ANIMALS. 873 



heart, that was hitherto exposed, is now covered 

 up within the body, by a very thin transparent 

 membrane ; and, at the same time, the umbilical 

 vessels, that unite the animal to the yolk, now 

 appear to come forth from the abdomen. After 

 the fifth and sixth days, the vessels of the brain 

 begin to be covered over ; the wing's and thighs 

 lengthen ; the belly is closed up, and tumid ; the 

 liver is seen within it, very distinctly, not yet 

 grown red, but of a very dusky white ; both the 

 ventricles of the heart are discerned, as if they 

 were two separate hearts, beating distinctly ; the 

 whole body of the animal is covered over ; and 

 the traces of the incipient feathers are already to 

 be seen. The seventh day, the head appears 

 very large ; the brain is covered entirely over ; 

 the bill begins to appear betwixt the eyes ; and 

 the wings, the thighs, and the legs, have acquir- 

 ed their perfect figure.* Hitherto, however, the 

 animal appears as if it had two bodies ; the yolk 

 is joined to it by the umbilical vessels that come 

 from the belly ; and is furnished with its vessels, 

 through which the blood circulates, as through 

 the rest of the body of the chicken, making a 

 bulk greater than that of the animal itself. But 

 towards the end of incubation, the umbilical ves- 

 sels shorten the yolk, and with it the intestines 

 are thrust up into the body of the chicken, by 

 the action of the muscles of the belly ; and the 

 two bodies are thus formed into one. During 

 this state, all the organs are found to perform 



* Holier. 



