VIII. B, 4 Walker and Sellards: Entamcebic Dysentery 257 



portion of the experimental animals (cat, dog, monkey) by 

 feeding or injecting rectally dysenteric stools or so-called liver- 

 abscess pus containing entamoebse. In some cases these ex- 

 periments have been controlled by feeding to another animal 

 cultures of all of the bacteria that could be grown from the 

 infectious material on ordinary culture media. Dysentery has 

 also been produced experimentally in animals by rectal,^ and in 

 one case by intravenous,* injections of pus from liver abscesses 

 containing entamoebse, but free from bacteria cultivable on 

 ordinary culture media. Finally, several investigators " state 

 that they have produced a disease in animals and, in one case, in 

 man having the clinical symptoms of entamcebic dysentery, with 

 entamoeba in the stools, and exhibiting the characteristic lesions 

 in the intestine at necropsy, by feeding or injecting rectally "pure 

 mixed cultures" of amoebse and nonpathogenic bacteria, which 

 had been isolated not only from stools of dysenteric patients, but 

 from water and other nonparasitic sources. 



Certain of these experimental infections furnish considerable 

 support to the belief in the etiologic relationship of amoeboid 

 organisms to endemic tropical dysentery, but most of the experi- 

 ments are open to criticism. The infection experiments with 

 dysenteric stools, uncontrolled, are of little more value than 

 clinical observations; since not only the entamoebse, but all of 

 the other microorganisms contained in the fseces were fed or 

 injected in these experiments. The infections with dysenteric 

 stools, controlled by feeding other animals all of the bacteria 

 cultivable from the stools on ordinary media, and with liver- 

 abscess pus free from bacteria cultivable on ordinary culture 

 media, are more convincing ; but they would not exclude bacteria 

 cultivable on special media — or under anaerobic conditions — or 

 the filterable viruses. The work of those authors who obtained 

 dysentery in experimental animals following the feeding of 

 "pure mixed cultures" of amoebae and nonpathogenic bacteria 

 would appear to obviate all criticism. But these and many 

 of the other experiments are open to a more serious criticism; 

 namely, that the species of amoeboid organism fed to, and re- 

 covered from, the experimental animal have not been accurately 

 determined. The truth of this statement will be evident to 



' Kruse and Pasquale (1903), Strong and Musgrave (1900). 

 'Gauducheau (1906). 



"Kartulis (1891), Musgrave and Clegg (1904), Williams and Gurley 

 (1909). 



