The lignum vitae of commerce, so named on account of its high repute as a medicinal agent in past times, when also it was known as lignum sanctum and lignum Indicum, lignum guaycanum, or simply guayacan, is procured from G. officinale, and in smaller amount from G. sanctum. It is exported in large logs or blocks, generally divested of bark, and presents in transverse section very slightly marked concentric rings of growth, and scarcely any traces of pith; with the aid of a magnifying glass the medullary rays are seen to be equidistant and very numerous. The outer wood, the sapwood or alburnum, is of a pale yellow hue, and devoid of resin; the inner, the heartwood or duramen, which is by far the larger proportion, is of a dark greenish-brown, contains in its pores 26 per cent, of resin, and has a specific gravity of 1'333, and therefore sinks in water, on which the alburnum floats. Owing to the diagonal and oblique arrangement of the successive layers of its fibres, the wood cannot be split; and on account of its hardness, density, and durability it is much valued for the manufacture of ships’ pulleys, rulers, skittle-balls, mallets, and other articles.

Chips or turnings of the heartwood of G. officinale (guaiaci lignum) are employed in the preparation of the decoctum sarsae compositum of British pharmacy. They may be recognized by being either yellow or greenish-brown in colour, and by turning bluish-green when treated with nitric acid, or when heated with corrosive sublimate, and green with solution of chloride of lime. They are occasionally adulterated with boxwood shavings. Lignum vitae is imported chiefly from St Domingo, the Bahamas, and Jamrica. The foliage of guaiacum trees is stated by Dr Asa Gray to be employed in the West Indies instead of soap to scour and whiten floors. The bark was formerly used in medicine; it contains much calcium oxalate, and yields on incineration 23 per cent, of ash. Guaiacum resin, the guaiaci resina of pharmacopoeias, is obtained from the wood as an exudation from natural fissures or from incisions; by heating billets about 3 feet in length, bored to permit of the outflow of the resin; or by boiling chip3 and raspings in water to which salt has been added to raise the temperature of ebullition. It occurs in rounded or oval tears, commonly coated with a greyish-green dust, and supposed to be the produce of G. sanctum, or in large brownish or greenish-brown masses, translucent at the edges; fuses at 85° C.; is brittle, and has a vitreous fracture, a specific gravity of U2289 (W. Brande, Phil. Trans., 1806, p. 89), and a slightly balsamic odour, increased by pulverization and by heat; and is at first tasteless when chewed, but produces subsequently a sense of heat in the throat. It is readily soluble in alcohol, ether, chloroform, creasote, oil of cloves, and solutions of caustic alkalies; and its solution gives a blue colour with gluten, raw potato parings, and the roots of horse-radish, carrot, and various other plants. The alcoholic tincture becomes green with sodium hypochlorite, and with nitric acid turns in succession green, blue, and brown. With glycerin it gives a clear solution (B. Squire, Pharm. Joum., May 3, 1879, p. 894), and with nitrous ether a bluish-green gelatinous mass. It is blued by various oxidizing agents, e.g., ozone, and, as Schönbein discovered, by the juice of certain fungi.

To test for blood or haemoglobin, the tincture, which may be prepared from 1 part of the resin to 6 parts of 80 per cent, alcohol (Med. Times, 1873, i. p. 660), is employed according to the method first suggested by Dr John Day, of Geelong, Australia. A drop of the tincture is added to a small quantity of the liquid to be examined, and with this a few drops of ozonic ether (solution of hydrogen peroxide in ether) are then shaken. The ether dissolves the resin, which, acted on by the haemoglobin, becomes of a bright blue colour. Misleading reactions may sometimes result from the use of white bibulous paper, or from the presence of bile, when the test is applied in cases of haematuria (Finlayson, Clinical Manual, p. 391, 1878). Guaiacum resin, according to Hadelich (Erdmann's Jowrn. f. prakt. Chemie, lxxxvii., 1862, pp. 321-343), has the following percentage composition :— gτιaiaconic acid, C 38 H 40 O 10 , a substance giving a transient blue colour with oxidizing agents, 70'35; guaiaretic add, C 20 H 2β O 4 , 10 - 5; guaiac beta-resin, 9’76; gum 3 7; insoluble ash constituents , 79; minute quantities of guaiacic acid, C 12 H lβ O 6 , with guaiac yellow and impurities, 4’9. Acted on by heat it yields the decomposition products guaiacene, C 5 H 8 O, and guaiacol, C 7 H 8 O 2 , and kreasol C 8 H 10 O 2 , the first at 118° C., and the other two at 205°-210° C. (cf. Chemistry, vol. v. p. 564), and, at a still higher temperature, pyroguaiacin, θ38H44θβ∙, ~

Guaiacum wood was first introduced into Europe by the Spaniards in 1508, and Nicolaus Poll, writing in 1517 (see Luisinus, De Morbo Gallico, p. 210, Ven., 1566), states that some three thousand persons in Spain had already been restored to health by it. The virtues of the resin, however, were not known until a later period, and in Thomas PayneΓs translation (Of the Wood called Guaiacum, &c,, p. 9, ed. of 1540) of Ulrich von Hutten’s treatise De Morbi Gallici curatione per administratiinem ligni guaiaci (1519) we read of the wood :—“There foloweth fro it, whan it bourneth a gomme, which we yet knowe not, for what pourpose it serueth.” Fliickiger and Hanbury {Ρharmacographia, p. 95) state that the first edition of the London Pharmacopoeia in which they find the resin mentioned is that of 1677. The decoction of the wood was administered in gout, the stone, palsy, leprosy, dropsy, epilepsy, and other diseases, but principally in the “morbus gallicus,” or syphilis, for which it was reckoned a certain specific, insomuch that at first *' the physitions wolde not allowe it, perceyuynge that theyr profite wolde decay therby” (Paynel, op. cit., p. 8). Minute instructions are given in old works as to the mode of administering guaiacum. The patient was confined in a closed and heated chamber, w⅛s placed on the lowest possible diet, and, after liberal purgation, was made twice a day to drink a milk-warm decoction of the wood. The use of salt was specially to be avoided. A decoction of 1 lb of guaiacum was held to be sufficient for the four first days of the treatment. The earlier opinions as to the efficacy of guaiacum came to be much modified in the course of time, and Dr Pearson (Observations on the Effects of Various Articles of the Mak Med. in the Cure of Lues Venerea, chap, i., 2d ed., 1807) says :—“I never saw one single instance in which the powers of this medicine eradicated the venereal virus.” He found its beneficial effects to be most marked in cases of secondary symptoms. Guaiacum resin is an ingredient in the mistura guaiaci, tinctura guaiaci ammoniata, and pilula hydrargyri subchloridi composita of the British Pharmacopoeia. It is administered in cutaneous diseases, more especially those of a syphilitic character; for long-standing gouty and rheumatic affections, as in the nostrum known as “Chelsea pensioner;” in some forms of neuralgia; in sciatica (Lancet, 1864, i. p. 459); bronchorrhcea; tonsillitis (see inter alia, Lancet, 1864, ii. p. 735); and in sorethroat, or in incipient sore-throat of whatever kind, in the form of the simple resin (Broadbent, Lancet, 1867, i. p. 393); and has been found serviceable in amenorrhoea and ovarian complaints of inflammatory origin (Cleland, Brcιithw. Retrosp., 1873, i. p. 347); and formerly (Graily Hewitt, Dis. of Women, p. 387, 3d ed., 1872) was much employed in dysmenorrhoea. Copland (Med. Dick, ii. 656) regards the decoction or tincture of guaiacum as the best of diaphoretics, especially when the skin is cool as well as .dry. Pearson found that if a patient exposed himself freely to the air, guaiacum acted as a diuretic, instead of as a diaphoretic. Guaiacum causes, when administered, dryness in the mouth, thirst,»and a feeling of warmth in the stomach. According to Pearson, it increases the temperature of the skin and quickens the pulse. It has, seemingly, a considerable influence in lessening excessive secretion from mucous surfaces. In large doses it occasions headache, pyrexia, great heat at the epigastrium, and purging and vomiting. Guaiacum resin is sometimes adulterated with common resin, and has itself been used to sophisticate the resin of scamnιony and of jalap.

See, besides the above-quoted works, Macfadyen, The Flora of Jamaica, p. 187, 1837; J. Lindley, Flora Medica, p. 214, 1838; Asa Gray, Genera of the Plants of the United States, vol. ii. p. 121, pl 148 and 149, 1849; Berg and Schmidt, Offizin. Gewächse, ii. pl. xiv.b, 1863; Grisebach, ^Flora of the Brit. West Ind. Islands, p. 134, 1864; E. J. waring, Manual of Practical Therapeutics, 3d ed., 1871; Bentley and Redwood, Pereira's Flein. of Mat. Med. and Therap., p. 892, 1874; Bentley and Trimen. Medicinal Plants, pt. 30, tab. 41, 1878; and Lanessan, Hist, des Drogues, t pp 194-201, 1878. For lists of numerous early treatises on guaiacum, see Reuss, Repertorium, tom. xi. p. 142,1816. and E. J. waring. Bibliotheca Therapeutica, ii., New. Syd. Soc., 1879.