190 THE VITAMINES 



days. We have already seen that such findings possess no special 

 significance, since the activity of the nucleoproteid might have 

 been due to adsorption, as with fullers earth. The authors also 

 assume that the mother substance of the vitamine varies according 

 to the source of material. The vitamine was obtained from yeast 

 extracts by precipitation with acetone, and purified by several 

 reprecipitations. This crude fraction was investigated physiologi- 

 cally, and found curative for beriberi, but it could not keep pigeons 

 alive for any prolonged period. Another preparation was obtained 

 from yeast by treatment with alkalis. This substance did not cure 

 beriberi, but when added together with the acetone preparation, its 

 effect was to prolong life. A number of substances were isolated from 

 the acetone preparation, by reprecipitating with sublimate, among 

 which there was apparently only a single new substance obtained in 

 the pure state. This base, called "Aschamine" had the structure of 

 dimethylpropenylamine, the formula being 



CH = CH CH 2 



/ 

 C 5 Hi 3 O N = OH N CH 3 



\ 



CH 3 

 H 



it was inactive for beriberi. In the other fractions, betaine was 

 found as an impurity. All of these substances were prepared from 

 hydrolyzed yeast, and the authors believed that the active substance 

 belonged to the betaine group, having its characteristic structure. 

 In a later experiment, Abderhalden (500) states that the active 

 substance cannot be quantitatively removed from yeast by absolute 

 alcohol or absolute alcohol and acetone. 



Sugiura (501) placed yeast and also carrot extracts in collodion 

 sacs, and permitted the contents to dialyze through the membrane, 

 whereupon the product crystallized on the outside of the membrane. 

 It was evidently hoped to prepare the active substance in the pure 

 state by this simple procedure, but naturally the entire yeast mixture 

 dialyzed out. 



Osborne and Wakeman (502) described a method which promised 

 greater success. The procedure consisted chiefly in eliminating 

 the autolysis of the yeast cells by washing them and boiling with 

 water, to which some acetic acid has been added, thus coagulating 



