Volume 2

Manual of descriptive and pathological anatomy ... / Translated from the German into French, with additions and notes, by A.J.L. Jourdan ... and G. Breschet ... Translated from the French, with notes, by A.S. Doane, and others.

  • Meckel, J. F. (Johann Friedrich), 1781-1833
Date:
1839
Catalogue details

Licence: Public Domain Mark

Credit: Manual of descriptive and pathological anatomy ... / Translated from the German into French, with additions and notes, by A.J.L. Jourdan ... and G. Breschet ... Translated from the French, with notes, by A.S. Doane, and others. Source: Wellcome Collection.

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    4th. Because we can notconceive why the urinary sccrelion should Le the mast important function in the Iretus.* * * § 4th. Because the allantoid membrane is deficient in some mam- malia, and it is very improbable that the foetuses of some animals should secrete urine and others not.f 6th. Because it is very difficult in the nearly perfect foetns of the adult to pass air from the bladder into the allantoid membrane.;}; 7th. Because the fluid would not be excretory, since a cousiderable number of nmbilical veins (absorbents) are distributed in the enve- loping membrane.§ 8th. Because the fluid dififers from the urine.|| But all these arguments prove nothing against the old opinion, or in favour of that of the writers who adduce them. Ist. The existence of the allantoid membrane and its fluid without a foetus proves nothing, and that considered as such may be some- thing eise, or the foetus may not be deficient. 2nd. and 3rd. The sixe of the allantoid membrane and the quan- tity of its fluid during the early period of gestation, are explained very well by the more rapid progress of all the formations at this period, and because very probably the other excretions do not take place then, or at least but slightly. 4th. The size of the allantoid membrane does not prove that the urinary secretion is the most essential of all the fnnctions, but only that it replaces in great part all the other excretory Systems, from the simple reason that the products of the action of these latter had beeu in contract with the foetus during the whole of pregnancy. •5th. This fact is entirely incorrect, for the allantoid membrane is very constant. Farther its absence might possibly be compensated for in some way. 6th. In this case the same difficulty exists in passmg air from the allantoid membrane into the bladder,H while it is very easy during the early periods or gestation, as we have more thanonce proved. It follows then at most from this fact, that the quantity of urine secreted gradually diminishes, and collects in the bladder. 7th. This objection rests upon confounding the allantoid membrane with the chorion. The vessels do not belong to it, but to this latter; at least they do not absorb within it, but in the cavity of the Uterus.. 8lh. It does not follow, for several reasons, from the fact reported, .■ that the liquid was not urine. J We cannot consider the allantoid membrane as the formative mein- fl brane of the urinary and genital apparatus, or of the bladder,** for it * Id., ihid. t Id., ibid. t Oken, p. 5S. § Harvey. II Oken, p. 39. Ibid., p. 3ii. ** Joerg, p. 293.