalks of our native lotus served as food for the American aborigines and pioneers. Hedrick (Sci- ence, 40: 611), Claussen (Sci. Mo., 9: 179), and Needham and Lloyd (Life of Inland Waters) have discussed these questions and suggested or advocated the improvement and culture of aquatic plants. : It is the belief of the committee that all organizations in any way interested should combine efforts for the investigation of these questions. V. E. SHetrorp, University of Illinois, Chairman. The Society unanimously approved both recommendations. Business from the Executive Committee The following change in the Constitution having been approved and published as required by Article VI was unanimously passed: PROCEEDINGS 165 Article II, add Section 4. Foreign Zodlogists, not members of this Society, may be elected Honorary Fellows upon unanimous recommendation of the Executive Committee by a majority vote of the members present at any meeting of the Society. Honorary Fellows shall not be required to pay dues. By-Law 5 was ordered amended to read: It shall be the policy of the Society to hold its annual meetings in both Eastern and Central territory and the distribution of meetings between the two terri- tories shall be determined in general on the basis of the representation of Eastern and Western members in the Society. The Constitution and By-Laws as amended will be found on pages 233-236 of this Journal. Election of Members The Executive Committee recommended the following persons for election to membership in the Society: 1. CuapmMan, Roya N., B.A., M.A. (Minnesota), Ph.D. (Cornell), Assistant Professor of Animal Biology; Assistant Entomologist, Experiment Station, University of Minnesota, Division of Entomology, University Farm, St. Paul, Minn. 2. Dawson, James Artuur, A.B. (Dalhousie), A. M., Ph.D. (Yale), Professor of Biology, Dalhousie University, Halifax, Nova Scotia, Canada, 3. Dunn, Lestiz Crarence, 8.B. (Dartmouth), 8.M., Sc.D. (Harvard), Poultry Biologist, Connecticut Agricultural Experiment Station, Storrs, Conn. 4. Duporte, Ernest MebvVILLE, M.Sc., B.S.A. (McGill), Instructor in Zodlogy and Entomology, Macdonald College, Macdonald College P. O., Province Quebec, Canada. 5. Fraser, Caoartes McLean, A.B., A.M. (Toronto), Ph.D. (Iowa), Professor of Zodlogy, University of British Columbia and Director of Marine Bio- logical Station, Nanaimo, University of B. C., Vancouver, B. C., or Biological Station, Nanaimo, B.C, 6. Gotpsmitra, Witu1aAmM Marion, B.Pd., A.B., A.M., Ph.D. (Indiana), Pro- fessor of Biology, Southwestern College, Winfield, Kansas. 7. Grier, Norman McDowe tt, 8S. B., A.M., Ph.D. (Pittsburgh), Professor of Biology, Washington and Jefferson College, Washington, Pa. 8. Hecut, Seria, Ph.D. (Harvard), Assistant Professor of Physiology, Creighton Medical College, Omaha, Neb. 9. Hess, Watter N., A.B. (Oberlin), A.M., Ph.D. (Cornell), Professor of Biology, De Pauw University, Greencastle, Indiana. 10. Jewett, Minna E., A.B. (Colorado College), A.M., Ph.D. (Illinois), Assis- tant Professor of Zodélogy, Milwaukee-Downer College, Milwaukee, Wisconsin. 166 AMERICAN SOCIETY OF ZOGLOGISTS _ 11. Jos, Tuesue T., A.B., A.M., Ph.D., Associate Professor of Anatomy, Loyola University School of Medicine, 706 S. Lincoln St., Chicago, Ill. 12. Kupo, Roxusasuro, D.Ag.Se. (Tokio), Instructor in Zoédlogy, University of Illinois, Urbana, Illinois. 13. Linu, RatpaS., A.B. (Toronto), Ph.D. (Chicago), Bidlogist, Nela Research Laboratories, Department of Pure Science, Nela Research Laboratories, Nela Park, Cleveland, Ohio. : 14. Lippincorr, Witi1am Apams, A.B. (Illinois College), S.B. (Iowa State), S.M., Ph.D. (Wisconsin), Professor of Poultry Husbandry and Poultry Husbandman, Kansas State Agriculture College, Manhattan, Kansas. 15. McCuttocu, IRENE, Ph.D. (California), Professor of Biology, Sophie New- comb College, New Orleans, La. 16. May, Henry G., S.B. (Rochester), Ph.D. (Illinois), Professor of Bacteriology Rhode Island State College and Chief, Division of Animal Breeding and Pathology, Agr. Exp. Station, Kingston, R. I. 17. Murrxowsk1, Ricuarp Antuony, A.B., A.M., Ph.D. (Wisconsin), Assistant Professor of Zoédlogy and Entomology, University of Idaho, Moscow, Idaho. 18. Oumstep, J. M. D., Ph.D. (Harvard), Instructor in Physiology, Toronto University, Toronto, Canada. 19. Snyper, Tuomas Exviorr, A.B. (Columbia), M.F. (Yale), Ph.D. (George Washington), Specialist in Forest Entomology, Bureau of Entomology, U.S. Department of Agriculture, Washington, D. C. 20. Swineie, Witpur Wiis, A.B., A.M. (Kansas), Ph.D. (Princeton), Instrue- tor in Biology, Sheffield Scientific School, Yale University, Osborn Zodlogi- cal Laboratory, New Haven, Conn. 21. TayLtor, Cuarues Vincent, Ph.D. (California), Assistant Professor of Zoél- ogy, University of California, East Hall, University of California, Berkeley, Calif. 22. Turner, CLARENCE Lester, A.B., A.M. (Ohio Wesleyan), Ph.D. (Wisconsin), Professor of Zoélogy, Beloit College, Beloit, Wisconsin, 23. Weese, AsA Orrin, A.B. (Minnesota), A.M. (Illinois), Professor of Biology, University of New Mexico, Secretary, Ecological Society of America, Albuquerque, N. Mex. These nominees were unanimously elected. The Journal of Morphology The Committee on Publication appointed at St. Louis sub- mitted the report given below to the Executive Committee. Acting by the authority given it at St. Louis, the Executive Committee approved the action of the Committee and the report gives the basis for the codperation between the Society and The Wistar Institute in publishing the Journal of Morphology. PROCEEDINGS 167 Tue Wistar INSTITUTE OF ANATOMY AND BIOLOGY Philadelphia, Pa. April 5th, 1920. Dear Dr. Metcalf: In order to make perfectly clear the relation of the American Society of Zoologists to The Wistar Institute and the Journal of Morphology, I wish to confirm the impression that you have that the Society is to elect the Managing Editor and Associate Editors of the Journal of Morphology, and to make such arrangements as may seem desirable for the scientific control of this journal. Yours very truly, (Signed) M. J. Greenman. Dr. M. M. Metcalf Philadelphia, Pa. To the Executive Committee of The American Society of Zoologists: Sirs:—In accordance with your instructions, your Committee, consisting of W. E. Castle, Caswell Grave and Maynard M. Metcalf, ‘“‘appointed — (1) to initiate a scientific policy concerning the Journal of Morphology; (2) to nominate an Editorial Board; (3) to consult with the Advisory Board of The Wistar Institute concerning both the proposed policy and the editorial nominations; (4) to refer the recommendations for final action to the Executive Committee in 1920 and thereafter through the Executive Committee to the Society at its annual meeting,’’ first consulted with each other by correspondence and in person, and afterward met with the Advisory Board of The Wistar Institute at its annual meeting, April 4th to 6th, in Philadelphia. There was full and frank discussion at this meeting of the matters involved. Your Committee being unanimous in its desire to nominate Prof. C. E. McClung to be Managing Editor of the Journal of Morphology, and having learned that such nomination would be particularly pleasing to the Director of The Wistar Institute and its Board of Advisors, obtained Prof. MeClung’s consent to the nomination and then asked him to meet with us in consultation upon the other items submitted to us for recommendation. Dr. Greenman, Director of The Wistar Institute, was also further consulted in regard to all the matters mentioned in this report and there has been com- plete agreement of your Committee and of Prof. McClung and Dr. Greenman in the following recommendations: I. That there be elected a Managing Editor of the Journal of Morphology to serve for a period of five years and that he be eligible to reelection at the expira- tion of his period of service. Your Committee feels that there is no objection to long tenure of the office of Managing Editor of the Journal and that this is desirable. II. That there be elected nine Associate Editors of the Journal of Morphology, three to serve until January Ist, 1922; three to serve until January Ist, 1923; and three to serve until January Ist, 1924. That beginning with the annual meeting of the Society at the end of the year, 1921, and annually thereafter, there be elected by the Society upon nomination by the same method as is provided for the nomination of other officers, three Asso- ciate Editors to serve for three years to take the places of the three retiring Asso- 168° AMERICAN SOCIETY OF ZOOLOGISTS ciate Editors. That before making nomination of such Associate Editors, the Nominating Committee shall consult the Board of Editors of the Journal of Morphology and also the Director of The Wistar Institute and through him the Board of Advisors of this Institute. This is suggested as a courtesy to the Institute, not as a matter of necessity, for the final authority for the election of the Editors of this Journal will lie with the Society. That a retiring Associate Editor shall not be eligible to fedlochiae until after the expiration of one year subsequent to his retirement. III. That the three Associate Editors elected to serve until January 1st, 1924, be constituted for the year 1921 a consuJting committee to visit The Wistar Insti- tute upon its invitation and at its expense, to familiarize themselves with the work of the Institute and to take from the Society to the Institute and receive from the Institute for the Society, suggestions as to the relations between the Society and the Institute and as to opportunities for coéperation not only in matters of publication, but in other matters as well in which the codperation of the Institute and the Society may promote the interests of Zodélogy. The Institute has suggested the election of such a Committee and has urged that the Society through this Committee make with freedom and frankness suggestions that may enhance the usefulness of the Society and of the Institute in their commen service to Zodlogical science. The Society should, in this connection, realize the policy of the Institute to limit for the present the field of its activity with a view to greater see through concentration of effort. The Institute further desires from year to year, such a Consulting Committee in order that there may soon come to be in the Society a considerable number of its members who shall understand the purposes, plans and methods of opera- tion of the Institute with a view to most effective codperation between the two organizations. Your present Committee recommend that this Consulting Committee be the three Associate Editors elected to serve for three years, so that they may have opportunity to enter upon their service as Editors with fuller understanding of the institution with which they will be coéperating in their editorial duties. We further recommend that a similar Committee be appointed for the year 1922, and annually for each year thereafter and that this Committee consist annually of the three newly elected Associate Editors. Your Committee desires to express its sense of the great value of such mutual understanding of the Society and the Institute of one another’s spirit, purposes plans and methods, this sense being based upon our own informing and delightful experience as guests of the Institute for these two days. IV. That the Board of Editors make annual report to the Society upon the Journal of Morphology and any matters of publication that they may wish to include. V. That the Consulting Committee or any of its members, if they desire to do so, may report any year to the Society any suggestions or recommendations growing out of their visit to and consultations with The Wistar Institute. VI. That Prof. C. E. McClung be elected Managing Editor of the Journal of Morphology. PROCEEDINGS 169 age That Associate Editors of the Journal of Mephoy be elected as follows: . To serve until January Ist, 1922 Prof. Gary N. Calkins Prof. J. S. Kingsley Prof. Wm. Patton 2. To serve until January Ist, 1923 Prof. E. G. Conklin Prof. M. F. Guyer Prof. W. M. Wheeler 3. To serve until January Ist, 1924 Prof. C. A. Kofoid Prof. F. R. Lillie Prof. J. T. Patterson VIII. That matters of Editorial Policy and method, not covered by the pres- ent report, be left to the Board of Editors composed of the Managing Editor and the Associate Editors, subject, of course, to any action by the Society. It may be well to state that no fundamental changes in the character or con- duct of the Journal of Morphology is contemplated and that it is planned to con- tinue publishing in the Anatomical Record the Proceedings of the Society. IX. That your present Committee be discharged at such time as you shall have received and have acted upon this our report. Your Committee cannot refrain from expressing its deep sense of the gener- osity and the fine spirit of coéperation shown by The Wistar Institute. They are giving to our Society the unrestricted management and use of the Journal of Morphology which is owned by the Institute. Their only desire clearly is to increase their own efficiency and the effectiveness of the Society of Zodlogists in promoting biological research through coédperation. They not only wish to establish at once codperation in publication, but they invite suggestion from time to time as to codperation in other ways; the relation they suggest between the two organizations is as unique as it is generous and your Committee believes that it is another instance of statesman-like vision such as is shown in the Insti- tute’s plan, already realized, to distribute its publications more widely than any scientific serial publications have heretofore been distributed. The only worthy thanks we can suggest from the Society to the Institute lie in accepting the proffer of coéperation and joining our efforts in effective service to zoélogical research. We append to this report a letter from Dr. Greenman which makes clear the generous confidence of The Wistar Institute in the Society of Zodlogists. Philadelphia, Pa. (Signed) W. E. Casrie, April 5th, 1920. CasWELL GRAVE, : Maynarp M. Mercatr. C. E. McClung reported to the Society concerning the present status of the Journal of Morphology and on motion by Dr. Me- Clung the Society recommended that the subscription price of the Journal of Morphology be increased from $9.00 to $12.00 per volume. 170 AMERICAN SOCIETY OF ZOOLOGISTS Report of the Secretary During the year 1920, two members of the Society have been removed by death, E. L. Michael and George D. Allen; three have resigned and six members have been dropped for non payment of dues, leaving at present, before the election of new members, 305 members of the Society. During the year, the American Association for the Advance- ment of Science, recognizing the high standard of the American Society of Zodlogists in choosing their membership, agreed to recognize election to membership in the Society as a certification of eligibility to being enrolled as a Fellow in the Association. In the future, all members elected will be immediately nominated as Fellows in the Association. The Secretary called the attention of members who enter nomi- nations or membership that it is very important that a complete list of the nominees’ publications be filed with page references and in addition that a short biographical sketch be furnished similar to that found in American Men of Science. The report was ordered to be placed on file. Treasurer’s report for 1920. Receipls to December 24, 1920 Balance on handiaplast report... 30. fst oe wee eee ees Sd ela $1,204.30 OS: NS5200\dilenereeser. s5...0. Konded. Sasdee ade eee $340.00 2016700! diesen fees facil. 2-0 RR ee ee 1,407.00 V7 11.50 ditester ee ...!a:5 << .\otha din arate ata anis tee anit 195.50 6 irregular sums from members............... 000005 23.30 Refund from Wistar Institute .. 2... fie avasideelebies ve clan 13.50 Credit ‘at Wastarsustitute. .. oi... wesswe sekaccttot ese pan 2.00 Interest on Savings deposits. ..............0 cee esceeeceee 43.69 Uncorrected error by bank clerk...............+..0.000000- 10.00 2,034.99 POUR SECON MNEEE iis 5.0.04 A ary oy : * a a “ A “@ asi te _ ™ . P = . ay > 5 7 | aa) rs ar =~ ‘a = . a | 4 s —. } 4 a hii 7 é&2 < : | Agar] oe Sl) oS i 9 baw s Wp ~4> - e753 ¢ or fe) ee , y vi i ove ae ae 4 mn, 01) RAAT | Are ee oan ’ j aw ; Yitvee Oe ag hake (P Gi-ps txc ol Debheegié” ¢ seis md - alt, 4.9 * yl - 9 Pe en » | “a i ae v , .. gid oe ~ cm 7° ot a er tT be " o4 » mis ‘ire oo . an aa. oe 7 fr . it % ‘ . ea pth ra 72) rare sy 2 _ ee ad be . Pas . bd oe LES ‘ 12 ob. eadh —@ * ~ ~ o 9 A AMERICAN SOCIETY OF ZOOLOGISTS CONSTITUTION, OFFICERS AND LIST OF MEMBERS OF THE SOCIETY CONSTITUTION ARTICLE | NAME AND OBJECT Section 1. The Society shall be called the ‘‘American Society of Zodlogists.’’ Sec. 2. The object of the Society shall be the association of workers in the field of Zodlogy for the presentation and discussion of new or important facts ‘and problems in that science and for the adoption of such measures as shall tend to the advancement of zodlogical investigation in this country. Articie II MEMBERSHIP Section 1. Members of the Society shall be elected from persons who are ac- tive workers in the field of Zodlogy and who have contributed to the advancement of that science. Sec. 2. Election to membership in the Society shall be upon recommendation of the Executive Committee. Sec. 3. Each member shall pay to the Treasurer an annual assessment as determined by the Society. This assessment shall be considered due at the annual meeting and the name of any member two years in arrears for annual assessments shall be erased from the list of members of the Society, and no such person shall be restored to membership unless his arrearages shall have been paid or he shall have been re-elected. Sec. 4. Foreign Zodlogists, not members of this Society, may be elected Honorary Fellows upon unanimous recommendation of the Executive Committee by a majority vote of the members present at any meeting of the Society. Honor- ary Fellows shall not be required to pay dues. Articie III OFFICERS Section 1. The officers of the Society shall be a President, a Vice-President a Secretary-Treasurer and the members at large of the Executive Committee. Sec. 2. The Executive Committee shall consist of the President, the Vice President, the Secretary-Treasurer and five members elected from the Society at large. Of these five members, one shall be elected each year to serve five years. If any member at large shall be elected to any other office, a member at large shall be elected at once to serve out the remainder of his term. Sec. 3. These officers shall be elected by ballot at the annual meeting of the Society and their official terms shall commence with the close of the annual 233 234 AMERICAN SOCIETY OF ZOOLOGISTS meeting, except that the Secretary-Treasurer ‘shall be elected triennially and shall serve for three years. Sec. 4. The officers named in Section 1 shall discharge the duties usually assigned to their respective offices. Sec. 5. Vacancies in the board of officers, occurring from any cause, may be filled by election by ballot at any meeting of the Society. A vacancy in the Secretary-Treasurership occurring in the interval of the meetings of the Society may be filled by appointment, until the next annual meeting, by the Executive Committee. Sec. 6. At the annual meeting the President shall name a nominating com- mittee of three members. This committee shall make its nominations to the Secretary not less than one month before the next annual meeting. It shall be the duty of the Secretary to mail the list of nominations to all members of the Society at least two weeks before the annual meeting. Additional nominations for any office may be made in writing to the Secretary by any five members at any time previous to balloting. ArticLe IV MEETINGS OF THE SOCIETY Section 1. Unless previously determined by the Society the time and place of the annual meeting of the Society shall be determined by its Executive Com- mittee. Special meetings may be called and arranged for by the Executive Committee. Notices of such meetings shall be mailed to all members of the Society at least two weeks before the date set for the meeting. Sec. 2. Sections of the Society may be organized in any locality by not less than ten members, for the purpose of holding meetings for the presentation of scientific papers. Such sections shall have the right to elect their own officers and also associate members; provided, however, that associate membership in any section shall not confer membership in the Society. ARTICLE V QUORUM Twenty-five members shall constitute a quorum of the Society and four a quorum of its Executive Committee. Articte VI CHANGES IN THE CONSTITUTION Amendments to this Constitution may be adopted at any meeting of the Society by a two-thirds vote of the members present, upon the , following conditions: (a) The proposed amendment must be in writing and signed by at least five members of the Society. (b) This signed proposal must be in the hands of the Secretary at least one month before the meeting of the Society at which it is to be considered. (c) The Secretary shall mail copies of the proposed amendment to the mem- bers of the Society at least two weeks before the meeting. PROCEEDINGS 235 BY-LAWS DUES (1) The annual dues for members, unless remitted or changed by the vote of the Soeiety, shall be seven dollars. SECRETARY-TREASURER (2) The duties and privileges of the Secretary-Treasurer shall be as follows: (a) He shall keep the records and be in charge of the funds of the Society. (b) At the annual business meeting he shall present a statement to date of the funds of the Society. (c) Whenever the proper officers of a number of related societies shall have a conference with a view to determining a common time and place for the several annual metings, he shall act as the delegate or representative of this Society. (See also 5-a.) (d) He shall employ a typewriter or printer whenever in his judgment such employment will expedite the business of the Society, and (e) He shall be reimbursed out of the funds of the Society for expenses incurred in attending meetings of the Society. AUDITING COMMITTEE (3) The President shall annually appoint an auditing committee of two, who shall audit and report upon the financial record and statement of the Secretary- Treasurer at the meeting for which they were appointed. (4) The National Research Council allows the Society three representatives on the Division of Biology and Agriculture. Of these three representatives, one shall be elected each year to serve three years. The method of election shall be the same as that used in the election of the officers of the Society. AFFILIATION WITH THE AMERICAN SOCIETY OF NATURALISTS (5) It shall be the policy of the Society to hold meetings in both Eastern and Central-Western territory, and the distribution of the meetings between the two territories shall be determined in general on the basis of the representation of Eastern and Western members in the Society. See also 2-c PROGRAM RULES (6) In matters relating to programs for annual meetings the following rules shall be observed: (a) Papers shall be listed and presented according to subject matter in the following groups: 1. Comparative Anatomy; 2. Embryology; 3. Cytology; 4. Genetics; 5. Comparative and General Physiology; 6. Ecology, and 7. Miscel- laneous, or other groups at the discretion of the Secretary-Treasurer. (b) Whenever conditions require it the Executive Committee shall schedule two or more groups for the same hour and rearrange the program to bring to- gether papers on subjects of more general interest for meetings of the whole Society. The Committee, however, is instructed to avoid conflicts as much as possible. 236 AMERICAN SOCIETY OF ZOOLOGISTS (c) Papers shall be listed in their respective groups in the order received. When a member offers more than one paper those following the one designated first shall be placed at the end of the list and shall not be read until all first papers by members shall have been twice called for. (d) All papers not read when called for as listed shall be placed at the end of the group list, and, if not read when called for the second time, they shall be read by title only. (e) The titles of ‘‘introduced’’ papers shall be listed in the groups after the titles of papers to be read by members. Such papers shall be read by title only in case the entire program cannot be completed during four regular sessions for reading papers. (f) Fifteen minutes shall be the maximum time allowed for the presentation of a paper. (g) Abstracts of papers for publication in the proceedings of the Society must be handed to the Secretary-Treasurer or his representative before final adjourn- ment of the annual meeting. HISTORICAL REVIEW A review of the historical antecedents of the present-American Society of Zodlogists will be found in The Anatomical Record for January, 1917. The list of officers and meeting places of the present Society found in the same place is brought up to date and reprinted here. PROCEEDINGS 237 OFFICERS AND LIST OF MEMBERS! American Society or ZoéLoaists (AMALGAMATED) MEETING PLACES 1914—Philadelphia 1917--Minneapolis 1919—St. Louis 1915—Columbus 1918—Raltimore 1920—Chicago 1916—New York Officers for 1920 President. ..... Bre: SARUM ee dais FAS ae ah a's ve welds Gitman A. Drew TOMER e Sree taa nt neers tat aten sete css te clesvee CasweELL GRAVE SS Ee HUMAN Cin ee Te a toe es ea asin Seis vSlvjoenvn/ss on edasie W. C. ALLEE Executive Committee Term expires PMMTSPEL STC MUI IN Hees RTE a aie ruciace acter ee MPs atiteetie © selec s0.0 n04 sisfh aad o's apin ais 1920 MRE VU RIBLON eee te ee a craters c's onsen EEE NG low Vin So's cas bomva closing weenie 1921 AVC TOLER IRI RINE Ee wichic chen carte an are Be rvaicn Wie ere a oes aleis.c «ww nm pta ae eee me 1922 PUMOMCMMMBO RCN conc: ceert actions 118 SIS a ests ep cea s qe ensiees 1923 Rieee READY oS Pa tent cia an rae toa cece cinta a t's9.5 94% ons ep demiduee 1924 Representatives of the Society in the Division of Biology and Agriculture of the National Research Council Term ezpires EEC TESION sara aha ae teats aisle A hag Mol ad eatie Kida, «wins» cies) nies Welwaie'slaa hacen 1923 NOEL MEL SE arte dee nag ak hla e Wioinnde ate ARR AEE wes am Do alae RLaele wae 1921 SOR ME ARMM EL TY, We , OM ita wis! wk Sains ai orcleretere ia eR oA eis e x.x. 0s Ce oYelalare Ghee Sioa en 1922 EDITORIAL BOARD OF THE JOURNAL OF MORPHOLOGY Managing Editor (Term expires 1926). .............0s2eeeeeee ‘C. E. McCiuna Associate Editors J. S. KinGsitey Gary N. CALkins Or BARRO tLe Oa sly si oss nla dias eaten paiareiate aa nies wax © WiLurAM PatreNn E. G. Conxuin To serve NAMPA ALE Bis coi eehS. vba ch ASE aes 4M. F. Guyer W. M. WHEELER C. A. Kororp IG Serve WHiLOan ieee te ee ied te adadtes akeseacs « F. R. Litre J. T. Parrerson ‘The data given in this list is based on the last preceding list published in The Anatomical Record, Vol. 17, No. 5, with such corrections andadditions as have come to the attention of the Secretary. Please notify the Secretary of errors in this copy of the membership list that they may be corrected in the next pub- lished list. THE ANATOMICAL RECORD, VOL, 20, NO. 2 238 AMERICAN SOCIETY OF ZOOLOGISTS HONORARY MEMBER James Viscount Bryce, Hinpitear, Forest Row, Sussex, ENGLAND LIFE MEMBERS Anprews, Erxaan ALLEN, Ph.B. (Yale), Ph.D. (Johns Hopkins), Professor of Zodlogy, Johns Hopkins University, Baltimore, Md. Dean Basurorp, A.B. (College of City of New York), A.M., Ph.D. (Columbia), Professor of Vertebrate Zodlogy, Columbia University; Curator Emeritus of Fishes and Reptiles, American Museum Natural History, Riverdale-on-Hudson, New York. HensHAW, SAMUEL, Director of Museum of Comparative Zoélogy, 8 Fayerweather Street, Cambridge, Mass. Mayer, Atrrep GotpsporouGH, M.E. (Stevens Inst. Tech.), Se.D. (Harvard), Director Department Marine Biology, Carnegie Institution of Washington, 276 Nassau Street, Princeton, N. J. Mercatr, Maynarp Mayo, A.B., Se.D. (Oberlin), Ph.D. (Johns Hopkins), Orchard Laboratory, 128 Forest Street, Oberlin, Ohio. Moore, J. Percy, Ph.D. (Pennsylvania), Professor of Zodlogy, University of Pennsylvania, Philadelphia, Pa. Stites, Cuartes W., A.M., Ph.D. (Leipzig), S.M., S.D. (Wesleyan), Professor of Zoélogy, United States Public Health and Marine Hospital Service, Hygienic Laboratory. Twenty-fifth and E Streets, N.W., Washington, D. C. (October 1—May 1); Wilmington, N. C. (May-October 1). : MEMBERS Ackert, JAMES Epwarp, A.B., A.M., Ph.D. (University of Illinois), Professor of Zodlogy, Parasitologist Agr. Exp. Station; Kansas State Agricultural College, Manhattan, Kan. ALLEE, WARDER Ciypb, 8.B. (Earlham College), 8.M., Ph.D. (Chicago), Pro- fessor of Biology, Lake Forest College, Lake Forest, Ill. ALLEN, Bennet MILts, Ph.B. (DePauw), Ph.D. (Chicago), Professor of Zodlogy, University of Kansas, Lawrence, Kan. ALLEN, Ezra, A.B., A.M. (Bucknell), Ph.D. (University of Pennsylvania), Pro- fessor of Biology, Ursinus College, Collegeville, Pa. Arey, Lestre Brarnerp, Ph.D. (Harvard), Professor of Microscopic Anatomy, Northwestern University Medical School, 2431 Dearborn St., Chicago, IU. x BaitseLt, Grorce Aurrep, B.S. (Central College, Iowa), M.A., Ph.D. (Yale), Assistant Professor of Biology, Yale University, Osborn Zodlogical Labora- tory, Yale Station, New Haven, Conn. Baker, ArtHur Cuapen, B.S.A. (Toronto University), Ph.D. (George Wash- ington University), Entomological Assistant, Bureau of Entomology, Wash- ington, D. C. Banta, Artuur Manoun, A.B., A.M. (Indiana), Ph.D. (Harvard), Resident Investigator, Station for Experimental Evolution, Carnegie Institution, Cold Spring Harbor, Long Island, N. Y. : PROCEEDINGS 239 Barrows, Witu1aM Martin, B.S. (Michigan Agricultural College), 8.B., 8.M. (in biology) (Harvard), Department of Zodlogy and Entomology, Ohio State University, Columbus, Ohio. BarTeELMETz, GeorGE W., Ph.D. (Chicago), Associate Professor of Anatomy, University of Chicago, Chicago, Ill. BAUMGARTNER, WILLIAM JAcos, A.B., A.M. (Kansas), Associate Professor of Zodlogy, University of Kansas, 1209 Ohio Street, Lawrence, Kan. Beckwith, Cora Jrpson, B.S. (Michigan), M.A., Ph.D. (Columbia), Associate Professor of Zodlogy, Vassar College, Poughkeepsie, N. Y. Betiamy, Aubert W., Ph.D. (Chicago), Instructor in Zodlogy, University of Chicago, Chicago, Ill. Bicetow. Maurice ALpuevs, B.S. (Ohio Wesleyan), M.S. (Northwestern), Ph.D. (Harvard), Professor of Biology, Teachers College, 525 West 120th Street, New York City. Bicetow, Rosert Payne, 8.B. (Harvard), Ph.D. (Johns Hopkins), Associate Professor of Zodlogy and Parasitology, Massachusetts Institute of Technology, Cambridge, Mass. Brnrorp, Raymonp, B.S. (Earlham), S.M. (Chicago), Ph.D. (Johns Hopkins), President of Guilford College, Guilford, N. C. Boeck, Wriuram Cuartes, B.S., M.A., Ph.D., Hygiene Laboratory, U. 8. Public Health Service, Washington, D. C. ; Bortina, Auice MippteTton, A.B., A.M., Ph.D. (Bryn Mawr), Wellesley College, Wellesley, Mass. Boypen, E. A., Ph.D. (Harvard), Assistant Professor Comparative Anatomy, Harvard Medical School, 61 Clark Street, Newton Center, Mass. Bruner, Henry Lane, A.B. (Abingdon), Ph.D. (Freiburg), Professor of Biology, Butler College, 324 South Ritter Avenue, Indianapolis, Indiana. Bupineton, Ropert Attyn, B.A., M.A. (Williams), Professor of Zodlogy, Ober- lin College, Oberlin, Ohio. Burrows, Montrose T., A.B. (Kansas), M.D. (John: Hopkins), Washington, University Medical School, St. Louis, Mo. Byrnes, Estuer F., Ph.D. (Bryn Mawr), 193 Jefferson Avenue, Brooklyn, NY Cauxins, Gary N., B.S. (Mass. Inst. Tech.), Ph.D. (Columbia), Professor of Protozodlogy, Cohuaibics University, New York City. Catyert, Pattie Powe, Ph.D. (Pennsylvania), Professor of Zoblogy, Univer- sity of Pennsylvania, Zoédlogical Laboratory, Philadelphia, Pa. Carotuers, E. Eveanor, A.B., A.M., Ph.D., Zodlogical Building, University of Pennsylvania, Philadelphia, Pa. Carpenter, Frepertc WALTON, B.S. (New York University), A.M. Ph.D. (Har- vard), Professor of Biology, Trinity College, Hartford, Conn. : Cary, Lewis R., B.S., M.S (Maine), M.A., Ph.D. (Princeton), Assistant Pro- fessor of Biology, Princeton University, Princeton, N. J. CasreeL, Dana Brackenripos, A.B. (Allegheny), A.M. (Ohio Wesleyan), Ph.D. (University of Pennsylvania), Associate Professor of Zodlogy, University of Texas, Austin, Texas. Castie, Wituram E., A.B. (Denison), A.M., Ph.D. (Harvard), Professor of Zodlogy in Harvard University, Payson Road, Belmont, Mass. 240 AMERICAN SOCIETY OF ZOOLOGISTS Cuampers, Ropert, Jr., M.A. (Queen’s University, Can.), Ph.D. (Munich), Assistant Professor in Anatomy, Cornell University Medical College, 28th Street and First Avenue, New York City. Cuarman, Royau N., B.A., M.A. (Minnesota), Ph.D. (Cornell), Assistant Pri fessor of Animal Biology; Assistant Entomologist, Experiment Station, Uni- versity of Minnesota, Division of Entomology, University Farm, St. Paul, Minn. Cuester, WAYLAND Morean, A.B., A.M. (Colgate University), Professor of Biology, Colgate University, Hamilton, N. Y. Cuiip, Cuartes MANNING, Ph.B., M.S. (Wesleyan), Ph.D. (Leipzig), Professor of Zodlogy, Hull Zoédlogical Laboratory, University of Chicago, Chicago, Ill. CuvurcuiLt, Epwarp Perry, A.B. (lowa), Ph.D. (Johns Hopkins), Professor of Zodlogy, University of South Dakota, Vermillion, S. D. Ciemens, Lucy, B. A. (Smith), M. A. (Mt. Holyoke), Ph.D. (Cornell), 307 Dupont St., Toronto, Ont., Canada. Corn, WESLEY Rs PhD sie): Professor of Biology, Yale University, New Haven, Conn. ; Cocuitt, Grorce E., A.B., Ph.D. (Brown), Professor and Head of Dept. of Anatomy, University of Kansas, R.F.D. 9, Lawrence, Kan. ‘ Cour, Leon J., A.B. (Michigan), Ph.D. (Harvard), Professor of Experimental Breeding, College of Agriculture, University of Wisconsin, Madison, Wis. Couron, Haroup Seuirrs, B.S., M.A., Ph.D. (Pennsylvania), Assistant Profes- sor of Zodlogy, University of Pennsylvania, Philadelphia, Pa. Concpon, EpGar Davinson, A.B., A.M. (Syracuse), Ph.D. (Harvard), Leland Stanford Jr. University, 330 Coleridge Ave, Palo Alto, Cal. Conkutn, Epwin Grant, Ph.D. (Johns Hopkins), Sc.D. (Pennsylvania), Pro- fessor of Biology, Princeton University, Princeton, N. J. CoreLanp, Manron, S.B., S.M., Ph.D. (Harvard), Professor of Biology, Bow- doin College, Brunswick, Maine. Cort, Wituram Watrter, A.B. (Colorado College), A.M., Ph.D. (University of Illinois), School of Hygiene and Public Health, 310 W. Monument St., Balti- more, Md. Crampton, Henry Epwarp, A.B., Ph.D.; (Columbia), Professor of Zodlogy, Barnard College, Columbia University, Curator of Invertebrate Zodlogy, American Museum of Natural History, New York City. Crozier, Witu1aM Joun, B.S. (College of the City of New York), A. M.,Ph.D. (Harvard), Professor of Zodlogy, Rutgers College, New Brunswick, N. J. Curtis, Maynte Rose, A.B., A.M., Ph.D. (Michigan), Assistant Biologist, Maine Agricultural Experiment Station, Orono, Maine. ~ Curtis, Winterton Conway, A.B., A.M. (Williams), Ph.D. (Johns Hopkins), Professor of Zoélogy, University of Missouri, 208 Hicks Ave., Columbia, Mo. Dantoren, Unric, A.B., M.S. (Princeton), Professor of Biology, Princeton Uni- versity, 204 Guyot Hall, Princeton, N. J. Dantet, J(ouNn) F(ranxutn), 8.B. (University of Chicago), Ph.D. (Johns Hop- kins), Professor of Zodlogy, University of California, 100 Woodmont Ave., Berkeley, Cal. Davenport, Cuartes Benepicr, Ph.D. (Harvard), Director of Department of Experimental Evolution, Carnegie Institution of Washington, Cold Spring Harbor, Long Island, N. Y. PROCEEDINGS 241 Davenport, Gertrupe Crorry, B.S. (University of Kansas), Cold Spring Har- bor, Long Island, N. Y. Davis, Hersert Spencer, Ph.B. (Wesleyan), Ph.D. (Harvard), Professor of Zodlogy, University of Florida, Gainesville, Fla. Dawson, James Artuur, A.B. (Dalhousie), A.M., Ph.D. (Yale), Professor of Biology, Dalhousie University, Halifax, Nova Scotia, Canada. Day, Epwarp Carrot, A.B. (Hamilton), A.M., Sc.D. (Harvard), Assistant Professor of Zodlogy, University of Cincinnati, Cincinnati, Ohio. Der.ersen, Joun A., A.B. (Dartmouth), A.M., Sc.D. (Harvard), Assistant Professor of Genetics, University of Illinois, College of Agriculture, 506 Michigan Avenue, Urbana, Illinois. Detwiter, SAMvEL RANDALL, Ph.B., M.A., Ph.D. (Yale), Instructor in Anat- omy, Peking Union Medical College, Peking, China. Dopps, GipEon S., B.A., M.A. (Colorado), Ph.D. (Pennsylvania), Assistant Professor of Zodlogy, University of West Virginia, Morgantown, West Vir- ginia. Douuey, WituiaM Ler, Jr., A.B., A.M. (Randolph-Macon), Ph.D. (Johns Hop- kins), Professor of Biology, Randolph-Macon College, Ashland, Va. Drew, Gruman A., B.S. (State University of Iowa), Ph.D. (Johns Hopkins), Assistant Director, Marine Biological Laboratory, Woods Hole, Mass. Dunn, Lestie Ciarence, 8.B. (Dartmouth), 8.M., Se.D. (Harvard), Poultry Biologist, Connecticut Agricultural Experiment Station, Storrs, Conn. Dvurorte, Ernest Metvitie, M.Se., B.S.A. (McGill), Instructor in Zodlogy and Entomology, Macdonald College, Macdonald College, P. O. Province Quebec, Canada, Epmonpson, Cuartes Howarp, Ph.B., M.S., Ph.D. (lowa University), Pro- fessor of Zodlogy, Director of Research Laboratory, College of Hawaii, Hono- lulu. Epwarps, Caartes Lincoin, B.S. (Lombard and Indiana), A.M. (Indiana), Ph.D. (University of Leipzig), Director, Department of Nature Study, Los Angeles City Schools, 1032 West 39th Place, Los Angeles, Calif. EIGENMANN, Cart H., A.B., A.M., Ph.D. (Indiana), Research Professor and Dean of the Graduate School, Indiana University, Bloomington, Ind. Enpers, Howarp Epwin, B.S. (Lebanon Valley College), B.S., M.S. (Michigan), Ph.D. (Johns Hopkins), Associate Professor of Zoédlogy and in charge of Biology, Purdue University; Summer School Staff, Dept. Zoology, Indiana University, 107 Fowler Ave., West Lafayette, Indiana. ErpMaAnn, Ruopa, Ph.D. (Munich), Berlin-Wilmersdorf, Nassauische str. 17", Germany. Estrerty, Carvin O., A.B., A.M. (California), Ph.D. (Harvard), Zodlogist, Scripps Institution, La Jolla, California; Professor of Biology, Occidental College, Los Angeles, Calif. Fasten, Natuan, B.S. (College of City of New York), Ph.D. (Wisconsin), Associate Professor of Zoélogy, Oregon Agricultural College, Corvallis, Ore. Ferris, Harry Burr, B.A., M.D. (Yale), E. K. Hunt Professor of Anatomy, Medical Department, Yale University, 395 St. Ronan, New Haven, Conn. Fox, Henry, B.S., M.A., Ph.D. (University of Pennsylvania), Professor of Biol- ogy, Mercer University, Macon, Ga. 242 AMERICAN SOCIETY OF ZOOLOGISTS Fraser, Cuartes McLean, A.B., A.M. (Toronto), Ph.D. (Iowa), Professor of Zoblogy, University of British Columbia and Director of Marine Biological Station, Nanaimo, University of B. C., Vancouver, B. C., or Biological Station, Nanaimo, B. C. Gaap, Simon Henry, B.S. (Cornell), Emeritus Professor of Histology and Embry- ology, Cornell University, Stimson Hall, Ithaca, N. Y. Gattoway, Tuomas W., A.B., A.M., Ph.D. (Cumberland), A.M. (Harvard), Litt.D. (Missouri Valley), 105 W. 40th St., New York City. Garman, Harrison, D.Se. (Kentucky), Professor of Entomology and Zodlogy, Kentucky Agricultural Experiment Station; State Entomologist, Lexington, Ky. Ger, Witson, B.S. (Clemson), M.A. (University of South Carolina), Ph.D. (University of California), University of South Carolina, Columbia, S. C. GerouLp, Joun H., Litt.B. (Dartmouth), A.B., A.M., Ph.D. (Harvard), Pro- fessor of Biology, Dartmouth College, 36 Occom Ridge, Hanover, N. H. Guaser, Orro Cuarues, A.B., Ph.D. (Johns Hopkins), Professor of Biology, Amherst College, Amherst, Mass. Goutprars, A. J., B.S. (College of City of New York), Ph.D. (Columbia); Pro- fessor of Biology, College of City of New York, Convent Ave., New York City. Gotpscumipt, Rickarp B., Ph.D. (Heidelberg), Kaiser Wilhelm Institut fir Biologie, Berlin-Lichterfelde 8, Germany. Goupsmiti, WILLIAM Marton, B.Pd., A.B., A.M., Ph.D. (Indiana), Professor of Biology, Southwestern College, Winfield, Kansas. Goopate, Huserr Dana, Ph.D. (Columbia), Research Biologist, Massachusetts Agricultural Experiment Station, North Amherst, Mass. Goopricu, Husert Baker, B.S. (Amherst), M.A., Ph.D. (Columbia), Instructor in Zoélogy, Wesleyan University, Middletown, Conn. Granam, Joun YounG, Ph.D. (Munich), Professor of Biology, University of Ala- bama, University, Ala. Grave, Bensamin H., B.S., (Earlham) M.S. (Carleton), Ph.D. (Johns Hopkins), Professor of Zoélogy, Wabash College, Crawfordsville, Ind. Grave, Caswett, B.S. (Earlham), Ph.D. (Johns Hopkins), Professor of Zoélogy, Washington University, St. Louis, Mo. : Greoory, Louise H., A.B. (Vassar), A.M. Ph.D. (Columbia), Instructor in Zodlogy, Barnard College, New York City. Grier, Norman McDowex tt, 8.B., A.M., Ph.D. (Pittsburgh), Professor of Biol- ogy, Washington and Jefferson College, Washington, Pa. Grirrin, LAWRENCE Epmonps, A.B., Ph.B. (Hamline), Ph.D. (Johns Hopkins), Reed College, Portland, Oregon. Gross, Atrrep O., A.B. (Illinois), Ph.D. (Harvard), Assistant Professor of Zoblogy, Bowdoin College, Brunswick, Maine. F Gusertet, J. E., A.M., Ph.D. (Illinois), Parasitologist, Oklahoma A. and M. College, Stillwater, Okla. Gupcer, BE. W., B.S., M.S. (Nashville), Ph.D. (Johns Hopkins), American Museum of Natural History, New York City. Guuick, Apprson, A.B. (Oberlin), A.M. (Harvard), Ph.D. (Wurzburg, Germany), Assistant Professor in Physiology, University of Missouri, 903 Lake Street, Columbia, Mo. PROCEEDINGS 243 Guyer, Micnaet F., B.S. (Chicago), A.M. (Nebraska), Ph.D. (Chicago), Pro- fessor of Zoblogy, University of Wisconsin, Madison, Wis. Haut, Maurice Crowruer, 8.B. (Colorado), M.A. (Nebraska), Ph.D. (George Washington), D.V.M. (George Washington), Senior Zodélogist, Zodlogical Division, Bureau of Animal Industry, Washington, D. C. Hamaker, Joun Irvin, A.B. (Kansas), A.B., A.M., Ph.D. (Harvard), Professor of Biology, Randolph-Macon Woman’s College, 12 Princeton Street, Lynch- burg, Va. Hance, R. T., A.B., M.A., Ph.D. (Pennsylvania), Instructor in Zodlogy, Uni- versity of Pennsylvania, Zodlogical Laboratory, University of Pennsylvania, Philadelphia, Pa. Hanson, Frank Brarr, A.B. (George Washington), A.M. (Illinois), Ph.D. (American University), Assistant Professor of Zodlogy, Washington Uni- versity, Department of Zoélogy, Washington University, St. Louis, Mo. Harairr, CHartes W., Ph.D. (Ohio University), Professor of Zoélogy, Director of Laboratories, Syracuse University, Syracuse, N. Y. Hareitr, George Tuomas, Ph.B. (Syracuse), A.M. (Nebraska), Ph.D. (Har- vard), Associate Professor of Zoélogy, Syracuse University, 909 Walnut Ave., Syracuse, N.Y. Harmon, Mary Tueresa, A.B., M.A., Ph.D. (Indiana), Assistant Professor of Zodlogy, Kansas State Agricultural College, Manhattan, Kan. Harper, Evcene Howarp, A.B. (Oberlin), A.M. (Harvard), Ph.D. (Chicago), Bedford, Va. Harrison, Ross Granvitie, Ph.D. (Johns Hopkins), M.D. (Bonn), Bronson Professor of Comparative Anatomy, Yale University, 142 Huntington St., New Haven, Conn. Harman, Cart G., Ph.D. (Texas), Associate Professor of Zodlogy, University of Texas, 511 W. 38rd St., Austin, Texas. Heatu, Haroutp, A.B. (Ohio Wesleyan), Ph.D. (Pennsylvania), Professor of Invertebrate Zoélogy, Leland Stanford University, Palo Alto, Calif. Hecut, Seria, Ph.D. (Harvard), Assistant Professor of Physiology, Creighton Medical College, Omaha, Neb. Heoner, Rosert W., B.S., M.S. (Chicago), Ph.D. (Wisconsin), Instructor in Protozoédlogy, School of Hygiene and Public Health, Johns Hopkins Uni- versily, Baltimore, Md. Herisren, L.V., Ph.D. (Chicago), Instructor in Zodlogy, University of Michigan, Ann Arbor, Mich. HencuMAN, ANNIE P., Box 34, Jaffrey, N. H. Herrick, Cxarves Jupson, Ph.D. (Columbia), Professor of Neurology, Anatom- ical Laboratory, University of Chicago, Chicago, Ill. Herrick, Francts Hopart, A.B. (Dartmouth), Ph.D. (Johns Hopkins), D.Sc. (Pittsburgh), Professor of Biology, Western Reserve University, Adelbert College, Cleveland, Ohio. Hess, Water N., A.B. (Oberlin), A.M., Ph.D. (Cornell), Professor of Biology, De Pauw University, Greencastle, Indiana. Hickernewi, L. B., A.B., A.M., Ph.D. (Princeton), Assistant Professor of Zodlogy, Syracuse University, 1052 Ackerman Ave., Syracuse, N. Y. 244 AMERICAN SOCIETY OF ZOOLOGISTS Hitron, WittiaM Arwoop, B.S., Ph.D. (Cornell), Professor of Zoélogy, Pomona College, Claremont, California; Director Laguna Marine Biological Labora- tory; Editor, Journal of Entomology and Zoélogy, Claremont, Calif. Hogue, Mary Jane, A.B. (Goucher), Ph.D. (Wiirzburg), Fellow in Protozodlogy, School of Hygiene and Public Health, Johns Hopkins University, 821 Charles St., Baltimore, Md. Houmes, Samvuet J., B.S., M.S. (California), Ph.D. (Chicago), Professor of Zoblogy, University of California, Berkeley, Calif. Hooker, Davenport, B.A.,M.A., Ph.D, (Yale), Professor of Anatomy, University of Pittsburgh, School of Medicine, University of Pittsburgh, Pittsburgh, Pa. Houser, Gitpert Loaan, B.S., M.S. (lowa), Ph.D. (Johns Hopkins), Professor of Animal Biology and Director of the Laboratories of Animal Biology, State University of Iowa, 430 Iowa Avenue, Iowa City, Iowa. Howarp, A. D., B.S., (Amherst), M. 8S. (Northwestern), Ph.D. (Harvard), Sei- entific Assistant, United States Bureau of Fisheries, Fairport Biological Laboratory, United States Biological Laboratory, Fairport, Iowa. Hunt, Harrison Ranpatt, B.S., Allegheny College, M.A., Ph.D. (Harvard), Professor of Zoélogy, University of Mississippi, Oxford, Miss. HuntsMAN, ArcHIBALD Gowantock, B.A., (M.B. Toronto), F.R.S.C. (Canada), Professor of Marine Biology, Biological Department, University of Toronto, Toronto, Canada. Hussakor, Louis, B.S. (College of the City of New York), Ph.D. (Columbia), Curator of Ichthyology, American Museum of Natural History, 1537 60th Street, Borough Park, Brooklyn, N. Y. Hoxtuey, JuLIAN Sorevu, B.A. (Oxford), Senior Demonstrator, Department of Zoélogy and Comparative Anatomy, Fellow of New College, Oxford, The Museum, Oxford, England. Hyper, Roscor Raymonp, A.B., A.M. (Indiana), Ph.D. (Columbia), Associate in Immunology, School of Hygiene and Public Health, Johns Hopkins Uni- versity, 310-312 W. Monument St., Baltimore, Maryland. Hyman, L. H., Ph.D. (Chicago), Research Assistant, University of Chicago, Hull Zoblogical Laboratory, University of Chicago, Chicago, Illinois. InseN, HeMAN Lawnitz, B.S., M.S., Ph.D. (Wisconsin), Professor of Genetics, Department of Animal Husbandry, Kansas State Agricultural College, Man- hattan, Kan. Isety, Freperick B., B.S. (Fairmount), M.S. (Chicago), Professor of Biology, Culver-Stockton College, Canton, Mo. Jacops, Merket Henry, A.B., Ph.D. (Pennsylvania), Assistant Professor of Zodlogy, Zodlogical Laboratory, University of Pennsylvania, Philadelphia, Pa. Jenninos, Herserr 8., B.S. (Michigan), A.M., Ph.D. (Harvard), LL.D. (Clark), — 8.D. (Michigan), Henry Walters Professor of Zoédlogy and Director of the Zoological Laboratory, Johns Hopkins University, Baltimore, Md. Jewett, Minna E., A.B. (Colorado College), A.M., Ph.D. (Illinois), Assistant Professor of Zodlogy, Milwaukee-Downer College, Milwaukee, Wisconsin, Jos, Tueste T., A.B., A.M., Ph.D., Associate Professor of Anatomy, Loyola University School of Medicine, 706 S. Lincoln St., Chicago, Ill. JOHANNSEN, Oskar Avoustus, B.S. (Illinois), A.M. (Cornell), Ph.D. (Cornell), Professor of Entomology, Cornell University, College of Agriculture, 234 Parkway, Ithaca, N. Y. PROCEEDINGS 245 Jounson, Cuarves Evucene, B.A., M.A., Ph.D. (Minnesota) Assistant Profes- sor of Zoélogy, University of Kansas, 616 West 17th Street, Lawrence, Kansas. Jounston, Joun B., Ph.D. (Michigan), Professor of Comparative Neurology, University of Minnesota, Minneapolis, Minn. Jorpan, Harvey Ernest, B.A., M.A. (Lehigh), Ph.D. (Princeton), Professor of Histology and Embryology, University of Virginia, Charlottesville, Va. Jupay, Cuancry, A.B., A.M. (Indiana), Biologist, Wisconsin Geological and Natural History Survey; Lecturer in Zoélogy, University of Wisconsin, Madison, Wisconsin. Just, Ernest Everett, Ph.D. (Chicago), Professor of Zoélogy, Howard Uni- versity, Washington, D. C., 412 T Street, Washington, D. C. Kampmerer, Orro F., B.A. (Iowa), Ph.D. (Princeton), Professor and Director of the Department of Anatomy, Marquette School of Medicine, 4th and Reservoir Sts., Milwaukee, Wis. Kepner, Witu1AM Auuison, A.B., A.M. (Franklin and Marshall College, Lan- caster, Pa.), Ph.D. (Virginia), Associate Professor of Biology, University of Virginia, University, Va. ‘ Kincaip, Trevor, B.S., M.A. (University of Washington), Head of Department of Zodlogy, University of Washington, Seattle, Wash. Kinprep, James Ernest, A.B., A.M., Ph.D. (Illinois), Instructor in Biology, Western Reserve Dental School, Cleveland, Ohio, 1353 E. 9th St., Cleveland, Ohio. Kine, Heven Dean, A.B. (Vassar), A.M., Ph.D. (Bryn Mawr), Assistant Pro- fessor of Embryology, The Wistar Institute of Anatomy and Biology, The Wistar Institute, Thirty-sixth St. and Woodland Ave., West Philadelphia, Pa. Kinesspury, Bensamin Freeman, Ph.D. (Cornell), M.D. (Freiburg), Professor of Histology and Embryology, Cornell University, 2S. Avenue, Ithaca, N. ¥ Kinestey, Joun Sterutnec, A.B. (Williams), Sc.D. (Princeton), Professor of Zoblogy, University of Illinois, Urbana, Il. Kirksaam, Wituram Barri, B.A., M.A., Ph.D. (Yale), Assistant Professor of Biology, Sheffield Sciaatitic School, Y ale University, 103 Everit Street, New Haven, Conn. Knower, Henry McE., A.B., Ph.D. (Johns Hopkins), Professor of Anatomy, Medical Department, University of Cincinnati, Cincinnati, Ohio. Kororp, Cuartes Atwoop, A.B.,-Se.D. (Hon.) (Oberlin), A-M., Ph. D. (Harvard), Sc.D. (Hon.) (University of Wales). Professor of Zodlogy and Assistant Director of the Scripps Institution for Biological Research, University of California, Berkeley, Calif. Kornuavser, Sipney, A.B. (Pittsburgh), A.M. Ph.D. (Harvard), Professor of Zodlogy, Denison University, Granville, O. Krecker, Freperic H., A.B., Ph.D. (Princeton), A.M. (Cornell), Assistant Professor of Zodlogy, Ohio State University, Columbus, Ohio. Kriss, Hersert Guy, A.B. (Oberlin), Ph.D. (Pennsylvania), B.A. (Union), Assistant in Zoélogy, University of Pennsylvania, Philadelphia, Pa. Kupo, Rokusasuro, D.Ag.Se. (Tokio), Instructor in Zoédlogy, University of Illinois, Urbana, Illinois. Kunket, Beverty Wauau, Ph.B., Ph.D. (Yale), Professor of Biology, Lafayette College, Easton, Pa, * Kuntz, Auvpert, B.A. (Morningside), Ph.D. (State University of Iowa), M.D. (St. Louis University School of Medicine), Professor of Anatomy and Biology, St. Louis University School of Medicine, 1402 S. Grand Ave., St. Louis, Mo. 246 AMERICAN SOCIBTY OF ZOOLOGISTS Lanpacrs, Francis Leroy, A.B. (Ohio), Ph.D. (Chicago), Professor of Anat- omy, Ohio State University, Columbus, Ohio. Lane, Henry Hieeins, Ph.B. (DePauw), A.M. (Indiana), Ph.D. (Princeton), Professor of Zoélogy, Phillips University, Hast Enid, Oklahoma. La Rue, Georce R., B.S. (Doane), A.M. (Nebraska), Ph.D. (Illinois), Assistant Professor of Zodlogy, University of Michigan, Ann Arbor, Mich. Lasatey, Kart Spencer, A.B. (West Virginia), M.S. (Pittsburgh), Ph.D. (Johns Hopkins), Assistant Professor of Psychology, University of Minnesota, Minne- apolis, Minn. Laurens, Henry, A.M. (Charleston), Ph.D. (Harvard), Assistant Professor of Biology, Yale College, Osborn Zoélogical Laboratory, Yale University, New Haven, Conn. Ler, Tomas G., B.S., M.D. (Pennsylvania), Professor of Comparative Anat- omy, University of Minnesota, Institute of Anatomy, Minneapolis, Minn. Lerevre, Groree, A.B., Ph.D. (Johns Hopkins), Professor of Zodlogy, Univer- sity of Missouri, Columbia, Mo. Litutr, Frank R., B.A. (Toronto); Ph.D. (Chicago), Professor of Embryology and Chairman of the Department of Zodlogy, University of Chicago; Direc- tor, Marine Biological Laboratory, Woods Hole, Mass., University of Chicago, Chicago, Ill. Linum, Ravpu S., A.B. (Toronto), Ph.D. (Chicago), Biologist, Nela Research Laboratories, Department of Pure Science, Nela Research Laboratories, Nela Park, Cleveland, Ohio. Linton, Epwin, A.B., S.M. (Washington and Jefferson), Ph.D. (Yale), 1408 Rosemary Lane, Columbia, Mo. Lieprncorr, WititAm Apams, A.B. (Illinois College), S.B. (Iowa State), S.M. Ph.D., (Wisconsin), Professor of Poultry Husbandry and Poultry Husband- man, Kansas State Agricultural College, Manhattan, Kansas. Loey, Wini1aM ALBERT, Ph.D. (Chicago), Sc.D. (Hon.) (Michigan), Professor of Zodlogy and Director of the Zodlogical Laboratory, Northwestern Univer- sity, 1745 Arrington Ave., Evanston, Ill. Lona, Josera A., 8.B., A.M., Ph.D. (Harvard), Assistant Professor of Embry- ology, University of California, 1584 La Loma Avenue, Berkeley, Cal. Lonetey, Witu1AM, M.A., Ph.D. (Yale), Professor of Biology, Goucher College, Baitimore, Md. Lunn, Evmer J., Ph.D. (Johns Hopkins University), Assistant Professor of Zoblogy, University of Minnesota, Minneapolis, Minn: Lurz, Frank E., A.B. (Haverford), A.M., Ph.D. (Chicago), Associate Curator of Invertebrate Zoélogy, American Museum of Natural means? 77th Street and Central Park West, New York City. Lyncu, Ruru SrockinG (Mra. ), A.B. (Goucher), Ph.D. (Johns Hoping Inde- pendent Research, The Johns Hopkins Medical School, 3A Seville Apartments, Lake Drive, Baltimore, Md. McCuung, ©. E., Ph.G., A.B., A.M., Ph.D. (Kansas), Professor of Zodlogy, Uni- versity of Pennsylvania, Chairman Division of Biology and Agriculture, National Research Council, Washington, D. C., or Zodlogical Laboratory, University of Pennsylvania, Philadelphia, Pa. PROCEEDINGS 247 McCuore, Cuartes F. W., A.B., A.M. (Princeton), D.Se. (Columbia), Professor of Zodlogy, Princeton University, Princeton, N. J. McCuttocu, Irene, Ph.D. (California), Professor of Biology, Sophie Newcomb College, New Orleans, La. MacCourpy, Hansrortu M., A.B. (Ohio Wesleyan), A.M., Ph.D. (Harvard), Professor of Biology, Alma College, 701 Center St., Alma, Mich. MacDowett, Epwin Car.eton, A.B. (Swarthmore), S.M., Se.D. (Harvard), Research Investigator, Station for Experimental Evolution, Carnegie Insti- tution of Washington, Cold Spring Harbor, Long Island, N. Y. MacGiiirvray, ALEXANDER Dyer, Ph.D. (Cornell), Associate Professor Sys- tematic Entomology, University of Illinois, 603 West Michigan Ave., Urbana, ll. McGrecor, James Howarp, B.S. (Ohio State University), M.A., Ph.D. (Colum- bia), Associate Professor of Zodlogy, Columbia University, New York City. McInpoo, Norman Evcene, A.B., A.M. (Indiana), Ph.D. (Pennsylvania), Insect Physiologist, Bureau of Entomology, Washington, D. C. Magartu, Tuomas Byrp, Ph.B. (Emory University), M.S. (Millikin University), Ph.D. (University of Illinois), M.D. (University of Illinois), Parasitologist, Mayo Clinic, Rochester, Minn. _ Mark, Epwarp L., A.B. (Michigan), Ph.D. (Leipzig), LL.D. (Michigan), LL.D. (Wisconsin), Hersey Professor of Anatomy and Director of the Zodlogical Laboratory, Harvard University, 109 Irving Street, Cambridge, Mass. MarsHat.t, Ruts, B.S. , M.S. (Wisconsin), Ph.D. (Nebraska), Professor of Biol- ogy, Rockford College, Rockford, Ill. Marsuatt, WILLIAM StTantey, B.S. (Swarthmore), Ph.D. (Leipzig), Associate Professor of Entomology, University of Wisconsin, 139 East Gilman Street, Madison, Wisconsin. Mast, Samuet Orrmar, B.S. (Michigan), Ph.D. (Harvard), M.Pd. (Michigan Normal College), Professor of Zoédlogy, Johns Hopkins University, Baltimore, Md. Mavor, James Wart, B.A. (Cantab.), Ph.D. (Harvard), Assistant Professor of Zoblogy, Union College, Schenectady, N. Y. May, Henry G., 8.B. (Rochester), Ph.D. (Illinois), Professor of Bacteriology Rhode Island State College and Chief, Division of Animal Breeding and Pathology, Agr. Exp. Station, Kingston, R. I. Meap, Atsert Davis, A.B. (Middlebury), A.M. (Brown), Ph.D. (Chicago), Se.D. (Pittsburgh), Professor of Biology, Brown University, 283 Wayland Avenue, Providence, R. I. Mertz, Cuartes W., B.A. (Pomona), Ph.D. (Columbia), Station for Experi- mental Evolution, Carnegie Institution of Washington, Cold Spring Harbor, Long Island, N.Y. Meyer, Artravr Witttam, B.S. (Wisconsin), M.D. (Johns Hopkins), Professor of Anatomy, Stanford Jr. University, 121 Waverly Street, Palo Alto, Cal. Mipp.eton, Austin Raurn, A.B., Ph.D. (Johns Hopkins), Professor of Zodlogy, Director of Department of Biology, University of Louisville, 1st and Chestnut Sts., Louisville, Ky. Mrwnicu, Dwicut Eimer, A.B. (Miami), Ph.D. (Harvard), Instructor in Animal Biology, University of Minnesota, Minneapolis. 248 AMERICAN SOCIETY OF ZOOLOGISTS Moenkuaus, Witui1AM J., A.B. (Indiana), Ph.D. (Chicago), Professor of Physi- ology, Indiana University, 501 Fess Avenue, Bloomington, Ind. Moopy, Junta Eveanor, B.S., M.A. (Mt. Holyoke), Ph.D. (Columbia), Associ- ate Professor of Zodlogy, Wellesley College, 15 Appleby Read, Wellesley, - Mass. Moore, Cart R., B.S., A.M. (Drury), Ph.D. (Chicago), Instructor in Zodlogy, University of Chicago, Chicago, Ill. Morgan, Ann Haven, A.B., Ph.D. (Cornell), Professor of Zoélogy, Mt. Holyoke College, South Hadley, Mass. Morgan, THomas Hunt, B.S. (Kentucky), Ph.D. (Johns Hopkins), Professor of Experimental Zoélogy, Columbia University, New York City. Moroutis, Sercius, A.M. (Columbia), Ph.D. (Harvard), Professor of Biochem- istry and Physiology, Creighton University Medical School, Omaha, Neb. Morriti, Atpro Davin, B.S., M.S. (Dartmouth), Professor of Biology, Hamil- ton College, Clinton, Oneida County, N.Y. Morriti, Cuartes V., A.M., Ph.D. (Columbia), Assistant Professor of Anat- omy, Cornell University Medical College, 28th Street and First Avenue, New York City. Mosuer, Epna, B.S. (Cornell), Ph.D. (Illinois), Acting Professor of Biology, University of New Mexico, Albuquerque, N. Mex. MvLLENIX, Roun CLARKE, A.B., A.M. (Wheaton), Ph.D. (Harvard), Professor of Zoélogy, Lawrence College, 461 Washington St., Appleton, Wisconsin. Mutter, Herman J., A.B., A.M., Ph.D. (Columbia), Dept. of Zoélogy, Univ. of Texas, Austin, Texas. Mourrkowsk!I, Richarp AntHony, A.B., A.M., Ph.D. (Wisconsin), Assistant Professor of Zodlogy and Entomology, University of Idaho, Moscow, Idaho, Nasours, Ropert K., Ph.D. (Chicago), Professor of Zodlogy and Experiment Station Zodlogist, Kansas Agricultural College, Manhattan, Kansas. Nacutries, Henry Francis, B.S. (Minnesota), Professor of Animal Biology and Head of the Department, University of Minnesota, Minneapolis, Minn. Nea, Herpert Vincent, A.B., A.M., Ph.D. (Harvard), Professor of Zoélogy, Tufts College, 6% Midford Hillside, Tufts College, Mass. Netson, James ALLEN, Ph.B. (Kenyon College), Ph.D. (Pennsylvania), Collab- orator Bureau of Entomology, U. S. Department of Agriculture, Route 3, Mount Vernon, Ohio. Netson, THurLow, Cuase B.A. (Rutgers), Ph.D. (Wisconsin), Asst. Professor of Zoédlogy, Rutgers College, Biologist, State Board of Shell Fisheries, 855 Adelaide Ave., New Brunswick, N. J. NEWMAN, Honat1o Hacxert, B. re , (MeMaster), Ph.D. (Chicago), Professor of Zoodlogy and Dean in the College of Science, University of Chicago, Chicago, Ill. Norris, Harry Waupo, A.B., A.M. (Grinnell), Professor of Zoédlogy, Grinnell College, Grinnell, Towa. Nowy, Napine (Miss), A.B., A.M. (Kansas), Assistant Professor of Zodlogy, University of Kansas, 1144 Louisiana St., Lawrence, Kansas. Nortina, C. C., A.B., A.M. (Blackburn University), Professor of Zoélogy, State University of Iowa, Iowa City, Towa. O’Donocuur, Cuartes H., D.Sc. (London), F.Z.8., Professor of Zodlogy, Uni- versity of Manitoba, W innipeg; Canada. PROCEEDINGS 249 Oumstep, J. M. D., Ph.D. (Harvard), Instructor in Physiology, Toronto Uni- versity, 7'oronto, Canada. Ossorn, Henry Fatrrievp, A.B., Sc.D. (Princeton), LL.D. (Hon.) (Trinity, Princeton, Columbia), D.Sc. (Hon.) (Cambridge University), Ph.D. (Hon.) (University of Christiana, Upsala); Research Professor of Zoélogy, Colum- bia; President Board of Trustees, American Museum Natural History; Cura- tor Emeritus, Department of Vertebrate Paleontology, Vertebrate Paleon- tologist, United States Geological Survey; American Museum of Natural History, Seventy-seventh Street and Central Park West, New York City. Osporn, Henry Lesuir, A.B. (Wesleyan), Ph.D. (Johns Hopkins), Professor of Biology, Hamline University, 1500 Hewitt Avenue, St. Paul, Minn. Ossorn, Hersenrt, B.Sc., M.Sc., D.Sc. (lowa State College), Research Professor Ohio State University, 1952 Concord Road, Upper Arlington, Columbus, Ohio. OssurN, Raymonp C., Ph.D. (Columbia), Professor of Zoélogy, Ohio State University, Columbus, Ohio. Packarp, Cuartes, M.S., Ph.D., Peking Union Medical College, Peking, China. PaInTeR, THEOPHILUS SHICKEL, A.B., (Roanoke) A.M., Ph.D. (Yale), Adjunct Professor of Zoélogy, University of Texas, Austin, Texas. Parker, GeorGe Howanrp, S.B., Se.D. (Harvard), Professor of Zodlogy, Harvard University, 16 Berkeley Street, Cambridge, Mass. Parsuiey, H. M., A.B., A.M., Sc.D. (Harvard), Associate Professor of Zoélogy, Smith College, Department of Zodlogy, Smith College, Northampton, Mass. Parren, Braptey Merritt, A.B. (Dartmouth), A.M., Ph.D.. (Harvard), Assist- ant Professor of Histology and Embryology, Western Reserve University Medical School, 1353 East 9th Street, Cleveland, Ohio. Parren, Witu1aM, B.S., (Harvard) M.A., Ph.D. (Leipzig), Professor of Zodlogy, Dartmouth College, Hanover, N. H. Patrerson, Joun Tomas, B.S. (Wooster), Ph.D. (Chicago), Professor of Zoél- ogy, University of Texas, University Station, Austin, Texas. Payne, Fernanvus, A.B., A.M. (Indiana), Ph.D. (Columbia), Professor of Zodlogy, Indiana University, Bloomington, Indiana. Peart, Raymonp, A.B. (Dartmouth), Ph.D. (Michigan), D.S. (Dartmouth), LL.D. (Maine), Professor of Biometry and Vital Statistics, School of Hygiene and Public Health, Johns Hopkins University, Baltimore, Md. Pearse, ArtrHur Sperry, B.S., A.M. (Nebraska), Ph.D. (Harvard), Professor of Zodlogy, University of Wisconsin, Madison, Wis. Peesies, Frorence, A.B. (Goucher), Ph.D. (Bryn Mawr), Associate Professor of Physiology, Bryn Mawr College, Bryn Mawr, Pa. Perkins, Henry F., A.B. (Vermont), Ph.D. (Johns Hopkins), Professor of Zodl- ogy, University of Vermont, 205 South Prospect Street, Burlington, Vt. PerrRUNKeVITcH, ALEXANDER, Ph.D. (Freiburg), Assistant Professor of Zodlogy, Sheffield Scientific School Zodlogical Laboratory, Yale University, New Haven, Conn. Puiturps, Everett Franky, A.B. (Allegheny), Ph.D. (Pennsylvania), Agri- culturalist, Bureau of Entomology, United States Department of Agriculture, Washington, D. C. Prersou, Georce Artuur, M.S. (Pennsylvania), Sc.D. (Pennsylvania College), Professor of Anatomy, University of Pennsylvania, 4724 Chester Avenue, Philadelphia, Pa. 1 250 AMERICAN SOCIETY OF ZOOLOGISTS Pixe, Prank H., A. B., (Indiana) Ph.D. (Chicago), Associate Professor of Physt- ology, Columbia University, 437 West 59th Street, New York City. Powers, Epwin B., Instructor in Zoélogy, University of Nebraska, Lincoln, Neb. Pratt, Henry Suereina, A.B. (Michigan), A.M., Ph.D. (Leipzig), Professor of Biology, Haverford College, Haverford, Pa. Ranp, Hersert Wivpur, A.B. (Allegheny, Harvard), A.M., Ph.D. (Harvard), Associate Professor of Zoélogy, Harvard University, Musou of Compara- tive Zodlogy, Cambridge, Mass. Ransom, Brayron Howarp, B.Se., M.A., Ph.D. (Nebraska), Chief Zodlogical Division, Bureau Animal Industry, United States Department of Agriculture, Bureau of Animal Industry, Washington, D. C. Reep, Huew Daniet, B.S., Ph.D. (Cornell), Professor of Zoélogy, Cornell, McGraw Hall, Ithaca, N. Y. Reese, Atpert Moors, A.B., Ph.D. (Johns Hopkins), Professor of Zoélogy, West Virginia University, Morgantown, W. Va. Rercuarp, JAcop Evtsworru, Ph.B. (Michigan), Professor of Zodlogy, Direc- tor of Zodlogical Laboratory and Biological Station, University of Michigan, Ann Arbor, Michigan. Rernxe, Epwrn Eustace, M.A. (Lehigh), Ph.D. (Princeton), Assistant Professor of Biology, Vanderbilt University, Nashville, Tenn. Rice, Epwarp Loranus, A.B. (Wesleyan), Ph.D. (Munich), Professor of cee ogy, Ohio Wesleyan bar aity; Delaware, Ohio. Ricwarps, A., B.A. (Kansas), M.A. (Wisconsin), Ph.D. (Prineston): Proreses of Zoélogy, Dept. of Zodlogy, Univ. of Oklahoma, Norman, Okla. Ricuarps, Mriprep H., A.B. (Goucher), A.M., Ph.D. (Columbia), Dept. of Zoélogy, Univ. of Oklahoma, Norman, Okla. Rippie, Oscar, A.B. (Indiana), Ph.D. (Chicago), Resident Investigator Car- negie Institution of Washington, Cold Spring Harbor, Long Island, N. Y. Rivey, Witu1AmM Apert, B.S. (Depauw), Ph.3). (Cornell), Professor of Ento- mology, University of Minnesota, University Farm, St. Paul, Minnesota. Rirrer, Wiiuiam E., B.S. (California), Ph.D. (Harvard), Director of Scripps Institution of Biological Research of the University of California, Professor of Zoélogy, University of California, La Jolla, Calif. Roserrs, Eimer, B.S., Ph.D. (University of Illinois), Associate in Genetics, University of Illinois, College of Agriculture, Urbana, /Il. Rosertson, ALBERT Duncan, B.A. (Toronto), Professor and Head of Depart- ment of Biology, Western University, Dept. of Biology, Western University, London, Ont., Canada. Rosertson, Arice, B.S., M.S., Ph.D. (California), Assistant Professor of Zoél- ogy, Wellesley College, Wellesley, Mass. / Ronertson, W. Rees Bresner, A.B. (Kansas), Ph.D. (Harvard), Associate Professor of Zoédlogy, University of Kansas, 1701 Louisiana Street, Lawrence, Kansas. Rogers, Cuartes Garpner, A.B., A.M. (Syracuse), Ph.D. (California), Pro- fessor of Comparative Physiology, Oberlin College, 378 Reamer Place, Ober- lin, Ohio. Rocers, Frep Terry, A.B., Ph.D. (Chicago), Professor of Physiology, Baylor Medical College, Dallas, Texas PROCEEDINGS 251 Roor, Francis Metcatr, A.B., A.M. (Oberlin), Ph.D. (Johns Hopkins), Teach- ing Fellow in Medical Entomology, School of Hygiene and Public Health, Johns Hopkins University, 310-312 West Monument St., Baltimore, Md. Ruruven, Avexanper G., B.S. (Morningside), Ph.D. (Michigan), Director Museum of Zoélogy, Professor of Zoélogy, University of Michigan, Museum of Zoblogy, Ann Arbor, Mich. Scuarrrer, Asa Arruur, A.B. (Franklin and Marshall), Ph.D. (Johns Hopkins), Professor of Zoélogy, University of Tennessee, Knoxville, Tenn. Scurept, Rrewarp C. F., Ph.D. (Pennsylvania), Sc.D. (Hon.) (Franklin and Marshall), Lancaster, Pa. Scorr, Joun W., A.B., A.M. (Missouri), Ph.D. (Chicago), Professor of Zodlogy, Research Parasitologist, University of Wyoming, Laramie, Wyoming. Scorr, Grorce G., A.B., A.M. (Williams), Ph.D. (Columbia), Chairman Depart- ment of Biology, College of the City of New York, New York City. Scorr, Witt, Ph.D. (Indiana), Associate Professor of Zéology, Indiana Uni- versity, Bloomington, Indiana. Suetrorp, Victor Ernest, B.S., Ph.D. (Chicago), Associate Professor of Zoél- ogy, University of Illinois, and Biologist in charge of Research Laboratories, Natural History Survey, The Vivarium, Wright and Healy Sts., Champaign, Illinois. Ssorey, Marian Lypta, A.M., Ph.B. (Brown), Ph.D. (Chicago), Huguenot Col- lege, Wellington, South Africa. Sauti, Aaron FRANKLIN, A.B. (Michigan), Ph.D. (Columbia), Associate Pro- fessor of Zodlogy, University of Michigan, 520 Linden Street, Ann Arbor, Mich. Stcerroos, Cuarues P., B.S. (Ohio State), Ph.D. (Johns Hopkins), Professor of Zoélogy, University of Minnesota, Minneapolis, Minn. SMALLWoop, WiLt1aAM Martin, Ph.D. (Harvard), Professor of Comparative Anat- omy, Syracuse University, 525 Euclid Avenue, Syracuse, N Y. Smitn, Bertram Garner, A.B. (Michigan), Ph.D. (Columbia), Associate Pro- fessor of Zodlogy, Michigan State Normal College, 122 College Place, Y psilanti, Mich. Samira, Exizapets Anita, A.B. (Cincinnati), M.A., Ph.D. (Wisconsin), Assist- ant Professor, University of Wisconsin, Biology Bldg., Madison, Wisconsin. Ssaru, Frank, Ph.B. (Hillsdale College), A.M. (Harvard), Professor of Syste- matic Zodlogy, University of IUinois, Urbana, Ill. Snyper, Tuomas Exxiorr, A.B. (Columbia), M.F. (Yale), Ph.D. (George Wash- ington), Specialist in Forest Entomology, Bureay of Entomology, U. S. Department of Agriculture, Washington, D. C. Srocxarp, CHartes Rupert, B.S., M.S. (Mississippi Agricultural and Mechan- ical College), Ph.D. (Columbia), Professor of Anatomy, Cornell University Medical School, First Avenue and Twenty-eighth Street, New York City. Srreeter, Georce L., A.B. (Union), A.M., M.D. (Columbia), Director of Em- bryology, Carnegie Institution, Johns Hopkins Medical School, Baltimore, Md. SrromsTen, Frank Apert, B.S., M.S. (Iowa), D.Sc. (Princeton), Associate Professor of Animal Biology, State University of Iowa, 943 Iowa Ave., Iowa City, Iowa, 252 AMERICAN SOCIETY OF ZOOLOGISTS Srrone, Outver 8., A.B., A.M. (Princeton), Ph.D. (Columbia), Associate Pro- fessor in Neurology, Columbia University, College of Physicians and Sur- geons, 437 West Fifty-ninth Street, New York City. Srrone, Revsen Myron, A.B. (Oberlin), M.A., Ph.D. (Harvard), Professor of Anatomy, Loyola University School of Medicine, 706 South Lincoln Street, Chicago, Ill. SrurTevant, Autrrep H., A.B., Ph.D. (Columbia), Stanford Univ., Calif. Sumner, Francis B., B. 8. Qiiinnesota), Ph.D. (Columbia), Biologist, Scripps Institution for Biological Research, La Jolla, Calif. Surrack, Frank M., A.B., A.M. (Ohio State), Ph. D. (Pennsylvania), Binlogintl The Washington "Herald, Washington, D. C. Swezy, Ourve, B.S., M.S., Ph.D. (California), Associate in Zoédlogy, Assistant Zodlogist, Scripps Institution for Biological Research, University of Cali- fornia, East Hall, University of California, Berkeley, Calif. Swinecie, Witsur Wiis, A.B., A.M. (Kansas), Ph.D. (Princeton), Instructor in Biology, Sheffield Scientific School, Yale University, Osborn Zoological Laboratory, New Haven, Conn. TauiaFerRO, WitiiaAM Hay, B.S. (University of V rginia), Ph.D. (Johns Hop- kins), Instructor in Protozodlogy, Johns Hopkins University, School of Hygiene and Public Health, 310-312 W. Monument St., Baltimore, Md. TANNREUTHER, GeorGce W., A.B. (Manchester), A.M. (Antioch), Ph.D. (Chi- cago), Instructor in Zodlogy, University of Missouri, Columbia, Mo. Tasurro, Sarro, B.S., Ph.D. (Chicago), Associate Professor of Biological Chem- istry, University of Cincinnati, College of Medicine, Cincinnati, Ohio. Taytor, Cartes Vincent, Ph.D. (California), Assistant Professor of Zoélogy, University of California, East Hall, University of California, Berkeley, Calif. TENNENT, Davip Hirt, B.S. (Olivet), Ph.D. (Johns Hopkins), Professor of Biol- ogy, Bryn Mawr College, Bryn Mawr, Pa. Tompson, CAROLINE Burtwina, 8.B., Ph.D. (Pennsylvania), Associate Profes- sor of Zoédlogy, Wellesley College, Wellesley, Mass. Torrey, Harry Brat, B.S., M.S. (California), Ph.D. (Columbia), Professor of Zoblogy, University of Oregon, Eugene, Ore. TREADWELL, AARON L., B.S., M.S. (Wesleyan), Ph.D. (Chicago), Professor of Biology, Vassar College, Poughkeepsie, N.Y. TurNER, CLARENCE Lester, A.B., A.M. (Ohio Wesleyan), Ph.D. (Wisconsin), Professor of Zoélogy, Beloit College, Beloit, Wisconsin. Van Creave, Harvey Jones, B.S. (Knox College), M.S., Ph.D. (Illinois), Assist- ant Professor of Zoédlogy, 300 Natural History Building, University of Illinois, Urbana, Ill. Waaner, Georoe, B.A. (Kansas), M.A. (Michigan), Associate Professor of Zoél- ogy, University of Wisconsin, Biology Building, Madison, Wis. ; Waite, Freperick Cayton, Litt.B. (Adelbert), A.M. (Western Reserve), A.M., Ph.D. (Harvard), Professor of Histology and Embryology, School-of Medi- cine, Western Reserve University, 1353 East 9th Street, Cleveland, Ohio. Water, Hersert Evcene, A.B. (Bates), A.M. (Brown), Ph.D. (Harvard), Associate Professor of Biology, Brown University, Providence, R. I. PROCEEDINGS 253 Warp, Henry Batpwin, A.B. (Williams), A.M., Ph.D. (Harvard), Professor of Zodlogy, University of Illinois, Urbana, Illinois. Wetcn, Pauw Smitn, A.B. (James Millikin), A.M., Ph.D. (Illinois), Assistant Professor of Zoélogy, University of Michigan, Ann Arbor, Mich. Weese, Asa Orrin, A.B. (Minnesota), A.M. (Illinois), Professor of Biology, University of New Mexico, Secretary, Ecological Society of America, Albu- querque, N. Mex. Wetts, Morris Mituer, B.S. (Chicago), Ph.D. (Illinois), President General Biological Supply Co., 5408 Kimbark Ave., Chicago, Ill. Wenricu, Davin Henry, B.A., M.A., Ph.D., Instructor in Zodlogy, University of Pennsylvania, Zodlogical Laboratory, Philadelphia, Pa. Wentworth, Epwarp N., M.S. (Iowa), Professor of Animal Husbandry, Kan- sas State Agricultural College, Manhattan, Kan. WHeE.ER, W1tt1AM Morton, Ph.D. (Clark), Professor of Economie Entomol- ogy, Bussey Institution, Forest Hills, Boston, Mass. Wuire, Gertrupe Marean, B.A. (Milwaukee-Downer), M.A., Ph.D.(Wisconsin), Instructor in Biology, Margaret Morrison Division, Carnegie Institute of Technology, Pittsburgh, Pa. WuitTtnG, Purneas W., A.B., M.S., Ph.D., Professor of Biology, St. Stephen’s College, Annandale-on-Hudson, N.Y. Wauirney, Davin Day, B.A. (Wesleyan), M.A., Ph.D. (Columbia), Professor of Zoblogy, University of Nebraska, Lincoln, Neb. Wireman, Harry Lewis, A.B., A.M. (Cincinnati), Ph.D. (Chicago), Professor of Zoélogy, University of Cincinnati, Cincinnati, Ohio. Witper, Harris Hawrnorne, A.B. (Amherst), Ph.D. (Freiburg), Professor of Zoblogy, Smith College, Northampton, Mass. Witper, Inez Wurrrte, Ph.B. (Brown), M.A. (Smith), Associate Professor of Zodlogy, Smith College, 27 Belmont Ave., Northampton, Mass. Wiupman, Epwarp E., B.S., M.S., Ph.D. (Pennsylvania), Head Department of Science, West Philadelphia High School for Girls, Instructor in Zodlogy, University of Pennsylvania, 4331 Osage Avenue, Philadelphia, Pa. Wrxarp, W. A., Ph.B. (Grinnell), A.M. (Tufts and Harvard), Ph.D. (Harvard), Professor of Anatomy, University of Nebraska, College of Medicine, Omaha, Neb. WI iiams, SterHEeN Riaos, A.B., A.M. (Oberlin), A.M., Ph.D. (Harvard), Pro- fessor of Zodlogy and Geology, Miami University, 300 East Church Street, Oxford, Ohio. Witson, Epmunp B., Ph.B. (Yale), Ph.D. (Johns Hopkins), LL.D. (Yale, Chi- cago, Hopkins), M.D. (Hon.) (Leipzig), Se.D. (Cambridge), Da Costa Pro- fessor of Zodlogy, Columbia University, New York City. Witson, Henry Van Perers, A.B., Ph.D. (Johns Hopkins), Professor of Zodél- ogy, University of North Carolina, Chapel Hill, N. C. WopsepALexk, Jerry Epwarp, Ph.B., M. Ph., Ph.D. (Wisconsin), Professor of Zodlogy and Head of the Department of Zodlogy and Entomology, Univer- silty of Idaho, Moscow, Idaho. Wotcort, Ropert Henry, B.S., M.D. (Michigan), A.M. (Nebraska), Professor and Head of the Department of Zodlogy, University of Nebraska, Lincoln, Neb. 254 AMERICAN SOCIETY OF ZOOLOGISTS Wooprvrr, Loranpe Loss, A.B.,; A.M., Ph.D. (Columbia), M.A. (Yale), Pro- fessor of Biology, Yale University, Osborn Zodlogical Laboratory, New Haven, Conn. Wricut, Atpert Hazen, A.B., A.M., Ph.D. (Cornell), Assistant Professor of Zoblogy, Cornell University, Upland Road, Cayuga Hts., Ithaca, N. Y. Wricut, Sewaut G., 8.B. (Lombard), 8.M. (Illinois), Sc.D. (Harvard), Senior in Animal Breeding Investigation, Animal Husbandry Division, Bureau of Animal Industry, Department of Agriculture, Washington, D. C. Yerkes, Ropert M., Ph.D. (Harvard), Professor of Psychology, University of Minnesota, Chairman Research Information Service, National Research Council, 1701 Massachusetts Ave., Washington, D. C. Yocum, H. B., A.B. (Oberlin), M.A., Ph.D. (California), Assistant Professor of Zodlogy, University of Oregon, Eugene, Ore. Yosuipa, Sapao, D.Sc. (Tokyo Imperial University), Professor of Parasitology and General Zoélogy in Osaka Medical College, Japan. Home address, Osaka Medical College, Osaka, Japan. Youna, Rosert T., B.S. (Pennsylvania), Ph.D. (Nebraska), Professor of Zoél- ogy, University of North Dakota, University, North Dakota. ZeLENY, CHarues, Ph.D. (Chicago), Professor of Zoélogy, University of Illinois, Urhana. Tllinots. THE ANATOMICAL RECORD, VOL, 20, No. 3, FepRvuarr, 1921 Resumen por el autor, Juan C. Nanages, Universidad de Filipinas. Dos casos de coraz6n monoventricular con atresia y transposicién de algunas de las raices de los grandes vasos. En 118 corazones de ninos filipinos, estudiados por el autor con referencia al orificio oval (foramen ovale) se hallaron dos corazones monoventriculares. La presente contribucién pre- senta una descripeién morfolégica de estos dos casos de coraz6n monoventricular, encontrados en dos varones, uno de ellos de dos horas, el otro de cuatro dias de edad. En el primer caso se comprobé la existencia de un ventriculo derecho sumamente pequeno, con el tabique interventricular desplazado y el orificio atrio- ventricular derecho ocluido. En el segundo caso se noté la existencia de un tabique interventricular incompleto, acom- panado de ausencia completa del orificio mitral. El autor discute ambos corazones con relacién a su probable desarrollo y fisiologia. Los casos de coraz6n monoventricular son com- patibles con el desarrollo intraruterino normal, pero cuando estén asociados con estenosis pulmonar, atin en el caso de existir un conducto arterial patente, la vida puede mantenerse tan solo durante unas pocas horas después del nacimiento. Translation by José F. Nonidez Cornell Medical College, New York AUTHOR'S ABSTRACT OF THIS PAPER I88U ED BY THE BIBLIOGRAPHIC SERVICE, DECEMBERO TWO CASES OF MONOVENTRICULAR HEART WITH ATRESIA AND TRANSPOSITION OF SOME OF THE ROOTS OF THE GREAT VESSELS JUAN C, NANAGAS Department of Anatomy, University of the Philippines EIGHT FIGURES (TWO PLATES) In the course of a series of examinations that the writer under- took on a collection of Filipino infant hearts, for the special study of the foramen ovale, he encountered among 118 two instances of peculiar abnormalities that were thought of sufficient interest not only from the embryological viewpoint, but also from their physiological importance in relation to the viability of the fetus, as to warrant this brief descriptive report. Congenital malformations of the heart do not usually interest many readers of medical literature, for the reason that they are often classed as ‘“‘mere developmental curiosities of the human organism” devoid of special clinical significance to the general practitioner. Though this may be true to a certain extent in the two cases that I am now reporting, nevertheless, it must be borne in mind that some of these instances of defective cardiac development are quite compatible with life, and are of sufficiently common occurrence as to render their recognition not only important, but even essential to clinical medical men. Cases have been recorded where individuals have lived for years with cardiac malformations. In life, these patients must have undoubtedly exhibited definite but undiagnosed clinical pictures, which could have been recognized and a more rational treatment prescribed had their clinical consideration been carried in con- junction with corresponding anatomical and physiological studies. Gladstone, in his paper on cardiac malformations, emphasizes particularly this point when among other things he stated: 255 256 JUAN C. NANAGAS It is of greatest importance that the signs and symptoms produced by these different types of cardiac malformation should be carefully studied in all cases and recorded, so that an opportunity will be afforded of comparing one case with another, and of diagnosing the kind of abnormalities during life. In order to complete our knowledge of these cases, however, it remains for clinicians to correlate the signs and symp- toms which these different malformations of the heart produce. It will then be possible to recognize the type of malformation during the patient’s lifetime, and to carry out the treatment of individual patients upon a rational basis. It is intended to present in this paper, first, the anatomical conditions of the abnormalities found in each case, and then to - offer a tentative explanation of their possible embryological origin and the probable cardiac circulations occurring during intra and extra vane life. ANATOMICAL FINDINGS Case 1. The first specimen was the heart of a male Filipino infant that lived only two hours after birth. The case came to the city morgue from one of the health districts of the city, and for this reason no clinical history could be obtained except that the baby lived for about two hours. In opening the heart by routinary incisions I was surprised to observe that there were only three cardiac chambers, viz., the right and left auricles and a considerably enlarged ventricle. External examination showed that what should have been considered at a glance as the trunk of the pulmonary artery, with its prominent anterior position and left upward course, was really the ascending root of the aorta with its wide communication to the single ventricle. The real pulmonary artery was found only after a careful search, as a small poorly developed vessel on the left anterior side of the aortic trunk closely adherent to it, and apparently, from the outside at least, continuous with the base of the ventricle (fig. 1, Band C). The great cardiac vein together with the anterior coronary artery, that normally course downward to the apical notch of the heart, were considerably shifted to the right of the median line running obliquely to the right border of the ventricle (fig. 1, A). TWO CASES OF MONOVENTRICULAR HEART 257 This heart weighed 17.2 grams, or 0.81 per cent of the body weight, the latter being 2,114 grams. Its greatest circumference taken at the base of the ventricle was 96 mm. and its longest diameters were 46 mm. vertically, 37 mm. transversely, and 21 mm. anteroposteriorly. The ratio of the weight of the heart to the body weight in this case is a trifle greater than the normal ratio as given by Jackson (0.77 per cent) and Vierordt (0.76 per cent) in newly born infants. The difference of 0.04 to 0.05 per cent is in reality sufficiently small to warrant the conclusion that this heart, at least in weight, has attained its normal state of development. . On. careful internal examination of the single ventricle no trace could be seen of the existence of any separation of this chamber into right and left halves. The right lateral wall, however, showed a marked thickening of the cardiac musculature, which extended medially, as far as a line coinciding externally, with the oblique course of the anterior coronary artery described above (figs. 2 and 3). An anteroposterior cut through the thick- ness of this part of the wall showed the muscle fibers in close relation anteriorly and superiorly with the rudimentary trunk of the pulmonary artery, from which point they appeared to stream obliquely downward and posteriorly. The excessive thickness of this part has produced a corresponding internal swelling into the cavity of the ventricle at its right lateral side. This fact would seem to indicate that this internal swelling probably represented the rudiment of an interventricular septum which might have become arrested in its development. The single ventricle in this heart therefore is in reality the left ventricle which had become compensatingly enlarged. In the cavity of the ventricle there were found two large and several small papillary muscles and many trabeculae carnae (figs. 2 and 3). The principal papillary muscles were normal in location for the left ventricle, one of them arising from the left anterior wall and the other from the posterior wall. The cordae tendinae from these papillary muscles extended to the medial angles of the anterior and posterior cusps of the mitral valve and were attached to their margins. 258 JUAN C. NANAGAS The circumference of the left auriculoventricular orifice in this case was 35.5 mm. From cardiac measurements of ninety-- six still-born infants made by me I had obtained a normal average of 24.5 mm. for the circumference of this opening. It seems, therefore, that the excess of 11 mm. would be accounted for by the fact that this orifice’s being the only communication between the auricles and the ventricle it had probably become compen- satingly enlarged. The other communication that the single ventricle had was with the aorta. The circumference of this aortic orifice measured 16.5 mm., a little more than my normal average figure, which was 14 mm. This opening was guarded by three semilunar cusps, two anterior, slightly shifted to the left in the direction of the pulmonary artery, and one posterior. Each of these cusps showed well-developed sinuses, from two of which the right and left coronary arteries originated as in normal cases. The vessel leading from the ventricle through this orifice, though from its external position would correspond to the pulmonary artery, is nevertheless undoubtedly the aorta because of the facts above considered, viz., the position of the guarding semilunar valves and the origin of the coronary arteries and because of the greater thickness of its wall. The right auriculoventricular orifice examined from the auricular side is oval in shape with its long axis directed trans- versely and its cireumference measuring approximately 17 mm. Its margins are sharply defined and the flaps of the valve were completely fused together forming a 7-mm. pit underneath the orifice. Several small openings were found at the bottom of this pit which on a sagittal section showed them to open into blind crevices lodged in the right thickened part of the ventricular wall (figs. 2 and 3, C). This fact seems to further confirm the statement that the medial portion of this thickened wall repre- sented a rudimentary interventricular septum. The crevices into which the openings of the flaps led were probably the remains of an imperfeetly developed right ventricle, which conclusion is still more justified by the organic connection of the fibers of the ventric- ular wall in this neighborhood and the roof of the obliterated TWO CASES OF MONOVENTRICULAR HEART 259 pulmonary artery as previously recorded. The bundles of fibers found between these crevices were possibly diminutive papil- lary muscles. The imperfectly developed trunk of the pulmonary artery was only about one-fifth the size of that of the aorta and was partly hidden from view by the left auricular appendix. On opening the artery proximally it was found to terminate blindly in three small sinuses which did not appear to have any con- nection with either the ventricle or the crevices found beneath the occluded right auriculoventricular orifice. Two of these sinuses were posterior and slightly medial in position, while the other was anterior. They were limited by three embryonic semilunar valves fused together and exhibiting thickened borders at the lines of fusion. Below this level the ventricular wall appeared on section to be entirely solid; the infundibulum or conus arteriosus was therefore entirely arrested in its formation. From the right posterior wall of the pulmonary artery about 2 em. from its root arose the patent ductus arteriosus, which was about as large as the pulmonary trunk itself and established a free communication with the ascending aorta (fig. 1). The foramen ovale was patent, the aperture between the free edges of the independent septum primum and septum secundum measured 4sq.mm. The septum primum, however, was greatly relaxed, bulging considerably into the left atrium. This con- dition was possibly due to the irremediable free flow of blood from the right-to the left sides of the heart. Case 2. This heart was that of a poorly nourished full-term male Filipino baby that lived only four days postpartum. It showed harelip and polydactilism of both hands. Its body weight was 1,640 grams, sitting height 30 cm. and standing height 46 em. It will be noticed that the body weight in this case was far below the average given for normal newly born European and American babies as given by various investigators (over 3,000 grams) and a little below the average obtained by me for appar- ently normal Filipino still-born babies (2,200 grams). 260 JUAN C. NANAGAS Its standing height was only a trifle below the average figures given for American and European still-born babies, which was about 49 em. The differences of these two measurements from the normal averages would seem to indicate that while the development of the body was about normal, it was undoubtedly ill nourished. From the shape of the heart alone one would readily anticipate the presence of some abnormalities. The vertical diameter was markedly in excess to the width. It weighed 17.7 grams, or 1.07 per cent of the body weight. This ratio was higher than in our first case and considerably greater than the figures given by Jackson and Vierordt. The greatest circumference of this heart was 92 mm., the largest vertical diameter was 47 mm., the transverse 36 mm., and the anteroposterior 26 mm. The anterior surface represented by the anterior half of the right atrium and the ventricle was massive and much larger than the posterior surface. It was divided into a larger triangular right anterior facies and a narrower roughly quadrangular surface at the left by a linear elevation of the ventricular wall running from the base above to the apex of the ventricle below. The wall of the ventricle at the upper end of this right anterior portion was elevated in a marked upward prominence consider- ably deepening the auriculoventricular sulcus at this point (fig. 4). The conus arteriosus was entirely absent and the pulmonary artery could not be seen on the normal point of its origin from the ventricles. The only vessel seen originating directly from the latter was the aorta, which appeared much larger than nor- mal, and its ascending portion showed a funnel-shaped enlarge- ment as it approached the arch. In position this vessel was shifted considerably to the left, arising from the upper third of the left ventricular border at a point considerably below the auriculoventricular sulcus. Unlike the ordinary condition, the aorta in this case followed an upward course, inclining immedi- ately to the left so that its ascending portion was directly on the left upper ventricular wall, and only the arch came into relation with the left side of the atrium. The tip of the auricular appen- dix was barely touching the arch at its beginning. TWO CASES OF MONOVENTRICULAR HEART 261 On opening the right atrium by an incision following its greatest superior curvature, it was found to consist of an apparently dilated cavity into which three openings were found, two at its posterior wall corresponding to the superior and inferior venae cavae, and one found inferiorly leading into the ventricle, the auriculoventricular orifice. ; On examining the posterior wall of this atrium from the out- side, four smaller vessels, presumably the four pulmonary veins, were seen, which, however, did not directly open into the large cavity described above, but into a small flattened space adjoining the posterior atrial wall, which undoubtedly represented a rudi- mentary left atrium. ‘This cleft-like space was separated from the enlarged right auricle by an interatrial septum in which an oval opening guarded by a thin septum was seen. This opening which was the foramen ovale appeared normal in every respect. No communication between the left auricle and the ventricle was found. The only communication, therefore, between the ventricle and the atrial portion of this heart was represented by the right auriculoventricular orifice, which measured approxi- mately 42 mm. in circumference. Internally the ventricular portion of this heart showed only a single vertically elongated cavity, in which no recognizable division between a right and a left portion could be found. There was, however, a more or less prominent ridge situated in the middle of the posterior wall of the cavity, which by its position could be considered as representing the septum interventriculare (figs. 5 and 6). If such were the case, then this heart would have undivided right and left ventricles in their embryological con- dition, closely resembling in this manner the amphibian type of heart. The right portion of this ventricular cavity was in direct communication with the single enlarged atrium. The left side was continued upward and posteriorly to form the root of the aorta, while anterosuperiorly it gradually merged with a small elongated blind space found inside the peculiarly bulging portion of the anterior surface of the base of the ventricle (fig. 4). The ventricular wall as a whole was massive, averaging about 6 mm. in thickness. Two small papillary muscles were present, 262 JUAN C. NANAGAS one situated in front and the other posteriorly, with their cordae tendinae attached to the edges of the flaps of the single auriculo- ventricular orifice. This opening possessed but two flaps, differ- ing in this respect from the normal, which has three. The aortic opening, as in normal hearts, was guarded by three semilunar cusps, two found anteriorly and one posteriorly. The three aortic sinuses (sinuses of Valsalva), were found to be dipping down into the wall of the ventricle to a much greater extent than in normal cases. The ascending aorta, as noted above, was funnel-shaped and joined the aortic arch upward posteriorly. The latter was likewise fairly dilated. Only the right coronary artery originated from the right aortic sinus. It coursed downward in a zigzag direction for a short distance in the posterior coronary suleus, which it soon left to run along the posterior or diaphragmatic surface of the heart, curving toward the left border considerably above the apex, and anastomosing at this point in a plexiform manner with the anterior descending branch of the left vessel. The left coronary arose directly from the anterior wall of the ascend- ing aorta. On reaching the level of the root of this vessel in its descent, it followed forward and to the right, the anterior coronary sulcus under cover of the right auricle until it reached its extreme right end; thence the artery coursed along the right ventricular margin as far as the apex, where it resolved into plexiform anastomoses. Another striking anomaly found in connection with the aorta was the presence of two fairly good-sized branches originating from its posterior wall about half a centimeter from its proximal end, These vessels were found to correspond with the right and left pulmonary arteries, the common pulmonary trunk being absent. This peculiar condition was not noticed until after the removal of the heart, and the identification of these two vessels was based upon a careful search and topographic comparison of their cut cardiac and pulmonary ends. The diameters of these two vessels were approximately 4 mm. for the right and 3mm. for the left. TWO CASES OF MONOVENTRICULAR HEART 263 REVIEW OF LITERATURE In reviewing the literature at our command for cases showing similar cardiac malformations, we found the following: 1. Three-chambered hearts. Keith (’09), in his extensive review of 272 cases, established three types of three-chambered hearts, viz., a) hearts in which the interventricular septum was so little developed, or in which the interventricular foramen was so large that the two ventricles were rightly said to form one chamber; b) those cases where the right ventricle was suppressed by the septum’s being applied to the right side of the heart, and, c) those in which the left ventricle was suppressed by the interventricular septum closely shifted to the left ventricle wall of the ventricle. He found in his set nine cases belonging to the first type with associated arterial transpositions; seven cases to the second type, five of which showed complete obliteration of the right ventricle and two with the two ventricles forming a common chamber, and in every case the infundibulum was well developed. Of the third type he found five cases. In the second and third groups the absence of a ventricle was associated with a complete or almost complete obliteration of the corresponding auriculo- ventricular orifice. Young (’07) and Dixon Mann (’07) reported a case of an adult man aged 35 years whose heart showed complete absence of the septum interventriculare with associated transposition of the arterial trunks. Paterson (’08—’09) reported a similar cardiac malformation in a man 22 years old. Both cases belong properly to the second type. Gladstone (’15—16) cited two cases of this cardiac anomaly, one from a child 48 hours old where the left ventricle was rudi- mentary and functionless and which therefore would fall under group 38, and the other case, a woman 50 years of age with a heart showing a patent foramen interventriculare with constric- tion of the ostium bulbi; which could be included under type 1. Dickson and Frazer (713) had a ease in a male child 3 months old. The specimen showed a hypertrophy of both ventricles 264 JUAN C. NANAGAS with incomplete development of the interventricular septum. This instance could be included in the first type. It was asso ciated with an abnormal origin of the pulmonary artery. Keith (12) mentioned four other cases where the interven- tricular foramen showed varying degrees of patency found in individuals from 9 months to 16 years of age, associated with such anomalies as closure of the auriculoventricular orifice, undeveloped ventricle, and closure of the pulmonary orifice, ete. Three of these cases properly belonged to the first type, but one case, with undeveloped condition of the right ventricle, could also be considered as belonging to type 2. He also cited a case of a child 48 hours old where the heart showed obliteration of the left ventricle and the corresponding auriculoventricular orifice. This case of course belonged to type 3. Black (’13-14) reported two cases: one heart, belonging to an adult male 22 years of age, showed a large interventricular foramen with associated malformations of the pulmonary cusps; the other was that of a male child 6 months old with a patent foramen interventriculare and a marked reduction of the size of the aorta with no associated anomaly of the infundibulum. These two might rightly be included under type 1. Our first case belongs to type 2, as it shows a diminutive right ventricle with the interventricular septum shifted to the right side. The second case that had an incomplete septum is to be included in type 1 of Keith’s classification. In case 1 there was a complete obliteration of the right auriculoventricular orifice from fusion of the flaps. Case 2 showed a complete absence of the mitral opening. 2. Arrest in the developmental expansion of the infundibulum. Keith (09) encountered thirty-seven cases of such condition. The typical picture of such cases had the infundibulum reduced to a mere slit situated at the orifice of the pulmonary artery - which was generally represented by a small cicatricial mass, or a very small lumen in which the fused semilunar valves could be distinguished. The pulmonary artery was in the majority of cases represented by a fibrous cord at its origin. TWO CASES OF MONOVENTRICULAR HEART 265 In the case of Dickson and Fraser (’13) the right pulmonary artery originated from a point 4 inch above the commencement of the ascending aorta and the left from the descending portion. Keith (12) mentioned a case in a male child 11 months old where the infundibulum was obliterated and the pulmonary artery received blood from the ductus arteriosus. Peterson’s ('08-’09) case showed besides, a marked stenosis of the pulmonary orifice with a substitution of the pulmonary valves by a thick pad of cardiac tissue. In our eases, the first showed the pulmonary arterial trunk markedly reduced in size and the pulmonary orifice entirely closed from fusion of the semilunar flaps. In the second case the pulmonary trunk was entirely absent, and the two small arterial vessels identified as the pulmonary arteries were seen arising from the posterior side of the aorta. 8. Atrophy of the auricular portion of the heart. Keith (’09) met three cases which showed considerable diminution in the size of the left auricle associated with complete stenosis of the mitral orifice. He stated that such cases might easily have escaped detection and could have been considered as two- chambered hearts—a rare condition which, even with his wide experience on the subject, he had never yet seen. Our second case shows undeveloped left atrium together with _ absence of the left auriculoventricular orifice. 4. Incomplete separation of the aorta and pulmonary artery. Trregularities in the division of the truncus arteriosus, which becomes divided to form the root of the aorta and the pulmonary artery, according to Keith, are rare. He had only seen three cases in his series. Rakitansky reported a case with this con- dition, but. with the pulmonary artery considerably larger than that found in our case. Our second case showed incomplete separation of the pulmo- nary artery from the ascending aorta and two small vessels repre- senting the pulmonary arteries arising directly from the posterior side of the beginning of the aortic root, which in turn was con- siderably shifted to the left side of the heart. 266 JUAN C. NANAGAS EMBRYOLOGICAL CONSIDERATIONS Owing to the various possibilities which could be considered in our eases, it would seem rather difficult to definitely offer any explanation that would adequately cover the different embryological factors which might have led to the production of the anomalies herein enumerated. 1. Monoventricular condition. In our first case we encountered a suppression of the right ventricle by the septum’s being applied to the right side of the heart. In the second case the two ven- tricles were imperfectly separated by defects in the interven- tricular septum. We have failed to find in our search of the literature any author who endeavored to explain the first condition. It is a well-known fact that at some stage of the normal develop- ment of the heart there is a time when the so-called ventricular limb starts its division into a greater left and a smaller right half, to be later known as the left and right ventricles, respec- tively, by the production on its external convex surface of a groove and within its cavity of an interventricular septum. If at this period of development by some unknown reason the normal proportionate development of parts were arrested or at least changed to an unequal growth, similar anomalies would probably result. Thus if we were to suppose at this stage - a delayed or even an arrested growth of the right side of the heart, with consequent continued and relatively increased devel- opment of the left, a condition would result where the left cardiac cavity would appear greatly enlarged, with the septum apparently reduced to a mere parietal thickening shifted well to the right, and the right ventricular cavity represented by mere crevices or by a diminutive cavity hardly large enough to permit the unfolding of the tricuspid valves. This condition is exactly similar to that encountered in our first specimen. Our second case of monoventricular heart with imperfect separation of the two ventricles by defect in the interventricular septum has been encountered and explained by several writers on this subject. Gladstone explains the persistence of the inter- TWO CASES OF MONOVENTRICULAR HEART 267 ventricular foramen as an apparently secondary condition to the failure in the expansion of the bulbar portion of the right ven- tricle, and says that its presence and size depend largely upon the extent of the defect. Hunter and Keith hold the same view, i.e., that the interventricular foramen is produced by the obstruc- tion or stenosis of the pulmonary artery and that the closure of the interventricular foramen depends on the complete develop- ment of the infundibulum. Keith further states that from 85 to 90 per cent of the cases with pulmonary stenosis showed an interventricular foramen. Meckel, as cited by Keith (’09), claimed, on the other hand, that the interventricular foramen is a primary condition and the pulmonary stenosis its sequence. Young asserts that the course of the main blood-stream inside of the heart could interfere with the complete development of the interventricular septum. The monoventricular condition in our second case may be explained perhaps by an arrest of growth of the interventricular septum, which in this case is represented by a mere ridge in the ventricular floor. This septal condition is similar to its early stage of development in the division of the embryonic ventricle into two halves. This arrest is undoubtedly due to the mechani- cal pressure and friction exerted upon it by the flow of blood coming through the right auriculoventricular orifice and which not finding any exit at the right ventricular side because of the total absence of a pulmonary artery is forced toward the left side of the ventricle to find there its only orifice of escape repre- sented by the aorta (fig. 8). The abnormal and excessive upward prominence of the ven- tricular wall in its anterosuperior base must also be looked upon as a necessary result of the same continued increased pressure exerted upon that part of the ventricle by the blood-stream passing through the aortic orifice. This influence is certainly conceivable, if we remember that the arterial pulmonary trunk should have taken origin from this region, and that the tender ‘embryonic cardiac musculature is very apt to give way to such a persistent and continued mechanical factor. 268 JUAN C. NANAGAS 2. Congenital stenosis of the pulmonary orifice with or without arrest of the developmental expansion of the infundibulum. Keith explains the majority of those cases of congenital pulmonary stenosis associated with arrested development of the infundib- ulum as due to a failure of the bulbus cordis to incorporate with the right ventricle. In those cases where the stenosis is not, however, associated with an arrested infundibulum, he believes foetal endocarditis to be responsible for the defect. In this connection we quote from Gladstone the following: According to Schipman, the most common and important effect of intra-uterine endocarditis is stenosis of the pulmonary orifice, and he also states that the limitation of the endocarditis to the right side of the organ during intra-uterine life comes under the same law as its limitation to the left side in extra-uterine life. In both cases it is the cavity which has most work to perform that is affected. According to this view, cases in which the interventricular foramen has not persisted are produced by endocarditis occurring after the period when this fora- men is normally closed. The closure is effected by the fusion of the interventricular septum with the bulbar septum, and this takes place in embryos between 12 mm. and 18 mm. in length, and at the age of six or seven weeks. It is possible, however, that the endocarditis is a secondary incident which has occurred after birth, and that the pri- mary condition is constriction. It is probable also that the constric- tion is attributable to a primary defect in development rather than to a foetal endocarditis; for if foetal endocarditis were the cause, we should expect also to find stenosis of the right auriculo-ventricular orifice with endocarditis of the tricuspid valve, but this is not found, on the contrary congenital stenosis of the right auriculo-ventricular orifice is extremely rare. In our two cases we found a complete absence of the infundib- ulum, associated in the first case with a diminutive pulmonary artery and stenosis of the pulmonary orifice by fusion of its similunar valves and with complete absence of the pulmonary artery and pulmonary orifice in the second. These defects plus the absence of any inflammatory signs in the perfectly smooth and shiny fused pulmonary flaps incline us to believe that neither foetal endocarditis nor the failure of incorporation of the bulb into the night ventricle would furnish , satisfactory explanations. TWO CASES OF MONOVENTRICULAR HEART 269 In normal cases we know that the separation of the bulb into the aortic and pulmonary trunks is the result of the fusion of the right and left distal bulbar swellings and the septum aorto- pulmonale. These swellings are linear thickenings of the endo- cardial surface of the bulb, two at its proximal and four at the distal portion. The union of the right and left distal bulbar swellings is generally produced by the ingrowth of the con- nective tissue of the bulbar wall. This fusion together with the approaching septum aortopulmonale brings about the com- plete division of the bulbar trunk into a ventral vessel, the aorta and a dorsal pulmonary artery. The two proximal swellings by their spiral direction complete further this division by bringing each vessel into a more direct relation with its corresponding ventricle. The semilunar valves of the aortic trunk are formed by the anterior distal bulbar swelling and the two anterior halves of the right and left laterally. Those of the pulmonary artery by the posterior and the posterior halves of the right and left distal lateral swellings. Now it is possible that in the first case, owing to inequality in growth of the ventricle, the union of the right and left bulbar swellings with the septum aortopulmonale has taken place, but considerably shifted to the anterior side of the bulb. This shifting has necessarily reduced the pulmonary artery to a diminutive trunk, and its semilunar valves, remaining diminutive and crowded together, have become completely fused. In the second case the septum aortopulmonale has probably failed to descend and meet the bulbar swellings, leaving in this manner the truncus arteriosus undivided, and the pulmonary arteries arising directly from the ascending aorta. Such con- dition would also account for the absence of the pulmonary orifice. 8. Rudimentary and collapsed condition of the left auricle. As regards the rudimentary. and collapsed state of the left atrium and the absence of its atrioventricular orifice, it does not seem possible to offer as reasonable explanations as in the anomalies already considered above, we might, however, conceive such abnormality as due to a probable combination of such two factors as: 270 JUAN C. NANAGAS a. A possible arrest or entire failure of development of the two endocardial cushions which should normally appear in the ventral and dorsal walls of the heart in the region of the atrio- ventricular sulcus, together with fusion of this sulcus with the interatrial septum in the side of the left atrium. b. Normally developed cushions which after their union were shifted to the left to meet and fuse with the atrioventricular suleus in this side. This condition, if combined with an arrest of further development of the left atrium with a compensatory enlargement of the right side, would give rise to a condition similar to that found in our specimen. Such a combination of factors influencing the production of the above abnormalities could only be made possible by the total absence or diminished amount of blood flowing into the left atrium as a result of the absence of the arterial pulmonary trunk. The four pulmonary veins probably transmitted little blood if any at all into the left atrium, two vessels which were taken as representing the pulmonary arteries being altogether too small to carry on any appreciable pulmonary circulation. PHYSIOLOGICAL CONSIDERATIONS Probable cardiac circulation in the two cases. A morphological study of the circulation, both during the intra-uterine and post- partum lives, in both cases would indeed be of some interest. Case 1. Prenatal circulation in this case is obviously possible and could normally be carried on to full term without greatly impairing the normal general development of the foetus. The arterialized blood from the placenta undoubtedly followed a normal cireuit by passing successively through the right and left atria (freely communicating with each other by a patent and relaxed foramen ovale), to the single ventricle through the widely open mitral orifice, and thence to the general circulation, passing out of the aortic root. A satisfactory explanation of the postpartum circulation in this case would offer several difficulties. Literatures on cardiac malformations mention only a few instances where three-cham- TWO CASES OF MONOVENTRICULAR HEART 271 bered hearts were found in adult individuals. Cases with complete atresia of the pulmonary orifice, as in the case under consideration, have never been known to live for more than twenty-four hours. In such instances where a complete arrest of the infundibulum was present, the lungs, according to Professor Keith, were supplied with blood from the systemic circulation through the bronchial arteries and other accessory branches of the intercostals. It is unfortunate that we were unable to obtain a complete clinical history of our case; this would prob- ably have helped us in our explanation by knowing the behavior of the child after delivery. It is of course possible to conceive that the pulmonary circu- lation could be carried in one of the two following ways: a. The lungs may receive some blood via the bronchial arteries and intercostal branches, as explained by Professor Keith. We regret that we were unable to study the bronchial arteries of this specimen. We question, however, the ability of such circu- lation to sustain life for any length of time in our case because of the almost complete absence of any expanded lung tissue in either side. The child lived only two hours. b. Pulmonary circulation might be possible also by the blood passing successively from the right auricle to the left atrium through the foramen ovale, thence to the left ventricle through the mitral orifice, therefrom into the aorta from which a small amount of blood could enter the ductus arteriosus in the reverse direction and eventually reach the lungs via the pulmonary artery (figs. A and B). The great downward obliquity of the ductus arteriosus in its union with the aorta, its relatively small size, and the reverse direction of the collateral stream incline us to believe that only a small amount of blood, if any at all, could possibly reach the lungs by this route. If we add further to the above facts, the venous condition of the blood thus circulating, we almost wonder how the child could have lived even for two hours as it did, unless the oxygenation of its blood from the placenta could have carried him through that length of time. Case 2. The foetal circulation in utero in this case undoubtedly followed a similar route as in case 1, 2/2 JUAN C. NANAGAS The postpartum circulation offers to a certain extent similar difficulties as those encountered in case 1. The pulmonary circulation was carried on again either by the collateral bronchopulmonary circuit of Professor Keith or through the two diminutive pulmonary arteries branching off from the aorta. In either case, however, the return circulation took place through the four diminutive pulmonary veins into the collapsed left atrium and thence through the foramen ovale into the right auricle, completing in this manner the pulmonary circuit. A B Fig. A Diagrammatic sketch showing probable circulation in ease 1. Fig. B Diagrammatic sketch showing probable circulation in case 2. IVC, inferior vena cava; RA, right atrium; LA, left atrium, SVC, superior vena cava; A, aorta; DA, ductus arteriosus; PA, pulmonary arteries; PV, pul- monary veins; LV, left ventricle; RV, right ventricle. We believe, however, that the amount of blood reaching the lungs by any one of the above two routes, though probably was greater in amount than in the first case, yet it was without doubt insufficient to support life for any long period. We base this opinion on the great reduction of size of the pulmonary arteries and veins (less than one-third the normal dimensions) and the diminutive collapsed condition of the left atrium, both TWO CASES OF MONOVENTRICULAR HEART 273 of which spell a proportionately reduced blood stream in the entire circuit, which though sufficient to enable the foetus to live for a few days, is nevertheless undoubtedly incompatible with prolonged life. This case lived about four days. CONCLUSIONS In closing, we would like to draw attention to the following points of interest: 1. The incidence of monoventricular hearts among the Filipino babies is apparently not a very rare condition. In our series we encountered them in the proportion of 1.6 per cent. This fact would seem to call for a more careful clinical study of newly born babies showing obscure cardiac symptoms with fatal results. 2. That the ratio of the weight of the heart to the body weight in our cases was considerably greater than the normal ratio as given by Jackson and Vierordt, denoting undoubtedly a compensatory effort on the part of the heart to carry on circu- lation under abnormal conditions. 3. That not all cases of persistent interventricular foramen can be explained by the failure of expansion of the bulbar portion of the right ventricle or by pulmonary stenosis produced by foetal endocarditis. In many instances it is necessary to invoke also defects of growth, mechanical effect of abnormal blood stream, etc. 4. That the congenital atresia and stenosis of the pulmonary orifice in our cases was probably due to either irregularity of growth of the ventricle and shifting to one side of the union of the right and left bulbar swellings and the septum aorto- pulmonale or to the entire failure of the septum aortopulmonale to unite with the distal lateral bulbar swellings. 5. That monoventricular hearts are perfectly compatible with normal development in intra-uterine life, but when associated’ with pulmonary stenosis, even with patency of the ductus arteriosus, it is probable that life cannot continue for more than a few days, although the collateral pulmonary circulation might be taken up by branches of the bronchial and intercostal arteries. 274 JUAN C. NANAGAS I wish to acknowledge my indebtedness to Dr. H. W. Wade, of the Department of Pathology, for allowing me to report case 2, which came to them at the autopsy table, and to Dr. Arturo Garcia for some helpful suggestions in the preparation of this paper. LITERATURE CITED Buack, Davipson 1913-14 Two cases of cardiac malformation—more especially of the infundibular region. Journal of Anatomy and Physiology, vol. 48, p. 274. Dickson AND Fraser 1913 A congenital abnormality of the heart and blood- vessels. Journal of Anatomy and Physiology, vol. 48, p. 210. Guapstong, R. J. 1915-16 Two examples of cardiac malformation. Journal of Anatomy and Physiology, vol. 50, p. 228. Kerra, Arraur 1909 Malformations of the heart. Lancet, vol. 2, pp. 359, 433, and 519. 1912 Six specimens of abnormal heart. Journal of Anatomy and Physiology, vol. 41, p. 190. Mann, J. Drxon 1907 Cor Triloculare Biatriatum. Brit. Medical Journal, vol. 1, March 16. Parerson 1908-9 Congenital malformed heart. Jour. of Anatomy and Physi- ology, vol. 43, p. lv. Youna, A. H. 1907 Rare anomaly of the human heart—A three-chambered heart in an adult aged thirty-five years. Journal of Anatomy and Physiology, vol. 41, p. 190. PLATES 275 PLATE 1 EXPLANATION OF FIGURES 1 Anterior view of heart of Case 1. A. Anterior coronary artery and great cardiac vein. B. Aorta. C. Pulmonary artery. 2 Anterior half of coronal section of above heart (case 1). A. Aortic orifice. B. Right auricle. C. Crevices representing remains of right ventricle. V. Ven- tricle (single). 3 Posterior half of coronal section of above heart (case 1). B. Right auricle. C. Crevices representing remains of right ventricle. D. Ventricle (single). E. Left auricle. 276 TWO CASES OF MONOVENTRICULAR HEART PLATE 1 JUAN ©, NANAGAS 277 THE ANATOMICAL RECORD, VOL, 20, No. 3 PLATE 2 EXPLANATION OF FIGURES 4 Anterior view of heart of case 2. A. Right auricle. B. Aorta. C. Ven- tricle. 5 Anterior half of coronal section of above heart (case 2). A. Thickened upper part of left wall of single ventricle. B. Right atrium. C. Single ventricle. 6 Posterior half of coronal section of above heart (case 2). B. Thickened upper part of left wall of single ventricle. C. Single ventricle. D. Descending aorta. E. Foramen ovale. 278 TWO CASES OF MONOVENTRICULAR HEART PLATE ? JUAN C. NASAGAS Resumen por el autor, Harvey Ernest Jordan, Universidad Washington, Saint Louis. Nuevas pruebas sobre la funcién de los osteoclastos. El autor presenta pruebas histol6gicas sobre la funcién histo- litica de las células gigantes multinucleadas de la médula 6sea mandibular del gato recién nacido. Estas células gigantes contienen glébulos voluminosos de material 6seo reabsorbido, y son osteoclastos genuinos. La pulpa del 6rgano productor del esmalte contiene también células gigantes semejantes, pro- vistas de glébulos similares. Estos tltimos glébulos son con- siderados por el autor como esmalte superfluo reabsorbido y las células gigantes como ameloblastos. Translation by José F. Nonidez Cornel! Medical College, New York AUTHOR'S ABSTRACT OF THIS PAPER ISSUED BY THE BIBLIOGRAPHIC SERVICE, DECEMBER 27 FURTHER EVIDENCE CONCERNING THE FUNCTION OF OSTEOCLASTS H. E. JORDAN Department of Histology and Embryology, University of Virginia Medical School FIVE FIGURES In a recent paper on the giant cells of the yolk-sac and the bone marrow, the writer (4) included a brief description of ‘oste- olytie giant-cells’ (‘osteoclasts’ of Koelliker) in the mandibular marrow of the new-born cat. In this paper a distinction was made between the ‘hemogenic’ and the ‘osteolytic’ giant-cells of the bone-marrow. The hemogenic giant-cells were shown to develop by excessive growth from hemoblasts. By amitotic division of their transiently polymorphous nucleus these cells become multinucleated, and in this condition occasionally differ- entiate intracellular erythrocytes. The osteolytic giant-cells ‘originate by the aggregation of many nuclei in certain areas which then become separated to form large irregular syncytia, which may fuse with or incorporate osteoblasts and bone cells. These syncytia become placed upon spicules of bone, which they resorb’ (p. 241) (4). The hemogenie giant-cells are accord- ingly comparable to multiple erythroblasts or blood islands; the osteolytie giant-cells are comparable to foreign-body giant-cells. In the osteoclasts were described globules of a substance with the identical structure and staining reaction of the adjacent spicules of bone. These globules were interpreted as resorbed osseous material. This observation constitutes the sole recorded direct evidence that the so-called osteoclasts actually ingest bony substance. The only other approximately direct evidence that these giant-cells possess an osteolytic function is that recorded by Koelliker (5). Following Tomes and de Morgan (7), and Billroth (2) he drove ivory pegs into bone. Subsequent study 281 282 H. E. JORDAN of this experimentally modified material showed an extensive pitting of these pegs, with multinucleated giant-cells occupying an occasional pit. Tomes and de Morgan, and Billroth, how- ever, regarded these pits in the ivory pegs as eroded through the agency of connective tissue. Arey (1) questions the adequacy of the evidence above out- lined as signifying a specific osteolytie function on the part of the so-called osteoclasts. He concludes, moreover, that the hypothesis ‘that they are merely degenerating, fused osteo- blasts, accords better with the known facts’ (p. 335). It seemed desirable, therefore, to devote a renewed and more extensive study to my preparations in which the giant-cells showed these ‘osseous globules.’ The chief purpose of this investigation is to enlarge the body of evidence touching the function of these giant-cells as judged by their cytology and to subject the same to a more rigidly critical analysis. Questions concerning the origin and fate of the osteoclasts will not be here further con- sidered. It is necessary to draw a sharp distinction in this connection between an osteolytic or osteoclastic function and a mere phagocytosis of already fragmented and decalcified bone of resorption foci. The evidence seems unequivocal as con- cerns an osseophagie function of these cells. The central point at issue concerns the active and efficient agent in the dissolution and decalcification of the disappearing spicules of bone in bone development and growth. It should be stated here that Koel- liker (6), in his second extensive paper on bone resorption, no longer regards his experimental evidence with ivory pegs as conclusively indicating a specific osteolytic function of the osteo- clasts. He inclines to ascribe some osteolytie function in grow- ing bones also to the medullary and periosteal connective tissue. The material upon which this investigation is based consists of sections of the lower jaw of a new-born cat. The tissue was fixed with Zenker’s fluid, decalcified in a 5 per cent aqueous nitric-acid solution, imbedded in celloidin, cut at 12u, and stained with hematoxylin and eosin. We are interested here in both the alveolar bone and the included teeth; that is, in the multinucleated giant-cells with osseous globules both of the bone-marrow and of the enamel pulp. OSTEOCLASTS 283 The character of the material is shown in figure 1. The bone is of the cancellous membranous type, with remnants of ‘car- tilage bone’ formed in Meckel’s cartilage of the fetal mandible. The tooth is of course of the deciduous series, and of a stage of development several months prior to eruption. The tooth is Fig. 1 Photomicrograph of transverse section of lower jaw of new-born cat, including tooth. > 12. Over the crown of the tooth the remnant of the enamel pulp has shrunken away from the enamel. Photos by Mr. William 8. Dunn, Cornell University Medical College, New York City. enveloped apically by the primordium of the future cuticular membrane (of Nasmyth) consisting of remnants of the amelo- blasts, the enamel pulp (with its inner stratum intermedium), and the peripheral enamel epithelium. The enamel pulp contains numerous multinucleated giant-cells, some with globules of a material apparently identical with that of the osteoclasts, others in process of degeneration and disintegration. 284 H. E. JORDAN We may to best advantage consider the osteoclasts first. As already stated, these contain larger and smaller globules of a substance with apparently the identical homogeneous structure and acidophilic staining reaction as the spicules of membrane bone (figs. 3 to 5). These ingested globules are commonly located in the portion of the giant-cell next the bone; but ocea- sionally they may apparently lie in the portion farthest removed from the bone (figs. 4 and 5). The latter condition in certain cases is to be interpreted in terms of an adjacent spicule of bone in a higher or lower plane. In figure 4 is shown a giant-cell in process of ingesting a large pestle-shaped mass of free bone. These illustrations would seem to admit of no doubt concerning the osseophagic capacity of these giant-cells. The globular, sharply contoured form of the phagocytosed osseous material indicates that it is ingested only in a fluid or semisolid condition; that is, after a preparatory decalcification of portions of the bony spicule. In figure 5, at the left, is shown a large, relatively clear, circular area, probably representing an osseous globule in a late stage of digestion. The suggestion has been made to me that these globules of bone which I interpret as ingested free portions of bone are actually only extensions of bone within the giant-cells from adja- cent spicules. Such suggestion has no pertinency to my descrip- tions of intracellular globules since it can be proved, by raising and lowering the level of focus, that many globules are actually within the giant-cell protoplasm. An interpretation that pre- sented itself very forcibly to me, not hitherto suggested, and one which I have now thoroughly tested, is that these alleged osse- ous globules are actually only ingested red blood-corpuscles which either remained isolated or became fused into homoge- heous masses. It cannot be denied that these giant-cells do phagocytose erythroplastids as well as osteoblasts and bone cells. Also, some of these smaller globules have approxi- mately the size of a spheroidal erythroplastid. But the red blood-corpuscles of these specimens have a different shape and staining reaction, both in the adjacent blood-vessels and after ingestion by giant-cells. They occur either as cup-shaped, OSTEOCLASTS 285 crenated, or circular biconcave discoid bodies; or they may be variously irregular, or even fragmented. Furthermore, they never exhibit the same deep bluish-red staining reaction; the red blood-corpuscles are either brownish yellow, pinkish brown or light pink in color. In a section of human femoral marrow from a case of fatal typhoid fever, treated with a similar technic, many mononucleated cells can be seen engorged with red blood- corpuscles in all stages of disintegration. In no case, however, is the ingested group of corpuscles fused into a homogeneous mass similar to the globules here described in the osteolytie giant- cells. Moreover, I can find no mention of any condition, either in normal or pathologic histology, where erythroplastids are fused into comparable globules. Nor can these globules be regarded as hyaline degeneration products in view of the generally healthy appearance of these giant-cells. The question arises as to the active agent in the decalcifica- tion and the fragmentation (resorption) of the bone, making possible the ingestion by these giant-cells. There are three obvious possibilities: 1) the medullary connective tissue; 2) the blood-vessels; 3) the giant-cells. If the connective tissue were the specific osteolytic agent in this tissue, we would expect to find numerous globules of bone scattered throughout at least that portion adjacent to the bone spicules. But such globules are lacking in the bone-marrow except occasionally in close proximity to the giant-cells. If the blood-vessels were the effee- tive causative agent in osteolysis in this growing bone, we would expect to find the globules to some extent within the vessels or at least in close proximity to them. Such conditions also do not obtain. Moreover, the vascular supply seems too meager, and is is not generally sufficiently close to the spicule of bone, to furnish plausible support to this assumption. By process of elimination of obviously possible osteolytic agents there remains the osteoclast. This certainly contains globules of ingested osseous material. It is invariably present where bone is being resorbed and reshaped at least during early stages of develop- ment. It is generally in close connection at one or several points with the peripheral layer of the bony spicule (figs. 4 and 5). 286 H. E. JORDAN The evidence from the bone-marrow above described would seem to leave no escape from the conclusion that the giant-cells in this tissue are the active proximate agents in the decalcification and fragmentation, and subsequent ingestion (resorption), of the bone; that is, that they are genuine osteolytie giant-cells or osteoclasts, as originally claimed by Koelliker (5). But this conclusion must be further appraised in the light of data accru- ing from the study, next to be reported, of the multinucleated giant-cells of the enamel pulp. I was at first very much surprised to find what appeared to be identical globules both in the general syncytium and in certain multinucleated giant cells of the enamel pulp of the deciduous pre-erupted teeth in these preparations (fig. 2). Globular shape, variable size, sharp contour of borders, homogeneous structure, and similar staining reaction force the conclusion that these globules of the enamel pulp are practically identical with those above described for the giant-cells of the bone-marrow. In the vase of the enamel organ, with its ‘pulp,’ we are dealing with an ectodermal structure invaginated into the primitive jaw from the overlying epithelium. ‘The cells of the basal layer differentiate into ameloblasts which function in the production of the enamel; the intermediate layers form a loose syncytium, and the periph- eral layer becomes a thin membrane with cells of endothelioid form. The erupting tooth remains covered with. an atrophic membrane, the cuticular membrane of Nasmyth, composed of the nucleated remnants of the ameloblasts, the compressed tooth pulp, and the greatly flattened peripheral enamel epithelium. The erupted crown may remain covered with only ameloblastic remnants. ; The possibility presents itself that the ‘osseous globules’ of the enamel pulp are transported from the marrow, or vice versa. If this were the correct interpretation, such globules should be found in the portion intermediate between the crown of the tooth and the deeper bone-marrow; that is, in the paradental corium of the jaw. The agents in such transference would con- ceivably have to be either blood-vessels or amelopulpar giant- cells; or possibly the globules might find their way from the OSTEOCLASTS 287 enamel pulp to the alveolar areolae through the operation of gravity. The last suggestion may be dismissed as quite improb- able, more especially in view of the fact that no free globules of this sort are found in the intervening connective tissue. If Fig. 2 Photomicrograph of area X of fig. 1. X ca. 600. a, enamel; 6, stra- tum intermedium of enamel pulp; c, fixation (contraction) artifact; d, enamel pulp; e, connective tissue of the dental sac; g.c., two small multinucleated giant- cells, containing enamel globules. The arrows point to some of the globules within the pulp syncytium. These globules do not differentiate themselves sharply in the photograph from the nuclei of the pulpar cells. these globules passed either way via the blood-vessels, we would expect to find them also within these vessels; but such globules are entirely absent from the blood-vessels. Moreover, the enamel organ is non-vascular. The terminal blood channels 288 H, E. JORDAN stop short abruptly upon the outer enamel epithelium of the enamel organ. As regards the giant-cells, none are found just outside the enamel organ in the connective tissue intervening between the lateral border of the tooth and the underlying bone. The possibility of a transportation of these globules from the enamel pulp to the marrow areolae of the alveolar bone or vice versa seems definitely untenable. We are then confronted with the demand for an explanation of the occurrence of these ‘osseous globules’ within the enamel pulp and the included giant-cells. These giant-cells are formed in a manner quite similar to that by which the giant-cells of the alveolar bone arise, that is by closer fusion of ‘cells’ of the pulp syncytium. They form, therefore, in the manner of foreign- body giant-cells. These giant-cells of the enamel pulp certainly ingest the osseous globules; many of which lie free within the pulp, or in vacuoles in the pulp cells, and especially as large free, spheroidal and greatly elongated, globules next the enamel. The giant-cells are phagocytic for these globules, and they subsequently disintegrate by a process initiated by a general karyorrhexis of the multiple nuclei, a stage of which gives a simulacrum of multipolar mitoses. During this process of degeneration the cytoplasm of these cells becomes intensely oxyphilie. That the globules are not single, or fused masses of, red blood- corpuscles is here even more definitely indicated than in the case of the osteoclasts. Blood-vessels filled with erythroplastids abut upon the enamel organ, so that it is readily possible to bring such a vessel and a portion of the pulp with globules into the same field, when careful comparisons can be made between the two. No blood-vessels can be seen in my preparations enter- ing the enamel organ.! The erythroplastids differ in shape, size, 1T am unable to confirm the conclusion of Hopewell-Smith that the enamel pulp (stratum intermedium) of the kitten’s tooth is supplied with a capillary plexus (‘‘Normal and pathological histology of the mouth,”’ vol. 1, pp. 263-264). His figures 227 and 229, supplied to illustrate his description of a vascularized pulp, do not obviously bear such interpretation. As near as one can determine from these photomicrocraphs, the capillaries end abruptly on the outer surface of the enamel organ, as in my preparations. Hopewell-Smith introduces this OSTEOCLASTS 229 and staining reaction from the ‘osseous globules’ in the same manner as above described for the alveolar marrow. It must be added, however, that many of the pulp globules have a sort of brownish-gray, or less deeply bluish-red, color than those of the osteoclasts. This difference may signify a later stage in resorp- tion in the case of the pulp globules. That the globules also in the enamel pulp do not signify hyaline degeneration seems defi- nitely indicated by the generally healthy character of the nuclei of the pulp syneytium. The crucial point concerns the origin and significance of these pulpar osseous globules. Two possibilities are presented: 1) that they represent decalcified resorbed enamel; 2) that they represent a superfluous enamel secretion on the part of the cells of the enamel pulp, which is then resorbed through the agency of newly formed polynucleated giant-cells. The latter possi- bility has a color of reasonableness, since the cells of the enamel pulp are originally very similar to those of the adjacent amelo- blasts and would accordingly be expected to have similar funec- tional capacities. It is difficult definitely to dispose of this suggestion. ‘There is, however, one datum of at least apparent countervailing significance: large elongated globules occur between the inner border (stratum intermedium) of the enamel organ and the definitive enamel. Moreover, the border of the enamel in such regions appears uneven, and occasionally even jagged, as if enamel were being dissolved peripherally. It would seem probable, in view of this observation, that the newly subject of the blood-supply of the enamel organ with the statement that‘tThe vascularity or otherwise of the enamel organ is not yet determined, many compe- tent authorities holding opposite opinions on this subject. Thus Lionel Beale, Leon Williams, Howes, and Paulton assert that a vascular network is to be found in the stratum intermedium, while Tomes, Paul, Andrews, Wedl, Sudduth, and Magitot affirm its non-vascularity. “The author, in a joint paper with H. W. Marett Tims, has recently described the presence of blood-vessels, containing erythrocytes in the enamel organ of the Australian wallaby. (‘Tooth germs in the wallaby, Macropus billiardieri’ ; Proc. Zoolog. Soc., London, 1911)’ (pp. 261-262). He then proceeds to deseribe “The blood supply of the developing dental tissue’’ in Mammalia and illus- trates his description as regards the vascularization of the enamel pulp with a ‘coronal section through the mandible of a kitten’’ (pp. 259 and 264), which he interprets as showing pulp capillaries. THE ANATOMICAL RECORD, VOL, 20, No. 3 290 H. B. JORDAN formed enamel becomes to some extent resorbed and reshaped peripherally before the deciduous tooth is finally erupted. But in the event that the latter should prove the correct interpreta- tion of the presence of these globules within the enamel pulp, I am quite unable to decide, on the basis of available data, as to whether the active agent of resorption is here the enamel pulp as a whole or specifically the giant-cell (adamantoclast, amelo- elast). That the blood-vessels have nothing directly to do with the process of decalcification and resorption of the enamel seems clear from the fact that they are excluded from the enamel organ. But it is to be recognized that blood-vessel intervention in the process of resorption might be viewed as simply the obverse of the logically assumed nutritive réle of the blood- vessels with respect to enamel elaboration. All things con- sidered, I incline to the view that these globules of the enamel pulp are superfluous secretion products of slightly active poten- tial ameloblasts of the stratum intermedium of the pulp, and that the formation and presence of multinucleated giant-cells signifies the fulfillment of a demand for the removal of the globules by phagocytosis. But the alternative view that the globules are derivatives of the definitive enamel, resorbed either through the agency of the pulp as a whole or specifically through the agency of the newly formed giant-cells is not disproved. Under either view, however, the pulpar giant-cells are ameloclasts in the sense that they ingest and destroy enamel. The resemblance, or apparent chemical identity, between the globules ingested by the osteoclasts and those of the ameloclasts results from the essential chemical identity between bone and enamel. While the evidence is fairly conclusive that the osteo- clasts are the active specific agents in the resorption of bone in these specimens, it warrants for the present only the assertion that the giant-cells of the enamel pulp ingest and destroy enamel globules derived from an unknown source by action of an unknown agency. This source may obviously be either the newly formed enamel or the cells of the pulp syncytium. The obvious active agent in resorption may be either the enamel pulp or the newly formed giant-cells. Less obvious sources and factors cannot, however, at present be definitely excluded. OSTEOCLASTS 291 As regards the osteoclasts, two facts stand in sharp contradic- tion to Arey’s (1) conclusion that they should be interpreted as degenerating fused osteoblasts: 1) Osteoclasts arise in large part directly from the connective tissue stroma of the marrow, independently of osteoblasts; 2) the younger osteoclasts exhibit no signs of degenerative changes, either cytoplasmic or nuclear. SUMMARY In the mandible of the newborn cat occur many multinu- cleated giant-cells which contain a variable number of spheroidal globules of a material apparently identical with bone. These giant-cells occur both in the marrow of the developing jaw bone and in the enamel pulp of the developing tooth. Both groups of cells arise in a similar manner; in one case by fusions among the cells of the marrow reticulum, in the other case by fusion of cells of the dental pulp. In respect of the mode of origin, and of their function, these cells accordingly resemble foreign-body giant-cells. The former are osteoclasts, the latter ameloclasts; one group ingests and destroys globules of bone, the other globules of enamel. The fundamental factors operating in the decalcifi- eation and dissolution of the bone and of the enamel remain unknown. In the case of the osteoclasts, however, the evidence suggests that the giant-cells are the active specific agents in the dissolution of the bone, as well as in the elimination through phagocytosis of the products of .dissolution. The fact that in many other locations where resorption of growing bone occurs, similar giant-cells are very numerous, though without osseous inclusions, is in accord with this view. The presence or absence of the products of resorption in the shape of globules, in the cytoplasm of specific osteolytie giant-cells, may be correlated with the relative rapidity, or perhaps the peculiar mode, of resorption of the bone. The products of osseous resorption of specific osteolytic giant-cells, generally of ultramicroscopic size, may under certain conditions be of microscopic size, like the globules here described for these osteoclasts and ameloclasts. 292 H. E. JORDAN ba | LITERATURE CITED Arey, L. B. 1920 The origin, growth, and fate of osteoclasts and their relation to bone resorption. Am. Jour. Anat., vol. 26, pp. 315-347. Brttrota 1869 Allg. chirurg. Pathol. und Therapie. 4. Aufl., S. 195 (cited from Koelliker (6)). Hoprwett-Smiru, A. 1918 Normal and pathological histology of the mouth. Vols. 1 and 2. P. Blakiston’s Son & Co., Philadelphia. Jorpan, H. E. 1918 A contribution to the problems concerning the origin, structure, genetic relationship, and function of the giant-cells of hemopoietic and osteolytic foci. Am. Jour. Anat., vol. 24, pp. 225-269. Kog.uiker, A. 1872 Weitere Beobachtungen iiber das Vorkommen und die Verbreitung typischen Resorptionsflichen an den Knochen. Verh. d. phys.-med. Gesellsch. in Wiirzburg. N. F. Bd. 3, S. 215-228; and Arch- ives de Zoologie expérimentale. T. 2, pp. 1-28 (1873) (cited from Koelliker (6)). 1873 Die normale Resorption des Knochengewebes und ihre Bedeu- tung fiir die Entstehung der typischen Knochenformen. Vogel, Leip- zig; S. 86. Tomes AND DE More@an 1852 Observations on the structure and develop- ment of bone. Phil. Trans. (cited from Koelliker (6)). PLATES. PLATE 1 EXPLANATION OF FIGURES 3 Large bilobed osteoclast, containing two large globules of osseous material. The osteoclast rests upon a spicule of bone. X 825. Drawings by Miss Emma M. Whitfield, Richmond, Virginia. (The three water-color illustrations, and the corresponding microscopic preparations, were shown as demonstrations at the meetings of The American Association of Anatomists, in Washington, April 1 to 3, 1920.) 4 Osteoclast, at the left of the spicule of bone, containing four smaller osse- ous globules. Along the lower border of the giant-cell lies a large pestle-shaped mass of osseous material in process of ingestion. X 825. 5 Osteoclast, continuous below with several osteoblasts, covering the spicule of bone. It contains five small deeply staining globules, and one larger lighter- staining globule. The latter probably represents a large osseous globule at a later stage of resorption. X 825. (The osteoclasts of figs. 3,4, and 5 are from the marrow areolae of the subdental bone, corresponding to that along the lower margin of fig. 1.) 294 Resumen por los autores, Paul K. Webb y J. Barrett Brown, Universidad Washington, Saint Louis. Un caso de barras costales independientes en e lepistrofeo del hombre. En el presente trabajo se di a conocer la existencia de un par de procesos costales independientes en el epistrofeo de un var6n negro. Las barras costales consisten en dos osfculos independientes de un centimetro y medio de longitud, y del mismo tamafo, que se articulan por medio de una anfiartrosis con protuberancias cortas que se extienden desde el cuerpo del axis. Estas protuberancias ocupan la posicién del extremo proximal de la barra costal normal. Las barras costales inde- pendientes se extienden inferiormente y lateralmente, sin fundirse con los pediculos posteriores 0 con los verdaderos procesos trans- versos. Los orificios costo-transversos son por consiguiente incompletos, abriéndose hacia los lados. En el atlas no existen barras costales; los cuerpos y arcos de la segunda y tercera vértebra son continuos en cierto grado, y esto es probablemente una condicién secundaria. Translation by José F. Nonidez Cornell Medical College, New York AUTHOR'S ABSTRACT OF THIS PAPER ISSUED BY THE BIBLIOGRAPHIC SERVICE, JANUARY 17 A CASE OF INDEPENDENT COSTAL BARS OF THE EPISTROPHEUS IN MAN PAUL K. WEBB anp JAMES BARRETT BROWN Department of Anatomy, Washington University TWO FIGURES This rare variation was discovered in the class laboratory during the preparation of the vertebral arteries. The subject was a male negro of advanced age, as indicated by extreme emaciation and wrinkled skin, sparseness of hair, toothless jaws, and fragile bones. The record taken from the mortuary report gave his age at ninety-five years. On tracing the vertebral arteries through the transverse for- amina toward the cranium, our attention was arrested on reach- ing the epistropheus by the mobility of the two costal bars of that vertebra. Examination disclosed two ossicles, similar in form and of nearly equal size, articulating, one on either side, with the body of the epistropheus (figs. 1 and 2). Each bone presented the shape of a little horn, directed downward, back- ward, and a little lateraliy, tapering below to a free blunt extrem- ity. The ossicle is bent into a well-marked curve, convexity forward. That of the right side measured 9 mm, in length and 4 mm. in the greatest diameter; the left bone, 10 mm. and 4 mm. They occupied the usual position of the costal component of the cervical transverse process and were therefore in series with the costal bars of the succeeding vertebrae. The ossicles do not have a true capitular termination against the body of the epis- tropheus, but articulate with a truncated process springing from the base of the root of the arch just beneath the superior artic- ular surface. A careful preparation of the joint revealed an amphiarthrosis, the articulating surfaces being covered with cartilage, without, however, a joint cavity or synovial layer. -The union was maintained by fibrous tissue apparently in con- 297 THE ANATOMICAL RECORD, VOL, 20, NO. 3 298 PAUL K. WEBB AND JAMES BARRETT BROWN nection with the periosteum and tendons of muscles. As already intimated, the joint permitted a small degree of motion of the ossicle. The opposite extremity of the latter ended free, did not articulate, or even come into contact with the truncated process representing the posterior bar of the transverse process. The transverse foramen was therefore open laterally. Other abnormalities were subsequently discovered more or less closely related to that just described. The lamina and inferior articular process of the left side of the epistropheus are continuous with the lamina and the superior articular process of the third vertebra; bony union also obtains between the third and fourth vertebrae in two regions, viz., between the articular processes of the right side and between the bodies on the left. Some degree of thickening of the articular processes and laminae is noticeable where the union exists. The union between the bodies of the third and fourth is marked by a bony eallosity. A certain amount of deformation of the bodies of the fourth and fifth vertebrae, affecting the anterior opposed margins, is evident. The atlas also presents a variation. This rudimentary bone is still further reduced by the absence of its anterior costal bars. In place of them, there was found on each side a slender ligament completing the transverse foramen anteriorly. This band was stretched between the lateral free extremity (tubercle) of the transverse process of the atlas and a prominent, short, thick process of the lateral mass opposite the front of the superior articular surface. This may be a vestige of the costal bar or a capitular process. As to the occurrence of like variations, it is of course well known that absence of the costal bar of the atlas has been fre- quently observed; Macalister (’93), Bolk (’99), and Le Double (12) in particular have described and discussed the significance of this variation. All degrees of defect of this bar, ranging from nearly its normal size to complete absence, have been noted. Elliot Smith (07) has described a case of fusion of the atlas and axis in which there was no evidence of disease. In the present case the cause of fusion between the laminae and artic- ular processes of the epistropheus and third vertebra cannot ° COSTAL BARS OF EPISTROPHEUS IN MAN 299 with certainty be referred to an inflammatory process; this is probably the cause. The deformation and ankylosis of the bodies are evidently the result of disease; the irregular contour is in contrast with the smoother surface where the axis and third vertebra are continuous by their articular processes. If the latter union were primary, it is not improbable that the fixation of the joints between these bones might have been a predispos- ing factor in the location of the disease process in the joints of the succeeding vertebrae. The phenomenon of coalescence of vertebrae both as a normal ontogenetic process and as a not uncommon variation is well established by observation: fusion of the cervical vertebrae to constitute a single piece, comparable to the status of the sacrum in man, is normal among cetaceans; there is marked tendency toward fusion of the atlas with the occipital bone in man, as shown by the descriptions of many cases (Dwight, ’09; Kollmann, ’04; Swjetschnikow, ’06, and others). In a large percentage of such cases there is no evidence of disease as an influence in bringing about the fusion. Regarding the occurrence of independent costal bars in the cervical region, a very large literature has grown up chiefly from interest in cervical ribs. The known eases of cervical ribs have been collected and reviewed by Le Double and additional facts have been brought to light by the more recent work of Todd (12). The usual type of cervical rib is connected with the seventh vertebra; a rare association is that with the sixth. Szawlowski (’01) has reported a case of costal rudiments in connection with the fourth bone. Macalister (94) has found an independent bony granule in the pre-arterial crus of the trans- verse process of the axis. There is evidence, according to Fawcett (’10), of independent chondrification of the costal bars. So far as we know, no cases of vestigial ribs have been found in connection with the atlas, epistropheus, and fifth vertebra. Consideration of all the conditions in the present case lead us to the conclusion that the independent ossicles have developed from centers separate from the ossific processes of the epistro- pheus and by their relations must be regarded as vestigial ribs. The ossicle represents probably only the neck of a rib, since it 300 PAUL K. WEBB AND JAMES BARRETT BROWN does not reach the true transverse process and at its vertebral end articulates with a prominent process (capitular?) without, however, expanding to form a head. It is comparable to the rib rudiments in the cephalic part of the cervical region of reptiles. The chief interest of this case, it seems to us, lies in its possible connection with the tendency to regression manifested in so many directions by the components of the head-neck region. Bolk (loc. cit.), who has studied this phenomenon, points out the evidences of this reaction in the reduced state of the atlas and its proneness to further degeneration and assimilation with the occipital; the imperfection of the first spinal nerve correlated with the absence of muscles in the intertransverse and inter- spinous series, ete. Further consideration of this question has been given by Terry (717) in connection with the development of the occipital region of the chondrocranium. ‘The present case exhibits a group of changes, differing in kind (defect of atlas, coalescence of vertebrae, abortive development of epistropheus), which may, nevertheless, be the result of a single factor operat- ing upon the formation of this transitional zone between the head and neck. The authors wish to express their appreciation of the assist- ance given them by Dr. R. J. Terry in the preparation of this report. COSTAL BARS OF EPISTROPHEUS IN MAN LITERATURE CITED Box, L. 1899 Neder. Tijdschr. voor Geneeskunds, vol. 1. Dwiaut, T. 1909 Anat. Rec., vol. 3. Fawcett, J. M. 1910 Journ. Anat. and Physiol., vol. 44. KouuMANN, J. 1904 Anat. Anz., Bd. 25. Le Dovuste, A. 1912 Traité des variations de la colonne vertébral. Vigot. Macauister, A. 1893 Jour. Anat. and Physiol., vol. 32. 1894 Jour. Anat. and Physiol., vol. 28. Smith, G. Evuior. 1907 Anat. Anz., Bd. 31. Swuetscunikow, W. A. 1906 Arch. f. Anat. u. Physiol. SzawtowskI, J. 1901 Anat. Anz., Bd. 20. Terry, R. J. 1917 Jour. Morph., vol. 22. Topp, T. W. 1912 Jour. Anat. and Physiol., vol. 46. 301 Paris. PLATE 1 EXPLANATION OF FIGURES 1 Independent costal bars of the epistropheus in man. Cervical and upper thoracic spine from in front. X 2. 2 Independent costal bars of the epistropheus in man. Cervical and upper thoracie spine from the left side. 2. 302 Resumen por F. 8. Hammett, por el autor Vincent Vermooten, Universidad del Cabo, Africa del Sur. Estudio de la fractura del epistrofeo en el ahorcado, con una nota sobre las causas posibles de muerte. En el presente trabajo el autor presenta una breve descripcién anatémica de la naturaleza de las fracturas cervicales observadas en cuatro casos de ejecucién judicial en la horea. En todos los casos ha encontrado una dislocacién de la segunda y tercera vértebra, en direeci6én inferior. La primera y segunda vértebra estaban todavia articuladas correctamente, asi como el atlas con el occipucio. Puesto que el ligamento transverso conservaba todavia su posicién normal, mientras que el arco neural estaba desprendido de la vértebra, el autor cree que este es el resultado ordinario después de morir ahorcado y, por consiguiente, no esta conforme con la opinién de Gray, que admite la ruptura del ligamento transverso en tales casos. Vermooten cree que la muerte se debe probablemente a la rotura de la médula. Translation by José F. Nonidez Cornell Medical College, New York AUTHOR'S ABSTRACT OF THIS PAPER ISSUED BY THE BIBLIOGRAPHIC SERVICE, DECEMBER 7 A STUDY OF THE FRACTURE OF THE EPISTROPHEUS DUE TO HANGING WITH A NOTE ON THE POSSIBLE CAUSES OF DEATH VINCENT VERMOOTEN Anatomical Laboratory of the University of Cape Town, South Africa TWELVE FIGURES The cause of death due to hanging (judicial hanging), although a very interesting phenomenon, has apparently not been the result of much investigation. It has usually been taken for granted that death is due to rupture of the transverse ligament of the atlas with the resulting crushing of the cord and medulla by the odontoid process of the epistropheus. That this is not always the case is shown by the examination of four cases of hanging which the author investigated in this laboratory during the latter part of the year 1919. On examination it was found that in all the four cases there was a downward dislocation of the second and third cervical vertebrae. The first and second vertebrae were still properly articulated as well as the atlas with the occiput, the ligamentum apicis dentis being still firmly attached to the occiput and to the tip of the odontoid process of the epistropheus. Another remarkable fact was revealed: the transverse liga- ment of the atlas was still in its normal position, holding the odontoid process as in life. There was not even the faintest trace of a rupture of the ligament in any of the four cases. In the first cases (figs. 1, 2, 3,) the atlas and the epistropheus were well articulated, as were the atlas and occiput. The epistropheus and third cervical vertebra were dislocated down- ward, while the transverse ligament of the atlas was intact. The epistropheus, strangely enough, was fractured, the neural arch being altogether broken off from the body. The fracture 305 306 VINCENT VERMOOTEN on the right side was posterior to the foramen transversarium, but anterior to the inferior articular facet. On the left-hand side the fracture was through the pedicle and through the trans- Tig. 1 Body and neural arch of vertebra, Fig. 2 Portions of vertebra viewed from the right side. Fig. 3 Portions of vertebra viewed from the left side. verse element of the transverse process, leaving the greater part of the foramen transversarium anterior to the break. In the second case (figs. 4, 5, 6) the vertebrae were again articulated as in the first case, with the transverse ligament of THE FRACTURE OF THE EPISTROPHEUS 307 the atlas altogether intact. The neural arch was also fractured on both sides. On the right-hand side the break was anterior to the inferior articular facet and posterior to the foramen trans- versarium, leaving the foramen quite whole. On the left-hand side there was a break in the same position as on the right, but the sides of the foramen transversarium were also broken so that the transverse process was altogether broken off from the vertebra. Fig. 4 Body and neural arch of the vertebra. Fig. 5 Portions of vertebra viewed from the right side. Fig. 6 Portions of vertebra viewed from the left side. In the third case (figs. 7, 8, 9) once more the conditions of articulation were as in the previous cases, with absolutely no sign of rupture of the transverse ligament of the atlas and the neural arch was once more totally broken off from the body of the vertebra. The fracture on the right-hand side was in exactly the same position as the fracture on the right-hand side of the second case. On the left-hand side the fracture was much more serious, for, 308 VINCENT VERMOOTEN in addition to a fracture similar to the one on the right-hand side, there was also a fracture through the pedicle and through the junction of the posterior third and anterior two-thirds of the superior articular facet, anterior to the foramen transversarium. A large part of the arch containing the foramen transversarium was thus broken from the lamina on the one hand and from the body of the vertebra on the other. ’ Fig. 7 Body and neural arch of the vertebra. Fig. 8 Portions of vertebra viewed from the right side. Fig. 9 Portions of vertebra viewed from the left side. In the fourth case (figs. 10, 11, 12) the articulations and the condition of the transverse ligament of the atlas were again exactly similar to the previous three cases, the break on the right-hand side was also similar. On the left-hand side the break varied again; this time the break was through the costal element of the transverse process, through the foramen trans- versum and through the posterior part of the superior articular THE FRACTURE OF THE EPISTROPHEUS 309 surface. In addition to this, it was found that the atlas was also mutilated, the transverse process being broken off from the lateral mass, the fracture being through the roots of the trans- verse and costal elements. The transverse process itself was also broken into three pieces. In Gray’s Anatomy, page 358, we find the following statement: Fig. 10 Body and neural arch of vertebra. Fig. 11 Portions of vertebra viewed from the right side. Fig. 12 Portions of vertebra viewed from the left side. Dislocation of the occipital bone from the atlas has been recorded only in one or two cases; but dislocation of the atlas from the epi- stropheus, with rupture of the transverse ligament of the atlas, is much more common: it is the mode in which death is produced in many cases of execution by hanging. From this it appears that rupture of the transverse ligament is a fairly ordinary procedure, especially in cases of death due to judicial hanging. On examination, however, of four cases of THE ANATOMICAL RECORD, VOL, 20, No. 3 310 VINCENT VERMOOTEN death by hanging it was found that not only was the transverse ligaments of the atlas not ruptured, but there was not the faint- est sign of a rupture, the whole ligament was intact, including even its attachment to the atlas; the dens of the epistropheus being held as though it were the true body of the atlas. Treves and Keith, in their “‘Surgical Applied Anatomy,” page 645, say: In the atlanto-axial region the amount of displacement that follows upon luxation of the two bones from one another is such that the cord is, as a rule, severely crushed, and death ensues instantaneously, as is seen in cases of death by hanging. The crushing of the spinal medulla is here also evidently attributed to the odontoid process. It may be that occasionally the transverse ligament ruptures on hanging and that under these circumstances the cord is crushed and causes instantaneous death, but in these cases the ruture is most likely due to congenital weakness of the trans- verse ligament or perhaps to a pathological condition of the transverse ligament or atlas. In the cases of the four well-built young colored men, it is not possible to ascribe death to rupture of the transverse ligament. Death would be largely due to rupture of the cord, which is allowed for by the downward dislocation of the third cervical vertebra from the second. It is difficult to say where the rup- ture actually takes place, for the specimens were examined long after the postmortems had been held. To what other cause instantaneous death can be due is difficult to say, as crushing of the cord, as mentioned by Treves and Keith, does not seem very probable, for nothing projects into the canal. The elasticity of the transverse ligament may allow for an instantaneous, slight protrusion of the odontoid process into the neural canal, but this small amount can be compensated for by the fact that the cord is suspended in the neural canal. It is difficult to say what part the fracture of the epistropheus plays. Perhaps this also aids in the crushing of the cord. ; THE FRACTURE OF THE EPISTROPHEUS 311 In addition to the probable rupture of the cord, one must also take into account the rupture of the big blood-vessels of the brain and vertebral arteries in addition to shock and the rup- ture of several of the muscles of the neck, such as the M. ster- nohoideus, M. omohoideus, and others, as well as the possible rupture of the carotid arteries. LITERATURE CITED Gray Anatomy, Descriptive and Applied. Treves AND Kerra Surgical Applied Anatomy. Resumen por el autor, Paul E. Lineback, Universidad Emory, Atalanta, Georgia. Un easo de polidactilia en un embrién de 22 mm. El caso presentado en este trabajo, si el autor esta bien infor- mado, es el mds*j6ven mencionado hasta el presente, debiendo su significacién principalmente a este hecho. Ademés_ sus- ministra datos adicionales intesantes sobre el problema del primer hueso metacarpiano y sobre el problema mas general del polidactilismo. En este caso el autor encuentra, sin embargo, pocas pruebas concluyentes en favor de las teorfas relacionadas con ambos problemas. El tinico punto valioso que el autor puede ofrecer es que el presente caso lleva el problema del polidac- tilismo desde el catdlogo de los factores causativos extrinsecos al dominio de los factores formativos tempranos. Translation by José F. Nonidez Cornell Medical College, New York AUTHOR'S ABSTRACT OF THIS PAPER ISSUED BY THE BINLIOGRAPHIC SERVICE, FEBRUARY 7 A CASE OF UNILATERAL POLYDACTYLY IN A 22-MM., EMBRYO P. E. LINEBACK Emory University School of Medicine ONE FIGURE In the laboratory of the author there is an embryo 22 mm. in length, with an extra digit on the right hand at the base of the metacarpus of the thumb. It was noted by Doctor Streeter while making measurements of the embryo, and he marked it as being, from all available records, the youngest case thus far discovered. This fact seems to warrant the author in making a study and report of it, with a brief survey of the literature on the subject. : The embryo came into the laboratory without data as to its parents or details of its appearance. It has a crown-rump length of 22 mm. and is well formed in every detail, with mem- branes in normal state. The two hands are similar in every respect, except that the thumb on the right hand is a trifle smaller than the left thumb. The breadth of each hand, midway across the palm, is 2 mm., and the length, from a line across the wrist just back of the thenar eminence to the tip of the middle finger, is 2.5mm. The right thumb is 1.1 mm. long and 1 mm. thick. Attached to the base of its metacarpus is the extra digit. It stands out from the surface at right angles and is uniform in size and shape. Near the tip it bends slightly forward and terminates in a blunt rounded point. It is 1 mm. long and 0.6 mm. thick. Serial cross-sections were made of the whole fore- arm and hand beginning at the tip of the fingers and going to the elbow. The sections were cut 10, thick after staining the specimen in toto in cochineal. 313 314 P. E. LINEBACK Fig. 1 Outline drawing from reconstructed model. X 22. A. Surface view showing position of extra digit. B. Cartilaginous skeleton showing relationship of extra digit to other skeletal units UNILATERAL POLYDACTYLY IN A 22-MM. EMBRYO 315 Microscopic study shows the cartilages of the wrist, hand, and fingers present. All the separate units of the parts are in place and are still in process of cartilage formation. Each piece shows a peripheral zone of condensed cells beginning to show the features of a perichondrium, and a central core characterized by a network of hyaline strands, in the meshes of which may be seen large cartilage cells. The skeleton of the extra digit is a single piece of cartilage having the above characteristics. It is a sepa- rate unit with close relationship to the base of the metacarpus, and not an offshoot or spur from it. Two muscles are contained in the digit, a volar and a dorsal muscle. The one on the dorsal side extends through the mesen- chyma out toward the tip, but ending short of it. Its origin and identity are uncertain; probably it comes from the outer head of the first dorsal interosseous muscle. The volar muscle can be more certainly identified. It arises from the abductor policis brevis and extends to near the tip of the digit on the palmar side. Nerves cannot be identified and vessels are seen only as undifferentiated capillaries. In going through the literature, no cases are cited of poly- dactyly in the young embryo; all are late foetuses or postnatal cases and the majority are in adult life. Salzer (’98), reporting two cases of triple phalangeal thumbs, opened the question as to which phalanx is missing in the ordinary thumb, the end phalanx or the middle phalanx. He quoted Windle, who made a general summary of such cases by expressing the opinion, with some reservations, that the extra phalanx must have occurred from the fact that the distal bone center of the first metacarpus developed independently. He referred to Uffelman’s work, in which it is shown that at the capitellum of the first metacarpus a special bone center is present without ever existing independ- ently. He thinks that this extra center may give rise to a super- numerary phalanx, which would be the main phalanx. Salzer quoted Pfitzner also, who seemed to hold that a triple phalangeal formation is, for a brief period, a normal state and that the double phalangeal thumbs and toes have come about in this manner, from the merging of the middle and end phalanges 316 P. E. LINEBACK gradually a typical and enlarged phalanx has resulted. In sup- port of this he cites a case of a girl with a strikingly large end phalanx consisting of two pieces which have not been completely fused. Jurcie (’06) reported a case of hyperphalangea in both thumbs. In this report he took up the problem of whether the thumb should be considered as possessing normally three pha- langes and no metacarpus, or a true metacarpus and only two phalanges. He cites the fact that the first bone of the thumb develops in the same manner as the phalanges, the head and shaft from a common primary center, and the base from an epiphysis. The development of the metacarpals is just the reverse, the base and shaft arise from a common primary center and the head from an epiphysis. He concludes, however, that from the manner of muscle attachment to the first metacarpus and noting the presence of the extra ossification center in some mammals, and occasionally in man, this is a true metacarpus and not a basal phalanx. Stieve described a case of bilateral hyperphalangea (’15-16) and quoted Krause (’09), who objected to Pfitzner’s work on the ground that it dealt with malformations, which was poor material for drawing such conclusions. In Stieve’s case the end phalanx, which should be shorter than in normal diphalangeal thumbs, is especially long, and in Salzer’s cases the two end phalanges show no proportionate shortening. He finds also that whereas there was restricted movement between the end and middle phalanges of Hilgenreiner’s case, the movement in his case was especially free. Backed by these points, he comes to the conclusion, differing with his predecessors, that the end phalanx in the diphalangeal thumb is not a fusion of the middle and end phalanges. He seems to hold to this opinion more firmly when he notes that we are not dealing with perfect tri- phalangeal thumbs in reported cases, but the extra piece is only the radial side of the middle phalanx. Hilgenreiner apparently has the most complete list of cases of hyperphalangeal thumbs and the most valuable data concern- ing the subject. According to him, 107 three-jointed thumbs, fifty-eight cases, had been noted to date (’10). He goes to UNILATERAL POLYDACTYLY IN A 22-MM. EMBRYO 317 some length in discussing the condition and makes a definite classification of the cases. In the first class he would include cases where there is only partial separation of the end and middle phalanges—incomplete hyperphalangea. In class 2 he would include only such cases as show complete formation of the middle phalanx having a diaphysis and an epiphysis—true hyperphalangea. In these cases the thumb characteristics have been lost and the structure is more like an extra index-finger. This change of characteristics is proportionate to the degree of separation of the phalanges. He is quite firm in his opinion that the condition of diphalangeal thumb has arisen from a fusion of the end and middle phalanges in early stages of for- mation. He sees two possible explanations in these cases of anomalous thumbs, but does not pursue either at length. He speaks of a palingenesis of the middle phalanx traceable to some endogenous cause. This factor is mentioned by others also, Minoura and Prentiss. He also states that the supernumerary phalanx is not always to be explained as a palingenesis of the middle phalanx, since it may arise from the epiphysis of the sec- ond phalanx. In such cases triphalangeal thumbs appear only postpartem in the first, second, or third year of child life. Prentiss (’03) has contributed to the subject a valuable piece of work, dealing with it in a somewhat broader fashion than Hilgenreiner, although his study of cases in man, especially of thumb variations, is rather too limited for valuable application here. He states that ‘variations are found chiefly in digits which are modified, rudimentary or vestigial.’’ As to the causes of polydactyly he has this to offer: “in man it is not a definite number of extra digits but a tendency to duplication which is inherited” and ‘duplication of functional digits is probably caused by germinal variations alone.”’ After reviewing the above literature, which is, although brief, a general and inclusive statement of opinions on the subject, several problems present themselves or at least several aspects of the same problem. ‘There appears to be a difference between hyperphalangea and polydactyly. The former is characterized by the presence of an extra phalanx, with the main disfiguration 318 P, BE. LINEBACK of the thumb an increase in its length or a deflection to the ulnar side. The latter is marked by the presence of an extra digit, either large or small, fully formed or rudimentary, which stands apart from the other digits. The problem of di- and tripha- langeal thumbs, as to how the normal thumb should be regarded and the origin of the extra phalanx in triphalangea, comes under the head of hyperphalangea. Here would be placed the cases of Jureié, Salzer, Stieve, and some of Hilgenreiners. Under polydactyly would be included such cases as Prentiss’, others of Hilgenreiner’s, and the author’s. Another point is that variations in the thumb should be con- sidered in a special class apart from variations in the other fingers, since here is found, in the normal state, a condition unlike that in the others. Prentis’s statement that, ‘variations occur chiefly in digits — that are modified,’ would lend emphasis to this, and Hilgenreiner seems to have considered it worth while to tabulate over one hundred cases of thumb variations. Standing out prominently among these points is the problem of the causative factor in polydactyly and hyperphalangea, and how this factor operates. Upon this point the author’s case presents some features, not noted in others, which might be considered a little more at length. Here is a clear case of poly- dactyly having an extra digit with a separate piece of cartilage. All the other units of the wrist and hand are present but still in the cartilaginous state. It is conclusive that the causative fac- tor of splitting of a digit by an amnionic band is not operative here. Nor is the factor of an extra phalanx arising from a diverted center of ossification to be applied, since the digit is present before ossification appears anywhere in the hand. The specimen permits of an investigation further back than the beginning of ossification. Here might be applied the theory of palingenesis as suggested by Minoura, Hilgenreiner, and Pren- tiss, although the last author might not include it here. Or again, Prentiss’ reversion to a not remote ancestral form, an inheritance, working through Mendel’s law, might be applied. He states that ‘‘all cases of polydactyly, not due to external UNILATERAL POLYDACTYLY IN A 22-MM. EMBRYO 319 causes, may be the result of inheritance.’’ These two theories presuppose a parental state from which they may work, and the natural question arises as to what caused the first deviation in the original parent. ‘Germinal variation’ is an expression com- monly used by investigators and especially by Prentiss when he says, ‘but the duplication of functional digits are probably caused by germinal variation alone.’’ He further states that, ‘as to the cause of these germinal variations . . . . we know little or nothing.’’ In his comprehensive work, “Science and philosophy of the organism,” Driesch put the essence of the matter in a more concrete form when he gave expression to ‘feeling for form.’ Just how far these expressions are usable is a question; they at least emphasize the fact that search must be made in the field of cytology and cytochemistry in dealing with the state of abnormal thumbs. CONCLUSIONS The author feels justified in drawing the following conclusions: 1. Hyperphalangea and polydactyly are sufficiently different to be put into separate classes. 2. The thumb offers sufficient significance to warrant separate study in its variations. 3. The author’s case offers proof that some cases of poly- dactyly owe their origin to earlier causes than external factors or deviation of ossification centers. LITERATURE Driescu Science and philosophy of the organism, vol. 1. Hincenretner, Hetnricn 1915-16 Uber Hyperphalangea des Daumen. Ant. Anz., Bd. 48, 8. 565. Jurcif£, F. 1906 Ein Fall von Hyperphalangie beider Daumen. Lagenbeck, Arch, f. Klin, Chir. Bd. 80, 8. 562. Minoura, Mirsvo 1910 Ein Beitrag zur Kenntnis ‘der Missbildungen an dem Extremititen. Inaug. Diss. Miinchen. Prentiss, C. W. 1903 Polydactylism in man and the domestic animals with special reference to digital variations in swine. Bull. Mus. Comp. Zool., Harvard, vol. 40, no. 6. Sauzer, Hans 1897-98 Zwei Fiillen von dreigliedrigen Daumen. Ant. Anz., Bd, 14, S. 124. Srreve, H. 1915-16 Uber Hyperphalangie des Daumens. Ant. Anz., Bd. 48, S. 565, . ne rs : , a _ , 7 ee ( ate MS, Aig FART . 1S ee e . vty he ‘ req oe or 7 . ‘ of op Wa eae 7 lade ye : we @ ges hs af), ae | dy ME iyltks ab ay a Tey uf 1 bp a + rile ib? Gihi ts at i ha arr Gr =a d Boba! A aT , Sap ) é a han Rs a We * “jit ve gis = ins 5 o, Jd A - , 2 “ im. aff =. on) . €; eked, 13% oy bisvpe@ ‘a te, cua: she cen sais 0 hh. ee ee of, cs eer ALU the’ tf ee 7 : or ‘ “" he ‘ toe § ren ni “ ae a ate At ive a > eer rf F wr, wiv in ted uae ak yet i eS ab tae We b4 De aren ay ih es ¢ -aaggeclael eeaiaae PP wwe Oren he x Tes Lb Ps ee ei x 36 Wie eee iM? ih is ote alten thon Le eae : 3 Sa ie RECENT BOOKS History aNp BiBLioGRAPHY OF ANATOMIC ILLUSTRATION, in its relation to anatomic science and the Graphic Arts, by Ludwig Choulant, translated and edited with notes and a biography by Mortimer Frank, B.S., M.D., 436 pages, illustrated, The University of Chicago Press, Chicago, 1920. A Lasoratory ManvuaL ANp Text-Book or Empryotocy, by Charles W. Prentiss, Late Professor of Microscopic Anatomy, Northwestern University Medi- cal School, Chicago. Revised and rewritten by Leslie B. Arey, Professor of Microscopic Anatomy; Third edition, enlarged, octavo, 412 pages, 388 illustra- tions, many in color. Philadelphia and London, W. B. Saunders Company, 1920. Cloth, $5.50. Tue Form aNnp FuNcTIONS OF THE CENTRAL NERVOUS SysTeM, an introduction to the study of nervous diseases, by Frederick Tilney, M.D., Ph.D., and Henry Alsop Riley, A.M., M.D. Foreword by George S. Huntington, Se.D., M.D.; 1020 pages, 763 illustrations of which 56 are in colors; New York, Paul B. Hoeber, 1921. $12.00. Tue GrowrH AND SHEDDING OF THE ANTLER OF THE DeeER; the histological phenomena and their relation to the growth of bone, by William Macewen, F.R.S., illustrated, 110 pages, Glasgow, Maclehose, Jackson & Co., 1920, 10 s. 6 p. Tue PsycuoLocy or Funcrionat Nevrosss, by. H. L. Hollingsworth, Asso- ciate Professor of Psychology, Columbia University, 260 pages, D. Appleton and Company, New York, 1920. On BonEFoRMATION, its relation to tension and pressure, by Dr. Murk Jansen, Illustrated, 114 pages, Longmans, Green and Co., London and New York, 1920. $7.50. Tue FUNDAMENTALS oF Human Anatomy, including its borderland districts from the view point of a practitioner, by Marsh Pitzman, A.B., M.D., 101 illus- trations, 356 pages, St. Louis, C. V. Mosby Company, 1920. $4.00. Aw InrRopucTION To THE Stupy or Cyrouoey, by L. Doncaster, Se.D.,F.R.S., Cambridge University Press, Illustrated, 280 pages, Cambridge, England (G.P. Putnam’s Sons, 2 West 45th Street, New York). 1920. THE ANATOMICAL RECORD, VOL, 20, NO. 4 Mancn, 1921 Resumen por la autora, Helen Dean King. The Wistar Institute of Anatomy and Biology. Un estudio comparativo de la mortalidad durante el nacimiento en la rata albina y en el hombre. Los datos reunidos durante un periodo de cinco afios demuestran que en un total de 31,670 ratas albinas recién nacidas, 415, o sea el 1.3 por ciento, nacieron muertas. Concediendo que hay probablemente error en estos cdleulos, la mortalidad normal durante el nacimiento en la rata albina es de unos 2 por ciento, esto es la mitad de la misma mortalidad en el hombre. En ambas especies la relacion normal de los individuos nacidos con vida es préximamente de unos 105.5 machos por cada 100 hembras; en los nacidos muertos esta relacién aumenta hasta ser de 130 machos por cada 100 hembras. La mortalidad postnatal es un poco mayor que la mortalidad durante el nacimiento tanto en la rata como en el hombre. Las causas a que debe atribuirse cerca de la mitad de los nacimientos de individuos muertos en el hombre, esto es las enfermedades infecciosas, implantacién defectuosa y obstruc- cién mecdnica durante el nacimiento, al parecer no influyen sobre la mortalidad natal de la rata. Las causas principales de tal mortalidad en dicho animal parecen ser los factores que afectan la nutricién del feto, tales como la edad y condicién fisica de la madre, lactancia y nimero de individuos de la erfa. Tanto en la rata como en el hombre, el feto macho parece ser intrinsecamente mds débil que el hembra, y por consiguiente puede ser influfdo adversamente con mis facilidad por las con- diciones inimicas al desarrollo normal. La autora propone una hip6tesis que supone que la diferencia en el vigor constitucional de ambos sexos depende de la estructura diferente de la cromatina en el zigoto macho y en el hembra. Translation by José F. Nonidez Cornell Medical College, New York AUTHOR'S ABSTRACT OF THIS PAPER ISSUED BY THE BIBLIOGRAPHIC SERVICE, DECEMBER 27 A COMPARATIVE STUDY OF THE BIRTH MORTALITY IN THE ALBINO RAT AND IN MAN HELEN DEAN KING The Wistar Institute of Anatomy and Biology Literature dealing with birth statistics for man contains numer- ous references both to the number and to the sex of the stillborn; but in none of this literature, nor in any of the many works coy- ering various phases of animal breeding, is there any detailed information regarding birth mortality in other mammals. It has seemed worth while, therefore, to record the data for stillbirths in the albino rat that have been collected in the course of an extensive series of breeding experiments carried on in the animal colony of The Wistar Institute of Anatomy and Biology. Life processes in the rat accord in many ways with those for man, as Donaldson (’06, ’08, °18) has pointed out, and the data given in the present paper indicate that there is also a close agreement in their normal sex ratio, in their birth mortality, and in the sex proportions of the stillborn. The collection of data regarding the birth mortality in the albino rat was begun June 1, 1913, and carried on uninterruptedly for four years; it was resumed the beginning of June, 1918, and discontinued June 1, 1919. In any investigation of this charac- ter it is essential that all of the individuals in a given litter should be recorded, if the data are to have much statistical value. This necessitates, in the case of the rat, an examination of the litters at birth, or shortly after, since stillborn young left for a longer time in the nest are sometimes destroyed. While it is known that the data for the great majority of litters included in this study are complete, there is a probability that some of the still- born young were omitted from the records, since all litters could not be examined at or close to the time of birth. The magni- tude of the probable error is not great enough, however, to affect 321 322 HELEN DEAN KING the general conclusions that have been drawn, though more exact data might change somewhat the various percentages given. Normally, young rats begin suckling soon after their birth, and as at this time and for some days afterward the skin over the abdomen is semi-transparent, any milk in the intestinal tract is readily seen and is a sure indication that the individual was alive when born. There is, therefore, no difficulty in distinguish- ing the stillborn individuals from those that died later, even though the litter is not examined until a day or two after it is east. Throughout this paper the word ‘stillborn’ is applied only to young rats that lived through the normal gestation period (twenty-one to twenty-three days) and died shortly before or during birth, and the mortality data given are for such individuals only. Only a very few cases of abortion have been found in the course of breeding experiments with the rat extending over a - period of eleven years and comprising many thousands of indi- viduals; none of these are included in the present study. THE NORMAL PERCENTAGE OF STILLBIRTHS During the period in which the birth mortality statistics for the albino rat were being collected, a total of 253 litters were found in which one or more individuals were stillborn. Data for these litters, arranged according to the year in which the records were taken, are given in table 1. The data given in table 1 show that there was considerable variation in the number of stillbirths occurring in different years. Such variation was to be expected, since the total litter production in the colony varied greatly from year to year (table 2). The percentage of stillbirths in the total number of individuals in- volved, however, is remarkably constant for all sets of data, as the range of variation is from 20 to 26.2 per cent only (table 1). Since in each year that records were taken at least one-fifth of the young in a considerable number of litters were dead at birth, it is evident that the mortality was not due to chance, but to some disturbance in the metabolism of the mother that tended to involve the litter as a whole. BIRTH MORTALITY IN THE RAT AND IN MAN 323 In order to show the normal percentage of stillbirths in the entire colony, data for the total litter production during the period that the mortality records were taken are given in table 2. TABLE 1 Data for living and for stillborn young in 258 litters of albino rats. Groups arranged according to the year in which the records were taken LIVING YOUNG STILLBORN YOUNG TOTAL YEAR aoe on phar Number Num ion ont UITTERS | youna | Males |Females oe Males |Females | in total females. females ce wont 1913-1914 29 225 81 99} 81.8] 25 20 | 125.0| 20.0 1914-1915 78 570 222 | 225 | 98.7] 70 53 | 132.1] 21.6 1915-1916 35 289 121; 104/|116.3| 36 28 | 128.6) 22.1 1916-1917 51 339 1385 | 115 | 117.4] 48 41. | WZ |, 26:2 1918-1919 60 394 152 | 148 | 102.8] 55 39 | 141.0] 23.8 253 1,817 711 | 691 | 102.9 | 234 | 181 129.3 | 22.8 = EE ae) ee ee cee eee Dees TABLE 2 Showing the total number of individuals, including the stillborn, that were produced in a colony of albino rats during a period of five years Baden Pathan OF waues | NUMBER PER CENT YEAR Tae or rx MALES | FEMALES v0 100 ere nx | STILLBORN 1913-1914 | 899 | 6,677 | 3,379 | 3,208 | 102.5 45 0.67 1914-1915 945 7,065 3,690 3,375 109.3 123 1.74 1915-1916 | 928 | 6,443 | 3.273 | 3.170 | 103.2 64 0.99 1916-1917 1,023 7,131 3,597 3 534 101.8 89 1.25 ‘1918-1919 625 4 354 2217 2,137 103.7 o4 2.16 4,320 | 31,670 | 16,156 15,514 104.1 415 1 31 As table 2 shows, from 600 to 1000 litters of albino rats were born each year during the period covered by the investigation. The percentage of stillbirths in the total litter production varied considerably in different years, and for the 31,670 births was 1.31 per cent. Assuming, for reasons to be given later, that at most only 8 per cent of the stillbirths that occurred were not recorded, it would appear that the normal birth mortality in the colony, under existing conditions of environment and of nutri- tion, was not greater than 2 per cent. 324 HELEN DEAN KING During the past seventy-five years an extensive literature has appeared dealing with the birth statistics for man in various countries of the world. From the data given in this literature, Nichols (’07) has compiled a table showing the living and the stillbirths throughout the world during the period from 1751 to 1903. In the enormous total of 447,019,579 births recorded, 13,635,986, or 3.04 per cent, were stillbirths. From a statistical standpoint the various sets of data used by Nichols are not of uniform value, since the laws regarding the registration of births vary greatly not only in different countries, but in different sec- tions of the same country (as in the United States), and therefore many of the records are known to be incomplete. The records of stillbirths, especially, are very faulty, partly because in many countries their registration is not required and partly because the data obtained include fetuses aborted at various stages of gesta- tion. With reference to human births, it may be noted, the word ‘stillborn’ is used to designate fetuses that are at least seven months of age when born; fetuses aborted at earlier stage of development are not ordinarily included in birth statistics. More recent series of statistics show a birth mortality for man varying but slightly from that given by Nichols. Thus Auer- bach (’12) states that in over 100,000 births as registered in Budapest, 3.3 per cent were stillbirths, and Terry (’17) has shown that in a total of 449,744 births recorded in Massachusetts during 1910 to 1914 there were 15,911, or 3.2 per cent, of stillbirths. In certain countries in which the laws regarding the registra- tion of births are relatively strict, the percentage of stillbirths is somewhat higher than that given by Nichols. For example, sta- tistics for Prussia during the period from 1872 to 1881 show, ac- cording to Diising (’84), that the stillbirths formed 4.67 per cent of the total of 10,577,478 births; birth statistics for the United States during 1918 show 3.56 per cent of stillbirths in a total of 1,412,283 births (Davis, ’20). The data for human births in one year in selected cities of the United States, as collected by The Children’s Bureau of the U.5. Department of Labor, form a unique and valuable series (Duke, 15; Duncan and Duke, ’17; Allen, 19; Dempsey, 19). Although BIRTH MORTALITY IN THE RAT AND IN MAN 325 the number of births recorded is very small when contrasted with the large numbers given above, the great care taken to make these records as complete as possible gives to the data great statistical value. Birth statistics for four selected cities, as collected by The Children’s Bureau, are given in table 3. TABLE 3 Summary of human births in one year based on data collected by the U. S.Children’s Bureau in selected cities of the United States. 1, Brockton, Mass.; 2, Johns- town, Pa.; 8, Manchester, N. H.; 4, Saginaw, Mich. LIVING YOUNG | STILLBORN YOUNG TOTAL | NUMBER NUMBER | OF MALES or ro 100 BIRTHS | FEMALES { | | | Pe Number} Num- Number oz cant of males | ber of a} ¢ jo males rey sery to 100 | indi- £0100" | aoe females iouae females young 1 1,247 | 105.77 106.13] 37 | 18] 19} 94.73) 2.96 2 1,551 | 110.16 108.40) 88 52) 36) 144.44 5.67 3 1,643 | 101.10 99.74) 79 45) 34) 132.35 4.80 4 1,015 | 107.99 106.92} 34 | 20) 14) 142.85) 3.34 5,456 | 105.96 | 5,218) 2,672) 2,546) 104.94) 238 |135,103) 131.06, 4.36 1 Statistics of births during one year in a fifth city, Waterbury, Conn., have also been published by the Children’s Bureau (Hunter, '18). The data given show a total of 2,654 births of which 3.2 per cent were stillbirths. Sincesex data are given for only 53 of the 86 stillborn young, this series of data isexcluded from table 3. As shown in table 3, the percentage of stillbirths in the various cities concerned varied from 2.96 (Brocton) to 5.67 (Johnstown), and in the total of 5,456 births recorded there were 238, or 4.36 per cent, of stillbirths. - In this series, therefore, the birth mor- tality is considerably higher than that in any series of data previ- ously cited, yet in each of the papers in which the birth statisties are given it is stated that the number of stillbirths recorded is probably too low, owing to the great difficulty experienced in obtaining accurate information regarding such births. It has been estimated that at least 5 per cent of stillbirths are never recorded, even in localities in which the laws regarding their registration are most rigidly enforced. 326 HELEN DEAN KING Although the birth mortality in domestic animals would seem to be a matter of considerable importance to the stock breeder, there are only a few scattered references to it in works dealing with various phases of stock breeding, and practically no data having statistical value are available for analysis. According to Bernoulli (’41), records for Europe covering a period of ten years show that from 10 to 15 per cent of calves were dead at birth. As, however, a very great proportion of these deaths were undoubtedly abortions due to infectious disease, the normal birth mortality among full-term fetuses is yet to be determined. Fairly complete records regarding living foals have been kept in various studs throughout Europe for many years, but data for the stillborn are very meager. Records compiled by Hoffman (’85) show that in a total of 1,556 foals, 87, or 5.6 per cent, were stillborn: Goehlert (’84), quoting Baumeister, states that on the average 6 per cent of all foals are born dead: 4 per cent of these are cases of abortion and 2 per cent are of foals at the end of term. In neither of these papers are any data given that show the sex proportions among the stillborn young. Available evidence thus seems to indicate that in the higher mammals from 2 to 4 per cent of full-term fetuses are dead at birth, and it is probable that at least half of this mortality is due either to disease or to mechanical injury at birth. THE SEX RATIO IN STILLBORN YOUNG It is a matter of considerable interest whether the sex ratio, i.e., the number of males to each 100 females, in the stillborn is the same as that in the living young. For if there is a pronounced and constant difference between these two ratios, there must be some disparity between the sexes that is an important factor in the birth mortality. ; In order to make possible a comparison between the sex ratio for the living and that for the stillborn young of the albino rat, it is necessary to ascertain the sex ratio that is normal for the species. Cuénot (’99) gives 105.6 males to 100 females as the sex ratio in thirty litters of albino rats; records for over 1000 litters of stock Albinos, as collected by King and Stotsenburg (’15), BIRTH MORTALITY IN THE RAT AND IN MAN 327 show a sex ratio of 107.5 males to 100 females; while the data as given in table 2 of the present paper indicate a sex ratio of 104.1 males to 100 females in a total of 31,670 births. The normal sex ratio for any species can be obtained only by ascertaining the sex proportions among all of the offspring of a considerable number of females kept under favorable conditions of environment and of nutrition during the entire period of their reproductive activity. None of the sex ratios for the albino rat as given above can, therefore, properly be taken as the norm, since none of them are based on completes series of data. Records covering the complete breeding history of a number of stock albino females have recently been obtained, however, and they show that the sex ratio in the newborn, including those dead at birth, is about 107 males to 100 females.” This ratio, therefore, is the one that will be taken as the norm for comparison with the sex ratio in the stillborn. On referring to table 1 it is found that in each year that mor- tality data for the albino rat were recorded there was a very great excess of males among the stillborn. While the number of stillbirths in any year was relatively small, the fact that in each set of records the sex ratio varies from the norm in the same direction and to a very considerable degree adds materially to the value of the data. In the total of 415 stillbirths recorded the sex ratio was 129.3 males to 100 females. This ratio is 26 points above that for the living young in the litters concerned, and as it is 22 points higher than the sex ratio taken as the norm (107 males to 100 females) the deviation is much too great to be considered as within the limits of normal variation. Granting that the records for stillbirths are incomplete, there is no reason to suppose that the sex ratio in the unrecorded stillborn would differ materially from that for the recorded stillborn as given in table 1. The evidence at hand, therefore, indicates that in the rat the mortality at birth is far greater among the male than among the female young. According to Rauber (’00), as early as the year 1660 Graunt showed that more boys than girls were born in the city of London, and this finding has been confirmed by practically every collector 328 HELEN DEAN KING of human birth statistics since that time. Nichols’ very compre- hensive table of birth statistics, to which reference has already been made, shows a sex ratio of 105.5 males to 100 females in over four hundred million living births. More recent data give practically this same ratio: thus data for 171,297 living births of white and colored children in Cuba during the period from 1904 to 1906, as given by Heape (’09), show a ratio of 105.46 chusetts from 1910 to 1914 the sex ratio is 105.41 males to 100 females (Terry, ’17). Statistical evidence from many different sources thus seems to warrant the conclusion that in all civilized countries of the world there is an excess of males among the living young; the ratio which may be considered as the norm being about 105.5 males to 100 females. This ratio, as several investi- gators have pointed out, is remarkably constant and is main- tained ‘through periods of war and of peace, of famine and of plenty, and under a great variety of racial and of climatic condi- tions; the variations, as a rule, being not greater than one per cent”’ (Pike, ’07). Available statistics for the sex of stillborn children are admit- tedly very incomplete, yet millions of such births have been recorded and they invariably show a fairly uniform sex ratio that differs in a marked degree from the sex ratio which is the norm for the living young. A few series of investigations may be cited to indicate the trend of such statistics in general. In the 13,635,986 stillbirths compiled by Nichols there were 131.6 males to each 100 females, the range of variation in the number of males being from 130 to 140 in the great majority of cases. In the records for stillbirths in various countries of Europe, as tabulated by Lewis and Lewis (’06), the number of males to 100 females varies from 120 to 170, with the average around 130; Heape’s (’09) data for Cuban births shows a sex ratio of 144.45 males to 100 females among the stillborn, while Hirsch (713) gives 127.9 as the number of males to 100 females in the stillborn young recorded in Germany during 1908 to 1909; and, finally, the birth statistics of the United States for the year 1918 indicate a sex ratio of 137.1 males to 100 females among the stillborn (Davis, 20). BIRTH MORTALITY IN THE RAT AND IN MAN 329 All of the various series of records given above show that the sex ratio in the stillborn is much higher than that in the living young, and sex statistics for aborted fetuses indicate that the excess of boys becomes greater the earlier the month of preg- nancy in which the fetus dies (Rauber, ’00; Nichols, ’07; Auer- bach, ’12; Carvallo, 712). This latter fact is of great importance, since it indicates that one, at least, of the chief causes for the ex- cessive mortality among males at birth must be sought in condi- tions that exist in early rather than in late stages of gestation. In 1841 Bernoulli called attention to the fact that the sex ratio at birth is not the ratio in which the young are conceived, and he concluded that the true sex ratio for man is about 108.2 males to 100 females. This ratio is practically the same as the ‘primary’ sex ratio recently calculated by Jendrassik (’11) and by Schultz (18). The fact that in man the sexes are very evidently not conceived in equal numbers is a decided stumbling-block in the way of any theory of sex determination that postulates chance as the chief factor in deciding whether a given ovum shall become male or female. Morgan (’19) has recently offered the following explanation for the constant sex ratio in man: Since male babies die oftener than females, the difference has been said to be an ‘adaptation,’ with the implication that it calls for no further explanation. Several possible solutions suggest themselves. The male-producing sperm bearing the sex-chromosome may more frequently develop abnormally than. the female-producing sperm. Again, since the spermatozoa must, by their own activity, travel the entire length of the oviduct to reach the egg as it enters the tube, the greater size or weight of the female-producing sperm may give a slight advantage to the male-producing sperm in the long trip up the tube. This would lead to an excess of males. Since there is no evidence at present that one kind of spermato- zoa is more active or more inclined to be abnormal than the other, it must be admitted that the above explanation for the male excess in human offspring is not an entirely satisfactory one. A comparison of the sex ratios found in the newborn of the rat with the corresponding ones for man show that they agree closely in all cases. The sex ratio that is normal for the living young at birth is practically the same in both species, being about 105.5 330 HELEN DEAN KING males to 100 females; in both species, also, the sex ratio in the stillborn is much higher than that in the living young, averaging about 130 males to 100 females. This striking similarity in the sex ratios of two such widely separated mammals as the rat and man is a matter of considerable theoretical interest, and it may have a practical bearing as well, since through carefully controlled experiments on the lower form it may be possible to obtain information that will help to check the appalling birth mortality among human offspring. Although a considerable body of statistics has been collected by Diising (’84) and by Wilckens (’86), among others, regarding the normal sex ratio in domestic animals, practically no informa- tion is available concerning the sex proportions in the stillborn. In fact, the only reference to this subject that I have been able to find is in a paper by Goehlert (’82) which deals chiefly with the inheritance of coat color in the horse. Goehlert states that in 135,826 living foals born in various studs throughout Europe the sex ratio was 96.57 males to 100 females. Then follows this significant statement: ‘‘ Derselbe steigert sich bei den todtgebor- enen auf 106 bis 107 Hengst gegen 100 Stutenfohlen.”” The data on which the above statement is based are not given, but if they are extensive and accurate enough to have statistical value, they indicate that the sex ratio in stillborn foals is some 10 points higher than that in living foals. Thus in man, in the rat, and in the horse, the only mammals for which data are at present available, the birth mortality is apparently far greater among the male than among the female young. It is not improbable that future investigations will show that this condition is characteristic of the Mammalia generally. SEASONAL VARIATIONS IN THE PERCENTAGE OF STILLBIRTHS It has been claimed by Diising (’84) that seasonal variations in temperature, through their action on nutritive conditions, affect not only the sex of developing fetuses, but the percentage of stillbirths as well. The desirability of recording data for stillborn rats according to the month of the year in which birth occurred was not realized BIRTH MORTALITY IN THE RAT AND IN MAN 331 when this investigation was begun, consequently only the data collected during the last year can be grouped by seasons as shown in table 4. Stillbirths were recorded in the colony during every month of the year, the smallest number (3) being found in May, the largest (14) in September. On grouping the data as shown in table 4, it is seen that the 94 stillbirths were very evenly distributed throughout the different seasons, the variation in number being from 21 (spring) to 25 (autumn). The percentage of stillbirths in the total litter production, however, shows a wide range of variation in different seasons, being nearly twice as great in TABLE 4 Showing the percentage of stillbirths in the albino rat colony from June 1, 1918, to June 1, 1919. Data arranged according to the season of the year in which birth occurred PERCENTAGE TOTAL TOTAL NUMBER STILLBIRTHS SEASON NUMBER OF | NUMBER OF or IN TOTAL LITTERS YOUNG STILLBIRTHS | NUMBER OF YOUNG Spring (March to May)............. 183 1,349 24 1.78 Summer (June to August)......... 166 1,134 21 1.85 Autumn (September to November). . 120 821 25 3.04 Winter (December to February).... 156 1,050 24 2.28 625 4 354 oF 2.16 autumn (3.04) as in summer (1.78). The data given in table 4 are, of course, too few to have much statistical value, but they seem to indicate that the percentage of stillbirths tends to vary somewhat with the season, reaching its highest point in the au- tumn months. Lacking adequate means of heat regulation, rats suffer severely from high temperature, and the young born late in summer and in the autumn are, as a rule, inferior to those born at other seasons as regards their power of growth, resistance to disease, fertility, and longevity. It is not surprising, there- fore, to find that this lowering of the physical tone of the animals at a definite season of the year is followed by an increase in the birth mortality. 332 HELEN DEAN KING From an analysis of the data for over ten million births occur- ring in Prussia from 1872 to 1881, Diising (’84) concludes that ‘bei den Kindern, welche im Anfang des Jahres erzeugt und im Herbst geboren werden, zeigen sich die wenigsten (3.6 per cent), dagegen bei denen, welche im Friihjahr gezeugt und in Winter geboren werden, die meisten tot-geburten (4.4 per cent).’’ Other groups of statistics for human births do not support Diising’s conclusions, however, Thus, data compiled by Davis (’20) show that in the birth registration area of the United States during 1918 the lowest percentage of stillbirths occurred during the summer (3.07 per cent), and the highest in the autumn (3.79 per cent); while birth statistics for the city of Philadelphia covering a period of ten years (Sozinskey, ’85) and also those for Boston during 1891 to 1910 (Whipple, ’19) indicate no appreciable varia- tion in therate of stillbirths during different seasons of the year. From available evidence it would appear that the birth mor- tality in man is but little influenced by the season of the year in which either conception or birth occurs. Since man has a highly developed mechanism for heat regulation, moderate changes of temperature have very little effect on body metabolism and therefore cannot, under ordinary circumstances, influence the nutrition of the fetus, as Diising claims. POSTNATAL MORTALITY Since deaths that occur among the young within a few days after birth are traceable, in many cases, to prenatal causes that are responsible for a certain proportion of stillbirths, a brief consideration of postnatal mortality is included in the present paper. Little exact information is available, as yet, regarding the mortality among young rats during the week after birth. The number of such deaths in any large colony is considerable, but what proportion of them is due to prenatal causes cannot be determined, since a great part of such mortality is always due to causes that are purely accidental, such as smothering of the young by the crowding of adults into the nest when they are cold or BIRTH MORTALITY IN THE RAT AND IN MAN 333 frightened and death from exposure or starvation when the young leave the nest and are not carried back by the mother. Records kept from June 1, 1918, to June 1, 1919, show that ninety-eight rats died within three days after birth from causes that were undetermined. As during this year 4,250 living young were born in the colony, the postnatal mortality was 2.3 per cent, or slightly greater than the birth mortality during the same period (table 2), Although the great majority of these deaths were undoubtedly accidental, some of them were unquestionably due to prenatal causes that so affected the constitutional vigor of the individual that death was inevitable. Occasionally litters are cast in which one or more of the members are very much under normal size. These small individuals are the so-called ‘runts,’ which are frequently found among multiparous mam- mals, and since they are usually unable to compete with the larger and more vigorous individuals of the litter in their efforts to obtain food, they generally die within a few days after birth. Under very favorable conditions some of these undersized indi- viduals are able to survive and to reach maturity, but they never attain the size of the normal members of the litter and they are usually sterile (King, 16). Since runts are found most fre- quently in very large litters cast by young females and in litters cast by females that are not in good physical condition, they are evidently individuals with relatively low initial vitality that were subjected to conditions inimical to growth during the intra- uterine period; the weaker among them die soon after birth, those that survive are among the physically unfit that generally ‘drop out’ at a relatively early age. Among the 98 young recorded as dying shortly after birth there were 42 males and 56 females, or a sex ratio of 75 males to 100 females as contrasted with a sex ratio of 141 males to 100 females in the stillborn young found during the same period (table 1). The marked difference between these two ratios is readily explicable. Factors responsible for the great excess of males among the stillborn can act only to a very limited extent in influ- encing the sex ratio in the young that die after birth, and post- natal mortality due chiefly to accidental causes might be ex- 334 HELEN DEAN KING pected to take a heavier toll from the females, since at birth the females are somewhat smaller, as a rule, than the males (Donald- son, ’06; Jackson, 713; King, 715). The question of postnatal mortality among human offspring involves so many different factors that an adequate consideration of the subject cannot be attempted here. The many investiga- tions that have been made show that the mortality is very high during the first month after birth, averaging about 5 per cent of all young. About one-fourth of these deaths, it has been esti- mated, are due to improper care or to disease, the remaining can be attributed to premature birth, injuries at birth, or to congenital debility (Ashby, ’15; Hunter, ’18; Eastman, ’19; Dempsey, ’19). Sex statistics for infants dying under one year of age, as col- lected by a number of investigators in various countries (Diising, ’84; Rauber, ’00; Prinzing, ’06; Nichols, ’07; Dutton, ’10; Pinard et Magnan, ’13; Kroon, ’17; Ashby, 715; Davis, ’18, ’19, ete.), all show that infant mortality is considerably greater among boys than among girls, and that, while it varies considerably in dif- ferent localities and under different conditions, on the average about 120 boys die to each 100 girls. A comparison of the findings for the rat with those for man shows that in both forms the postnatal mortality is somewhat higher than the birth mortality; in the rat this mortality is chiefly due to accidental causes that seemingly tend to kill more females than males, while in man infant mortality is traceable in many cases to ‘congenital debility’ which is apparently far more fatal to males than to females. CAUSES OF BIRTH MORTALITY Barring accidents, there are six leading causes to one or an- other of which practically all stillbirths in mammals can be ascribed: 1) malposition of the fetus leading to abnormal devel- opment; 2) infectious disease; 3) mechanical obstruction to birth, . including size of the fetus; 4) physical condition of the mother; 5) age of the mother; 6) congenital debility. The part played by these various factors in the birth mortality in the rat and in man will be discussed briefly in the following sections. BIRTH MORTALITY IN THE RAT AND IN MAN 335 a. Malposition of the fetus and disease as causes of birth mortality Faulty implantation is responsible for the abnormal develop- ment of many ova in the rat (Huber, ’15), but these ova, as a rule, die at an early stage and are absorbed in situ. Little is known, as yet, regarding the death in utero of older embryos. The examination of a number of gravid females indicates that this phenomenon is not as common in the rat as it is in many other multiparous mammals (Stahl and Henneberg, 02; Hammond, 14). So-called ‘monsters,’ which arise through faulty implanta- tion and consequent inadequate nutrition of the embryo, com- prise about 1 per cent of all human fetuses at birth (Mall, ’08), but they are very rare among newborn rats. In the course of an examination of over 50,000 young rats I have found but four such fetuses, and in all of these the body appeared perfectly normal, but the head was hydrocephalic. Infectious diseases are responsible for an appalling number of deaths among human offspring and among the young of cattle, but no cases are known, as yet, in which stillbirths in the rat could be ascribed to this cause. Neither the rat scourge, so-called ‘pneumonia,’ nor other diseases common to the rat are trans- mitted to the fetus as far as is known. From the evidence at hand, therefore, infectious disease can be eliminated as a cause of stillbirth in the rat, though illness of the mother, as will be shown later, is a potent factor in birth mortality. b. The size of the fetus as a cause of birth mortality Since the size of the fetus is an important factor in human birth mortality (Diising ’84; Nichols, 07; Dutton, 10; Hirsch, ’13), it is conceivable that this factor may also play a réle in the birth mortality in the rat. The following series of observations was made to determine this point. Fifty-nine litters of rats, in which one or more members were stillborn, were obtained at birth. Each of the young rats was taken from the mother as soon as it was east, the placenta was removed, and the body weight taken immediately. Data re- garding the age and general physical condition of the mother at THER ANATOMICAL RECORD, VOL. 20, No. 4 336 HELEN DEAN KING the time of parturition were also recorded, since these factors had to be taken into account as possible causes of birth mortality. The body weight records for the 306 living and for the 137 stillborn young in these fifty-nine litters are shown in table 5. For purposes of later analysis the data are arranged in three groups according to the physical condition of the mother at the time of parturition. TABLE 5 Sex and body-weight data for living and for stillborn young in fifty-nine litters of albino rats. Groups arranged according to the physical condition of the mother at the time of parturition LIVING YOUNG STILLBORN YOUNG PHYSICAL Num- | Average areas Number | 4¥erage Bthieia 2 Percent- CONDITION OF ber of body aight of body Bl agente MOTHER indi-_ |, weight all | 1, -cest in- |individuals|, Ye@htall | igrgest in- | born in P| viduals |individuals| ‘Givi duals individuals dividuals |total num- > ber of ° SESE EE EEE | S ET) | PPE Ps ef) gms.|gms.|}gms.|} gms. gms.| gms.|gms.| gms. 1 | Good 68| 51/4.57/4.28/4 91\4 52} 21 | 21 |4.20/3.75/4.50)4.11) 26.1 2 | Poor 43) 60/4 .24/4.17/4.45|4.42| 46 | 28 |4.15)/4.08/4.40)4.31) 41.8 3 | Good, but fe- male young] 43) 41/4.12)3 .84/4.53/4.40} 12 | 9 |8.56/3.80/3.85/3.85} 20.0 154/152/4 41/4. 13/4.66)4.39) 79 | 58 /4.11/3.81)/4.36)/3.99) 30.9 In table 5 the final averages, computed from individual not from grouped data, confirm the findings of Donaldson (’06), of Jackson (713), and of King (715), that in the rat the living male is heavier at birth than the living female. They show, also, that this same relation is found among the stillborn; the difference between the body weights of the two sexes averaging about 0.30 - gram in each case. In each of the three groups given in table 5, the living young, both males and females, have a heavier birth weight than the stillborn young, the final averages indicating a difference of 0.30 gram for each sex. Obviously the body-weight relations between the living and the stillborn young would be just the reverse of that shown above if the size of the individual is a determining cause of birth mortality. When the average body weights for BIRTH MORTALITY IN THE RAT AND IN MAN 337 the largest of the living and the largest of the stillborn in each group are compared, the result shows conclusively that the size of the fetus is not a cause of death at birth, since in all three groups the average body weight of the largest living individual of both sexes exceeds that of the largest stillborn individual in the corresponding group. In this instance, also, the final averages show a difference of 0.30 gram in favor of the living young. In man multiple births are the exception, not the rule as in the rat, so in this respect conditions in these two species are radically different. It is not so much the weight of the fetus as the size of the head that is responsible for the death of many infants, particularly boys. The deaths from this cause and those due to other forms of mechanical obstruction to birth comprise about 10 per cent of all human stillbirths, according to various observers. The data given in table 5 show that the stillbirths formed 30.9 per cent of the total of 448 births in fifty-nine litters of albino rats. In collecting these data there was no error, since the litters were obtained at the time of birth and all of the young recorded. In the total of 253 litters containing stillborn young that were ob- tained during a period of five years, the birth mortality among 1817 individuals, as registered, was 22.8 per cent (table 1). The difference between these two sets of data would seem to indicate that at most 8 per cent of the stillbirths in the colony were not recorded. ‘This error is not sufficiently large to invalidate any of the conclusions drawn from the records as they stand. c. The physical condition of the mother as a cause of birth mortality It requires but little experience in the handling of albino rats to determine from the general appearance of an animal whether or not it is in good physical condition. Alert animals of large size, having clear eyes and thick, glossy hair, are usually in excel- lent condition and free from disease. On the other hand, la- bored breathing, rough hair, dark red eyes, sluggish movements, and relatively light body weight are all evidences of poor physical condition and generally indicate that the animal is in an advanced stage of ‘pneumonia.’ 338 HELEN DEAN KING Table 6 shows the age, body weight, and general physical con- dition of the fifty-nine albino females that gave birth to the young whose body-weight data are given in table 5. The first group in table 6 comprises twenty females that were apparently in good physical condition at the time of parturition, as was indicated not only by their general appearance and be- havior, but also by the fact that they weighed, on the average, over 15 grams more than the ‘standard’ body weight for breeding females of the same age (Donaldson, ’15). The average body weights of their young at birth exceeded those of the young cast by females in poor condition (cf. group 1 and group 2; table 5), thus adding more evidence that ‘‘rats in good physical TABLE 6 Data regarding the age, body weight, and general physical condition of the fifty-nine female albino rats that cast the litters recorded in table 6 . STANDARD BODY WEIGHT AVERAGE AGE Jenene wcnaen FOR AVERAGE GROUP GENERAL PHYSICAL NUMBER OF FEMALES OF FEMALES AGE OF CONDITION OF FEMALES OF FEMALES AT Ar FEMALES AT PARTURITION aie PARTURITION PARTURITION (DONALDSON, "15) days gms. gms. 1 Good 20 202 224.4 209.1 2 Poor 26 244 190.7 220.0 3 Good; but female very young 13 99 143.7 146.2 condition bear young with a birth weight considerably above that of the young cast by females in poor condition” (King, ’15). Each female in this group gave birth to a litter that contained, on the average, two stillborn to six living young (table 5). Since these stillbirths cannot be ascribed either to mechanical obstruc- tion to birth, to abnormal development, nor to infectious disease, it would appear that they must have been caused by some other prenatal condition that adversely affected the vitality of the young. Examining the history of the mothers, as kept on record cards, it was found that five of the females in this group were nursing young at the time that the litter containing stillborn young was BIRTH MORTALITY IN THE RAT AND IN MAN 339 cast; eight of the females gave birth to very large litters contain- ing ten or more members; three females were over fifteen months of age at the time of parturition. No reason can be assigned for the presence of stillborn young among the offspring of the re- maining four females in this group. It is possible, perhaps, that these females were in early stages of ‘pneumonia’ which had not as yet altered either their general appearance or their body weight, but had already affected their body metabolism in such a way as to adversely influence the development of the fetal young. The second group in table 6 comprises twenty-six females that were obviously in bad physical condition at the time that their litters were cast. These females were, on the average, some 30 grams under the ‘standard’ body weight for breeding females of the same age, and the birth weights of their young were very low (table 5). It is of interest to note that the percentage of stillbirths in the total number of young cast by these females was relatively very high (ef. group 1 and group 2; table 5). The majority of the females in this group were obviously suffering from ‘pneumonia;’ three of them were in such an advanced stage of the disease that they had to be killed as soon as the litter was cast. d. The age of the mother as a factor ,in birth mortality It has already been shown that litter size in the albino rat is influenced to a considerable extent by the age of the mother (Slonaker, 712; King, ’16 a), and it is possible that the viability of the young at birth may also be affected by this same factor. As already noted, three of the females in the first group of table 6 were over fifteen months of age when casting a litter that contained stillborn young. These females appeared to be in good physical condition, yet their litters were very small, and seven of the eleven young cast were dead at birth. The third group of table 6 comprised thirteen females that had an average age of only ninety-nine days when casting their first litter. Al- though each of these females was seemingly in good health, twenty-one in the total of 105 young were stillborn (table 5). 340 HELEN DEAN KING Since none of the females in these two groups showed any evi- dence of disease at the time of parturition, it is probable that the age of the mother, and not incipient ‘pneumonia,’ was the chief factor responsible for the high birth mortality in their young. ‘The age of eighteen months marks approximately the end of the reproductive activity of the albino female, and toward its close, as at its beginning, there seems to be a strong tendency for the females to cast fewer individuals in a litter and a relatively greater proportion of stillborn young. This phase of the eae will be discussed later. In considering the causes responsible for stillbirths among human ofispring, the age of the mother is a factor that is usually ignored or assigned a very minor réle. Various series of reliable statistics, however, indicate that the birth mortality is relatively high in children of very young and of very old mothers, so evi- dently the age factor has greater influence in this respect than is generally assumed. The trend of statistical evidence on this point is shown by the following examples. Whipple’s (’19) analysis of the birth statistics for the city of Boston during the period from 1891 to 1910 shows that: “‘The percentage of still- births arranged according to the age of the mother gave the very high percentage of 11.1 per cent for mothers under 20 years of age, 4 per cent for age group 20-24, 5.1 for 25-29 years, 4.4 for 30-39 years, and 3.3 for ages over 40.” Far more comprehensive data regarding the effect of the age of the mother on birth mortality among the young are given by Davis (’20) in his study of the births in the registration area of the United States during the year 1918. In a total of 1,372,329 births in which the age of the mother was ascertained, there were 46,122 stillbirths. The percentage of stillbirths was 3.9 for mothers under twenty years of age, 3.2 per cent for mothers from twenty to thirty-nine years, and 5.4 per cent for mothers over forty. This study indicates that the percentage of stillbirths is much higher in children born to mothers at the beginning and at the end of the reproductive period, and its findings are con- firmed by the birth statistics gathered by The Children’s Bureau (Duke, 715; Duncan and Duke, 717; Allen, ’19; Dempsey, 719), BIRTH MORTALITY IN THE RAT AND IN MAN 341 which have already been given in table 3 of the present paper. They are shown again in table 7, arranged according to the age of the mother at the time that the birth of her child occurred. It will be noted that table 3 gives a total of 5,456 births, while table 7 registers only 5,452 births. This discrepancy is due to the fact that in four cases the age of the mother was not ascertained. Nearly 90 per cent of the births registered in table 7 were those to women between twenty and thirty-nine years of age, the re- maining 10 per cent were evenly divided between women that were under twenty and over forty. As this is about the normal distribution of births relative to the age of the mothers, a com- parison of the percentages of stillbirths as given seems permissible. TABLE 7 Data for human births, collected by the U. 8. Children’s Bureau (table 3), arranged according to the age of the mother at the time of parturition PER CENT ' | S MOTHER 8S AGE TOTAL NUMBER LIVING BIRTHS STILLBIRTHS STILLBIRTHS IN IN YEARS OF BIRTHS TOTAL NUMBER OF BIRTHS Under 20 282 263 19 6.95 20 to 39 4,882 4,683 199 4.07 40 and over 288 268 20 6.94 5,452 5,214 238 4.36 Table 7 shows clearly that in this set of records, as in those given by Whipple and by Davis, the percentage of stillbirths is correlated with the age of the mother. In table 7 the stillbirths formed only 4.07 per cent of all births to women at the zenith of the child-bearing period, while they were increased to nearly 7 per cent in the births to women at the extremes of the reproduc- tive period. When the data in table 7 are arranged according to the order of the birth, as is shown in each of the papers in which the sep- arate sets of data are given, it is found that the percentage of stillbirths is higher for the first births and for those after the sixth than for the intermediate births. A series of birth statisties arranged in this manner is, of necessity, an age series, and it is 342 HELEN DEAN KING more probable that the observed variations in the percentage of stillbirths depend on the age factor rather than on the number of the pregnancy. It has been claimed that the high birth mortality in children of very young mothers is due chiefly to the mother’s ignorance of the proper hygienic laws that should be observed by pregnant women. ‘This explanation cannot be offered to account for the increase in the percentage of stillbirths among the children of women over forty, however, since births at this age are rarely those of the first pregnancy. It seems probable that both at the beginning and at the end of the reproductive period physiological conditions incident to age are responsible in great part for the high birth mortality among the children born at this time. e. Congenital debility as a cause of birth mortality Stillbirths among human offspring not traceable to a well- defined cause are generally ascribed to ‘congenital debility,’ this term being used to indicate a lack of sufficient vitality in the fetus to render postnatal existence possible. Various series of investigations show that a very considerable proportion of still- births are attributed to this cause. For example, in 201 cases of stillbirths at term studied by Brothers (’96), over 50 per cent were classed as due to ‘congenital debility,’ while Waldvogel’s (’13) studies led to a similar conclusion. In the sense in which the term ‘congenital debility’ is used above, practically all stillbirths in the rat might properly be grouped under this heading, since in all cases so far found impaired vitality of the fetal young was seemingly the direct cause of the birth mortality; the underlying cause is discussed in the following section. GENERAL DISCUSSION This study has shown that in two important respects the sta- tistics for the birth mortality in the albino rat accord in a most striking manner with those for man: 1) the sex ratio in the living young at birth is practically the same in both forms (about 105.5 BIRTH MORTALITY IN THE RAT AND IN MAN 343 males to 100 females) ; 2) the great excess of males among human stillborn finds its parallel in the high sex ratio which charac- terizes the stillborn of the rat (129 males to 100 females). In one respect only the birth records for these two forms do not agree. The normal percentage of stillbirths in human offspring (4 to 5 per cent) is at least twice that in the albino rat (table 2). This difference, however, is readily explicable. Factors which are responsible for about one-half of all human stillbirths, i.e., mechanical obstruction to birth, accidents, faulty implantation, and infectious disease, ordinarily play little, if any, part in the birth mortality in the rat. If stillbirths due to these causes are eliminated, the birth mortality among human offspring falls to about 2 per cent, which is close to the percentage of stillbirths which is seemingly normal for the albino rat when large numbers of breeding animals are kept under fairly uniform conditions of environment and of nutrition. The stillbirths in man which thus seem comparable to those in the rat, are those that, in gen- eral, are attributed to ‘congenital debility,’ this term, as already stated, being used to indicate that the fetus possesses such a low state of vitality at the end of term that it is incapable of inde- pendent existence. From the evidence at hand the great pro- portion of stillbirths in the rat can be attributed to the same cause. The question at once arises as to the cause of this impaired vitality in the fetus and whether it is possible to control it so that the percentage of stillbirths will be materially decreased. If we consider those cases in the albino rat in which the stillborn young were obtained at the time of birth and the age and physical condition of the mothers noted (tables 5 and 6), it is found that the great majority of them occurred in litters of females that were suffering from disease, chiefly ‘pneumonia,’ or in those of females at the extremes of the reproductive period, while in a few cases the litters were very large or were cast by females that were suckling young at the time of parturition. Extensive series of breeding experiments extending over a period of a dozen years and covering the birth of many thousands of rats lead me to believe that practically alt stillbirths in this animal occur under 344 HELEN DEAN KING one or another of these conditions. The one factor which seem- ingly might have affected the vitality of the fetal young in all of these cases is malnutrition. The nutrition of the fetal young is a very complex process, and in its broadest sense it includes the absorption and the assimila- tion of food by the mother as well as its transmission through the placenta to the young. Any factor or physiological condition that adversely affects the normal metabolic processes upon which any phase of embryonic nutrition depends therefore indirectly influences the development of the young and may impair their vitality to a greater or less extent. Let us consider in some detail the effect of the various factors that are apparently responsible for stillbirths in the rat. The rat scourge, ‘pneumonia,’ is a wasting disease, and as such pro- foundly affects all of the normal life processes in an animal affected with it. The living young cast by females having this disease in an advanced stage are usually very small and emaciated at birth, and their vitality is at such a low state that they are difficult to rear even when suckled by a vigorous foster-mother. There can be no question but that the fetal young suffer through- out the entire course of their intra-uterine existence from mal- nutrition, since the illness of the mother must interfere with her power to assimilate food and to transmit it to her offspring. With such a handicap to their normal development, it is not sur- prising that a large proportion of the young are not able to survive at birth. The suckling of young, particularly if the litter is above the norm (seven) in size, is as a rule a severe strain on the nutritive reserve of the mother, as is shown by the fact that she usually loses considerable weight during this period unless she is in excel- lent health and abundantly supplied with food. Not infre- quently a lactating female is also carrying a second litter. If one or both of these litters are large, the amount of food that the mother can assimilate and supply to her young, in addition to her own needs, is inadequate for the proper nutrition of all of the individuals concerned. The result is that the suckling young usually grow very slowly and show every evidence of being un- BIRTH MORTALITY IN THE RAT AND IN MAN 345 derfed, and the gestation period of the fetal young is lengthened from one to several days, owing doubtless to the fact that the implantation of the fertilized ova is delayed (King, 13; Kirk- ham, 716). Here again malnutrition is obviously a factor that impairs the vitality of the fetal young and tends to increase the proportion of stillbirths. A similar explanation can be offered for the presence of stillborn young in litters of exceptionally large size. In these cases the inadequate nutrition of the young is indicated by the fact that all members of the litter are, as a rule, of small size and under normal weight at birth. The fact that the proportion of stillborn young in litters cast by very young and by very old females is markedly greater than that in litters cast by females at the height of their reproductive activity indicates that the age of the mother is a factor of impor- tance in birth mortality. Donaldson (’06) has shown that one year of a rat’s life is equivalent to thirty years of human life. At the age of eighteen months, therefore, a female rat corresponds physiologically to a woman of forty-five years, and it can hardly be a coincidence that this age marks approximately the end of the reproductive activity in both species. The onset of puberty does not, however, correspond as closely in the two forms, since rats breed at three months of age. Age has a profound effect on all of the normal activities of the body, and it is not surprising, therefore, to find that the immaturity of the young mother and the physiological changes in the uterus incident to the approach- ing menopause seemingly inhibit the metabolic processes con- cerned with the nutrition of the fetal young. In such cases the young often suffer from impaired nutrition, and consequently the birth mortality among them is much greater than that among the offspring of females at the height of their reproductive activity. It has been repeatedly demonstrated that a mature, well- developed albino female that is in good physical condition at the time of conception, will, if abundantly supplied with proper food during the entire gestation period, cast a litter containing only living, vigorous young that have relatively heavy birth weights. A special experiment recently made to test this point has given 346 HELEN DEAN KING rather astonishing results. The young cast by a mature female abundantly supplied with rich food -during the gestation and lactating period were twice the normal weight at birth, and at thirty days of age, when weaned, they were over 200 per cent above the average weight of rat at this age. At sixty days of age the males in this litter had an average body weight of 260 grams, which is some 300 per cent above the ‘standard’ weight for males of this age. On the other hand, inadequate feeding of breeding females invariably leads to the production of small litters containing undersized individuals in which there is a high percentage of stillbirths. This fact was fully demonstrated in the early stages of an inbreeding experiment with these animals which has been carried on for some years in our colony (King, 18). Even when the food supply is ample, the present study has shown that in lactating females, in those carrying a very large litter, and in those suffering from disease or breeding at one extreme of the reproductive period, physiological conditions within the body of the mother may adversely influence the vari- ous processes upon which the nutrition of the young depends and thus lead in many cases to the death of a considerable pro- portion of the young at birth. Conditions of human existence are so complex and so artificial in many cases that one would hardly venture to assert that the underlying cause of all cases of ‘congenital debility’ was mal- nutrition of the fetus due to the age or to some abnormal physical condition of the mother, yet the evidence at hand is strongly in favor of such a view. Inadequate nutrition of the young is cer- tainly a potent factor in the birth mortality of the rat, and it probably plays an important réle in the birth mortality of other mammals, including man. The maintenance of pregnant females under environmental and nutritive conditions favorable to the health of the mother and to the adequate nourishment of the fetal young throughout the entire gestation period, not merely near its close, would, therefore, undoubtedly lead to the birth of more vigorous young and to a marked decrease in the number of abortions and of stillbirths. BIRTH MORTALITY IN THE RAT AND IN MAN 347 Whenever large groups of human birth statistics have been analyzed it has been found that the mortality among the males is very high, the sex ratio for the stillborn being at least 25 points higher than that in the living young. This same phenomenon appears also when a large series of birth data for the rat are ex- amined (table 1), and it likewise is present in statistics for the horse, if Goehlert’s (’82) records are reliable. Since the disparity between the sex ratios for the stillborn and those for the living young in these various groups of statistics is fairly constant and much too great to be considered as within the range of normal variation in the sex ratio, there must be some fundamental cause, founded on a difference in the constitution of the male and female organisms, that is responsible for the excessive mortality among the males at birth. Diising (’84) discusses this subject at considerable length, and he concludes that: ‘Die Knaben sterben also wiihrend Fotalle- bens hiufiger als die Miidchen, weil viele derselben sich unter ungiinstigen Ernihrungsverhiltnissen ausbilden, wihrend sie, da sie durchschnittlich schwerer sind, sogar mehr Nahrung bean- spruchen als die leichteren Midchen.” Since from the time that the sexes can be distinguished at about the sixth week of preg- nancy the excess of males among aborted embryos is greater the earlier the age at which abortion occurs (Rauber, 00; Nichols 07; Auerbach, ’12; Carvallo, 712), inadequate nutrition cannot well be considered as the primary cause of the greater mortality among male fetuses in general. A most suggestive hypothesis that may have a very important bearing on this problem has recently been advanced by Lillie (17) in his study of the action of sex hormones in producing the ‘free-martin’ in cattle: ‘It seems probable that the disturbance of the equilibrium that protects the male from the sex hormones of the mother would result in malformations of the male sex characters to a degree commensurate with the extent of the dis- turbance. There is, therefore, here a possible explanation for the greater mortality among male foetuses.’ Our knowledge of the action of sex hormones is as yet too meager to enable us to 348 HELEN DEAN KING advance a definite theory regarding the influence of these factors on fetal mortality. Nichols (’07) states that three explanations are open to con- sideration to account for the heavy mortality among boys at birth ‘‘(a) the initial numerical preponderance of males; (b) the greater proportion of deaths of male fetuses occurring during parturition owing to their larger size; and (c) the intrinsically much greater mortality of males than of females in the earlier period of life, both antenatal and postnatal.’”’ Nichols assigns only a minor role to the first two of the causes enumerated above, and he con- cludes that: Obviously the main cause of the great preponderance of male still- births resolves itself into the question of the comparative mortality or death rate of the male and female sexes during the intrauterine period of existence. . . . . it is therefore obvious that the male constitu- tion is intrinsically weaker, less hardy, and more susceptible to: mor- bific and mortific influences, and has less vitality and resisting power against disease, than the female. The cause of this innate disparity of vitality between the two sexes we do not know; but the fact that it exists, that the antenatal mortality and death rate of males much exceeds that of female fetuses, accounts for the great excess of male over female stillbirths. In the light of the recent researches in heredity it is conceiv- able that the inherent dissimilarity between the sexes as regards their constitutional vigor, which has been discussed in detail by Geddes and Thomson (’01), may have its basis in the germinal structure of the fertilized egg. From the work of Guyer (10) and of von Winiwarter (’12) on the spermatogenesis of man, and of Allen (’18) on the spermatogenesis of the rat, it is known that in both of these mammals the spermatozoa are dimorphic, one kind of spermatozoa having one more chromosome than the other; both kinds of spermatozoa are produced in equal numbers and both kinds, as far as known, are equally functional. The current theory of sex determination postulates that the spermatozoa con- taining the extra, or X-chromosome, are ‘female-producing’ ; those lacking it are ‘male-producing.’ The fertilized ovum that is to develop into a female thus contains two X-chromosomes, while that having only the X-chromosome received from the mother BIRTH MORTALITY IN THE RAT AND IN MAN 349 develops into a male. May not the difference in the constitu- tional vigor of the two sexes depend, in some way, upon the fact that the chromatin content of the female ovum is greater than than of the male ovum? One might suggest, perhaps, that the excess of chromatin brought into the egg by the ‘female-produc- ing’ spermatozoan influences the ensuing interaction of the chro- matin and the cytoplasm in such a way that the embryo becomes endowed with a constitution that is more stable and more vig- orous than that of the embryo developing from an egg in which the initial amount of chromatin is less. Such an hypothesis is, of course, only tentative. Until our knowledge of heredity and of the sex-determining mechanism is greatly increased it will be futile to theorize as to the probable cause for particular characters associated with one sex or the other which seemingly do not depend upon the action of specifie genes. The great excess of males among aborted and stillborn fetuses is readily explained if we assume that, from the time of concep- tion, the embryo that is to develop into a male has a constitution inherently weaker than that of the embryo that is to become a female. During the gestation period many factors, such as dis- ease, unfavorable environmental conditions, physiological changes incident to age, etc., may lessen the mother’s power of assimilat- ing food and of transmitting it to her fetal young. Under these conditions, a male fetus possessing a relatively low initial vitality would be more severely handicapped by inadequate nutrition or by conditions unfavorable to normal development than would a female fetus having a greater initial vigor of constitution and more power to resist unfavorable environmental conditions. One, therefore, would expect to find the facts exactly as shown by various series of investigations cited in this paper, namely, that at all stages of gestation and at birth the mortality among the males is far greater than that among the females. SUMMARY 1. Birth statistics collected during a period of five years show that in a total of 31,670 newborn albino rats 415, or 1.3 per cent, were stillborn. Allowing for the probable error in recording the 350 HELEN DEAN KING data, it would appear that under normal environmental conditions not more than 2 per cent of rat fetuses are dead at birth. The most accurate statistics available indicate that the normal birth mortality in man is about 4 per cent. There are no data of value regarding the percentage of stillbirths in other mammals. 2. The normal sex ratio in newborn albino rats, including the stillborn, is about 107 males to 100 females; in man the sex ratio for the living young at birth averages about 105.5 males to 100 females, and if the stillborn are added the sex ratio rises to about 108 males to 100 females. 3. In each year that the mortality records for newborn rats were taken there was a pronounced excess of males among the stillborn, the sex ratio in the total number of such individuals being 129.3 males to 100 females (table 1). Large series of birth statistics collected in many different coun- tries show that the sex ratio among stillborn children is very high, averaging about 130 to 140 boys to 100 girls. The excess of boys becomes greater the earlier the month of pregnancy in which the fetus dies. 4. In the rat the percentage of stillbirths seems to vary some- what with the seasons, being least in the spring and greatest in the autumn months when the breeding animals are suffering from the devitalizing effects of high temperature during the preceding summer (table 4). The birth mortality among human offspring does not, apparently, vary to any appreciable extent at different periods of the year. 5. Data collected during one year show that the mortality among young rats during the first three days after birth was 2.3 per cent, or slightly greater than the birth mortality in the col- ony during the same period (2.16 per cent); infant mortality in man during the first month after birth is about 5 per cent, or 1 per cent higher than the birth mortality. Postnatal mortality in the rat is largely due to accidental causes which tend to kill more females than males; in man the death of many infants is traceable to prenatal causes which seem- ingly are more fatal to boys than to girls. BIRTH MORTALITY IN THE RAT AND IN MAN 351 6. Factors responsible for a considerable proportion of the stillbirths among human offspring, such as, infectious disease, faulty implantation, mechanical obstructions to birth, including the size of the fetus, apparently play no part, ordinarily, in the birth mortality of the rat. 7. From the data obtained it appears that malnutrition is directly responsible for most of the stillbirths in the rat. Fac- tors influencing the food supply of the fetal young, such as the physical condition and the age of the mother, the suckling of young, and the size of the litter carried, are therefore the chief causes of birth mortality in the rat. 8. Available evidence indicates that both in the rat and in man the male fetus is intrinsically weaker than the female, and therefore more susceptible to prenatal influences inimical to normal development. A tentative hypothesis is advanced that the difference in the constitutional vigor of the sexes has its basis in the different chromatin structure of the male and female zygote. THE ANATOMICAL RECORD, VOL, 20, NO. 4 352 HELEN DEAN KING LITERATURE CITED ALLEN, E. 1918 Studies in cell division in the albino rat (Mus norvegicus, var. alb.). ILI. Spermatogenesis: the origin of the first spermatocytes and the organization of the chromosomes, including the accessory. Jour. Morph., vol. 31. ALLEN, N. F. 1919 Infant mortality. Results of a field study in Saginaw, Mich., based on births in one year. Children’s Bureau, U. 8. Dep’t of Labor, Wash ngton. Asupy, H. T. 1915 Infant mortality. Cambridge. AversacH, ©. 1912 Das wahre Geschlechtsverhiltnis des Menschen. Arch. Rassen- u. Geschlechaftsbiol., Bd. 9. Bernoutu, C. 1841 Handbuches der Populationistik. Broruers, A. 1896 Infantile mortality during child-birth and its prevention. Philadelphia. CarvaLito, M. E. 1912 La masculinité dans les naissances humaines. Compte Rendu Assoc. Franc. pour d’Avancement des Sciences, T. 41. Cuénort, L. 1899 Sur la determination du sexe chez les animaux. Bull. Sci. de la France et de la Belgique, T. 32. Davis, W. H. 1918 Birth statistics for the birth registration area of the United States, 1916. Bureau of Census, Washington. 1919 Birth statistics for the birth registration area of the United States, 1917. Bureau of Census, Washington. 1920 Birth statistics for the birth registration area of the United States, 1918. Bureau of Census, Washington. Dempsey, M. V. 1919. infant mortality. Results of a field study in Brockton, Mass., based on births in one year. Children’s Bureau, Dep’t of Labor, Washington. Donatpson, H. H. 1906 A comparison of the white rat and man in respect to the growth of the entire body. Boas Anniversary Volume, New York. 1908 A comparison of the albino rat with man in respect to the growth of the brain and of the spinal cord. Jour. Comp. Neur., vol. 18. 1915 The rat: reference tables and data. Mem. Wistar Institute Anat. and Biology, no. 6. 1918 A comparison of the growth changes in the nervous system of the rat with corresponding changes in the nervous system of man. Proc. Nat. Acad. Sciences, vol. 4. ¢ Duke, E. 1915 Infant mortality. Results of a field study in Johnstown, Pa., based on births in one year. Children’s Bureau, U. 8. Dep’t of Labor, Washington. Duncan, B.S., AND Duke, E. 1917 Infant mortality. Results of a field study in Manchester, N. H., based on births in one year. Children’s Bureau, U.S. Dep’t of Labor, Washington. ; Disine, C. 1884 Die Regulierung des Geschlechtsverhiltnisses bei Vermehr- ung der Menschen, Thieren und Pflanzen. Jen. Zeitschr. Naturwiss., Bd. 17. BIRTH MORTALITY IN THE RAT AND IN MAN 353 Durron, A. S. 1910 The greater frequency of stillbirths and deaths under one year among males than females. Med. Press and Circular, vol. 89. Eastman, P.R. 1919 The relation of parental nativity to the infant mortality of New York State. Amer. Jour. Diseases of Children, vol. 17. Geppes, P., anp Tuomson, J. A. 1901 The evolution of sex. Revised edition, London. GoreuLert, V. 1882 Ueber die Vererbung der Haarfarben bei den Pferden. Zeitschr. Ethnologie, Bd. 14. Guyer, M. F. 1910 Accessory chromosomes in man. Biol. Bull., vol. 19. Hammonp, J. 1914 Some factors controlling fertility in domestic animals. Jour. Agr. Sciences, vol. 6. Heare, W. 1909 The proportion of the sexes produced by white and coloured peoples in Cuba. Phil. Trans. Royal Soc., London, vol. 200. Hirscu, M. 1913 Ueber das Verhiiltnis der Geschlechter. Centralbl. fir Gyn- aikologie, Bd. 37. Horrmann, L. 1885 Mitteilung ueber Abortus. Deutsche Zeitschr. fir Tier- medizin, Bd. 11. Huser, G. 1915 The development of the albino rat, Mus norvegicus albinus. II. Abnormal ova: end of the first to the end of the ninth day. Jour. Morph., vol. 26. Hunter, E. B. 1918 Infant mortality. Results of a field study in Waterbury, Conn., based on births in one year. Children’s Bureau, U. 8. Dep't of Labor, Washington. Jackson, C.M. 1913 Postnatal growth and variability of the body and of the various organs in the albino rat. Am. Jour. Anat., vol. 15. JeNDRASSIK, E. 1911 Ueber die Frage des Knabengeburten-Ueberschusses und ueber andere Heredititsprobleme. Deutsche mediz. Wochenschr., Bd. 37. Kine, Heten Dean 1913 Some anomalies in the gestation of the albino rat (Mus norvegicus albinus). Biol. Bull., vol. 24. 1915 On the weight of the albino rat at birth and the factors that ‘ influence it. Anat. Ree., vol. 9. 1916 On the postnatal growth of the body and of the central nervous system in albino rats that are undersized at birth. Anat. Rec., vol. 11. 1916 a The relation of age to fertility in the rat. Anat. Rec., vol. 11. 1918 Studies on inbreeding. I. The effects of inbreeding on the growth and variability in the body weight of the albino rat. Jour. Exp. Zool., vol. 26. 1918 a Studies on inbreeding. III. The effects of inbreeding, with selection, on the sex ration of the albio rat. Jour. Exp. Zool., vol. 27. Kine, Heten Dean, anv SrotsensuRG, J. M. 1915 On the normal sex ratio and the size of the litter in the albino rat. Anat. Rec., vol. 9. Kirkuam, W. B. 1916 The prolonged gestation period in suckling mice. Anat. Rec., vol. 11. Kroon, J.P. 1917 lets over de verhouding der sterfte van mannen en vrouwen. Nederlandsch. Tijdschr. voor Geneskunde, B. 61. Lewis, C. J., aNp Lewis, J. N. 1906 Natality and fecundity. New York. 354 HELEN DEAN KING Linu, F. R. 1917 The free-martin; a study of the action of sex hormones in the foetal life of cattle. Jour. Exp. Zool., vol. 23. Matt, F. P. 1908 A study of the causes underlying the origin of human mon- sters. Jour. Morph., vol. 19. Morean, T. H. 1919 The physical basis of heredity. New York. Nicuots, J. B. 1907 The numerical proportions of the sexes at birth. Mem. Amer. Anthropological Assoc., vol. 1. Prnarp, A., eT MaGnan, A. 1913 Sur la fragilité du sexe male. Comptes Rendus, T. 156. : Pixs, F. H. 1907 A critical and statistical study of the determination of sex particularly in human offspring. Amer. Naturalist, vol. 41. Prinzine, F. 1906 Handbuch der medizinischen Statistik. Jena. Ravper, A, 1900 Der Ueberschuss an Knabengeburten und seine biologische Bedeutung. Leipzig. Scuutrz, A. H. 1918 Studies in the sex-ratio in man. Biol. Bull., vol. 34. Stonaxker, J. R. 1912 The effects of a strictly vegetable diet on the sponta- neous activity, the rate of growth, and the longevity of the albino rat. Pub. Leland Stanford Jr. Univ. Sozinskpy, T. 1885 Statistics and other features of still-births. Med. and Surgical Reporter, vol. 52. Srant, H., unp Hennesurea, B. 1902 Ueber Riickbildungserscheinungen am graviden Siiugetieruterus. Anat. Anz., Bd. 20. Terry, S. H. 1917 The secret.of sex. New York. Watpvocer, A. M. 1913 Statistische Bemerkungen zu den Geburten in der Kgl. Universititsklinik in Miinchen in dem Zeitraum von 1892-1912. Inaug. Dissertation, Miinchen. Wuirrte, G. C. 1919 Vital statistics. New York. Wickens, M. 1886 Untersuchung ueber das Geschlechtsverhiiltniss und die Ursachen der Geschlechtsbildung bei Haustieren. Biol. Centralbl., Bd. 6. Von Wriniwarrer, H. 1912 Etudes sur la spermatogenése humaine. II. Hétérochromosome et mitoses de I’épithélium séminal. Arch. de Biol., Pate i se ae - i an iwetee = ia q ‘ , Th eel i invent yah Qoet Fi eres ee eh moti Pe hei neiaehl iy f tn lee ML ys, y Kha? 4 jim a} aoe t 4] My @tsy ye PN Otte al "end. 1 )-te5 1} tPA. T ee j ft To ea Late tera allt ear ia ee ey ee halite egies >! } ine ehPucd ric noe OAL, 1, wt pint A} iF wou U . Lap Baa : av Net pee eas trie. if: OT: ners : dette: ards aoe be i ta eee oe ma Ss Gay _. 0 a ee » 7 4 =. oh prt ea re Ue el aay “ae an ; a’, > ss, pe eh Tie ae Seb Kita | 29 ye Tiel od Vache We . Resumen por el autor, David M. Siperstein. Universidad de Minnesota. Los efectos de la inanicién aguda y erénica sobre el desarrollo y la estructura del testfeulo de la rata albina. FE] desarrollo postnatal normal del testiculo ha sido estudiado por el autor en una serie de ratas albinas. Estos testfculos fueron comparados con los de ratas sometidas a una alimentacién deficiente durante varios periodos. Unas cudntas ratas fueron alimentadas con una dieta abundante después de una inanicién: prolongada. Los resultados mds importantes de estos estudios son los siguientes: I. En ratas de dos dias el testiculo aumenta en peso a pesar de haber sometido al animal al hambre durante 48 a 50 horas, pero las mitosis disminuyen en nimero y el proceso normal de la diferenciacién histol6gica cesa. 2. Durante el periodo de nutricién deficiente durante tiempo variable en ratas de tres semanas, la mitosis contintia en las células de los tubos seminfferos, pero el proceso de la espermatogénesis cesa en el estado de espermatocito primario. Los espermatocitos degen- eran y son reabsorbidos. Las espermatogonias y células de Sertoli solamente presentan cambios degenerativos en los casos de inanicién extrema. 3. La inanicién aguda en las ratas adultas con pérdida del 30 a 47 por ciento del peso total produce cambios degenerativos en unos cudntos ttibulos esparcidos irregularmente. Todos los demas ttibulos presentan una estruc- tura normal en apariencia. 4. La mitosis es’ muy persistente en el epitelio seminffero y tiene lugar atin en aquellos ttibulos en los cuales casi todas las células aparecen mds 0 menos degen- eradas. 5. La alimentacién abundante después de una inanicién prolongada (comenzada a las tres semanas de edad y extendida sobre 12 a 20 semanas) da como resultado la vuelta rdpida a la estructura histolégica normal. 6. Durante el periodo regen- erativo el autor ha comprobado la existencia de una hipertrofia definida del tejido intersticial e hiperplasia de las células intersticiales. Translation by José F. Nonidez Cornell Medical College. New York AUTHOR'S ABSTRACT OF THIS PAPER I88UED BY THE BIBLIOGRAPHIC SERVICE, FEBRUARY 7 THE EFFECTS OF ACUTE AND CHRONIC INANITION UPON THE DEVELOPMENT AND STRUCTURE OF THE TESTIS IN THE ALBINO RAT DAVID M. SIPERSTEIN Institute of Anatomy, University of Minnesota, Minneapolis FOURTEEN FIGURES CONTENTS MEELOLIRMONLOMOUNOUS Wate Saeco ewer eee <= 2... s sewalaectenien 356 |) OUST COUR a Aa Roe ge gee ae th 2S 2 re ae 357 1. Normal postnatal histogenesis of the testis............................ 357 2. Changes in young rats subjected to acute inanition................... 362 3. Changes in rats held at maintenance by underfeeding from three to ten WOEDR GLARE amen sent e eee SL ls fb 364 4. Changes in young rats retarded by underfeeding for long periods begin- ING Gh BORGO wer kre OAM Or eee las oe cnig a cvjccaneeaceessciecs 367 5. Changes in adult rats after acute inanition............................ 369 6. Changes in rats refed after underfeeding beginning at three weeks of age and extending for various periods............... 2... 00.0.0 cccceecee 372 DRC BEEN Roe et oe ea tee ee EE er os oS cae walla ws cules nie 375 1. Origin and significance of polynucleated giant cells.................... 375 Sa WIICOMe CULM ene eee yee ee sok 375 3. Interstitial tissue during inanition............... 2.00... c cece cee eeeee 376 SRT hae on SLM rr 377 EOD NORFOD DY sits ee see a eeee EEE a eet 379 The immediate and the remote effects of inanition upon the young organism are subjects of interest and importance, especially at the present time. Experimental studies in this field have yielded much of importance to biology in general and to medicine in particular. It is very desirable to know more about the changes produced in the sex glands of malnourished or under- nourished infants and children, and the resulting effects upon the reproductive system in later adult life. Inanition in adults may also occur either alone or associated with acute or especially with chronic wasting diseases, causing degenerative processes 355 356 DAVID M. SIPERSTEIN in the sex glands. Recent work on vitamine deficiencies (by MeCarrison, Allen, Dutcher, and others) indicates that the changes produced in the sex glands by this partial inanition resemble those found after general inanition. A study of the changes occurring in the histological structure of the testis of the albino rat during experimental inanition at various ages was therefore undertaken, and the results are embodied in the present paper. MATERIAL AND METHODS A large part of the material for this investigation was presented to me by Dr. C. M. Jackson, to whom the writer is also very much indebted for constant advice, aid, and criticism throughout the course of this study. The material comprises the testes of several - albino rats (Mus norvegicus albinus) that had been subjected to inanition experiments in the Institute of Anatomy. The adult animals during acute inanition were allowed water only; but one of the adults was placed on total inanition, as were also the young rats (two days old) which were removed from the mother and given neither food nor water. Those on chronic inanition were fed restricted amounts of Graham bread soaked in whole milk for various periods. Some were refed fully after underfeeding for various periods. The animals were killed by chloroform and autopsied, the testes being weighed (without epididymis) and portions fixed for histological study. For con- venience the material at my disposal is grouped as shown in table 1. In the first column, representing the individual rat numbers, the letters indicate the series (those autopsied by myself are ‘Si’), the number following indicates the litter, while the number after the decimal point identifies the individual rat. The testes had been fixed in either Zenker’s, Bouin’s, or Flemming’s fixatives. Paraffin sections were cut at 2 to 104 in thickness. The sections were stained chiefly with haema- toxylin and eosin, Weigert’s iron haematoxylin counterstained with Van Gieson’s stain, or Heidenhain’s iron-alum haema- toxylin counterstained in some instances with orange G or acid EFFECTS OF INANITION UPON TESTIS—-ALBINO RAT 357 fuchsin. In general, Heidenhain’s iron-alum haematoxylin with- out any counterstain gave by far the best results. My own material was fixed in Carnoy’s mixture (no. 1) and in Bouin’s fluid. Fixation for one hour with Carnoy’s mixture was found to be best. Sections were stained with Heidenhain’s iron-alum haematoxylin with or without counterstain (acid fuchsin). This gave clear-cut karyokinetic figures in all stages of mitosis. A number of measurements of cross-sections of tubules were also taken from the stained sections by means of a micrometer eyepiece. Sections of each testis containing the largest number of tubules cut in cross-section were chosen. In each section all the tubules showing a true cross-section (approximately circular) were measured. The results embodied in table 1 are therefore the average of measurements of a variable number of tubules, ranging from 8 to 44 in the individual cases. While the observa- tions are relatively few in number, they are sufficient to indicate clearly any marked change in size. In addition, a few (ten to fifteen) nuclei of the interstitial cells in both the control and the test rats were measured at various stages and the averages calculated. Only a sufficient number of testes was taken from each group to determine whether any marked change in the size of the nuclei had taken place as a result of the test conditions. The results are listed in table 1. No measurements of the cell body were attempted, on account of the irregularity of form. Measurements on the seminiferous epithelial cells were likewise found to be impracticable. OBSERVATIONS 1. Normal postnatal histogenesis (group 1) In order to understand more fully the changes which inanition produces in the testis, it is essential to review briefly its normal histological structure and histogenesis as a basis for comparison. Newborn (fig. 1). In microscopic sections of ‘the testis in the newborn rat, the seminiferous tubules appear closely packed together at the periphery of the testis, while in the center of the SIPERSTEIN DAVID M. 358 OL L OF 6010 (%Sz s80}) O1'F “SIq OG PdAreyg 9% $68 Tet0 Tg00°0 (%1Z 880]) 12°F “BIT Of pearsyg £6 Is 6 FE ZOO €h00°0 (%G@ 8801) 10°F “SI 8p peareyg TT Ig YMiq 10438 SABp OM} BuIjIe4S SyR1 UL UOTyIURUT eyNoOW—T] nosy oP 1&8 Z18°0 SPSL*S O'FIE sAep OGF : OFT S 8296 £261 0869°% 0°0F1 SAep OL es 1s oF SHG OZL T 0€00°T €°8¢ sAep 69 TIrts Sey, L°SL1 GIL 1 O9FS 0 @ SP skup 9¢ TOT 's P Gee O°LL skep 9¢ og 48 0° SEs 880°T OFG6E'O o 98 SABp Ef TL IS £°01Z SPl°0 S680 L°8& skep ce Tart is 188 ebro SILO 0°9% sdup 08 vs LY £66 OPPO 0260 °0 9°02 SAEP 1G 09 IS 's9 629°0 0820°0 L¥1 sABp FT 21 18 69 ¢'0¢ 6120 00z0°0 16 sXep 2 e1 is er 99°0 c00'0 OL skep F a1 Is UL Ll Gr ¢80°0 1900°0 TL skup F s32 IS | a GLE 220°0 6Z00°0 Teg MIOQ&2N yT Ig Dsus psnut 799 sod suni0 suns s[o1juos jeuLIoN—y] dnowy sient TVILLLSUALN SaTafas Co aweerric nO taRA Pere cecaeen LHOIGM AGO TVNIA ‘Ola ‘SOV USaWON LIVE SOVUGAY fipnjs poo opojsty 40f pasn sos ourgyp 94] Ur 89789) 947 fo 7ybiam pun jyBram fipog sso1B ‘uoyrpuos pun abo ‘saqunu jonpuaipuy 1 W1Tav 359 EFFECTS OF INANITION UPON TESTIS—-ALBINO RAT “162 PLT ZSIG'S 0° 61% . 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SIPERSTEIN , section the tubules are less compactly arranged. The tubules average 37.24 in diameter. The intertubular spaces contain many small capillary vessels and mesenchymal cells. The tubules themselves consist chiefly of a single layer of parietal epithelial cells, which apparently correspond to those designated as ‘Sertoli cells’ by v. Ebner (’02) in the testis of the colt. These cells fuse to form a syncytium. Lumina have not yet appeared in the tubules. The central portion of each tubule contains from one to three large clear cells, each containing a definite, well- marked nucleus. Each nucleus has from one to three small clumps of chromatin situated usually (but not always) close to the periphery of the nucleus. These masses probably represent chromatin nucleoli. These large central cells apparently corre- spond to those described by v. Ebner (’02, fig. 1147) as the primi- tive germ cells (‘Ursamenzellen’) from which the spermatogonia are probably derived. Interstitial cells (of typical structure) have not yet developed. There is present, however, in the intertubular tissue a peculiar type of cell which appears to be the forerunner of the later inter- stitial cells (fig. 14, A). This cell contains a large round nucleus (average diameter, 7.14) extremely rich in chromatin, which in turn is surrounded by a narrow rim of clear cytoplasm. By the form of its nucleus and its deeply staining chromatin, it is easily distinguished from the ordinary young mesenchymal or connective-tissue cell. Fourth day (fig. 2). In a normal rat at four days of age the development of the testis has advanced considerably. The whole section is filled with seminiferous tubules (average diam- eter, 41.74). Within the tubules themselves the parietal cells show no material increase in number, but the spermatogonia (Allen’s cell type A) have appeared. They are probably derived from the central cells (‘Ursamenzellen’ of v. Ebner), which still occur (less numerously) and present mitoses, though less fre- quently than in the newborn. Before dividing, they often appear to migrate from the center of the tubule toward its périphery and crowd in among the parietal cells. Some tubules already contain a few cells which resemble Allen’s type B; that is, a EFFECTS OF INANITION UPON TESTIS—-ALBINO RAT 361 primary spermatocyte cell in its earliest phase. The forerunners of the interstitial cells are beginning to group themselves together in the intertubular spaces. One week (fig. 3). A section of the testis from an albino rat at seven days shows an increase in the number and size of the tubules (average diameter, 50.54). (The larger number of tubules appearing in a cross-section of the testis may, however, be due to an increase in the length of the tubules rather than an actual increase in their number.) This represents the earliest stage described by Allen (’18). The tubules now contain two or three layers of cells. Very few central cells still remain, but spermatogonia (Allen’s type A) are present in large numbers. There are very few type B cells. In other words, an undiffer- entiated condition of the spermatic epithelium still prevails. The syncytium (Sertoli syncytium) which fills the tubules at this stage is exceptionally well shown. The number of mitotic figures has again increased, so there are now as many figures in the field as there were at birth. The interstitial cells are more numerous and the amount of interstitial tissue is increased. Two weeks (fig. 4). There is a large increase in the apparent number of seminiferous tubules, and their average diameter has increased to 65.34. There are many cells of types A and B, and some tubules even show Allen’s type C (spermatocytes in which the chromatin masses become more diffuse than in type B and assume a ‘woolly appearance’). A few cells have advanced as far as the leptotene stage. It is now fairly easy to distinguish between Sertoli cells and spermatogonia. The Sertoli cell has a nucleus with only a little chromatin material, in this way differing from the nucleus of the spermatogonium, which has a large amount of deeply staining chromatin. Three weeks (fig. 5). Lumina are just beginning to appear in the closely packed tubules, whose average diameter has now increased to 99.74. Spermatogonia, cells of types A, B, and C, are numerous. A few tubules already contain primary spermato- cytes showing mitotic figures. In many places, degenerating primary spermatocytes and spermatogonia are also present. This appears to be a normal physiological process, occurring in 362 DAVID M. SIPERSTEIN the testis at all ages. No secondary spermatocytes or spermatids are to be seen. The interstitial tissue is assuming its adult structure (fig. 14, B). The nuclei average only 4.7u in diameter, which is much smaller than at birth (7.1). One month (fig. 6). The testis at this stage shows only a slight advance in development. It is distinguished by the large number of primary spermatocytes present. Spermatids have not yet appeared. ‘The interstitial tissue shows no change. Six to ten weeks. Sections of testes from forty-three to seventy days of age show a gradual increase in the size of the tubules (table 1) and in the number of mature sperm elements. Mature spermatozoa appear for the first time at the age of forty-three days. Their number increases so rapidly that at eight weeks (fig. 7) the histological structure of the testis differs in no impor- tant respect from that in the older rats. The interstitial cells show no noticeable change in structure. Judging from the statements of Hewer (’14) and Allen (’18), there appears to be considerable variation in the age at which the various steps in the process of spermatogenesis occur in the albino rat. Hewer reported that there is no differentiation of primary spermatocytes from spermatogonia until the twenty- fifth day after birth. Allen found that his rats reached the pachytene stage at two weeks; while my material first shows this stage at three weeks. Hewer found that lumina first appear in the tubules at seven weeks. Allen demonstrated them in all rats fourteen days old. In my own rats fourteen days old I found no evidence of definite lumina, but they begin to appear at twenty-one days. Hewer stated that spermatozoa are not present in the lumina of the tubules until nine weeks after birth. Allen found spermatozoa in rats at the age of thirty-seven days, which corresponds closely with my observation at forty-three days. ' 2. Changes in young rats subjected to acute inanition (Group IT) A comparison of the testes of the normal control (at four days) with those of the test animals of same age (but lesser body weight) in table 1 shows but little apparent retardation in the growth EFFECTS OF INANITION UPON TESTIS—ALBINO RAT 363 in weight of the gonads of the latter (average weight in two con- trols, 0.0053 gram; in three test rats, 0.0046 gram). Although the test rats were kept on total inanition for forty-eight to fifty hours, the testes have evidently maintained nearly normal growth, although the body weight has decreased 21 to 25 per cent. The remarkably persistent growth of the testes in the starved rats is especially evident upon comparison with the newborn of the same litter (Si 1.4). The starved rats have decreased in body weight until they, although four days old, are about 20 per cent below the normal newborn. The testes, however, show a large increase in weight (in spite of the total inanition). The change in weight from 0.0029 to an average of 0.0046 grams represents an increase of 59 per cent. This is in general agree- ment with the results of Stewart (’I8), who found that in rats kept at maintenance (constant body weight) by underfeeding from birth to (average) sixteen days the testis apparently increased about 374 per cent in weight. The smaller increase in the testes of my starved rats is probably due to the greater severity and shorter duration of the inanition. My measurements indicate that this increase of 59 per cent in the weight of the testes is due almost entirely to the increased number of tubules seen in a section. The size of the tubules has remained about the same. There has perhaps been some retardation of the normal growth in size of the tubules. The normal testis at four days shows an average tubular diameter of 41.74, while the average diameter of the tubules in group II is only 38.4u. This small difference, however, is of doubtful significance. All three of the starved young rats (Si 1.1, Si 2.3, Si 2.6) show practically the same histological structure in the testis. The tubules are close together and more numerous than in the new- born, although there are relatively few in the center of the section. Cell differentiation has not progressed much beyond that found in the newborn. Each tubule presents the single layer of parietal cells. These cells are all alike and contain large nuclei, with very little chromatin material, surrounded by a 364 DAVID M. SIPERSTEIN narrow strip of clear cytoplasm. The central cells (‘Ursamen- zellen’ of v. Ebner) like those already described in the normal testis are also still present. There are very few mitotic figures either among the parietal cells or the central cells (fig. 8). See- tions (stained with iron-alum haematoxylin) of the testes of controls show many mitotie figures in each field (figs. 1 and 2). This decrease in the number of karyokinetie figures is probably due to the condition of inanition. In general, the histological picture shows that the testis has advanced to the stage when type A cells are beginning to appear. Thus the stage of differ- entiation is somewhat beyond that corresponding to the normal at similar body weight, but behind that corresponding to the age or actual testis weight. The increase in the (apparent) number of tubules evidently accounts for the increase in the size (weight) of the testis. Swingle (’18) similarly found that total starvation inhibits the growth and metamorphosis of Rana pipiens larvae. Sper- matogenesis ceases and sex differentiation is prevented. 3. Changes in rats held at maintenance by underfeeding from three to ten weeks of age (group ITT) In the five rats of this group held nearly at constant body weight by underfeeding from three to about ten weeks of age, the testes, though below normal weight for that age, have been retarded in their growth far less than has the body weight. . Thus on comparing the average data for group III (table 1) with the normal control at three weeks (Si 6.0) it appears that the body weight has increased from 20.6 grams to 26.9 grams, an increase | of about 31 per cent; while the testes have increased from 0.0920 gram to an average of 0.1955 gram, an increase of about 113 per cent. This would indicate a relative growth for the testis even greater than that (+34 per cent) found by Jackson (’15 a) under similar conditions. Individual variations in the control or test rats probably account for the difference. The size of the tubules in group III has apparently increased from an average diameter of 99.74 (normal at three weeks of EFFECTS OF INANITION UPON TESTIS—-ALBINO RAT 365 age) to an average diameter of 110u. This increase in diameter (though of doubtful significance) would indicate that the increase in the weight of the testes is due in part to the increase in the diameter of the tubules. With the exception of one rat (S 11.65), which will be men- tioned later, the testes in this group all present the same micro- scopic picture (fig. 9). The tubules are placed close together. Lumina are just beginning to appear, although most of the tubules still show no central lumen. No spermatozoa or sperma- tids are present. There is no evidence to indicate that they had ever been developed and had undergone necrosis. A few second- ary spermatocytes can be seen, but they are abnormal in structure. Almost every primary spermatocyte also shows some degenera- tive changes. The cytoplasm becomes coarsely granular and contains clumps of basophilic staining material. Other cells show a fatty (?) degeneration or vacuolization of the cytoplasm (a positive statement cannot be made, as material stained for fat was not available). The nuclei degenerating by a process of karyorrhexis may give rise to the basophilic granules present in the cytoplasm of so many spermatocytes. The pyenotic nuclei are very abundant and, with progressive necrobiosis, appear gradually to lose their staining capacity, terminating in karyo- lysis. The cytoplasm also progressively loses its staining capacity and gradually disappears. The spermatogonia, however, appear nearly normal. The Sertoli cells are increased in number, but show no structural changes. The tubules are filled with a structure resembling the ‘degeneration reticulum’ described by Kuntz (20) in the testis after division of the nerves. This appears to me to be due largely to the Sertoli syneytium which becomes visible in direct ratio to the number of other cells which are being destroyed. Allen (19) pointed out that in normal tubules the Sertoli syncytium is hard to see on account of the closely packed germ cells. As a result of experimental conditions, the syncytium is made more prominent by the removal of the germ cells which normally obscure it. THE ANATOMICAL RECORD, VOL. 20, NO. 4 366 DAVID M. SIPERSTEIN There are present in all cases many multinucleated or giant- cells. These cells are situated in the center of the lumen, and each tubule usually presents one or two of them. Each cell may contain from two to four nuclei, all showing some degenerative changes. Multinucleated cells appear to be very characteristic of the degenerative process in the testis. To a certain extent, the degree of severity of the starvation can be measured by the size of these cells and the number of nuclei they contain. For example, absolute inanition for nine days (in the adult) produces giant-cells containing as high as twelve to fifteen nuclei, while in the slower chronic inanition in the present group, the number is reduced to three or four nuclei. One other important fact, which is strikingly illustrated in these sections, is the remarkable persistence of mitotic figures in the spermatogonia and primary spermatocytes. In rats which have been kept at constant body weight by underfeeding for seven weeks, the number and structure of the mitotic figures is apparently normal as compared with control rats (from three to four weeks). This fact is in agreement with the observations by many investigators (mentioned later) who have reported the presence of mitotic figures after prolonged chronic inanition. This mitosis is doubtless correlated with the persistent growth of the testis in the underfed young rats under these conditions, the new cells formed being in excess of those destroyed by degener- ation. My study of this group of albino rats kept at maintenance by underfeeding from three to ten weeks leads to the following conclusions: First, the chronic inanition prevents the testis from reaching the stage of spermatogenesis normal for the correspond- ing age. Second, in spite of the persistent mitosis and increased’ size of the testis, the process of spermatogenesis remains at the stage where spermatocytes are produced, corresponding to the normal stage at the age of three or four weeks. The growth capacity of the testis under these conditions of subnormal nutri- tion is apparently sufficient only to produce primary spermato- cytes from the spermatogonia. Third, the spermatocytes degen- erate and are absorbed, though not so rapidly as they are formed. EFFECTS OF INANITION UPON TESTIS—ALBINO RAT 367 The excess of production over destruction partly accounts for the continued growth in weight of the testis. Fourth, the inter- stitial tissue is apparently unchanged and resembles in quantity and structure the tissue present in a normal rat at the age of three or four weeks. In one rat (S 11.65, fig. 10) in this group, the testis shows such remarkable changes that it seems advisable to describe it sepa- rately. This was the left testis (indicated by (L) in table 1), which was markedly atrophic, weighing only 0.0496 gram. All the tubules show degenerative processes. Many contain no cells whatever. The lumina are filled with the characteristic ‘degeneration reticulum,’ and some have large vacuoles in their centers. Pycnosis, karyorrhexis, and karyolysis are prevalent. A few of the seminiferous tubules in this case show a type of degeneration which differs entirely from any other thus far described. All the nuclei in every cell in the tubule gradually and almost uniformly lose their basophilic staining capacity and become acidophilic, taking the red counterstains. At the same time the cytoplasm of all the cells fuses together and becomes homogeneous in appearance. So that the entire cytoplasm in the tubules finally becomes one single mass, resembling very closely the homogeneous mass of necrotic tissue seen in an infarct. This mass apparently undergoes a process of autolysis, and vacuoles later replace the cytoplasmic substance. This process continues until finally the structure disintegrates and the position of the tubule is indicated by only the membrana propria. In spite of this necrosis in the tubules, the intertubular tissue shows no marked degenerative changes. However, a very irregularly distributed moderate hyperplasia of the interstitial cells is appar- ent (fig. 14, D). While not the typical picture produced by the chronic inanition in group III, this condition evidently corre- sponds to the advanced degenerative process in an extreme case. 4. Changes in young rats retarded by underfeeding for long periods beginning at three weeks of age (group IV) In the three rats underfed from three weeks to 223 to 428 days of age (table 1) the body has approximately doubled in 368 DAVID M. SIPERSTEIN weight, whereas normally it should have increased to about twelve times the initial weight. The testes are likewise of course far below norm for the corresponding age, though apparently considerably above the norm for the younger rats of similar body weight (rats Si 10 and Si 11; also Donaldson’s Wistar norm). Stewart (’18), however, concluded that in rats underfed begin- ning at three weeks of age so as to reach only about 50 grams in body weight at 412 days of age the testes average 42 per cent below normal (for corresponding body weight). It is evident that the changes in the weight of the testis are extremely variable, so it is unsafe to draw general conclusions from only a few cases. Judging from the size of the tubules in normal testes of similar weight, the tubules in group IV should average above 200u in diameter. As shown in table 1, however, in three of the four eases the tubules appear subnormal (90 to 120u) in diameter. Microscopie sections (stained with haematoxylin and eosin) of the testis show that the size of the tubules in these rats long — underfed has considerably decreased. The number of tubules has also decreased and they have become widely separated (fig. 11), due in part to the accumulation of fluid in the interstitial spaces (edematous infiltration). No mature spermatozoa or spermatids appear, although they are present in normal rats of corresponding body or testis weight. Spermatogenesis here (as in group III) has apparently not passed the primary spermato- cyte stage. Most of the tubules contain three to four layers of cells, composed of spermatocytes and spermatogonia. The former show the most profound changes. Some appear as shadows without any nucleus or cytoplasm. Others have pycnotic nuclei and a homogeneous cytoplasm. Multinucleated giant-cells are present and the nuclei in these cells show pyenotie changes. Many spermatogonia and all the Sertoli cells appear normal. Mitotic figures are still present. Apparently some vascular changes have taken place. There is a slight sclerosis in the walls of the blood-vessels and also (apparently) a reduced blood-supply to the tubules. There is not any noticeable increase in the quantity of interstitial tissue (proper) (fig. 14, EZ) or any appreciable change in the structure of the interstitial cells, but the quantity of interstitial fluid has enormously increased. EFFECTS OF INANITION UPON TESTIS—ALBINO RAT 369 Since all three rats (St 44.1, St 44.4 and St 44.7) show the same histological structure, the question of individual variation may be excluded. So that it appears that the ‘growth tendency’ so strongly manifested in the testis during inanition in young animals is confined to the formation of the earlier cells in the spermatogenetic cycle; that is, the process can go only to the spermatocyte stage. This is probably what happened in the case of the rats in group III, as before mentioned. In one rat (M 29.109) inanition was started at ten weeks of age after the testis had presumably reached the stage when mature spermatozoa are produced. Even though kept at main- tenance (constant body weight) by extreme underfeeding for 244 days, this testis shows the following histological structure. Most of the tubules are normal in structure and size and show well-developed spermatozoa. However, many lumina are filled with a débris made up almost entirely of heads and tails of spermatozoa. A few tubules show a slight desquamation process, but this is not distributed evenly among the tubules and is probably of no importance. Aside from this, the structure of the testis is apparently normal. Mitotic figures are present and all the various stages of spermatogenesis can be followed out. The conditions in this case emphasize the importance of the age factor. It indicates that if the testis has reached sexual maturity before experimental inanition, the effect upon spermatogenesis is much less marked than in cases where the underfeeding is begun at an earlier period, although the further growth of the testis (in weight) may be hindered. No final conclusions can be drawn from this one rat, however, although the results are in agreement with the conclusions of Jackson and Stewart (’20) as to the importance of the age at which the inanition begins. 5. Changes in adult rats after acute inanition (group V) As shown in table 1 (group V), adult rats were subjected to acute inanition for periods varying from nine to twelve days. The loss in body weight varies from 30 to 47 per cent. The testes also apparently lose a great deal in weight, but the exact amount can of course be only roughly estimated. The test rats 370 DAVID M. SIPERSTEIN at the beginning of the experiment varied in body weight from 216 to 328 grams. According to the Wistar norm tables com- piled by Donaldson (15), these body weights call for from 2.5 to 2.8 grams of testis. A comparison with the figures in table 1 shows that at autopsy the testes in weight varied from 1.468 to 2.43 grams, indicating considerable loss in weight. The average diameter of the tubules has correspondingly decreased from over 300u to an average of 221.54. Jackson (’15) found that the loss in weight of the testis of adult rats during acute inanition is nearly proportional to that of the whole body. This agrees in general with the results obtained by Falck (’54), Voit (66), Manassein (’68), and Gerhartz (09). An atrophy of the testis relatively much greater than the decrease in body weight during inanition was noted in birds by Grandis (’89), and (during vitamine deficiency) by McCarrison (’19) and Dutcher (’20). A similar result in rats on lipoid-free diet was noted by Hatai (’15). In one rat (Si 9) which was held for eleven days without food or water, the testis had shrunken away from the tunica albuginea and had decreased considerably in size. This was, however, not apparent upon removing the organ at autopsy, because the inter- vening space was filled with a fluid, which kept the tunic dis- tended and gave it a normal rounded appearance. This phenom- enon has likewise been noted by Allen (’19) in his study of rats subjected to a diet deficient in the water-soluble vitamines. At first glance, the sections of the testes in this group appear perfectly normal in structure. The majority of the tubules are apparently normal in shape and show no signs of degeneration, as was likewise noted by Simonowitsch (’96). Spermatogenesis ‘appears to be going on as usual. Spermatozoa are abundant and show no alteration in structure. There is no apparent change in the amount or structure of the interstitial tissue. However, more careful study shows that in each section a few tubules have suffered as a result of the inanition. These tubules, though few in number and placed in immediate relation- ship with perfectly normal tubules, may show very marked and very severe changes (fig. 12). The spermatozoa are irregular in structure and show extreme degenerative processes. The sper- = EFFECTS OF INANITION UPON TESTIS—-ALBINO RAT 371 matids may present a picture which strongly suggests a true synizesis. This peculiar clumping of the chromatin toward the periphery and toward one side of the nucleus has been described by Monterosso (’12) as a form of degeneration. But I have observed this same structure in almost everyone of my control rats, and believe that we are dealing here rather with a rearrange- ment of the chromatin material in the normal cytomorphosis of the cell. The secondary and primary spermatocytes show marked necrobiotic changes. Even the spermatogonia are involved and reveal pycnotic and karyolytic changes in the nuclei. The Sertoli cells are apparently the only ones not severely injured. Depending on the stage of degeneration, large numbers of multinucleated giant-cells are present in the tubules. These cells each contain from four or five nuclei up to as many as twelve or fifteen nuclei. Some tubules are so atrophic and degenerated that only the membrana propria remains, with a few necrotic giant-cells in the lumina. These giant-cells were carefully studied with special reference to their origin. Appar- ently they are derived from primary spermatocytes, which fuse together in groups during their desquamation. These cells will be referred to again at a later period. Desquamation of the epithelial cells in these degenerating tubules is very common and apparently initiates the process of degeneration. This process appears to start with the secondary spermatocytes, but as the sloughing process continues the pri- mary spermatocytes and even the spermatogonia are detached into the degenerating mass in the lumen of the tubule. Degen- eration takes place in every case after desquamation has occurred. This degeneration apparently is also always in inverse order to that of spermatogenesis. The spermatozoa are the first to disappear, then the spermatids, followed by the spermatocytes and spermatogonia. The Sertoli cells are the most resistant. This agrees with the results obtained by Monterosso (in starved rats), Bouin and Garnier (in alecoholized rats), and Regaud and Tournade (after ligation of the spermatic cord). Allen (19) states that (in degeneration due to vitamine deficiency) “the 372 DAVID M. SIPERSTEIN spermatocytes seem to be the first affected, _ the spermatids next, and the spermatogonia last.’ It therefore appears that acute inanition notably affects but comparatively few tubules in the testis, and that the other tubules retain their normal structure, but all the tubules suffer a loss in size. In spite of a loss of about one-third in the weight of the testis, spermatogenesis apparently continues normally in most of the tubules. But the few tubules which for some unexplain- able reason are less resistant show atrophic and necrotic changes which are as marked as any found in chronic inanition. Likewise, atrophic and degenerative changes in the seminifer- ous epithelium during inanition have been described by Grandis (’89) in pigeons, Pernice and Scagliosi (’95) in chickens, Simono- witsch (’96) in rabbits and guinea-pigs, Loisel (’01) in the dog, Monterosso (’12) in rat and mouse, and Poiarkoff (713) in the dog. Similar changes have been described as a result of vitamine deficiency by McCarrison (’19) in pigeons and Allen (719) in rats. The extent of the degenerative changes naturally varies in general with the severity of the inanition. In the adult rabbit, Traina (’04) found that spermatogenesis ceases when the loss in body weight reaches about 30 per cent. There is also a variation according to species, season, ete. At certain periods the testis during inanition may even continue to develop at the expense of the remainder of the body in the salmon (Miescher, 97) and frog (Nussbaum, ’06). 6. Changes in rats refed after underfeeding beginning at three weeks of age and extending for various periods (group VI) In one rat (St 12.53) refed for three and one-half days (table 1), the refeeding period was too short to produce any. definite results. There is apparently already some increase in the total body weight, but very little, if any, in the testis. Sections show no definite change from the appearance of the testes in group IV. The primary spermatocytes still show necrotic changes and there is no advance in the stage of spermatogenesis. The EFFECTS OF INANITION UPON TESTIS—-ALBINO RAT 373 average diameter of the tubules (98.7) is slightly below that in rat 5 7.32, with similar testis weight. In another rat (St 10.26), refed for fourteen days after main- tenance by underfeeding from twenty-one to seventy-two days, many improvements have taken place. The body weight has increased from around 30 to 86.3 grams, but there is no great increase in the weight of the testes. The reason for this becomes more evident upon histological study. Sections (stained with iron haematoxylin) show no increase in the number and but slight increase in the diameter of the tubules, compared with those of group III. But all the débris has been removed and no degenerating cells are to be seen (fig. 13). No secondary sper- matocytes are present. The interstitial cells and their nuclei appear normal (but increased in size). They are, however, definitely increased in number above normal. They are evenly distributed throughout the testis, in this way differing from the condition found by Allen (’19) in the rats of Osborne and Mendel subjected to a diet deficient in the water-soluble vitamines. There are numerous mitotic figures among the spermatocytes and spermatogonia, showing all the stages of the karyokinetic cycle. The blood-vessels are distended with blood. It would appear that all the energy in the testis has been utilized to ‘clean up’ the waste material and to prepare for a further advance. This may account to some extent for the lack of increase in the weight of the testis. In the rat (S 12.52) which was refed for thirty-seven days, the weight of the testis has greatly increased and histological study shows that spermatogenesis is going on normally. The tubules are normal in structure and contain many mature sperma- tozoa. The average diameter of the tubules has, however, increased to 222.7u, accounting for the increase in weight. The only difference to be found (as compared with normal control testes) is an increase in the amount of interstitial tissue (fig. 14, F). We must distinguish between interstitial tissue and interstitial cells. The former term applies to all tissues outside of the tubules proper; the latter (interstitial cells) refers only to the 374 DAVID M. SIPERSTEIN specifie cells playing a part in the internal secretion of the testes. In reality, there is not so much a general hypertrophy of the interstitial tissue, but rather a hyperplasia of the interstitial cells proper. There is a marked increase in the number of these cells and a slight increase in their size. They assume a more or less cord-like arrangement. The nuclei of the cells are spherical and rather vesicular, although a few clumps of chromatin are always present close to the periphery. A light granular cyto- plasm surrounds the nuclei. After the very young stages (one to seven days), mitosis among these cells has never been observed. One possible explanation which may be offered is that mitosis in these cells takes place very rapidly, so that, although cell division occurs, it is rarely found in the sections. The fourth rat in this group (S 33.118), refed for 206 days, has completely recovered from the effects of the underfeeding and presents a perfectly normal adult histological structure. The diameter of the tubules shows an increase of 291.14. Even the interstitial tissue and cells appear normal in quantity and structure. These results are in accord with the work of Stewart (’15), who found that in rats refed after underfeeding from three to twelve weeks of age, the testes remain somewhat below normal weight for a few weeks, but regain normal weight before the adult stage is reached. In later experiments (Stewart, 718), in which the underfeeding was prolonged, the testis became markedly subnormal in weight (as found by Jackson, ’15 a). Jackson and Stewart ('19) reported that the testis, which increases in relative weight in young rats during underfeeding, remains somewhat above normal weight during refeeding to a body weight 25 to 50 grams, but is subnormal in those refed to 75 grams body. weight. Finally, Jackson and Stewart (’20) found that when the underfed rats are fully refed to maximum body weight, the testes are definitely above normal for the corresponding body weight. A restoration of the testis to normal structure and funetion upon refeeding after inanition has likewise been noted by Simonowitsch (’96) in rabbits and guinea-pigs, and by Loisel (01) and Poiarkoff (713) in dogs. EFFECTS OF INANITION UPON TESTIS—ALBINO RAT 375 DISCUSSION 1. Origin and significance of polynucleated giant cells It has been claimed by some authors that giant-cells may occur normally in the testis. I have never seen either a poly- nucleated or a giant-cell in a normal seminiferous tubule. Mon- terosso (712) found that these cells are very rare in normal tubules, but occur more frequently during early inanition. He found that their number increases with the length of inanition, and that as many as fifteen nuclei might be seen in a single cell. He believes that they are formed by a fusion of the neighboring cells. On the other hand, Bouin and Garnier ('00) believe that these cells are formed by an abnormal mitosis of the nuclei within the cell. Allen ('19) noticed these cells during the early stages of degeneration, but offered no explanation as to their origin. My studies lead me to believe that the multinucleated cell is formed by a fusion of primary spermatocyte cells when they begin to degenerate. Asa rule, these cells show marked nuclear and cytoplasmic degenerative changes later than those cells which break off independently and do not fuse with other cells. This suggests that fusion of cells may be a sort of protective measure from the effects of the inanition. De Bruyne (’99), however, claims that these polynuclear cells are precursors of degeneration. No mitotic figures have ever been observed in any polynucleated giant-cell. 2. Mitosis during inanition As to the occurrence of mitosis during inanition, my own obser- vations agree in general with those of Morpurgo (’88, ’89), Grandis (’89), Traina (’04), and others. Traina, for instance, found that mitotic figures persist after a loss in body weight of 30 to 35 per cent. On the other hand, Pernice and Seagliosi (95), in young chickens on water inanition, and Morgulis, Howe, and Hawk (’15), in fasting dogs, reported an absence of mitosis in the testis. In my adult rats subjected to acute inanition 376 DAVID M. SIPERSTEIN (S 25, S 26, S 27), with loss in body weight of 30, 35, and 39 per cent, mitotic figures are still present in large numbers. Another rat (Si 9), with loss in body weight of 47 per cent, still shows numerous mitotic figures. They are present even in tubules showing extreme degenerative changes. In young rats underfed from the age three to ten weeks, mitosis is apparently unaffected. Even in those animals in which the underfeeding was continued to 400 days or more, the mitotic figures can be seen in many of the tubules. It would therefore appear justifi- able to conclude that it is impossible by inanition to suppress mitosis entirely in the epithelium of the seminiferous tubule. The mitoses, however, may be decreased in number, as found in the rats two days old subjected to acute inanition. The presence or absence of amitosis in the testis has long been a disputed question. Monterosso (’12) found amitosis present among degenerating spermatocytes and spermatogonia. Allen (18, 719) believes that amitosis does not occur. I have likewise never seen a definite case of amitosis in any of my sections. 8. Interstitial tissue during inanition Some investigators mention the increased quantity of inter- stitial tissue, which is occasioned by any degeneration or atrophy of the seminiferous epithelium. Cordes (’98) found an increase in interstitial tissue in cases of chronic disease with cachexia. Kyrle (710) and Voss (’13) pointed out that in diseased conditions and in underdeveloped testes, the tubules are far apart and the interstitial tissue surpasses the tubules in amount. Allen (719) also found an increase in the quantity of interstitial tissue in rats fed upon a diet deficient in water-soluble vitamines. In my own series of albino rats, there appears in no case any demonstrable increase in interstitial tissue during either acute or chronic inanition. However, in those rats which were refed after various periods of underfeeding (group VI), there is a gradual increase in the relative amount of interstitial tissue (interstitial cells) until the gland regains its normal size and structure. Thereafter, the interstitial tissue apparently de- EFFECTS OF INANITION UPON TESTIS—-ALBINO RAT 377 creases in amount until it reaches the normal proportion. That is, the interstitial cells appear relatively increased in number only during the regenerative period. Measurements of the nuclei of interstitial cells indicate that there is a sharp decrease in the average diameter of the nucleus from 7.1 at birth to 4.74 at three weeks of age. From the three-weeks stage there is very little change in the size of the nucleus. Comparison with the test groups indicates that the size of the nucleus of the interstitial cells is not affected to any marked degree by the inanition tests. In group III, two of the three specimens measured show a decreased average diameter of the nucleus (in underfeeding from five to ten weeks of age); and in group VI, it would appear that refeeding causes some increase in the size of the nucleus, in addition to the numerical increase already noted. There is considerable individual vari- ation, however, and the number of observations is insufficient to warrant final conclusions. SUMMARY The results of the present investigation may be summarized as follows: 1. In the normal testis of the albino rat during the first post- natal week the (solid) seminiferous tubules consist of a single layer of parietal cells (‘Sertoli cells’ of v. Ebner) and a few central cells (‘Ursamenzellen’ of v. Ebner). After the first week, the normal postnatal development of the testis and the process of spermatogenesis proceed essentially as described by Allen (18). 2. In rats two days old starved for forty-eight to fifty hours, the testis increases markedly in weight, but mitoses are reduced in number and the normal process of histological differentiation is arrested. The seminiferous tubules remain nearly normal in diameter. 3. During underfeeding for various periods beginning in rats three weeks old, mitosis continues in the cells of the seminiferous tubules, but the process of spermatogenesis is arrested at the primary spermatocyte stage, which persists even in rats over 378 DAVID M. SIPERSTEIN 400 days old. The spermatocytes degenerate and are resorbed, but if the number formed exceeds those destroyed, the testis may increase in weight. Multinucleated giant-cells are formed during the process of degeneration. The spermatogonia and Sertoli cells usually persist unaffected, except in very extreme cases, where a complete degeneration and disintegration of the seminiferous epithelium may occur. If the underfeeding begins after sexual maturity, the seminiferous tissue is much more resistant and normal spermatogenesis may persist for a long time. The seminiferous tubules may increase slightly in diame- ter in the shorter tests, but usually appear subnormal in size in the longer experiments. 4. Acute inanition in adult rats, with 30 to 47 per cent loss in body weight, produces degenerative changes in a few, irregu- larly seattered, tubules. All the other tubules show apparently normal structure and spermatogenesis, although there is a general decrease in their size. The degenerative changes are initiated by a desquamation of the epithelial cells into the lumen of the seminiferous tubule, followed by pyenosis and karyolysis. The process involves first the spermatids and spermatozoa, then the secondary and primary spermatocytes, and finally the spermato- gonia. The Sertoli cells are the most resistant. During the degenerative process, multinucleated giant-cells arise, apparently by fusion of the degenerating spermatocytes. 5. During inanition, mitosis is very persistent in the seminifer- ous epithelium, both in young and adult rats. It may occur even in tubules where nearly all the cells are more or less degen- erated. Amitosis was not observed. A condition resembling synizesis was frequently observed in the spermatids in both con- trols and test rats. 6. Refeeding after prolonged inanition (beginning in rats at three weeks of age and extending to twelve to twenty’ weeks) results in a rapid improvement in the structure of the testis, although it may lag behind in weight for a while during the preliminary stages of reconstruction. Spermatogenesis returns to normal in a short time, the tubules gradually increase to nor- mal diameter, and spermatozoa appeared in thirty-seven days. EFFECTS OF INANITION UPON TESTIS—-ALBINO RAT 379 7. There is a definite hypertrophy of the interstitial tissue and an increase in the number of interstitial cells of the testis during the regenerative period on refeeding after inanition (in growing rats). No hypertrophy of the interstitial tissue was found accompanying atrophy of the seminiferous epithelium during inanition in either young or adult rats. The structure of the interstitial tissue and the size of the nuclei apparently remain nearly normal during acute and chronic inanition, except in extreme cases, where degenerative changes in the cells may occur. BIBLIOGRAPHY Auten, Ezra 1918 Studies on cell division in the albino rat (Mus norvegicus albinus). III. Spermatogenesis: The origin of the first spermatocytes and the organization of the chromosomes, including the accessory. Jour. Morph., vol. 31, pp. 133-186. 1919 Degeneration in the albino rat testis due to a diet deficient in the water-soluble vitamine, with a comparison of similar degeneration in rats differently treated and a consideration of the Sertoli tissue. Anat. Ree., vol. 16, pp. 93-117. BournerGarnier 1900 Altérations du tube séminifére au cours de V’alcoolisme expérimental chez le rat blane. C. R. Soc. Biol. (Cited by Mon- terosso, °12.) Corves, H. 1898 Untersuchungen iiber den Einfluss acuter und chronischer Allgemeinerkrankungen auf die Testikel, speciell auf die Spermato- genese, sowie Beobachtungen iiber das Auftreten von Fett in den Hoden. Virchow’s Arch., Bd. 151. 5 Dr Bruyne 1899 Signif. physiol. de l’amitose. C. R. Ass. Anat. Ire session. (Cited by Monterosso, ’12.) Donaupson, H. H. 1915 The rat. Reference tables and data for the albino rat and the Norway rat. Memoirs of The Wistar Institute of Anatomy and Biology, no. 6. Durcner, R. ApAms 1920 The nature and function of the antineuritie vita- mine. Proc. Nat. Acad. Sci., vol. 6, pp. 10-14. y. Epner, V. 1902 In Kélliker’s Handbuch der Gewebelehre, 3. Bd., 2. Halfte, 8. 415-416. Faucx, C. P. 1854 Beitrige zur Kenntnis der Wachsthumsgeschichte des Thierkérpers. Virchow’s Arch, Bd. 7, 8. 37. Gernartz, H. 1909 Geschlectsorgane und Hunger. 2. Mitteil. Centralbl. f. Physiol., Bd. 22, 8. 65-66. Granpis, V. 1889 La spermatogenése durant I’inanition. Arch. ital. de Biol, T. 12, pp. 680-682. Haar, S. 1915 Growth of the body and organs in albino rats fed with a lipoid-free ration, Anat. Rec., vol. 9, pp. 1-20. 380 DAVID M. SIPERSTEIN Jackson, C. M. 1915 Effects of acute and chronic inanition on the relative weights of the various organs and systems of adult albino rats. Am. Jour. Anat., vol. 18, pp. 75-116. 1915 2 Changes in the relative weights of the various parts, systems and organs of young albino rats held at constant body weight by un- derfeeding for various periods. Jour. Exp. Zoél., vol. 19, pp. 99-156. Jackson, C. M., anp Stewart, C. A. 1918 The effects of underfeeding and refeeding upon the growth of the various systems and organs of the body. Minnesota Medicine, vol. 1, pp. 403-414. 1919 On the recovery of normal weight in the various organs of albino rats upon refeeding after underfeeding from birth for various periods. Amer. Jour. Diseases of Children, vol. 17, pp. 329-352. 1920 The effects of inanition in the young upon the ultimate size of the body and of the various organs in the albino rat. Jour. Exp. Zodl., vol. 30, pp. 97-128. Kuntz, AtBerT 1919 Degeneration of testis in the dog. Anat. Rec., vol. 17. Kyrie, J. 1910 Ueber Entwicklungsstérungen der minnlichen Keimdriisen im Jugendalter. Wiener klin. Woch., Bd. 23. LoiseLt, Gustave 1901 Influence du jetine sur la spermatogénése. C. R. Soe. d. Biol., T. 53, p. 836. ManassEIn, W. 1868 Zur Lehre von der Inanition. Centralbl. f. d. med. Wissensch. (Berlin), Bd. 6, pp. 273-275. McCarrison, R. 1919 The pathogenesis of deficiency disease. Indian Jour. Med. Research, vol. 6, no. 3, pp. 275-355. (Also in Brit. Med. Jour., 1919, vol. 1, p. 177, and vol. 2, no. 3033.) (Abstracted in Jour. Am. Med. Ass., vol. 74, no. 12.) Miescuer, Fr. 1897 Histochemische und physiologische Arbeiten, Leipzig, Bd. 2, S. 116~217. Monterosso, Bruno 1912 L’azione del diguino e dell’estratto secco di tiroide sulla struttura dell’epitelio del tubo seminifero del topo. Archiv. de Biol., T. 27, pp. 35-62. Moreutis, 8., Hower, Pau E., anp Hawk, P. B. 1915 Studies on tissues of fasting animals. Biol. Bull., vol. 28, pp. 397-406. Morpurco, B. 1888 Sul processo fisiologico di neuformazione cellulare durante la inanizione acuta dell’organismo. Arch. per le sc. med., T. 12, pp 395-418. (Also in Arch. ital. de Biol., 1888, T. 11, pp. 118-133.) 1889 Ueber den physiologischen Zellneubildungsprocess wiihrend der acuten Inanition des Organismus. Ziegler’s Beitrige zur path. Anat. u. allg. Path., Bd. 4, S. 315-335. Nusssaum, £. 1996 Fortgesetzte Untersuchungen tiber den Einfluss des Hungers auf die Entwicklung der minnlichen Geschlechtsorgane der Rana fusca. Anat. Anz., Bd. 29, 8S. 315~316. PerRNIceE UND ScaGuiiost 1895 Ueber die Wirkung der Wasserentziehung auf Thiere. Virchow’s Arch., Bd. 139, S. 155-184. PoiarKoy, B. 1913 L’influence de jetine sur le travail des glandes sexuellesdu chien. (Communication préliminaire.) C. R. Soc. Biol. Paris, T. 74, pp. 141-143. EFFECTS OF INANITION UPON TESTIS--ALBINO RAT 381 Recaup et Tournape 1903 Notes hist. sur les phénom. régressifs détermines dans le test. par l’oblitération du canal déférent. C. R. Soc. de Biol. (Cited by Monterosso, '12.) Stmonowirtsco, J. 1896 Ueber pathologisch-anatomische Verinderungen der Hoden bei vollstiindigem und unvollstiindigem Hungern der Thier und Aufliitterung nach dem Hungern. (Cited by Mihlmann—Russiche Literatur iiber die Pathologie des Hungerns. Centralbl. f. allg. Path. u. Path. Anat., Bd. 10, 8. 160.) Srewarr, C. A. 1916 Growth of the body and of the various organs of young albino rats after inanition for various periods. Biol. Bull., vol. 31, pp. 16-51. 1918 Changes in the relative weight of the various parts, systems, and organs of young albino rats underfed for various periods. Jour. Exp. Zobl., vol. 25, pp. 301-353. Swinete, W. W. 1918 The effect of inanition upon the development of the germ glands and germ cells of frog larvae. Jour. Exp. Zodl., vol. 24, pp. 545-565. Traina, R. 1904 Ueber das Verhalten des Fettes und der Zellgranula bei chronischem Marasmus und akuten Hungerszustiinden. Ziegler’s Beitriige zur path. Anat. u. allg. Path., Bd. 35, S. 1-93. Voir, Cart 1866 Ueber die Verschiedenheiten der Eiweisszersetzung beim Hungern. Zeitschr. f. Biol., Bd. 2, S. 308-365. Voss, H. 1913 Zur Frage der Entwicklungsstérungen des kindlichen Hodens. Centralbl. f. allg. Path., ete., Bd. 24, No. 10, S. 433. THE ANATOMICAL RECORD, VOL, 20, No. 4 FIGURES AND EXPLANATION The drawings were made with the aid of a camera lucida. The unit of magnif- ication is 630 diameters for all the figures, with the single exception of figure 10, which has a magnification of 127 diameters. All the material stained with Hei- denhain’s iron-alum haematoxylin had been fixed in Carnoy’s fluid (no. 1). The remaining material had been fixed in either Bouin’s or Zenker’s fixatives. PLATE 1 EXPLANATION OF FIGURES Figures 1 to 7 show normal development in the epithelial wall and the growth of the tubules in albino rats from birth to eight weeks of age. All X 630. Figures 8 to 13 show changes in the seminiferous epithelium and size of the tubules brought about by experimental conditions. 1 Transverse section of a tubule from the testis of a normal newborn rat (Si 1.4). Section 6u thick; stained with iron-alum-haematoxylin and acid fuchsin. X 639. Note the presence of a single layer of parietal cells, P.C., and the large central cells, C.C., in the center of the tubule Each tubule is surrounded by a membrana propria, W.P. 2 Transverse sections of a tubule from the normal testis at four days (Si 2.5). Section 6u thick; stained with iron-alum-haematoxylin. X 630. The number of parietal cells, P.C., has increased, while the central cells, C.C., are less fre- quent. Membrana propria, W.P. 3 Transverse section of a tubule from the normal testis at seven days (Si 1.3). Section 6u thick; stained with iron-alum-haematoxylin. 630. Mitotie activity is apparent. A spermatogonium in metaphase is well shown, Sp.C. Germinative cells are all alike (Allen’s type A). Membrana propria, W.P. 4 Section of a tubule from the normal testis at fourteen days (Si 1.5). See- tion 6u thick; stained with iron-alum-haematoxylin and acid fuchsin. X 630. Cells of (Allen’s) types A and B are abundant and a few cells of type C are present, A., B., C. Sertoli cells, S.C., are beginning to assume their adult position and structure. Membrana propria, M.P. 5 Section of a tubule from a normal testis of twenty-one days (Si6.0). See- tion 10u thick; stained with iron-alum-haematoxylin. X 630. All types of cells, A., B., and C., are present. Primary spermatocytes, P.S., have appeared. Ser- toli cells, S.C. Membrana propria, M.P. Note the formation of a lumen, L., in the tubule. ; EFFECTS OF INANITION UPON TESTIS—ALBINO RAT PLATE 1 DAVID M, SIPERSTEIN LOS Sei} . \ 4 Y Gascon PO OC LNG SN SLRS Aone Vee : (G¥q—P.c. ed Ol ane Go Say RCoy a ee 2. \ WS OS a Sy ae SP CS OX ‘a eZ PLATE 2 EXPLANATION OF FIGURES 6 Section of a tubule from a normal testis at four weeks (K 8.1). Section 104 thick; stained with iron-alum-haematoxylin. X< 630. Presents the same picture as the preceding figure, but also shows a marked increase in the number of primary spermatocytes, P.S. : 7 Portion of a transverse section of a tubule from a normal testis at eight weeks (St 5.2). Section 104 thick; stained with iron-haematoxylin. X 630. Note the gradual transition from the spermatogonia to the mature spermatozoa. This corresponds very closely to the condition found in the adult testis. Sertoli cell, S.C.; spermatogonia, S.; primary spermatocytes, P.S.; secondary spermato- cytes, S.S.; spermatids, Spt.; spermatozoa, Sp.; membrana propria, M.P. 8 Section of three tubules from the testis of a rat four days old (Si 2.6) which had been subjected to acute inanition for fifty hours. Section 6x thick; stained with iron-alum-haematoxylin and acid fuchsin. X 630. Note that the structure resembles that of the newborn more closely than that normal at four days. Com- pare with figures 1 and 2. Central cells, C.C.; parietal cells, P.C.; membrana propria, M.P. PLATE 2 EFFECTS OF INANITION UPON TESTIS—ALBINO RAT DAVID M. SIPERSTEIN ny GD ss SG; la; en: s i‘ re aei\3> PLATE 3 EXPLANATION OF FIGURES 9 Section of a tubule from a rat (S 7.32) held at constant body weight by underfeeding from three to ten weeks of age. Section 6u thick; stained with haematoxylin and eosin. X 630. Degenerating primary spermatocytes, D.P.S., showing the homogeneous, deeply acidophilic staining reaction of the cytoplasm. Note the persistence of mitotic figures, /.F.; the normal Sertoli cells, S.C., and spermatogonia, S. A multinucleated cell, Wu.C., typical of those appearing as a result of chronic inanition. Degenerating cytoplasm, D.C.; membrana propria, M.P. 10 Section of a portion of the atrophic testis from a rat (S 11.65) subjected to chronic inanition from three to ten weeks of age. Section 1(u thick; stained with haematoxylin and eosin. X 127. The central tubule shows the extreme stage of degeneration (described in text), a complete nearly homogeneous mass of necrotic tissue. The surrounding tubules show various stages of degeneration. Note the mitotic figures, M.F., in the tubule to the right and the apparently normal Sertoli cells, S.C. A slight hyperplasia of the interstitial cells, J.C., appears. Blood-vessel, B.V. 11 Portion of a tubule from the testis of a rat (St 44.4) stunted by under- feeding from three weeks to 428 days of age. Section 1(u thick; stained with haematoxylin and eosin. X 6380. Note the degenerating primary spermato- cytes, D.P.S.; the multinucleated cell, Mu.C., in the lumen. Sertoli cells, S.C., and spermatogonia, S., are apparently normal. Membrana propria, M.P. EFFECTS OF INANITION UPON TESTIS—ALBINO RAT PLATE 3 DAVID M, SIPERSTEIN 387 PLATE 4 EXPLANATION OF FIGURES 12 Oblique section of a testis from an adult rat (S 25) subjected to acute inanition for nine days. Section 10 thick; stained with haematoxylin and eosin. XX 630. Multinucleated giant-cells, M.G.C., occupy the center of the tubule. Débris composed of degenerating cells of various kinds fills the tubule. Spermatozoa, Sp.; spermatids, Spl.; spermatogonia, S.; membrana propria, M.P. The Sertoli cells, S.C., still oceupy their normal position, but show atrophic and degenerative changes. 13. Portion of transverse section of the testis from a rat (S 12.52) underfed from three to ten weeks of age and then refed for thirty-seven days. Section 7 thick; stained with haematoxylin and eosin. 630. Note the large number of normal primary spermatocytes, P.S., and spermatozoa, Sp. Spermatogonia, S., showing mitotic figures, are abundant. Sertoli cell, S.C.; membrana propria, M.P. SSS EFFECTS OF INANITION UPON TESTIS—ALBINO RAT PLATE 4 DAVID M, SIPERSTEIN 389 PLATE 5 EXPLANATION OF FIGURES 14 A to F represent various stages in the interstitial (mesenchymal) cells of the testis during normal development, inanition, and refeeding. All magnified X 630. A, normal newborn (Si 1.4). B, normal adult (S 14). C, underfeeding, three to ten weeks of age (S. 7.32). D, extreme atrophy in underfeeding from three to ten weeks of age (S 11.65). EF, underfeeding from three weeks to 428 days of age (St. 44.4). F, refed thirty-seven days after underfeeding from three to ten weeks of age (S. 12.52). 390 EFFECTS OF INANITION UPON TESTIS—ALBINO RAT PLATE 5 DAVID M. SIPERSTEIN & / @ © 4 q x $= CS? A. B & ,% f) ey 4 § ¢ @ aes Qe € j eo ef eal PEN & 2 c 3 @ 301 Resumen por los autores Bradley M. Patten y Rees Philpott. Western Reserve University, School of Medicine. La contraccién de los embriones durante los procesos prepara- torios a la obtencién de cortes. Para averiguar el grado de contraccién producido al fijar material embriolégico y prepararle para la obtencién de cortes, los autores han llevado a cabo varias series de medidas en em- briones de cerdo durante los diversos momentos de algunos de los procederes comunes. Los fijadores usados fueron los sigui- entes: Licores de Zenker, Orth, y Tellyesnicky; formol al 10%, formal-aleohol y licor de Bouin. Primero se midié la longitud del embrién desde la curvatura cefdlica hasta la lumbar, cuando aquél estaba atin contenido en el liquido amniético, y después a raiz del uso de cada una de las soluciones con que fué tratado. La contraccién media fué medida en tantos por ciento de la longitud primitiva del embrién. Estas medidas fueron repre- sentadas grificamente por curvas que indican el grado de con- traccion en cada uno de los momentos de la técnica empleada. La mayor contraccién aparece después de la fijacién con los liquidos que contienen bicromato, tales como los licores de Zenker, Orth y Tellyesnicky, y la disminucién de la longitud del embrién varia desde el 30°% en embriones de 10 mm. hasta préximamente el 20% en los embriones de 20 a 25 mm. El grado mayor de contraccién en los embriones mis jévenes debe probablemente atribuirse a la menor compacidad de su meso- dermo. La mayor parte de la contraccién en estos métodos es causada por los fijadores. La fijacién en formol al 10% y en formol alcohol produce un hinchamiento inicial, al cual sigue una contracci6én rapida durante la deshidratacién. La contrae- cin total después de la inclusién en parafina es proximamente igual 4 la producida por las soluciones de bicromato. La con- traccién después del licor de Bouin es ligera, pero contintia durante la deshidrataci6n e inclusién. La contracién total con este método es algo menor que la de los fijadores que contienen bicromato. La comparacién de las diferentes grificas indica una tendencia mayor hacia el aumento de la contraccién durante la deshidratacién despues de los fijadores que producen menos contraccién inicial. Esto practicamente anula, por los menos en el caso del material destinado a la inclusién en parafina, las supuestas ventajas de los fijadores mezclados con el fin de evitar la contracci6n por el fijador mismo. Translation by José F, Nonidez ftir all Bie aiae i a a > a AUTHORS’ ABSTRACT OF THIS PAPER ISSUED BY THE BIBLIOGRAPHIC SERVICE, DECEMBER 27 THE SHRINKAGE OF EMBRYOS IN THE PROCESSES PREPARATORY TO SECTIONING BRADLEY M. PATTEN AND REES PHILPOTT Laboratory of Histology and Embryology of Western Reserve University, School of Medicine EIGHT FIGURES INTRODUCTION The true or fertilization age of the human embryos which come into the laboratory is usually uncertain if not altogether unknown. For the most part the age of other mammalian embryos used for laboratory study is equally a matter of con- jecture. For this reason it is customary to designate the stage of development attained by an embryo by giving its measure- ments. In this country the method of measuring embryos used by Mall is in quite general use (Keibel and Mall, ’10, vol. 1, ch. 8). If embryos always came into the hands of the investigator fresh, so that the measurements might be made under uniform condition, the methods in use would leave little to be desired, at least as far as establishing a basis for comparing different embryos is concerned. Unfortunately, however, embryos are brought into the laboratory in various stages of preservation or lack of it. The shrinkage of embryos under the various treatments to which they are subjected for preservation and in preparation for sectioning makes the comparison of embryos measured at different steps in the processes a precarious matter. While the fact that shrinkage is to be expected is a matter of common information, we have been unable to find in the literature any quantitative data covering the shrinkage which is to be encountered in the various processes of fixation com- monly in use for embryological material. The measurements 393 394 BRADLEY M. PATTEN AND REES PHILPOTT described in this paper were made to ascertain how much shrink- age occurs in the various steps of some of the more common methods of preserving embryos and preparing them for section- ing. Because linear dimensions are already in use as a criterion of the stage of development attained, they were used, rather than weight or volume, as a basis for determining the shrinkage. It is hoped that these measurements and the further accumulation of similar data will aid in more accurate comparisons of embryos which come into the hands of investigators in widely different stages and conditions of preservation. MATERIAL AND METHODS By reason of the readiness with which they could be secured fresh, and because of their close comparability with young human embryos, pig embryos were used for the entire series of measurements. The embryos were measured first in amniotic fluid,! immedi- ately on removal from the uterus. The measurements made were for the crown-rump length. The belly thickness was also measured in quite an extensive series as a check against the possibility that distortion of the spinal axis might be affecting the length measurements. Inasmuch as the shrinkage in per cent of the original dimensions corresponded fairly closely in the two cases, only the crown-rump measurements are here recorded. All the measurements were made with micrometer calipers graduated in millimeters and indicating the tenths of a mill- meter by vernier. In the early part of the work both of us measured the same embryos independently and compared our results. Our measure- ments tallied so consistently to the tenth of a millimeter that in the latter part of the series measurements were made by only one observer. After the first. measurement in the amniotic fluid, embryos were measured after each solution with which they were treated. 1 Some embryos were measured also in physiological saline solution and their measurements compared with those made in the amniotic fluid. The measure- ments in the two fluids were identical. SHRINKAGE OF EMBRYOS IN FIXATION 395 Following paraffin infiltration the embryos were transferred from the molten paraffin to xylol for measurement, after which they were at once returned to paraffin for a few minutes before embedding. This process proved to be in no way detrimental to the infiltration or embedding. Measurements were later carried out on several series of sagittal sections made from the embryos measured during the preliminary processes of preparation. When care is used in expanding the sections on the slide, their measurements corre- respond to the measurements made subsequent to paraffin infiltration. MEASUREMENTS Since the processes to which the embryos were subjected, and therefore the series of measurements made on them, differ in accordance with the fixing fluid, the data secured may be most simply presented under the heading of the fixing agent used. Zenker’s fluid (formula as given in Lee, ’13) The technique employed was not different from that com- monly used with Zenker’s fluid: twenty-four hours in fixative; overnight washing in running water; about four hours in each grade of the ascending alcohols up to 70 per cent; twenty-four hours in 70 per cent alcohol containing Lugol’s solution for the removal of any remaining mercuric chloride; overnight in 95 per cent alcohol; four hours in absolute (two changes); three hours in xylol; two to three hours in soft, and two to three hours in hard paraffin, according to the size of the embryos. The measurements made on Zenker-fixed embryos are given in detail in table 1 and summarized graphically in the curve of figure 1, To facilitate comparisons for variability, the material in table 1 has been arranged in the order of the lengths of the embryos when measured fresh in the amniotic fluid. 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The arrangement of the measurements in order of the original length of the embryos brings out another point. The total shrinkage is greater in the younger embryos than in the older. While it would be unsafe to draw any final conclusions from data based on embryos of the limited size range here studied, it seems probable that this difference in shrinkage is due largely to the differences in the organization of the developing muscular and connective tissues. In embryos of about 10 mm. the mesodermal tissues are represented for the most part by loosely aggregated cell masses with abundant interstitial spaces. By the time the embryo has attained a length of 20 to 25 mm. the cells of the developing muscular and connective tissues have become much more compact with a corresponding reduction of the interstitial spaces. Moreover, in the older embryos chondri- fication has begun in many centers and renders the body of the embryo more rigid as well as more compact. These conditions would seem quite sufficient to account for the fact that fixation and dehydration of very young embryos result in a greater shrinkage than that induced in older embryos. The extent to which shrinkage varies with the original length of the embryo is shown graphically in figure 2. The curve is not as precisely indicated as it would be by a larger number of cases, but its general course is nevertheless quite apparent. Only measurements of embryos fixed in bichromate fluids were used in plotting this curye since their shrinkage is closely compar- able, whereas some of the other fixing fluids show quite different’ shrinkage curves. It was thought possible that preliminary coagulation of embryos by treatment in hot water might reduce the amount of shrinkage they suffered. To test this possibility, embryos were immersed for five minutes in water of 65°C. and then put through the routine Zenker process. As will be seen by comparing the curves of figures 1 and 3, this preliminary treatment with hot water proved to be ineffective in reducing the amount of shrinkage. eters Im 25 20 Ee Sesesssesiis 15 10 Original Length of Embryos in Mill or BEE Se SeSSGGSGGGRSRGGRGGRSRREERe~SLAr-s co eS SSSR URERSSRERSSSESS EES Boise Eee eee EEE EEE eee ee Yer) —) wn o Juadiog ut oBeyurys peyoy 5 = ™N ! | nr A 401 SHRINKAGE OF EMBRYOS IN FIXATION “UU gS] JO YIAue] [wUIALIO oAVIOAT uv Furavy sodaquia usazy Jo SpUoMINSvOUL OABIOAT OY} UO paseq SI PAIN OYJ, “1OxWOZ UL UoOIssoUTUT asojoq ASNE *H, GO IV 407UAM YATE SOZNUTUT 9AY OJ JUOUTAwAIy Aq Payrpour poyjoUL JoyOZ oyy UE pay vatqns o190M Soy? YOUN 07 suoIyNTOS snorswa oy Aq soArqmo Bid ur poonpur oseyurays oy} Aurmoys yduir ¢ “By ‘oiquid o[BUIs B JO SPUMIOANSvOUL OY} WOIy poyvOoT SI yuIOd You “OAIquIO 944 Jo « U7 YIU SoUIBA Bu -uo1joos 10y uoTyavdosd Burunp sodaquio Jo oPVYULAYS [8}O} OY} YON 07 4U9}XO OYA BUIMOYS BAIN Z ‘By € 3 U0r}PAvdaIg JO SoBVIG DATSSIDWNG UT SpuoUTIINSPIW "\70H 2 US ] oe = eyULA Lae 8 pa ceeseue = wap age aittes: CCASBRBERGGE SeEDEEEE = oo so ial gues Baease 2. HA 8 ; HEE x > © la} bt wo. _ ii x00" 402 BRADLEY M. PATTEN AND RBEES PHILPOTT The slightly less extensive shrinkage shown by the embryos treated with hot water before fixation, if significant at all, is attributable rather to the fact that their average length (18.6 mm.) was somewhat greater than the average length (16.1 mm.) of the embryos treated by Zenker alone. Orth’s fluid (formula as given in Lee, ’13) The technique employed with embryos fixed in Orth’s fluid and the times the embryos were allowed to remain in the different solutions were essentially the same as that described for Zenker’s solution except for the omission of the iodine treatment. The results of the measurements were tabulated as for the embryos fixed in Zenker, but since the measurements were of the same character as those given in table 1 they have not been given in detail. Figure 4 summarizes the results graphically. The presence of formalin in Orth’s fluid might be expected to lessen the shrinkage to a certain extent. Such is apparently the ease, for the shrinkage in this fixative is noticeably less extensive than that in Zenker (compare fig. 4 with figs. 1 and 3). When, ’ however, we follow out the curve, we find that the advantage is only temporary. There is a greater shrinkage in dehydration following fixation by Orth than in dehydration following Zenker fixation. The total shrinkage encountered in the two techniques is virtually identical. The transitory nature of the swelling effect of formalin fixation when it is followed by dehydration is shown much more strikingly by the data given below for formalin uncombined with other solutions. Tellyesnicky’s fluid (formula as given in Minot, ’11) The technique following fixation in Tellyesnicky’s fluid was similar to that used for Zenker and Orth material. The results of the measurements are summarized in the curve of figure 5, The slightly smaller amount of shrinkage indicated on the Tell- yesnicky curve as compared with the other bichromate fixatives is not sufficient to be regarded as significant. Both as regards the total amount of shrinkage induced and the stage of the process 403 SHRINKAGE OF EMBRYOS IN FIXATION “q)8u9] [eULTIO “uIUT 2-6] Dusvs9Av soArquia auO0-AyUIMy JO S}uUIOINSvoM aAVIVAB JY} WIOIJ pIywOO] 919M BAIN ay} uo syurod oy, “pring 8.4740 UI UOeXY Zurmojjoy soArquio Aid ur poonpur eduyuLsys oyy Aurmoys yduiry p Ay uoneiedsig Jo S2HRIG onNISSIDINg UL syUSUIaINsPI~W IS L.A =) ul odeyu 8 z 3 ua] [PUIDUIO Jo % 3 yo PATTEN AND REES PHILPOTT BRADLEY M. 404 “YyBug] [vaso “uIUL gg] Zursvs9aw ‘soLaquio anoj-AyUOMg JO spuouTBANSvaUI OFBIOAT oY} WIOL] pozTooy] 49M OAIND 94} uO syurod ayy, “pray 8, Ayorusedyjay, ut uolyexy Surmopjoy soAaquio Bid Ul pooNpUr odvyUIAYs OY} Buraoys ydery ¢ “Fry uornPesedaig jo seSRIS DAISSADONG Ul spyUIWLIINSeVsyw : 0g N a : | seat H at ~ Hote HH H 69a Pet auip Ss (% ete bs atte 5 rH ae : 062, i 2 : we: ‘2 =H 9B ti o Bes aN, 01 = SHRINKAGE OF EMBRYOS IN FIXATION 405 at which the shrinkage takes place, Tellyesnicky, Orth, and Zenker material behave essentially alike.’ Formalin (10 per cent commercial formalin) Embryos were fixed in formalin for twenty-four hours, trans- ferred to 70 per cent alcohol overnight, left in 95 per cent alcohol twenty-four hours, in absolute (two changes) four hours, in xylol three hours, in soft paraffin two to three hours, and in hard paraffin two to three hours, according to their size. The measurements of the embryos at various stages in the process are given in detail in table 2 and summarized in the graph of figure 6. The most striking thing that the measure- ments for formalin fixed embryos bring out is the fact that the initial swelling induced by the formalin is not only rapidly lost on treatment with alcohols, but gives way to marked shrinkage. In fact, the shrinkage of formalin-fixed material during dehy- dration is more extreme than the shrinkage encountered in dehy- dration following the other fixatives we used. While, therefore, formalin fixation causes an initial swelling, the ensuing processes of dehydration and infiltration result in a final shrinkage which is approximately the same as that in the bichromate processes. Schultz (’19) found for foetuses, as did Hrdlicka (’06) and King (713) for brain material, that the initial swelling effect of formalin fixation tended to become less marked with continued storage in formalin. Although long periods in formalin reduced the initial swelling, it still left their material increased in weight as com- pared with its fresh condition, producing nothing approach- ing the shrinkage we found to be caused by dehydration of formalin-fixed embryos. In regard to dimensions, Schultz found considerable varia- bility, some measurements showing a slight decrease and others 2 For adult brain material Donaldson ('94), King (’10), and Plant (‘18) found an increase in weight and volume following treatment with bichromate solutions. This is in marked contrast to our findings for embryos. The difference between adult brain tissue with its compactness and high myelin content and young em- bryos with their loosely organized structures might possibly account for their divergent reaction in fixatives. 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The points on the curve were located from the average measurements of twenty-two embryos, averaging 17.7 mm., original length. Individual measurements for the same group of embryos are given in table 2. 408 BRADLEY M. PATTEN AND REES PHILPOTT Formol-alcohol There are various mixtures of formalin and aleohol in use as fixatives. The formula we used was: Formalin, :(commeraial) .-. yu sueaents Cech atone Jeicory -Meanabee «