ON GENERATION. 261 



servation, that the membrane of the colliquament which we have 

 said unites with the external investing membrane, and consti- 

 tutes the secundine or chorion, now includes the whole of the 

 vitellus in one, and becoming contracted, draws the vitellus along 

 with the intestines towards the chick, conjoins them with its 

 body, and incloses them as it were in a thick sac. Everything 

 that was previously extremely delicate and transparent, becomes 

 more opaque and fleshy as the sac contracts, which at length, like 

 a hernial tumour of the scrotum, includes and supports both the 

 intestines and the yelk ; contracting every day in a greater and 

 greater degree, it comes finally to constitute the abdomen of the 

 chick. You will find the yelk, about the eighteenth day, lying 

 [in its bag] among the intestines, the belly at large being lax; 

 yet are the parts not so firmly fixed but that the intestines (as in 

 the case of a scrotal hernia), along with the vitellus, can be 

 pushed up into the belly, or forced out of it as it were into a 

 pouch. I have occasionally seen the vitellus prolapsed in this 

 way from the abdominal cavity of a pigeon, which had been 

 prematurely excluded from the shell in the summer season. 



The chick at this epoch looks big-bellied and as if it were 

 affected with a hernia, as I have said. And now the colliqua- 

 ment, which was at first in large quantity, gradually grows 

 tui-bid, suffers change, and is consumed, so that the chick comes 

 to lie bent over the vitellus. At the same period, before the liver 

 assumes its sanguineous colour, and performs the business of 

 what is called the second concoction, the bile, which is com- 

 monly believed to be separated as an excretion by the power of 

 the liver, is seen of a green colour between the lobes of that 

 organ. In the cavity of the stomach there is a limpid fluid 

 contained, obviously of the same appearance and taste as the 

 colliquament in which the foetus swims ; this passing on by the 

 intestines, gradually changes its colour, and is converted into 

 chyle ; and finally in the lower portion of the bowels an excre- 

 mentitious matter is encountered, of the same character as that 

 which is met with in the lower intestines of chicks already ex- 

 cluded from the egg. When the chick is further advanced you 

 may even see this fluid concocted and coagulated; just as in those 

 animals that feed on milk, a coagulum is formed, which after- 

 wards separates into serum and firmer curd. 



