CHEMICAL STERILIZATION, ETC. 67 



tion of mercuric chloride, the result being the apparent 

 destruction of the vitality of the spores by the forma- 

 tion of this third compound. In these experiments it 

 was shown that though this combination had taken 

 place, still it did not of necessity imply the complete 

 death of the spores, for if by proper means the com- 

 bination of mercury with their protoplasm was broken 

 up, many of the spores returned from their condition 

 of apparent death to that of life, with all their previ- 

 ous disease-producing and cultural peculiarities. Gep- 

 pert employed a solution of ammonium sulphide for 

 the purpose of destroying the combination of spore- 

 protoplasm and mercury; the mercury was precipi- 

 tated from the protoplasm as an insoluble sulphide, 

 and the protoplasm of the spores returned to its original 

 condition. These and other somewhat similar ex- 

 periments 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 itself decomposed during its process of destruction 

 — but is, as said, a definite chemical reaction occurring 

 within more or less fixed limits — that is to say, with a 

 given amount of the disinfectant employed just so 

 much work, expressed in terms of disinfection — des- 

 truction 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 inten- 

 sity of the reaction becomes greater under the influence 

 of heat, so in the process of disinfection the combination 



