part 28

(1878).

[2705] _A. citratum_ A.P. De Candolle, _Catalogus Plantarum Horti Botanici Monspeliensis_, 1813; _A. Schœnanthus_ Wallich, _Plant. Asiat. rariores_, iii. (1832) tab. 280; Roxburgh, _Flora Indica_, i. (1820) 278, quoad observationes, sed non quoad diagnosis.

[2706] Ventenat, _Jardin de Cels_, 1803. tab. 89; _A. Martini_ Roxb. _Flor. Ind._ i. (1820) 280; _A. pachnodes_ Trinius, _Species Graminum_, iii. (1836) tab. 327; _A. Calamus aromaticus_ Royle, _Illustrations of Bot. of Himalayan Mountains_, 1839. tab. 97.

=History=—The aromatic properties of certain species of _Andropogon_ were well known to Rheede, Rumphius, and other early writers on Indian natural history; and an oil distilled from the _Sireh_ grass in Amboyna was known as a curiosity as early as 1717.[2707]

But it is only in very recent times that the volatile oils of these plants have become objects of commerce with Europe. Lemon grass oil is mentioned by Roxburgh in 1820 as being distilled in the Moluccas; and it was first imported into London about the year 1832. Citronella oil is of much more recent introduction. Ginger grass oil, called in Hindustani _Rúsa ka tel_, is stated by Waring[2708] to have been first brought to notice by Dr. N. Maxwell in 1825.

=Production=—Citronella and Lemon grass are cultivated about Galle and at Singapore, the same estate often producing both. The grasses are distilled separately, the essential oils being regarded as entirely distinct, and having different market values. In Ceylon they are cut for distillation at any time of year, but mostly in December and January.

On the Perseverance Estate at Gaylang, Singapore, belonging to Mr. John Fisher, an area of 950 acres is cultivated with aromatic grasses and other plants, for the production of essential oils. The manufacture was tried on a small scale in 1865, and has been so successful that an aggregate of 200 lb. of various essential oils is now produced _daily_. These oils are stated to be Citronella, Lemon Grass, Patchouly, Nutmeg, Mace, Pepper, and Oman (p. 302): and mint is now being cultivated.[2709]

Ginger grass oil is distilled in the collectorate of Khandesh in the Bombay Presidency. That produced in the district of Namár in the valley of the Nerbudda, is sometimes called _Grass Oil of Namar_. We have no particulars of the distillation, which however must be carried on extensively.

=Description=—The Indian grass oils are lighter than water, devoid of rotatory power when examined by polarized light, and do not alter litmus paper. They are all extremely fragrant, having an odour like a mixture of lemon and rose. Lemon grass, which in colour is a deep golden brown, has an odour resembling that of the sweet-scented verbena of the gardens, _Lippia citriodora_ H.B.K. Ginger grass oil, the colour of which varies from pale greenish yellow to yellowish-brown, has the odour of _Pelargonium Radula_ Aiton. The colour of citronella oil is a light greenish yellow. The manufacture of Winter of Ceylon, and of Fisher of Singapore, have a reputation for excellence, and are generally indicated by name in drug sale catalogues.

=Chemical Composition=—Stenhouse[2710] examined in 1844 oil of ginger grass given to him by Christison as _Oil of Namur_ (or _Nimar_). The sample was of deep yellow, and apparently old, for when mixed with water and subjected to distillation, it left nearly one half its bulk of a fluid resin, the oil which passed over being colourless. After rectification from chloride of calcium, it was shown to consist of a hydrocarbon mixed with a small proportion of an oxygenated oil. The latter having been decomposed by sodium, and the oil again rectified, a second analysis was made which proved it isomeric with oil of turpentine.

[2707] _Ephemerides Naturæ Curiosorum_, cent. v.-vi. (1717), appendix 157.

[2708] _Pharmacopœia of India_, 1868. 465.

[2709] _Straits Settlements Blue Book for 1872_, Singapore, 1873. 465.

[2710] _Mem. of Chem. Soc._ ii. (1845) 122.

A genuine grass oil from Khandesh, derived as we suppose from the same species, which was examined by one of us (F.), yielded nothing crystalline when saturated with dry hydrochloric acid; but when the liquid was afterwards treated with fuming nitric acid, crystals of the compound, C₁₀H₁₆, HCl, sublimed into the upper part of the vessel. We have observed that the oils both of lemon grass and citronella yield solid compounds, if shaken with a saturated solution of bisulphite of sodium.

Citronella oil was found by Gladstone (1872) to be composed chiefly of an oxidized oil, which he called _Citronellol_, and which he separated by fractional distillation into two portions, the one boiling at 202-205° C., the other 199-202° C. The composition of each portion is indicated by the formula C₁₀H₁₆O.

Wright’s researches (1874) tend rather to show the prevailing part of citronella oil to consist of the liquid C₁₀H₁₈O, boiling near 210°, which he calls _Citronellol_. It unites with bromine, and the resulting compound, upon heating, breaks up according to the following equation:—

C₁₀H₁₈OBr₂ = OH₂ · 2 HBr · C₁₀H₁₄. Cymene.

=Commerce=—The growing trade in grass oil is exemplified in a striking manner by the following statistics. The export of _Citronella Oil_ from Ceylon in 1864 was 622,000 ounces, valued at £8230. In the _Ceylon Blue Book_, the exports for 1872 are returned thus:—

To the United Kingdom 1,163,074 ounces} British India 5,713 ” } 1,595,257 United States of North America 426,470 ” } ounces.[2711]

In 1875 the oil shipped from Ceylon to the United Kingdom was valued at 42,871 rupees, that sent to other foreign countries at 45,871 rupees, to British possessions 660 rupees (one rupee equal to about 2_s._).

_Oil of Lemon Grass_, which is a more costly article and less extensively produced, was exported from Ceylon during the same year to the extent of 13,515 ounces, more than half of which quantity was shipped to the United States. There are no analogous statistics for these two oils from Singapore, where, as stated at p. 726, they are now largely manufactured.

By the official _Report on the External Commerce of Bombay_, published in 1867, we find that during the year ending 31 March, 1867, _Grass Oil_ [i.e. _Ginger Grass_ or _Rúsa Oil_] was exported thence to the amount of 41,643 lb. This oil is shipped to England and to the ports of the Red Sea.

=Uses=—Grass oils are much esteemed in India as an external application in rheumatism. Rúsa oil is said to stimulate the growth of the hair. Internally, grass oil is sometimes administered as a carminative in colic; and an infusion of the leaves of lemon grass is prescribed as a diaphoretic and stimulant. In Europe and America the oils are used almost exclusively by the soapmakers and perfumers.[2712]

[2711] In addition to which, there were “_842 dozens and 33 packages_” of the same oil shipped to the United States. One ounce equal to 31·1 grammes.

[2712] The foliage of the large odoriferous species of _Andropogon_ is used in India for thatching. It is eaten voraciously by cattle, whose flesh and milk become flavoured with its strong aroma.

But the most remarkable use made of any grass oil is that for adulterating _Attar of Rose_ in European Turkey. The oil thus employed is that of _Andropogon Schœnanthus_ L. (see p. 725); and it is a curious fact that its Hindustani name is closely similar in sound to the word _rose_. Thus under the designation _Rusa_, _Rowsah_, _Rosa_, _Rosé_, _Roshé_,[2713] it is exported in large quantities from Bombay to the ports of Arabia, probably chiefly to Jidda, whence it is carried to Turkey by the Mahommedan pilgrims. In Arabia and Turkey, it appears under the name _Idris yàghi_, while in the attar-producing districts of the Balkan it is known, at least to Europeans, as _Geranium Oil_ or _Palmarosa Oil_. Before being mixed with attar, the oil is subjected to a certain preparation, which is accomplished by shaking it with water acidulated with lemon juice, and then exposing it to the sun and air. By this process, described by Baur,[2714] the oil loses a penetrating after-smell, and acquires a pale straw-colour. The optical and chemical differences between grass oil thus refined and attar of rose are slight and do not indicate a small admixture of the former. If grass oil is added largely to attar, it will prevent its congealing.

=Adulteration=—The grass oil prepared by the natives of India is not unfrequently contaminated with fatty oil.

Other Products of the genus Andropogon.

=Herba Schœnanthi vel Squinanthi=, _Juncus odoratus_, _Fœnum Camelorum_.

The drug bearing these names has had a place in pharmacy from the days of Dioscorides down to the middle of the last century, and is still met with in the East. The plant which affords it, formerly confounded with other species, is now known to be _Andropogon laniger_ Desf., a grass of wide distribution, growing in hot dry regions in Northern Africa (Algeria), Arabia, and North-western India, reaching Thibet, where it is found up to an elevation of 11,000 feet. Mr. Tolbort has sent us specimens under the name of _Kháví_, gathered by himself in 1869 between Multán and Kot Sultán, and quite agreeing with the drug of pharmacy. The grass has an aromatic pungent taste, which is retained in very old specimens. We are not aware that it is distilled for essential oil.

=Cuscus or Vetti-ver=[2715]—This is the long fibrous root of _Andropogon muricatus_ Retz, a large grass found abundantly in rich moist ground in Southern India and Bengal. Inscriptions on copper-plates lately discovered in the district of Etawah, south-east of Agra, and dating from A.D. 1103 and 1174, record grants of villages to Brahmins by the kings of Kanauj, and enumerate the imposts that were to be levied. These include taxes on mines, salt pits and the trade in precious metals, also on mahwah (_Bassia_) and mango trees, and on _Cuscus Grass_.[2716]

[2713] 50 cases, containing about 2250 lb., imported from Bombay, were offered as “_Rose Oil_” at public sale, by a London drug-broker, 31 July, 1873.

[2714] See p. 267.

[2715] _Cuscus_, otherwise written _Khus-khus_, a name adopted by the English in India, is probably from the Persian _Khas_. _Vetti-ver_ is the Malyalim name of the plant.

[2716] _Proc. of Asiat. Soc. of Bengal_, Aug. 1873. 161.

Cuscus, which appears occasionally in the London drug sales, is used in England for laying in drawers as a perfume. In India it serves for making _tatties_ or screens, which are placed in windows and doorways, and when wetted, diffuse an agreeable odour and coolness. It is also used for making ornamental baskets and many small articles, and has some reputation as a medicine.

RHIZOMA GRAMINIS.

_Radix Graminis_; _Couch Grass_, _Quitch Grass_, _Dog’s Grass_; F. _Chiendent commun ou Petit Chiendent_; G. _Queckenwurzel_, _Graswurzel_.

=Botanical Origin=—_Agropyrum repens_ P. Beauv. (_Triticum repens_ L.), a widely diffused weed, growing in fields and waste places in all parts of Europe, in Northern Asia down to the region south of the Caspian, also in North America; and in South America to Patagonia and Tierra del Fuego.

=History=—The ancients were familiar with a grass termed [Greek Agrôstis] and _Gramen_, having a creeping rootstock like that under notice. It is impossible to determine to what species the plant is referable, though it is probable that the grass _Cynodon Dactylon_ Pers., as well as _Agropyrum repens_, was included under these names.

Dioscorides asserts that its root taken in the form of decoction, is a useful remedy in suppression of urine and vesical calculus. The same statements are made by Pliny; and again occur in the writings of Oribasius[2717] and Marcellus Empiricus[2718] in the 4th, and of Aëtius[2719] in the 6th century, and are repeated in the mediæval herbals,[2720] where also figures of the plant may be found, as for instance in Dodonæus. The drug is also met with in the German pharmaceutical tariffs of the 16th century. Turner[2721] and Gerarde both ascribe to a decoction of grass root diuretic and lithontriptic virtues. The drug is still a domestic remedy in great repute in France, being taken as a demulcent and sudorific in the form of _tisane_.

[2717] _De virtute simplicium_, cap. i. (Agrostis).

[2718] _De medicamentis_, cap. xxvi.

[2719] Tetrabibli primæ, sermo i.

[2720] As in the _Herbarius Pataviæ_ printed in 1485, in which it is said of _Gramen_—“aqua decoctionis ejus ... valet contra dissuriam ... et frangit lapidem et curat vulnera vesicæ et provocat urinam....”

[2721] _Herball_,