ETIOLOGY OF BERIBERI. 409 



iologically proper diet, they usually prevent the development of 

 the symptoms of the disease. In some instances, however, even 

 when these substances are constituents of the diet, when the 

 diet is without variation and composed of very few articles, and 

 the individual suffers from loss of appetite and the assimilative 

 functions appear to be poor and he loses markedly in weight, 

 symptoms of beriberi may develop in such individuals. However, 

 such symptoms may be dispersed by causing a variation in the 

 diet by the addition of other nutritious substances to it. It 

 is also evident from our experiments that the disease is 

 certainly not an infectious one in the sense which we usually 

 employ this term. The rigid isolation of the prisoners under- 

 going the test would seem to exclude the possibility of the 

 introduction of an infectious agent through any other individual 

 or by the introduction of any article. And although the indi- 

 viduals of Groups I, II, and III all mingled freely together, 

 there was no tendency of the disease to spread in Groups I and 

 III. It is also noteworthy that the cases of beriberi developed 

 under the most favorable hygienic conditions with exception in 

 regard to diet. It is not probable that the infection could have 

 been introduced with the food, since this was all freshly cooked, 

 and at a temperature at which only a spore-bearing organism 

 would survive. The food was also eaten a very short time after 

 being cooked. Moreover, if the infection had been introduced 

 with the food, the incidence of the disease should have been the 

 same in all of the groups, which it was not. No fermentation of 

 the rice employed occurred either before or after it was cooked, 

 so that it would appear that the action of such bacteria as have 

 been described by Kohlbriigge *''■ and by Breaudat ■*■ could be 

 excluded. It has been suggested that a diet of white rice pre- 

 disposes to the disease, since it furnishes a better medium for 

 the development of the specific organism which resides in the 

 intestine of the host, and that the red rice or extract of polish- 

 ings forms a preventive for the development of such a specific 

 organism. There is no definite evidence of such an hypothesis 

 and, moreover, the results obtained in our experiment would 

 argue against it, since in two instances, at least (Nos. 1 and 13), 

 distinct symptoms of beriberi were present in individuals who 

 had received these substances in the diet. It can not be claimed 

 with reason that the resistance of the individuals having 

 been lowered by weakness and loss of weight, the specific or- 

 ganism residing in the intestine of the individual was able to 



"* Loc. cit. " Loc. cit. 



