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.
The patient should be prepared for a course of mercurial inunction by simple dieting and by warm baths: and during it should be clothed in flannel and avoid exposure. When making the frictions himself, he should rub thoroughly in his hand the prescribed quantity of ointment, and then slowly and forcibly anoint certain parts of the body in a definite order: it is usual to choose the axillae and the groins, but practically it is better to avoid parts with abundant hair-follicles. According to the German method of Zeissl, the inner side of both upper arms is first treated, on the next night the inner side of the thighs, then of the forearms, then of the legs, afterward of the groin and of the back, so that an interval of several days is allowed between the friction of any one part, in order to avoid local soreness. The evening is the best time for the application, and warmth promotes its effect: the part should be kept covered during the night, and be cleansed on the following morning. When the patient is too ill, or for any reason is unable to apply the ointment himself, the attendant who uses it should protect his own hand with a leather or caoutchouc glove. In young children frictions are often made on the inner side of the soles of the feet, or a piece of ointment is simply placed on the inner side of a thin flannel binder. For adults, 1/2 dr. up to 2 dr. represents an average amount of mercurial ointment for daily use; but sometimes, as in peritonitis, 1 dr. has been ordered every hour: it is important that no rancid ointment be used, or severe irritation may be induced by it. This method of treatment has the advantage of saving the digestive tract from any direct irritation from the drug, and, according to Sir B. Brodie, "it cures better and injures the constitution less." This, however, scarcely holds true in view of the modern cautious admin istration of mercury, and the method of inunction is less often adopted than formerly, since it is, at the best, troublesome and uncleanly.
The endermic application of mercury is effected by dressing a blistered surface with blue ointment or sometimes with calomel. From the latter, purging has resulted, but, as a rule, the endermic method is employed for a local stimulating action on the absorbents, as in pleuritic, pericardial, or joint effusion, rather than to affect the general system.