94 ' EXAMINATION OF 



On the fixth da^^, the parts of the head arc 

 more apparent. We diftinguifh the coats of the 

 eyes, the thighs, and wings ; and then the Hver, 

 the lungs, and the heak. The foetus now begins 

 to move stnd to ftretch out its head, though no- 

 thing but the vifcera are yet formed ; for the 

 thorax, the abdomen, and all the external co- 

 verings of the fore part of the body, are ftill 

 wanting. At the end of this day, or the begin- 

 ning of the feventh, the claws begin to be vi- 

 fible J the chick opens and moves its beak ; and 

 the anterior parfs of the body begin to cover the 

 I'ifcera. On the feventh day, the chick is en- 

 tirely formed; and, from this time till it ifTues 

 from the egg, nothing happens but an expanfion 

 of all the parts it acquired during the firft feven 

 days. The feathers appear on the 14th or 15th 

 day; and, on the 21ft, the chick efcapes from the 

 €ggy by breaking the fhell with its bill. 



Thefe experiments of Harvey appear to have 

 been made with the greateft exadnefs and fide- 

 lity. We fhall afterwards, however, demonftrate 

 their imperfedion, and that the author has pro- 

 bably fallen into the common error of making 

 experiments, with a view to eftablifh his favou- 

 rite hypothefis, that the firft animated point 

 which appeared was the heart. But, before pro- 

 ceeding to this objed, it is proper to give an ac- 

 count of his other experiments. 



Every body knows the numerous experiments 

 made by Harvey upon female deer. They receive 



the 



