This section is from the book "Materia Medica And Therapeutics: An Introduction to the National Treatment of Disease", by John Mitchell Bruce. Also available from Amazon: The pharmacology and therapeutics of the materia medica.
Characters. - A powder or in small pieces of a light yellow colour, becoming pale-brown by exposure; mixed with small pieces of wood.
Composition. - Goa powder contains 80 per cent. of chrys-arobin, C3oH16O7, which is converted into chrysophanic acid, by the process presently to be given.
From Goa Powder is prepared:
Acidum Chrysophanicum. - Chrysophanic acid C41Hl0O4. Made by exhausting Goa powder with hot Benzol, filtering, allowing Chrysarobin to crystallise out, dissolving this in strong Potash, and decomposing with a mineral acid. It may also be obtained from Rhubarb. See Rhei Radix, page 318.
Dose. - 1/10 to 2 gr.
Unguentum Acidi Chrysophanici. - Unguen-tum Chrysarobini (U.S.P.). 1 in 10 of benzoated lard.
Externally. - Goa powder or chrysophanic acid destroys low vegetable organisms in connection with the skin, stains it yellow, and stimulates it so much as to produce in some in-stances serious constitutional disturbance. It is a successful application in some forms of ringworm, and in scaly diseases of the skin, especially psoriasis.
Internally. - Chrysophanic acid is apt to cause vomiting and purging.
Chrysophanic acid has been given with various degrees of success in psoriasis, apparently by a remote local action on the skin.
Senna Alexandrina - Alexandrian Senna. - The leaflets of Cassia lanceolata and Cassia obovata, imported from Alexandria; carefully freed from the flowers, pods, and leaf stocks of the same, and from the leaves, flowers, and fruit of Solenostemma Argel.
Characters and Tests. - Lanceolate or obovate leaflets, about an inch long, unequally oblique at the base, brittle, greyish-green, of a faint peculiar odour, and mucilaginous sweetish nauseous taste. The unequally oblique base, and freedom from bitterness, distinguish the senna from the argel leaves, which, moreover, are thicker and stiffer.
Impurities; and substances resembling Senna: Solenostemma Argel, Uva Ursi, and Barosma, all equal at the base.