178 



THE VITAMINES 



melting at 233 C. This substance from yeast was therapeutically 

 active; 2 to 4 centigrams were sufficient to cure a sick pigeon in a 

 short time; smaller doses were not tried. The substance could be 

 precipitated by mercuric acetate but not by the nitrate or sulphate. 

 It gave no precipitate with a nitron solution showing the absence 

 of nitric acid and had a neutral reaction. No blue cop*per salt 

 was obtained with copper oxide, which would indicate that the 

 substance is not an amino-acid. The filtrate from the silver pre- 

 cipitate was inactive. 



FlG. 40. MlCROPHOTOGRAPH OP CRYSTALS OBTAINED FROM VlTAMINE FRACTION 

 OF YEAST, POSSESSING CURATIVE ACTION 



Another batch of yeast was treated in a somewhat different manner. 

 The alcoholic extract, after concentration in vacuum, was simply 

 taken up with water, and not hydrolyzed as above. Thus the 

 vitamine was obtained in watery solution. This was then pre- 

 cipitated with phosphotungstic acid and treated as above; in this 

 case however, the silver fraction did not yield an active product, a 

 substance being isolated which could be identified as uracil. All the 

 vitamine, in this case, was found in the filtrate from the silver nitrate 

 precipitate, which might mean that the vitamine of yeast occurs 



