VITAMIN B {Br) 43 



fraction; decomposition of the vitamin-containing fraction with hydro- 

 chloric acid and reprecipitation with phosphotungstic acid and 5 per 

 cent sulfuric acid; purification of the phosphotungstate by solution in 

 acetone and water and reprecipitation with 5 per cent sulfuric acid ; 

 decomposition of the purified phosphotungstate with barium hydroxide, 

 removal of the barium phosphotungstate and excess sulfuric acid, and 

 acidification of the filtrate with hydrochloric acid; evaporation to dry- 

 ness, and solution in absolute alcohol, then precipitation with platinic 

 chloride. The platinum chloride precipitate contains about 25 per cent 

 of the original vitamin. Then followed decomposition of the platinum 

 precipitate suspended in dilute hydrochloric acid with hydrogen sulfide 

 and repeated fractional crystallization of the chloride by dissolving it 

 in absolute alcohol, adding a small amount of acetone, decanting the 

 solution from the small amount of deposit which forms on the side of 

 the flask and repeating the acetone treatment. These elaborate frac- 

 tional recrystallizations often require months to complete. Another 

 method of treating the decomposed platinum salt was by precipitation 

 with picrolonic acid and treatment of the picrolonate with ether or 

 ethyl acetate and hydrochloric acid. A portion of this substance was 

 transformed into a crystalline double salt with chloride of gold. 



By either method there is finally obtained from 300 kilograms of 

 rice polishings about 100 milligrams of "vitamin-hydrochloride," a 

 crystalline substance which after recrystallization has a melting point 

 of 250° C. (corrected). As judged by protective experiments chiefly 

 on small rice birds known as "bondols" and later occasionally on 

 pigeons, the crystalline substance is an exceedingly potent antineuritic. 

 Complete protection was afiforded by from 1 to 2 parts of the material 

 to one million parts of rice. In commenting on this, attention is called 

 to the fact that the dosage is of the same order of magnitude as that 

 of thyroxine or adrenaline. 



The vitamin hydrochloride before final purification crystallizes into 

 bundles of needles and after purification in small bars joined into 

 rosettes. It is not hygroscopic but dissolves readily in water. It is also 

 readily soluble in methyl alcohol and less readily in ethyl alcohol. A 

 2 per cent aqueous solution gives a scanty precipitate with mercuric 

 chloride, increasing with the addition of sodium acetate, a heavy pre- 

 cipitate with mercuric sulfate in dilute sulfuric acid, a fine black pre- 

 cipitate with iodine-potassium iodide, a thick red precipitate with a 

 solution of bismuth iodide in potassium iodide, and opacity with picric 

 acid. No precipitate is formed with zinc chloride, cadmium chloride, 

 lead acetate, cupric acetate, potassium chromate, potassium thiocyanate, 



