LEMON, the fruit of Citrus Limonum, Eisso, which is regarded by some botanists as a variety of Citrus medica, L. The wild stock of the lemon tree is a native of the valleys of Kumaon and Sikkim in the North-West Provinces of India, ascending the mountains to a height of 4000 feet, and occurring under several forms.
The lemon seems to have been unknown to the ancient Greeks and Romans, and to have been introduced by the Arabs into Spain between the 12th and 13 th centuries. In 1494 the fruit was cultivated in the Azores, and largely shipped to England, but since 1838 the exportation has ceased. As a cultivated plant the lemon is now met with throughout the Mediterranean region, in Spain and Portu-gal, in California and Florida, and in almost all tropical and subtropical countries. Like the apple and pear, it varies exceedingly under cultivation. Risso and Poiteau enumerate forty-seven varieties of this fruit, although they maintain as distinct the sweet lime, Citrus Limetta, Risso, with eight varieties, and the sweet lemon, Citrus Lumia, Risso, which differ only in the fruit possessing an insipid instead of an acid juice, with twelve varieties.
The lemon is more delicate than the orange, although, according to Humboldt, both require an annual mean temperature of 62° Fahr. Unlike the orange, which presents a fine close head of deep green foliage, it forms a straggling bush, or small tree, 10 to 12 feet high, with paler, more scattered leaves, and short angular branches with sharp spines in the axils. The flowers, which possess a sweet odour quite distinct from that of the orange, are in part hermaphrodite and in part unisexual, the outside of the corolla having a purplish hue. The fruit, which is usually crowned with a nipple, consists of an outer rind or peel, the surface of which is more or less rough from the convex oil receptacles imbedded in it, and of a white inner rind, which is spongy and nearly tasteless, the whole of the inte-rior of the fruit being filled with soft parenchymatous tissue, divided into about ten to twelve compartments, each gene-rally containing two or three seeds. The white inner rind varies much in thickness in different kinds, but is never so thick as in the citron. As lemons are much more profitable to grow than oranges, on account of their keeping properties, and from their being less liable to injury during voyages, the cultivation of the lemon is preferred in Italy wherever it will succeed. In damp valleys it is liable to be attacked by a fungus called "charbon" (Dematium monophyllum), the stem, leaves, and fruit becoming covered with a blackish dust. This is said to be coincident with or subsequent to the attacks of a small oval brown insect, Ghermes hesperidum, L. Trees grown in the shade, and not properly exposed to sunlight and air, suffer most severely from these pests. Syringing with milk of lime when the young insects are hatched, and before they have fixed themselves to the plant, seems to be the most effectual remedy known. Since the year 1875 this fungoid disease has made great ravages in Sicily among the lemon and citron trees, especially around Catania and Messina. M. Heritte attributes the prevalence of the disease to the fact that the growers have induced an unnatural degree of fertility in the trees, permitting them to bear enormous crops year after year. This loss of vitality is in some measure met by grafting healthy scions of the lemon on the bitter orange, but trees so grafted do not bear fruit until they are eight or ten years old.
The lemon tree is said to be exceedingly fruitful, a large one in Spain or Sicily ripening as many as three thousand fruits in favourable seasons. In the south of Europe lemons are collected more or less during every month of the year, but in Sicily the chief harvest takes place from the end of October to the end of December, those gathered during the last two months of the year being considered the best for keeping purposes. The fruit is gathered while still green. After collection the finest specimens are picked out and packed in cases, each containing about four hundred and twenty fruits, and also in boxes, three of which are equal to two cases, each lemon being separately-packed in paper. The remainder, consisting of ill-shaped or unsound fruits, are reserved for the manufacture of the essential oil and juice. The whole of the sound lemons collected are usually packed in boxes, but those which are not exported immediately are carefully picked over and the unsound ones removed before shipment. The exporta-tion is continued as required until April and May. The large lemons with a rougher rind, which appear in the London market in July and August, are grown at Sorrento near Naples, and in this case are allowed to remain on the trees until ripe.
Candied lemon peel is usually made in England from a larger variety of the lemon cultivated in Sicily on higher ground than the common kind, from which it is distinguished by its thicker rind and larger size. This kind, known as the Spadaforese lemon, is also allowed to remain on the trees until ripe, and when gathered the fruit is cut in half longitudinally and pickled in brine, before being exported in casks. Before candying the lemons are soaked in fresh water to remove the salt. Citrons are also exported from Sicily in the same way, but these are about six times as expensive as lemons, and a comparatively small quantity is shipped. Besides those exported from Messina and Palermo, lemons are also imported into England to a less extent from the Biviera of Genoa, and from Malaga in Spain, the latter being the most esteemed. Of the numerous varieties the wax lemon, the imperial lemon, and the Gaeta lemon are considered to be the best.
The Greek island of Andros is said to produce ten millions of lemons annually; these are exported chiefly to Constantinople, the Black Sea, and the Danube, realizing an average price of £1 to £1, 3s. per thousand.
Until recently the United States have been large im-porters of lemons, at good prices, from the Mediterranean. In 1878 Palermo exported 463,977 boxes of this fruit, at 6s. 6d. per box. Owing to increased facilities for transit, and the hazardous character of the trade, the lemons are now chiefly exported by the proprietors of small plantations, who, in their eagerness to dispose of their stock, glut the market at New York and Philadelphia, and sometimes find the speculation a ruinous one.
For some years past lemons have been extensively cultivated in the south of California, and the new industry will probably affect the Mediterranean trade to a serious extent. In 1874 half a million Californian lemons were received in San Francisco. Since it was found that, with a little care in the selection of the soil, these trees could be grown throughout the State, they have been planted in immense numbers, and the produce of each tree has been found to bring from 30s. to 60s. It has been esti-mated that in a few years the produce will be equal to the requirements of the Pacific States _md Territories, and that ultimately the whole of the United States may be supplied with lemons from California. In east Florida also, where suitable land is obtainable at 15 to 20 dollars an acre, lemons, limes, citrons, and more especially oranges, are being raised in abundance. In New South Wales lemons are also grown, having been introduced into Sydney about the year 1790.
Lemons of ordinary size contain about 2 ounces of juice, of specific gravity 1'039-1'046, yielding on an average 32-5 to 42'53 grains of citric acid per ounce. The amount of this acid, according to Stoddart, varies in different seasons, decreasing in lemons kept from February to July, at first slowly and afterwards rapidly, until at the end of that period it is all split up into glucose and carbonic acid,the specific gravity of the juice being in February 1'046, in May 1-041, and in July P027, while the fruit is hardly altered in appearance. Mr Geo. Mee, however, states that lemons may be kept for some months with scarcely perceptible deterioration by varnish-ing them with an alcoholic solution of shellacthe coating thus formed being easily removed when the fruit is required for household use by gently kneading it in the hands. Besides citric acid, lemon juice contains 3 to 4 per cent, of gum and sugar, albuminoid matters, and 2'28 percent, of inorganic salts. Cossa has determined that the ash of dried lemon juice contains 54 per cent, of potash, besides 15 per cent, of phosphoric acid. In the white portion of the peel (in common with other fruits of the genus) a bitter principle called hesperidine has been found. It is very slightly soluble in boiling water, but is soluble in dilute alcohol and in alkaline solutions, which it soon turns of a yellow or reddish colour. It is also darkened by tincture of perchloride of iron. Another substance named lemonine, crystallizing in lustrous plates, was discovered in 1879 by Palerno and Aglialoro in the seeds, in which it is present in very small quantity, 15,000 grains of the seed yielding only 80 grains of it. From hesperidine it differs in dissolving in potash without alteration. It melts at 275°.
Various modes of preserving lemon juice in small quantities for medicinal or domestic use have been suggested. Mr Judicis states that if allowed to deposit and then filtered through paper it keeps well. Dr Symes recommends heating the juice to loO^ahr., filling bottles with it at that temperature, and immediately closing them when perfectly full so as to keep out access of air. Another writer advises the addition of 10 per cent, of alcohol. Perhaps the most simple method is to keep it covered with a layer of olive or almond oil in a closed vessel furnished with a glass tap, by which the clear liquid may be drawn off as required.
As a commercial article for use on shipboard as a preventive of scurvy, lemon juice is largely consumed. By the provisions of the Act of Parliament 30 & 31 Vict. c. 124, § 4, every ship going to other countries where lemon or lime juice cannot be obtained is required to take sufficient to give 1 ounce to every member of the crew daily. Of this juice it requires about 13,000 lemons to yield 1 pipe (108 gallons). Sicilian juice in November yields about 9 ounces of crude citric acid per gallon, but only 6 ounces if the fruit is collected in April. The crude juice was formerly exported to England, and was often adulterated with sea-water, but is now almost entirely replaced by lime juice. It is said, however, to he still an article of considerable export from Turkey, where lemons are abundantly grown, to Odessa. But a concentrated lemon juice for the manufacture of citric acid is prepared in considerable quantities, chiefly at Messina and Palermo, by boiling down the crude juice in copper vessels over an open fire until its specific gravity is about 1 '239, seven to ten pipes of raw making only one of concentrated lemon juice. Of this concentrated juice Messina exported in 1877 1,631,332 kilogrammes, valued at 2,446,996 lire, and in 1878 Naples exported it to the value of £767.
Lemon juice for this purpose is prepared also from the fruits of limes and Bergamot oranges. It is said to be sometimes adulter-ated with sulphuric acid on arrival in England.
Essence or Essential Oil of Lemon.The essential oil contained in the rind of the lemon also occurs in commerce as a distinct article. It is manufactured chiefly in Sicily, at Reggio in Calabria, and at Mentone and Nice in France. The small and irregularly shaped fruits are employed while still green, in which state the yield of oil is greater than when they are quite ripe. In Sicily and Calabria the oil is extracted in November and December, as follows. A workman cuts three longitudinal slices off each lemon, leaving a three-cornered central core having a small portion of rind at the apex and base. These pieces are then divided transversely and cast on one side, and the strips of peel are thrown in another place. Next day the pieces of peel are deprived of their oil by pressing four or five times successively the outer surface of the peel (zest or flavedo) bent into a convex shape, against a flat sponge held in the palm of the left hand and wrapped round the forefinger. The oil vesicles in the rind, which are ruptured more easily in the fresh fruit than in the state in which lemons are imported, yield up their oil to the sponge, which when saturated is squeezed into an earthen vessel furnished with a spout and capable of holding about three pints. After a time the oil separates from the watery liquid which accom-panies it, and is then decanted. By this process four hundred fruits yield 9 to 14 ounces of essence. The prisms of pulp are afterwards expressed to obtain lemon juice, and then distilled to obtain the small quantity of volatile oil they contain. At Mentone and Nice a different process is adopted. The lemons are placed in an écuelle à piquer, a shallow basin of pewter about 8J inches in diameter, having a lip for pouring on one side and a closed tube at the bottom about 5 inches long and 1 inch in diameter. A number of stout brass pins stand up about half an inch from the bottom of the vessel. The workman rubs a lemon over these pins, which rupture the oil vesicles, and the oil collects in the tube, which when it becomes full is emptied into another vessel that it may separate from the aqueous liquid mixed with it. When filtered it is known as Essence de Citron au Zeste, or, in the English market as perfumers' essence of lemon, inferior qualities being distinguished as druggists' essence of lemon. An additional product is obtained by immersing the scarified lemons in warm water and separating the oil which floats off. Essence de Citron distillée is obtained by rubbing the surface of fresh lemons (or of those which have been submitted to the action of the écuelle à piquer) on a coarse grater of tinned iron, and distilling the grated peel. The oil so obtained is colourless, and of inferior fragrance, and is sold at a lower price, while that obtained by the cold processes has a yellow colour and powerful odour.
Essence of lemon is chiefly brought from Messina and Palermo packed in copper bottles holding 25 to 50 kilogrammes or more, and sometimes in tinned bottles of smaller size. It is said to be rarely found in a state of purity in commerce, almost all that comes into the market being diluted with the cheaper distilled oil. This fact may be considered as proved by the price at which the essence of lemon is sold in England, this being less than it costs the manu-facturer to make it. When long kept the essence deposits a white greasy stearoptene, apparently identical with the bergaptene ob-tained from the essential oil of the Bergamot orange. The chief constituent of oil of lemon is the terpene, C10H16, boiling at 348°'8 Fahr., which, like oil of turpentine, readily yields crystals of terpin, CI0H163OH2, but differs in yielding the crystalline compound, C10H16 + 2C1, oil of turpentine forming one having the formula C10H16 + HC1. Oil of lemons also contains, according to Tilden, another hydrocarbon C10Hi6, boiling at 3 20° Fahr., a small amount of cymene, and a compound acetic ether, C2H30. C10H17O. The natural essence of lemon not being wholly soluble in rectified spirit of wine, an essence for culinary purposes is sometimes prepared by digesting 6 ounces of lemon peel in one pint of pure alcohol of 95 per cent., and, when the rind has become brittle, which takes place in about two and a half hours, powdering it and percolating the alcohol through it. This article is known as lemon flavour.
The name lemon is also applied to some other fruits. The Java lemon is the fruit of Citrus javanica, Bl., the pear lemon of a variety of Citrus Limetta, and the pearl lemon of Citrus margarita. The fruit of a passion-flower, Passiflora laurifolia, is sometimes known as the water-lemon, and that of a Berberi-daceous plant, Podophyllum peltatum, as the wild lemon. In France and Germany the lemon is known as the citron, and hence much confusion arises concerning the fruits referred to in different works. The essential oil known as oil of cedrat is usually a factitious article instead of being prepared, as its name implies, from the citron (Fr. cédratier). An essential oil is also prepared from Citrus Lumia, Risso, at Squillaee in Calabria, and has an odour like that of Bergamot but less powerful.
The juice of the sweet lime (Citrus Limetta, Risso), which is now largely substituted in the British navy for lemon juice for the pre-vention of scurvy, is imported principally from Montserrat. This island, although it only contains an area of 47 square miles, possesses the most extensive and best cultivated plantations of limes, Citrus Limetta, in the world. About thirty years ago a small plantation was commenced in the island by Mr Burke, at considerable outlay and with no prospect of an immediate return, and hence was not at first attended with success. But the Montserrat Lime Juice Co. now owns 600 acres, bearing 120,000 trees. Although the fruit is collected all the year round, it is never gathered from the trees, but gangs of women labourers are sent out about 5 o'clock in the morning to collect all the fallen fruit. These when brought home are immedi-ately sorted into sound and unsound fruits. The sound fruits are then bruised by hand in an écuelle, a saucer-like vessel with a num-ber of projections arising from its bottom ; by this means the oil cells in the rind are ruptured and the oil collects at the bottom of the vessel. More oil may be obtained from green fruits, but these yield less juice and less citric acid, and are therefore not gathered. The limes are then placed in a hopper with a sliding bottom through which they are supplied to two revolving rollers of gun-metal fur-nished with projecting spikes of different lengths. By these the fruit is torn to small pieces, which fall on a coarse copper sieve placed below. After passing through this strainer the juice is run directly into oaken puncheons or casks containing 100 gallons. These casks are filled quite full so as to exclude air, and bunged down immediately,the small proportion of essential oil contained in the vegetable matter which passes through the sieve helping to preserve the juice from decomposition. The slightly musty flavour of lime jnice is produced by keeping, even after a few days, although the fresh juice is quite free from it. The whole of the limes collected in the morning must be pressed for lime juice the same day, as the juice rapidly loses citric acid when exposed to the air, even as much as 3 ounces in one day, or the whole of the acid in three weeks. Even when run at once into the casks, although it may contain 13 or 14 ounces or rarely 15 ounces of citric acid per gallon, it seldom contains more than 9 or 10 ounces on arrival in England. The mass of fruit pulp, &c, remaining on the sieves is put in bags of coir or cocoa-nut fibre, and a number of these placed one upon another, with strainers between, are then submitted to strong pressure in a screw press, to obtain more juice, the marc left after expression being returned to the plantation as manure. The unsound limes are treated in like manner and the juice boiled down in copper pans to a consistence of about 40° (Twaddle), a loss of citric acid taking place if the liquor be further concentrated. It then forms a black fluid of a consistence approaching that of treacle, and is exported in casks to England for the manufacture of citric acid. Turbines of sixteen horse-power are used as the motors for the machinery. Although the lime begins to bear in three or four years, until the trees are seven or eight years old the crops are very small. The trees require pruning and attention to keep them free from a species of mistletoe with red or yellow berries and a kind of dodder. They are usually manured with cotton seed cake. A fungus resembling black dust, and apparently the same as that which attacks the lemon trees in Europe, occasionally injures the plantations. For these reasons they are continually being extended. The young plants are grown from seeds picked out of the straining sieves, and are planted about 15 yards apart. In the plantations in the higher parts of the island the limes show a tendency to assume the form of a lemon and to become thicker skinned, while nearer the sea they are smaller, more globular, and thinner skinned. The young leaves of the lime are used for per-fuming the water in finger-glasses, a few being placed in the water and bruised before use. In 1874 concentrated lime juice was exported from Montserrat to the value of £3390 ; and in 1878 Surinam exported 34,900 litres of lime juice. From Dominica 11,285 gallons, valued at £1825, were shipped in 1875. . Other trees belonging to the same natural order to which the name of limes have been given are Citrus aeida, and Atalantia monophylla, the wild lime of the Hindus. Nyssa candicans, the ogeechee lime of North America, and Tilia europssa, the common lime or linden tree, belong to other natural orders.
See Pharmacographia, 2d ed., p. 114; Bentley and Trimen, Medicinal Plants, 54 ; Risso and Poiteau. Histoire naturelle des Orangers, 1873 ; Alfonso, Collivazione degli Agrumi, 1875. (E. M. H.)