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 Bad. anthracis, 

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



4-000 



3500 



o 



3000 



o 

 O, 



in 



** 



" 

 O 



2500 



9.000 



IOOO 



500 



o A 



10 



FIG. 121 Curve of disinfection. Spores of Bact. 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 



