virtues. Of the latter he gives a long account, noticing also the methods of smoking and chewing the herb prevalent among the Indians. He also supplies a small woodcut representing the plant, which he states to have white flowers, red in the centre.

Jacques Gohory,' who cultivated the plant in Paris at least as early as 1572, describes its flowers as shaded with red, and enumerates various medicinal preparations made from it.

In the Maison Rustique of Charles Estienne, edition of 1583, the author gives a "Discours sur la Nicotiane ou Petum mascle," in which he claims for the plant the first place among medicinal herbs, on account of its singular and almost divine virtues.

The cultivation of tobacco in England, except on a very small scale in a physic garden, has been prohibited by law since 1660.

Description-Amongst the various species of Nicotiana cultivated for the manufacturing of smoking tobacco and snuff, N. Tabacum is by far the most frequent, and is almost the only one named in the pharmacopoeias as medicinal. Its simple stem, bearing at the summit a panicle of tubular pink flowers, and growing to the height of a man, has oblong, lanceolate simple leaves, with the margin entire. The lower leaves, more broadly lanceolate, and about 2 feet long by 6 inches wide, are shortly stalked. The stem-leaves are semi-amplexicaul, and decurrent at the base. Cultivation sometimes produces cordate-ovate forms of leaf, or a margin more or less uneven, or nearly revolute.

All the herbaceous parts of the plant are clothed with long soft hairs, made up of broad, ribbon-like, striated cells, the points of which exude a glutinous liquid. Small sessile glands are situated here and there on the surface of the leaf. The lateral veins proceed from the thick midrib in straight lines, at angles of 40° to 75°, gently curving upwards only near the edge. In drying, the leaves become brittle and as thin as paper, and always acquire a brown colour. Even by the most careful treatment of a single leaf, it is not possible to preserve the green hue.

The smell of the fresh plant is narcotic; its taste bitter and nauseous. The characteristic odour of dried tobacco is developed during the process of curing.

Chemical Composition-The active principle of tobacco, first isolated in 1828 by Posselt and Reimann, is a volatile, highly poisonous alkaloid termed Nicotine, CH4N2. It is easily extracted from tobacco by means of alcohol or water, as a malate, from which the alkaloid can be separated by shaking it with caustic lye and ether. The ether is then expelled by warming the liquid, which finally has to be mixed with slaked lime and distilled in a stream of hydrogen, when the nicotine begins to come over at about 200° C.

Nicotine is a colourless oily liquid, of sp. gr. 1027 at 15° C., deviating the plane of polarization to the left; it boils at 247° and

1 Instruction sur l'herbe Petum ditte en France l'herbe de la Royne ou Médicée. Paris, 1572.

212 Car. 11. c. 34; 15 Car. II. c. 7.For further information on the history of tobacco, see Tiedemann, Geschichte des

Tabaks, Frankfurt, 1854.-We have not consulted Fairholt, Tobacco, its History, Lond. 1859.

3 Microscopic structure of tobacco leaves. See Pocklington, Pharm. Journal, v. (1874) 301.

does not concrete even at 10° C. It has a strongly alkaline reaction, an unpleasant odour, and a burning taste. It quickly assumes a brown colour on exposure to air and light; and appears even to undergo an alteration by repeated distillation in an atmosphere deprived of oxygen. Nicotine dissolves in water, but separates on addition of caustic potash; it occurs in the dried leaves to the extent of about 6 per cent., but is subject to great variation. The seeds of tobacco are stated by Kosutany1 as grown in Hungary to contain from 0.28 to 0.67 per cent. of the alkaloid.

It has not been met with in tobacco-smoke by Vohl and Eulenberg (1871), though other chemists assert its occurrence. The vapours were found by the former to contain numerous basic substances of the picolinic series, and ceded to caustic potash, hydrocyanic acid, sulphuretted hydrogen, several volatile fatty acids, phenol and creasote. There was further observed in the imperfect combustion of tobacco the formation of laminæ fusible at 94° C., and having a composition C1oH1. Oxide of carbon is also largely met with.

Tobacco leaves, whether fresh or dried, yield when distilled with water a turbid distillate in which, as observed by Hermbstädt in 1823, there are formed, after some days, crystals of Nicotianin or Tobacco Camphor. According to J. A. Barral, nicotianin contains 7·12 per cent. of nitrogen (?). By submitting 4 kilogrammes of good tobacco of the previous year to distillation with much water, we obtained nicotianin, floating on the surface of the distillate, in the form of minute acicular crystals, which we found to be devoid of action on polarized light. The crystals have no peculiar taste, at least in the small quantity we tried; they have a tobacco-like smell, perhaps simply due to the water adhering to them. When an attempt was made to separate them by a filter, they entirely disappeared, being probably dissolved by an accompanying trace of essential oil. The clear water showed an alkaline reaction partly due to nicotine; this was proved by adding a solution of tannic acid, which caused a well-marked turbidity. Nicotianine is in our opinion a fatty acid contaminated with a little volatile oil as in the case of Capsicum (see page 454), or Iris (see article Rhizome Iridis).

Among the ordinary constituents of leaves, tobacco contains albumin, resin and gum. In smoking, these substances, as well as the cellulose of the thick midrib, would yield products not agreeable to the consumer. The manufacturer therefore discards the midrib, and endeavours by further preparation to ensure at least the partial destruction of these unwelcome constituents, as well as the formation of certain products of fermentation (ferment-oils), which may perhaps contribute to the aroma of tobacco, especially when saccharine substances, liquorice, or alcohol, are added in the maceration to which tobacco is subjected.

Tobacco leaves are remarkably rich in inorganic constituents, the proportion varying from 16 to 27 per cent. According to Boussingault, they contain when dry about 1 per cent. of phosphoric acid, and from 3 to 5 per cent. of potash, together with 2 to 4 per cent. of nitrogen partly in the form of nitrate, so that to enable the tobacco plant to flourish, it must have a rich soil or continual manuring.3

1 Dragendorff's Jahresbericht, 1874. 98. 2 Poggiale and Marty (1870) stated hydrocyanic acid to be absent.

3 For further particulars on the chemistry of tobacco cultivation see Boussingault, Ann. de Chim. et de Phys. ix. (1866) 50.

The lime, amounting to between a quarter and a half of the entire quantity of ash, is in the leaf combined with organic acids, especially malic, perhaps also citric. The proportion of potash varies greatly, but may amount to about 30 per cent. of the ash.

Commerce-There were imported into the United Kingdom in the year 1872, 45,549,700 lb. of unmanufactured tobacco, rather more than half of which was derived from the United States of America. The total value of the commodity thus imported was £1,563,382; and the duty levied upon the quantity retained for home consumption amounted to £6,694,037. In 1876 the consumption of tobacco had increased to 47,000,000 lb., i. e. 1 lb. per head of the population.

In the United States 559,049 acres of land being in 1875 under cultivation with tobacco yielded a crop of 367,000,000 lb.

Uses Tobacco has some reputation in the removal of alvine obstructions, but it is a medicine of great potency and is very rarely used.

Substitutes Of the other species of Nicotiana cultivated as Tobacco, N. rustica L. is probably the most extensively grown. It is easily distinguished by its greenish yellow flowers, and its stalked ovate leaves. In spite of their coarser texture, the leaves dry more easily than those of N. Tabacum, and with some care may even be made to retain their green colour. N. rustica furnishes East Indian Tobacco, also the kinds known as Latakia and Turkish Tobacco.

N. persica Lindl. yields the tobacco of Shiraz. N. quadrivalvis Pursh, N. multivalvis Lindl. and N. repanda Willd. are also cultivated plants, the last named, a plant of Havana, being used in the manufacture of a much valued kind of cigar.

SCROPHULARIACEÆ.

FOLIA DIGITALIS.

Foxglove Leaves; F. Feuilles de Digitale; G. Fingerhutblätter. Botanical Origin-Digitalis purpurea L., an elegant and stately plant, common throughout the greater part of Europe, but preferring siliceous soils and generally absent from limestone districts. It is found on the edges of woods and thickets, on bushy ground and commons, becoming a mountain plant in the warm parts of Europe. It occurs in the island of Madeira, in Portugal, Central and Southern Spain, Northern Italy, France, Germany, the British Isles and Southern Sweden, and in Norway as far as 63° N. lat.; it is however very unequally distributed, and is altogether wanting in the Swiss Alps and the Jura.1 As a garden plant it is well known.

History The Welsh "Physicians of Myddvai" appear to have frequently made use of foxglove for the preparation of external medicines. Fuchs and Tragus figured the plant; the former gave it the

3

4

name of Digitalis, remarking that up to the time at which he wrote, there was none for the plant in either Greek or Latin. At that period it was regarded as a violent medicine. Parkinson recommended it in 1640 in the "Theatrum botanicum," and it had a place in the London Pharmacopoeia of 1650 and in several subsequent editions. The investigation of its therapeutic powers (1776-9) and its introduction into modern practice are chiefly due to Withering, a well-known English botanist and physician.'

The word fox-glove is said to be derived from the Anglo-Saxon Foxes-glew, i.e. fox-music, in allusion to an ancient musical instrument consisting of bells hung on an arched support. In the Scandinavian idioms the plant bears likewise the name of foxes bell.

Description-Foxglove is a biennial or perennial, the leaves of which ought to be taken from the plant while in full flower. The lower leaves are ovate with the lamina running down into a long stalk; those of the stem become gradually narrower, passing into ovatelanceolate with a short broadly-winged stalk, or are sessile. All have the margin crenate, crenate-dentate, or sub-serrate, are more or less softly pubescent or nearly glabrous on the upper side, much paler and densely pubescent on the under, which is marked with a prominent network of veins. The principal veins diverge at a very acute angle from the midrib, which is thick and fleshy. The lower leaves are often a foot or more long, by 5 to 6 inches broad; those of the stem are smaller.

When magnified, the tip of each crenature or serrature of the leaf is seen to be provided with a small, shining, wart-like gland. The hairs of the lower surface are simple, and composed of jointed cells which flatten in drying; those of the upper surface are shorter.

In preparing foxglove for medicinal use, it is the custom of some druggists to remove the whole of the petiole and the thicker part of the midrib, retaining only the thin lamina, which is dried with a gentle heat. The fresh leaf has when bruised an unpleasant herbaceous smell, which in drying becomes agreeable and tea-like. The dried leaf has a very bitter taste.

Chemical Composition-Since the beginning of the present century, numerous attempts have been made to prepare the active principle of foxglove, and the name Digitalin has been successively bestowed on widely different substances.

Among the investigators engaged in these researches, we may point out Walz (1846-1858), Kosmann (1845-46, 1860), Homolle partly with Quévenne (1845-61), Nativelle (1872), and especially Schmiedeberg (1874). The latter has prepared a new, well-defined, crystallizable principle, Digitoxin, from Digitalis. He exhausted with water the leaves previously dried and powdered, and then extracted them repeatedly with dilute alcohol, 50 per cent.; the

1 Withering (William), Account of the Fox-glove, Birmingham, 1785. 8°.

2 Prior, Popular Names of British Plants, ed. 2. 1870. 84.

3 This method of preparing the leaf was directed in the London Pharmacopoeia of 1851, but it had long been in use. Νο

particular directions are given in the British Pharmacopoeia.

For further particulars on Schmiedeberg's very elaborate researches, the reader may consult my abstract of them in Pharm. Journ. v. (1875) 741.-F.A. F.

tincture thus obtained was then mixed with basic acetate of lead as long as it produced a precipitate. The latter being separated, the filtered liquid was concentrated and the deposit now formed, after some days, removed from the aqueous liquid. It was then washed with a dilute solution of carbonate of sodium, by which a yellow matter (chrysophan?) was partly removed. The substance was then dried, and yielded to chloroform a brownish mass, which after the chloroform had been driven off, was purified by benzin. This liquid dissolved the remainder of the yellow or orange matter, and a little fat, leaving crude digitoxin, which is to be purified by recrystallization from warm alcohol, 80 per cent., adding a little charcoal. This purification still yields yellowish crystals, which ought to be washed again with carbonate of sodium, ether or benzin, and then recrystallized from warm absolute alcohol, containing a little chloroform. This process, however, will only afford colourless crystals provided it be so performed as to cause the separation of digitoxin on account of the cooling of the solution, not by the evaporation of the solvent. If the liquid is instead allowed to evaporate it will soon assume a darker coloration. the way just pointed out, perfectly colourless scales or needleshaped crystals of pure digitoxin are at length formed, the yield being not more considerable than about one part from 10,000 of dried leaves.

In

Digitoxin is insoluble in water, to which it does not even impart its intensely bitter taste as displayed in the alcoholic solution. It is likewise insoluble in benzin or bisulphide of carbon, very sparingly soluble in ether, more abundantly so in chloroform, the latter liquid however acting but very slowly on digitoxin. Its best solvent is alcohol, either cold or warm. The composition of digitoxin answers to the formula, CH3307.

Digitoxin warmed with concentrated hydrochloric acid assumes a yellow or greenish hue, the same which is commonly attributed to commercial" digitalin." Digitoxin is not a saccharogenous matter; in alcoholic solution it is decomposed by dilute acids, and then affords Toxiresin, an uncrystallizable, yellowish substance, which may easily be separated on account of its ready solubility in ether; it appears to be produced also if digitoxin is maintained for some time in the state of fusion at about 240° C. Toxiresin proved to be a very powerful poison, acting energetically on the heart and muscles of frogs. The very specific action of foxglove is due-not exclusively-to digitoxin; it is so highly poisonous that Schmiedeberg thinks it not at all fit for medicinal use, which might rather be confined to other constituents of foxglove, as, for instance, to those obtained from the seeds under the names of digitalin and digitaléin. The latter, however, are of more difficult extraction than digitoxin.

The preparation of digitoxin is similar to that of Nativelle's crystallized "digitalin;" the former as well as paradigitogenin' are largely found in Nativelle's digitalin.

The Digitalin of Nativelle-The researches on digitalis of this chemist, for which the Orfila prize of 6000 francs was awarded in 1872, have resulted in the extraction of a crystallized preparation

1 A derivative of digitoxin as extracted by Schmiedeberg from the seeds of foxglove,