54 PROTOZOAN PARASITISM 



cannot be a transmitter of the infection either natu- 

 rally or experimentally. The amoebae can be trans- 

 ferred from cat to cat only by rectal injection of the 

 living trophozoites. 



The experimental disease in the guinea pig has 

 been the formation of tumor-like growth of the in- 

 fected wall of the caecum. 



In rats there is the acute colitis corresponding to 

 amoebic dysentery, as well as the development of the 

 non-dysenteric carrier, with minute ulcers of the 

 mucosa of the colon or without any discovered lesion. 



CULTIVATION 



There have been a great many unsuccessful at- 

 tempts to obtain growth of Endamoeba histolytica 

 outside of the animal intestine. Until very recently 

 a good deal of confusion existed as to whether or 

 not it had been done. Certainly a number of reports 

 of its cultivation are erroneous, the amoebae grown 

 being free-living forms accidentally encountered in 

 the material used. 



In the light of subsequent successes it appears that 

 the first cultivation of Endamoeba histolytica, or 

 any true parasitic amoeba, was done by Cutler 

 (1918). Several workers failed to repeat Cutler's 

 success, notably Dobell (1919), and Wenyon, and, 

 consequently, it was taken as other reports had been. 



Following the artificial cultivation of Endamoeba 

 barreti by Barret and Smith (1923), comes the re- 



