A concretion from clefts in the stem of Andira Araroba (Angeliun Amar-gosa) imported from Brazil chiefly into India. (Not officinal)

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.

Characters. - A dull orange-yellow powder, or shining yellow needles, odourless, with an acrid taste; insoluble in water, and spirit; soluble in hot benzol, oils, and vaseline.

Dose. - 1/10 to 2 gr.

Preparation.

Unguentum Acidi Chrysophanici. - Unguen-tum Chrysarobini (U.S.P.). 1 in 10 of benzoated lard.

Action And Uses. 1. Immediate Local Action And Uses

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.

2. Action On The Blood; Specific Action; And Remote Local Action And Uses

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.