No. 4.] STABLE DISINFECTION. 377 



Chlorine gas is a powerful disinfectant and deodorizer. It 

 is rather more active than sulphur fumes, and also much 

 more irritating and corrosive. Like sulphur dioxide, chlor- 

 ine destroys bacteria more readily in an atmosphere contain- 

 ing 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 

 m 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 

 sufficient 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 ; ordin- 

 ary 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 

 sufficient. The longer it acts, however, the more thorough 

 the disinfection. 



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

 chlorine are to be used with great caution, to prevent acci- 

 dents. 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 diseased animals, including clothing, cleaning uten- 

 sils, pails, and even the hands of the person attending the 

 sick, should be carefully treated. Too great care cannot be 

 exercised in this connection. The success of getting rid of 

 contagious matter from a building depends wholly upon the 

 thoroughness of disinfection, provided the source of conta- 

 gion has been removed. 



