VIII, B, 4 Walker and Sellards: Entamoebic Dysentery 263 



the same material, but who did become parasitized with the enta- 

 moebje. Furthermore, it has been found that not all of the in- 

 dividuals parasitized with the presumably pathogenic entamoebse 

 developed dysentery; that is, some of them become "contact 

 carriers." A number of feeding experiments have been made 

 with entamcebse from such "carriers" who had not, and have 

 not subsequently, developed dysentery. In several cases the enta- 

 moebas have been passed successively through two such "carriers" 

 to a third man, in some of whom dysentery was produced. By 

 these controls the attempt has been made to eliminate the possible 

 etiologic action of the bacteria or other microorganisms asso- 

 ciated with the pathogenic entamoebse. 



This large series of experimental infections has been conducted 

 to a successful finish with a minimum of discomfort and without 

 danger to the men. By these experiments it is believed that the 

 specific entamceba concerned in the etiology of endemic tropical 

 dysentery has been definitely determined, the endemiology of this 

 disease elucidated, and information obtained of the greatest value 

 for the diagnosis, treatment, and prophylaxis of this important 

 tropical disease. 



PART II. FEEDING EXPERIMENTS WITH CULTURES OF AMCEB^ 



By Ernest Linwood Walker and Andrew Watson Sellards 



This series of experiments was undertaken to obtain cumulative 

 evidence refuting the conclusions of several authors that amoebae 

 cultivated from water and other nonparasitic sources and from 

 dysenteric stools are capable of living parasitically and, in cer- 

 tain cases, of producing dysenteric symptoms and ulcerative 

 lesions in the intestine of man and other animals. 



Kartulis (1891) reports the production of dysentery in 1 cat by rectal 

 injections of pure cultures of amoebae, isolated from a liver abscess, and in 

 2 cats with impure cultures of amoebae, isolated from a dysenteric stool, 

 grown on a straw-infusion medium. These experiments were controlled 

 by feeding and injection experiments with the bacteria isolated from 

 dysenteric stools, which were followed by negative results. 



Celli and Fiocca (1894) cultivated 6 species of amoebae from the intestine 

 of man, which they identified with species which they had cultivated from 

 water and soil. No experiments were made to test the pathogenicity of 

 the species. 



Musgrave and Clegg (1904) state that they produced dysentery in 

 monkeys, and in one case in man, having the symptoms and lesions of 

 entamoebic dysentery, with amoebae in the stools, by feeding, or injecting 

 subcutaneously, "pure mixed cultures" of amoebae and harmless bacteria, 

 which had been cultivated not only from dysenteric stools but also from 



