AMCEBJE PREFER CERTAIN BACTERIA 95 

 NAME OF BACTERIUM REMARKS 



Excystation 

 occurs, but the 



Amoeba parasite 



amoeba* rapidly 

 degenerate. 



From a general survey of these results we find 

 that the most suitable bacteria with which to 

 cultivate amoebae are those that naturally occur in 

 water. The pathogenic bacteria, and those which 

 produce toxic substances (e.g. neurine) and foul 

 gases, such as B. coli, B. brunneum, etc., are not 

 good, for, although cultures can be obtained with 

 them, the amoebae do not thrive and encyst before 

 much multiplication takes place. 



It should be mentioned that spirilla-like bodies 

 often appear in pure cultures with motile bacteria, 

 particularly B. f. liquefaciem. They are motion- 

 less and often show knobbed or frayed-out ends, 

 and are probably the cast-off flagellas of the bacilli 

 as described by Gauducheau. 



APPENDIX 



BACTERIOLOGICAL ANALYSES DURING THE 

 PREPARATION OF "PURE MIXED CULTURES" 

 OF AMCEBA. 



THESE were undertaken at a stage when cysts 

 had been obtained in apparently pure culture after 

 treatment of an impure culture with 2-per-cent. 

 formalin for a week. Bacillus fluorescens lique- 

 faciens had already been isolated, and the formalised 

 cysts were mixed with some of these, and the 



