CHAPTER VII. 



DISINFECTANTS, ANTISEPTICS, AND 

 DEODORANTS. 



A DISINFECTANT is an agent which destroys the causes of 

 disease and their products, such as fire, steam (saturated), 

 boiling water, hot air, and chemicals in a proper strength 

 (5 per cent carbolic acid, 5 per cent permanganate of 

 potash, o-i per cent of perchloride of mercury, formalin, 

 cyllin, lysol, etc., and Cl, Br, and I and ozone). 



An antiseptic is an agent which arrests or impedes the 

 growth of micro-organisms without destroying their 

 vitality. Most of the disinfectants act thus in the weaker 

 strengths, as do also borax and boracic acid, sulphites and 

 sulphurous acid, salicylates and salicylic acid, essential 

 oils, quinine and other alkaloids, and common salt. 



A deodorant is an agent which masks or destroys the 

 effluvia produced by certain micro-organisms. Deodorants 

 include nitrous acid fumes, chlorine fumes (from chloride 

 of lime), sulphurous acid fumes, fumes of wood, tar, and 

 burnt paper, and some of the disinfectants in virtue of 

 their oxidizing power or their strong odour, such as 

 permanganate of potash and carbolic acid. 



Direct sunlight and fresh air are powerful factors in, and 

 aids to, disinfection, antisepsis, and deodorization. 



Bleaching Powder is prepared by passing Cl gas over 

 slaked lime, when a compound is formed having the 

 formula Ca (OC1) Cl, which liberates Cl gas on treatment 

 with acids. Theoretically it should contain 56 per cent of 

 available Cl ; a good bleaching powder commercially is 

 one which gives 35 per cent of available Cl. 



Ca(OCl)Cl + 2 HC1 = CaCl 2 + H 2 O + Cl 2 . 



Process. Pinot's Method. 



Solutions required : (i) Standard arsenious solution. 

 Dissolve 4-95 grm. of pure arsenious oxide in about 



