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.
Soda baths are also useful in relieving pains of rheumatic character in the joints and muscles. Basham recommended basic phosphate of soda in powder as a good application for enlarged and painful gouty joints (Medical Times, ii., 1848), and it has some advantage over liquid applications; it may be applied on moistened spongio-piline. Hot salt in flannel is often a convenient mode of applying warmth to rheumatic or painful parts: in similar cases Dr. H. Bennett used "soda poultices" (Times, ii., 1853, p. 502).1