AMCEBJE OF THE INTESTINAL TRACT. 191 



the intestines, to be excreted in a condition still 

 capable of development." 



The observations of Werner regarding Amoeba 

 Umax are probably true as all the cultivated amoeba? 

 which I have observed have shown a contractile 

 vacuole which is not present in any parasitic amoeba in 

 man. The same negative results were obtained by 

 Hartmann and Prowazek, as well as Werner, in the 

 cultivation of Entamceba Mstolytica, so that I believe 

 that it is still doubtful if either of these amoebae has 

 ever been cultivated. 



RELATION TO DISEASE. The experiments of 

 Viereck, Hartmann and Prowazek, and Werner, 

 prove conclusively that Entamaeba tetragena pro- 

 duces a form of amoebic dysentery, but Hartmann 

 believes that it is not as pathogenic for cats as Enta- 

 mceba Mstolytica. The incubation period in his ex- 

 periments varied between 8 and 10 days, and the in- 

 fection lasted from three weeks to a month. Upon 

 autopsy the cats presented typical lesions of amoebic 

 dysentery and the amoeba was found in sections of 

 the intestine. 



Werner, at the Sailors' Hospital in Hamburg, 

 worked with five strains of Entamceba tetragena, 

 only three of which he found to be pathogenic. One 

 of these was still infective after five, one after three, 



