Soap. - Sodium Oleate, NaC18H33O2. Synonyms. - White Castile Soap, Hard Soap.


Soap is prepared from Soda and Olive Oil. C3H5(C18H33O2)3+ 3NaOH=2NaC18H33O2 (Hard Soap)+C3H5(OH)3 (Glycerin).


A white or whitish solid, hard, yet easily cut when fresh, having a faint, peculiar odor free from rancidity, a disagreeable, alkaline taste, and an alkaline reaction.


Soluble in water and in Alcohol, more readily with the aid of heat.

Soap is contained in Pilulae Aloes, Pilulae Aloes et Asafoetidae, Pilulae Asafoetidae, Pilulae Opii, and Pilulae Rhei.


1. Emplastrum Saponis. - Soap Plaster. Soap, 100; Lead Plaster, 900; by solution in Water and evaporation.

2. Linimentum Saponis. - Soap Liniment. Synonym.-Opodeldoc. Soap, 70; Camphor, 45; Oil of Rosemary, 10; Alcohol, 750; Water to 1000.

Soap Liniment is contained in Linimentum Chloroformi.

Sapo Mollis. Soft Soap. Sapo Viridis. Green Soap

Potassium Oleate. Synonyms. - Sapo Viridis. Green Soap. A soap prepared from Potassa and fixed oils, generally from Olive Oil.


By heating Linseed Oil, 400; adding to this Potassa, 90; dissolved in Water, 450; and Alcohol, 40; until the mixture is soluble in boiling Water without the separation of oily drops.


A soft, unctuous mass, of a yellowish-brown or brownish-yellow color.


In about 5 parts of hot Water to a nearly clear liquid; also in 2 parts of hot Alcohol, without leaving more than 3 per cent. of insoluble residue.


Linimentum Saponis Mollis. Liniment Of Soft Soap. Tinctura Saponis Viridis

Synonym. - Tinctura Saponis Viridis. Soft Soap, 650; Oil of Lavender Flowers, 20; Alcohol, 300; Water to 1000. By filtration.

Uses Of Soap

Hard soap may be used for medicated soaps. The prescriber should state the percentage of the drug, e.g., ichthyol, tar, sulphur, he wishes the soap to contain. The dispenser planes the soap into thin shavings, dries them at 100° F. 37.8° C., powders them in a mortar, then thoroughly mixes and beats up the soap powder, the drugs, and one part of alcohol (60 per cent.) to 8 parts of soap powder. The whole is put into a soap press and stamped. Soaps are used for cleansing. The plaster is protective against bed-sores. The liniment is used as a cutaneous stimulant. That of soft soap is employed for psoriasis, lichen and eczema. Hard soap forms a basis for many pills. Either soap is frequently made into a lather with about a pint 500. c.c of water at 100° F. 37.8° C and used as a purgative enema. Soft soap is much preferred; about 1 fl. oz. 30. c.c is commonly used. All enemata, but perhaps especially those made with hard soap, may produce an erythematous rash, probably due to the solution and consequent absorption of some faecal toxin.