THE ANTIBERIBERI VITAMINE 



199 



The methods of R. J. Williams (528) and of Funk and Dubin (I.e. 

 511) then appeared almost simultaneously, both signifying a step 

 forward in the demonstration of the part played by the vitamines 

 in yeast growth. The method of Williams is as follows : 0.3 gram of 

 ordinary fresh bakers' yeast was removed from the center of a yeast 

 cake and suspended in a liter of sterile water. Of this suspension, 

 1 ec. was introduced into the nutritive solution and the cultures kept 

 in the incubator at 30C. for eighteen hours, after which growth was 

 stopped by the addition of formalin. The yeast cells were then 



12 

 E ' 



O) 



f 6 



CD 



I 6 



-(- 



4 



CO 



<D 



1 2.. 3 4 -5 



Vitamine solution cc. 



FIG. 47. INFLUENCE OF VITAMINE B CONCENTRATION ON YEAST GROWTH 



(WILLIAMS) 



filtered on a Gooch crucible, washed with water and alcohol and 

 dried at 103C. for 2 hours. With a vitamine solution of a source 

 not mentioned, a growth curve was obtained, reproduced herewith. 

 He showed that with higher vitamine concentrations, the quantity 

 of cells rose proportionally and that under certain conditions, the 

 curve approaches a straight line. Williams also observed that certain 

 extracts such as autolyzed yeast, or extracts heated to a high tem- 

 perature in the presence of acids, could exert an inhibiting influence 

 on the growth of yeast. In such cases, an abundant dilution is of 

 great help and yields better results. 



