MECHANISM OF DEATH 



353 



been limited therefore, to the simplest way of measur- 

 ing concentrations. It seems that different ?2-values 

 can be obtained for the same disinfectant with different 

 bacteria. A comprehensive study of the concentration 

 exponents would seem quite desirable. The table 

 seems to indicate that aside from the value 0.5, the 

 n-values are very nearly integers. 



Whatever may be the theoretical explanation of 

 these n-values, their existence is beyond doubt. The 

 great differences for various disinfectants and bacteria 

 make comparisons almost impossible. Chick (1908) 

 and Phelps (1911) have both called attention to the 

 fact that the customary method of stating the dis- 

 infectant power by the ^^ phenol coefficient" or ''carbolic 

 acid coefficient" cannot possibly give results which 

 allow a general application. 



Table 110. — Concentration Exponents for the Potency of 

 Various Disinfectants 



HgCl2 (anthrax spores) n = 0.25 Alfred Miiller (1920) p. 362 



Oxygen (dry bacteria) 0.5 Paul (1910) p. 305 



HCl (Micrococci) 0.5 Paul, Birstein and Reuss 



(1910b) p. 348 



H2O2 0.5 Reichel, 1908 



HgCU (Micrococci) 0.5 Gegenbauer (1921) p. 360 



AgNOs 0.86 Chick (1908) 



Acetic acid 1.0 Paul, Birstein and Reuss 



(1910b) p. 348 



Formaldehyde 1.0 Gegenbauer (1922) p. 362 



HCl (anthrax spores) 1.5 Gegenbauer and Reichel (1913) 



Butyric acid 2 . 04 Paul, Birstein and Reuss 



(1910b) p. 348 



HgCla (BacL typhosum) 3.8 Chick (1908) 



HgCl2 (anthrax spores) 4.9 Chick (1908) 



Phenol (Bad. typhosum) 4.0 Reichel (1909) p. 357 



Phenol (Micrococci) 4.0 Reichel (1909) p. 357 



Phenol {Bad. paratyphosum) . . . 5.5 Chick (1908) 



Phenol (anthrax spores) 5 5 Chick (1908) 



Phenol {Bad. typhosum) 6.0 Lee and Gilbert (1918) 



