Disinfection. 167 



hours in the space to be disinfected in order that the pro- 

 cess shall be effective. The gaseous disinfectants find 

 their greatest use in household disinfection, where the 

 rooms can be tightly closed by pasting strips of paper 

 over the door and window cracks. Formaldehyde, the 

 best gaseous disinfectant, finds but limited use in the 

 stable. Keliance must here be placed on the disinfect- 

 ants that can be applied in solution or suspension in 

 water. There are a considerable number of these but 

 three or four are by far the most important. 



Lime. Quick lime or stone lime is made by heating 

 lime stone to a very high temperature. The lime stone 

 is changed because of the loss of carbon dioxide, which 

 passes off as a gas during the burning of the lime stone. 

 The quick lime thus produced gradually changes on ex- 

 posure, to a powder known as air-slaked lime which has 

 the same composition as the original lime stone, and which 

 has no disinfecting action whatever. If the quick lime is: 

 treated with six parts of water to ten parts of lime, 

 water-slaked lime will be obtained, which, when prepared 

 in a cornet manner, is a dry white powder, resembling 

 air-slaked lime in appearance but not in composition. 

 This can be noted by placing a particle of each on the 

 tongue for a moment. The air-slaked lime tastes like so- 

 much chalk while the water-slaked soon causes the tongue 

 to burn. It is caustic lime and has disinfecting proper- 

 ties. It can be used as a dry powder, sprinkled on floors 

 and yards, or in a suspension, in water as whitewash. 

 The whitewash is best applied with a spray pump and for 

 this purpose must be made rather thin so as not to clog 

 the nozzle of the pump. Any of the hand spraying out- 

 fits are well adapted for the application of whitewash or 

 other disinfectants to the walls and ceilings of stables. 



