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.
As a matter of convenience the bath may be prepared with six fluid ounces of the dilute nitro-hydrochloric acid added to each gallon of water in a wooden or porcelain vessel, but the more active formula of Sir R. Martin is the following: - Acid. nit. fort. 3 ij., Acid. hydrochloric. fort. 3 iij.; mix and allow to remain together for at least twelve hours; afterward add 5 oz. of water. Of this mixture 3 oz. should be used for each gallon of water: two gallons are an average quantity for a foot-bath. The bath may be kept in use for several days by adding 1/2 oz. of acid solution and 1 pint of water each time to compensate for evaporation, warming only as much as is necessary (96° to 98° F.). The towels and sponges used should be kept in cold water during the interval.
[Preparations, U. S. P. - Acidum nitro-muriaticum: nitric acid, 3 troyounces; muriatic acid 5 troyounces. Acidum nitro-muriaticum dilutum: nitric acid 1 1/2 troyounce, muriatic acid 2 1/2 troyounces; distilled water, sufficient to make 1 pint.]
Chiefly sulphuric and hydrochloric acids.