CHEMICAL DISINFECTANTS 19 



various chemical substances are employed for the purpose 

 of sterilisation. Those possessing the greatest germicide 

 power of all are carbolic acid in strong solutions, corrosive 

 sublimate in 1 in 1,000 solutions, and quicklime; but next 

 to these chlorine, iodine, and bromine waters, 1 per cent, 

 solutions of osmic acid, 1 per cent, solutions of potassium 

 permanganate, oil of turpentine, iron percliloride , &c., have 

 a more or less energetic disinfectant action. Of the above 

 disinfectants, corrosive sublimate in 1 in 1,000 solution is 

 at present most in use. 



Heider states that the efficacy of a large number of 

 disinfectants is very markedly increased by moderately 

 raising the temperature. 



Chloroform is recommended by Kirchner as an excellent 

 disinfectant, having the advantage of great activity com- 

 bined with a low boiling-point, so that it can be driven off 

 with certainty from other fluids by heating after sterilisa- 

 tion is complete. It is particularly suitable for sterilising 

 blood serum, which cannot be exposed to a high tempera- 

 ture, and which, therefore, as Globig has shown, it is im- 

 possible to free by the method of discontinuous sterilisation 

 from the germs of such micro-organisms as do not grow 

 below 50 C., and are capable of withstanding a tempera- 

 ture of 70 C. To sterilise by this method the fluids under 

 treatment are shaken up with excess of chloroform, and 

 allowed to stand for some days, after which they are freed 

 from the chloroform before use by heating for an hour at 

 62 C., the boiling-point of chloroform being 61-2. 



In bacteriological work it is often necessary to com- 

 bine several modes of sterilisation in order to secure com- 

 plete destruction of germs, but the method chosen varies 

 continually according to the bodies to be so treated. For 

 the sterilisation of instruments, boiling for five minutes 

 in water is sufficient, according to Davidsohn ; and plates, 



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