ETIOLOGY OF BERIBERI. 273 



To summarize from the evidence, it appears more likely that a parasite 

 will be found to be the spreader of the disease, which makes it more 

 probable that the actual cause will be found to be a protozoon than that 

 it is due to diet, which, however, may be a predisposing cause, especially if 

 the nutritive value of the food is low, or the proportions wronpf. 



Shibayama "'■ also holds a somewhat similar view: 



It is therefore not unreasonable to assume that the microorganisms of 

 beriberi are only present in the Orient and, ^iven a predisposing cause, 

 are capable of causing: the disease, whereas in the West beriberi does not 

 appear, owinp to the absence of the infecting orp:anisms, although the same 

 favorable predisposing cause may be present. 



Marchoux '" (also writing in 1910) believes that a diet of 

 white rice furnishes in the intestine a favorable culture-medium 

 for the development of the specific organism of beriberi and that 

 the addition of rice-bran to the diet without doubt renders the 

 condition in the intestine unfavorable for the development of 

 this organism. 



However, none of these authors has brought forward any 

 definite proof that beriberi is caused by a specific microorganism 

 and, although numerous other investigators have described either 

 various species of bacteria or of protozoa as the cause of the 

 disease, yet to-day not one of these claims has been substan- 

 tiated from a scientific standpoint. Obviously, however, the 

 fact that the specific microorganism for the disease has not been 

 discovered is not a final argument against its infectious nature, 

 for the causative organism in many diseases of an undoubted 

 infectious nature has been sought for as diligently and in a man- 

 ner equally as unsuccessful as in the case of beriberi. The 

 result of the experiments of de Haan and Grijns ^'' failing to 

 demonstrate the presence of antibodies in the blood serum or 

 various organisms of beriberi patients or of fowls suffering with 

 polyneuritis, as well as that of the experiments of Shiga and 

 Kusama,"^ who failed to obtain the reaction of deflection of the 

 complement in the serum of beriberi cases, also does not ex- 

 clude definitely the possibility of the disease being an infectious 

 one. 



However, if by scientifically controlled and accurate experi- 

 ments we can produce the disease and exclude the influence of a 

 living specific microorganism, the infectious theory of its origin 



" Loc. cit. 



" Loc. cit. 



" Genees. Tyds. v. Ned. Ind. (1909), 49. 



"Beihefte z. Arch. f. Schiffs- «. Trop.-Hyg. (1911), 15, 61. 



