60 PARASITIC AMCEBJS OF MAN. 



amoeba? from the feces of man either in health or 

 disease, but in temperate regions, where free-living 

 forms are comparatively rare, it is but seldom that 

 one is successful in cultivating such organisms from 

 the feces. Numerous attempts have been made to 

 cultivate amoebae at this laboratory from patients 

 whose stools contained Entamoeba histolytica and En- 

 tamoeba tetragena, as well as Entamoeba coli, and in 

 not a single instance have cultures been obtained 

 of any amoebae, in spite of the fact that the same 

 methods were used that had proven successful in the 

 Philippine Islands, and that the same observers had 

 secured amoeba cultures in those Islands without 

 trouble. However, it is not difficult to explain these 

 results. In the Philippines almost all drinking water, 

 as well as salad vegetables, are infested with free- 

 living amoebae, and it naturally follows that such forms 

 are continually passing through the intestinal canal 

 of man, and may be obtained upon suitable culture 

 media from the infected feces ; in Washington, on the 

 other hand, free-living species of amoebae are com- 

 paratively rare, and it follows that attempts to culti- 

 vate amoebae from the feces generally result in failure, 

 as the parasitic species do not develop upon the cul- 

 ture media at present in use. To my mind the failure 

 to cultivate amoebae from dysentery patients in certain 

 regions, although the same methods which are sue- 



