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. Elliotson, in a special treatise on the subject, makes several groups of cases in which he found prussic acid extremely useful; some were marked by pain and tenderness only, others by flatulence, nausea, anorexia, liver-troubles, and vertigo, others again by pyrosis, heartburn, and palpitation (Medico-Chirurgical Review, i., 1821). A. T. Thompson made somewhat similar observations, especially noting benefit when the tongue was hot, red, and sore (Dispensatory). Bailey also published illustrative cases (London Medical Repository, 1828), and alluded to its value when there was sympathetic heart-disturbance, palpitation, etc. In such cases, it is still in frequent use, although other remedies may be required if there be marked symptoms of unhealthy secretion. Disappointment as to its effects may be sometimes traced to the inertness from age of the preparation, or to admixture with other drugs.