160 BACTERIOLOGY. 



atmosphere for the same time, 4 per cent, was effective, 

 and when the time was extended to three hours, 1 per 

 cent, destroyed their vitality. The anthrax bacillus, 

 in the absence of spores, was killed by exposure in a 

 moist atmosphere containing 1 part to 2500 for twenty- 

 four hours. 



In watery solutions 0.2 per cent, kills spores within 

 five minutes and the vegetative forms almost imme- 

 diately. 



Chloride of Lime. The efficacy of chloride of lime 

 depends on the chlorine it contains in the form of 

 hypochlorites. A solution in water of 0.5 to 1 per 

 cent, of chloride of lime will kill most bacteria in one 

 to five minutes. A 5 per cent, solution usually de- 

 stroys spores within one hour. 



Bromine and iodine are of about the same value as 

 chlorine for gaseous disinfectants, in the moist condition; 

 but, like chlorine, they are not applicable for general 

 use in house disinfection, owing to their poisonous and 

 destructive properties; they have a use in sewers and 

 similar places. 



Trichloride of iodine in 0.5 per cent, solution de- 

 stroys the vegetative forms of bacteria in five minutes. 



ORGANIC DISINFECTANTS. 



Alcohol in 10 per cent, solution inhibits the growth 

 of bacteria; absolute alcohol kills bacteria in the vege- 

 tative form in from several to twenty-four hours. 



Formaldehyde. Formaldehyde, or formic-aldehyde, 

 was isolated by von Hoffmann in 1867, who obtained 

 it by passing the vapors of methyl-alcohol mixed with 

 air over finely divided platinum heated to redness. 



