1902 Encyclopedia > Hemp


HEMP, Cannabis sativa, an annual herb, having angular rough stems and alternate lobed leaves. The bast fibres of Cannabis are the hemp of commerce, but under the name of hemp fibrous products from many different plants are often included. Sunn hemp is the bast fibre of a papilio-naceous plant, Crotolaria juncea, of India and the Sunda Islands ; Hibiscus cannabinus, an Indian malvaceous plant, yields brown or Bombay hemp; Jute or Paut hemp is pro-duced by Corchorus capsnlaris and C. olitorius, and to some extent by C. fuscus, C. Jascicularis, and C. decem-angulatus. Manila hemp or feather fibre is derived from the fibro-vascular bundles of certain monocotyledons, namely, several species of Musa, chiefly from M. textilis, but to some extent from M. sapientum, M. ensete, M. minda-nensis, and M. Gavendishii, in India, New Guinea, the Philippines, &c. Pita hemp is produced from certain species of Agave; the Aloe sisalina of Central America yields grass-hemp; and Murva or bowstring-hemp is obtained from an aloe-like plant, Sanseviera zeylanica, in Bengal, Ceylon, Java, and southern China.

The hemp plant, like the hop, which is the other member of the same natural order, Cannabinacece, is dioecious, that is, the male and female flowers are borne on separate plants. The male plant is smaller than the female, and ripens and dies earlier in the summer. The foliage of the female plant is darker and more luxuriant than that of the male. The leaves of hemp are constituted of 5 to 7 leaflets, the form of which is lanceolate-acuminate, and sharply serrate. The loose panicles of male flowers and the short spikes of female flowers arise from the axils of the upper leaves. The height of the plant varies greatly with season, soil, and manuring; a variety (C. saliva, var. gigantea) has produced specimens over 17 feet in height, but the.average height of the common sort is about 8 to 10 feet. There is but one species of hemp known, Cannabis sativa, the G. indica, Lam., and C. chinensis, Delile, owing their differences to climate, and losing many of their peculiarities when cultivated in temperate regions. Rumphius (in the 17th century) had noticed these differences between Indian and European hemp.

The original country of the hemp-plant was doubtless in some part of temperate Asia, probably near the Caspian Sea. It spread westward throughout Europe, and south-ward through the Indian peninsula.

Wild hemp still grows on the banks of the Lower Ural and the Volga, near the Caspian Sea. It extends to Persia, the Altai range, and northern and western China. It is found in Kashmir, and on the Himalaya, growing vigor-ously as far up as 6000 or even 10,000 feet.

Hemp is grown for three products—(1) the fibre of its stem ; (2) the resinous secretion which is developed in hot countries upon its leaves and flowering heads ; (3) its oily seeds.

Hemp has been employed for its fibre from ancient times. Herodotus (iv. 74) mentions the wild and culti-vated hemp of Scythia, and describes the hempen garments made by the Thracians as equal to linen in fineness. Hesychius says the Thracian women made sheets of hemp. Moschion (about 200 B.C.) records the use of hempen ropes for rigging the ship " Syracusia " built for Hiero II. The hemp plant has been cultivated in northern India from a considerable antiquity, not only as a drug but for its fibre. The Anglo-Saxons were well acquainted with the mode of preparing hemp. Hempen cloth became common in central and southern Europe in the 13th century.

The medicinal and intoxicating properties of hemp have probably been known in Oriental countries from a very early period. An ancient Chinese herbal, part of which was written about the 5th century B.C., while the remainder is of still earlier date, notices the seed and flower-bearing kinds of hemp. Other early writers refer to hemp as a remedy. The medicinal and dietetic use of hemp spread through India, Persia, and Arabia in the early Middle Ages. The use of hemp (bhang) in India was noticed by Garcia d'Orta in 15G3. Berlu in his Treasury of Drugs (1690) describes it as of " an infatuating quality and per-nicious use." Attention was recalled to this drug, in conse-quence of Napoleon's Egyptian expedition, by De Sacy (1809) and Rouger (1810). Its modern medicinal use is chiefly due to trials by Dr O'Shaughnessy in Calcutta (1838-1842). The plant is grown partly and often mainly for the sake of its resin in Persia, northern India, and Arabia, in many parts of Africa, and in Brazil.

The hemp plant grown in some parts of the United States yields the active resin so freely that less than 1 grain of the extract is a full dose. But it is as a fibre-producer that the hemp is now being more extensively cultivated in the United States. Hemp seeds were ordered for Plymouth colony as early as 1629, but the greater profit derivable from tobacco has always opposed the development of hemp-growing. The plant is chiefly grown in the States of Kentucky, Missouri, Tennessee, Ohio, Indiana, and New York. The produce of Kentucky in 1877 was 6140 tons. According to the census of 1870 the total production of the United States was 12,746 tons. In the northern part of the State of New York the crop is valued chiefly for the seeds, which may be from 20 to 40 bushels or more per acre. The produce per acre in the United States is from 700 to 1000 lb of fibre, 4 to 6 pecks of seed being usually sown.

Although the hemp-plant is grown in India chiefly for the production of its narcotic or intoxicating resin, yet a good deal of true hemp fibre is produced there. It is imported into England, however, chiefly from Bussia, the United States, Italy, Holland, Germany, Hungary, and Turkey. It is grown in Ireland, and in some parts (Suffolk and Lincolnshire) of England. It thrives well in Algeria. It requires a rich deep soil and heavy .manuring, and is an exhausting crop. In Great Britain about 6 pecks of seed per acre are drilled, 18 inches apart, in the middle of April. The male plants are pulled from the end of July to the end of August, the female or seed-bearing plants being gathered in September.

The British imports of hemp cannot he ascertained with accuracy, as the official returns include under that name the fibres of many hemp-substitutes. The following statement of hemp imported into the United Kingdom must therefore be taken with all necessary reserve:—
1873 1,247,354 cwts. 1876 1,174,859 cwts.
1874 1,240,168 ,, 1877 1,254,667 ,,
1875 1,350,758 ,, 1878 1,229,569 „

The following table gives the sources whence the supplies were chiefly drawn in the year 1877. But it must be again observed that the figures given for the imports from India, the Philippines, and other places to a less degree, include Manila hemp, Sunn hemp, and other spurious hemps.

Imports of Hemp into the United Kingdom in 1877.


paulins, canvas, and sailcloth. The finest hemp comes from Italy, but it is almost equalled by the higher qualities of the Russian fibre. Russian hemp varies much in price, according to quality and market fluctuations; its price in November 1879 was from £23 to £25 pel ton, Italian or garden hemp fetching from £38 to £41.

In order to free the fibre of the hemp plant from the soft and useless parenchyma and the tissues of the bark, the stems are sub-mitted to nearly the same processes as those described in the article FLAX. They are dried, beaten, or crushed in a hemp mill, and fermented or retted, preferably in soft water, after which they are again beaten with wooden mallets or in a specially constructed machine called a break. After breaking the stems are scutched, and thus the separation of the fibres furthered by the rubbing and striking to which they are subjected. The fibres are then hackled or combed.

i According to "Vetillart, the average length of European hemp fibres is '86 inch, the extremes being '2 and 2'1 inches. Dr M'Nab gives '0005 to '0007 inch as the diameter of fibres, the central cavity being "0001 in breadth. Under the microscope hemp fibres resemble those of flax, both being bast-fibres, and differ widely from those of Manila hemp or New Zealand flax; they are longitudinally striated cylinders, sometimes free and sometimes associated in small bundles. A hemp cord of 1 square millimetre section will bear, according to Haberlandt, an average weight of 34'5 kilogrammes without breaking—sometimes as much as 50 kilos.

The chief constituent of the fibre of hemp is of course cellulose, but small quantities of other substances are always present— the purest sorts, however, being richest in cellulose. A fine sample of Italian hemp gave on analysis the following percentages— water 8'9, wax 0'6, ash 0'8, matters soluble in water 3"5, lignose, albuminoids, &c., 8'4, cellulose 77'8. An ordinary sample of Russian hemp contained no less than 10'5 per cent, of moisture, and 1'5 of mineral matter, with but 72 of pure cellulose. By boiling a portion of this sample for four hours with water in a sealed tube at 150° C, a soluble extract amounting to TVth of the original hemp was ob-tained, Manila hemp giving 15p4 per cent., and Phormium fibre no less than 19 per cent., when similarly treated. Dilute solutions of iodine and sulphuric acid, successively applied, give to hemp fibres a greenish hue. The ash of hemp is rich in lime.

Hemp-resin. —Hemp as a drug or intoxicant for smoking and chewing occurs in the three forms of bhang, ganja, and charas.

(1) Bhang, the Hindustani siddhi or sabzi, consists of the dried leaves and small stalks of the hemp ; a few fruits occur in it. It is of a dark brownish-green colour, and has a faint peculiar odour and but a slight taste. It is smoked with or without tobacco; or it is made into a sweetmeat with honey, sugar, and aromatic spices ; or it is powdered and infused in cold water, yielding a tur-bid drink, subdschi. Hashish is one of the Arabic names given to the Syrian and Turkish preparations of the resin-ous hemp leaves. One of the commonest of these prepar-ations is made by heating the bhang with water and butter, the butter becoming thus charged with the resinous and active substances of the plant.

(2) Ganja, the guaza of the London brokers, consists of the flowering and fruiting heads of the female plant. It is brownish-green, and otherwise resembles bhang, as in odour and taste. Some of the more esteemed kinds of hashish are prepared from this ganja. Ganja is met with in the Indian bazaars in dense bundles of 24 plants or heads apiece. The hashish in such extensive use in Central Asia is often seen in the bazaars of large cities in the form of cakes, 1 to 3 inches thick, 5 to 10 inches broad, and 10 to 15 inches long.

Charas, or churrus, is the resin itself collected, as it exudes naturally from the plant, in different ways. The best sort is gathered by the hand like opium ; sometimes the resinous exudation of the plant is made to stick first of all to cloths, or to the leather garments of men, or even to their skin, and is then removed by scraping, and afterwards con-solidated by kneading, pressing, and rolling. It contains about one-third or one-fourth its weight of the resin. But the churrus prepared by different methods and in different countries differs greatly in appearance and purity. Some-times it takes the form of egg-like masses of greyish-brown colour, having when of high quality a shining resinous fracture. Often it occurs in the form of irregular friable lumps, like pieces of impure linseed oil-cake.

Hemp, however consumed, acts in a most strange way upon the nervous system, but its effects differ greatly with races as well as with individuals. Generally the first effect of a small dose is to produce increase of appetite and cheerfulness. Larger doses produce hallucinations, delirium, sleep, and sometimes catalepsy. During the dreamy state induced by an average dose of hashish, the patient becomes the sport of rapidly shifting ideas. Errors of perception as to time and place are a conspicuous characteristic of its effects on the mind. For the connexion of the name assassin with hashish, see vol. ii. p. 723.

Extract of hemp has been repeatedly tried in modern European medical practice without very consistent or satis-factory results. It has antispasmodic and anodyne char-acters, and has been employed in tetanus, spasmodic cough, hydrophobia, and some forms of mania. It is a quieter of the nervous system, but does not cause constipation, check the appetite, nor diminish the secretions like opium.

Hemp is very largely used in Eastern countries as an intoxicant and narcotic—probably by nearly 300 millions of the human race. The amount consumed cannot be esti-mated. Of dried hemp and churrus there was sent in 1876 not less than £86,000 worth through the Khyber Pass into British India.

There are three substances in the hemp-drug to which its activity has been attributed. Of these the resin, separated and investigated by Messrs T. & H. Smith, is the most abundant and probably the most important, and yet its chemical nature and properties are by no means certain. It is soluble in alcohol, and has a warm, bitter, acrid taste with a slight odour. It melts between 70° and 90° C., and has a pale brown colour. It is called cannabin. Cannabene is the volatile oil of Indian hemp obtained by distilling ganja or churrus with water. Its composition is represented by C9H10; it boils between 235° and 240°. Cannabene is accompanied by a crystalline hydrocarbon containing 84 per cent, carbon and 16 per cent, hydrogen. The supposed occurrence of nicotine in Indian hemp has not been confirmed, and would not in any way suffice to explain the properties of the drug. Moreover, tobacco- is often added to hemp. That there is a volatile alkaloid in hemp, though in small quantities, is, however, established beyond doubt. The proportion of pure resin in ganja was found by Messrs T. & H. Smith to be 6 or 7 per cent. Gastinell gives 3 per cent, as obtain-able from Egyptian hemp. The volatile oil in fresh hemp pro-bably does not exceed 3 parts in 1000. By treating the commercial resinous extract of Indian hemp with strong nitric acid, Bolas and Francis obtained (Journ. Cliem. Soc, vol. vii., n. s., p. 417) an oxidation product, soluble in alcohol and crystallizing in long flat prisms. The formula C5H602 has been assigned to this substance, which is known as oxycannabin.

Hemp Seed, Cake, and Oil. _—The ripe seeds, really fruits, being nuts or achenes of the hemp plant, contain about 34 per cent, of oil and 16 of albuminoids. When the crushed seeds have been submitted to pressure, the re-sidual cake is found to retain about 7 per cent, of oil. The value of hemp cake as a cattle-food is lessened by its purgative property. The seeds are much used as a food for singing birds. A hundred parts of the seed yield from 70 to 75 of cake and 25 to 30 of oil. This oil has drying properties, though it is in this respect much inferior to linseed oil. Its specific gravity is '9307. The seeds are roundish ovate, about -J- inch in length, and of a dark grey colour, with a pale ash-coloured network of surface-markings.

See Bentley and Trimen's Medicinal Plants, No. 231 ; Vetillart's Jhtudes sur les fibres textiles, pp. 72-87 ; Dickson's Fibre Plants of India; Boyle's Fibrous Plants of India; Cultivation of Hemp in India; Dr O'Shaughnessy's Preparation of Indian Hemp or Gunjah;
Yates's Textrinum Antiquorum; Hugo Miiller's Pflanzenfaser; the Dispensatory of the United States; Knight's Dictionary of Mechanics; Dr G. Martius's Studien über den Hanf; and Johnston's Chemistry of Common Life, 1879. (A. H. C.)

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