150 SOME MINUTE ANIMAL PARASITES 



entirely to the intestine, but occur on the mucous 

 membrane of the mouth, in carious teeth, in the 

 lungs, the urinary tract, kidneys, liver, and genital 

 tract. That certain intestinal amoebae are non- 

 pathogenic has already been mentioned, and such 

 members perhaps are best described before the 

 disease-producing forms. 



Entamceba coli (Fig. 30) is a frequent occupant of 

 both the healthy and diseased human intestine, more 



FIG. 30 THREE ASPECTS OF ENTAMCEBA COLI 



., Nucleus; />s.,^pseudopodium, showing clear ectoplasm ; v., 

 vacuole with food debris within 



particularly in the tropics. It is therefore of im- 

 portance, for amoebae, when found in stools, may be 

 indications that the person concerned is suffering 

 from amcebic dysentery, or may merely indicate the 

 presence of relatively harmless amoebae in the bowel. 

 E. coli occurs in the cavity of the large intestine, but 

 it is usually incapable of penetrating the 'mucous 

 membrane of the gut, for its pseudopodia are large 

 and blunt. 



