116 



" The fecundity of the hen is great ; she generally 

 lays 2 eggs in three days, and continues to lay through 

 the greater part of the year, except the time of 

 moulting." She lays 25 or 30 eggs before she pre- 

 pares to sit. The period of incubation is 2 1 days ; 

 the heat required to hatch the eggs, and which is the 

 heat of her body at the time of sitting is 104 of 

 Fahrenheit. 



The young chick when ready for hatching, is pro- 

 vided with a small hard calcareous protuberance at 

 the point of the bill, by which it is enabled the more 

 readily to break the shell, and which falls off some 

 hours after hatching.* 



* The egg or ovum of birds, consists of the following 

 parts : The shell, putamen ; the external membrane, mem- 

 brana albuminis ; air ce]\,folliculus aeris ; the white, albu- 

 mina ; the yolk, vitellus ; and the white spot on the supe- 

 rior surface of the yolk, cicatricula. 



Chemical analysis from Thomson's Dispensatory. 



The shell consists of carhonate of lime, phosphate of 

 lime, and animal mucus. When it is burnt, the carbonic 

 acid is dissipated, the animal cement destroyed, and pure 

 lime, with phosphate of lime obtained. 



The white is inodorous and insipid, of a glary viscid 

 nature, readily dissolving in water, coagulable by a heat of 

 165 Fahrenheit, and also by acids and alcohol. When 

 coagulated it becomes sapid, and is no longer soluble either 

 in cold or hot water. From the experiments of Dr. Bos- 

 toek, it appears to be composed of water 80.0, albumen 

 15.5. and mucus 4.5, in 100 parts; and besides shows 

 traces of soda, sulphureted hydrogen gas, and benzoic 

 acid. 



