The vitality of the blood : proved by physiological experiment, and its application to veterinary pathology demonstrated / by J.S. Gamgee.

  • Gamgee, Sampson, 1828-1886.
Date:
[1849?]
Catalogue details

Licence: Public Domain Mark

Credit: The vitality of the blood : proved by physiological experiment, and its application to veterinary pathology demonstrated / by J.S. Gamgee. Source: Wellcome Collection.

Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.

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    entirely around the young animal; in ruminants it is bicornuated ; and in the solidungulata an albuminous deposit separates its vascular layer from the mucous. So soon as the Wollfian bodies and the kidneys appear, they are placed in direct communication with the allantoid sac, through the medium of the sinus uro-genitalis ; and by the closure of the visceral arches the allantois is divided into a superior small por- tion, the urinary bladder ; and a central canal, the urachus, leading into the inferior and larger compartment external to the body. [See Fig. 4, PL I.'] Throughout the earlier period of these changes the ovum is perfectly free in the uterine cavity ; but, concurrently with the growth of the embryo, the vessels supplying the uterus increase in caliber ; the coats of that viscus acquire a greater degree of thick- ness, and an exudation from the tubular follicles of its mucous membrane produces the decidua. This, in the genei'ality of mam- malia, consists of epithelial cells and bloodvessels united by an albuminous deposit, in which the villosities of the chorion shoot and grow, so as to form one common foetal covering, the placenta; which exists in all mammiferous animals, with the only exceptions of the marsupalia and the monotremata. It is a fact worthy of notice, that the villi of the chorion assume various modes of distribution in different classes of animals. In the pachydermata, the camel, and the lama, they stud the mem- brane throughout its whole extent; but in the cow, sheep, goat, and their congenera, those villi are collected into cotyledons at different parts of the chorion, corresponding to uterine cotyledons, where the foetal blood undergoes the necessary changes for its adaptation to the functions of nutrition and growth. Important changes in the early epoch of embryonic life have already been narrated ; and we have endeavoured to explain the process of cellular development, from the original cleaving of the yolk into two masses : we have likewise described the appearance of the true germ on the germinal membrane, which is produced by vesicular arrangement of the vitelline contents; and, finally, we have alluded to the foundation of the nervous system by a part of the embryo cells. The vascular apparatus in progress of development now remains to be considered ; and, since we have undoubted proof that the