256 MANUAL OF BACTERIOLOGY. 



cent, of the dry gas is fatal to anthrax spores in three hours. 

 The anthrax bacillus is killed in twenty-four hours by ex- 

 posure to a moist atmosphere containing the gas in the pro- 

 portion of 1-2500. The bacillus of tuberculosis is killed by an 

 exposure of one hour to a moist atmosphere containing the gas 

 in the proportion of 1-200. Extremely minute quantities in 

 solution will prevent the development of putrefactive organ- 

 isms. The substance has been used for house and ship disin- 

 fection, but is now seldom employed on account of its extremely 

 irritating properties and the difficulty of handling. 



Bromine. Used in the gaseous and liquid form. The dry 

 vapor possesses but little disinfectant power; when moist it 

 is much more efficient. In saturated acqueous solution it will 

 kill the anthrax bacillus in twenty-four hours. 



Calcium Hypochlorite, usually known as Chloride oj Lime. 

 This is a most practical and valuable disinfectant, depending 

 for its efficiency on the available chlorine contained in it. Its 

 alkalinity favors penetration, and for many purposes it can- 

 not be excelled. A i per cent, solution will destroy anthrax 

 spores in one hour. A solution of the same strength will disin- 

 fect typhoid stools in ten minutes. 



Lime. The addition of o.i per cent, of unslaked lime to 

 fluid-cultures of the typhoid bacillus and cholera spirillum will 

 render them sterile in four or five hours. Typhoid dejecta are 

 sterilized in six hours by the addition of 3 per cent, of slaked 

 lime; the addition of 6 per cent, will accomplish the same result 

 in two hours. A convenient form for practical use is an aqueous 

 mixture containing 20 per cent, of lime so-called milk of 

 lime. Typhoid and cholera dejecta are sterilized in one hour 

 after the addition of 20 per cent, of this mixture. In practice 

 it is safer to use a considerable excess of lime. From the fore- 

 going facts it would seem probable that lime or whitewash as 

 ordinarily applied would possess disinfectant properties. Ex- 

 perimental work has demonstrated this to be a fact. The 



