66 PARASITIC AMCEB^E OF MAN. 



as doubtful as one can hardly draw conclusions re- 

 garding the pathogenicity of the amoebae from the 

 results of injection into animals of these mixed cul- 

 tures containing both amoeba? and pathogenic bacteria. 



Cultures from Water. The method recommended 

 by Musgrave and Clegg for securing cultures of 

 amoebae from water is the following: 



From 100 to 500 c.c. of the water to be examined 

 is collected in a sterile flask and y 2 to 1 c.c. of 1 per 

 cent, alkaline bouillon is added to each 100 c.c. of the 

 sample. The flask is stoppered with cotton, and 

 placed in the dark for from 48 to 72 hours, and at 

 the end of this time a loopful of the water from the 

 surface is examined for amoebge. A loopful is then 

 spread over the surface of the medium used, prefer- 

 ably that described above, which has been poured into 

 a Petri dish. The plate should be examined at the end 

 of 24 hours, and in many instances amoebae will be 

 found at that time, but sometimes several days elapse 

 before the cultures develop. It is not necessary to 

 use a symbiotic bacterium, as the amoebae will find 

 suitable bacteria in the water. 



Cultures from Feces. For the cultivation of 

 amoebae from feces the following method is recom- 

 mended by Musgrave and Clegg: 



The surface of the special culture medium, con- 

 tained in Petri dishes, is smeared with a culture of 



