434 DISINFECTION 



In 1884 was issued from the English Local Government Board 

 one of the first adequate statements respecting the principles of 

 disinfection, as applied to the facts known respecting bacteria.* 

 In that report Dr Franklin Parsons arrived at the following 

 important conclusions: (a) that all infected articles which could 

 be treated by boiling water could not be so well disinfected in 

 any other way as by simply boiling for a few minutes; (6) that 

 for articles which could not be so treated, high pressure steam, with 

 complete penetration, was most satisfactory ; and (c) where articles 

 would be injured by either boiling or steam, dry heat at 240 F., if 

 sufficiently prolonged, would be effectual. He found that with the 

 exception of anthrax spores all the infected materials he experimented 

 upon were destroyed after an hour's exposure to dry heat at 220 F., 

 or five minutes exposure to steam at 212 F. Anthrax spores 

 required four hours' dry heat at 220 F. Dry heat penetrates very 

 slowly into bulky and badly conducting articles, such as bedding. 

 Parsons also pointed out that at or above 250 F. "scorching" 

 occurred, and above 212 F. many kinds of stains were fixed in 

 fabrics, so that they could not be removed by washing. He advocated 

 that the standard of true disinfection should be the destruction of 

 the most stable infective matter known. 



Previously to this period, experiments had shown the efficacy of 

 washing articles in boiling water, and Koch had shown the value of 

 corrosive sublimate. He had also shown the inefficacy of dry heat, 

 and of a number of chemical substances which it had been supposed 

 were disinfectants. 



In 1887 the Committee on Disinfectants of the American Public 

 Health Association reported a number of findings, as the result of 

 experiment, which crystallised known facts. For infectious material 

 containing spores or sporulating bacilli they recommended burning, 

 steam under pressure 105 C. for ten minutes, boiling in water for 

 thirty minutes, chloride of lime 4 per cent., and mercuric chloride 

 1-500. If such material did not contain spores, or sporulating 

 bacilli, a 2 per cent, solution of chloride of lime sufficed, also mercuric 

 chloride 1-2000, carbolic acid 5 per cent., chlorinated soda 10 per 

 cent., and sulphur if 3 to 4 Ibs. per 1000 cubic feet, and exposure 

 not less than twelve hours. For excreta the Committee advised 

 chloride of lime 4 per cent., for soiled underclothing, bed linen, etc., 

 burning, boiling, or immersion for four hours in mercuric chloride 

 (1-2000), or carbolic acid (2 per cent.). For washing furniture 

 or hands the same solution of carbolic acid; for disinfecting the 

 bodies of the dead carbolic acid (5 per cent.), chloride of lime (4 per 

 cent.), or mercuric chloride (1-500); and for washing surfaces in 



* Report of Medical Officer of Local Government Board, 1884. 



