A compendious system of midwifery : chiefly designed to facilitate the inquiries of those who may be pursuing this branch of study ... / by William P. Dewees.

  • Dewees, William P. (William Potts), 1768-1841.
Date:
1839
Catalogue details

Licence: Public Domain Mark

Credit: A compendious system of midwifery : chiefly designed to facilitate the inquiries of those who may be pursuing this branch of study ... / by William P. Dewees. Source: Wellcome Collection.

Provider: This material has been provided by the University of Massachusetts Medical School, Lamar Soutter Library, through the Medical Heritage Library. The original may be consulted at the Lamar Soutter Library at the University of Massachusetts Medical School.

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    ever, that this is rather a hasty, and uncandid denunciation; at least, as regards the exhalents, and perhaps the ]ym})hatics; as a useful purpose might be assigned for their existence, if we cannot imagine any utility in the presence of nerves in so insulated a membrane. It adheres very firmly to the pla- centa, and gives a covering to all its superficial vessels; it also accompanies the amnion, along thd whole extent of the cord. Its outer surface, very quickly after its escape from the ovarium is found to assume a cellular appearance, and presently, a flocculent one—it is this coat which furnishes from its exter- nal surface, the innumerable vessels by which it unites itself to the uterus by means of the decidua. When this union is effected, an interchange of offices takes place between the chorion and de- cidua; they reciprocally permit each other's vessels to repose themselves throughout their respective extents, by interlocking in such a manner, as to establish a firm union between them. The extremities of the vessels of the chorion penetrate the in- terstices offered by the vessels of the decidua; while those of the latter seek refuge in the meshes of the chorion.* The union of the chorion with the decidua is so strict, especially after the second month, as always to bring it with it, in cases of abortion. -181. These membranes enclose, besides the embryo and pla- * Velpeau denies tlie vascularity of these filamentous productions: we are far from being' satisfied that he is correct in making this denial. If we comprehend this author, the formation of tlie placenta is entirely independent of the decidua and chorion; a circumstance, to say the least, that wants proof. He says, It is generally thought that the down that covers the chorion is of a vascular nature; but as early as 1823,1 ventured to oppose this hypothesis. What proves that the filaments of the chorion are not vessels, is this, that they are to be seen before the blood vessels of the cord are recognisable. Besides, until tlie sixth week, every Jlock {filament) is at least as large as one of the umbilical vessels; so that, as there are only three of these, it is difficult for them to give birth to the others, which amount to several hundred. Now, we would ask any candid person, whe- ther this amounts to more than a negative proof of what he wishes to establish: for it is not essential, perhaps, to tlie existence of these filaments, that the um- bilical vessels be visible, as the chorion may have an independent power to form them. Besides, it is not absolutely necessary, for the formation of vessels pro- ceeding from it. We luivo sufliicient evidence of this in the division of the caro- tids, &c. Farther, these villosities are regularly spread over the whole of the pe- riphery of the ovule, and are independent of each other, while the cord and pla- centa are only connected with one point of this vesicle. M. Velpeau seems to forget that this kind of arrangement exists in the fully developed placenta; for the cord is inserted but at one point of this mass; and it would puzzle him to show that the whole composition of this important organ is not vascular; and that the area of ail this immense congeries of vessels, does not exceed the area of the vessels constituting the cord.