DIFFERENTSYSTEMS. 87 



eggs are white, and they turn yellower in pro- 

 portion as they increafe. 



Fiaving examined thofe yellow eggs imme- 

 diately after a communication with the male, he 

 could perceive no feniible difference ; he law 

 none of the male femen in any part of the eggs ; 

 He therefore concluded, that the whole eggs, 

 and even the ovarium itfelf, were rendered fer- 

 tile by a fubtile fpirit which iffues from the male 

 femen J and, he adds, that, in order to prevent 

 the efcape of this fecundating fpirit. Nature has 

 placed, at the external orifice of the vagina of 

 birds, a membranous valve which permits the 

 feminal fpirit to enter freely into the vagina, 

 but prevents its return. 



When an egg is detached from the common 

 pedicle, it gradually defcends, through a wind- 

 ing canal, into an inferior pare of the matrix. 

 This canal is tilled with a liquor very fimilar to 

 the white of an egg. It is here that tlie egg 

 receives Its white liquor, the membrane in which 

 it is inclofed, the two cords {cbalazae) that run 

 through the white, and join it to the yolk, and 

 the fliell which is fuddenly formed immediately 

 before exclufion. Thele cords, according to 

 our author, are the part of the egg which is im- 

 pregnated by the feminal fpirit of the male; and 

 it is here alfo that the rudiments of the foetus 

 nrft appear. The egg is not only the true ma- 

 trix, or the place where the chick is formed, but 

 the whole bufmefs of generation depends upon 



it. 



