INCUBATION OF AN EGG 



loses daily 0.0018 in specific gravity, principally from 

 the exhalation of carbon dioxide. 



The process of incubation by which the simple 

 cellular mass of plasmodium is converted into the 

 living chick is simply the same process that takes 

 place in the germination and growth of a seed, only 

 that a higher temperature is requisite for its origin 

 and continuance. When the hen has laid as many 

 eggs as she can cover usually about a dozen an 

 irresistible desire to "set" overcomes her. The 

 sitting hen is in a curious, peculiar state. She seems 

 to present all the symptoms of fever, her eyes are 

 sparkling, her skin burning, she drinks more than 

 she eats. To see her ardor one would say that she 

 comprehends the importance of the function that she 

 exercises. Buffon says : " But what is most remark- 

 able is that the attitude of a sitting hen (une cou- 

 veuse), however wearisome it may appear to us, is 

 perhaps less a source of ennui than it is a state of 

 continued enjoyment. The more delightful because 

 it is inherited, for nature seems to have placed a 

 charm in all that has relation to the multiplication of 

 the species." 



The temperature required for incubation is 105 



degrees F., continued for twenty-one days. This is 



afforded by the animal heat of the sitting hen, but 



is equally effective if furnished from any other 



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