EGGS l6l 



used in the preparation of other articles of food by cooking. Pure 

 butter, which represents the fatty constituents of milk, contains, in 100 

 parts, 30 parts of olein, 68 parts of palmitin, and 2 parts of other fats 

 peculiar to milk. The following is the composition of cow's milk 

 (Letheby): 



Nitrogenous matters ... 4.1 



Fatty matters ,'-.'' . . . 3.9 



Sugar . .;. . 5.2 



Inorganic matters . 0.8 



Water '.'..-. . 86.0 



IOO.O 



In connection with the composition of human milk, to be given 

 farther on, the great variety of its constituents will be more fully 

 considered. 



Egg s - As regards nutrition, the analogy between eggs and milk 

 is evident when it is remembered that the constituents of eggs furnish 

 materials for the growth of the chick, to which must be added certain 

 saline matters absorbed from the shell during the process of incubation. 

 Among the inorganic constituents of eggs, there is always a small 

 quantity of iron. The following is the composition of the entire 

 contents of the egg(Pavy): 



Nitrogenous matters . , . . . . . . . . 14.0 



Fatty matters . 10.5 



Inorganic matters . 1.5 



Water ............. 74.0 



IOO.O 



A number of different nitrogenous and fatty matters, a small quantity 

 of saccharine matter, as well as a great variety of inorganic salts, exist in 

 eggs. 



The physiological effects of a diet restricted to a single constituent 

 of food or to a few articles have been closely studied both in the human 

 subject and in the inferior animals. Animals subjected to a diet com- 

 posed exclusively of non-nitrogenous matters die in a short time with 

 symptoms of inanition. The same result follows when dogs are con- 

 fined to white bread and water ; but these animals live very well on the 

 military brown bread, as this contains a greater variety of alimentary mat- 

 ters (Magendie). Facts of this nature were multiplied by the "gelatin 

 commission," and the experiments were extended to nitrogenous sub- 

 stances and articles containing a considerable variety of alimentary 

 matters. In these experiments, it was shown that dogs could not live 

 on a diet of pure myosin, the appetite entirely failing at the forty-third 

 to the fifty-fifth day. They were nourished perfectly well by gluten, 



