1 Spec. Plant Willd. ii. 547.

Cl. 10. Ord. 1. Decandria Monogynia. Nat. ord. Leguminosae.

G, 830. Calyx five-parted. Petals five. Capsule lanceolate, one-celled, two valved, with the valves boat-shaped.

Species 1. H. Campechianum. The Logwood tree. Med. Pot. 3d ed. 455. t. 163.

Officinal. HAematoxylum, Lond. HAematoxyli lignum, Edin. Dub. Logwood.

Syn. Bois de Campeche (F.), Kampesch-holz, Blauholz (G.), Campechehout (Dutch) Campeschetrace (Dan.), Campechetrad (Swed.), Campeggio (I.), Palo de Campeche (S.), Pao de Campeche (Portug.).

This tree is a native of South America, and attains to great perfection at Campeachy, in the bay of Honduras. It was introduced into Jamaica in 1715, and from its quick growth now abounds in a degree which much incommodes the landholders in the neighbourhood of Savannah la Mar; flowering in March and April.2 The stem and branches are generally crooked; the former is seldom above twenty inches thick; and , the tree scarcely ever rises more than twenty-four feet in height. It is covered with a dark-colouredrough bark; and has many smaller ramifications, which are close, prickly, and beset with strong spines. The leaves are abruptly pinnate, each composed of four or five pairs of sessile, obcordate, obliquely nerved leaflets. The flowers are in terminal, spicular clusters; the calyx consists of brownish purple-coloured, oblong, obtuse segments; the petals are spreading, obtusely lanceolate, and of a reddish yellow colour. The stamens are downy, tapering, shorter than the corolla, with small oval anthers; the fruit is a double-valved pod, containing five or six small, flat, reniform seeds.

Logwood is brought to this country in logs, which are afterwards chipped. Those pieces which have a deeper colour are to be preferred. It is much employed as a dye-wood.

Qualities.-This wood is inodorous, but has a sweet astringent taste: it is hard, compact, heavy, and of a deep red colour, which it gives out both to water and alcohol. The recent infusions made with distilled water are yellow, but those with common water have a reddish purple colour, which is deepened by the alkalies, and changed to yellow by the acids.

1 From blood, and wood----Millar's Dictionary. The trivial name Cainpechianum, and the English term Campechi wood, originated from Palo Campechio, the name imposed by the Spaniards who first discovered the wood.

2 It was cultivated in this country by Mr. Millar in 1730; but is now seldom found in our hothouses.

They form precipitates with the sulphuric, nitric, hydrochloric, and acetic acids, solutions of alum, sulphates of iron and of copper, acetate of lead, and tartarized antimony 1; which are, therefore, incompatible in prescriptions with these infusions and decoctions. The colour of the precipitates varies : those with the acids are reddish brown; with alum and tartarized antimony, violet; with sulphate of iron, bluish black; sulphate of copper, purplish blue; acetate of lead, reddish black; and sulphate of magnesia, purple. According to Chevreul, logwood contains a volatile oil, tannin, two kinds of colouring matter, - one of which is soluble both in water and alcohol, the other soluble in alcohol only, - acetate of lime and of potassa 2, and a peculiar substance, which is procured in small brilliant crystals of a reddish white colour, and a slightly astringent, bitter, and acrid taste; and which he named hematin. It is procured by digesting rasped logwood in water of the temperature 125°, filtering, and evaporating to dryness: then digesting the residue for a whole day in alcohol of sp. gr. 0.837, filtering, and concentrating by evaporation; a small portion of water is then to be added, and the evaporation being carried a little farther, it is to be left to crystallize.

Crystals of hematin are formed in abundance.

Medical properties and uses.-Logwood is supposed to be astringent: but this is a questionable opinion; for although it produces an ink with sulphate of iron, it possesses no acerbity, and does not produce a precipitate with gelatine.3 It is employed in diarrhoea, and in the latter stage of dysentery; but the extract is more usually ordered. It has the advantage of giving tone to the general system, and thus obviates the lax state of the intestines. When taken into the stomach, it imparts a red colour to the urine in twenty-five minutes after it is taken. The decoction may be taken in doses of two or three fluid ounces, frequently repeated.

Officinal preparation.-Extraction Haematoxyli, L.