DISINFECTANT AGENTS. 53 



ing now and then a few cubic centimetres of some so- 

 called disinfectant to trickle through the pipes is a 

 failure. A disinfectant must be applied to the bacteria, 

 and must be in contact with them for a long enough time 

 to insure the destruction of their life. In the light of the 

 latest experiments upon disinfectants, the place formerly 

 occupied by many agents in the list of substances em- 

 ployed for the purpose will most likely be changed as 

 they are studied more closely. 



The agents, then, which will prove of most value in 

 the laboratory for the purpose of rendering infectious 

 materials harmless are : Heat, either by burning, by 

 steaming for from half an hour to an hour, or by boiling 

 in a 2 per cent, soda solution for fifteen minutes ; a solu- 

 tion of chlorinated lime (" chloride of lime "), in which 

 the percentage of chlorine is high ; and milk of lime. 

 The materials to be disinfected in either of the lime 

 solutions should remain in them for several hours. The 

 solutions should be freshly prepared when needed, as 

 they rapidly decompose upon standing. 



Antiseptic. An antiseptic is a body which, by its 

 presence, prevents the growth of bacteria without of 

 necessity killing them. A body may be an antiseptic 

 without possessing disinfecting properties to any very 

 high degree, but a disinfectant is always an antiseptic 

 as well. 



