ETIOLOGY OF BERIBERI. 403 



beans as a preventive against beriberi in the rations of native troops, 

 native prisoners, and others. Probably in actual practice the ordinary 

 white bean may be even more efficacious than mongos, because beans 

 are more savoiy and are more desired as an article of diet by all classes 

 of men. This point must be borne in mind when prescribing for natives 

 a diet consisting largely of rice. If the natives do not happen to care 

 for mongos, or the other articles introduced into the ration for the purpose 

 of preventing beriberi, they will not eat them, but will live on an almost 

 exclusive diet of rice; but the man, native or white, who does not relish 

 well cooked beans is hard to find, and it is believed that they would be 

 generally eaten by persons who would'refuse to eat mongos. 



It is also quite possible that this observation will be of further as- 

 sistance in identifying the beriberi-preventing principle. . Extracts of 

 beans and of rice polishings doubtless contain many substances peculiar 

 to themselves, but we may find some substance, or a few substances, 

 . common to both of these extracts. If this should occur, it is probable 

 that the neuritis-preventing principle will be found, or at least the search 

 for it will be restricted to very naiTow limits. 



We have also performed some experiments in the course of which we 

 evaporated the extract of rice polishings to drjmess in a water bath at 

 100°C. This necessitated prolonged heating at this temperature and 

 we found that the extracts so prepared had lost their efficacy. It has 

 long been known that even a brief exposure to a temperature of 120°C. 

 destroyed the neuritis-preventing substance and it is now shown that 

 prolonged exposure to a temperature of 100°C. vdll also produce the 

 same effect. It is possible that this is the reason why our decoction of 

 mongos lost some of its power, and we would recommend, therefore, 

 that no extract supposed to contain the neuritis-preventing principle 

 should be boiled for more than one hour. 



CONCLUSIONS. 



We have made some progress in the identification of the neuritis- 

 preventing substance contained in the extract of rice polishings prepared 

 by the method described in our first paper. Of 1.34 per cent total 

 solids contained in this extract, 0.03 per cent was ash. This we believe 

 to be negligible since it consists entirely of inorganic constituents, chiefly 

 of lime, magnesia, and potassium carbonate. We have tried salts of 

 calcium, magnesium, and potassium and found them wanting. Nitro- 

 genous matter comprises 0.04 per cent of the total solids. Of this only 

 0.02 per cent was present in the diffusate, which has been shown to 

 contain the neuritis-preventing principle, and the remaining 0.03 per cent 

 can be eliminated because it remained in the dialysate which failed to 

 prevent neuritis. The 0.88 per cent sucrose is of no importance. Com- 

 bining these unimportant substances and subtracting them from the 1.34 



