VITAMIN G (5o) 123 



rapidly accumulating evidence of at least two water-soluble growth- 

 promoting factors by a series of experiments in which various extracts 

 and preparations of yeast and of wheat embryo were used singly and 

 combined as the source of vitamin B in preventive and curative tests on 

 rats. A concentrate of the antineuritic vitamin prepared by the Peters' 

 method (vitamin extracted from charcoal concentrate by 50 per cent 

 acidified alcohol) was found to be ineffective for growth until supple- 

 mented in this case by yeast heated at 120° C. for 5 hours, when recovery 

 and normal growth ensued. The autoclaved yeast by itself had no effect 

 in curing the paralytic symptoms sometimes developing in rats on a 

 vitamin B-deficient diet, but promptly relieved a pellagra-like condition 

 similar to that described by Goldberger and by Salmon and observed 

 to occur frequently when the Peters' concentrate constituted the source 

 of vitamin B. Brewers' yeast was shown to be rich in both these factors 

 and pure wheat embryo to be rich in the antineuritic vitamin, but de- 

 ficient in the heat-stable factor ; the Peters' concentrate was considered 

 to be a good source of antineuritic vitamin uncontaminated by the heat- 

 stable factor, and autoclaved yeast to be devoid of the antineuritic 

 vitamin. 



Evidence of a more quantitative nature as to the supplementing 

 growth-promoting action of one material for another and therefore of 

 the existence of more than one water-soluble growth-promoting vitamin 

 was obtained by Sherman and Axtmayer (1927) working with ground 

 whole wheat, autoclaved yeast and dried skimmed milk as sources of 

 vitamin B in quantitative feeding experiments. They fed comparable 

 groups of rats the basal diet alone, or the basal diet supplemented by 

 0.8 gram daily of ground whole wheat, 0.8 gram of autoclaved yeast 

 or 0.4 gram each of the wheat and yeast. The autoclaved yeast was 

 incapable of sustaining growth as the sole source of water-soluble vita- 

 mins but was effectively supplemented by the wheat. Since autoclaving 

 tends to destroy the heat-labile vitamin B the limiting factor for growth 

 in wheat must be vitamin G. Using skim milk as a source of both 

 vitamins, and supplementing it with autoclaved yeast and ground whole 

 wheat respectively, it was found that vitamin B is the limiting factor 

 in cow's milk, or that milk is relatively richer in vitamin G than in 

 vitamin B while the reverse is true of wheat. 



Salmon, Guerrant and Hays (1928), in fractionating an acidulated 

 aqueous extract of velvet bean leaves, by treating the extract with 

 fuller's earth, obtained a preparation which prevented beriberi in 

 pigeons in daily doses of 0.01 gram but did not promote growth in rats 

 in doses as high as 0.1 gram daily. They estimated that more than one- 



