216 DISEASES DUE TO PROTOZOA 



of long standing, and may present work for surgical 

 interference. 



The protozoa leave the body with the feces, which 

 to be disinfected must be well treated with carbolic 

 acid or burned. They should never be allowed to 

 dry, because the entameba may become more resistant 

 in a dry state, due to a curious spore-like stage. This 

 disease is diagnosticated by finding the parasites in 

 the feces or pus, which must be kept at a proper tem- 

 perature during the examination. Some of the material 

 is examined on a warmed plate and kept not lower 

 than 77 F. all the. time. At this degree the peculiar 

 movements of the amebse are noted as a pushing out 

 of a part of the cell wall like a bud. This is the pseudo- 

 pod or false foot. This means of progression enables 

 the organism to penetrate intact mucous surfaces and 

 pass through sand filters impermeable for bacteria. 



The Entameba histolytica is an irregularly shaped 

 mass of simple protoplasm with a primitive structure. 

 Its nucleus is usually single in contrast to other amebse. 

 It measures up to 6 -J-Q- inch. It moves and embraces its 

 food by the pseudopods. It reproduces by division or 

 by the production of daughter-cells within its body. 

 When these are massed together and held by a cap- 

 sule, it is said to be encysted. When such cysts are 

 taken into the body the intestinal juices probably 

 dissolve the capsule and let the cells go free. Encyst- 

 ment occurs when conditions for life become unfavor- 

 able. Amebae are not killed by cold, but succumb to 

 60 C. or 140 F. in one hour. Acids are unfavorable 

 for the growth. They are cultivated artificially with 

 great difficulty, and are usually combined with bacteria, 



