80 BACTERIOLOGY. 



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 death of 

 the spores, for if by proper means the combination of 

 mercury with their protoplasm was broken up, many 

 of the spores resumed their vitality, with all their pre- 

 vious 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 experi- 

 ments have given a new impulse to the study of disin- 

 fectants, and in the light shed by them many of our 

 previously formed ideas concerning the action of disin- 

 fecting agents have been modified. 



The process of disinfection 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 chem- 

 ical reaction occurring within more or less fixed limits ; 

 that is to say, with a given amount of the disinfect- 

 ant employed so much work, expressed in terms of disin- 

 fection — 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 inten- 

 sity and rapidity of the reaction become greater under 

 the influence of heat, so in the process of disinfection 

 the combination between the disinfectant and the organ- 

 isms to be destroyed is much more energetic at a tem- 

 perature of 37° to 39° C. than it is at 12° to 15° C. 



