THE ANTIBERIBERI VITAMINE 203 



and not always so that some effect was noticeable. This protrac- 

 tion of the influence showed that the accelerative action of glucose 

 was of a secondary nature, and might perhaps be explained by the 

 plasmolysis of some yeast cells. When de Souza and McCollum speak 

 of the favorable action of amino acids, they mean by that a product 

 resulting from the sulphuric acid hydrolysis of meat. This prepara- 

 tion, as well as an alcoholic extract of wheat germ, was shown to be 

 free from vitamine B in rat experiments, while they were still active 

 for yeast. Hydrolyzed meat gave only double the amount of cells, 

 so that the action was not so pronounced. These investigators 

 admitted that their experiment did not demonstrate that vitamine B 

 played no part in the growth of yeast, they likewise showed that the 

 growth of rats and yeast does not go parallel with the same extracts. 

 The question as to the identity of vitamine B with the substance, 

 promoting the growth of yeast will be discussed in the next section. 

 Newer investigations have shown that the yeast test is of value 

 in determining the relative richness of extracts in water-soluble 

 vitamines, but cannot be used for the quantitative determination 

 of vitamine B. 



THE POSSIBLE IDENTITY OF VITAMINE B WITH THE SUBSTANCE 

 STIMULATING THE GROWTH OF ANIMALS AND OF YEAST 



We have already (p. 41) touched upon the question raised by 

 Mitchell (I.e. 93) as well as by Emmett and Luros (I.e. 94), as to 

 the identity of these substances. As regards the comparison of 

 vitamine B with the substance promoting the growth of rats, Funk 

 and Macallum (530) showed that the latter substance could be 

 precipitated with phosphotungstic acid, whereupon further fraction- 

 ation was tried. Since the diet we used at the time did not contain 

 sufficient vitamine A, the results were not particularly fruitful, and 

 seemed to indicate that pigeons require less vitamine B for protection 

 against beriberi than do rats for growth, or that vitamine B is more 

 stable than the growth vitamine. Drummond (I.e. 498) corrob- 

 orated our findings and came to the conclusion that, in all prob- 

 ability, both substances are identical. Emmett and Luros (I.e. 94) 

 seem to have a different opinion on this matter. They investigated 

 the effect of autoclaving at various temperatures for various periods 

 of time. On the one hand, these products were given, as such, to 



