TABLE IV. 
B. fluorescens. B. typhosus growth. 
No: 29 Absent. 
No. 469 Absent. 
No. 502 Present. 
No. 3 Present. 
The active substance is not destroyed at the temperature of live 
steam under fifteen pounds pressure for fifteen minutes. 
CONCLUSIONS. 
The specific antagonism of 2B. fluorescens for B. typhosus is due to a 
substance secreted by the first named organism. 
This antagonism is not characteristic of all B. fluorescens cultures. 
There seems to be a correlation between the intensity of the color and this 
property. 
The action is bactericidal. 
B, fluorescens cultures with slight pigment production do not prevent 
the growth of B. typhosus. 
The metabolic substances must reach a certain concentration before 
they become effective. 
The toxic substances secreted by B. fluorescens have the following 
properties : 
1. They are thermo-stabile. 
2. They are diffusible through a collodion sae. 
Although the growth of B. fluorescens in milk would suggest a digestive 
process, the typhoid bacilli are not agglutinated when grown in a sterilized 
filtrate of the first named organism. 
