it is without acid reaction but decomposes alkaline carbonates, forming uncrystallizable salts easily soluble in water or alcohol. It is insoluble in water, benzol, or bisulphide of carbon, but dissolves in ether, chloroform, acetic acid or alcohol. With oxidizing agents it acquires a

transient blue tint.

Guaiaretic Acid, C20 H264, discovered by Hlasiwetz in 1859, may be extracted from the crude resin by alcoholic potash or by quick lime. With the former it produces a crystalline salt; with the latter an amorphous compound: from either, the liquid which contains chiefly a salt of guaiaconic acid, may be easily decanted. Guaiaretic acid is obtained by decomposing one of the salts referred to with hydrochloric acid, and crystallizing from alcohol. The crystals, which are soluble also in ether, benzol, chloroform, carbon bisulphide or acetic acid, but neither in ammonia nor in water, melt below 80° C. and may be volatilized without decomposition. The acid is not coloured blue by oxidizing agents.

After the extraction of the guaiaconic acid there remains a substance insoluble in ether to which the name Guaiac Beta-resin has been applied. It dissolves in alcohol, acetic acid or alkalis, and is precipitated by ether, benzol, chloroform or carbon bisulphide in brown flocks, the composition of which appears not greatly to differ from that of guaiaconic acid.

Guaiacic Acid, C12H1606, obtained in 1841 by Thierry from guaiacum wood or from the resin, crystallizes in colourless needles. Hadelich was not able to obtain more than one part from 20,000 of guaiacum resin. Hadelich's Guaiac-yellow, the colouring matter of guaiacum resin, first observed by Pelletier, crystallizes in pale yellow quadratic octohedra, having a bitter taste. Like the other constituents of the resin, it

is not a glucoside.

The decomposition-products of guaiacum are of peculiar interest. On subjecting the resin to dry distillation in an iron retort and rectifying the distillate, Guaiacene (Guajol of Völckel), CHO, passes over at 118° C. as a colourless neutral liquid having a burning aromatic taste.

At 205°-210° C., there pass over other products, Guaiacol (or Pyroguaiacic Acid or Guaiacyl-hydride), C'H8O2, and Kreosol, C8H1002. Both are thickish, aromatic, colourless liquids, which become green by caustic alkalis, blue by alkaline earths, and are similar in their chemical relations to eugenic acid. Guaiacol has been prepared synthetically by GorupBesanez (1868) by combining iodide of methyl, CH3I, with pyrocatechin, C6H6O2.

The

After the removal by distillation of the liquids just described, there sublime upon the further application of heat, pearly crystals of Pyroguaiacin, C38H4406, an inodorous substance melting at 180° C. same compound is obtained together with guaiacol by the dry distillation of guaiaretic acid. Pyroguaiacin is coloured green by ferric chloride, and blue by warın sulphuric acid. The similar reactions of the crude resin are probably due to this substance (Hlasiwetz).

Beautiful coloured reactions are likewise exhibited by two new acids which Hlasiwetz and Barth obtained (1864) in small quantity together with traces of fatty volatile acids, by melting purified resin of guaiacum with potassium hydrate. One of them is isomeric with pyrocatechuic

acid.

Uses-Guaiacum resin is reputed diaphoretic and alterative. It is frequently prescribed in cases of gout and rheumatism.

Adulteration-The drug is sometimes imported in a very foul condition and largely contaminated with impurities arising from a careless method of collection.

RUTACEE.

CORTEX ANGOSTURA.

Cortex Cuspariæ; Angostura Bark, Cusparia Bark, Carony Bark; F. Ecorce d'Angusture; G. Angostura-Rinde.

Botanical Origin-Galipea Cusparia St. Hilaire (G. officinalis Hancock, Bonplandia trifoliata Willd.), a small tree, 12 to 15 feet high, with a trunk 3 to 5 inches in diameter, growing in abundance on the mountains of San Joaquin de Caroni in Venezuela, between 7° and 8° N. lat. According to Hancock,1 who was well acquainted with the tree, it is also found in the Missions of Tumeremo, Uri, Alta Gracia, and Cupapui, districts lying eastward of the Caroni and near its junction with the Orinoko. The bark is brought into commerce by way of Trinidad.

History-Angostura Bark is said to have been used in Madrid by Mutis as early as 17592 (the year before he left Spain for South America), but it was certainly unknown to the rest of Europe until much later. Its real introducer was Brande, apothecary to Queen Charlotte, and father of the distinguished chemist of the same name, who drew attention to some parcels of the bark imported into England in 1788.3 In the same year a quantity was sent to a London drug firm by Dr. Ewer of Trinidad who describes it as brought to that island from Angostura by the Spaniards. The drug continued to arrive in Europe either by way of Spain or England, and its use was gradually diffused. In South America it is known as Quina de Caroni and Cascarilla del Angostura.

Description-The bark occurs in flattish or channelled pieces, or in quills rarely as much as 6 inches in length and mostly shorter. The flatter pieces are an inch or more in width and of an inch in thickness. The outer side of the bark is coated with a yellowish-grey corky layer, often soft enough to be removeable with the nail, and then displaying a dark brown, resinous under surface. The inner side is light brown with a rough, slightly exfoliating surface indicating close adhesion to the wood, strips of which are occasionally found attached to it the obliquely cut edge also shows that it is not very easily detached. The bark has a short, resinous fracture and displays on its transverse edge sharply defined white points, due to deposits of oxalate of calcium. It has a bitter taste and a nauseous musty odour.

Microscopic Structure-The most striking peculiarity is the great

1 Observations on the Orayuri or Angustura Bark Tree, Trans. of Medico-Botanical Society, 1827-29.-Hancock endeavoured to prove his tree distinct from G. Cusparia St. Hil., but Farre and Don who subsequently examined his specimens decided that the two were the same. With the assistance of Prof. Oliver, I also have examined (1871)

Hancock's plant, comparing it with his figure and other specimens, and have arrived at the conclusion that it is untenable as a distinct species.-D. H.

2 Martiny, Encyklopädie, i. (1843) 242. 3 Brande, Experiments and Observations on the Angustura Bark. 1791. 2nd ed. 1793. 4 London Med. Journ x. (1789) 154.

H

number of oil-cells scattered through the tissue of the bark. They are not much larger than the neighbouring parenchymatous cells and are loaded with yellowish essential oil or small granules of resin. Numerous other cells contain bundles of needle-shaped crystals of oxalate of calcium or small starch granules. The liber exhibits bundles of yellow fibres, to which the foliaceous fracture of the inner bark is due.

Chemical Composition-Angostura bark owes its peculiar odour to an essential oil which it was found by Herzog1 to yield to the extent of per cent. According to this chemist it has the composition C13H24O; it is probably a mixture of a hydrocarbon (C10H8) with an oxygenated oil. Its boiling point is 266° C.

The bitter taste of the bark is attributed to a substance pointed out in 1833 by Saladin and named Cusparin. It is said to be crystalline, neutral, melting at 45° C., soluble in alcohol, sparingly in water, precipitable by tannic acid. The bark is stated to yield it to the extent of 1.3 per cent. Herzog endeavoured to prepare it but without success. A cold aqueous infusion of angostura bark yields an abundant redbrown precipitate with ferric chloride. Thin slices of the bark are not coloured by solution of ferrous sulphate, so that tannin appears to be

absent.

Uses-Angostura bark is a valuable tonic in dyspepsia, dysentery and chronic diarrhoea, but is falling into disuse.

Adulteration-About the year 1804, a quantity of a bark which proved to be that of Strychnos Nur Vomica reached Europe from India, and was mistaken for Cusparia. The error occasioned great alarm and some accidents, and the use of angostura was in some countries even prohibited. The means of distinguishing the two barks (which are not likely to be again confounded) are amply contained in the above-given descriptions and tests.

FOLIA BUCHU.

Folia Bucco; Buchu, Bucchu, Bucha or Buka Leaves; F. Feuilles de Bucco; G. Bukublätter.

Botanical Origin-The Buchu leaves of medicine are afforded by three species of Barosma.2 The latter are erect shrubs some feet in height with glabrous rod-like branches, opposite leaves furnished with conspicuous oil-cells on the toothed margin as well as generally on the under surface. The younger twigs and several parts of the flower are also provided with oil-cells. The white flowers with 5-partite calyx, and the fruit formed of five erect carpels, are often found, together with small leafy twigs, in the drug of commerce.

The leaves of the three species referred to may be thus distinguished:

1. Barosma crenulata Hook. (B. crenata Kunze).-Oblong, oval, or obovate, obtuse, narrowed towards the base into a distinct petiole; margin serrulate or crenulate; dimensions, to 1 inches long, to of an inch wide.

1 Archiv d. Pharm. xciii. (1858) 146.

2 From Sapùs, heavy, and doμm), odour.

2. B. serratifolia Willd.-Linear-lanceolate, equally narrowed towards either end, three-nerved, apex truncate always furnished with an oil-cell; margin sharply serrulate; 1-1 inches long by about of an inch wide.

3. B. betulina Bartling.-Cuneate-obovate, apex recurved; margin sharply denticulate, teeth spreading; to of an inch long by to 1% wide. Substance of the leaf more harsh and rigid than in the preceding.

B. crenulata and B. betulina grow in the Divisions of Clanwilliam and Worcester, north and north-east of Cape Town, and the former even on Table Mountain close to the capital; B. serratifolia is found in the Division of Swellendam further south.

History The use of Buchu leaves was learnt from the Hottentots by the colonists of the Cape of Good Hope. The first importations of the drug were consigned to the house of Reece & Co. of London, who introduced it to the medical profession in 1821.1 The species appears to have been B. crenulata.

Description-In addition to the characters already pointed out, we may observe that buchu leaves of either of the kinds mentioned are smooth and glabrous, of a dull yellowish-green hue, somewhat paler on the under side, on which oil-cells in considerable number are perceptible.

The leaves of B. crenulata vary in shape and size in different parcels, in some the leaves being larger and more elongated than in others, probably according to the luxuriance of the bushes in particular localities. Those of B. serratifolia and B. betulina present but little variation. Each kind is always imported by itself. Those of B. betulina are the least esteemed and fetch a lower price than the others, yet appear to be quite as rich in essential oil.

Buchu leaves have a penetrating peculiar odour and a strongly

aromatic taste.

Microscopic Structure-The essential oil is contained in large. cells close beneath the epidermis of the under side of the leaf. The oilcells are circular and surrounded by a thin layer of smaller cells; they consequently partake of the character of the oil-ducts in the aromatic roots of Umbellifera and Composite. The latter however are elongated.

The upper side of the leaf of Barosma exhibits an extremely interesting peculiarity. There is a colourless layer of cells separating the epidermis from the green inner tissue (mesophyllum). If the leaves are examined under alcohol or almond-oil the colourless layer is seen to be very narrow, and the thin walls of its cells shrunken and not clearly distinguishable. If the transverse sections are examined under water, these cells immediately swell up and become strongly distended, giving off an abundance of mucilage, the latter being afforded by the solution of the very cell-walls. The mucilage of buchu leaves thus originates in the same way as in flax seed or quince seed, but in the former the epidermis is thrown off without alteration. We are not aware that other mucilaginous leaves possess a similar structure, at least not those of Althaea officinalis and of Sesamum which we examined.

Chemical Composition-The leaves of B. betulina afforded us by

1 R. Reece, Monthly Gazette of Health for Feb. 1821. 799.

2 Flückiger in Schweiz. Wochenschrift für Pharm. Dec. 1873, with plate.

distillation 1.56 per cent. of volatile oil, which has the odour rather of peppermint than of buchu and deviates the ray of polarized light considerably to the left. On exposure to cold it furnishes a camphor which after re-solution in spirit of wine, crystallizes in needle-shaped forms. After repeated purification in this manner, the crystals of Barosma Camphor have an almost pure peppermint odour; they fuse at 85° C. and begin to sublime at 110° C. After fusion they again solidify only at 50° C. Submitted to elementary analysis, the crystals yielded us 74.08 per cent. of carbon and from 9 to 10 per cent. of hydrogen. Barosma camphor is abundantly soluble in bisulphide of carbon.

2

The crude oil from which the camphor has been separated has a boiling point of about 200° C., quickly rising to 210° or even higher. That which distilled between these temperatures was treated with sodium, rectified in a current of common coal gas and submitted to elementary analysis, afforded us 77.86 per cent. of carbon and 10.58 of hydrogen. The formula C10H16O would require 78.94 of carbon and 10.53 of hydrogen.

On addition of perchloride of iron an aqueous infusion of buchu leaves assumes a dingy brownish green colour changing to red by an alkali. The infusion added to a concentrated solution of acetate of copper causes a yellow precipitate which dissolves in caustic potash, affording a green solution. This may be due to the presence of a substance of the quercitrin or rutin class.

3

When the leaves are infused in warm water, the mucilage noticed under the microscope may easily be pressed out. It requires for precipitation a large amount of alcohol, being readily miscible with dilute alcohol. Neutral acetate of lead produces a yellow precipitate in an infusion of the leaves; the liquid affords a precipitate by a subsequent addition of basic acetate of lead. The latter precipitate is (probably) due to the mucilage, that afforded by neutral acetate partly to mucilage and partly, we suppose, to rutin or an allied substance. Yet the mucilage of buchu leaves is of the class which is not properly dissolved by water, but only swells up like tragacanth.

The leaves of B. crenulata afford upon incineration 47 per cent. of ash.

The Diosmin of Landerer is entirely unknown to us.

Commerce-The export of Buchu from the Cape Colony in 1872 was 379,125 lb., about one-sixth of which quantity was shipped direct to the United States.5

Uses-Buchu is principally administered in disorders of the urinogenital organs. It is reputed diuretic and diaphoretic. In the Cape Colony the leaves are much employed as a popular stimulant and stomachic, infused in water, sherry or brandy. They are also extensively used in the United States, both in regular medicine and by the vendors of secret remedies.

1 Messrs. Allen and Hanburys operating on larger quantities obtained 1.63 per cent.

Our supply of the substance having been exhausted by two analyses we cannot regard the above figures as sufficient for the calculation of a formula.

3 It seems green as long as it is in the blue cupric liquid.

Ginelin's Chemistry, xviii. 194.

5 Blue Book published at Cape Town, 1873.