VIII, B, 4 Walker and Sellards: Entamoebic Dysentery 259 



these diseases to a remarkable extent. The successful transmis- 

 sion of malaria by the anopheles mosquito from man to man 

 (Sambon and Low, 1902) and the experimental infection of man 

 with yellow fever by the stegomyia mosquito (Reed, Carroll, and 

 Agramonte, 1901) are two notable examples of the solution of 

 obscure etiologic and epidemiologic problems through human 

 experimentation and of the vast benefit to mankind that has 

 resulted from such experiments. 



Entamoebic dysentery, while it does not cause the spectacular 

 epidemics of some other infectious diseases, is of universal dis- 

 tribution in the Tropics and subtropics, and every year causes a 

 large amount of sickness and death. The study of this disease 

 by clinical and pathological methods and by experiments upon 

 animals has led to no definite agreement upon the etiology or the 

 endemiology of this disease. Therefore, an attempt has been 

 made to determine once for all the specific amoeboid organisms, if 

 any, concerned in the production of endemic tropical dysentery 

 by a series of carefully conducted experiments upon volunteers. 



These experiments have been carried on within the endemic 

 region at Manila, where material has been available and where 

 the conditions for this investigation have been found to be 

 as favorable as possible. Men at Bilibid Prison, who had long 

 sentences to serve, who had been under observation for years 

 in the prison, and who eat cooked food and drink distilled water 

 exclusively, have been available for the experiments. Moreover, 

 these men had been examined for intestinal parasites, including 

 entamcebse, on admission to the prison, and those who were in- 

 fected had received treatment. Consequently, the men have been 

 under complete control, and the existence or possibility of natural 

 infections with amoeboid organisms have been reduced to a 

 minimum. 



All of the men to whom pathogenic amoeboid organisms have 

 been fed were volunteers. The nature of the experiment and the 

 possibility of the development of dysentery as a result of the 

 experiment were carefully explained to each of these men in 

 his native dialect, and each man signed an agreement to the con- 

 ditions of the experiment written in the native language. No 

 promise of immunity to prison discipline, or commutation of 

 sentence, and no financial inducements were employed to influence 

 a man to volunteer, in accord with the authority under which this 

 work was carried on. 



