ETIOLOGY OF BERIBERI. 397 



series of experiments aud that further work would be performed to 

 confirm the observations. 



We are now able to state that these results have been fully confirmed. 

 We have prepared this extract on a large number of occasions, and from 

 five different lots of rice polishings. The quantitative analyses of these 

 several extracts have varied slightly from that given above, as might 

 be expected, but there has been no essential difference. 



At different times we have fed seven groups, each of which consisted 

 of four fowls, on polished rice combined with this extract in its pure 

 form or after it had been modified by dialysis or by fermentation, with 

 the following results : 



Group 1. — Four fowls remained well at the end of seventy days. 



Group 2. — Four fowls remained well at the end of seventy days. 



Group 3. — Four fowls remained well at the end of one hundred days. 



Group 4. — Three fowls remained well at the end of fifty days and one 

 died, apparently of starvation, without evidence of neuritis. 



Group 5. — Four fowls remained well at the end of sixty days. 



Group 6. — Four fowls remained well at the end of fifty-four days. 



Group 7. — Four fowls remained well at the end of thirty-nine days. 



This makes a total of twenty-seven fowls that we have maintained 

 in health on a diet of polished rice by the addition of this extract. This 

 same rice repeatedly caused the development of neuritis within thirty 

 days in fowls of our other experiments. Fraser and Stanton report a 

 number of experiments in which the fowls were kept for only thirty-five 

 days, a period within which neuritis ordinarily declares itself, but we 

 have kept our birds from fifty to one hundred days. We have now been 

 studying polyneuritis gallinarum for more than eighteen months and 

 after observing a large number of fowls we think it is quite certain that 

 no group of twenty-seven fowls could be maintained on a diet of polished 

 rice for thirty days without the development of a single case of neuritis, 

 unless they received some neuritis-preventing substance in addition to 

 the rice. When this period is prolonged to fifty, seventy, and one hun- 

 dred days, the results become conclusive. 



Therefore, we regard it as proved that our extract of rice polishings 

 prepared as described in our previous paper contains a neiiritis-preventing 

 principle. 



By the same reasoning we regard it as proved that this neuritis-prevent- 

 ing substance- is dialyzable. The four fowls that were kept one hundred 

 days were fed on polished rice combined with the diffusate obtained from 

 this extract. 



In this connection it is interesting to note that after our first paper 

 had gone to press we received the last communication published by 

 Frazer and Stanton (3) in which they showed that the dialysate was in- 

 capable of protecting fowls from neuritis, thus independently confirming 



