66 BACTERIOLOGY. 



bacillus and a solution of mercuric chloride, the result 

 being the apparent destruction of the vitality of the 

 spores by the formation of this third compound. In 

 these experiments it was shown that though this com- 

 bination had taken place, still it did not of necessity 

 imply the complete death of the protoplasm of the 

 spores, for if by proper means the combination of mer- 

 cury with their protoplasm was broken up, many of 

 the spores returned from their condition of apparent 

 death to that of life, with all their previous disease- 

 producing and cultural peculiarities. Geppert employed 

 a solution of ammonium sulphide for the purpose of de- 

 stroying the combination of spore-protoplasm and mer- 

 cury ; the mercury was precipitated from the proto- 

 plasm as an insoluble sulphide, and the protoplasm of 

 the spores returned to its original condition. These and 

 other somewhat similar experiments have given an 

 entirely new impulse to the study of disinfectants, and 

 in the light shed by them many of our previously 

 formed ideas concerning the action of disinfecting 

 agents must be modified. The process is not a catalytic 

 one i. e., occurring simply as a result of the presence 

 of the disinfecting body which is not of itself destroyed 

 in its process of destruction but is, as said, a definite 

 chemical reaction which takes place within certain more 

 or less fixed limits ; that is to say, with a given amount 

 of the disinfectant employed, just so much work, ex- 

 pressed in terms of disinfection destruction of bacteria 

 can be accomplished. 



Another point in favor of this view is the increased 

 energy of the reaction with elevation of temperature. 

 Just as in many other chemical phenomena, the intensity 

 of the reaction becomes greater under the influence of 



