ON GENERATION. 265 



For though the mother occasionally quits her eggs on va- 

 rious errands, it is only for a short season; she still has sucli 

 affection for them that she speedily returns, covers them over, 

 cherishes them beneath her breast and carefully defends them ; 

 and this on to the twenty-first or twenty-second day, when the 

 chicks, in search of freer air, break the shell and emerge into 

 the light. 



Now we must not overlook a mistake of Fabricius, and al- 

 most every one else in regard to this exclusion or birth of the 

 chick. Let us hear Fabricius. 1 



" The chick wants air sooner than food, for it has still some 

 store of nourishment within it ; in which case the chick, by his 

 chirping, gives a sign to his mother of the necessity of breaking 

 the shell, which he himself cannot accomplish by reason of the 

 hardness of the shell and the softness of his beak, to say nothing 

 of the distance of the shell from the beak, and of the position 

 of the head under the wing. The chick, nevertheless, is al- 

 ready so strong, and the cavity in the egg is so ample, and the 

 air contained within it so abundant, that the breathing becomes 

 free and the creature can emit the sounds that are proper to 

 it; these can be readily heard by a bystander, and were recog- 

 nized both by Pliny and Aristotle, 2 and perchance have some- 

 thing of the nature of a petition in their tone. For the hen 

 hearing the chirping of the chick within, and knowing thereby 

 the necessity of now breaking the shell in order that the chick 

 may enjoy the air which has become needful to it, or if you will, 

 you may say, that desiring to see her dear offspring, she breaks 

 the shell with her beak, which is not hard to do, for the part 

 over the hollow, long deprived of moisture, and exposed to the 

 heat of incubation, has become dry and brittle. The chirping 

 of the chick is consequently the first and principal indication 

 of the creature desiring to make its escape, and of its requiring 

 air. This the hen perceives so nicely, that if she hears the 

 chirping to be low and internal, she straightway turns the egg 

 over with her feet, that she may break the shell at the place 

 whence the voice proceeds without detriment to the chick. 



1 Op. cit. p. 59. 



2 Plin. lib. x, cap. 53. Arist. Hist. Anim. lib. vi, cap. 3. 



