68 PARASITIC AMOEBA OF MAN. 



the failure of so-called parasitic amoebse to develop 

 upon culture media at the body temperature is addi- 

 tional proof of the free-living nature of the amoebse 

 which have been cultivated. However, even free- 

 living amoebae may be cultivated at 37 C. without 

 much difficulty. 



A simple and easy method of securing cultures of 

 amoeba? from feces consists in mixing with the ma- 

 terial to be examined an emulsion of the bacterium 

 to be used in symbiosis and streaking this mixture 

 across the surface of the culture medium contained 

 in Petri dishes. 



To secure a culture of a single amoeba in symbiosis 

 with bacteria the culture plates are carefully ex- 

 amined and a single amoeba is located. In order to 

 remove this organism from the plate, Musgrave's 

 method may be employed, which consists in lowering 

 a low power objective until it just touches the medium 

 where the amoeba lies, and then quickly raising it, 

 thus picking up the amoeba, which can then be trans- 

 ferred to a new plate ; or a single organism is located 

 and with a fine glass capillary pipette is removed 

 from the surface of the plate, and placed upon new 

 media. Walker marks the situation of the single 

 amoeba with a wax pencil on the bottom of the Petri 

 dish, using a V-shape mark, the apex of which just 

 encloses the amoeba, the arms of the V extending 



