THE METHODS OF DISINFECTION. 81 



filter of unglazed Sevre porcelain is the only one to be recom- 

 mended for this purpose. 



FIG. 43. 



Chamber for sterilizing and solidifying blood-serum. (Koch.) 



THE METHODS OF DISINFECTION. 



I. Disinfection or destruction of infectious bacteria may with 

 certainty be accomplished by heat, and indeed in the labora- 

 tory when the total destruction of the bacteria is desired 

 with the material containing them heat is the most effective 

 measure. 



In other cases, however, when the destruction of the bac- 

 teria themselves and the preservation of the contaminated sub- 

 stance are desired, recourse must be had to such measures as 

 will destroy the bacteria alone. 



Substances which are able to destroy bacteria or their 

 spores are known as germicides or disinfectants, and those 

 substances which retard bacterial growth are called antiseptics. 



II. In the use of chemicals for disinfecting, one should 

 always bear in mind that their mode of action is not a cata- 

 lytic one, but that they owe their virtue to the power of 



6 M. B. 



