46 CHAMBERLAIN, VEDDER, AND WILLIAMS. 



polishings. Two fowls developed neuritis on the fortieth <day 

 and 1 developed neuritis on the forty-first day. The fourth 

 fowl remained well for fifty days when he was released. 



It is, therefore, obvious that 2.5 cubic centimeters of our ex- 

 tract, equivalent to 2.5 grams of the rice polishings, is insufficient 

 to protect the majority of fowls as long as fifty days, although de- 

 laying the onset of symptoms of neuritis for about ten days, 

 but that 5 cubic centimeters is sufficient to afi'ord complete pro- 

 tection for at least fifty days. The fact that a definite dose of 

 this extract is necessary to protect fowls, while a smaller dose 

 delays the onset of the disease, is an additional argument in 

 favor of the assumption that polyneuritis gallinarum is a disease 

 due to the absence of some essential nutritive principle. This 

 work with reduced doses of extract agrees quantitatively with 

 the results obtained by Fraser and Stanton, who found that 5 

 grams of rice polishings were sufficient to prevent neuritis when 

 fowls were subsisting on polished rice. 



We have long been convinced that polyneuritis gallinarum is 

 due to a nutritive deficiency, but apparently some others are not, 

 since Kohlbrugge has recently published an article maintaining 

 that this disease is caused by the acid produced during the fer- 

 mentation of rice which results from the action of a number of 

 acid-producing bacteria contained in the rice itself. There are 

 many possible criticisms of Kohlbrugge's work, but we will limit 

 ourselves to the following: 



Kohlbrugge states that he has produced beriberi in fowls in 

 four or five days by feeding polished rice mixed with agar cul- 

 tures of the acid-producing bacteria isolated from rice. How- 

 ever, he did not demonstrate the existence of nerve degenerations, 

 and gave few details of his experiment. From what we know 

 of beriberi and polyneuritis gallinarum it seems to us impossible 

 that he could produce this disease in four or five days, and it 

 appears that his fowls must have died of toxssmia or infection, 

 and not of beriberi. He further states that the disease is pre- 

 vented by large amounts of acid in the food, maintaining that 

 excessive acidity inhibits the growth of the bacteria. Thus rice 

 polishings, beans, etc., are preventive because they contain a 

 great amount of acid. This is certainly incorrect, because we 

 have prevented neuritis in fowls by means of an extract of rice 

 polishings that had been neutralized with sodium carbonate. It 

 may be possible that some particular acid, or its salt, is the 

 neuritis-preventing substance, but we have tried phosphoric 

 acid, sulphuric acid, and lime juice with negative results. Since 



