Carbolic Acid

Carbolic Acid, also known as Phenol and Creasote, is a hydroxy derivative of Benzene (q.v.). It is chiefly obtained from heavy coal-tar oil by treating with soda, and then adding an acid to the soda solution. When pure it forms colourless needles, melting at 42ñ, but it soon becomes coloured. It has weak acid properties, a characteristic odour, a burning taste, and is poisonous.

Carbolic acid is extensively employed as an antiseptic and disinfectant. The surgeon uses it for cleansing instruments and sponges, and as a stimulating and antiseptic lotion in the treatment of ulcerated surfaces. If applied to infected matter with the object of destroying germs, the solution must be of suitable strength. As ordinarily employed, carbolic acid is often well-nigh useless. It is a common practice to add a small quantity of a 5 per cent. solution to a large volume of noxious material, the resulting strength of the mixture being absurdly insufficient for the production of the germicidal effect which it is desirable should be obtained. It is sometimes accidentally swallowed and gives rise to symptoms of irritant poisoning; it may be absorbed from wounded surfaces, and in such cases a peculiar discoloration of the urine has been noted (carboluria).