Cathartic acid and chrysophanic acid enter the blood, pass through the tissues, and are excreted by the kidneys and mammary gland; the cathartic acid purging infants at the breast, the chrysophanic acid staining the urine yellow. Senna purges animals when injected into the veins.

Haematoxyli Lignum - Logwood. - The sliced heart-wood of Hsematoxylum Campechianum. Imported from Campeachy, Honduras, and Jamaica.

Characters. - The logs are externally of a dark colour, internally they are reddish-brown. The chips have a feeble agreeable odour, and a sweetish taste. A small portion chewed imparts to the saliva a dark pink colour.

Composition. - Logwood contains tannic acid, and a peculiar colouring principle, haematoxylin, C10H14O6, occurring in colourless crystals, which become red on exposure to light, the solutions undergoing various changes of colour with acids and alkalies, and coagulating gelatine. The decoction precipitates perchloride of iron violet blue, acetate of lead and other metallic salts a beautiful blue. Other less important substances occur in logwood.

Incompatibles. - Mineral acids, metallic salts, lime-water, and tartar emetic.

Preparations.

1. Decoctum Haematoxyli

Decoctum Haematoxyli. 1 in 20. Dose, 1 to 2 fl.oz.

2. Extraction Haematoxyli

Extraction Haematoxyli. Aqueous. Dose, 10 to 30 gr.

Action And Uses

Haematoxylum possesses the astringent action of tannic acid, and may be used in the same class of cases. See Galla.