172 THE VITAMINES 



Because of the small yield, it could not be investigated further. After 

 the publication of our findings, Schaumann (468) undertook some 

 experiments with rice polishings, using our method. He obtained 

 a small amount of a crystalline substance from the sublimate fraction, 

 and demonstrated that it was active. He was able to confirm our 

 work, but he could not effect a complete isolation. Later, a great 

 number of investigators tried to verify our findings and succeeded, 

 at least as far as the vitamine fraction was concerned. Among these, 

 we wish to mention Wellman, Eustis and Scott (469), as well as 

 Eustis and Scott (470). Vedder and R. R. Williams (471) obtained, 

 with our method, a crystalline base that was therapeutically active. 

 They found that unhydrolyzed extracts acted more slowly than the 

 hydrolyzed. Besides this, they observed that the vitamine was not 

 completely soluble in 95 per cent alcohol, and was destroyed by strong 

 alkali; it appeared also that it could not be precipitated by basic 

 lead acetate. The same results were obtained by R. R. Williams and 

 Saleeby (472), substantiating the silver nitrate-baryta method. 

 Later, Williams (473) described various modifications of our method. 

 Issoglio (474) also found that phosphotungstic acid precipitates the 

 vitamine. Subsequently, the isolation of vitamine from rice polish- 

 ings was attempted by Kondo and Gomi (475) and by Murai (476) .* 

 Brill (479) tried to concentrate the vitamine by adsorption with 

 infusorial earth, but this procedure was not very suitable. Fraser 

 and Stanton (480) also conducted some experiments, attempting to 

 extract and isolate the vitamine. 



A much more interesting paper was published in 1912 by Suzuki, 

 Shimamura and Odake (I.e. 466). They extracted fat-free rice 



1 Some patents have been taken out on the isolation of vitamines from rice 

 polishings. That of Tsuzuki (477) was nothing more than a concentrated 

 alcoholic extract of rice polishings. In addition, there is the patent of Gams 

 and Schreiber (478) and the identical patent of the Society for Industrial 

 Chemistry at Basle, which briefly is as follows : the purification of the extract 

 of rice polishings, which is supposed to contain very little inactive material, 

 consisted of a precipitation with lead acetate, first in acid and then in neutral 

 solution. Then the filtrate was precipitated by alkaloidal reagents, like 

 phosphotungstic acid or oxalic acid, and the resulting precipitate decom- 

 posed in a watery solution with calcium carbonate. By this means, a syrup 

 was obtained which was soluble in methyl but not in absolute ethyl alcohol, 

 ether and acetone; it gave a strong diazo reaction. The product is sold under 

 the name of "Orypan." 



