178 The Philippine Journal of Science ms 



The method of extracting by alcohol was originally adopted 

 by us because it produced an extract that was chemically much 

 simpler than that obtained by other methods and thus afforded a 

 better opportunity for identifying the protective substances, and 

 we have continued to use this method in preparing extracts for 

 the treatment of beriberi cases in spite of the disadvantage of the 

 comparative insolubility of the protective substances in alcohol, 

 because we have found that extracts obtained in several other 

 ways are distinctly poisonous, a fact to which we shall refer 

 again later. We have found, however, that a more powerful 

 extract may be obtained by using alcohol of only 90 per cent 

 strength, or by using alcohol at a temperature of from 60° to 70°. 



In a previous paper (3) we stated that sodium hydroxide de- 

 stroyed the neuritis-preventing substance. We have also found 

 that it is destroyed by ammonia. 



Experiment UO. — In the course of our experiments to deter- 

 mine the solubility of the protective substances in ether, extract 

 of rice polishings which had previously been tested and found 

 active was rendered strongly alkaline with ammonia, and was 

 then extracted by shaking with ether. The ether was then 

 removed and evaporated at a low temperature and the residue 

 diluted with water. 



(a) Four fowls were fed on polished rice, and in addition were 

 given daily a quantity of the substances extracted by the ether, 

 equivalent to 10 grams of polishings. One fowl developed neu- 

 ritis in twenty-eight days and one in twenty-nine days, when the 

 experiment was discontinued. 



(6) Four fowls were fed on polished rice, and in addition were 

 given daily 10 cubic centimeters of the aqueous extract of rice 

 polishings remaining after the extraction with ether. One fowl 

 developed neuritis in thirty-eight days and one in forty-five days, 

 when the experiment was discontinued. 



Since this extract originally protected fowls completely, while, 

 after treatment with ammonia, both the ether extract and the 

 residual portion failed to protect, it appears that the protective 

 substances were destroyed by the ammonia. The significance 

 of this fact will appear later in discussing the action of barium 

 hydroxide. 



In one of his papers (6) Funk stated that while allantoin had 

 no effect in curing pigeons that had already developed neuritis, 

 it appeared to prolong the life of the birds. As we had found 

 (see experiment 46) that the administration of a mixture of 



