Meyer - The Hunters in Embryology 2

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See also William Hunter

Arthur William Meyer (1873 – 1966)
Arthur William Meyer (1873 – 1966)
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The Hunters in Embryology II

By A. W. Meyer, M.D.

Stanford University

Part I of this paper was printed in the November issue. page 420.
Fig.1. The Reynolds portrait of William Hunter, after Peachey, 1924.

IN addition to many fine representations of the pregnant uterus, this costly volume of William Hunter’s contains drawings of dissections of the latter, and representations of the ovaries and of placentae injected with colored wax from the uterine and umbilical vessels. Although it was the dissection and study of a doubly injected uterus, with the injected fetus in loco, that convinced John of the independence of the maternal and fetal circulations, the relationship of these circulations is left without comment in Wi11iam’s famous treatise. It is true that William referred to “RR” as “Veins emerging from the substance of the placenta and broken through at its surface, where they were passing into the womb” in connection with Plate 19, and that he said in connection with figure II, Plate 24: “Most of the blue wax, which was first injected by the veins of the womb, was driven on towards the internal surface; and the red wax, which was afterwards injected by the arteries, was lodged principally in the outer parts; but the two colours were, more or less, blended through the whole.” In one of the legends accompanying Plate 5, he spoke of “ee” as “injected veins, of a flattened figure with numerous anastomoses, passing from the womb to the placenta in a very slanting direction.” “LL” of figure 1 of Plate 24 is of “The placenta, adhering to the womb. None of the wax, injected into the vessels of the womb, had passed into the branches of those vessels which compose the navelstring; . . . but the cells, or interstices in the spungy part of the placenta, were universally loaded with wax, either the blue, which was injected into the veins of the womb, or the red, which was thrown into the arteries.” In connection with “BBB,” figure 1, Plate 29, he said: “The round surface, enclosed by that edge, is the outer surface of the placenta, which had adhered to the womb. In separating those two parts, many arteries and veins were torn through, one part of each remaining with the womb, and the other with the placenta.”

On the Independence of the Fetal and Maternal Circulations

Although these words leave the crucial conclusion to the insight and inference of the reader, it may be recalled that William said that his “discovery” of the independence of the fetal and maternal circulations had been acknowledged by Haller thirteen or fourteen years before the disagreement with his brother john in 1780, in Haller’s Elementa physiologiw corporis humani, Vol. 8, p. 220, which appeared in 1766. However, instead of having credited William with the discovery, Haller[1] merely gave a brief summary of William’s ideas in an addendum, retaining the contrary idea in the text and saying that Hunter’s ideas regarding the decidua have been “partly corrected and partly confirmed.” According to Haller’s statement in this addendum, William believed that a liquid injected into the vessels of the uterus “pours into every cellular part of the placenta, and from these cells returns into the broader veins of the uterus. None of it passes into the branches of the umbilical vessels. When the umbilical artery is filled with a colored liquid, while the placenta still adheres to the uterus, the branches of the umbilical arteries and veins are all completely and readily filled ; yet nothing passes into the vessels of the uterus, unless the liquid has poured into the cells of the placenta.” Haller hence merely stated that William believed that the two circulations were independent without characterizing the idea as a discovery. Since this was written in connection with a historical summary of the idea, it is not without significance.

Teacher[2] (1900) concluded that “. . . it is unreasonable to suppose that they [the injections] were figured then [17 50], yet only understood in 1754.” (p. lvi.) But it seems equally strange that William should have remained silent in 1774 in regard to what he said, in 1780, he so firmly believed and thought he had discovered in 1754. I do not know upon what grounds Teacher" (1899) stated that William’s conclusion regarding the distinctness of the maternal and fetal circulations “was, as Hunter was aware, strictly speaking, not a new discovery” (p. 32), but if justified, it robs William of his claim and reveals him in disparaging light. It may well be true, as Teacher held, that William Hunter presented the anatomical proof that the two circulations do not mingle, yet the real question is not whether he presented this proof, but whether he fully accepted it for man, before John, and that does not seem to have been the case. This point is referred to by an anonymous auditor“ of William’s lectures who recorded him as saying that

These appearances I first saw in a cat that was pregnant which I injected from the uterine vessels, after which I injected by the navel string. The injection was distinct, I afterwards saw the same in a bitch. These discoveries were early in life, and taught me to believe that the same course of things existed in the human species, though I could not demonstrate it, not having had an opportunity to inject a pregnant uterus; but soon after I did meet an opportunity, & the appearances staggered me. For after injection of the parts, I found the uterine injection filled up a great part of the placenta &c. which on examination proved to be spongy & cellular. (p. 82.)

Hunter no doubt was “staggered,” as well he might have been, because the injections of pregnant human uteri, instead of being unequivocal as in the cat and dog, were confused and seemed to controvert the conclusion reached from injections of the carnivora mentioned. However, according to Needhamf‘ “His [William’s] injections left no shadow of doubt about the matter, and the way was clearly opened up for the study of the properties of the capillary endothelial membranes separating the bloods . . .” (p. 201.) Since, as stated above, William said that Haller" credited him with the “discovery” of the independence of the fetal and maternal circulations, in 1766, it seems all the stranger that this idea was not given explicit expression in the Gravid Uterus, which appeared eight years later. It also is noteworthy that Haller did not adopt William’s idea in the third edition[3] of his Primce Line‘, in 1767, but maintained the idea expressed by him in the edition[4] of 1751 and found even in the German edition[5] of 1788 and the English edition[6] of 1801, in which one reads as follows: “This communication of fluids between the uterus and placenta, seems to be demonstrated . . . lastly, from the passage of water, quicksilver, tallow, or wax, from the uterine arteries of the mother into the vessels of the placenta, as observed, and lately confirmed by eminent anatomists.” (pp. 437-438, Section 891.) Two eminent anatomists who thought that they had proven this, according to Fasbender, were Cowper (Bidloo’s Anatomy, given out by Cowper at Oxford in 1697, in his own name) and Noortwyk (Uteri humani gravidi anatomia et historia, Lugd. Bat., 1743).

German edition Alexander Monro, Sr., and his sons, Donald and Alexander, are credited with having done much, experimentally and otherwise, to establish the correct view regarding the relations between the maternal and fetal circulations. Roederer (1725-1763) is likewise given credit for having done this and there can be no doubt regarding Monro, Sr., who wrote:[7] “ . . . I cannot be more certain of anything than that there is no anastomosis or continuity of these vessels in cows.” (p. 388.) He then quoted from Vieussens (Dissert. de Structura et Usu Uteri, &c., § 56):

“And again, ‘The effusion of blood at birth, without doubt was also the cause why several old anatomists, who were little acquainted with the natural oeconomy of the human body, yea and Mr. Mery, believed that the arteries of the womb directly opened into the veins of the placenta, and that the arteries of the placenta opened into the veins of the womb; from which they concluded, that the mother’s blood circulated into the body of the foetus, and that the blood of the foetus passed into the mother’s body. But the falsity of this opinion, which was refuted by many anatomists of the last century, who were not only skillful dissectors, but very learned natural philosophers, shall be most evidently demonstrated from what I am to say, when I explain the internal structure and the use of the placenta; so that the abettors of it will readily reject it.’ ” (pp. 390-391.)

It is true that Monro also declared that “The smaller share by far of the blood sent out by the umbilical arteries is returned to the uterus, most of it being poured into the umbilical vein by anastomosing canals. This may be seen by injecting liquors into the umbilical arteries of any creature.” (p. 392.) But by this he merely allowed for the return of some of the plasma by the “absorbents” (lymphatics) which he believed existed in the placenta. Monro also believed that the maternal and fetal circulations communicated with each other by means of invisible pores too small for the passage of blood cells. This view was in entire harmony with the prevailing view regarding absorption from the intestine to which Monro, in fact, referred.

As Cole said :

In the description of his plates of the gravid uterus, published posthumously in 1794, William Hunter states that he first injected the vessels of the foetal placenta from the navel string in 1743, but it was only when the plates were first issued in 1774 that this experiment was described. He says that he injected the placenta with wax of different colours—-the uterine arteries red and the veins blue, but none of the injection mass passed into the vessels of the navel string. In the 1794 publication further details are added. The placenta of man and quadrupeds, he remarks, is composed of two parts intimately blended-—a foetal element, which is the continuation of the umbilical vessels of the foetus, and a maternal, which is an “efflorescence of the internal part of the uterus” . . . When the second Monro and William Hunter were students, it was still believed that the maternal blood circulated through the foetus by the navel-string, and returned to the parental vessels, in spite of the positive demonstration to the contrary by the first Monro. Hunter’s belief in injection methods was deeply strengthened by his visit to Albinus in 1748, when the beautiful preparations of the Leyden Professor fired the imagination of the Scots anatomist. (pp. 333-334.)

(To be concluded)

Literature cited

  1. Haller, Albrecht von: Elements. physlologiae corporis humani. Tomus octavus. Fetus hominisque vita. Bernae, 1766.
  2. Teacher, John H.: William Hunter, anatomist: a. lecture with demonstration of preparations from the obstetrical series of the Hunterlan museum. Glasgow Medical Journal, 52:15-34, 1899.
  3. Haller, Albrecht von: Primse linse physiologise in usum preiectionum academicarum, ad editionem tertio acutam and emendatam expressze. Accedit rerum index. Edinburgi, 1767.
  4. Haller, Albrecht von: Primse linae physiologiae in usum praelectionum academicarum, auctae et emendatse. Gottingae, 1751.
  5. Haller, Albrecht von: Grundriss der Physiologic ftlr Vorlesungen. Nach der vierten lateinischen, mit den Verbesserungen und Zusatzen des Herrn Hotrath Wrisberg in Gtittingen, ver mehrten Ausgabe, von neuem iibersetzt und mit Anmerkungen yersehen durch I-Ierrn Hofrath Stimmerring in Mainz, mit einigen Anmerkungen begieltet und besorgt von P. F. Meckel. Berlin, 1788.
  6. Haller, Albrecht von: first lines of physiology. Translated from the third Latin edition. To which is added a translation of the index composed for the Edinburgh edition printed under the inspection of Dr. William Cullen. Edinburgh,
  7. Monro, Alexander: An essay on the nutrition of foetuses. pp. 369-444 in The Works of, Published by his son. Edinburgh, 1781. Also in Medical Essays and Observations, revised and published by a society in Edinburgh, 2:121-232, Edinburgh, 1734, and 3:267-275, 1735.

Cite this page: Hill, M.A. (2019, April 19) Embryology Meyer - The Hunters in Embryology 2. Retrieved from

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