AMCKBA PROTEUS VS. ENDAMCEBA COLI 



tively high and constant (37°C.). Peristalsis, which 

 transports the intestinal contents towards the rectum, 

 tends to carry the amoebae out of the body, just as cur- 

 rents of water may transport Amooha proteus from place 

 to place. On the whole the environment of Endamocba 

 coli is much more constant than that of Amoeba proteus, 

 but the important points are that each species maintains 

 itself successfully in its own particular environment and 

 that there are no fundamental differences between these 

 environments. If either species is transferred to the en- 

 vironment of the other it is very quickly killed, but both 

 species may be grown in artificial cultures. Amoeba pro- 

 teus may be grown in the laboratory in a flat dish con- 

 taining pond weed immersed in water. The cultivation of 

 Endamocba coli requires more care, but has recently been 

 accomplished by several investigators. The culture me- 

 dium consists of hens' eggs and Ringer's solution and is 

 very easily prepared. Specimens of Endamocba coli are 

 placed in the culture fluid and incubated at 37°C. Because 

 of the rapid growth of bacteria new cultures must be 

 made and inoculated at frequent intervals (approximately 

 twenty-four to forty-eight hours). 



The processes of reproduction are not fully known in 

 either Amoeba proteus or Endamocba coli. We know that 

 both of them multiply asexually by binary division and 

 that this division is by a sort of mitosis but without the 

 dissolution of the nuclear membrane. Sexual phenomena 

 may be exhibited, but none has yet been established with 

 certainty. Cysts have been described in the life cycle of 

 Amoeba proteus, but appear to be of uncommon occur- 



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