292 O F T H E F O R MA T I O N 



to the fluids by heat ; and even this blood is 

 formed without the l.ody of the animal, the 

 %vhole fubftance of which confifls of a wliite 

 mucilage. 



The foetus, as well as the placenta, receive the 

 nourifliment that is neceffary for their expanfion 

 by a fpecies of abforption ; and they affimilate 

 the organic particles of the liquor in which they 

 fwim: For, it is an equal impropriety to fay that 

 the placenta nourifhes the animal, as that the a- 

 nimal nouriihes the placenta. If the placenta 

 nourifhes the foetus, the former would diminilli 

 in proportion to the growth of the latter, which 

 by no means happens ; for both augment toge- 

 ther. I have indeed obferved, that, in eggs, the 

 placenta at firft grows much more in proportion 

 than the foetus, and, confequently, it may nou- 

 rifh the animal; or, rather, it conveys nourifli- 

 ment to the chick by means of abforption . 



What we have faid concerning the chicken, 

 admits of an eafy application to the human foe- 

 tus, which is formed by the union of the orga- 

 nic particles of the tw^o fexes. The membranes 

 and placenta are produced by the fuperabundant 

 particles that enter not into the compofition of 

 the foetus, which is now inclofed in a double 

 membrane, containing alfo a quantity of fluid. 

 This fluid is at firfl: perhaps, nothing but a por- 

 tion of the feminal liquors of the father and mo- 

 ther ; and, as the foetus is not thrown out of the 

 uterus, it enjoys, from the moment of its forma- 



tionj 



