This section is from the book "An Experimental History Of The Materia Medica", by William Lewis.
Lignum Campechense Pharm. Lond. & Edinb. Lignum campefcanum & lignum indicum Mont. exot. Lignum campechianum species quaedam brasil Sloan. Lignum sappan quibusdam. Campeachy wood or Logwood: the wood of a prickly pod-bearing tree (Hamatoxylum Campechianum Linn,) a native of Campeachy, in the bay of Honduras; from whence the wood is brought over in large compact hard logs of a red colour.
(a) Observ. physico-chym. lib. i. obs. 4.. Not. ad Poterium, 487. De medicament, balsamic. §15.
Refina ligni aloes Ph, Paris.
This wood, imported from America as a dying drug, has of late been introduced into medicine, and found to be a very useful re-stringent and corroborant, in diarrhoeas, dysen-teries, and other disorders from a laxity of the solids. It has a sweetish subastringent taste, and no remarkable smell: extracts made from it, by water and spirit, have a great degree of sweetness, mixed with a mild grateful aftrin-gency. It gives a deep purplish red tincture both to watery and spirituous menstrua * (a); and frequently tinges the stools, and sometimes the urine, of the same colour: of this the patient ought to be apprised, that he may not be alarmed by judging the colour of the discharge to be owing to blood.
Watery menstrua readily extract part of the virtue of this wood, but are very difficultly made to take up the whole. To promote the extraction, the wood should previously be reduced into fine powder, which is to be strongly boiled in the water, in the proportion, for example of a pound to a gallon, till half the liquor is wasted: the powder will still give a considerable impregnation to the same quantity of fresh water, and this repeatedly for four or five times or oftener: the extract obtained by infpiffating the decoctions, of a dark blackish colour in the mass, tinges water of a fine red, like that of the liquors before infpiffation, but does not totally dissolve: it is given in doses of from ten grains to a scruple and upwards. Rectified spirit takes up more from the logwood than watery menstrua. Some digest the powdered wood in four times its weight of spirit, and aftewards boil it in water: the matters taken up by the two menstrua are then united into one extract, by infpiffating the watery decoction to the consistence of honey, and then gradually stirring in the infpiffated spirituous tincture.
* (a) Pure rain water acquires only a deep orange or mahogany colour from logwood; and rectisied spirit a fine yellowish red. The purple hue seems to be communicated by some extraneous saline matter, as the felenitic or aluminous salts in hard spring water. A very small quantity of fixed alkali will also give it slill more perceptibly.