THE “DE OVORUM GALLINACEORUM GENERATIONIS PRIMO EXORDIO PROGRESSUQUE, ET PULLI GALLINACEI CREATIONS ORDINE” OF VOLCHER COITER

TRANSLATED AND EDITED WITH NOTES AND INTRODUCTION BY HOWARD B. ADELMANN, PH.D.

ITHACA, N. Y.

Part ii. Conclusion* As for myself, in May 1564 at In the middle I saw something resem­ Bologna, stimulated by Doctor bling semen.25 The point and the circle Ulysses Aldrovandus (that most were found under the membrane sur­ distinguished professor of ordi­ rounding the substance of the egg. They nary philosophy, a man expert in the were bestrewn with certain sanguineous knowledge of the various sciences and filaments. The white, like the yolk, was a arts as well as of philosophy and especi­ little more fluid than usual. The white ally natural philosophy, my encourager glass-like substance,26 which is com­ and teacher to be cherished with per­ monly held to be the semen of the cock, petual regard), and encouraged by other was a little harder. teachers and students, I had selected No change in the albumen was detected two clucking hens ready for incubation. on the third day;27 but the sanguineous Under each of them I had placed twenty- point or globule previously found in the three eggs17 and in the presence of those yolk, but now found rather in the albu­ men, I opened one on each day, in order men,28 manifestly pulsated29 and, as we that we might determine these two things were able to judge by the color, gave rise especially, to wit—the origin of the veins to one venous trunk which, after dividing and what is first formed in the animal.18 into two,30 gave off many small branches In an egg of the first day19 I saw that which encircled the pulsating point. These the yolk had acquired a white circle which small branches were supported by a very was not very large. In its middle there thin membrane which represented the was a point or disc of the same color. secundine31 both in function and sub­ From the circle two similar circles20 stance. Hence three membranes were flowed away. One of them was thicker and found here; the first32 is assigned to the longer than the other. The yolk was more shell, the second33 to the whole substance fluid than the yolk of a fresh egg. of the egg and the third to the secundine.31 On the second day21 I saw two very On the fourth day I opened the egg thin pellicles or membranes, one of which from the blunter end and there occurred adhered immediately to the shell;22 the first a space so empty that it easily other, which surrounded the substance admitted the first joint of the finger. of the egg, was separated a little from the The aqueous white, on account of its shell,23 for a small space at the end of the tenuity, flowed off. The globule and the egg was empty. The yolk had risen other structures were found to be larger. toward the pointed end of the egg as Moreover, the globule pulsated; the Aristotle24 says happens on the third vessels did not. On one side,34 three day. The middle part of the yolk was translucid, glass-like globules were found seen to be clearer than the remaining joined to one another. On the other side portion. there were two branches or vessels,35 * Part i appeared in the July issue of the Annals of Medical History, n.s. 5:327, 1933. not unlike arteries; which, however, did There was nothing more perfect or larger not pulsate. When the albumen had been than the eyes. For, although I had some poured off, the rather liquid yolk came difficulty, I was able to distinguish from into view. It was besprinkled here and one another all the tunics and humors in there indiscriminately with blood. the eyes. Hence from the fact that in On the fifth day we observed that the birds the eyes are developed first, Lac- second membrane, surrounding the whole tantius Firmianus43 decided, not without substance of the egg and perfused with reason, that the head begins to develop many veins,36 was so free from the shell­ first in birds. Perhaps the eyes, just as membrane and so strong that, without very ingenious and elaborate instruments, injury, it could be removed together require a long time for completion. with the substance of the egg. When Wherefore, since birds remain in the this membrane was opened, I saw that egg for a short time, the creator of things the sanguineous, pulsating globule had commences to weave this fabric first with sunk more deeply than usual. I took an the eyes. Furthermore, superiorly between egg of the fifth day from each hen. There the eyes there was a rather large, trans­ appeared in one of them merely the still parent globule which has been seen to formless pulsating globule which was, represent the brain. Below the eyes there however, surrounded by blood vessels, was something resembling a beak. as has been stated. The lateral globules37 On the seventh day everything could tended to be black in color. Between be seen more clearly; first, the three them there were still smaller connected pellicles, especially the third called the globules,38 which represented the brain secundine44 which supports the veins and after a fashion. The third globule39 was surrounds all the fluid. When the yellow­ unchanged except in size. In the albumen ish white fluid had been poured off, the dissimilar parts were seen. Some were small, rudely-formed animal appeared. thin and approached glossy whiteness, Its head was larger and more perfect others were denser. The yolk was easily than the other parts of the body. Both mixed with the albumen. In the other egg the cranium and the beak were observed the head of the chick clearly appeared to be more perfect. The rest of the body very large with respect to the size of the and its members were formless. I was body. On both sides of it there was a able to distinguish almost none of the blackish eye, which was found to be very viscera both because they were included clear in the middle. Between the eyes in the thorax and because internally there was a third globule.40 The rest of they had not yet attained their true the rather long body hung down from and manifest form, for they were seen the head. The heart or pulsating disc was to be in disorder everywhere. situated not far from the head. From it On the eighth day I found that all the veins were seen to arise. I was able parts including the legs and wings were to find no trace of the liver, so confused larger and better formed, so that the were the viscera. embryo already exhibited the likeness On the sixth day, in addition to the of a chick. It moved around in the other parts which were all larger, we albumen45 with more vigorous motion. saw from the blunter end, after the In addition I found rather conspicuous . . . 41 of the membranes or pellicles, veins46 entering the umbilicus of the the albumen first, for the yolk remained chick. in the bottom of the egg. The living, On the ninth day I observed that the animate chick, imperfectly delineated in secundine4' had increased with respect all its parts, floated in the albumen.42 to the number and size of its veins. It had been granted a head which was In short, it was more distended with blood very large in proportion to the body. than usual; some very thin blood had even transuded. After the secundine, and was white in color like the spermatic the chick was visible floating in the parts.56 The lung and the ribs were white with half of the yolk on each side formed. In the lower part of the belly as if the yolk had been cut into two equal were the liver which tended from white parts.48 The umbilical vessels were much to reddish in color, the stomach and the larger. After the chick had been taken intestines which were very white. Two out, I removed the proper membrane49 umbilical vessels57 emerged from the immediately surrounding the chick so belly of the fetus next the anus and that it might not perish in the liquid. proceeded to the yolk. When the chick The chick was now perfect in all parts had been removed, we noticed that and it was observed to have large pores the greater part of the albumen had been everywhere, from which the primordia used up and what remained was a dense of feathers were about to emerge. The excrement. Little of the yolk, however, head was largest of all. The eyes were had disappeared. very perfect indeed and provided with On the eleventh day we found no lids. I saw three transparent globules difference except in size. The head had in the head, the combination producing grown more evident and the feathers the form of the avian brain. All parts had sprouted a little. The fetus, resting below the neck had attained their com­ upon the yolk, floated in a white and plete and natural form. A pulsation tenuous albumen.58 The dense and viscid appeared externally in the thorax in albumen adhered below the yolk. the region of the heart. The heart had On the twelfth day, in addition to attained its form and was whitish in other things we examined the membranes color. Moreover it beat for a long time and humors. There were four membranes. outside the chick.50 The rather pale The first59 was fused with the shell for liver, the stomach, the intestines, the the sake of strength, for so strongly does ribs and all the other viscera were found it hold the very fragile shell together to be very soft and flaccid. There were that a fresh, even a raw egg, cannot be two albuminous substances and each broken by even the strongest man if was surrounded by its own individual the pointed ends are compressed by membrane.51 One portion52 was trans­ both hands. The second membrane60 parent and contained the chick swim­ surrounds the entire substance of the ming in it. The other, viscous, dense egg. It is depressed and contracted for and pale, the excrementitious portion the diminution and contraction of the egg. of the albumen, as it were, remained in In this way it prevents the mingling the bottom of the egg. of parts of the egg which could easily An egg of the tenth day had a secun­ be brought about by shaking since dine53 somewhat stronger than usual everything becomes more liquid during and veins bedewed with blood on the incubation. The third membrane61 affords outside. The fetus, which lay upon the a support for the veins and arteries, for yolk as on a couch, was perfect in all it is full of arteries and veins. Moistened its parts. The legs, the back and the externally by tenuous blood, it surrounds buttocks were covered with the primordia the whole egg and performs the function of feathers. The body or belly of the of the secundine. The third membrane chick was now larger than the head. is followed by the membrane62 proper Aristotle54 states the contrary. In the eyes to the chick, which contains not a little I saw all the tunics, all the humors, and water in addition to the chick. It seemed the external covers or lids as well as the to me that this tunic or membrane is membrane with which they wink.55 The dilated next to the umbilicus and that brain had its convolutions and gyri. it invests the umbilical vessels. As for The heart, indeed, had its natural form the chick, it was larger and more solid and was covered with larger feathers. one membrane75 which arose from the Something white adhered loosely to umbilicus or skin of the chick. The rest the end of the upper and Iowrer bill.63 corresponded to what has already been Women say that this prevents the picking described. of grain and for this reason they remove On the sixteenth day I saw that the the white substance as soon as the chicks dense and viscous portion of the albumen have hatched. had been used up almost everywhere On the thirteenth day we saw that and that the branch of the pulsating the substance of the egg was diminished artery was distributed throughout the in quantity. The chick was larger and membrane surrounding the yolk. The more completely feathered. Besides these membrane of the chick and of the yolk things there was nothing extraordinary. were the same as formerly. Other things On the fourteenth day the chick had which should have grown were observed grown in proportion to the degree to to be larger; those which should have which the albumen had disappeared. diminished in size were seen to be smaller. It was entirely covered with small Among other things, the belly was much feathers. The transparent, dense and more swollen and thicker than usual. viscous fluid, smaller in quantity than Within the belly, the viscera had grown usual, was contained in its own mem­ very much. In the stomach I found a brane64 just as the yolk was contained chyle-like substance, the major portion in a pellicle65 full of vessels. The umbilical of which, however, was in the end of vessels seemed to me to be five in num­ the esophagus next to the stomach. ber. One vein66 ran to the third membrane Two worm-like vessels which resembled or secundine67 to which it supplied many intestines rather than arteries, hung branches, but two other veins68 were down outside the belly.76 distributed throughout the tunic invest­ On the seventeenth day I saw an ing the yolk. In addition to these veins, aqueous substance, scanty in amount I found among the umbilical vessels two both between the third and fourth small arteries which, coiled like worms,69 membranes77 and between the fourth extended to the yolk. I was unable to and the chick.78 And then I saw emerge observe their attachment. from the umbilicus one artery, three On the fifteenth day the vessels were veins79 and an outgrowth80 from the scattered everywhere through the secun­ intestines to the yolk. Two of the veins dine.70 They had tunics so thin that they entered the mesenteric veins. The third were injured by slight contact with the went to the vena cava. The large artery, knife. Very red, thin blood flowed out. passing by the stomach opened into These vessels or veins proceeded from the heart as I saw at times. I saw the one rather thick trunk,71 which extended intestines hanging out of the umbilicus76 for a long distance through the middle for some distance and passages81 extend­ of the chorion.72 When the secundine ing from the intestines to the yolk of was cut open, no little watery serum the egg. Very hard, shell-like feces were flowed out. Then there came into view observed between the fourth membrane the vesicle or membrane73 in which the and the chick. In the stomach some fetus lay floating in water, and likewise chyle, mixed with water was found. No the yolk, covered by its own membrane. little yolk had been drawn into the belly. This membrane was fused to the secun­ Its disposition and location corresponded dine just as in the human fetus the to the description of Aristotle.82 amnion is fused to the chorion.74 The On the eighteenth day I noticed some vitellus was clearly divided into two true excrement from the chick between parts which cohered for half a finger’s the fourth membrane and the chick. breadth, but for both parts there was The fourth membrane83 surrounded the yolk and the chick. The chick was When the opening was dilated with completely feathered and pot-bellied. a knife, the yolk emerged invested with When the membrane belonging to the its own membrane and drawn out in chick was separated I found that the length. There was a smaller amount of membrane proper to the yolk84 was yolk than at the beginning. It was joined fdled with many veins and that in its to the intestines by means of a canal92 middle portion it had been pulled into prolonged from them. The umbilical the belly together with the yolk, now artery, which was mentioned in an drawn out in length. The viscous white egg of the seventeenth day was observed substance which has been mentioned to pulsate much more clearly than was entirely used up. Within the chick, before, and to open into the heart.93 the stomach, which had grown very Two veins94 joined branches of the much, contained a little aqueous fluid portal vein far from the liver. From and a great deal of a white, cheesy the stomach, when cut open, there substance which we thought was chyle. flowed out chyle which was much yellower Some such substance, indeed, flowed than usual, and a little water. Water from the intestines. flowed from the crop and greenish feces On the nineteenth day the head of from the rectum. The color of the liver the chick was bent down and concealed tended to be yellow rather than reddish. under the right wing and leg. The The lung was reddish. aqueous fluid had diminished everywhere. Between the fourth tunic and the chick Notes (Continued) there were encountered true feces as well as a watery fluid with which the 17. See Hippocrates,1141. 7, p. 531: “Take whole chick was wet. The membrane twenty or more eggs, and give them to of the yolk85 was clearly seen to arise two or several hens to cover; then each from the skin of the chick. The yolk day from the second to the last, that was seen, by the contraction of this of hatching, remove an egg, open it membrane, to be drawn inside and and examine it; you will find that absorbed;86 indeed it had now been everything conforms to what I have almost absorbed. In addition to this said, insofar as one can compare the improper membrane,85 the yolk had also nature of a bird to that of man.” There can be little doubt that the a proper one87 filled with many veins foregoing passage inspired the re­ and arteries. We saw in the belly the searches of Aldrovandus, who quotes things which we had seen before but it and after referring to the divergent they were more perfect. I found no yolk views of Aristotle and Galen says: “In in the intestines (as Albertus Magnus88 order to obtain the truth regarding this would have it). The chick already had trivial controversy between physicians testes and a comb, for it was a cock. and philosophers, with the greatest Furthermore, we heard peeping. diligence and curiosity I dissected daily On the twentieth day the chick was one of twenty-two eggs which were being fully formed. Within the shell were incubated by a hen and I found that found four membranes89 or tunics at­ Aristotle’s doctrine is very true ...” (Ref. 96, vol. 2, p. 216.) tached to one another at one place. As pointed out in the Introduction, The inner two90 of these membranes Coiter was doubtless influenced by this contained many veins and arteries. As passage from Hippocrates, either di­ for the chick, we saw three umbilical rectly or through Aldrovandus. vessels inside. Two of these seemed to 18. As Bloch102 points out, this was a be arteries, one a vein.91 The umbilical question with which the early writers opening was closed, but it could easily on generation were deeply concerned. be opened when a probe was introduced. Unfortunately their conclusions were too frequently influenced by purely philo­ the part below is both smaller and less sophical considerations and often not differentiated. [Ref. 97, 7416, 25.] based upon observation. Thus AIc- “ . . . that part which contains the maeon of Croton is quoted as having first principle comes into being first, said that the head arises first during de­ next to this the upper half of the body. velopment because it contains the brain, This is why the parts about the head, the seat of the soul (Wachtler,138 pp. 66- and particularly the eyes, appear largest 67). Similarly, Censorinus103 states that in the embryo at an early stage, while Anaxagoras taught that the brain, the the parts below the umbilicus, as the seat of sensation, appears first (Cen­ legs, are small ...” [Ref. 97, 7426.] sorinus, vi). According to Censorinus “The bones, sinews, hair, nails, the belly and the head “because they hoofs and the like are the last parts to contain the most void” were held to assume their form.” (Ref. 97, 7446.) appear earliest in development by Pliny’s account leans heavily on Democritus but Plutarch attributes to Aristotle’s teaching (Ref. 125, lib. x, him the doctrine that the navel is the c. 53) but Galen asserts (Ref. no, vol. first structure to appear (Plutarch,126 4, pp. 662-664) that the heart arises cap. iii ); and Aristotle97 (740a) states after the liver. that he held that the external parts Avicenna’s account (see de Koning," precede the internal parts in develop­ pp. 754-764) is rather confused: “the ment. Hippon was another adherent first thing formed which shows dis­ of the doctrine of the primacy of the tinctly is the umbilicus, but the swell­ head in development (Censorinus vi). ings of the heart, liver and brain precede Somewhat later, Lactantius states “in the formation of the umbilical cord, the fetuses of birds, however, there is although the complete formation of no doubt that the eyes are formed first these three organs takes place after as we have often observed in eggs. the complete formation of the substance Whence, I think that it cannot be of the umbilical cord . . . The truth otherwise than that development begins is that the first organ to form is the with the head.” (Ref. 119, p. 78.) heart.” Empedocles was the first to teach Albertus Magnus is influenced by that the heart arises first because it both Aristotle and Avicenna, affirming contains life in the highest degree that three vesicles for the heart, liver (Censorinus, vi). and brain arise in the order stated In the Hippocratic treatise “On (Ref. 95, lib. 9, tr. 2, cap. 4: 117, p. 721). Regimen” it is stated that all the parts Aldrovandus (Ref. 96, vol. 2, p. 217) of the fetus are simultaneously formed and Coiter both describe the early (Ref. 114, t. 6, p. 499, ^[26) but the origin of the heart but Fabricius “De Carne” describes the formation characteristically argues (Ref. 107) of the organs in purely arbitrary that the skeletal system (the vertebral sequence (see Bloch,102 p. 227ff.). column, cranium and ribs) arises first According to Aristotle, “ ... in the because the other parts are supported embryo all the parts exist potentially by it. Next appear the brain and spinal in a way at the same time, but the first cord and later the heart, liver, etc. principle is furthest on the road to Harvey (Ref. 112, p. 373) believes realization. Therefore the heart is first that the blood is first formed, preceding differentiated in actuality. [Ref. 97, the formation of the heart which 740a.] appears almost immediately after the “After this, as said already, the blood. internal parts come into being before And so the argument continues. In the external. The greater become visible the latter part of the seventeenth and before the less, even if some of them do throughout the eighteenth centuries come into being before them. First the preformation doctrine enthralled the parts above the hypozoma are some of the greatest minds and the differentiated and are superior in size; problem of the primacy of the parts naturally lost its importance. Not until but that it can be observed from very the middle of the nineteenth century, early stages of the egg in the ovary; and then only through the combined that it is, in fact, “the most important labors of Wolff, Pander, von Baer, part of the whole egg, and that for Reichert, Rathke, Schwann, Bischoff, whose sake all the others exist; it is Remak, KoIIiker and others were the that, in a word, from which the chick early stages of development properly takes its rise.” (Ref. 112, p. 215.) interpreted. Although not mentioned by Aldro- 19. Coiter probably means an egg opened vandus or Fabricius the circles sur after a few hours of incubation, very rounding the area pellucida referred to likely not more than twelve. Here we by Coiter are often mentioned in have the first published description of seventeenth century descriptions of the the blastoderm. The “white circle” blastoderm, but the number described probably refers to the area pellucida; by different observers varies. Under the “point or disc” in its middle may favorable conditions, it is possible that refer either to the nucleus of Pander or, four such circles or areas might be seen more probably, to the rather diffuse in the early blastoderm, namely (1) thickening which marks the appearance the area vitellina interna and (2) the of the primitive streak. The two circles area vitellina externa and, as parts of (see note 20) probably are the area the latter, (3) the germ wall and (4) the vitellina interna and externa. ErdI margin of overgrowth. Somewhat later, fRef. 106, Bd. 1, Taf. 2, Fig. 1.) has the mesodermal area or area vasculosa a beautiful figure of the blastoderm might be seen. It is, however, very hard after ten hours of incubation illus­ to interpret early observations in the trating these structures. Coiter’s des­ light of modern knowledge. cription might well be applied to it. Parisanus is said by Harvey (Ref. The germinal disc or cicatricula of the 112, p. 233) to have described “a honey­ unincubated egg is not mentioned by colored, a white, a gray, and another Coiter, although it is rather vaguely white circle.” These might easily refer referred to by Aristotle when he says to the four areas just mentioned. “the principle of the male is separated According to Harvey (Ref. 112, p. off in eggs at the point where the egg is 230), “On the second day of incuba­ attached to the uterus” (meaning tbe tion . . . the cicatricula in question is ovary). It was called the cicatricula found to have enlarged to the dimen­ by Fabricius, who regarded it as a sort sions of a pea or lentil, and is divided of scar, representing the point of attach­ into circles, such as might be drawn ment of the egg to the peduncle (Ref. with a pair of compasses, having an 107). According to Fabricius it plays extremely minute point for their cen­ no role in the formation of the ter.” And again, “The second day gone chick. by, the circles of the cicatricula . . . Parisanus,124 whose treatise I have have become larger and more con­ been unable to examine because of its spicuous . . . By these rings the cica­ extreme rarity, is said to have observed tricula is indistinctly divided into two, the cicatrix and stated that the chick occasionally three regions, which are arises from it. He interprets it as the frequently of different colors ...” semen of the cock. (See Harvey,112 (Ref. 112, p. 232.) p. 227.) Harvey, however, was mistaken in Harvey refutes Parisanus as to the his interpretation of the relation of the seminal nature of the cicatrix and is chick to the blastoderm. According to the first to have recognized clearly its him the chick is formed in the sub- very early appearance and traced its germinal fluid (colliquament) which he history systematically. He correctly confused with the amniotic fluid. The states that it is not a scar marking the blastoderm, according to Harvey, rep­ site where the peduncle has been resents the amnion. (Ref. 112, p. severed and not the semen of the cock 233ff.) The descriptions of Highmore,113 Langly120 and Steno134 are also of inter­ as the name treadle (galladura, I tai.) est in this connection but limitations testifies. They were described by Aris­ of space will not permit citation. totle (Ref. 98, 560a, 25-30) who very 20. This is a difficult sentence to interpret. properly says they contribute in no Coiter says, “Ex circulo fluebant duo way to generation. He, of course, does germini, quorum alter crassior et Ion- not regard them as of seminal origin. gior altero existebat.” The form germini, Albertus Magnus (Ref. 95, lib. 6, tr. 1, regularly the dative singular of germen, cap. 2:13) states that the semen of the makes no sense, and from the context a male may be found in the egg as a vis­ nominative plural should, probably, cid, white substance extending through follow duo. I have assumed that germini the albumen to the yolk. He is appar­ is a misprint for either germina or ently describing the chalazae. Aldro­ gemini. In the first case the rendering vandus makes the same error: “This would be: “From the circle two [the chalaza} Aristotle thinks con­ offshoots flowed”; in the second, tributes nothing to generation, which “From the circle two twin (circles) seems to gainsay the truth, since eggs flowed,” or more freely, “two identical which lack it are all infertile; I there­ or similar circles.” I believe the latter fore think that it is the same as the interpretation is correct. It is interest­ sperm.” (Ref. 96, vol. 2, p. 209). ing to note that Schoock, in his “Dis- Fabricius denies that the chalazae sertatio de ovo et pullo,” 1643, para­ represent the semen of the cock (Ref. phrases this sentence of Coiter’s as 107, pp. 30, 34) and states that they follows: “Ex circulo dicto, duo alii represent the material from which the fluunt,” i.e., “From the said circle, chick is formed because there are only two others flow.” three things in the egg from which the 21. That is after about twenty-four hours chick could be formed, namely the of incubation. Cf. Aldrovandus, who be­ yolk, the albumen and the chalazae; gins his description of the development since the albumen and yolk serve as of the chick on the second day: “On nutriment, therefore the chalazae must the second day of incubation I observed form the chick. He recognizes, how­ that the yolk was brought toward the ever, that there are a number of objec­ sharp end [0/ tbe egg], altered in some tions to this conclusion, among which way and rather white in the middle, a are: (1) the chalazae seem to function circumstance, which Aristotle particu­ as ligaments; (2) they are found in both larly does not mention.” ends of the egg; (3) the chalaza found 22. The external shell membrane. in the obtuse part of the egg where he 23. The inner shell membrane. believed the chick to be formed is too 24. Aristotle (Ref. 98, 561a). Another small to provide enough material for point about which there was much con­ the chick. troversy. Harvey says, for example: Fabricius is refuted by Harvey, who “Aldrovandus, adopting an error akin points out that the chalazae “are mere to that of Aristotle, says besides, that appendages of the albumen and vitel- the yolk rises during the first days of lus . . . the extremities of certain mem­ incubation into the sharp end of the egg, branes, twisted and knotted; they are a proposition which no eyes but those produced in the same way as a rope is of the blind would assent to ... ” formed by the contortion of its com­ (Ref. 112, p. 227.) In the early part of ponent filaments.” (Ref. 112, p. 329.) incubation the yolk would naturally He interprets them as ligaments serv­ rise to whatever end of the egg hap­ ing to stabilize the yolk. He also, quite pened to be uppermost when opening correctly, holds that the cicatricula, the egg. from which the chick arises, lies 25. The primitive streak? midway between the chalazae, and 26. Coiter refers to the chalazae. These that the nodes of the latter bear no were as he says, generally regarded as resemblance to the fetus as Fabricius being formed by the semen of the cock maintains. It is interesting to note that Wolff tained a quantity of perfectly bright (Ref. 142, p. 87) was almost misled by and transparent fluid, even purer than the chalazae. He reports that he at first any crystalline humour; which if it be sought for the embryo in them. viewed transversely and against the We now know that the chalazae are light, the whole spot will rather appear not properly membranes but simply to be situated in the albumen than the denser, spirally-wound portion of sunk into the membrane of the yolk as the albumen. before: it presents itself as a portion 27. After about forty-eight hours of incu­ of the albumen dissolved and clarified, bation. and included within a most delicate 28. Coiter refers to no “sanguineous tunica propria. Hence I entitle this point” on the second day; he probably fluid the oculum seu colliquamentum thought that the “point” (probably album; it is as if a portion of the the primitive streak) described on the albumen, . . . formed a more spiritous second day became the “sanguineous and better digested fluid, separated point” on the third. from the rest of the albumen by a It is hard to understand what he tunica propria, and situated between means by “formerly found in the the two masses of liquid, the yolk and yolk, but now rather found in the the albumen.” (Ref. 112, p. 232.) albumen.” Harvey’s colliquamentum refers no Harvey comments as follows: doubt to the fluid which collects in the “Volcher Coiter has these words: subgerminal cavity and causes the ‘the sanguineous point or globule, which blastoderm to become somewhat sepa­ was formerly found in the yolk, is now rated from the yolk. According to observed more in the albumen, and Harvey the embryo is formed in the pulsates distinctly.’ He says errone­ colliquament and is invested by the ously ‘formerly found in the yolk,’ for tunica propria, by which the blastoderm the point discovered in the vitellus is is to be understood. white, and does not pulsate; nor does Coiter probably makes a similar the sanguineous point or globe appear error, regarding the blastoderm at first to pulsate at the end of the second day as a part of the yolk and later, interpret­ of incubation. But the point which we ing the subgerminal fluid as albumen, have indicated in the middle of the thinks of the “sanguineous point” as circle, and as constituting its center in lying in it. This interpretation is connection with the vitellus, disappears supported by Coiter’s description of before that point which was charac­ two albuminous substances on the terized by Aristotle as palpitating, can ninth day. One portion is described be discerned; or, as I conceive, having as transparent and as containing the turned red, begins to pulsate. For both chick. points are situated in the center of the 29. Compare Aristotle: “with the com­ resolved fluid, and near the root of the mon hen after three days and three veins which thence arise; but they are nights there is the first indication of the never seen simultaneously: in the place embryo; . . . Meanwhile the yolk of the white point there appears a red comes into being, rising towards the and palpitating point. That portion of sharp end, where the primal element of Coiter’s sentence, however, where he the egg is situated, and where the egg says: ‘the punctus saliens [Coiter says gets hatched; and the heart appears sanguineus] is now seen in the albumen like a speck of blood, in the white of the rather than in the yolk’ is perfectly egg. This point beats and moves as accurate.” (Ref. 112, p. 236.) though endowed with life, and from it The following passage from Harvey two vein-ducts with blood in them explains the foregoing and helps to trend in a convoluted course (as the shed light on the possible meaning of egg substance goes on growing, towards Coiter’s statement: “Within the circles each of the two circumjacent integu­ of the cicatricula, I say, there is con­ ments) ; and a membrane carrying bloody fibers now envelops the yolk, “And about this time [the twentieth leading off from the vein-ducts.” (Ref. day] is plain to be seen the membrane 98, 561a.) resembling an afterbirth [the allanto- Aristotle, therefore, believes that chorion] that comes next after the the heart begins to beat on the fourth outermost membrane of the shell, into day, i.e., after about seventy-two hours which membrane the one of the navel of incubation. Aldrovandus, like Coiter, strings [allantoic stalk and vessels] was describes the punctum saliens on the described as leading (and, by the way, third day (Ref. 96, vol. 2, p. 217), but the chick in its entirety is now within Harvey does not mention it until the it), and so also is the other membrane fourth as “a leaping point, of the resembling an afterbirth, namely that colour of blood, so small that at one surrounding the yolk [the yolk sac], moment, when it contracts, it almost into which the second navel string entirely escapes the eye, and again, [the yolk stalk and vitelline vessels] when it dilates, it shows like the smallest was described as leading ...” (Ref. spark of fire.” (Ref. 112, p. 235.) 98, 562a, cf. also 5616.) 30. The vitelline vessels. Aristotle therefore describes the 31. Coiter here refers to the yolk sac. following in the bird egg, namely the In order to understand Coiter’s allanto-chorion (or serosa), the amnion description of the fetal membranes, it and the yolk sac; the allantois and is necessary to know something of their chorion are not differentiated but history and the nomenclature used by collectively described as resembling an the ancients in describing them. In the afterbirth, probably because of their Hippocratic treatise “De natura pueri” vascularity. For a similar reason the (Ref. 114, t. 7, p. 497) the development yolk sac is described as resembling an of the fetal membranes is only vaguely afterbirth. The mammalian chorion described and the word chorion (xopwj') and amnion are clearly described by is apparently to be understood as Rufus of Ephesus (Ref. 127, p. 166) and applying to the entire afterbirth, but Soranus of Ephesus (Ref. 130, Kap. the amnion and, of course, the allantois 17, p. 40). The latter says that the and yolk sac are not mentioned. chorion is frequently called the after­ The amnion, according to Rufus of birth because it follows the embryo at Ephesus (Ref. 127, p. 166), was named birth. by Empedocles. The chorion, amnion and allantois, In Aristotle we find, among others, probably of some domesticated mam­ the following pertinent passages. “And mal, are clearly described by Galen first of all the animal develops within (Ref. no, t. 2, pp. 137-138). But the innermost envelope, and then he uses only the term xopcov in describ­ another membrane appears around the ing the afterbirth. (Ref. 117, p. 473; former one, which latter is for the most Ref. 109, vol. 5, p. 557.) part attached to the womb, but it is in The term secundae, or, less properly, part separated from it and contains secundinae is used by Celsus and Pliny fluid.” (Ref. 98, 586a, 25-30, cf. also to apply to the afterbirth and the Ref. 97, 746a.) secundinae are described by Avicenna In describing the membranes of the as consisting of three panniculae: the chick, he says “A membrane [the chorion, amnion and allantois (Ref. allanto-chorion] with a liquid resembling 117, p. 472). The word long continued serum envelops the entire structure. to be used as applied to all the mem­ Then comes another membrane [the branes and the placenta. From it is, of amnion] right around the embryo, as course, derived the English secundines, has been described, separating it off applied to all the membranes of the against the liquid. Underneath this afterbirth. comes the yolk, enveloped in another The term secundina is usually used membrane [the yolk sac] ...” (Ref. by Coiter to apply to the allanto- 98, 5616.) chorion of the chick but by transference is also used for the yolk sac, since it, 49. The amnion. too, is vascular. This is the case in the 50. Coiter probably removed the heart present instance. We have also noted and observed its beating after removal. (vide supra) that Aristotle refers to the In his “Observationum anatomicarum yolk sac as resembling an afterbirth. chirurgicarumque miscellanea,” etc., It should, of course, be appreciated he states that he removed the hearts that the human allantois and the of cats, vipers and lizards and describes mammalian yolk sac were not correctly their motion after excision. described and interpreted until rela­ 51. That is, the amniotic fluid contained tively recent times, but a discussion of in the amnion and the albumen in the this latter point would not be pertinent albumen sac. (See Lillie,121 p. 224.) here. 52. The amniotic fluid. 32. Outer shell membrane. 53. The allanto-chorion. 33. Inner shell membrane. 54. Aristotle (Ref. 98, 561a, 25-30). 34. The embryo at this time lies on its 55. The nictitating membrane, of course. left side. Due to the rapid forward 56. According to Galen the liver and growth and bending of the brain it lies other viscera are formed from blood, largely above and to the right of the the whitish, elastic structures like heart. (See Erdl’s106 Fig. 15, Taf. 2 and membranes, nerves, vessels and the Lillie’s121 Fig. 121.) Early on the fourth brain arise from semen (Ref. 102, p. 49). day (i.e., after about seventy-two hours Cf. Galen (Ref. 109, vol. 4, p. 551): of incubation), the head would probably “Omnia enim, quae sunt carnosi lie some distance above the origin of generis, ex sanguine generata sunt; the vitelline arteries (cf. Lillie’s Fig. 99), membranosa vero omnia ex semine so that Coiter’s statement that the ortum habent.” brain vesicles were found “on one Also (Ref. 109, vol. 4, p. 658) side” and the vitelline vessels on “the “Quaecunque tamen albae et exangues other side” may possibly be explained partes sunt, non ex ipso sanguine, ut on the basis of this fact. jecinoris substantia, procreari possunt.” 35. The vitelline vessels. See also Harvey (Ref. 112, p. 255): 36. The allanto-chorion together with “Meantime we may be permitted to the inner shell membrane. smile at that factitious division of the 37. The eyes. parts into spermatic and sanguineous; 38. The brain vesicles. as if any part were produced im­ 39. It is not clear to what this refers. mediately from the seminal fluid and 40. The brain. all did not spring from the same semen.” 41. The text reads: “Sexto die praeter 57. The vitelline artery and vein. reliqua, quae omnia fuere maiora, 58. The amniotic fluid. vidimus ab obtusiore parte post mem­ 59. The external shell membrane. branarum sive pellicularum primo 60. The internal shell membrane. albumen ...” Since membranarum 61. The allanto-chorion. sive pellicularum can hardly be 62. The amnion. governed by post, I have assumed that 63. The egg tooth, which, however, is there is some omission here. placed on the upper bill only. Aldro­ 42. Coiter confuses the albumen and vandus probably discovered it, although amniotic fluid. See note 28. his description was not published until 43. Lactantius (Ref. 119, p. 78). See after Coiter’s. In his description of the note 18. eleventh day of development Aldro­ 44. Here the allanto-chorion. vandus says: “ . . . there was some­ 45. Not really the albumen, but the thing white, cartilaginous and rather amniotic fluid. See note 28. hard on the end of the upper beak, 46. The allantoic and vitelline vessels. which was more conspicuous on the 47. The allanto-chorion. thirteenth day. It was moreover round 48. The yolk sac becomes somewhat bi­ and not dissimilar to a millet-seed. Iobed. Nature, the very wise parent of things seems to have formed it there to pre­ may really be the allantoic and vitel­ vent the venules, small membranes or line arteries, which actually join the any other small structures in its bill dorsal aorta. The vein described as from being perforated. Women say entering the vena cava is probably the that chicks when born cannot take vitelline vein which actually joins the food unless it is first removed.” (Ref. hepatic portal. Baudrimont and St. 96, vol. 2, p. 218.) Ange (Ref. 101, Pl. vi, Fig. 3) give an 64. The albumen sac. excellent figure of the circulation in a 65. The yolk sac. Cf. Aristotle (Ref. 98, fifteen day chick. A study of it shows 561a, ff.). how easily Coiter might have made the 66. The allantoic vein. mistakes he did. Compare Harvey’s 67. The allanto-chorion. statement (Ref. 112, p. 260). 68. The vitelline vessels, probably the 80. The yolk stalk. It was described by artery and vein. Aristotle (Ref. 98, 562a 5; Ref. 97, 69. Very likely the intestines, rather than 7536 20), but after Coiter, not de­ arteries. See Coiter’s description of the scribed by Aldrovandus, Fabricius or sixteen-day chick. Harvey, although some of Fabricius’ 70. The allanto-chorion. figures apparently show it. It was re­ 71. The allantoic vein. discovered by Steno132 in 1664 and 72. Coiter uses the term chorion only described also by Needham in 1667 twice. He usually calls the allanto- (Ref. 123, pp. 94-97) who states that he chorion the secundine. had already observed it in 1654 and had 73. The amnion. demonstrated it to several friends. (See 74. Cf. Lillie,121 p. 223. See note 89. Steno,131 vol. 1, p. 263.) 75. The yolk sac, which, however, is 81. The yolk stalk is usually thought of attached to the gut by way of the yolk as a single passageway from the yolk stalk and does not arise from the um­ sac to the intestines. Steno132 and bilicus or skin of the chick. Needham123 also speak of passages but 76. In the chick the intestinal loop pro­ it is possible that all these observers jects into the umbilical cord after mistook blood vessels for communica­ about the fifth day. The intestines are tions between the yolk sac and intes­ gradually retracted into the abdominal tines. Coiter speaks once of “an out­ cavity during the seventeenth and growth from the intestines to the yolk,” eighteenth days. and again of a canal prolonged from 77. The allantoic fluid. the intestines. The text here, however, 78. The amniotic fluid. clearly calls for passages. 79. One would probably find five blood 82. Aristotle (Ref. 98, 562a 5 ff.). vessels in the umbilical cord of the 83. The amnion, which expands down chick at this time: (a) the left allantoic over the yolk sac. vein, (b) the left allantoic artery, (c) 84. The yolk sac. the smaller right allantoic artery, (d) 85. No doubt the amnion which has ex­ the vitelline vein, (e) the vitelline panded so as to cover the yolk sac. Cf. artery. The fact that Coiter found but Lillie (Ref. 121, p. 230). four vessels may, possibly, be due to 86. This is actually the case, but the the fact that he overlooked the small allantois also plays a role. See Lillie right allantoic artery which, however, (Ref. 121, p. 230). may actually disappear before this 87. The yolk sac. time. The identification of the vessels 88. Albertus Magnus: (Ref. 95, Lib. vi, mentioned by Coiter is difficult, but if tract 1, cap. 4: 37.) the foregoing assumption is correct it is possible that he mistook the allan­ 89. Probably the (1) inner and (2) outer toic vein for an artery, although he shell membranes, (3) the inner layer later (twentieth day) says that it of the allantois fused with the amnion pulsated. The two so-called veins de­ and (4) the outer layer of the allantois scribed as entering the mesenteric veins fused with the chorion. The latter two are fused in the region of the so-called 105. Columella, L. De re rustica. Ed. J. G. yolk sac umbilicus. 4 Schneider. Lipsiae, 1794. 90. The inner layer of the allantois and 106. Erdl, M. P. Die Entwickelung des the allantochorion. Menschen und des Huhnchens im 91. Coiter is inconsistent. He formerly Eie. Bd. I, Theil I. Entwickelung der described only one artery among the Leibesform des Huhnchens. Leipzig, four vessels which he found in the 1845. umbilicus (See note 79). A few lines 107. Fabricius ab Aquapendente, H. De further on, he again speaks of “the formatione ovi et pulli. Patavii, 1621. umbilical artery which was mentioned 108. Fallopius, G. Observationes an- on the seventeenth day ...” atomicae. Venetiis, apud M. A. 92. The yolk stalk. See note 81. Ulmum, 1561. 93. See note 79. 109. Galen, CI. Opera omnia. Ed. curavit 94. Possibly the mesenteric and the C. G. Kuhn. T. 1-20. Lipsiae, 1821- vitelline veins. 33- no. ------. Oeuvres anatomiques, physi­ References ologiques et medicales de Galen. 95. Albertus Magnus. De animalibus Trad, par Ch. Daremberg. 2 t. Iibri xxvi. Nach der Kolner Urschrift. Paris, 1854-56. Ed. H. Stadler. In: Beitr. z. Gescb. d. hi. de Graaf, R. De mulierum organis Phil. d. Mittelalters, Bd. 15-16, Miin- generationi inservientibus. Lugd. ster, 1916, 1921. Batav., 1672. 96. Aldrovandus, Ulysses. Ornitho- 112. Harvey, W. The Works of William Iogiae. Tomus alter. Bononiae, 1600. Harvey, m.d. Trans, from the Latin 97. Aristotle. De generatione animalium. by Robert Willis. London, 1847. Trans, by Arthur Platt. Oxford, 113. Highmore, N. The History of Genera­ 1912. tion. London, 1651. 98. ------. Historia animalium. Trans. 114. Hippocrates. Oeuvres completes d’Hip­ by D’Arcy W. Thompson. Oxford, pocrate. Trad, par E. Littre. 10 t. 1910. Paris, 1839-1861. 99. Avicenna (Ali Ibn Sina). Trois traites 115. His, W. Die theorien der geschlecht- d’anatomie arabes. Trad, de P. de Iichen Zeugung. Arch. f. Antbrop., Koning. Leide, 1903. 4: 197-220; 317-332, 1870;5:69-111, 100. von Baer, K. E. De ovi mammalium 1871. et hominis genesi. Lipsiae, 1827. 116. van Horne, J. Prodromus observa- 101. Baudrimont, A., and St.-Ange, G. J. tionum suarum circa partes genitales Martin. Recherches anatomiques et in utroque sexu. Leidae, 1668. physiologiques sur Ie developpement 117. Hyrtl, J. Onomatologica anatomica. du foetus, et particuli&rement sur Wien, 1880. revolution embryonnaire des oiseaux 118. Kerkring, T. Anthropogeniae ichno- et des batraciens. Mem. sav. etrang., graphia. Amstelodami, 1671. 11:469-692, 1851. 119. Lactantius (L. Caelius Lactantius 102. Bloch, B. Die geschichtlichen Grund- Firmianus). On the Workmanship lagen der Embryologie bis auf Harvey. of God. In: The Works of Lactantius. Nova Acta. Abb. d. Kais. Leop.- Trans, by William Fletcher, vol. 2. Carol. Deutsch. Akad. d. Naturf., Edinburgh, 1871. 82: 215-334, 1904. 120. Langly, W. Observations quaedam de 103. Censorinus. Livre de Censorinus sur generatione animalium. De genera­ Ie jour natal. Trad, par M. J. Man­ tione pulli ex ovo gallinaceo singulis geart. Paris, 1843. (De die natali, post incubationem diebus a nobis Latin and French text.) inspecto. In: Schrader, J. Observa­ 104. Choulant, L. History and Bibli­ tiones et Historiae. Amstelodami, ography of Anatomic Illustration. 1674. Trans, and ed. by Mortimer Frank. 121. Lillie, F. R. The Development of the Chicago, 1920. Chick. N. Y., 1919. 122. Malpighi, M. Opera Omnia . . . tomis et glandulis observationum specimen. duobus comprehensa. Londini, 1686. Hafniae, 1664. 123. Needham, W. Disquisitio anatomica de 133. ------Elementorum myologiae speci­ formato foetu. Londini, 1667. men. Florentiae, 1667. 124. Parisanus, Ae. Nobilium exercita- 134. ------In ovo et pullo observationes. tionum libri duodecim. Venetiis, 1621. Acta Med. et Phil. Hafniensia, 2: 125. Plinius secundus, C. The Histone of 81-92, 1673. the World. Trans, into English by 135. ------Observationes anatomicae Philemon Holland. 2 vols. London, spectantes ova viviparorum. Acta 1601. Med. et Phil. Hafniensia, 2: 210-218, 126. Plutarch. Plutarch’s Morals. Trans. 1673. from the Greek by several hands. 136. ------Ova viviparorum spectantes Corr, and rev. by W. W. Goodwin. observationes. Acta Med. et Phil. Vol. 4. Boston, 1878. Hafniensia, 2: 219-232, 1673. 127. Rufus of Ephesus. Oeuvres. Trad, par 137. Vesalius, A. Opera Omnia anatomica Ch. Daremberg. Cont. par Ch. E. et chirurgica cura H. Boerhaave et Ruelle. Paris, 1879. B. S. Albini. Lugd. Batav., 1725. 128. Schoock, M. Dissertatio de ovo et pullo. 138. Wachtler, Io. De Alcmaeone Cro- Ultra jecti, 1643. toniata. Lipsiae, 1896. 129. Singer, C. The Evolution of Anatomy. 139. Weindler, F. Geschichte der gynakolo- N. Y., 1926. gisch-anatomischen Abbildung. Dres­ 130. Soranus of Ephesus. Die Gynakologie den, 1908. des Soranus von Ephesus. Uber- 140. Wharton, T. Adenographia. Londini, setzt von H. Luneberg. Miinchen, 1656. 1894. 141. Will, G. A. Nurnbergisches Gelehrten- 131. Steno, N. Opera Philosophica. Ed. Lexicon. Niirnberg, 1755. by V. Maar. 2 vols. Copenhagen, 142. Wolff, C. F. Uber die Bildung des 1910. Darmkanals im bebriiteten Hiihn- 132. ------De vitelli in intestina pulli chen. Ubersetzt von J. F. Meckel. transitu epistola. In: De musculis Halle, 1812.