VII. 

 ANTISEPTICS AND DISINFECTANTS. 



GENERAL ACCOUNT OF THE ACTION OF. 



THE term antiseptic is used by some authors to designate an 

 agent which destroys the vitality of the microorganisms which pro- 

 duce septic decomposition, and others of the same class. We prefer 

 to restrict the use of the term to those agents which restrain the de- 

 velopment of such microorganisms without destroying their vitality. 

 The complete destruction of vitality is effected by germicides or dis- 

 infectants. Material containing the germs of infectious diseases is 

 infectious material, and we disinfect it by the use of agents which 

 destroy the living disease germs or pathogenic bacteria which give 

 it its infecting power. Such an agent is a disinfectant. But we ex- 

 tend the use of this term to germicides in general that is, to those 

 agents which kill non-pathogenic bacteria as well as to those which 

 destroy disease germs. All disinfectants are also antiseptics, for 

 agents which destroy the 'vitality of the bacteria of putrefaction ar- 

 rest the putrefactive process ; and these agents, in less amount than 

 is required to completely destroy vitality, arrest growth and thus 

 act as antiseptics. But all antiseptics are not germicides. Thus a 

 concentrated solution of salt or of sugar will prevent the putrefac- 

 tive decomposition of organic material, animal or vegetable ; but these 

 agents do not destroy the vitality of the germs of putrefaction. In 

 a certain degree of concentration they are antiseptics and are largely 

 used for the preservation of meats and vegetables. In the same way 

 many mineral salts in solutions of various strengths act as antisep- 

 tics, and some of these in still stronger solutions are disinfectants. 

 Thus mercuric chloride, when introduced into a culture solution in 

 the proportion of 1 : 300,000, will restrain the development of anthrax 

 spores, but to insure the destruction of these spores a solution of 

 1 : 1,000 must be used. As a rule, the difference between restraining 

 action antiseptic and germicidal power disinfectant is not so 

 great as this. We give below some recent determinations by Boer 

 which illustrate this point, the test organism being the bacillus of 

 typhoid fever in a culture in bouillon twenty-four hours old : 



