342 



PHYSIOLOGY OF BACTERIA 



(c) CHEMICAL CONSIDERATIONS REGARDING THE ACTION OF 

 DISINFECTANTS 



The study of disinfection on a biochemical basis 

 dates back to the investigation of Kronig and Paul 

 (1897) which might well be called a classic paper on 

 disinfection. This paper shows that the disinfectant 

 power of salts or acids depends upon their ionization. 

 This was proved by exposing spores of B. anthracis to 

 various mercury salts and counting the number of 

 colonies developing after the action of the salts had been 

 interrupted by washing with a 3 % solution of ammonium 

 sulfide. In the following table, the salts are arranged in 

 order of decreasing ionization. The survivors increase 

 with decreasing ionization. 



Table 105. — Action op Mercury Salts upon Spores of B. anthracis 



The same importance of ionization was also shown by 

 the decrease of efficiency of these solutions whenever 

 their mercury ion concentration was reduced by addition 

 of other salts with the same anion. 



In a similar way, the disinfection by salts of silver, 

 gold, copper has been tested, and efforts were made to 

 determine the disinfectant value of the metal salt anions. 



Further investigations concerned the acids and alkalies. 

 The next table shows that neither molar nor normal 



