194 MANUAL OF BACTERIOLOGY. 



CHAPTER VIII. 



DISINFECTANTS AND ANTISEPTICS. 1 



A disinfectant or germicide is a substance capable of 

 killing bacteria. The latter term is of more recent develop- 

 ment than the former, and apparently needed on account 

 of the loose application of the term disinfectant. 



An antiseptic is a substance capable of preventing the 

 growth and reproduction of bacteria. It differs from a 

 disinfectant or germicide in that it simply prevents devel- 

 opment without actually killing. 



A deodorizer is a substance capable of so changing a 

 noxious odor that it is less unpleasant to the sense of smell. 

 At the present time the term is usually and properly re- 

 stricted to those substances which, without disinfectant ac- 

 tion, simply replace or destroy an odor. 



TESTING ANTISEPTICS AND DISINFECTANTS. 



The determination of the antiseptic value of a material 

 is a comparatively simple matter. A virulent culture of 

 the organism used as a test is inoculated into sterile bouil- 

 lon containing a known quantity of the antiseptic. The 

 process is repeated with varying strengths of the material 

 until the smallest quantity of it capable of preventing 

 growth is determined. This dilution may be considered 

 the antiseptic value of the material in question for the organ- 

 ism used, under the conditions of the test. 



1 By Thomas B. Carpenter, M.D., Assistant City Bacteriologist, 

 Buffalo, N. Y. 



