52 The Philippine Journal of Science i9i6 



The earlier surmise of Funk that the vitamines are purine 

 er pyrimidine derivatives, on the other hand, does not appear 

 to agree with the known facts above cited. It is supported by 

 the semicurative properties of allantoin and other purine and 

 pyrimidine bodies, which is, however, largely offset by the sim- 

 ilar though less-marked property of nicotinic acid. No doubt 

 the conception of the vitamines as necessary foodstuffs for the 

 elaboration of certain tissue constituents had weight with Funk 

 in this surmise. Experience with human beriberi, however, 

 throws much doubt on the truth of this conception, the evidence 

 against which is presented elsewhere.^* 



EXPERIMENTAL PART 

 METHOD OF SEPARATION OP THE VITAMINE OF RICE POLISHINGS 



Twenty-five kilograms of selected, finely ground, light-colored 

 rice polishings are allowed to macerate with occasional stirring 

 for from twelve to twenty-four hours in a mixture of 75 liters 

 of 95 per cent alcohol and 5 liters of concentrated hydrochloric 

 acid. The mass is then pressed out at a pressure of about 

 1,000 pounds to the square inch. The collected liquid amounts 

 to from 60 to 65 liters. It is evaporated in a copper still at a 

 pressure of from 10 to 12 centimeters of mercury to a volume 

 of about 3 liters. The concentration requires about seven 

 hours. The temperature should not rise above 50°. The con- 

 centrated extract separates into layers of fat and aqueous liquid. 

 The aqueous extract is separated from the fat while still warm 

 and is filtered from a copious black sediment, which after being 

 washed is discarded with the fat. The filtered extract and 

 washings are further concentrated in glass under a good vacuum 

 to 2 liters. 



Phosphotungstic acid is added gradually till permanent pre- 

 cipitation is complete. An excess must be avoided. Some sam- 

 ples of phosphotungstic acid were encountered which produced 

 temporary precipitates which later redissolved when concen- 

 trated solutions were added to an extract already completely 

 precipitated. Therefore care should be taken that the further 

 precipitation is permanent. After standing overnight, the pre- 

 cipitated phosphotungstates are collected and thoroughly washed 

 with 5 per cent sulphuric acid till the washings show only 

 traces of chlorides. When thoroughly air-dried the phospho- 

 tungstates so produced weigh from 2,200 to 2,500 grams, com- 



" Williams and Johnston, This Journal, Sec. B (1915), 10, 337. 



