THE ANTIBERIBERI VITAMINE 189 



from fuller's earth preparations by Rhodehamel and Stuart (496b). 

 Recently, Seidell (496c) has combined the fuller's earth method 

 with our silver method and has obtained some promising results. 

 He liberates the vitamine with a baryta solution, the procedure 

 being hastened as much as possible. From the filtrate, the purine 

 bases are eliminated with silver nitrate while the vitamines are 

 precipitated by ammoniacal silver nitrate. This fraction can be 

 reprecipitated in the same way and can be analyzed for its silver 

 content. A crystalline substance was isolated from this fraction, 

 but it proved inactive, showing it to be a fairly complicated mixture. 

 We found that nicotinic acid is also precipitated by ammoniacal 

 silver nitrate. For the liberation of vitamine from activated fuller's 

 earth, we have likewise used ammonia and pyridine; we were also 

 able to confirm the findings of Eddy, Heft, Stevenson and Johnson 

 (I.e. 129e) that vitamine can be adsorbed with a specially pre- 

 pared charcoal from which it can be liberated with glacial acetic 

 acid. Voegtlin and White (497) adsorbed the vitamine with mastic, 

 and with colloidal arsenic sulfide, in which case the impurity was 

 guanine instead of adenine. 



Drummond (498) attempted to confirm our findings on vitamine 

 B, and although he was able to do so for the most part, he concluded 

 that our chemical work was of no particular significance, because he 

 held that the vitamines were not precipitated by the various pre- 

 cipitation methods, but were adsorbed by the precipitates. The 

 characteristic, adsorbability, is peculiar to many pure chemical sub- 

 stances. We need only recall Lloyd's reagent which, as we have 

 personally proved by tests on rats, quantitatively adsorbs strychnine 

 and other alkaloids. Pure glucose is also adsorbed in very appre- 

 ciable amounts by various kinds of blood charcoals. Besides, Drum- 

 mond carried out the silver nitrate-baryta precipitation in a manner 

 different from ours, and used rats as experimental animals, which, 

 as we shall see, behave differently than do pigeons and chickens. 



Abderhalden and Schaumann (499) have recently published con- 

 siderable work on yeast, which unfortunately is described so 

 unclearly that it is hard to state whether or not progress has been 

 made. These authors declare, in accord with the phosphorus theory 

 of Schaumann, that vitamine B of yeast occurs as a nucleoproteid. 

 They were able to isolate an active nucleoproteid from yeast. 

 Pigeons receiving a half gram of this substance daily lived for 70 



