ETIOLOGY OF BERIBERI. 47 



these three acids failed to prevent neuritis and since a neutral 

 extract added to polished rice did prevent the disease, it is quite 

 obvious that acidity per ae can be of no importance. 



The following? points are of interest with reference to Kohl- 

 brugge's view that a culture of his rice bacillus, obtained from 

 fermented rice, was capable of producing neuritis of fowls in 

 four or five days. 



Shiga (9), in endeavoring to test the validity of the intoxica- 

 tion theory, performed the following experiment: He fermented 

 an undermined rice in the incubator for about a week and fed 

 fowls on this fermented material, but they remained healthy 

 for two hundred days, when the experiment was discontinued. 

 We have repeated this experiment with the same result. We 

 have, also, fed fowls on a highly milled rice, fermented in a sim- 

 ilar way, and have found that these fowls do not develop neu- 

 ritis any sooner than fowls fed on the same rice when perfectly 

 fresh and dry. These facts seem to us absolutely to disprove 

 Kohlbrugge's theory. 



On comparing the two rations used in Bilibid prison (Tables 

 IV and V) , it will be seen that in the latter dietary (which led 

 to the disappearance of beriberi) one of the most obvious changes 

 was the very great increase in the amount of onions prescribed. 

 Onions are very rich in amido-nitrogen compounds, and the oil 

 of onions is composed almost entirely of allyl sulphide (C;jH.,)2S. 

 In order to determine whether the increased consumption of 

 onions could have been responsible for the disappearance of beri- 

 beri, Experiment 17 was performed. Two kilograms of onions 

 were ground up finely in a meat cutter, mixed with 2 liters of 

 water, and allowed to macerate for twenty-four hours in the 

 ice-box. The mixture was then filtered. The clear filtrate con- 

 tained the greater bulk of the onions, very little solid matter 

 being left on the filter. 



Experiment 17. — Four fowls were fed on polished rice plus a 

 daily dose of 10 cubic centimeters of extract of onions. 



One fowl developed neuritis in twenty-one days, 1 in twenty- 

 two days and 1 in forty-three days, after which the experiment 

 was discontinued. 



Since the neuritis-preventing substance is soluble in water, 

 it should have been contained in this extract if it were originally 

 present in the onions. As the experiment was negative, we are 

 forced to conclude that onions will not prevent polyneuritis 

 gallinarum, and therefore are not likely to prevent beriberi. 



