DISINFECTANTS AND DISINFECTION 329 



patients very quickly and completely, when used in 4 to 5 per cent. 

 solutions. 



As a gaseous disinfectant it is active in a moist, warm atmosphere. It 

 does, however, not kill insects and other higher organisms and in this 

 regard it is inferior to sulphur dioxide, but has the advantages of not 

 decolorizing fabric and being a better deodorant. There are several 

 proprietary disinfectants composed of soap and formalin, as lysoform. 



e. Sulphur. Sulphur in itself is odorless, tasteless and wholly inert as 

 a germicide, but when undergoing oxidation into sulphur dioxide (com- 

 bustion), in the presence of moisture, it is a very active disinfectant and 

 is at the same time fatal to insects and in fact to all forms of animal life, 

 including rats, mice, etc. But it cannot be used to disinfect fine fabrics, 

 paintings, books, etc., because of the destructive effects upon pigments. 



Under ordinary conditions the gaseous substances, as formaldehyde 

 (formalin) and sulphur dioxide, are surface disinfectants only and are used 

 where surface disinfection is all that is required, as in the sterilization of 

 clothing, wood work, walls, ceilings, pictures, furniture, etc. 



/. Bichloride of Mercury. This is the most potent and most exten- 

 sively used of all antiseptics. A i-iooo aqueous solution (used hot 

 whenever and wherever possible) makes a most satisfactory germicidal 

 wash for floors, walls, wood work of all kinds, in fact anything requiring 

 disinfection, excepting metals which would be corroded (excepting of 

 course platinum, gold, silver) and substances rich in albuminous matter 

 as pus, sputum, and other sick room discharges, which are coagulated by 

 this germicide, checking further action. 



The i-iooo solution is sufficiently powerful to kill all non-sporogenous 

 bacteria at the ordinary room temperature in one-half hour. For spores a 

 stronger solution (1-500) and longer exposure are desirable (one hour). 



The chief disadvantages to the use of corrosive sublimate are its 

 highly toxic nature, its corroding effect upon metals and its coagulating 

 effects upon albumen which hinders penetration. It should also be borne 

 in mind that soap interferes with the action of corrosive sublimate. 



A i-iooo solution is made as follows: 



Bichloride of mercury, 



Citric acid or salt, 61^ grs. 



Water, i gal. 



The sodium chloride or citric acid is added to retard the decomposition 

 of the bichloride. Tablets are now on the market made from mercury 

 cyanide. They are held to be more decidedly antiseptic than either the 

 iodide or the bichlorid of mercury, and are so prepared that one tablet 

 added to a pint of water will make a strength of i-iooo. 



