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.
I must not omit to notice the most modern application of gold as a remedy, and that is in its metallic form in "metallo-therapy," as developed mainly in Paris by Charcot and others. It seems that rather a large proportion of nervous patients on the Continent suffer from impaired sensation of one-half of the body, and that by the application of two metals, as a gold and a copper coin over several nerve-trunks, sensation may be "transferred," returning to the affected side in about a quarter of an hour, but often leaving, at the same time, the previously sound side. Such a peculiar circumstance is not yet wholly explained, but has been connected with a gentle galvanic action (Medical Record, 1878-79). Dr. A. Hughes Bennett and others explain the phenomena rather by "expectant attention," and I believe that mental influences of various kinds are a much more likely explanation than any specific properties of metals thus applied.
Fine gold, and the solution of the chloride, are placed in the appendix to the B. P., but no directions for their internal use are given. Pulvis auri: dose, 1/4 to 1/2 gr. gradually increased to 2 to 3 gr. - may be given in pill with confection of roses, but is not a good form. Syrupus auri, containing 24 gr. to the ounce, has been used by way of friction on the tongue, but cannot be depended upon. Unguentum auri, 1/2 dr. to the ounce of lard - not dependable. Chloride of gold and sodium: dose, 1/30 to 1/10 gr. once or twice daily, in-pill - the best preparation, but its irritant and poisonous properties should be remembered. Teroxide of gold: dose, 1/10 gr. twice or thrice daily. Iodide of gold (French codex): dose, 1/15 to 1/10 gr., said to be more active than corrosive sublimate.