39 



Chlorine gas is a powerful disinfectant and deodorizer. It is 

 rather more active th^n sulphur fumes, and also much more irri- 

 tating and corrosive. Like sulphur dioxide, chlorine destroys 

 bacteria more readily in an atmosphere containing large quantities 

 of moisture rather than in one free from it ; hence the advisability 

 of sprinkling the floors and walls before using. It requires about 

 one per cent of chlorine gas in the atmosphere in order to be sure 

 of disinfection. It is easily generated by adding hydrochloric or 

 sulphuric acid to chloride of lime or ordinary bleaching powder. 

 Five and one-half pounds of chloride of lime and an equal quantity 

 of sixty per cent sulphuric acid mixed together will produce suffi- 

 cient chlorine gas to disinfect one thousand cubic feet of space. 



Care must be taken in using the sulphuric acid, as it is very 

 caustic. It acts less violently when added to the lime if diluted 

 by the addition of an equal quantity of water. If diluted, five 

 and one-half pounds of acid must be used, the same as if no water 

 were added. The acid and lime should be mixed either in earthen, 

 glass or wooden vessels ; ordinary stone jars are suitable for this 

 purpose. Metals of all kinds are quickly destroyed by the acid. 



The chlorine gas does not require as long a time to destroy 

 germs as does sulphur dioxide ; five or six hours are usually suffi- 

 cient. The longer it acts, however, the more thorough the disin- 

 fection. 



It is always to be borne in mind that sulphuric acid and chlorine 

 are to be used with great caution, to prevent accidents. During 

 fumigation all animals should be removed from the building, and 

 should not be returned until it has been well aired. 



In the work of disinfection it is all-important that it be done 

 thoroughly. Everything which has come in contact with the dis- 

 eased animals, including clothing, cleaning utensils, pails, and 

 even the hands of the person attending the sick, should be care- 

 fully treated. Too great care cannot be exercised in this connec- 

 tion. The success of getting rid of contagious matter from a 

 building depends wholly upon the thoroughness of disinfection, 

 provided the source of contagion has been removed. 



