ETIOLOGY OF BERIBERI. 257 



removed and the apparatus refilled with distilled water. This process 

 was repeated three times, and the combined fluid removed from the 

 outside of the bag, containing all the diffusate, was brought to 1,000 

 cubic centimeters, while the extract remaining inside the bag, the 

 dialysate, was diluted likewise to 1,000 cubic centimeters. 



Pour fowls were now fed on polished rice plus 10 cubic centimeters 

 daily of the dialysate and four other fowls were also fed on polished 

 rice plus 10 cubic centimeters daily of the diffusate, with the following 

 results. 



Group 1 (four fowls receiving polished rice plus dialysate) : One 

 fowl died of inanition in 23 days. One fowl developed neuritis in 38 

 days, one in 43 days and one in 52 days.^ 



Group 2 (four fowls receiving rice plus diffusate) : All four remained 

 well at the end of 70 days. 



Therefore, it is apparent that the neuritis-preventing substance is 

 capable of dialyzing through a parchment membrane. 



Analysis of this diffusate showed that it contained only 0.02 per cent 

 nitrogen so that at least half of the nitrogen originally present must 

 have been combined in some other fomi than proteid, because there 

 could be no proteid present in the diffusate. 



The results of this last experiment are very far-reaching in their 

 importance. Since the neuritis-preventing substance can dialyze through 

 a parchment membrane it must belong to the class of crystalloids, and 

 all colloidal substances, including proteids, gums, starches, dextrins, 

 and many other substances, may be eliminated from further considera- 

 tion. Probably enzymes also can be excluded. (6) 



CONCLUSIONS. 



1. Polyneuritis gallinarum is not prevented by adding to a diet of 

 polished rice any of the following substances; potassimn phosphate, 

 potassium citrate, potassiimi carbonate, potassium chloride, magnesium 

 phosphate, phytin, phosphoric acid, or phosphoric acid combined with 

 potassium chloride. 



2. The neuritis-preventing substance in rice polishings is soluble 

 in cold water and in cold alcohol. 



3. Polyneuritis gallinarum may be prevented by means of an extract 

 of rice polishings containing only those substances soluble in cold water 



^ The rather long "incubation period" for the neuritis in this group we 

 believe to be due to the fact that the first supply of dialysate fed to these fowls 

 was prepared not in a bag (as described above), but in a bottle with the mouth 

 covered with parchment. The small dialyzing surface probably rendered dialysis 

 slow, allowing a part of the neuritis-preventing substance to remain behind and 

 thereby delaying the onset of the disease. 



