"Medicated Soaps. - These substances which have been made both by chemists and by manufacturers, may be employed with advantage in the treatment of psoriasis as well as of many other cutaneous affections. A great argument for the use of soap as a vehicle is undoubtedly the fact that that substance is so easily and so conveniently applied; and the potass (or soda) and fat which these medicated soaps contain, so far from interfering with their efficacy, very frequently promote it by softening the epidermis. A variety of medicinal substances, among which are iodine, iodide of potassium, sulphur, iodide of sulphur, tar, graphite, benzoin, Carlsbad salt, etc., have been introduced into such soaps. Efforts have also been made to increase their good effects by the addition of glycerine, and to give some of them a fluid form.

"I have repeatedly made use of these medicated soaps in every variety of cutaneous disease. But, although I cannot mention anything as especially contraindicating their employment, I have found very few of them to possess the efficacy which their inventors and makers would like to claim for them. The most important among them are those which contain sulphur, iodide of sulphur, or tar. The last of these is particularly to be recommended in cases of psoriasis, and therefore I shall refer to it again, and in the next paragraph, when I am speaking of tar as a remedy in this disease, I shall give the indications for the use of tar-soap, and the mode of applying it.