260 BACTERIA, YEASTS, AND MOLDS 



applied dry if the material to be disinfected contains mois- 

 ture, but it acts only in the presence of moisture and should 

 usually be dissolved in water. A solution of one part to 

 twenty-five of water (one pound to six gallons) is proper for 

 use, and is extremely efficient in disinfecting walls, floors, 

 furniture, etc. Its efficacy is due to the chlorine gas liber- 

 ated from it. 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 method of procedure is to shut up in a room the 

 articles to be disinfected, tightly closing all cracks around 

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

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

 that can be tightly closed, and this of course materially 

 limits its 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 

 is a very effective germicide, one part of formalin to ten 

 thousand parts of water being sufficient to destroy the vital- 

 ity of bacteria. Formalin has no more injurious action 

 upon clothing than common water would have. Hence 

 it may be used very freely in disinfecting any material 



