I06 FEEDING EXPERIMENTS WITH ISOLATED FOOD-SUBSTANCES. 



Chart LV. 



Chart LIV. 220 



200 



20 40 60 80 100 120 140 m 



Days i 



Period 2. 



p. ct. 



Casein 18.0 



Protein-free milk. 28.2 



Starch 23 . 8 



Agar SO 



Lard 25.0 



Chart LIV (rat 204, female) shows uninterrupted 

 growth when a diet of isolated food-stuffs containing 

 casein as its sole protein was substituted for mixed food. 

 The requisite inorganic salts were furnished in the added 

 protein-free milk. The experiment is of exceptional inter- 

 est inasmuch as the animal successfully passed through two periods of 

 pregnancy on a purine-free food containing a single protein. This obviously 

 affords a method of studying various synthetic processes in the animal body. 

 The diet during period 1 consisted of mixed food. During period 2 as shown 

 herewith. 



Chart LV (rat 203, male) shows uninterrupted 

 growth when a diet of isolated foodstuffs containing 

 casein as its sole protein was substituted for mixed food. 

 The requisite inorganic salts were furnished in the added 

 protein-free milk. The diet during period 1 consisted of 

 mixed food; during period 2, as shown herewith. 



Period 2. 



p. ct. 



Casein 18.0 



Protein-free milk . 28 . 2 



Starch 23.8 



Agar 5-0 



Lard 25.0 



