It is obvious that of primary importance in making medicinal or medicated soaps is the employment of a pure base. However effectual as a remedy for skin diseases the medicinal soap might be, the presence of an impure and alkaline base is almost sure to cause roughness and desquamation (the formation of scale) on the skin. Medicinal soaps of good quality are prepared with Voiry's plain cocoanut oil paste soap as a base. This is made as follows. 12 parts by weight of cocoanut oil are boiled in a porcelain dish with 8 parts of soda lye (10° B.); to the cream thus obtained, add 5 parts of soda lye (20° B.), and arrest the boiling when a sample placed on a cold body becomes solid. Add a quantity of distilled water, bring again to the boil, and add 5 parts of common salt. The soap is separated by decantation after cooling, cleansed by washing twice in a 20 per cent, solution of ordinary salt, and after-wai'ds in cold distilled water. The excess of water is squeezed out, and a plain paste soap is the product. The first medicinal soaps made contained tar, and were neither pleasant looking nor agreeable to use, but for all that they were useful and effective.

Recipes for tar soaps are:

(1) Beat together 1 part of tar, 2 parts of liquor potassa, and 2 parts of soap in shavings.

(2) Make up in the usual way 41b. of cocoanut oil, 21b. of tallow, 1 lb. of juniper tar, and 3 lb. of soda lye (40° B.). For a vaseline tar soap, saponify 401b. of cocoanut oil and 61b. of tar with 221b. of lye (40° B.). Melt 41b. of yellow vaseline, and stir into it the soap, with the addition of l1b. of lukewarm water.

(3) Rub up 1 part by weight of tar with 9 parts of Voiry's paste soap.

Possessing the good qualities of tar, and but few of its pronounced disadvantages for use in medicinal soap, is carbolic acid. A soap containing as much as 25 per cent, of this can be used for the hands, but is not suitable for general use. Even carbolic soap, though an improvement on tar soap, is not an ideal material, as it has a strong odour. Recipes for carbolic soaps are:

(1) Melt 201b. of half-palm soap and add lib. of starch, and mix thoroughly; then add 1 oz. of carbolic acid in crystals, 2oz. of oil of lavender, and loz. of oil of cloves.

(2) Incorporate in a warm mortar 75 parts of powdered stearin soap with 25 parts of pure carbolic acid, and press the product into tablets.

(3) Melt 150 parts of fresh cocoanut oil soap, and add 10 parts of a solution of alcohol, 6 parts of carbolic acid, 2 parts of caustic potash, and 1 part of oil of lemon. Stir thoroughly, and pour into moulds.

(4) Dissolve 2 parts by weight of white carbolic acid in 1 part of 93 per cent, alcohol, and gradually rub up with 38 parts of Voiry's paste soap.

Salol enters into the composition of many soaps, and especially into shaving soaps, suggested as a remedy for and preventive of sycosis para-sitaria, a disease contracted at barbers' shops from razors and accessories. In making salol shaving soap the base is prepared first, l1b. of beef suet is melted with 41b. of cocoanut oil and allowed to cool to 120° F.; after adding 14 oz. of 18 per cent, caustic soda solution and 2Aoz. of 24 per cent, caustic potash solution, the mass is stirred at a gentle heat for half an hour, or until it is homogeneous. Perfume is added consisting of 40 minims of oil of caraway, 50 minims of oil of bergamot, 30 minims of oil of lavender, 20 minims of oil of thyme, and 0 drops of essence of mirbane. While the mass is still warm, loz. of finely powdered salol is added, and the whole is heated to 113° F., at which temperature the antiseptic melts; it is stirred thoroughly the while. When cold the soap is cut up as desired, dried partially in the open air, and, for preference, wrapped in tinfoil. To make a salol soap powder, mix together 35 oz. of finely powdered stearin soap, 1 grain of coumarin, 5 drops of oil of bergamot, and 2 drops of oil of winter green; mix 21b. of this base with loz. of finely powdered salol.

Mercurial soap is made by saponifying mercurial ointment; thus 10 oz. of mercury are mixed thoroughly with 2 oz. of mercurial ointment until the globules are not visible with a lens, and then 18 oz. of powdered soap and 2 oz. of lard are added. Do not place mercurial soaps in contact with metals. Other recipes for mercurial soaps are:

(1) Beat up to a uniform mass in a mortar 1 drachm of corrosive sublimate, 1 fluid ounce of rectified spirit, and loz. of powdered white castile soap; add a few drops of attar of roses or a mixture of the oils of cassia and bitter almonds.

(2) Dissolve 1 part by weight of sublimate in 16 parts of alcohol, filter, and rub up with sufficient of Voiry's paste-soap.

(3) Beat up into a smooth mass 1 lb. of white castile soap and 1/2oz. of protochloride of mercury dissolved in 4oz. of alcohol.

Ichthyol Soap

Ichthyol Soap is used in the treatment of eczema and rosacea, and reduces redness of the skin; it may contain as much as 5 per cent, of the sodium sulphichthyolate. Boracic soap containing borax or boric acid has many desirable qualities; the soft kinds are made thus:

(1) Add a borax solution to the ordinary soft-soap ingredients either before or after manufacture.

(2) Dissolve by heat any ordinary soft soap in a borax solution, and when cold thoroughly incorporate the two.

(3) Either by beating up in a mortar or by the aid of gentle heat, incorporate 1 oz. of borax with 1 lb. of new Windsor soap.

(4) Add 101b. of soda lye (15° B.) to 101b. of molten white fat till a clear liquid is formed, and then add 61b. of potash lye (10° B.) and l 1/2 lb. of borax solution to produce a semi-solid translucent paste.

(5) For a harder soap rub up in a mortar equal parts of sodium borate and Voiry's paste soap and press to the shape required.

Sulphur Soaps

Sulphur is made up into many soaps, the best of which contain about 10 per cent, of very finely divided sulphur, and are perfumed, as when used alone sulphur gives soap a rather unpleasant smell. Various combinations of tar, naphthol, iodides, etc., with sulphur are employed also. Recipes for sulphur soaps are:

(1) Beat to a smooth mass in a mortar 8oz. of freshly made white curd or castile soap, 1 oz. of levigated flowers of sulphur, 1 fluid oz. of rectified spirit, tinted by infusing alkanet in it, and add a few drops of attar of roses.

(2) For camphorated sulphur soap, dissolve 4 parts (by weight) of camphor in 300 parts;of molten cocoanut oil, saponify with 150 parts of soda lye (38° B.), and add 25 parts of potassium sulphate dissolved in 13 parts of water.

(3) Rub up in a mortar P part (by weight) of sulphur with 9 parts of Voiry's paste soap and press to shape. Thiosavonal is a new kind of soft sulphur soap (soluble in water), in the preparation of which sulphurised oils are used.

Grube's Formula

Grube's Formula is: Make fluid the thick thio oil by adding alcohol, and stir in an equal bulk of potash lye, also thinned with alcohol. The addition of large quantities of potash lye at one time produces separation of the sulphur, but the danger lessens towards the end of saponification. At last a small excess of potash lye is added. If the liquid is quite clear, and if a sample is soluble both in water and in alcohol, all the thiosebacic acid has saponified. Neutralise the excess of alkali by adding volatile fatty acid and free the resultant soap solution from alcohol in a steam bath, and boil down to the consistency of soft salve, occasionally testing for neutrality; 85 parts of this are mixed with 15 parts of glycerine. A liquid thiosavonal or sulphur soap may be made by boiling down the soap solution as obtained above to the consistency of ss'rup instead of to a salve, 88 parts then being mixed with 12 parts of glycerine.