CALCIUM HYDROXIDE-HYDROGEN PEROXIDE. 57 



are less irritating than the nitrate, but the clinical reports 

 are so contradictory that it is impossible to determine their 

 antiseptic value with any degree of positiveness. Hardly any 

 two men favor the same compound. 



Calcium hydroxide, or slaked lime, in 3 per cent, solution, 

 kills the typhoid bacillus in six hours ; 6 per cent., in two 

 hours. By adding 2 per cent, of milk of lime containing 20 

 per cent, of calcium hydroxide to typhoid stools the bacillus is 

 killed in one hour. It is not effective against the tubercle 

 bacillus nor against anthrax spores. It is used very widely as 

 a disinfectant of typhoid dejecta, and is far superior to either 

 bichloride or carbolic acid for this purpose. An excess of lime 

 should be used in order to insure perfect results. The chlori- 

 nated lime from which the milk of lime is made should con- 

 tain not less than 25 per cent, of chlorine. It should always 

 be freshly prepared, as it decomposes rapidly. 



Boric acid is practically worthless as a disinfectant. A satu- 

 rated solution fails to kill pus cocci in two hours. It is a 

 very weak antiseptic. A 5 per cent, solution failed to destroy 

 anthrax spores in five days (Koch). It is used very widely 

 as a dusting-powder on wounds. 



Alcohol (absolute) kills the tubercle bacillus after five min- 

 utes' exposure. Alcohol in 40 per cent, solution kills the pus 

 cocci in two hours. 



Pyoktanin : Many of the anilin dyes are germicides, espe- 

 cially blue pyoktanin or methyl-violet. The pus cocci and 

 anthrax bacilli are killed in thirty seconds by a 1 : 1000 solu- 

 tion ; the typhoid bacillus in thirty minutes. Malachite- 

 green possesses even greater germicidal value than pyoktanin. 

 The objection to these dyes is that they stain and discolor 

 the tissues. 



Chlorine : All the haloid elements are active germicidal 

 agents. Chlorine combines readily with hydrogen and liber- 

 ates nascent oxygen. It is most active in the presence of 

 moisture. A moist atmosphere, containing the gas in the 

 proportion of 1 : 2500, kills the anthrax bacillus in twenty- 

 four hours. In the proportion of 1 : 200 it kills the tubercle 

 bacillus in an hour. 



Hydrogen peroxide : The solutions on the market are ex- 



