part 32

(1878).

[447] Fig. by Engler in _Flora Brasil_. fasc. 65 (1874) tab. 30. _Pilocarpus pauciflorus_ St. Hilaire (_Flora Brasiliæ meridionalis_, i. 1824. tab. 17) appears also to be very similar.

[448] Lib. iv. cap. 57, 59, and v. cap. 19, p. 310, of the work quoted in the appendix.

[449] _Description des Plantes de l’Amérique_, 1693. 58. Pl. lxxv. and lxxvi.

[450] Stiles, _Pharm. J._ vii. (1877) 629; also Lanessan’s French translation of the _Pharmacographia_, i. (1878) 253.

The occurrence of another peculiar alkaloid in Pilocarpus has been asserted, but not ultimately proved.

The leaves contain about ½ per cent. of essential oil, the prevailing constituent of it being a dextrogyrate terpene, C₁₀H₁₆, boiling at 178°, which forms a crystallized compound C₁₀H₁₆ + 2HCl melting at 49°·5 C.

=Uses=—Pilocarpine being a powerful diaphoretic and sialagogue, the leaves of Jaborandi are used to some extent in pharmaceutical preparations.

=Other Kinds of Jaborandi=—This name, as above stated, has originally been given to plants of the order Piperaceæ, some of which are still known in Brazil under the name Jaborandi. The following may be quoted as being used at least in that country: _Serronia Jaborandi_[451] Gaudichaud, _Piper reticulatum_ L. (_Enckea_ Miquel), _Piper citrifolium_ Lamarck (_Steffensia_ Kunth), _Piper nodulosum_ Link, _Artanthe mollicoma_ Miq.

_Aubletia trifolia_[452] Richard (_Monniera_ L.) and _Xanthoxylum elegans_ Engler, belonging to the same order as Pilocarpus itself, are also sometimes called Jaborandi.

We are not aware that other leaves than those of Pilocarpus are imported to some extent in Europe under the name of Jaborandi.

AURANTIACEÆ.

FRUCTUS LIMONIS.

_Lemon_; F. _Citron_, _Limon_; G. _Citrone_, _Limone_.

=Botanical Origin=—_Citrus Limonum_ Risso (_C. Medica_ var. β Linn.), a small tree 10 to 15 feet in height, planted here and there in gardens in many subtropical countries, but cultivated as an object of industry on the Mediterranean coast between Nice and Genoa, in Calabria, Sicily, Spain, and Portugal.

The tree which is supposed to represent the wild state of the lemon and lime, and as it seems to us after the examination of numerous specimens in the herbarium of Kew, of the citron (_Citrus Medica_ Risso) also, is a native of the forests of Northern India, where it occurs in the valleys of Kumaon and Sikkim.

The cultivated lemon-tree is of rather irregular growth, with foliage somewhat pallid, sparse, and uneven, not forming the fine, close head of deep green that is so striking in the orange tree. The young shoots are of a dull purple; the flowers, which are produced all the year except during the winter, and are in part hermaphrodite and in part unisexual, have the corolla externally purplish; internally white, and a delicate aroma distinct from that of orange blossom. The fruit is pale yellow, ovoid, usually crowned by a nipple.

[451] Already known to Piso.

[452] The original Jaborandi of Piso, according to Peckolt. Dragendorff’s _Jahresbericht_, 1875. 163.

=History=—The name of the lemon in Sanskrit is _Nimbuka_; in Hindustani, _Limbu_, _Limu_, or _Ninbu_. It is probably originally a Cashmere word, which was transferred to the Sanskrit in comparatively modern times, not in the antiquity.[453] From these sounds the Arabians formed the word _Limun_, which has passed into the languages of Europe.

The lemon was unknown to the inhabitants of ancient Greece and Rome; but it is mentioned in the Book of Nabathæan Agriculture,[454] which is supposed to date from the 3rd or 4th century of our era. The introduction of the tree to Europe is due to the Arabians, yet at what precise period is somewhat doubtful. _Arance_ and _Limone_ are mentioned by an Arabic poet living in the 11th century, in Sicily, quoted by Falcando.[455] The geographer Edrisi,[456] who resided at the court of Roger II., king of Sicily, in the middle of the 12th century, mentions the lemon (_limouna_) as a very sour fruit of the size of an apple which was one of the productions of Mansouria on the Mahrân or Indus; and he speaks of it in a manner that leads one to infer it was not then known in Europe. This is the more probable from the fact that there is no mention either of lemon or orange in a letter written A.D. 1239 concerning the cultivation of the lands of the Emperor Frederick II. at Palermo,[457] a locality in which these fruits are now produced in large quantity.

On the other hand the lemon is noticed at great length by Ibn Baytar of Malaga, who flourished in the first half of the 13th century, but of its cultivation in Spain at that period there is no actual mention.[458] In 1369 at least citron trees, “arbores citronorum,” were planted in Genoa,[459] and there is evidence that also the lemon-tree was grown on the Riviera di Ponente about the middle of the 15th century, since _Limones_ and also _Citri_ are mentioned in the manuscript _Livre d’Administration_ of the city of Savona, under date 1486.[460] The lemon was cultivated as early as 1494 in the Azores, whence the fruit used to be largely shipped to England; but since the year 1838 the exportation has totally ceased.[461]

=Description=—The fruit of _Citrus Limonum_ as found in the shops[462] is from about 2 to 4 inches in length, egg-shaped with a nipple more or less prominent at the apex; its surface, of a pale yellow, is even or rugged, covered with a polished epidermis. The parenchyme within the latter abounds in large cells filled with fragrant essential oil. The roughness of the surface of the rind is due to the oil-cells. The peel, which varies considerably in thickness but is never so thick as that of the citron, is internally white and fibrous, and is adherent to the pale yellow pulp. The latter is divided into 10 or 12 segments each containing 2 or 3 seeds. It abounds in a pale yellow acid juice having a pleasant sour taste and a slight peculiar odour quite distinct from that of the peel. When removed from the pulp by pressure, the juice appears as a rather turbid yellowish fluid having a sp. gr. which varies from 1·040 to 1·045, and containing in each fluid ounce from 40 to 46 grains of citric acid, or about 9½ per cent.[463] In Italy all the fine and perfect fruit is exported; the windfalls and the damaged fruit are used for the production of the essential oil and the juice. About 13,000 lemons of this kind yield one pipe (108 gallons) of raw juice. Sicilian juice in November will contain about 9 ounces of citric acid per gallon, but 6 ounces when afforded by the fruit collected in April. The juice is boiled down in copper vessels, over an open fire, till its specific gravity is about 1·239.[464] Lemon juice (_Succus limonis_) for administration as a medicine should be pressed as wanted from the recent fruit whenever the latter is obtainable.

[453] Dr. Rice in _New Remedies_, 1878, 263; also private information.

[454] Meyer, _Geschichte der Botanik_, iii. (1856) 68.

[455] Amari, _Storia dei Musulmani di Sicilia_, ii. (1858) 444.

[456] _Géographie d’Edrisi_, traduite par Jaubert, i. (1836) 162.

[457] Huillard-Bréholles, _Historia diplomatica Friderici secundi_, Paris, v. (1857) 571.

[458] _Heil-und Nahrungsmittel von Ebn Baithar_, übersetzt von Sontheimer, ii. (1842) 452.

[459] Belgrano, _Vita privata dei Genovesi_, Genova (1875) 158.

[460] Gallesio, _Traité du Citrus_ (1811) 89, 103.

[461] Consul Smallwood, in _Consular Reports_, Aug. 1873. 986.

[462] There are many kinds of lemon as well as of orange which are never seen in commerce. Risso and Poiteau enumerate 25 varieties of the former and 30 of the latter. See also Alfonso, _Coltivazione degli Agrumi_, Palermo, 2nd edition, 1875.

[463] Stoddart, in _Pharm. Journ._ x. (1869) 203.

[464] R. Warington, _Pharm. Journ_. v. (1875) 385.

The peel (_Cortex limonis_) cut in somewhat thin ribbons from the fresh fruit is used in pharmacy, and is far preferable to that sold in a dried state.

=Microscopic Structure of the Peel.=—The epidermis exhibits numerous stomata; the parenchyme of the pericarp encloses large oil-cells, surrounded by small tabular cells. The inner spongy tissue is built up of very remarkable branched cells, separated by large intercellular spaces. A solution of iodine in iodide of potassium imparts to the cell-walls a transient blue coloration. The outer layers of the parenchymatous tissue contain numerous yellowish lumps of a substance which assumes a brownish hue by iodine, and yields a yellow solution if potash be added. Alkaline tartrate of copper is reduced by this substance, which probably consists of hesperidin. There also occur large crystals of oxalate of calcium, belonging to the monoclinic system. The interior tissue is irregularly traversed by small vascular bundles.

=Chemical Composition=—The peel of the lemon abounds in essential oil, which is a distinct article of commerce, and will be described hereafter.

Lemons, as well as other fruits of the genus _Citrus_, contain a bitter principle, _Hesperidin_, of which E. Hoffmann[465] obtained 5 to 8 per cent. from unripe bitter oranges. He extracted them with dilute alcohol, after they had previously been exhausted by cold water. The alcohol should contain about 1 per cent. of caustic potash; the liquid on cooling is acidulated with hydrochloric acid, when it yields a yellowish crystalline deposit of hesperidin, which may be obtained colourless and tasteless by recrystallization from boiling alcohol. By dilute sulphuric acid (1 per cent.) hesperidin is broken up as follows:—

C₂₂H₂₆O₁₂ = C₁₆H₁₄O₆ + C₆H₁₂O₆. Hesperidin. Hesperetin. Glucose.

Hesperidin is very little soluble even in boiling water or in ether, but dissolves readily in hot acetic acid, also in alkaline solutions, the latter then turning soon yellow and reddish. Pure hesperidin, as presented to one of us by Hoffmann, darkens when it is shaken with alcoholic perchloride of iron, and turns dingy blackish brown when gently warmed with the latter.

[465] _Berichte der Deutschen Chemischen Gesellschaft_ (1876) 26, 685, 693.

_Hesperetin_ forms crystals melting at 223° C., soluble both in alcohol or ether, not in water; they taste sweet. They are split up by potash in Phloroglucin and _Hesperetic acid_, C₁₀H₁₀O₄.

On addition of ferric chloride, thin slices of the peel are darkened, owing probably to some derivative of hesperidin, or to hesperidin itself.

The name hesperidin had also been applied to _yellow_ crystals extracted from the shaddock, _Citrus decumana_ L., the dried flowers of which afford about 2 per cent. of that substance. It is, as shown in 1879 by E. Hoffmann, quite different from hesperidin as described above; he calls it _Naringin_ and assigns to it the formula C₂₃H₂₆O₁₂+4OH₂. Naringin is readily soluble in hot water or in alcohol, not in ether or chloroform. Its solutions turn brown-red on addition of ferric chloride.

Lemon juice, some of the characters of which have been already noticed, is an important article in a dietetic point of view, being largely consumed on shipboard for the prevention of scurvy. In addition to citric acid it contains 3 to 4 per cent. of gum and sugar, and 2·28 per cent. of inorganic salts, of which according to Stoddart only a minute proportion is potash. Cossa[466] on the other hand, who has recently studied the products of the lemon tree with much care, has found that the ash of dried lemon juice contains 54 per cent. of potash, besides 15 per cent. of phosphoric acid.

Stoddart has pointed out the remarkable tendency of citric acid to undergo decomposition,[467] and has proved that in lemons kept from February to July this acid generally decreases in quantity, at first slowly, but afterwards rapidly, until at the end of the period it entirely ceases to exist, having been all split up into glucose and carbonic acid. At the same time the sp. gr. of the juice was found to have undergone but slight diminution:—thus it was 1·044 in February, 1·041 in May, and 1·027 in July, and the fruit had hardly altered in appearance. Lemon juice may with some precautions be kept unimpaired for months or even years. Yet it is capable of undergoing fermentation by reason of the sugar, gum, and albuminoid matters which it contains.

=Commerce=—Lemons are chiefly imported from Sicily, to a smaller extent from the Riviera of Genoa and from Spain. From the published statistics of trade, in which lemons are classed together with oranges under one head, it appears that these fruits are being imported in increasing quantities. The value of the shipments to the United Kingdom in 1872 (largely exceeding those of any previous year) was £1,154,270. Of this sum, £986,796 represents the value of the oranges and lemons imported from Spain, Portugal, the Canary Islands and Azores; £155,330 the shipments of the same fruit from Italy; and £3,825 those from Malta.

Of concentrated _lemon juice_ there were exported in 1877 from Messina 1,631,332 kilogrammes, valued at 2,446,996 lire. The value of concentrated _lime juice_ exported in 1874 from Montserrat was £3,390. From Dominica, 11,285 gallons, value £1,825, were shipped in 1875.

[466] _Gazetta Chimica Italiana_, ii. (1872) 385; _Journ. of Chem. Soc._ xi (1873) 402.

[467] Stoddart’s statement that if potash be added to lemon juice, _oxalic acid_ may be detected in the mixture after a few days, is not supported by our observations.

=Uses=—Lemon peel is used in medicine solely as a flavouring ingredient. Freshly prepared lemon juice is often administered with an alkaline bicarbonate in the form of an effervescing draught, or in a free state.

Concentrated _lemon juice_ is imported for the purpose of making citric acid; it is derived not only from the lemon, but also, to a smaller extent, from the lime and bergamot. _Lime juice_ of the West Indies is chiefly used as a beverage; small quantities of it are also exported for the manufacture of citric acid. The culture of _Citrus Limetta_ Risso, the _lime_, was introduced in Montserrat in 1852.

OLEUM LIMONIS.

_Oleum Limonum_; _Essential Oil or Essence of Lemon_; F. _Essence de Citron_; G. _Citronenöl_.

=Botanical Origin=—_Citrus Limonum_ Risso (see p. 114).

=History=—The chemists of the 16th century were well acquainted with the method of extracting essential oils by distillation. Besson in his work _L’art et moyen parfaict de tirer huyles et eaux de tous medicaments simples et oleogineux_, published at Paris in 1571, mentions _lemon_-(citron) and orange-peel among the substances subjected to this process. Giovanni Battista Porta,[468] a learned Neapolitan writer, describes the method of preparing _Oleum ex corticibus Citri_ to consist in removing the peel of the fruit with a rasp and distilling it so comminuted with water; and adds that the oils of lemon and orange may be obtained in the same manner. Essence of lemon of two kinds, namely _expressed_ and _distilled_, was sold in Paris in the time of Pomet, 1692.

=Production=—Essential oil of lemon is manufactured in Sicily, at Reggio in Calabria, and at Mentone and Nice in France.

The lemons are used while still rather green and unripe, as being richer in oil than when quite mature. Only the small and irregular fruit, such as is not worth exporting, is employed for affording the essence.

The process followed in Sicily and Calabria may be thus described;[469] it is performed in the months of November and December.

[468] _Magiæ Naturalis libri xx._ Neapoli. 1589. 188.

[469] Through the kindness of Signor Mallandrino of Giampilieri near Messina, I had the pleasure of seeing how the essence is made. Though the time of my visit (13 May 1872) was not that of the manufacture, Signor M. sent for one of his workmen, and having procured a few lemons, set him to work on them in order that I might have ocular demonstration of the process.—D. H.

The workman first cuts off the peel in _three_ thick longitudinal slices, leaving the central pulp of a three-cornered shape with a little peel at either end. This central pulp he cuts transversely in the middle, throwing it on one side and the pieces of peel on the other. The latter are allowed to remain till the next day and are then treated thus: the workman seated holds in the palm of his left hand a flattish piece of sponge, wrapping it round his forefinger. With the other he places on the sponge one of the slices of peel, the outer surface downwards, and then presses the zest-side (which is uppermost) so as to give it for the moment a convex instead of a concave form. The vesicles are thus ruptured, and the oil which issues from them is received in the sponge with which they are in contact. Four or five squeezes are all the workman gives to each slice of peel, which done he throws it aside. Though each bit of peel has attached to it a small portion of pulp, the workman contrives to avoid pressing the latter. As the sponge gets saturated the workman wrings it forcibly, receiving its contents in a coarse earthen bowl provided with a spout; in this rude vessel, which is capable of holding at least three pints, the oil separates from the watery liquid which accompanies it and is then decanted.

The yield is stated to be very variable, 400 fruits affording 9 to 14 ounces of essence. The prisms of pulp and the exhausted pieces of peel are submitted to pressure in order to extract from them lemon juice, and are said to be also subjected to distillation. The foregoing is termed the _sponge-process_; it is also applied to the orange. It appears rude and wasteful, but when honestly performed it yields an excellent product.

Essence of lemon is prepared at Mentone and Nice by a different method. The object being to set free and to collect the oil contained in the vesicles of the peel, an apparatus is employed, which may be thus described:—a stout saucer or shallow basin of pewter, about 8½ inches in diameter with a lip on one side for convenience of pouring. Fixed in the bottom of this saucer are a number of stout, sharp, brass pins, standing up about half an inch; the centre of the bottom is deepened into a tube about an inch in diameter and five inches in length, closed at its lower end. This vessel, which is called an _écuelle à piquer_, has therefore some resemblance to a shallow, dish-shaped funnel, the tube of which is closed below.

The workman takes a lemon in the hand, and rubs it over the sharp pins, turning it round so that the oil-vessels of the entire surface may be punctured. The essential oil which is thus liberated is received in the saucer whence it flows down into the tube; and as this latter becomes filled, it is poured into another vessel that it may separate from the turbid aqueous liquid that accompanies it. It is finally filtered and is then known as _Essence de Citron au zeste_. A small additional produce is sometimes obtained by immersing the scarified lemons in warm water and separating the oil which floats off.

A second kind of essence termed _Essence de Citron distillée_ is obtained by rubbing the surface of fresh lemons, or of those which have been submitted to the process just described, on a coarse grater of tinned iron, by which the portion of peel richest in essential oil is removed. This grated peel is subjected to distillation with water, and yields a colourless essence of very inferior fragrance, which is sold at a low price.

=Description=[470]—The oil obtained by the sponge-process and that of the _écuelle à piquer_ are mobile liquids of a faint yellow colour, of exquisite fragrance and bitterish aromatic taste.

[470] For specimens of the _Essence au zeste_ and of the _Essence distillée_ of guaranteed purity we have to thank M. Médecin, distiller of essences, Mentone; and Messrs. G. Pannucio e figli, for an authentic sample of the essence made by the sponge process in their establishment at Reggio. We have also had a small quantity prepared by the _écuelle_ by one of ourselves near Mentone, 15th June 1872.—D. H.

The different specimens which we have examined are readily miscible with bisulphide of carbon, but dissolve sparingly in spirit of wine (0·830). An equal weight of the oil and of spirit of wine forms a turbid mixture. No peculiar coloration is produced by mixture with perchloride of iron.

The oils are dextrogyre, but differ in their rotatory power, as may be illustrated by the following results, which we obtained by examining them in a column 50 millimetres long in the polaristrobometer of Wild. The oil of Signori Panuccio, due to the sponge-process (p. 118, note 2), deviated 20·9°, that of Monsieur Médecin (_Essence de Citron au zeste_) obtained by the _éculle à piquer_ deviated 33·4° and his distilled oil 28·3°.

=Chemical Composition=—The prevailing portion of most essential oils of the _Aurantiaceæ_ agrees with the formula C₁₀H₁₆; the differences which they exhibit chiefly concern their optical properties, odour, and colour. The boiling point mostly varies from about 170° to 180° C., the sp. gr. between 0·83 and 0·88. These oils are a mixture of isomeric hydrocarbons, and also contain a small amount of cymene, C₁₀H₁₄, and of oxygenated oils, not yet well known; of these we may infer the presence either from analytical results or simply from the fact that the crude oils are altered by metallic sodium. If they are purified by repeated rectification over that metal, they are finally no longer altered by it. Oils thus purified cease to possess their original fragrance, and often resemble oil of turpentine, with which they agree in composition and general chemical behaviour.

As to essential oil of lemons, its chief constituent is the terpene, C₁₀H₁₆, which, like oil of turpentine, easily yields crystals of terpin, C₁₀H₁₆ 3OH₂. There is further present, according to Tilden (1879) another hydrocarbon, C₁₀H₁₆, which already boils at 160° C., whereas the foregoing boils at 176° C. Lastly a small amount of cymene and of a compound acetic ether, C₂H₃O(C₁₀H₁₇O), would appear to occur also in oil of lemons. The crude oil of lemons already yields the crystalline compound C₁₀H₁₆ + 2HCl, when saturated with anhydrous hydrochloric gas, whereas by the same treatment oil of turpentine affords the solid compound C₁₀H₁₆ + HCl.

Essential oil of lemons (not the distilled) when long kept deposits a greasy mass, from which we have obtained small crystals apparently of _Bergaptene_ (p. 123).

=Commerce=—Essence of lemons is shipped chiefly from Messina and Palermo, packed in copper bottles called in Italian _ramiere_ and by English druggists “_jars_” holding 25 to 50 kilo. or more; sometimes in tin bottles of smaller size. The quantity of essences of lemon, orange and bergamot exported from Sicily in 1871 was 368,800 lb., valued at £144,520, of which about two-thirds were shipped to England.[471] In 1877 the export of these essential oils from Messina amounted to 306,948 kilogrammes, valued at 6,130,960 lire.

[471] Consul Dennis, _On the Commerce, &c. of Sicily in 1869, 1870, 1871_. _Reports from H.M. Consuls_. No. 4. 1873.

=Uses=—Essence of lemon is used in perfumery, and as a flavouring ingredient; and though much sold by druggists is scarcely employed in medicine.

=Adulteration=—Few drugs are more rarely to be found in a state of purity than essence of lemon. In fact it is stated that almost all that comes into the market is more or less diluted with oil of turpentine or with the cheaper _distilled_ oil of lemons. Manufacturers of the essence complain that the demand for a cheap article forces them to this falsification of their product.

OLEUM BERGAMOTTÆ.

_Oleum Bergamii_; _Essence or Essential Oil of Bergamot_; F. _Essence de Bergamotte_; G. _Bergamottöl_.

=Botanical Origin=—_Citrus Bergamia_ var. _vulgaris_ Risso et Poiteau,[472] a small tree closely resembling in flowers and foliage the Bitter Orange. Its fruit is 2½ to 3 inches in diameter, nearly spherical, or slightly pear-shaped, frequently crowned by the persistent style; it is of a pale golden yellow like a lemon,[473] with the peel smooth and thin, abounding in essential oil of a peculiar fragrance; the pulp is pale yellowish green, of a bitterish taste, and far less acid than that of the lemon.

The tree is cultivated at Reggio in Calabria, and is unknown in a wild state.

=History=—The bergamot is one of the cultivated forms which abound in the genus _Citrus_, and which constitute the innumerable varieties of the orange, lemon and citron. Whether it is most nearly related to the lemon or to the orange is a point discussed as early as the beginning of the last century. Gallesio[474] remarks that it so evidently combines the characters of the two that it should be regarded as a hybrid between them. The bergamot first appeared in the latter part of the 17th century. It is not mentioned in the grand work on orange trees of Ferrari,[475] published at Rome in 1646, nor in the treatise of Commelyn[476] (1676), nor in the writings of Lanzoni (1690),[477] or La Quintinie (1692).[478] So far as we know, it is first noticed in a little book called _Le Parfumeur François_, printed at Lyons in 1693. The author who calls himself _Le Sieur Barbe, parfumeur_, says that the _Essence de Cedra ou Bergamotte_ is obtained from the fruits of a lemon-tree which has been grafted on the stem of a bergamot pear; he adds that it is got by squeezing small bits of the peel with the fingers in a bottle or globe large enough to allow the hand to enter.

[472] _Histoire naturelle des Orangers_, Paris, 1818. p. 111. tab. 53, or the same work, new edition, by Dubreuil, 1873, p. 82. We accept the name given by these authors for the sake of convenience and definiteness, and not because we concur in their opinion that the Bergamot deserves to be ranked as a distinct botanical species.

[473] Fig. in Bentley and Trimen, _Med. Plants_,