NOVEMBEE 24, 1911] 



SCIENCE 



729 



fat form the sole ingredients." That the 

 stunted or malnourished rats in these earlier 

 experiments have not lost their capacity to 

 grow or, in the case of the adults, have not 

 become permanently disorganized from a nu- 

 tritive standpoint can be readily demon- 

 strated; for they will resume growth or become 

 realimented, as the case may be, as soon as 

 mixed food is furnished. The milk mixtures 



SAo 



Obviously the milk contains the nutrient 

 elements essential to success which had previ- 

 ously not been satisfactorily imitated in the 

 artificial food mixtures. It occurred to us to 

 attempt to locate these as yet unknown com- 

 ponents by removal of the proteins from milk 

 and concentration of the protein-free (and fat- 

 free) residues. The product thus obtained 

 (and which may conveniently be termed " pro- 



FlG. 7. Showing the realimentation of a rat praetieally moribnnd, by the addition of 

 protein-free milk to the diet containing a single protein (casein). 



are as efficient as mixed food in promoting 

 growth and restoring nutritive equilibrium. 



Eats have been carried through two genera- 

 tions on a food mixture of the following com- 

 position : 



Per Cent 



Miltpowder 60.0 



Starch 15." 



Saltmirture 1-0 



Lard 23.3 



100.0 



" The dried milk used is the commercial ' ' Tm- 



tein-free milk-*"*) has fulfilled our expecta- 

 tion and enabled us at length to study the 

 relative value of added proteins in the dietary. 

 The protein-free milk contains the milk sugar 

 in addition to inorganic salts and other as yet 

 unknown components of the mil k . Whether 



milk, " famished by the MerreH-Sonle Co., of 

 Syracuse, IN'. Y. 



^A detailed description of the preparation and 

 composition of protein-free milk is given in the 

 detailed papers, Part H. 



