192 PARASITIC AMGEBJE OF MAN. 



and one after one passage through cats, but they all 

 lost their virulence after repeated passage. The in- 

 cubation period in these animals varied from 5 to 12 

 days, the average being 7^ days. The duration 

 of the disease varied from 8 to 25 days, the 

 average being 17 days. He did not find any marked 

 differences between the lesions produced by tetragena 

 and Mstolytica and he does not believe that the evi- 

 dence supports the idea that tetragena is less patho- 

 genic than histolytica. 



In one case Werner observed abscess of the liver 

 in a cat following infection with Entamceba tetragena. 

 Regarding this case he says: 



" A cat that had been infected per rectum with 

 a strain of tetragena from the Far East sickened 

 after five days' incubation, and had dysentery symp- 

 toms, amoeba* being found in the stools, which con- 

 tained blood and mucus. After being ill for 12 

 days it died, and in the lower portion of the colon 

 were found ulcers. In the right lobe of the liver 

 near the anterior surface was found an abscess as 

 large as a hazel-nut. This contained sticky pus, in 

 which amoebaB of the tetragena type were found." 



I have had no personal experience with the ex- 

 perimental production of dysentery in cats with Enta- 



