INHIBITION OF GROWTH 



289 



heat or drying. The number of cells dying in a given time interval is 

 proportional to the number of cells surviving. In the last five years, 

 this has been tested and found true with practically all disinfectants. 

 Fig. 1 2 1 shows the curves plotted from data obtained with BacL anthracis, 

 the full-drawn line representing the number of live spores in .21 per 



3500 



3000 

 I 



2000 



1500 



IOOO 



500 



o . 



10 



FIG. i2i Curve of disinfection. Spores of Baa. anthracis in mercuric chloride 

 solution. (After Chick.) 



cent of mercuric bichloride, the dotted line the same in .11 per cent 

 solution. 



The (apparent) resistance of the few remaining cells is of great im- 

 portance in those applications of disinfection where a thorough kill- 

 ing of all bacteria is intended, e.g., in the treatment of drinking water. 

 Our ideas of the efficiency of a disinfectant would depend, therefore, 



19 



