FEEDING EXPERIMENTS WITH MICE 223 



SUMMARY 



The experiments here reported have demonstrated the avail- 

 abiUty of mice for nutrition investigations of this sort. White 

 mice have been kept in health for six months on an 'artificial' 

 diet containing a single protein, casein, and for periods of from 

 one to five months on similar foods in which the casein was re- 

 placed by lactalbumin, by either of the chief proteins of wheat, 

 or by edestin. Gelatin and zein cannot replace more than one- 

 half the protein in the food of mice; and in the case of gelatin at 

 least, an even smaller proportion than that must be used if there 

 is to be repair as well as maintenance. The nutritive require- 

 ments for growth may be quite different from those for mainte- 

 nance only; and experiments in feeding with milk food indicate 

 that mice require a higher percentage of protein and of ash for 

 growth than do the slower growing rats. The capacity to grow 

 is not necessarily lost during youth; for an increase in weight 

 more rapid than the normal sometimes takes place after long 

 periods of stunting. 



The investigation was undertaken at the suggestion of Prof. 

 Lafayette B. Mendel, to whom the author's sincere gratitude is 

 due. 



