70 PARASITIC AMCEB.E OF MAN. 



glass culture to the slide can be accomplished either 

 by picking up the cover with forceps and inverting 

 it over the concave centre of the slide, or by pressing 

 the inverted slide upon the cover glass, which adheres 

 to the vaseline ring around the concavity of the slide. 

 The cover is then pressed down around the edges 

 until the vaseline completely seals the culture so as 

 to prevent evaporation of moisture. Ordinarily the 

 moisture of condensation from the solidifying agar 

 and that transferred in inoculating the culture is suffi- 

 cient for growth, but sterile distilled water or any 

 media or reagents can be added with a sterile loop, 

 either at the time of making the culture or later by 

 raising the cover. On these cover-glass cultures 

 amoebae multiply as freely as on Petri plate cultures. 

 The film of agar medium is thin enough to permit the 

 use of a one-twelfth-inch oil immersion objective, and 

 is so nearly transparent that it does not seriously ob- 

 struct the passage of light." 



According to Walker the following are the essen- 

 tial factors in the cultivation of amoebae on artificial 

 media: (1) the consistence should be solid; (2) re- 

 action should be neutral or preferably slightly alka- 

 line; (3) bacteria should be present on which the 

 amoebae can feed; (4) media should be moist and 

 oxygen should be present; (5) a temperature of 20 

 to 25 C. should be maintained. 



