CHEMICAL STERILIZATION AND DISINFECTION. 65 



they are applied. Often the materials containing the 

 bacteria to be destroyed are of such a character that 

 they combine with the disinfecting agent to form insol- 

 uble precipitates ; these so interfere with the penetration 

 of the disinfectant that many bacteria may escape its 

 destructive action entirely and no disinfection be accom- 

 plished, though an agent might have been employed 

 that would, under other circumstances, have given 

 entirely satisfactory results. 



In the destruction of bacteria by means of chemical 

 substances there occurs, most probably, a definite chemi- 

 cal reaction ; that is to say, the characteristics of both 

 the bacteria and the agent employed in their destruction 

 are lost in the production of an inert third body, the 

 result of their combination. It is impossible to say with 

 absolute certainty, as yet, that this is the case, but the 

 evidence that is rapidly accruing from the more recent 

 studies upon disinfectants and their mode of action points 

 strongly to the accuracy of this belief. This reaction, in 

 which the typical structures of both bodies concerned is 

 lost, takes place between the agent employed for disin- 

 fection and the protoplasm of the bacteria. For ex- 

 ample, in the reaction that is seen to take place between 

 the salts of mercury and albuminous bodies there results 

 a third compound, which has neither the characteristics 

 of mercury nor of albumin, but partakes of the pecu- 

 liarities of both ; it is a combination of albumin and 

 mercury known by the indefinite term "albuminate of 

 mercury." Some such reaction as this occurs when the 

 soluble salts of mercury are brought in contact with 

 bacteria. This view has recently been strengthened by 

 the experiments of Geppert, in which the reaction was 

 caused to take place between the spores of the anthrax 



