PHYSICAL AND CHEMICAL AGENTS 35 



Lime which is to be used for disinfecting purposes 

 should be freshly slaked, as " air-slaked " lime has 

 no antiseptic value. It is said that a 20 per cent 

 solution of freshly slaked lime mixed with half its 

 bulk of typhoid excreta, will bring about complete 

 disinfection within an hour. 



Chlorinated Lime (Chlorid of lime) has also long 

 been used as a disinfectant, and is especially valuable 

 for the disinfection of sewage and water. For cellars 

 and privies it is used as a dry powder, but for dis- 

 infecting the excreta from communicable diseases a 

 solution (6 ounces to a gallon of water) is used ; the 

 same solution is also excellent for disinfecting floors 

 and other woodwork. An easy method of disin- 

 fecting drinking water is to add 1 gram (15 grains) 

 of chlorinated lime to 1 liter of water, and after 

 thorough mixing use this solution in the proportion of 1 

 part to 200,000 parts of water, mix well, allow to stand 

 20 minutes and the water may be regarded as safe. 



Sulphur is another disinfectant which has long been 

 in use . Sulphur dioxide is produced by burning the sul- 

 phur, the process being known as sulphur fumigation. 



The value of sulphur fumigation depends upon the 

 presence of moisture, 1 dry fumigation being practically 



1 One fifth pound of water to each pound of sulphur should 

 be allowed to each 250 cubic feet of air space. 



