CHEMICAL DISINFECTING AGENTS 261 



applied dry if the material which is to be disinfected con- 

 tains moisture, but it acts only in the presence of mois- 

 ture and should usually be dissolved in water. A solution 

 of one part to twenty-five of water (one pound to six 

 gallons) will be found to be very efficient in disinfecting 

 walls, floors, furniture, etc. Chloride of lime is also one 

 of the most efficient disinfectants for water. When added 

 in very minute quantities, only one part of chlorine to a 

 million of water, it kills the disease germs and is perfectly 

 harmless in the water. It is very widely used to-day for this 

 purpose and its use is extending rapidly. Common slacked 

 lime, which is occasionally used, is of little value as a 

 disinfectant. 



Sulphur. The fumes of burning sulphur have been 

 widely employed for disinfecting rooms, partly because of 

 its efficacy and partly because of ease of application. The 

 common tnethod of procedure is to shut up in a room the 

 articles to be disinfected, tightly closing all cracks around 

 doors, wihdows, keyholes, etc., and to burn a quantity of 

 sulphur ih the room. Sulphur can be used only in spaces 

 that can be tightly closed, and this of course materially 

 limits it^ application. It has the disadvantage of not 

 readily destroying bacteria spores, and therefore not being 

 absolutely effective. In spite of this fact it is found to 

 be of great practical value, and has been very widely and 

 successfully used by boards of health. 



Formalin. The desirability of some disinfectant in the 

 form of a gas that can be used for disinfecting rooms, etc., 

 has led to the use of a new disinfectant known as formalin. 

 This material, as purchased, looks like water, and consists 

 of a poisonous gas dissolved in water. The liquid itself 



