SACCHARUM.

Sugar, Cane-Sugar, Sucrose; F. Sucre, Sucre de canne; G. Zucker, Rohrzucker.

Botanical Origin—Saccharum officinarum L., the Sugar Cane. The jointed stem is from 6 to 12 feet high, solid, hard, dense, internally juicy, and hollow only in the flowering tops. Several varieties are cultivated, as the Country Cane, the original form of the species; the Ribbon Cane, with purple or yellow stripes along the stem; the Bourbon or Tahiti Cane, a more elongated, stronger, more hairy and very productive variety. Saccharum violaceum Tussac, the Batavian Cane, is also considered to be a variety; but the large S. chinense Roxb. introduced from Canton in 1796 into the Botanic Gardens of Calcutta, may be a distinct species; it has a long, slender, erect panicle, while that of S. officinarum is hairy and spreading, with the ramifications alternate and more compound, not to mention other differences in the leaves and flowers.

The sugar cane is cultivated from cuttings, the small seeds very seldom ripening. It succeeds in almost all tropical and subtropical countries, reaching in South America and Mexico an elevation above the sea of 5000-6000 feet. It is cultivated in most parts of India and China up to 30-31° N. lat, the mountainous regions excepted.

From the elaborate investigations of Ritter,[2660] it appears that Saccharum officinarum was originally a native of Bengal, and of the Indo-Chinese countries, as well as of Borneo, Java, Bali, Celebes, and other islands of the Malay Archipelago. But there is no evidence that it is now found any where in a wild state.

History[2661]—The sugar cane was doubtless known in India from time immemorial, and grown for food as it still is at the present day, chiefly in those regions which are unsuited for the manufacture of sugar.[2662]

Herodotus, Theophrastus, Seneca, Strabo, and other early writers had some knowledge of raw sugar, which they speak of as the Honey of Canes or Honey made by human hands, not that of bees; but it was not until the commencement of the Christian era, that the ancients manifested an undoubted acquaintance with sugar, under the name of Saccharon.

Thus Dioscorides[2663] about a.d. 77 mentions the concreted honey called Σάκχαρον found upon canes (ὲπὶ τῶν καλάμων) in India and Arabia Felix, and which in substance and brittleness resemble salt. Pliny evidently knew the same thing under the name Saccharum; and the author of the Periplus of the Erythrean Sea, a.d. 54-68, states that honey from canes, called σάκχαρι, is exported from Barygaza, in the Gulf of Cambay, to the ports of the Red Sea, west of the Promontorium Aromatum, that is to say to the coast opposite Aden. Whether at that period sugar was produced in Western India, or was brought thither from the Ganges, is a point still doubtful.

Bengal is probably the country of the earliest manufacture of sugar; hence its names in all the languages of Western-Asiatic and European nations are derived from the Sanskrit Sharkarā, signifying a substance in the shape of small grains or stones. It is strange that this word contains no allusion to the taste of the substance.

Candy, as sugar in large crystals is called, is derived from the Arabic Kand or Kandat, a name of the same signification. An old Sanskrit name of Central Bengal is Gura, whence is derived the word Gula, meaning raw sugar, a term for sugar universally employed in the Malayan Archipelago, where on the other hand they have their own names for the sugar cane, although not for sugar. This fact again speaks in favour of Ritter’s opinion, that the preparation of sugar in a dry crystalline state is due to the inhabitants of Bengal. Sugar under the name of Shi-mi, i.e. Stone-honey, is frequently mentioned in the ancient Chinese annals among the productions of India and Persia; and it is recorded that the Emperor Tai-tsung, a.d. 627-650, sent an envoy to the kingdom of Magadha in India, the modern Bahar, to learn the method of manufacturing sugar.[2664] The Chinese, in fact, acknowledge that the Indians between a.d. 766 and 780 were their first teachers in the art of refining sugar, for which they had no particular ancient written character.

An Arabian writer, Abu Zayd al Hasan,[2665] informs us that about a.d. 850 the sugar cane was growing on the north-eastern shore of the Persian Gulf; and in the following century, the traveller Ali Istakhri[2666] found sugar abundantly produced in the Persian province of Kuzistan, the ancient Susiana. About the same time (a.d. 950), Moses of Chorene, an Armenian, also stated that the manufacture of sugar was flourishing near the celebrated school of medicine at Jondisabur in the same province, and remains of this industry in the shape of millstones, &c., still exist near Ahwas.

Persian physicians of the 10th and 11th centuries, as Rhazes, Haly Abbas, and Avicenna, introduced sugar into medicine. The Arabs cultivated the sugar cane in many of their Mediterranean settlements, as Cyprus, Sicily, Italy, Northern Africa, and Spain. The Calendar of Cordova[2667] shows that as early as a.d. 961 the cultivation was well understood in Spain, which is now the only country in Europe where sugar mills still exist.[2668]

William II., King of Sicily, presented in a.d. 1176 to the convent of Monreale mills for grinding cane, the culture of which still lingers at Avola near Syracuse, though only for the sake of making rum. In 1767, the sugar plantations and sugar houses at this spot were described by a traveller[2669] as “worth seeing.”

During the middle ages England, in common with the rest of Northern Europe, was supplied with sugar from the Mediterranean countries, especially Egypt and Cyprus. It was imported from Alexandria as early as the end of the 10th century by the Venetians, with whom it long remained an important article of trade. Thus we find[2670] that in a.d. 1319, a merchant in Venice, Tommaso Loredano, shipped to London 100,000 lb. of sugar, the proceeds of which were to be returned in wool, which at that period constituted the great wealth of England. Sugar was then very dear: thus from 1259 to 1350, the average price in England was about 1s. per lb., and from 1351 to 1400, 1s. 7d.[2671] In France during the same period it must have been largely obtainable, though doubtless expensive. King John II. ordered in 1353 that the apothecaries of Paris should not use honey in making those confections which ought to be prepared with the good white sugar called cafetin,[2672] a name alluding to the peculiar shape of the loaf which was not uncommon at that time.[2673]

The importance of the sugar manufacture in the East was witnessed in the latter half of the 13th century by Marco Polo;[2674] and in 1510 by Barbosa and other European travellers; and the trading nations of Europe rapidly spread the cultivation of the cane over all the countries, of which the climate was suitable. Thus its introduction into Madeira goes back as far as a.d. 1420; it reached St. Domingo in 1494,[2675] the Canary Islands in 1503, Brazil in the beginning of the 16th century, Mexico about 1520, Guiana about 1600, Guadaloupe in 1644, Martinique in 1650,[2676] Mauritius towards 1750, Natal[2677] and New South Wales, about 1852,[2678] while from a very early period the sugar cane had been propagated from the Indian Archipelago over all the islands of the Pacific Ocean.

The ancient cultivation in Egypt, probably never quite extinct, has been revived on an extensive scale by the Khedive Ismail Pasha. There were 13 sugar factories, making raw sugar, belonging to the Egyptian Government at work in 1872, and about 100,000 acres of land devoted to sugar cane. The export of sugar from Egypt in 1872 reached 2 millions of kantars, or about 89,200 tons.[2679]

The imperfection of organic chemistry previous to the middle of the 18th century, permitted no exact investigations into the chemical nature of sugar. Marggraf of Berlin[2680] proved in 1747 that sugar occurs in many vegetables, and succeeded in obtaining it in a pure crystallized state from the juice of beet root. The enormous practical importance of this discovery did not escape him, and he caused serious attempts to be made for rendering it available, which were so far successful that the first manufactory of beet-sugar was established in 1796 by Achard at Kunern in Silesia.

This new branch of industry[2681] was greatly promoted by the prohibitive measures, whereby Napoleon excluded colonial sugar from almost the whole Continent; and it is now carried forward on such a scale that 640,000 to 680,000 tons of beet root sugar are annually produced in Europe, the entire production of cane-sugar being estimated at 1,260,000 to 1,413,000 tons.[2682]

Among the British colonies, Mauritius,[2683] British Guiana,[2684] Trinidad,[2685] Barbados,[2686] and Jamaica,[2687] produce at present the largest quantity of sugar.

Production—No crystals are found in the parenchyme of the cane, the sugar existing as an aqueous solution, chiefly within the cells of the centre of the stem. The transverse section of the cane exhibits numerous fibro-vascular bundles, scattered through the tissue, as in other monocotyledonous stems; yet these bundles are most abundant towards the exterior, where they form a dense ring covered with a thin epidermis, which is very hard by reason of the silica which is deposited in it.[2688] In the centre of the stem the vascular bundles are few in number; the parenchyme is far more abundant, and contains in its thin-walled cells an almost clear solution of sugar, with a few small starch granules and a little soluble albuminous matter. This last is met with in larger quantity in the cambial portion of the vascular bundles. Pectic principles are combined with the walls of the medullary cells, which however do not swell much in water (Wiesner).

From these glances at the microscopical structure of the cane, the process to be followed for obtaining the largest possible quantity of sugar becomes evident. This would consist in simply macerating thin slices of the cane in water, which would at once penetrate the parenchyme loaded with sugar, without much attacking the fibro-vascular bundles containing more of albuminous than of saccharine matter. By this method, the epidermal layer of the cane would not become saturated with sugar, nor would it impede its extraction,—results which necessarily follow when the cane is crushed and pressed.[2689]

The process hitherto generally practised in the colonies,—that of extracting the juice of the cane by crushing and pressing,—has been elaborately described and criticised by Dr. Icery of Mauritius.[2690] In that island, the cane, six varieties of which are cultivated, is when mature composed of Cellulose, 8 to 12 per cent.; Sugar, 18 to 21; Water, including albuminous matter and salts, 67 to 73. Of the entire quantity of juice in the cane, from 70 to 84 per cent. is extracted for evaporation, and yields in a crystalline state about three-fifths of the sugar which the cane originally contained. This juice, called in French vesou, has on an average the following composition:—

There is also present in the juice a very small amount of a slightly aromatic substance (essential oil?) to which the crude cane sugar owes a peculiar odour which is not observed in sugar from other sources. The first two classes of the above enumerated substances render the juice turbid, and greatly promote its fermentation, but they easily separate by boiling, and the juice may then be kept a short time without undergoing change. In many colonies the yield is said to be far inferior to what it should be; yet the juice is obtained in a state allowing of easier purification, when its extraction is not carried to the furthest limit.

In beet root as well as in the sugar cane, cane-sugar only was said to be present; Icery however has proved that in the cane some uncrystallizable (inverted) sugar is always present. Its quantity varies much, according to the places where the cane grows, and its age. The tops of quick-growing young canes yielded a vesou containing 2·4 per cent. of uncrystallizable sugar; 3·6 of cane sugar; and 94 of water. Moist and shady situations greatly promote the formation of the former kind of sugar, which also prevails in the tops, chiefly when immature. Hence that observer concludes that at first the uncrystallizable variety of sugar is formed, and subsequently transformed into cane-sugar by the force of vegetation, and especially by the influence of light. Perfectly ripened canes contain only ¹/₇₅ to ¹/₅₀ of all their sugar in the uncrystallizable state.

Description and Chemical Composition—Cane-sugar is the type of a numerous class of well-defined organic compounds, of frequent occurrence throughout the vegetable and animal kingdoms, or artificially obtained by decomposing certain other substances; in the latter case, however, glucose or some other sugar than cane-sugar is obtained. cane-sugar, C₁₂H₂₂O₁₁, or C₁₂H₁₄(OH)₈O₃, melts, without change of composition, at 160° C., several other kinds of sugar giving off water, with which they form crystallized compounds at the ordinary temperature.

cane-sugar forms hard crystals of the oblique rhombic system, having a sp. gr. of 1·59. Two parts are dissolved at 15° C. by one part of water,[2692] and by much less at an elevated temperature; a slight depression of the thermometer is observable in the former case. One part of sugar dissolved in one of water, forms a liquid of sp. gr. 1·23; two of sugar in one of water, a liquid of sp. gr. 1·33. Sugar requires 65 parts of spirit of wine (sp. gr. 0·84) or 80 parts of anhydrous alcohol for solution; ether does not act upon it.

A ray of polarized light is deviated by an aqueous solution of cane sugar to the right, but by some other kinds of sugar to the left, as first shown by Biot. These optical powers are highly important, both in the practical estimation of solutions of sugar, and in scientific studies connected with sugar or saccharogenous substances. The optical as well as chemical properties of sugar are altered by many circumstances, as the action of dilute acids or alkalis, or by the influence of minute fungi. Yeast occasions sugar to undergo alcoholic fermentation. Other ferments set up an action by which butyric, lactic or propionic acid are produced.

cane-sugar is of a purer and sweeter taste than most other sugars. Though it does not alter litmus paper, yet with alkalis it forms compounds some of which are crystallizable. From an alkaline solution of tartrate of copper, cane-sugar throws down no protoxide, unless after boiling.

If sugar is kept a short time in a state of fusion at 160° C., it is converted into one molecule of Grape Sugar and one of Levulosan; the former can be either isolated by crystallization or destroyed by fermentation, the latter being incapable of crystallizing or of undergoing fermentation.

cane-sugar which has been melted at 160° C. is deliquescent and readily soluble in anhydrous alcohol, and its rotatory power is diminished or entirely destroyed. It is no longer crystallizable, and its fusing point has become reduced to about 93° C. Yet before undergoing these evident alterations, it assumes an amorphous condition if allowed to melt with a third of its weight of water, becoming always a little coloured by pyrogenous products. In the course of time, however, this amorphous sugar loses its transparency and reassumes the crystalline form. Like sulphur and arsenious acid, it is capable of existing either in a crystallized or an amorphous state.

If sugar is heated to about 190° C. water is evolved, and we obtain the dark brown products commonly called Caramel or Burnt Sugar. They are of a peculiar sharp flavour, of a bitter taste, incapable of fermenting and deliquescent. One of the constituents of caramel, Caramelane, C₁₂H₁₈O₉, has been obtained by Gélis (1862) perfectly colourless. When the heat is augmented, the sugar at last suffers a decomposition resembling that which produces tar (see p. 621), its pyrogenous products being the same or very analogous to those of the dry distillation of wood.

Varieties of Cane-sugar—The experiments of Marggraf referred to at p. 717, note 9, showed that cane-sugar is by no means confined to the sugar cane; and it is in fact extracted on an extensive scale from several other plants, of which the following deserve mention:—

Beet Root—The manufacture of cane-sugar from the fleshy root of a cultivated variety of Beta maritima L., is now largely carried on in Continental Europe and in America, and with admirable results.

Of fresh beet root, 100 parts contain on an average 80 per cent. of water, 11 to 13 of cane-sugar, and about 7 per cent. of pectic and albuminous matters, cellulose and salts. Of the total amount of juice which the root contains, eight-ninths are extracted; and by the best process now in practice, 8 to 9 parts of sugar from every 100 parts of fresh root. The yield of crystalline sugar is still on the increase, owing to continual improvements in the mechanical and chemical parts of the process.

Palm—Several species are of great utility for the production of the sugar called by Europeans Jaggery.[2693] This substance is obtained by the natives of India in the following manner:—The young growing spadix, or flowering shoot, of the palm is cut off near its apex; and an earthen vessel is tied on to the stump to receive the juice that flows out. This vessel is emptied daily; while to promote a continuous flow of sap, a thin slice is cut from the wounded end. The juice thus collected, if at once boiled down, yields the crude brown sugar known as jaggery. If allowed to ferment, it becomes the inebriating drink called Toddy or palm wine; or it may be converted into vinegar. The spirit distilled from toddy is Arrack.

Of the sugar-yielding palms of Asia, Phœnix silvestris Roxb., which is supposed to be the wild form of the date palm, is one of the more important. The coco-nut palm, Cocos nucifera L.; the magnificent Palmyra palm, Borassua flabelliformis L.; and the Bastard Sago, Caryota urens L., also furnish important quantities of sugar. In the Indian Archipelago, sugar is obtained from the sap of Arenga saccharifera Mart., which grows there in abundance as well as in the Philippines and the Indo-Chinese countries. It is also got from Nipa fruticans Thunb., a tree of the low coast regions, extensively cultivated in Tavoy.

De Vry[2694] has advocated the manufacture of sugar from the palm as the most philosophical, seeing that its juice is a nearly pure aqueous solution of sugar: that as no mineral constituents are removed from the soil in this juice, the costly manuring, as well as the laborious and destructive processes required to eliminate the juice from such plants as the sugar cane and beet root, are avoided. And finally, that palms are perennial, and can many of them be cultivated on a soil unsuitable for any cereal.

Maple—In America, considerable quantities of sugar identical with that of the cane are obtained in the woods of the Northern United States and of Canada, by evaporating the juice of maples. The species chiefly employed are Acer saccharinum Wangenh., the Common Sugar Maple, and its variety (var. nigrum) the Black Sugar Maple. A. Pennsylvanicum L., A. Negundo L. (Negundo aceroides Moench.) and A. dasycarpum Ehrh. are also used; the sap of the last is said to be the least saccharine.

As the juice of these trees yields not more than about 2 per cent. of sugar, it requires for its solidification a large expenditure of fuel. The manufacture of maple sugar can therefore be advantageously carried on only in countries remote from markets whence ordinary sugar can be procured, or in regions where fuel is extremely plentiful. In North America it flourishes only between 40° and 43° N. lat. We are not aware of any estimate of the total production of maple sugar. The Census of Pennsylvania of 1870 gave the following figures as referring to its manufacture in that State:—

Sorghum—Another plant of the same order as Saccharum is Sorghum saccharatum Pers. (Holcus saccharatus L.) a native of Northern China,[2696] which has of late been much tried as a sugar-yielding plant both in Europe and North America; yet without any great success, as the purification of the sugar is accomplished with peculiar difficulty. As in the sugar cane, there are in sorghum crystallizable and uncrystallizable sugars, the former being at its maximum amount when the grain reaches maturity. The importance of the plant however is rapidly increasing on account of the value of its leaves and grain as food for horses and cattle, and of its stems which can be employed in the manufacture of paper and of alcohol.

Commerce—The value of the sugar imported into the United Kingdom is constantly increasing, as shown by the following figures:—

The quantity of Unrefined Sugar imported in 1872 was 13,776,696 cwt., of which about 3,000,000 cwt. were furnished by the Spanish West India Islands, 2,700,000 cwt. by the British West India Islands, 1,800,000 cwt. by Brazil, 1,100,000 cwt. by France, and 960,000 cwt. by Mauritius.

Of Refined Sugar the imports from France and Belgium into the United Kingdom were—

Uses—Refined sugar is employed in pharmacy for making syrups, electuaries and lozenges, and is useful not merely for the sake of covering the unpleasant taste of other drugs, but also on account of a preservative influence which it exerts over their active constituents.

Muscovado or Raw Sugar is not used in medicine. The dark uncrystallizable syrup, known in England as Molasses, Golden Syrup, and Treacle,[2697] and in foreign pharmacy as Syrupus Hollandicus vel communis, which is formed in the preparation of pure sugar by the influence of heat, alkaline bodies, microscopic vegetation, and the oxygen of the air, is sometimes employed for making pill masses. The treacle of colonial sugar alone is adapted for this purpose, that of beet root having a disagreeable taste, and containing from 19 to 21 per cent. of oxalate, tartrate and malate of potassium, and only 56 to 64 of sugar.[2698] The treacle of colonial sugar usually contains 5 to 7 per cent. of salts.

HORDEUM DECORTICATUM.

Botanical Origin—Hordeum distichum L.,—the Common or Long-eared Barley is probably indigenous to western temperate Asia, but has been cultivated for ages throughout the northern hemisphere. In Sweden its cultivation extends as far as 68° 38’ N. lat.; on the Norwegian coast up to the Altenfjord in 70° N. lat.; even in Lapland, it succeeds as high as 900 to 1350 feet above the level of the sea. In several of the southern Swiss Alpine valleys, barley ripens at 5000 feet, and in the Himalaya at 11,000 feet. In the Equatorial Andes, where it is extensively grown, it thrives up to at least 11,000 feet above the sea. No other cereal can be cultivated under so great a variety of climate.

According to Bretschneider,[2699] barley is included among the five cereals which it is related in Chinese history were sowed by the Emperor Shen-nung, who reigned about 2700 b.c.; but it is not one of the five sorts of grain which are used at the ceremony of ploughing and sowing as now annually performed by the emperors of China.

Theophrastus was acquainted with several sorts of barley (Κριθή), and among them, with the six-rowed kind or hexastichon, which is the species that is represented on the coins struck at Metapontum[2700] in Lucania, between the 6th and 2nd centuries b.c.

Strabo and Dioscorides in the 1st century allude to drinks made from barley, which according to Tacitus were even then familiar to the German tribes, as they are known to have been still earlier to the Greeks and Egyptians.

Barley is mentioned in the Bible as a plant of cultivation in Egypt and Syria, and must have been, among the ancient Hebrews, an important article of food, judging from the quantity allowed by Solomon to the servants of Hiram, king of Tyre (b.c. 1015). The tribute of barley paid to King Jotham by the Ammonites (b.c. 741) is also exactly recorded. The ancients were frequently in the practice of removing the hard integuments of barley by roasting it, and using the torrefied grain as food.

Manufacture—For use in medicine and as food for the sick, barley is not employed in its crude state, but only when deprived more or less completely of its husk. The process by which this is effected is carried on in mills constructed for the purpose, and consists essentially in passing the grain between horizontal millstones, placed so far apart as to rub off its integuments without crushing it. Barley partially deprived of its husk is known as Scotch, hulled or Pot Barley. When by longer and closer grinding the whole of the integuments have been removed, and the grain has become completely rounded, it is termed Pearl Barley. In the British Pharmacopœia it is this sort alone which is ordered to be used.

Description—Pearl Barley is in subspherical or somewhat ovoid grains about 2 lines in diameter, of white farinaceous aspect, often partly yellowish from remains of the adhering husk, which is present on the surface, as well as in the deep longitudinal furrow with which each grain is indented. It has the farinaceous taste and odour which are common to most of the cereal grains.

Microscopic Structure—The albumen which constitutes the main portion of the grain is composed of large thin-walled parenchyme, the cells of which on transverse section are seen to radiate from the furrow, and to be lengthened in that direction rather than longitudinally. In the vicinity of the furrow alone the tissue of the albumen is narrower. Its predominating large cells show a polygonal or oval outline, whilst the outer layer is built up of two, three or four rows of thick-walled, coherent, nearly cubic gluten-cells. This layer, about 70 mkm. thick, is coated with an extremely thin brown tegument, to which succeeds a layer about 30 mkm. thick, of densely packed, tabular, greyish or yellowish cells of very small size; this proper coat of the fruit in the furrow is of rather spongy appearance.

In some varieties of barley the fruit is constituted of the above tissues alone and the shell, but in most the paleæ are likewise present. They consist chiefly of long fibrous, thick-walled cells, two or four rows deep, constituting a very hard layer. On tranverse section, this layer forms a coherent envelope about 35 mkm. thick; its cells when examined in longitudinal section show but a small lumen of peculiar undulated outline from secondary deposits.

The gluten-cells varying considerably in the different cereal grains, afford characters enough to distinguish them with certainty. In wheat, for instance, the gluten-cells are in a single row, in rice they form a double or single row, but its cells are transversely lengthened.

The inner tissue of the albumen in barley is filled up with large irregularly lenticular, and with extremely small globular starch granules, the first being 20 to 35 mkm., the latter 1, 2 to 3 mkm. in diameter, with no considerable number of intermediate size. The concentric layers constituting the large granules may be made conspicuous by moistening with chromic acid.

The layer alluded to as being composed of gluten-cells is loaded with extremely small granules of albuminous matters (gluten), which on addition of iodine are coloured intensely yellow. These granules, which, considering barley as an article of food, are of prominent value, are not confined to the gluten-cells, but the neighbouring starch-cells also contain a small amount of them: and in the narrow zone of denser tissue projecting from the furrow into the albumen, protein principles are equally deposited, as shown by the yellow coloration which iodine produces.

The gluten-cells, the membrane embroynnaire of Mège-Mouriès, contain also, according to the researches on bread[2701] made by this chemist (1856), Cerealin, an albuminous principle soluble in water, which causes the transformation of starch into dextrin, sugar, and lactic acid. In the husks (épiderme, épicarpe and endocarpe) of wheat, Mège-Mouriès found some volatile oil and a yellow extractive matter, to which, together with the cerealin, is due the acidity of bread made with the flour containing the bran.

Chemical Composition—Barley has been submitted to careful analyses by many chemists, more especially by Lermer.[2702] The grains contain usually 13 to 15 per cent. of water; after drying, they yield to ether 3 per cent. of fat oil, with insignificant proportions of tannic and bitter principles, residing chiefly in the husks. Lermer further found in the whole grains, 63 per cent. of starch, 7 of cellulose, 6·6 of dextrin, 2·5 of nitrogen, a small amount of lactic acid, and 2·4 of ash.

The analysis of Poggiale (1856) gave nearly the same composition, namely, water 15, oil 2·4, starch 60, cellulose 8·8, albuminous principles 10·7, ash 2·6.

The protein, or albuminous matter consists of different principles, chiefly insoluble in cold water. The soluble portion is partly coagulated on boiling, partly retained in solution: 2·5 per cent. of nitrogen, as above, would answer to about 16 per cent. of albuminous matters. Their soluble part seems to be deposited in the starch-cells, next to the gluten-cells, which latter contain the insoluble portion.

The ash, according to Lermer, contains 29 per cent. of silicic acid, 32·6 of phosphoric acid, 22·7 of potash, and only 3·7 of lime. In the opinion of Salm-Horstmar, fluorine and lithia are indispensable constituents of barley.

The fixed oil of barley, as proved in 1863 by Hanamann, is a compound of glycerin with either a mixture of palmitic and lauric acids, or less probably with a peculiar fatty acid. Beckmann’s Hordeinic Acid obtained in 1855 by distilling barley with sulphuric acid, is probably lauric acid. Lintner (1868) has shown barley to contain also a little Cholesterin (p. 420).

Lastly, Kühnemann (1875) extracted from barley a crystallized dextrogyrate sugar, and (1876) an amorphous lævogyrate mucilaginous substance Sinistrin (see p. 692); according to that chemist, dextrin is altogether wanting in barley.

Barley when malted loses 7 per cent.; it then contains 10 to 12 per cent. of sugar, produced at the expense of the starch; before malting, no sugar is to be found.

Uses—Barley as a medicine is unimportant. A decoction is sometimes prescribed as a demulcent or as a diluent of active remedies. An aqueous extract of malt has been employed.

OLEUM ANDROPOGONIS.

Oleum Graminis Indici; Indian Grass Oil.

Botanical Origin—Among the numerous species of Andropogon[2703] which have foliage abounding in essential oil, the following furnish the fragrant Grass Oils of commerce:—

1. Andropogon Nardus L.,[2704]—a noble-looking plant, rising when in flower to a height of 6 or more feet, extensively cultivated in Ceylon and Singapore for the production of Citronella Oil.

2. A. citratus D.C.,[2705] Lemon Grass,—a large coarse glaucous grass, known only in a cultivated state, and very rarely producing flowers. It is grown in Ceylon and Singapore for the sake of its essential oil, which is called Lemon Grass Oil, Oil of Verbena or Indian Melissa Oil; it is also commonly met with in gardens throughout India and is not unfrequent in English hothouses. In Java it is called Sireh.

3. A. Schœnanthus L.,[2706] a grass of Northern and Central India, having leaves rounded or slightly cordate at the base, yielding by distillation the oil known as Rúsa Oil, Oil of Ginger Grass or of Geranium.

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.

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:—

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:—

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 2s.).

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]

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]

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.