DISINFECTION 29 



sense. Any chemical agent which destroys or masks bad odours, 

 or which arrests putrefactive decomposition, is spoken of as a 

 disinfectant. And in the absence of any infectious disease it is 

 common to speak of disinfecting a foul cesspool, or a bad-smell- 

 ing stable, or a privy vault. 



" This popular use of the term had led to much misapprehen. 

 sion, and the agents which have been found to destroy bad 

 odours deodorisers, or to arrest putrefactive decomposition 

 antiseptics, have been confidently recommended and extensively 

 used for the destruction of disease germs in the excreta of patients 

 with cholera, typhoid fever, etc. 



" The injurious consequences which are likely to result from 

 such misapprehension and misuse of the word disinfectant will be 

 appreciated when it is known that recent researches have demon- 

 strated that many of the agents which have been found useful as 

 deodorisers, or as antiseptics, are entirely without value for the 

 destruction of disease germs. 



" This is true, for example, as regards the sulphate of iron, or 

 copperas, a salt which has been extensively used with the idea 

 that it is a valuable disinfectant. As a matter of fact, sulphate of 

 iron in saturated solution does not destroy the vitality of disease 

 germs, or the infecting power of material containing them. This 

 salt is, nevertheless, a very valuable antiseptic, and its low price 

 makes it one of the most available agents for the arrest of putre- 

 factive decomposition. 



" Antiseptic agents also exercise a restraining influence upon 

 the development of disease germs, and their use during epidemics 

 is to be recommended when masses of organic material in the 

 vicinity of human habitations cannot be completely destroyed, or 

 removed, or disinfected. 



" While an antiseptic agent is not necessarily a disinfectant, all 

 disinfectants are antiseptics; for putrefactive decomposition is 

 due to the development of * germs ' of the same class as that 

 to which disease germs belong, and the agents which destroy the 

 latter also destroy the bacteria of putrefaction, when brought in 

 contact with them in sufficient quantity, or restrain their develop- 

 ment when present in smaller amounts. 



