THE PLACENTA. 565 



except at the period of birth ; at which time they become 

 loosened from their attachments and fall like ripe fruit. If 

 they are forcibly torn from the uterus, I have observed the 

 greater part of the blood that escapes to flow, not from the 

 " conception/' but from the uterus itself. 



Fabricius, 1 when discussing the mode of union between the 

 " fleshy substance" and the uterus, uses many arguments, but in 

 my opinion weak ones, to prove that the umbilical vessels anas- 

 tomose with those of the uterus: yet he seems chiefly to have 

 done so to countenance the old opinion once held almost by all ; 

 for he confesses that he can make no positive assertion on the 

 subject, " because the fleshy mass itself stands in the way of 

 any accurate investigation." Yet neither reason nor observa- 

 tion would lead us to believe that more anastomoses exist in 

 the uterus, than in the liver between the branches of the vena 

 porta3 and the cava ; or in the mamma, between the vessels which 

 transmit blood and those which carry milk. There may be, 

 indeed, at places a juxtaposition of vessels, and sometimes the 

 insertion of one into the coats of another ; but the perfect coa- 

 lition and union, described by Fabricius, never exist. Were 

 it so, the veins and arteries ought to be continuous; for the 

 vessels which bring the blood from the mother into the uterus 

 and caruncula3 are arteries, whilst those which pass from the 

 uterus to the foetus are veins, as is readily apparent ; for they 

 carry blood from the placenta into the vena cava. 



Hence the opinion of Arantius seems to me to be the true one, 

 viz. that the orifices of the umbilical veins are in no way con- 

 tinuous with the uterine vessels. For there is a smaller num- 

 ber of vessels carrying blood to the uterus than there is of 

 veins returning it to the foetus ; and the greater part of the 

 roots of those terminate in the chorion. Yet Fabricius, either 

 from respect to the ancients, or through an envious feeling 

 towards Arantius, most pertinaciously holds to the old opinion. 



1 De Form. Feet. p. 122. 



