VIII, B, 3 Vedder and Williams: Vitamines in Rice 183 



and even when fed as phosphotungstates, without any further 

 treatment. 



Experiment 46. — The hydrolyzed extract obtained from 10 

 kilograms of polishings was completely precipitated by phos- 

 photungstic acid. The precipitate so obtained was extracted 

 by repeated and prolonged shaking with 50 per cent alcohol. 

 The phosphotungstic acid was then removed from this alcoholic 

 solution of the phosphotungstates by barium hydroxide.* A 

 sufficient quantity of this alcoholic extract of phosphotungstates 

 was reserved to feed 4 fowls (group a). The remainder of 

 the solution was carefully neutralized with sulphuric acid, and 

 silver nitrate added until a drop of the clear solution gave a 

 brown precipitate of silver oxide with cold barium hydroxide. 

 The flocculent precipitate so obtained was filtered off and the 

 silver removed by hydrogen sulphide. The filtrate from the 

 silver sulphide so obtained was used to feed 4 fowls (group b). 



The filtrate obtained from this first precipitation with silver 

 nitrate was then rendered distinctly alkaline with baryta. The 

 precipitate so produced was filtered off and the silver removed 

 by hydrogen sulphide, and the filtrate from the silver sulphide 

 was used to feed 4 fowls (group c). The filtrate remaining 

 after these two precipitations by silver nitrate was used to feed 

 4 fowls (group d). 



Sixteen fowls were fed on polished rice, and each group of 

 4 received one of these solutions in a daily dose equivalent to 

 30 grams of polishings, as follows : 



Group a: Four fowls receiving alcoholic extract of total phos- 

 photungstates. All 4 fowls remained well for sixty days. 



Group b: Four fowls receiving silver nitrate precipitate in 

 neutral solution (purine bases). One fowl developed neuritis 

 in thirty-six days and died. A second fowl developed neuritis 

 in forty-six days. A large dose of the solution was given this 

 fowl and the remaining 2 birds. The sick fowl improved in 

 health and ended the experiment on the sixtieth day almost 

 entirely cured, and the other 2 birds remained in health for the 

 full period of sixty days. 



Group c; Four fowls receiving silver nitrate precipitate in 

 alkaline solution (Funk's base). All 4 fowls remained well 

 for sixty days. 



' This method was adopted, because in this way the phosphotungstic acid 

 can be removed without subjecting the solution to a great excess of baryta, 

 as must necessarily be done when the dried precipitate is broken up by 

 barium hydroxide. The use of strong alkaline solutions is to be avoided, 

 as they undoubtedly decompose a part of the protective substances. 



