ETIOLOGY OP BERIBERI. 255 



Four fowls were then fed on polished rice giving them a daily dose 

 of 10 cubic centimeters of this cloudy fluid representing the substances, 

 other than fat, dissolved by alcohol from 10 grams of polishings. Of 

 these four fowls, one died on the 69th day, probably of avian diphtheria, 

 without ever showing any signs of neuritis, and the other three remained 

 in good health until the 70th day, when the experiment was discontinued. 



Therefore, the neuritis-preventing principle is soluble in cold 95 per 

 cent alcohol. 



Since the neuritis-preventing principle of rice polishings is soluble in 

 both cold water and cold alcohol, it is apparent that by combining 

 these two solvents the resultant extract can be much simplified, because 

 certain substances derived from the polishings are soluble in alcohol 

 but not in water, and vice versa. This is the principle that was adopted 

 in the following experiment. 



Experiment 3. — The cloudy extract used in experiment 2 was filtered 

 until a perfectly clear yellowish fluid was obtained. This fluid con- 

 tained only those substances extracted from rice polishings by alcohol 

 and soluble both in alcohol and water. 



Pour fowls were fed on polished rice, with a daily dose of 10 cubic 

 centimeters of this clear extract. These four fowls lived for 70 days 

 . in good health, thereby proving that this extract i^s^ capable of prevent- 

 ing neuritis, since in our experience fowls fed on polished rice alone 

 developed neuritiscin about 30 days on the average. 



Through the courtesy of the Bureau of Science * the extracts used 

 in these experiments were analyzed with the following result : 



The precipitate which had not been removed from the extract used in 

 experiment 2, but had been removed from the extract given to fowls in 

 experiment 3, contained 0.000033 per cent phosphorus pentoxide and 

 0.00116 per cent nitrogen. 



The clear filtrate given to fowls in experiment 3, contained 0.00165 

 per cent phosphorus pentoxide and 0.0406 per cent nitrogen. 



It will readily be seen that the fowls in exiDeriment 2 received the 

 sum of the phosphorus and nitrogenous substances contained in the 

 precipitate and filtrate. In both experiments the amount of phosphorus 

 received was so small as to be negligible. One hundred cubic centimeters 

 of the filtrate used in experiment 3 contained only 1.6 milligTams of 

 phosphorus pentoxide and since the daily dose given the fowls was 10 

 cubic centimeters they received 0.16 milligTam jihosphorus pentoxide 

 daily, whereas if they had been fed 10 grams of rice polishings they 

 would have received from 200 to 500 milligrams of phosphorus pen- 

 toxide. The total amount of phosphorus pentoxide in rice polishings 



* We hereby desire to express our obligation to Mr. Harry D. Gibbs, Dr. A. P. 

 West, and Mr. R. R. Williams, chemists of the Bureau of Science, who independ- 

 ently performed these analyses. 



