THE ANTIBERIBERI VITAMINE 187 



Phosphotungstic acid precipitate from yeast. 



Acetone insoluble part Acetone soluble part 



Picrate Picric acid filtrate 



l| 



II \ 



Sublimate precipitate Sublimate filtrate 



Platinic chloride precipitate 



Filtrate 



Sublimate precipitate Sublimate filtrate 



phosphotungstic acid in the above method was substituted by phos- 

 photitanic acid. Cooper (492) then showed that when pressed yeast 

 is allowed to stand for 35 hours at 35 C., the mass becomes 

 semi-liquid and on filtration from the cell residue, a. liquid called 

 "autolyzed yeast" is obtained, which contains almost all of the 

 vitamine of the yeast. It was shown later that the yeast con- 

 stituents are not completely autolyzed, since if the liquid is heated 

 to 60 to 70 C., an appreciable amount of protein separates out. 

 When the acetone method was applied to this liquid, the amount of 

 the acetone insoluble portion was much larger about 1125 grams 

 from 5 kilos of pressed yeast. We then showed that when the 

 phosphotungstates of choline, betaine, stachydrine, guanine, adenine, 

 guanidine, creatinine and nicotinic acid were tested for their 

 solubility in acetone-water solutions of various dilutions, the sol- 

 ubility was as follows : 



25 per cent acetone > 100 per cent > 50 per cent > 75 per cent 



Choosing these four concentrations, the solubility was least in 25 

 per cent acetone and greatest in 75 per cent acetone. We were then 

 able to show, in our work with Dubin (493), that autolyzed yeast 

 contains much more vitamine than vitamine extracts obtained from 

 yeast by various solvents. For this reason, autolyzed yeast would 

 be superior to all other extracts for the purpose of vitamine fraction- 



