THE VITAMINES IN THE VEGETABLE KINGDOM 53 



optimum concentration, this autolysate is no longer active and even 

 inhibits somewhat the growth of the cells a finding that is of greatest 

 importance for our arguments. He found later that the autolyzate 

 must be diluted to obtain the best results. Eeucine, tyrosine, and 

 asparagine have an inhibiting influence on the growth of yeast cells 

 but not on the lactic acid bacteria. Recently Lampitt (125) has 

 shown that the increase in the quantity of yeast cells depends on the 

 original number present. Evidently, this observation is to be 

 explained in this way : that due to excessive inoculation, a number of 

 dead cells are implanted at the same time and that the living cells 

 can utilize the vitamine set free. 



Since the growth of yeast cells might be utilized as a means for 

 the determination of antiberiberi vitamine, systematic investigations 

 were undertaken during the last two years for the purpose of studying 

 the vitamine requirements of these cells. It was expected in this 

 way to measure vitamine B, but we shall presently show that this 

 is not the case. In spite of the possibility that the substance pro- 

 moting the growth of yeast belongs to the type of B-vitamine, 

 newer work has shown that the substance promoting the growth 

 of yeast is not identical with vitamine B. It is possible, however, 

 that for yeast, an organism characterized by greater synthetic 

 ability, the cleavage products of vitamines might be sufficient, 

 whereas in higher animals, on the contrary, the entire vitamine 

 complex must be administered. 



In 1912, the author, using the fermentation method, endeavored 

 to show that vitamine could act as a co-ferment, but without success. 

 Abderhalden and Schaumann (126) were apparently more fortunate 

 and they described a phosphorus-free substance, obtained from 

 yeast, which could favorably influence the fermentation of certain 

 sugars. Abderhalden and Kohler (127) likewise described the 

 growth-promoting influence of some yeast fractions on the yeast 

 cells. The same authors also investigated the influence of yeast 

 extracts on growth of Flagellata (Colpoda). and Algae (Ulothrix) 

 with positive results. A whole series of experiments on this sub- 

 ject has lately been published in the United States. The method 

 of R. J. Williams (128) denoted progress in that it substituted for 

 fermentation a direct observation on the growth of yeast cells. 

 The method is as follows: A hanging drop is prepared so that it 

 contains the least number of yeast cells (one if possible) obtained by 



