6 Fractiotiation of Phosphotungstic Acid Precipitate 



The first possibility, destruction by alkali, is dealt with in the 

 present paper. Several fractionings were performed without the 

 use of alkah. Because vitamine is very labile it seemed desirable to 

 separate, early in the procedure if possible, the bulk of the impurities 

 from the phosphotungstate precipitate. For this purpose acetone 

 was used. While this work was in progress it was found that 

 Wechsler (9) had already described the solubility of several phos- 

 photungstates in dilute acetone. By treating the phosphotungstates 

 obtained from hydrolyzed alc. extracts of yeast, with acetone in a 

 mortar, it was found that a very small part of the precipitate re- 

 mained insoluble. Testing both the insoluble and the soluble parts 

 on beriberi pigeons, it was found that all the vitamine remained in 

 the small insoluble fraction. This result was very promising, for 

 the bulk of the impurities remained behind. The phosphotung- 

 states thus obtained were not decomposed with baryta but with 

 neutral lead acetate. After evaporation of the lead-free acetone- 

 insoluble fraction, the whole residue crystallized out. With this 

 residue a series of curative experiments were performed which are 

 described elsewhere (8, 10). The product proved to be highly 

 curative and, given with polished-rice, kept the animals in perfect 

 health. 



This product was fractioned further, on several occasions; it 

 consisted chiefly of adenin. After separating the latter substance 

 with picric acid, the vitamine was found in the mercuric-chlorid 

 fraction ; it was not precipitated by platinic chlorid, in accord with 

 previous findings. Vitamine has not yet been obtained in a crystal- 

 lin State from the platinic-chlorid filtrate, but has been reprecipi- 

 tated with mercuric chlorid, although the yield has not been sufficient 

 for further investigation. 



Since these results were very promising, attempts were made to 

 isolate vitamine from autolyzed yeast, which, as was found by 

 Cooper (11), contains as much vitamine as does the corresponding 

 amount of fresh yeast It was thought best to combine the use of 

 autolyzed yeast and of the acetone method, and it was proposed to 

 separate the impurities from the vitamine at the phosphotungstate 

 stage. For this purpose the solubility of the phosphotungstates of 

 several bases occurring in nature, when in Solution in different or- 



