ii2 METHODS OF STERILISATION. 



80. Organic Antiseptics. 



The antiseptic most appreciated next to sublimate in surgery, 

 viz., carbolic acid (Phenol, C 6 H 5 OH), which is used as a 4 per 

 cent, solution for washing wounds, is never employed for industrial 

 purposes. Nevertheless, it merits brief mention here because the 

 discoverer of its antiseptic action, viz., J. LEMAIRE (I. and II.), 

 established the interesting fact that this constituent of coal-tar, 

 whilst capable of restricting the development of organised ferments, 

 leaves the efficiency of the enzymes unimpaired, a differential be- 

 haviour which afforded support to Pasteur in his campaign against 

 the Liebig theory of fermentation. The toxic action of phenol 

 on the individual species of the bacteria varies, a circumstance 

 which is utilised in the bacteriological analysis of water. In order 

 to determine if the water under examination for impurities con- 

 tains Bacterium coli commune, a small quantity is, in accordance 

 with Pere's suggestion, placed in bouillon containing one part of 

 carbolic acid per mil. This will retard the development of most 

 of the water bacteria, but not that of B. coli commune, which will 

 therefore increase in the culture and can then be more readily 

 detected by supplementary means (plate cultures). Crude carbolic 

 acid is soluble with difficulty in pure water, but readily so in 

 sulphuric acid, combining therewith to form sulpho-acids, an 

 aqueous solution of which, under the name of aseptol, is employed 

 in surgery. According to the researches of R. Koch, the strength 

 of aqueous carbolic acid solution requisite to prevent the germina- 

 tion of the spores of B. antliracis is i part in 850. In a 5 per 

 cent, solution the death of these spores is caused only after more 

 than forty days. 



The three succeeding higher homologues of phenol, viz., the 

 cresols, C 6 H 4 .OH.CH 3 , are also used in surgery. The so-called 

 kreolin or creolin is a mixture of soap with a tar-oil, containing 

 a small quantity of phenols (cresol, &c.) and a large amount of 

 hydrocarbons. As the last are insoluble in water, a milky emulsion 

 is produced by pouring creolin into that liquid. Lysol and sapo- 

 carbol are mixtures of soap and tar-oils containing more phenols 

 and a smaller proportion of hydrocarbons than the substance last 

 described ; both these mixtures will dissolve in water without 

 producing turbidity. The solubility of the cresols in water is 

 slight: about i part per 100 aq., but can be increased con- 

 siderably (as ascertained by Hueppe) by the presence of other 

 substances. Thus, when sodium cresotate is used, solveol is 

 obtained. An alkaline aqueous solution of sodium-cresol will 

 absorb a very large quantity of cresol, thereby forming solutol. 

 By adding to a 50-60 per cent, crude carbolic acid about 20 

 per cent, of its weight of mineral oil, a mixture known as saprol 

 is obtained, which is lighter than water and floats when applied 

 to fsecal matter. The suitability of this preparation for the con- 



