Disinfection of Sick-chambers, Etc. 187 



the permanganate, yet under conditions unfavorable to the 

 formation of oxides of manganese, such as usually coat the 

 grains of permanganate and prevent further reaction when 

 the formaldehyd solution is slowly added to the perman- 

 ganate without the precaution. 



The employment of calcium carbide for the same purpose 

 is suggested by Evans.* The best results were obtained 

 when the calcium carbide was in lumps about the size of a 

 pea; when the formaldehyd solution was diluted with an 

 equal volume of water, and when the diluted formaldehyde 

 was added to the carbide in the proportion of 5 c.c. of the 

 former to 3 grams of the latter. In the permanganate 

 method the quantity of formalin (or 37-40 per cent, for- 

 maldehyd in water) should equal 200 c.c. to 1000 cubic feet 

 of space, but in the carbide method 500 c.c. must be used to 

 achieve the same result. Evans, therefore, prefers the 

 permanganate method. 



To disinfect with formaldehyd or any gaseous disinfectant, 

 the room must be carefully closed, the cracks of the windows 

 and doors being sealed by pasting strips of paper over them. 

 If an apparatus is used, it is set in action, the discharged 

 vapor entering the room through the keyhole or some other 

 convenient aperture, the gas being allowed to act undis- 

 turbed for some hours, after which the windows and doors 

 are all thrown open to fresh air and sunlight. 



If sheets are hung up, or the permanganate method 

 employed, the windows and doors, other than that by means 

 of which the operator is to escape, are closed and sealed. 

 A dish-pan or wash-tub is placed in the center of the room, 

 and in it the can containing the permanganate and sand. 

 The formaldehyd solution is poured on, the operator making 

 his escape, closing and sealing the door behind him. Any 

 closets in the room must be left open so that they and their 

 contents may be disinfected with the room. 



So far as is known at present, superficial disinfection by 

 formaldehyd leaves little to be desired. Care must, how- 

 ever, be exercised to see that the required volume of gas 

 is generated to disinfect the apartment. A sufficient con- 

 centration of the gas is absolutely necessary, and the method 

 selected should be one capable of discharging the gas in a 

 short time, so that it immediately pervades the atmosphere. 



* "Reports and Papers of the American Public Health Association," 

 vol. xxxn, part n, p. 108, 1906. 



