Deficiency of which causes Beri-beri m Man. 



57 



gained by the seven birds in these two experiments was 72 grm., or a gain of 

 about 10 grm. per bird. 



In Expt. 3, Table I, and Expt. 2, Table II, where 2 grm. wheat germ was 

 given every second day, and polyneuritis was not prevented with certainty, 

 there was an average loss of weight of 16 and 10 per cent, respectively, or a 

 total loss of 365 grm. among the eight birds studied, i.e., 46 grm. per bird. 



The average difference in weight between individuals in the above two 

 series of experiments is therefore 56 grm. This must be referred to a 

 difference in diet amounting to 0'5 grm. wheat germ daily over a period of 

 about 60 days, i.e., a total of 30 grm. per head. It is therefore evident that 

 the addition to a diet of polished rice of wheat germ in amount to prevent 

 polyneuritis has also some influence in promoting the general metabolism 

 of the animal. 



This result is in accord with the observation of Schaumann (1911), who 

 found that if a ration of a vitamine-containing foodstuff (such as rice-bran 

 or yeast) were adequate to prevent onset of polyneuritis in birds, when added 

 to a diet of polished rice, loss of weight was prevented, whereas extracts 

 of these foodstuffs prepared by extraction with acid or alcohol, sufficient 

 to prevent polyneuritis, did not maintain weight. 



Our experiments with wheat-bran offer another example of this principle. 

 Where the bran was free from germ, as in sample E.I. (Table III), a ration 

 of 5 grm. each second day did not prevent polyneuritis, nor did it maintain 

 weight. In case of sample A, which was stone-milled, and presumably 

 contained traces of germ, a ration equal to 5 grm. each second day more 

 nearly protected a pigeon from polyneuritis, and there was no appreciable 

 loss of weight. 



Cooper (1913) came to the conclusion that the substances preventing poly- 

 neuritis and maintaining body weight were separate and might be separately 

 distributed in natural foodstuffs. For certain of these, e.g. yeast, ox-heart and 

 ox-brain, the two substances were evenly balanced and the daily ration 

 required to prevent polyneuritis also maintained the weight of the bird. In 

 others, e.g. egg- yolk, barley, lentils, this daily ration had to be increased if 

 loss of weight were also to be prevented. In this connection our experiments 

 in which casein was added to a diet of polished rice (set out in Table VII) are 

 of some interest. The casein, prepared from milk by precipitation and 

 subjected to some purification, proved to be vitamine-free, as was expected ; 

 the addition of the extra protein had no influence upon the onset of poly- 

 neuritis. AVith the addition to the diet of 3 grm. of this casein daily, however, 

 the weight of the birds was certainly maintained better than was the case 

 with the control birds fed on polished rice alone. 



