ON GENERATION. 495 



this time present themselves as ample sacs filled with blood, 

 continuing to pulsate for some short time after the ventricles 

 themselves had left oif contracting. 



The internal organs, all of which had lately become perfect, 

 were now larger and more conspicuous. The skull was partly 

 cartilaginous, partly osseous. The hooves were yellowish, flex- 

 ible, and soft, resembling those of the adult animal softened in 

 hot water. The uterine caruncles, of great magnitude and like 

 immense fungi, extended over the whole cavity of the uterus, 

 and plainly performed the office of placentae, for numerous and 

 ample branches of the umbilical vessels penetrated their sub- 

 stance there to imbibe nutritive matter for the growth of the 

 embryo. As in the foetus after birth, the chyle is now carried 

 by the mesenteric veins to the porta of the liver. 



Where there is a single foetus the umbilical vessels are dis- 

 tributed to the whole of the carunculse, both those of the horn 

 where the foetus is lodged and those of the opposite horn; where 

 there is a pair of embryos formed, the umbilical vessels of each 

 only extend to the caruncles of the horn appropriated to it. 



The smaller umbilical veins in tending towards the foetus, 

 form larger and larger trunks by coalescing, until at length 

 two great canals are formed, which in conjunction pour their 

 blood into the vena cava and vena portee. But the umbilical 

 arteries, which arise from the division of the descending aorta, 

 form two trunks of small size, not remarkable save for their 

 pulse : proceeding to the boundary of the conception, in other 

 words, to the conjunction of the placenta or carunculse with 

 the ramifications of the umbilical veins, they first divide into 

 numerous capillary twigs, and then are lost in others that are 

 invisible. 



As the extremities of the umbilical veins within the uterus 

 terminate in the caruncles, so the uterine vessels on the out- 

 side, which are large and numerous, and bring the blood from the 

 mother towards the uterus, by means of the vessels of the sus- 

 pensory ligaments, terminate externally on the caruncles. It 

 is to be noted, also, that the internal vessels are almost all veins ; 

 the external vessels, again, are in many instances branches of 

 arteries. In the placenta of the woman, if it be carefully ex- 

 amined immediately after delivery, a much larger number of 

 arteries than of veins, and these of larger size, will be found 



