210 THE VITAMINES 



given to beriberi pigeons, a cure could be obtained. This shows 

 that all the vitamine of the food is not assimilated, but that a portion 

 of it appears in the feces. Another explanation might be found in 

 the vitamine content of the bacterial intestinal flora, although Brad- 

 don and Cooper (551) noted only a small quantity of vitamine in 

 these bacteria. Portier and Random (I.e. 217) believed on the con- 

 trary that the vitamine of the intestinal canal arises from the bacteria. 

 Muckenfuss (552) found vitamine B in bile and urine, and was con- 

 firmed, as regards the latter, by Gaglio (553) and by Funk and Dubin. 

 Funk showed that when pigeons, which had died of beriberi, were 

 minced, extracted with alcohol, the extract concentrated, the residue 

 taken up with water and given to other beriberi pigeons, the latter 

 were promptly cured. This experiment, corroborated by Theiler, 

 Green and Viljoen (I.e. 278) showed definitely that animals develop 

 beriberi in spite of the fact that they still have vitamine in their 

 tissues. It seems that a portion of the vitamines in the tissues (per- 

 haps as a constituent of the cell protoplasm) is so combined that the 

 animal itself cannot utilize it. Another explanation of this is to 

 be found, perhaps, in the work of Green on pigeons (I.e. 526); he 

 noted that the animal organism requires a rather definite amount of 

 vitamine for normal health. This really seems to be the case, and 

 as the quantity drops below the minimal need, it leads to an 

 avitaminosis. The quantity of vitamines that may be liberated from 

 the organs normally is very small. If the animal is given a diet poor 

 in vitamine, it might be thought that the animal would consume 

 more of the food in order to obtain the necessary vitamine; but this 

 is not the case. It was supposed by Osborne and Mendel (554) that 

 some foodstuffs contain sufficient vitamine for rats, if these animals 

 would but ingest more of this food mixture. But it is right here 

 that we meet with a difficulty that is also of practical importance, 

 namely, the question of vitamine dilution in the natural foodstuffs. 

 With every diet prepared, the needed amount of vitamine must be 

 supplied if the diet is to prove satisfactory. 



THE INFLUENCE OF DIETARY COMPOSITION ON THE VITAMINE 

 REQUIREMENT 



Regarding the influence of a large or small addition of a vitamine- 

 free diet on the occurrence of beriberi, the literature is full of conflict- 

 ing opinions. While Maurer (555) and Cooper (I.e. 536) stated that 



