128 THE VITAMINS 



per cent alcohol containing 0.1 per cent sulfuric acid used in 2 successive 

 extractions of 1 hour each at 60° to 70° C. ; 50 per cent alcohol con- 

 taining 0.1 per cent sodium hydroxide ; and hydrochloric acid (pH 6.8). 

 Under the latter condition the potency of the solids was reduced, but 

 the extracted material was inactive. Norite appeared to be a much less 

 satisfactory adsorbent than fuller's earth. 



Concentrating an aqueous extract (pH 6.8) to a thick syrup and 

 extracting this product with 50 per cent alcohol appeared to inactivate 

 the vitamin completely. 



Eighty-eight per cent of the vitamin Ba (G) in the filtrate resulting 

 from the decomposition of the lead acetate precipitate remained in the 

 supernatant liquid and washings when the fraction was brought to a 

 concentration of 50 per cent alcohol. When the concentration of alcohol 

 was increased to 70 per cent, the supernatant fluid was inactive and the 

 precipitate contained most of the vitamin (active in daily doses of 6 

 milligrams organic matter). 



These investigators found no appreciable destruction of vitamin 

 Ba (G) when the yeast extract was boiled with 10 to 15 per cent sulfuric 

 or hydrochloric acid for 24 hours, or treated with 10 to 15 per cent 

 barium hydroxide at 110° to 120° C. for from one to three hours. The 

 vitamin appeared to be stable to hydrogen peroxide and to nitrous acid. 

 It seemed very soluble in water and in 50 to 60 per cent alcohol, but 

 only sparingly soluble in alcohol of higher concentrations and practically 

 insoluble in higher alcohols, as butyl. 



None of the following substances was found active as vitamin 

 G (Bg) in doses of 1 to 5 or 1 to 10 milligrams daily: yeast nucleic 

 acid, guanine hydrochloride, adenine sulfate. Funk's compound of m. p. 

 234° C, betaine hydrochloride, inositol, potassium pyrophosphate, or 

 the non-saponifiable fraction from yeast fat. 



Both Chick and Roscoe (1928) and Williams, Waterman and Gurin 



(1929) pointed out that although vitamin B2 (G) of yeast is more 

 heat stable than vitamin Bi (B), the former is by no means entirely 

 thermostable, especially under alkaline conditions. Chick and Roscoe 



(1930) reported further that vitamin B2 (G) is comparatively stable 

 to prolonged heating when the reaction is acid (pH 5.0 to 3.0), about 

 half remaining after heating for 4 hours at 122° to 124° C. When the 

 reaction was alkaline (pH 8.0 to 10.0), about 30 per cent of the activity 

 was lost in 10 days at room temperature ; 50 per cent upon steaming 

 for 2 hours ; and 75 to 100 per cent upon heating at 122° C. for 4 to 

 5 hours. 



Levene (1930) described a method of separating vitamin G (B2) 



