The heart-wood of Haematoxylon campechianum, Linné"—(U. S. P.).
COMMON NAME: Logwood.
ILLUSTRATIONS: Woodville, Med. Bot., 17; Bentley and Trimen, Med. Plants, 86.
Botanical Source.—This is a tree of from 20 to 25 feet in height, and occasionally reaching 40 or 50 feet. The trunk or stem is generally crooked and deformed, seldom exceeding 18 inches in diameter, and covered with a rough, ash-colored bark. The branches are somewhat flexuous, terete, and covered with whitish spots; in mountains and moist situations unarmed, but in localities where the tree is stunted in growth, furnished with sharp spines below the leaves. The leaves are alternate, from 2 to 4 from the same irregular, rough, tubercular prominence, pinnate, sometimes dividing, in a bipinnate manner, at the lowest pair of leaflets; the leaflets are 4-paired, shortly stalked, obovate, or obcordate. The flowers are yellow, slightly fragrant, on pedicels ½ inch in length, borne in axillary and subterminal racemes. The calyx is deeply 5-parted, brownish-purple, with thin membranous, deciduous, unequal lobes, and a short, green, campanulate tube. The petals are nearly equal, obovate, wedge-shaped at base, scarcely longer than the sepals, and of a lemon-yellowish color. Stamens 10, alternately short, inserted on the inside of the margin of the persistent tube of the calyx; filaments hairy at base; anthers ovate, without glands. Ovary lanceolate, compressed, 3-seeded, bearing a capillary style, which projects beyond the stamens and petals; stigma capitate and expanded. The pod or legume is flat, compressed, lanceolate, acuminate at both ends, 1-celled, 2-seeded, not opening at the sutures, but bursting in the middle longitudinally (L.).
History and Description.—This tree grows in Jamaica, on the eastern shore of the bay of Campeachy, and in many of the West India Islands. The wood consists of a yellowish alburnum, and a dingy cherry-red inner wood, which last is the part used in medicine and the arts; it forms a useful commercial commodity, and is extensively used as a dye-stuff. It becomes darker-colored by exposure. Water or alcohol extracts its coloring matter, forming deep-purple solutions. Its aqueous solution yields a fine blue precipitate with lime-water, alum, and acetate of lead; a deep violet-blue with the higher salts of iron, and curdy flakes with solution of gelatin, sulphuric, nitric, hydrochloric, and acetic acids, and sulphate of copper also produce precipitates. Water is the menstruum usually employed to extract its virtues. A pound of the wood yields about 2 ounces of the extract. The medicinal article is thus described in the Pharmacopoeia:
"Heavy, hard, externally purplish-black, internally brownish-red, and marked with irregular, concentric circles, splitting irregularly; odor faint, agreeable; taste sweetish, astringent. When chewed, it colors the saliva dark pink. Logwood is generally met with in the form of small chips or coarse powder of a dark brownish-red color, often with a greenish luster"—(U. S. P.).
Mr. Louis Siebold (Brit. Pharm. Conf., 1887, [see Amer. Jour. Pharm.]), considers the logwood of San Domingo and Jamaica inferior to that of Campeachy or Honduras, and points out the great chemical difference between the commercial wood sold in logs, and that which comes to us ground or in chips, for the latter has mostly undergone a process of fermentation during which it is considerably modified, and loses its sweet taste. However, for the purpose of testing water for traces of metals by means of logwood extract (see below), the fermented wood is preferable.
Chemical Composition.—Besides the usual plant constituents, logwood contains tannin (3.5 per cent, according to Chas. F. Kramer, Amer. Jour. Pharm., 1882, p. 388); phlobaphenes (which are coloring matters produced by decomposition of tannin substance), and haematoxylin or haematin. The latter body was discovered by Chevreul in 1811, and obtained pure in 1842 by Erdmann. Commercial logwood extract often contains from 9 to 12 per cent of this principle which frequently crystallizes therefrom spontaneously in long needles. It is obtained by extraction with aqueous ether and crystallization from hot water containing reducing agents, e. g., sulphurous acid or acid sulphites.
Haematoxylin (C16H14O6, Erdmann), crystallizes with 3 molecules of water in the quadratic, with 1 molecule, in the rhombic system. It is not easily soluble in cold, but readily dissolves in hot water, alcohol, and in salts of alkaline reaction, e. g., borax; from the latter solutions it can not be obtained crystallizable unless the solution is slightly acidified. Haematoxylin is very sensitive to light and air, turning reddish when exposed to light. When exposed to moist air or other oxidizers, it rapidly deliquesces, turns brown, and finally yields a colorless mass containing oxalic acid. By milder oxidation it is converted into haemateïn. Solution of haematoxylin yields a black violet precipitate with ferric salts (ink), and is also precipitated by solutions of other metallic salts. The precipitates with lead and copper salts turn blue upon exposure to the air. When subjected to destructive distillation haeematoxylin yields pyrogallol and resorcin; accordingly, a purple-colored phtalein (see Aniline Dyes), has been prepared by the interaction of 2 molecules of haematoxylin and 1 molecule of phtalic anhydride (E. A. Letts, Berichte, 1879). Haematoxylin undergoes a remarkable change with ammonia water in the presence of air. It is dissolved with rose-red, then purple-red color. The solution, by absorbing oxygen from the air becomes blackish-red, and upon evaporation, yields violet prismatic crystals of haematein-ammonia (C16H12O6.2NH3). These are soluble in water and alcohol. When heated to 130° C. (266° F.), ammonia is given off and haematein (C16H12O6), is formed. Acetic acid likewise precipitates it from the aqueous solution of its ammonia compound. Another method of obtaining it is to add a few drops of nitric acid to an ethereal solution of haematoxylin. It forms a dark-violet, crystalline powder, soluble with difficulty in alcohol and glacial acetic acid, insoluble in chloroform and benzol. It dissolves at 20° C. (68° F.), in water at the rate of 6 in 10,000, and is about twice as soluble in ether. In alkalies it dissolves with blue color, which changes to brown. Haematoxylin has been proposed as a delicate test for ammonia; the presence of 1/1,000,000 part of ammonia in water is indicated by an orange-red color assumed by blotting paper saturated with an alcoholic solution of haematoxylin (see Husemann and Hilger, Pflanzenstoffe). Arthur Weddell likewise recommends haematoxylin as a delicate test for calcium bicarbonate in water, and for the presence of lead (1 in 200,000), in the same medium, by the characteristic color reaction which takes place in the presence of air (Amer. Jour. Pharm., 1884, p. 214). L. Siebold (Amer. Jour. Pharm., 1887, p. 526), was able to detect even much smaller quantities of metals in potable water by this method. For the application of haematoxylin as an indicator in alkaloidal assay, see Proc. Amer. Pharm. Assoc., 1896, p. 109.
Action, Medical Uses, and Dosage.—Logwood is a tonic and unirritating astringent, less constipating than many other astringents, and is useful in hemorrhages from the uterus, lungs, and bowels, in old diarrhoeas and dysenteries, in summer complaint of children, and in night-sweats. A favorable preparation with many of the older practitioners in cholera infantum, after a proper employment of the syrup of rhubarb and potassa, is the following: Dissolve 2 drachms of extract of logwood in 4 fluid ounces of boiling water, to this solution add 2 fluid drachms of ammoniated tincture of opium, 3 fluid drachms of tincture of catechu, 1 fluid drachm of compound spirits of lavender, and 4 fluid ounces of simple syrup, or syrup of ginger. The dose is a teaspoonful every 3 or 4 hours. An infusion of logwood taken internally, and also used locally, in form of spray or injection, has effectually cured several cases of obstinate and offensive ozoena. In constitutions broken down by disease, dissipation, or the excessive use of mercury, the decoction of logwood, used freely in connection with the other treatment, will be found highly beneficial. Dose of the decoction, from 2 to 4 fluid ounces; of the extract, 5 to 30 grains. The use of logwood imparts a blood-red color to the stools and the urine. It should never be combined with chalk or lime-water, as they are incompatibles.
Related entry: Brazil wood
Red Ink.—A good red ink may be made as follows: Take of pernambuco wood, a Brazilian wood said to be derived from Caesalpinia echinata, 4 ounces; diluted acetic acid, distilled water, of each, 16 ounces; boil together until 24 ounces remain. Then add 1 ounce of alum, evaporate the liquid to 16 ounces, dissolve 1 ounce of gum Arabic in it, strain, and to the cold liquid add 1 drachm of chloride of tin. This ink is preferable to the cochineal ink, being free from its bluish tint and more permanent.