148 



HABITS OF BIRDS. 



In about twelve hours from the time the mother 

 begins to sit, the commencement of life is percep- 

 tible in the germ (cicatricula) . What seems to be 

 the head of the chick appears joined to the body 

 and swims in the surrounding fluid; and towards 

 the close of the first day this apparent head is seen 

 bent back by its enlargement. So says Haller ; but 

 Blumenbach thinks this a deceptive appearance, pro- 

 duced only by the destined abode of the future chick, 

 no trace of which, he says, is perceptible before the 

 second day, when it assumes an incurvated form 

 resembling a thread of jelly enlarged at the extremi- 

 ties, very closely surrounded by fluid, from which it 

 is scarcely distinguishable. The first appearance of 

 red blood is perceptible on the yolk-bag towards the 

 end of the second day, a series of points being ob- 

 served which form grooves ; these closing consti- 



An Ee? as it appears sixteen hours after incubation, with a magnified view 

 of tlie Embryo Chick. 



