222 THE POULTRY-BOOK. 



First and Last Stages of Incubation. 



At the end of the second day, it assumes the form of a 

 horse-shoe, but no red blood as yet is seen. 



At the fiftieth hour, two vesicles of blood, the rudiments of 

 the heart, may be distinguished, one resembling a noose folded 

 down on itself, and pulsating distinctly. 



At the end of seventy hours, the wings may be seen ; and, 

 in the head, the brain and the bill in form of bubbles. 



Towards the end of the fourth day, the heart is more com- 

 pletely formed ; and, on the fifth day, the liver is observable. 



At the end of a hundred and thirty hours, the first voluntary 

 motion may be observed ; in seven hours more, the lungs and 

 stomach appear ; and, in four hours after this, the intestines, 

 the loins, and the upper jaw. 



At the end of the one hundred and forty-fourth hour, two 

 drops of blood are observable in the heart, which is also fur- 

 ther developed. 



On the seventh day, the brain exhibits some consistence. 



At the hundred and ninetieth hour, the bill opens, and the 

 muscular flesh appears on the breast ; in four hours more, the 

 breast-bone is seen ; and, in six hours after this, the ribs may 

 be observed forming from the back 



