188 PRINCIPLES OF DISINFECTION 



Corrosive Sublimate, or Bichlorid of Mercury (HgCl 2 ). This is one 

 of the strongest antiseptics known, but its effectiveness is much de- 

 creased in the presence of albuminoids. This disadvantage can be 

 partially corrected by adding hydrochloric acid, tartaric acid, citric 

 acid, chloride of sodium, and other chemicals to the corrosive sublimate 

 solutions. Bichlorid solutions are also objectionable in that they 

 corrode metals, and are very poisonous. There is, however, hardly 

 any better disinfectant for stables and barns which have been infected 

 with anthrax bacilli and their spores. In this case the disinfectant 

 should be used in the strength of 1 to 500, and it is, of course, necessary 

 to proceed systematically so that all surfaces of walls and floors which 

 may have become contaminated are exposed to the action of the 

 solution. This may be accomplished by the use of mops or brooms 

 or an elevated tank connected with a rubber hose, or best by the 

 employment of a pressure pump. After thoroughly wetting every 

 surface the solution should be allowed to act for from one to two hours, 

 and then the place should be well cleaned with water. In the use 

 of bichlorid solutions it must be remembered that they are very power- 

 ful poisons to man and domestic animals, and that subsequent removal 

 by very thorough washing and flushing is necessary. Bichlorid can- 

 not be used to disinfect tubercular material, such as sputum, caseous 

 masses, etc., because the mercury salt forms a compound with albu- 

 minoids of very slight, if any, disinfectant value. 



Caustic Lime. Among other salts of the metals much used in 

 practical disinfection, caustic lime deserves to be mentioned. Its 

 effect depends upon its strongly alkaline reaction. On this account 

 old solutions in which the lime salt has combined with carbon dioxide 

 and formed carbonate of lime are of little or no value. The solution 

 must, therefore, be prepared immediately before use. The following 

 formula is recommended. Take a number of pounds of pure burnt lime 

 (CaO), add slowly and gradually for each ten pounds 1^ gallons of 

 water, and finally add 20 gallons of water and mix well. This mix- 

 ture will represent a 20 per cent, milk of lime which when fresh is 

 quite an effective disinfectant. 



Chlorinated Lime. This is also known as chloride of lime, or bleach- 

 ing powder, and is prepared by passing a stream of nascent chlorine 

 gas over moist unslaked lime (calcium hydrate). It is a soft white 

 friable substance, very slightly soluble in water, and of indefinite 

 chemical composition. Its disinfecting value depends chiefly upon 

 the amount of calcium hypochloride which it contains. Its bleaching 

 and destructive properties limit its employment as a germicide, but it is 

 used extensively in stables and barns for the disinfection of infected 

 fecal matter, urine, manure, bedding, floors, and woodwork, etc. 



Permanganate of Potash. In a 4 per cent, solution this is a very 

 powerful disinfectant and kills anthrax spores in about fifteen minutes. 



Carbolic Acid. Carbolic acid (C 6 H 5 OH) and other bodies belonging 

 to this group of chemicals are very important disinfectants. They 



