CHEMICAL STERILIZATION AND DISINFECTION. 95 



soda) solution for fifteen to twenty minutes, or placed 

 in the steam sterilizer for half an hour. 



Intestinal evacuations may best be disinfected with 

 boiling water or with milk of lime, a mixture composed 

 of lime in solution and in suspension ordinary fluid 

 " white-wash." This should be thoroughly mixed with 

 the evacuations until the mass contains a considerable 

 excess of the lime, and should remain in contact with 

 them for one or two hours. Excreta may also be easily 

 disinfected by thoroughly mixing them with two or 

 three times their volume of boiling water, after which 

 they are kept covered until cool. 



Sputum in which tubercle bacilli are present, as well 

 as the vessel containing it, must be boiled in 2 per cent, 

 soda solution for fifteen minutes, or steamed in the ster- 

 ilizer for at least half an hour. 



On the whole, in the laboratory we should rely more 

 upon the destructive properties of heat than upon those 

 of chemical agents. 



From what has been said, the absurdity of sprink- 

 ling here and there a little carbolic acid, or of placing 

 vessels of carbolic acid about apartments in which in- 

 fectious diseases are in progress, must be plain. Treat- 

 ment of water-closets and cesspools by allowing now 

 and then a few cubic centimetres of some so-called 

 disinfectant to trickle through the pipes is ridiculous. 

 A disinfectant must be applied to the bacteria, and must 

 be in contact with them for a long enough time to insure 

 the destruction of their life. 



In the light of the latest experiments upon disin- 

 fectants, the place formerly occupied by many agents 

 in the list of substances employed for the purpose will 

 most likely be changed as they are studied more closely. 



