134 



FEEDING EXPERIMENTS WITH ISOLATED FOOD-SUBSTANCES. 



form of protein-free milk. Period 2 shows the influence of the substitution 

 by casein of one-fourth of the gliadin in a dietary repeatedly shown to suffice 

 for maintenance but not for growth. This emphasizes the different nutri- 

 tive value of casein and gliadin. The composition of the diets was as shown 

 below. 



Chart CXXIII. 



180 



160 



140 



120 



100 



80 

 m 

 E 



/ 



Casein'food- 



xGliadin + Protein-free milk 75%^ 

 ^Xaseih+ ,-u 41 I 25% 



20 40 60 80 100 120 



Days 



140 



160 180 



Chart CXXIII (rat 173, male). Period 1 shows imperfect maintenance 

 without growth on a diet containing salt mixture I (no protein-free milk) 

 and casein as the sole protein. This should be contrasted with numerous 

 similar experiments in which the inorganic constituents of the diet were 

 present in the form of protein-free milk. Period 2 shows the influence of the 

 substitution by casein of one-fourth of the gliadin in a dietary repeatedly 

 shown to suffice for maintenance but not for growth. This emphasizes the 

 different nutritive value of casein and gliadin. The composition of the 

 diets was 



