DISINFECTANTS. ANTISEPTICS 181 



Corrosive sublimate 1 : 1000 kills anthrax spores after 24 hours 

 (von Behring). 



Influence of the Form of the Disinfectant. — The different 

 conditions of aggregation exert a definite influence upon the degree 

 of antiseptic action. SoHd, insoluble bodies possess no disinfec- 

 tant action because they cannot penetrate the mass to be dis- 

 infected. Disinfectants in solution in water are most effective. 

 Alcoholic solutions are also very effective when the solvent is 

 alcohol diluted with water. On the other hand, solutions in oil 

 are not effective, as was demonstrated by Koch in connection 

 with carbolized oil. Disinfectants in the gaseous form are very 

 unreliable, except formaldehyde. Koch was the first to demonstrate 

 the inefficiency of sulphurous acid, which was formerly so highly val- 

 ued as a disinfectant. The practical value of chlorine and bromine 

 in the gaseous form has been placed in great doubt by von Behring. 

 Even calcium chloride is disinfectant in slight degree in the gaseous 

 form only when the object to be disinfected is moist, when the bac- 

 teria are entirely superficial and when 13^ per cent, by volume of 

 free chlorine is developed in the area to be disinfected. Many other 

 superior antiseptics are not suitable for practical use because they 

 are not soluble in water. These include, first of all, the ethereal oils, 

 which in alcoholic solutions possess a very high disinfectant action. 

 The behavior of iodoform, which is in powder form, is pecuHar ; it be- 

 comes antiseptic only after it is decomposed and iodine is set free. 



Time of Disinfection. — In many cases it is very important 

 that the disinfection be undertaken within a certain time. This 

 applies especially to the disinfection of wounds. Fresh wounds 

 are much easier disinfected than old, suppurating wounds. The 

 prompt use of a suitable disinfectant (tannoform) on fresh wounds 

 will prevent suppuration. On the other hand, the disinfection of 

 old wounds is difficult and frequently impossible on account of 

 the bacteria having penetrated deeply into the tissues. In an- 

 thrax, tetanus and rabies, disinfection should be undertaken at the 

 earliest possible moment after the diagnosis is made, especially 

 in anthrax, in order to prevent the easily destroyed bacilli from 

 developing the highly resistant spores. 



