External

The ointment official in B. P., 1 part of the acid to 9 of hard, and 18 of soft paraffin may be used when an antiseptic stimulating ointment is required. A collodion composed of salicylic acid, 1; flexible collodion, 8; or a glycerin containing 10 per cent. of salicylic acid; or a plaster, also 10 per cent., are good preparations. Strong applications of salicylic acid are very useful for removing excess of epidermis, warts, or corns because it softens epithelium. Salicylic acid, 11; extract of cannabis indica, 2; flexible collodion, 87 parts, form an excellent remedy (commonly known as green solution) for corns. Powdered salicylic acid mixed with starch or chalk may be employed to check profuse perspiration of the feet and axillae. The German Pharmacopoeia has for this purpose a Pulvis Salicylicus cum Talco (salicylic acid, 3; wheaten starch, 10; talc, in powder, 87). The sweats of phthisis may be treated in the same way. A little salicylic acid is often added to Thompson's fluid {see p. 275). Salicylic acid is the principal ingredient in Thiersch's solution. For this formula see p. 275.

Internal

Salicylic acid is a specific for many cases of rheumatic fever; it lowers the temperature, lessens the swelling, leads to a rapid cessation of pain, and may diminish the liability to pericarditis and other complications. It must be given well diluted to prevent dyspepsia. The sodium salt is often preferred as being the most soluble, but in order to diminish the risk of salicylism it should be prepared either from pure artificial or from natural salicylic acid. If the attack is severe, 20 gr. 1.20 gm. every two or three hours should be given for the first twelve or twenty-four hours; then, if the patient is doing well, the frequency of the dose may be gradually diminished, but it should be continued thrice daily for ten days after the temperature is normal and the pain has ceased. Salicin is not so powerful as sodium salicylate, but it is said to be less depressant than the synthetic acid.

These preparations are of no use for gout or severe osteoarthritis, but occasionally the pains of chronic rheumatism are relieved.

Salicylic acid or salicin may produce a fall of temperature in any fever, but, as we have more certain antipyretics, they are not used except for rheumatic fever. Some writers have found salicylic acid useful in migraine, sciatica, diabetes, and diphtheria, but it is probably of little value for these disorders. The action of the salicylates in eliminating uric acid explains their usefulness in migraine and sciatica which is incontestible in some cases. So far as they limit intestinal fermentation they are beneficial in the treatment of diabetes. For the glycosuria of patients afflicted with gout or goutiness they are useful. Salicylic acid has been given to render the urine acid in cases of alkaline urine and cystitis, but there are better remedies for this purpose. It has also been given in cases of gallstone with the object of rendering the urine less viscid.

Aspirin (not official) is acetyl salicylic acid, which occurs as a white, insoluble, crystalline powder, or in needles, of an agreeable taste. In an alkaline fluid it breaks up and sets free salicylic acid. It has been employed for acute polyarticular rheumatism in the same doses as sodium salicylate, over which it is believed to possess the advantage of not deranging digestion.