204 MANUAL OF BACTERIOLOGY. 



sulphur burning, and for this reason it is surer and more 

 convenient to use the so-called sulphur candles now on the 

 market. In operating with these, a sufficient number are 

 placed on bricks in a pan of water and the wicks lighted. 

 Liquefied sulphur dioxide may be used, and can now be ob- 

 tained in convenient tin receptacles containing a sufficient 

 quantity for the disinfection of an ordinary room. The can 

 is opened by cutting through a soft metal tube projecting from 

 the top. The fluid vaporizes at the room temperature, and it 

 is simply necessary to place the can in a convenient porcelain 

 dish and allow the fluid to evaporate. 



Sulphur dioxide is objectionable on account of its lack of 

 power when dry, and on account of its corrosive action on 

 metal and its bleaching effect on hangings and draperies in 

 the presence of moisture; it is, therefore, preferable to use 

 formaldehyde when possible. 



Chlorine. — ^A very active gaseous disinfectant, particularly 

 in the presence of moisture. An atmosphere containing i per 

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

 The anthrax bacillus is killed in twenty-four hours by 

 exposure to a moist atmosphere containing the gas in the 

 proportion 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 quan- 

 tities in solution will prevent the development of putrefactive 

 organisms. The substance has been used for house and ship 

 disinfection, but is now seldom employed on account of its 

 extremely irritating properties and the difficulty of handling. 



Bromine. — Used in the gaseous and Hquid form. The dry 

 vapor possesses but Httle disinfectant power; when moist it 

 is much more efficient. In saturated aqueous solution it will 

 kill the anthrax bacillus in twenty-four hours. 



Calcium Hypochlorite, usually known as Chloride of Lime. — 

 This is a most practical and valuable disinfectant, depending 



