IQIS] 



Casimir Funk 



347 



centage composition of each of the diets is indicated in the appended 

 summary : 



Diet IV 



Casein 



Starch 



Unpolished rice. 

 Polished rice. . . 



Sugar 



Lard 



Salt mixture . . . 



22 

 29 



12 

 21 

 12.4 

 2.6 



The experiment with polished rice terminated very early — in 29 

 days, all the animals dying without any sign of growth. The 

 unpolished-rice experiment continued for 61 days. The best results 

 were obtained with Diet III, which contained the largest amount of 

 unpolished rice. If we take, for convenience of comparison, a 

 period of 28 days we find the following average figures in the 

 records of these experiments. On Diet I the rats show a weight-loss 

 of 3 percent; on Diet II, there was a gain of 7 percent; on Diet III, 

 a gain of 16 percent. The chief chemical difference between pol- 

 ished rice and unpolished rice, so far as we know, is the diflference 

 in the proportion of vitamine. These results suggest very strongly 

 that vitamine plays an important if not a decisive role in the experi- 

 ments on growth. 



An experiment similar to the one described above was per- 

 formed by McCollum and Davis (146). They compared the bio- 

 logical properties of corn-meal, wheat, wheat-embryo, rye, and 

 rolled oats with dry pig-heart or kidney. The experiments, which 

 were carried out on rats, demonstrated the beneficial effect, on 

 growth, of corn-meal and wheat-embryo, the addition of rye had a 

 slight favorable effect, but whole wheat-grain and rolled oats had 

 practically no effect. The addition of pig-heart had less effect than 

 the addition of kidney. These experiments show that food-stuffs 

 known to contain a relatively large amount of vitamine stimulate 

 growth, in rats, better than do those that contain relatively little 

 vitamine. 



As the results so far obtained sufficiently demonstrate the im- 

 portance of vitamines for the growth of rats, Macallum and I have 

 Started new experiments with diets including different fractions 

 from yeast. These experiments are now in progress. 



