COMMUNAL ACTIVITY OF BACTERIA 



257 



to do so. Obviously, from the conditions of the experiment we are 

 not deahng here with the usual chances that in a large inoculum 

 there are more vigorous cells than in a small one. The probabilities 

 just mentioned argue strongly against such a conclusion. 



Churchman and Kahn performed a number of experiments to 



Gentian 

 Violet 

 agar 



a 



Gentian 

 violet 

 agar 



Fig. 23. — Showing results of implantation of Bacillus subtilis on gentian-violet agar 

 without (left) and with (right) a thin layer of killed washed bacteria ih) below the 

 implants. C is redrawn from published halftone of the mass a below it. (From Church- 

 man.) 



