214 VETERINARY HYGIENE 



Fluid and forms a white emulsion with water. Published analyses 

 state that it contains 60 per cent, hydrocarbons boiling at 190 to 

 350 C, and 10 to 22 per cent, phenols boiling at 200 to 350 C. 



JEYES FLUID is a preparation of tar oils and owes its bactericidal 

 properties to the comparatively non-toxic higher phenols. It is a 

 reliable disinfectant. 



Carbolic acid is caustic and coagulates albumen. It is 

 soluble in water up to 5 per cent., and is less soluble in cold than in 

 hot water. It is not a strong disinfectant, but possesses one 

 advantage over many others in that its potency is not reduced 

 in the presence of serum. For long it held premier position as 

 an antiseptic and disinfectant, and it is to-day used as the unit 

 against which other disinfectants are compared and standardised. 

 Ordinary vegetative bacteria are killed in five minutes in a 3 per 

 cent, watery solution. Its action on sporulating organisms is, 

 however, weak, many hours being required for the destruction 

 of anthrax and tetanus in a 5 per cent, solution at room 

 temperature. Neither carbolic acid nor any of its preparations are 

 suitable for use in food stores, dairies or milking sheds owing to the 

 facility with which milk and other foods absorb its taste and odour, 

 but this objectionable feature applies to other disinfectants of a 

 different class. Alcohol has a marked deterrent effect on the germi- 

 cidal action of phenol, and a solution of carbolic acid in alcohol owes 

 its bactericidal power chiefly to the effect of the alcohol. 

 Crude carbolic acid is, in general, unsuitable for disinfecting 

 purposes owing to the fact that it is but poorly soluble in cold 

 water. 



Compound solutions of cresol are to be preferred to carbolic 

 acid for ordinary disinfection, and, in general, a 2 to 3 per cent, 

 solution will be of sufficient strength; soft water should be used 

 when possible. 



CARBOLIC POWDERS. These consist of crude carbolic acid 

 mixed with a variety of absorbent materials. Carbolic powders 

 are almost inert if made with slaked lime, chalk or any alkali, as 

 the resulting carbolate of lime has practically no disinfecting pro- 

 perties. The best substances to use are gypsum, infusiorial earth 

 (such as Kieselguhr), bricks, peat, sawdust, and almost any cheap 

 non-alkaline substance capable of absorbing the acid without com- 

 bining with it may be used for the purpose. The proportion of 

 carbolic acid should be at least 15 per cent., but Kieselguhr will 

 absorb as much as 30 per cent. In general, carbolic powders should 

 find no place among disinfectants, they merely delay decomposition. 

 The sight of them scattered about and the smell they give off appeals 



