This section is from the book "Materia Medica And Therapeutics Inorganic Substances", by Charles D. F. Phillips. Also available from Amazon: Materia medica and therapeutics.
Dr. Gee has found advantage from a lotion containing 1/2 oz. of sulphocyanide of potassium in 7 oz. of water with 1 oz. of glycerin, kept applied to the scalp. The effect must be watched, and a daily washing with soap and water practised.
Hydrocyanic acid has a certain value in relieving spasmodic pain and irritation, but its use is limited by the extreme care required in dosage, and the risk of causing unpleasant symptoms; yet to say with Trousseau that "it is often dangerous, almost always useless, and very rarely curative," greatly overstates the facts.