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.
Under sulphur it has been stated that the local application of that remedy is not desirable (v. p. 30), but sulphurous acid acts very much better, and is, as a rule, well borne, and even liked by the patient.
Dr. Dewar and Mr. Pairman used it rather in fumes and spray or gargle, and conjoined with it iron or chlorate of potash. Dr. Joyce (quoted by Dr. Geo. Johnson, Lancet, i., 1875, p. 82) had the best results from the same practice (with iron). Fergus depends on the acid with ice only, and other observers have had satisfactory results from the salts: thus Dr. Hayden from the hyposulphite (Dublin Quarterly, August, 1866). I think the local application of the acid in spray highly desirable.