Casimir Funk 3 



cleared with lead acetate, and Immediately precipitated with silver 

 nitrate. This precipitate, when decomposed, gave a small quan- 

 tity of crystallin organic substance that yielded ash. These authors 

 did not Claim, however, to have tested the curative power of this 

 substance. 



Later in 19 12 the author endeavored (3) to isolate the vitamine 

 frbm different foodstuffs, e. g., yeast, ox-brain, milk, rice-polish- 

 ings and lime-juice. To indicate some of the experimental diffi- 

 culties that are encountered in this kind of work, these attempts may 

 be briefly described. 



RiCE-POLiSHiNGS. An extract of rice-polishings was precipi- 

 tated directly with silver nitrate and baryta. This process was 

 chosen to shorten the procedure and to avoid the use of a large 

 quantity of alkali, which was supposed to destroy the vitamine. 

 No vitamine was detected in this case. AUantoin was found, which, 

 when phosphotungstic acid is used, goes into the filtrate. 



Yeast. The evaporated alc. extract of yeast was hydrolyzed 

 for a short time previous to precipitation with phosphotungstic 

 acid, with 10 percent sulfuric acid sol., preliminary experiments in 

 collaboration with E, A. Cooper having been shown that even after 

 prolonged hydrolysis with strong sulfuric acid sol. (4) the contained 

 vitamine remained active. The hydrolyzate was worked up in a 

 w^ay similar to that for the first fractionation of the extract of rice- 

 polishings, with the difference that Sublimate was not used. The 

 silver-fraction, when decomposed, yielded a crystallin substance, 

 melting at 233°C., that gave a precipitate with mercuric acetate, but 

 not with mercuric sulfate or nitrate.. No copper salt was formed 

 in boiling water with copper oxid. The yield, 0.45 gm. from 75 k. 

 of dry yeast, was too small for recrystallization or analysis; a 

 rather large dose of the substance (0.02-0.04 gm.) proved, however, 

 to be curative for beriberi pigeons. In another fractionation of 

 yeast the alc. extract was simply extracted with water and not hydro- 

 lyzed ; in this case the substance described above could not be iso- 

 lated but some pyrimidin bases, e. g., uracil and thymin, were ob- 



tained. 



Milk and brain. Milk and brain were extracted with alcohol, 

 the evaporated alc. extracts hydrolyzed with acid, and worked up 



