206 MANUAL OF BACTERIOLOGY. 



SO rapidly that only fresh solutions of known strength should 

 be used. 



Potassium Permanganate. — ^Koch asserts that a 3 per cent, 

 solution will destroy anthrax spores in twenty-four hours, but 

 that a I per cent, solution cannot be depended upon to kill 

 pathogenic organisms. Its disinfectant value in practice is 

 very low on account of its ready decomposition by inert ma- 

 terial. In the dilute solutions usually used for medicinal in- 

 jections and irrigations no disinfectant action occurs. 



Iodoform. — This substance possesses little if any disinfectant 

 power. It is mildly antiseptic in moist wounds, due to the 

 gradual liberation of small quantities of iodine. 



Boric Acid. — This material possesses practically no disin- 

 fectant power. It is a mild antiseptic when applied as an 

 undiluted powder to wounds. A saturated aqueous solution 

 is much used, and is weakly antiseptic. 



Essential Oils. — Many of these bodies possess germicidal 

 value, notably the oils of cinnamon and cloves. The oil of 

 mustard is also a valuable disinfectant, but so irritating that 

 the pure oil cannot be used. The use of powdered mustard 

 in the autopsy-room will remove the foul odor from the hands 

 more rapidly and completely than any other means. 



Coal Oil or Petroleum. — -While the disinfectant value of this 

 substance is sUght, its use in destroying the larvas of insects, 

 such as the mosquito, has given it an important position in 

 preventing the spread of malaria and yellow fever. A small 

 amount poured on a stagnant pool rapidly spreads over the 

 surface and effectually destroys such larvas. 



Ferrous Sulphate (Copperas). — ^This salt has been much, 

 used, but possesses only feeble disinfectant powers. A 3 per 

 cent, solution requires three days to kill the bacillus of typhoid 

 fever. On account of its afi&nity for ammonia and sulphides 

 it is an efficient deodorizer for temporary use, but cannot be 

 relied upon to kill the bacteria producing the noxious gases. 



