i84 Sterilization and Disinfection 



had been placed upon the market. Care must be exercised in 

 handling the iluid, that the hands do not become wet with it, as it 

 hardens the skin and deadens sensation. The vapor is exceedingly 

 irritating to the mucous membrane of the eyes and nose. 



The solution can be employed to spray the walls and floors of 

 rooms, though Rosenau* finds that unless the spray discharged 

 from a large atomizer be very fine, its action is uncertain. 



The original method of disinfection, suggested by Robinson,t 

 consisted of the evolution of the gas by volatizing methyl alcohol, 

 and passing the vapor over heated asbestos. Shortly many efficient 

 forms of apparatus were placed upon the market, for the evolution 

 of the gas or for discharging it from the solution. 



It is not necessary to use a special apparatus in order to disinfect 

 with formaldehyd; one can, in an emergency, hang up a number 

 of sheets, saturated with the 40 per cent, solution, in the room to 

 be disinfected. The number of sheets must vary with the size of 

 the room, as each is able to evolve but a certain amount of the gas, 

 and the quantity necessary for disinfection varies with the size of 

 the room. 



One of the best methods of evolving the gas for purposes of dis- 

 infection is that devised by Evans and Russell f who combine the 

 40 per cent, solution of formaldehyd with permanganate of 

 potassium, when an almost explosive liberation of the gas takes place. 



Frankforterl found that a good method of escaping the un- 

 desirable features of the gaseous evolution was to mix the powder 

 of permanganate of potassium with an equal volume of sand, so 

 that the formaldehyd solution is brought more slowly into contact 

 with the permanganate, under conditions unfavorable to the forma- 

 tion of oxids of manganese, such as otherwise tend to coat the grains 

 of permanganate and prevent further reaction between the formal- 

 dehyd solution and the permanganate. 



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 formal- 

 dehyd solution was diluted with an equal volume of water, and when 

 the diluted formaldehyd was added to the carbide in the propor- 

 tion of 5 cc. of the former to 3 grams of the latter. . In the perman- 

 ganate method the quantity of formalin (or 37-40 per cent. 

 formaldehyd in water) should equal 300 cc. to 1000 cubic feet of 

 space, but in the carbide method 500 cc. must be used to achieve 

 the same result. Evans, therefore, prefers the permanganate 

 method. 



*" Disinfection and Disinfectants," P. Blakiston's Son & Co., Philadelphia, 

 1902. 



t "Ninth Report of the State Board of Health of Maine," 1896. 



t "Reports and Papers of the American Public Health Association," 1906, 

 vol. XXXII, part 11, p. 114. 



§ Ibid., p. 108. 



