part 18

(1877).

[1470] As we learn from Dr. Rice.—Prof. Dymock (1876) gives _Timbooree_ as the Bombay name.

[1471] Tom. iii. tab. 41.

[1472] _Bengal Dispensatory_, Calcutta, 1842. 428.

[1473] _Etude sur le Plaqueminier_ (_Diospyros_), thèse, Paris, 1873. 28-30.

STYRACEÆ.

RESINA BENZOË.

_Benzoïnum_; _Benzoin_, _Gum Benjamin_; F. _Benjoin_; G. _Benzoëharz_.[1474]

=Botanical Origin=—_Styrax Benzoin_ Dryander, a tree of moderate height, with stem as thick as a man’s body and beautiful crown of foliage, indigenous to Sumatra and Java, in the first of which islands benzoin is produced.

[1474] _Benzoin_ in Malay and Javanese is termed _Kamâñan_, _Kamiñan_, and _Kamayan_, abbreviated to _mâñan_ and _miñan_ (Crawfurd); it is called in Siamese _kom-yan_ or _kan-yan_; in Chinese _ngán-si-hiáng_.

The name _Benzoin_ is also applied to the beautiful prisms C₁₄H₁₂O₂ obtained by treating Bitter Almond Oil with an alcoholic solution of potash.

The tree yielding the superior benzoin of Siam, though commonly referred to this species, has never been examined botanically, and is actually unknown. The French expedition for the exploration of the Mekong and Cochin China (1866-68), reported the drug to be produced in the cassia-yielding forests on the eastern bank of the river in question in about N. lat. 19°. Whether any benzoin is obtained from _S. Finlaysoniana_ Wall, as conjectured by Royle, we know not.

=History=—There is no evidence that the Greeks and Romans,[1475] or even the earlier Arabian physicians, had any acquaintance with benzoin; nor is the drug to be recognized among the commodities which were conveyed to China by the Arab and Persian traders between the 10th and 13th centuries, though the camphor of Sumatra is expressly named.

The first mention of benzoin known to us (disregarding the word kalanusari, which in the St. Petersburg Dictionary is given as the old Sanskrit name of benzoin) occurs in the travels of Ibn Batuta,[1476] who having visited Sumatra during his journey through the East, A.D. 1325-49, notes that the island produces _Java Frankincense_ and camphor. The word _Java_ was at that period a designation of Sumatra, or was even used by the Arabs to signify the islands and productions of the Archipelago generally.[1477] Hence came the Arabic name _Lubán Jáwí_, i.e. _Java Frankincense_, corrupted into _Banjawi_, _Benjui_, _Benzui_, _Benzoë_ and _Benzoïn_, and into the still more vulgar English _Benjamin_.

We have no further information about the drug until the latter half of the following century, when we find a record that in 1461 the sultan of Egypt, Melech Elmaydi, sent to Pasquale Malipiero, doge of Venice, a present of 30 _rotoli_ of _Benzoi_, 20 _rotoli_ of Aloes Wood, two pairs of Carpets, a small flask of balsam (of Mecca), 15 little boxes of Theriaka, 42 loaves of Sugar, 5 boxes of Sugar Candy, a horn of Civet, and 20 pieces of Porcelain.[1478] Agostino Barberigo, another doge of Venice, was presented in a similar manner in 1490 by the sultan of Egypt with 35 _rotoli_ of Aloes Wood, the same quantity of _Benzui_ and 100 loaves of Sugar.[1479]

Among the precious spices sent from Egypt in 1476 to Caterina Cornaro, queen of Cyprus, were 10 lb. of Aloes Wood and 15 lb. of _Benzui_.[1480] These notices indicate the high value set upon the drug when first brought to Europe.

The occurrence of benzoin in Siam is noticed in the journal of the voyage of Vasco da Gama,[1481] where, in enumerating the kingdoms of India, it is stated that Xarnaux (Siam[1482]) yields much benzoin worth 3 _cruzados_, and aloes worth 25 _cruzados_ per _farazola_. According to the same record, the price of benzoin (_beijoim_) in Alexandria was 1 _cruzado_ per _arratel_, half the value of aloes wood.

[1475] Crawfurd suggests that the _Malabathrum_ of the ancients is possibly _benzoin_.—_Dict. of Indian Islands_, 1856. 50.

[1476] _Voyages d’Ibn Batoutah_, traduit par Defrémery et Sanguinetti, Paris, 1853-59. iv. 228. 240.

[1477] Yule, _Book of Ser Marco Polo_, ii. (1871) 228.

[1478] Muratori, _Rerum Italicarum Scriptores_, xxii. (1733) 1170.—100 _rotoli_ = 175 lb. avoirdupois.

[1479] L. de Mas Latrie, _Hist. de l’île de Chypre_, etc. iii. (1861) 483.

[1480] _Ibid._ iii. 406.

[1481] _Roteiro da Viagem de Vasco da Gama em 1497_, par Herculano e o Barão Castello de Paiva, segunda edição, Lisboa, 1861. 109.

The Roteiro is also found in Flückiger, _Documente zur Geschichte der Pharmacie_, Halle, 1876. 13.

[1482] Yule, _op. cit._ ii. 222.

The Portuguese traveller Barbosa[1483] visited in 1511 Calicut on the Malabar Coast, and found _Benzui_ to be one of the more valuable items of export, one _farazola_ (22 lb. 6 oz.) costing 65 to 70 _fanoes_; camphor fetched nearly the same price, and mace only 25 to 30 _fanoes_. From other sources we gather that benzoin was an article of Venetian trade in the beginning of the 16th century.

Garcia de Orta, writing at Goa (1563), was the first to give a lucid and intelligent account of benzoin, detailing the method of collection, and distinguishing the drug of Siam and Martaban from that produced in Java and Sumatra.

It began then to be regularly imported into Europe,[1484] being frequently called _Asa dulcis_. The chemists of that time submitted it, like many other substances, to dry distillation. Benzoic acid occasionally separating from the oily products (“_oleum Benzoës_”) was noticed already by Nostredame,[1485] Rosello,[1486] Liebaut,[1487] Blaise de Vigenère,[1488] and others. It was a common pharmaceutical preparation, under the name of _Flores Benzoës_, since the 17th century.[1489]

In the early part of the 17th century, there was direct commercial intercourse between England and both Siam and Sumatra, an English factory existing at Ayuthia (Siam) until 1623; and benzoin was doubtless one of the commodities imported. The import duties levied upon it in England in 1635 amounted to 10_s._ per lb.[1490]

=Production=—Benzoin is collected in Northern and Eastern Sumatra, especially in the Batta country, lying southward of the state of Achin.[1491] The tree grows in plenty also in the highlands of Palembang in the south and its resin is collected. It is chiefly on the coast regions that considerable plantations are found. Teysmann saw the cultivation in the tracts of the river Batang Leko, the trees being planted about 15 feet apart. The benzoin from the interior is mostly from wild trees, which occur at the foot of the mountains at an elevation of 300 to 1000 feet.

The trees, which are of quick growth, are raised from seeds grown on the [edges of?] rice-fields; they require no particular attention beyond being kept clear of other plants, until about 6 or 7 years old, when they have trunks 6 to 8 inches in diameter, and are capable of yielding the resin. Incisions are then made in their stems, from which there exudes a thick, whitish, resinous juice, which soon hardens by exposure to the air, and is carefully scraped off with a knife.

[1483] Flückiger, _l.c._, page 14.

[1484] Cardanus, _Les livres de la subtilité_, Paris, 1556 (first edition, 1550), page 160 _b._ states: “belzoi est de vil prix pour l’abondance.”

[1485] _Excellent et moult utile opuscule à touts necessaire qui desirent avoir cognoissance de plusieurs exquises receptes_, 1556.

[1486] Alexii Pedemontani (or Hieron. Rosello), _De secretis libri vi._, Basil, 1560, page 107.

[1487] _Quatre livres de secrets de medecine et de la philosophie chimique_, Paris, 1579, page 146.

[1488] _Traicté du feu et du sel_, Paris, 1622, page 99.—Vigenère speaks distinctly of “filamens ou aiguilles,” i.e. crystals.—He died in 1596.

[1489] Flückiger, _Pharm. Journ._ vi. (1876) 1022.

[1490] _The Rates of Marchandizes_, London, 1635.

[1491] Miquel, _Prodromus Floræ Sumatranæ_, 1860. 72; Marsden, _Hist. of Sumatra_, London, 1783. 123.—The latter author resided at Bencoolen, as an official of the English Government.

The statement of Crawfurd, _l.c._, that benzoin is collected in Borneo “_on the northern coast in the territory of Brunai_” is to us inexplicable. Mr. St. John, British Consul in Borneo, in an official report on the trade of Brunai, dated from that place 29 January 1858, enumerates the various productions of the district, but does not name benzoin.

The trees continue to yield at the rate of about three pounds per annum for 10 or 12 years, after which period they are cut down. The resin which exudes during the first three years is said to be fuller of white tears, and therefore of finer quality, than that which issues subsequently, and is termed by the Malays _Head Benzoin_. That which flows during the next 7 or 8 years, is browner in colour and less valuable, and is known as _Belly Benzoin_; while a third sort, called _Foot_, is obtained by splitting the tree and scraping the wood; this last is mixed with much bark and refuse.[1492]

Benzoin is brought for sale to the ports of Sumatra in large cakes called _Tampangs_, wrapped in matting. These have to be broken, and softened either by the heat of the sun or by that of boiling water, and then packed into square cases which the resin is made to fill.

The only account of the collection of _Siam Benzoin_ is that given by Sir R. H. Schomburgk, for some years British Consul at Bangkok.[1493] He represents that the bark is gashed all over, and that the resin which exudes, collects and hardens between it and the wood, the former of which is then stripped off. This account is confirmed by the aspect of some of the Siam benzoin of commerce as well as by that of pieces of bark in our possession; but it is also evident that _all_ the Siam drug is not thus obtained. Schomburgk adds, that the resin is much injured and broken during its conveyance in small baskets on bullocks’ backs to the navigable parts of the Menam, whence it is brought down to Bangkok.[1494]

Whether benzoin owes its original fluidity to a volatile oil holding the resin in solution, and its solidification to the volatilization of this oil, or whether the resin itself hardens by oxidation,—what occasions the remarkable diversity of aspect between the opaque and milk-like, and the completely transparent resin, are questions to be investigated by some future observer.

=Description=—Benzoin (always termed in English commerce _Gum Benjamin_) is distinguished as of two kinds, _Siam_ and _Sumatra_. Each sort occurs in various degrees of purity, and under considerable differences of appearance.

1. _Siam Benzoin_—The most esteemed sort is that which consists entirely of flattened tears or drops, an inch or two long, of an opaque, milk-like, white resin, loosely agglutinated into a mass. More frequently the mass is quite compact, consisting of a certain proportion of white tears of the size of an almond downwards, imbedded in a deep, rich amber-brown, translucent resin. Occasionally the translucent resin preponderates, and the white tears are almost wanting. In some packages, the tears of white resin are very small, and the whole mass has the aspect of a reddish-brown granite. There is always a certain admixture of bits of wood, bark, and other accidental impurities.

[1492] The terms _Head_, _Belly_ and _Foot_, equivalent to our words _superior_, _medium_ and _inferior_, are used in the East to distinguish the qualities of many other commodities, as Borneo Camphor, Esculent Birds’-nests, Cardamoms, Galbanum, &c.

[1493] This account must have been derived from others, for Sir R. H. Schomburgk never visited the region producing benzoin.

[1494] _Pharm. Journ._ iii. (1862) 126.

The white tears when broken, display a stratified structure with layers of greater or less translucency. By keeping, the white milky resin becomes brown and transparent on the surface.

Siam benzoin is very brittle, the opaque tears showing a slightly waxy, the transparent a glassy fracture. It easily softens in the mouth and may be kneaded with the teeth like mastich. It has a delicate balsamic, vanilla-like, fragrance, but very little taste. When heated it evolves a more powerful fragrance, together with the irritating fumes of benzoic acid; its fusing point is 75° C. The presence of benzoic acid may be shown by the microscopical examination of splinters of the resin under oil of turpentine.

Siam benzoin is imported in cubic blocks, which takes their form from the wooden cases in which they are packed while the resin is still soft.

2. _Sumatra Benzoin_—Prior to the renewal of direct commercial intercourse with Siam in 1853, this was the sort of benzoin most commonly found in commerce.

It is imported in cubic blocks exactly like the preceding, from which it differs in its generally greyer tint. The mass however, when the drug is of good quality, contains numerous opaque tears, set in a translucent, greyish-brown resin, mixed with bits of wood and bark. When less good, the white tears are wanting, and the proportion of impurities is greater. We have even seen samples consisting almost wholly of bark. In odour, Sumatra benzoin is both weaker and less agreeable than the Siam drug, and generally falls short of it in purity[1495] and handsome appearance, and hence commands a much lower price. The greyish-brown portion melts at 95°, the tears at 85° C.

A variety of Sumatra benzoin is distinguished by the London drug-brokers as _Penang Benjamin_ or _Storax-smelling Benjamin_. We have seen it of very fine quality, full of white tears (some of them two inches long), the intervening resin being greyish.[1496] The odour is very agreeable, and perceptibly different from that of Siam benzoin, or the usual Sumatra sort. Whether this drug is produced in Sumatra and by _Styrax Benzoin_ we know not; but it is worthy of note that _S. subdenticulata_ Miq., occurring in Western Sumatra, has the same native name (_Kajoe Kĕminjan_) as _S. Benzoin_, and that Miquel remarks of it—“_An etiam benzoiferum?_”[1497]

=Chemical Composition=—Benzoin consists mainly of amorphous resins perfectly soluble in alcohol and in potash, having slightly acid properties, and differing in their behaviour to solvents. If two parts of the drug are boiled with one part of caustic lime and 20 parts of water, benzoin acid is removed. From the residue the excess of lime is dissolved by hydrochloric acid, and the remaining resins washed and dried. About one-third of them will be found readily soluble in ether, the prevailing portion dissolves in alcohol, and a small amount remains undissolved.

[1495] In the _Public Ledger_, May 2, 1874, the prices are quoted thus:—Siam Gum Benjamin, 1st and 2nd qualities, £10 to £28 per cwt.; Sumatra, 1st and 2nd, £7 10_s._ to £12.

[1496] There were 8 cases of this drug offered at Public Sale, 13 April 1871.

[1497] _Prod. Floræ Sumatranæ_, 1860. 474.

By distilling the resin of benzoin with ten times its weight of zinc dust, Ciamician (1878) chiefly obtained toluol, C₆H₅(CH₃).

Subjected to dry distillation, benzoin affords as chief product _Benzoic Acid_, C₇H₆O₂, together with empyreumatic products, among which Berthelot has proved the presence (in Siam benzoin) of _Styrol_ (p. 274). The latter has been obtained in 1874 by Theegarten from Sumatra benzoë by distilling it with water. When the resin is fused with potash, it is partly decomposed and then, according to Hlasiwetz and Barth (1866), yields among other products, protocatechuic acid (more than 5 per cent.), C₆H₃(OH)₂COOH, para-oxybenzoic acid, C₆H₄(OH)COOH, and pyrocatechin, C₆H₄(OH)₂.

_Benzoic acid_ exists ready-formed in the drug to the extent of 14 to 18 per cent.[1498] Although the acid dissolves in 12 parts of boiling water, the resin in which it is imbedded precludes its complete extraction by this means. It is however easily accomplished by the aid of an alkali, most advantageously by milk of lime, which does not combine with the amorphous resins.

Benzoin is not manifestly acted on by bisulphide of carbon, but if kept in contact with it for a month or two, very large colourless crystals of benzoic acid make their appearance. Brought into a warm room, the crystals quickly dissolve, but are easily reproduced by exposure to cold.

Most pharmacopœias require not the inodorous acid obtained by a wet process, but that afforded by sublimation, which contains a small amount of fragrant empyreumatic products. The resin, when repeatedly subjected to sublimation, affords as much as 14 per cent. of benzoic acid. It has long been known that the opaque white tears of benzoin are less rich in benzoic acid than the transparent brown resin in which they lie. From the latter, S. W. Brown (1833) extracted 13 per cent. of impure acid, but from the former scarcely 8½ per cent. We are by no means sure that such difference is constant.

Bitter almond oil, which by oxidation yields benzoic acid, is wanting in benzoin. Very little volatile oil is in fact to be got; half a pound of the best Penang benzoin yielded us by distillation with water only a few drops of an extremely fragrant oil (_styrol?_).

Ferric chloride imparts to an alcoholic solution of benzoin a dark brownish green, which is not acquired under the same circumstances by the aqueous decoction of the powdered resin. Benzoin dissolves in cold oil of vitriol, forming a solution of splendid carmine hue, from which water separates crystals of benzoic acid.

Kolbe and Lautemann in 1860 discovered in Siam and Penang benzoin together with benzoic acid, an acid of different constitution, which in 1861 they recognized as _Cinnamic Acid_, C₉H₉O₂. Aschoff (1861) found in a sample of Sumatra benzoin, cinnamic acid only, of which he got 11 per cent.; and in amygdaloid Siam and Penang benzoin only benzoic acid. In some samples of the latter, one of us (F.) has likewise met with cinnamic acid. On triturating this sort with peroxide of lead and boiling the mixture with water, the odour of bitter almond oil, due to the oxidation of cinnamic acid, is evolved.

[1498] Löwe (1870) and Rump (1878) attempted to prove that the acid is

## partly present in the form of a compound, but they have not shown with

which substance it is combined in the drug.

The simultaneous occurrence of benzoic and cinnamic acids, or the absence of one or other of them in benzoin, is due to circumstances at present unexplained. Rump is of the opinion that the last named acid exclusively is present in the Penang (or Sumatra) benzoin and that no variety of the drug contains both those acids.

Rump (1878) treated Siam benzoic with caustic lime (see p. 407), precipitated the benzoic acid with hydrochloric acid, and agitated the liquid with ether. The latter on evaporating afforded a mixture of benzoic acid and _Vanillin_ (see article Vanilla).

=Commerce=—The statistics of Singapore,[1499] the great emporium of the commerce of the Indian Archipelago, show the imports of Gum Benjamin in 1871 as 7442 cwt., of which quantity 6185 cwt. had been shipped from Sumatra and 405 cwt. from Siam. In 1877 only 1871 peculs (2227 cwts.) were exported from Singapore. Penang, which is also a mart for this drug was stated in 1871 to have received from Sumatra for trans-shipment, 4959 cwt. of Gum Benjamin.

Padang in Sumatra exported in 1870, 4303 peculs (5122 cwt.); and in 1871, 4064 peculs (4838 cwt.) of benzoin.[1500]

The imports of Gum Benjamin into Bombay in the year 1871-72 were no less than 5975 cwt., and the exports 1043 cwt.[1501]

=Uses=—Benzoin appears to be nearly devoid of medicinal properties, and is but little employed. It is chiefly imported for use as incense in the service of the Greek Church.

OLEACEÆ.

MANNA.

_Manna_; F. _Manne_; G. _Manna_.

=Botanical Origin=—_Fraxinus Ornus_ L. (_Ornus europæa_ Pers.), the Manna-ash, is a small tree found in Italy, whence it extends northwards as far as the Canton of Tessin in Switzerland and the Southern Tyrol. It also occurs in Hungary (Buda) and the eastern coasts of the Adriatic, in Greece, Turkey (Constantinople), in Asia Minor about Smyrna and at Adalia on the south coast. It grows in the islands of Sicily, Sardinia and Corsica, and is found in Spain at Moxente in Valencia.[1502] As an ornamental tree it has been introduced into Central Europe, where it is often seen of greater dimensions, sometimes acquiring a height of about 30 feet. It blossoms in early summer, producing numerous feathery panicles of dull white flowers which give it a pleasing appearance. The foliage exhibits great variation in shape of leaflets, even where the tree is uncultivated; and the fruits also are very diverse in form.

In some districts of Sicily, a little manna is obtained from the Common Ash, _F. excelsior_ L.

[1499] _Blue Book_ for the Colony of the Straits Settlements, Singapore, 1872.

[1500] _Consular Reports_, August 1873. 953.

[1501] _Statement of the Trade and Navigation of the Presidency of Bombay for 1871-72_, pt. ii. 26. 79.

[1502] _Fraxinus Bungeana_ DC., a tree of Northern China, appears to be hardly distinct from _F. Ornus_.

=History=—The name _Manna_, though originally applied to the aliment miraculously provided for the sustenance of the ancient Israelites during their journey to the Holy Land, has been used to designate other substances of distinct nature and origin. Of these, the best known and most important is the saccharine exudation of _Fraxinus Ornus_ L., which constitutes the _Manna_ of European medicine.

It appears evident[1503] that previous to the 15th century, the manna in Europe was imported from the East and was not that of the ash. Raffaele Maffei, called also Volaterranus, a writer who flourished in the second half of the 15th century, states that manna began to be gathered in Calabria in his time, but that it was inferior to the oriental.[1504] At this period the manna collected was that which exuded spontaneously from the leaves of the tree, and was termed _Manna di foglia_ or _Manna di fronda_: that which flowed from the stem bore the name of _Manna di corpo_ and was less esteemed. All such manna was very dear.

About the middle of the 16th century, the plan of making incisions in the trunk and branches was resorted to, and although it was strenuously opposed even by legislative enactment, the more copious supplies which it enabled the collectors to obtain led it to being generally adopted. The Ricettario Fiorentino of the year 1573[1505] states that the manna “fatta con arte,” _i.e._ obtained by incisions, came from Cosenza in Calabria and differed not little from Syrian “manna mastichina.”[1506]

_Manna di foglia_ became in fact utterly unknown, so that Cirillo of Naples, writing in 1770, expresses doubt whether it ever had any existence.[1507]

With regard to the history of manna-production in Sicily, there is this curious fact, that near Cefalù there exists an eminence in the Madonia range, called _Gebelman_ or _Gibelmanna_, which in Arabic signifies _manna-mountain_. This name is not of modern origin, but is found in a diploma of the year 1082, concerning the foundation of the bishopric of Messina; and it has been held to indicate that manna was there collected during the Saracenic occupation of Sicily, A.D. 827 to 1070. We have not been successful in finding any evidence whether this supposition is well founded. On the other hand, it is remarkable that no writer, so far as we know, mentions manna as a production of Sicily, before Paolo Boccone of Palermo, who, after naming many localities for the drug in continental Italy, states that it is also obtained in Sicily.[1508]

Manna was also produced until recently in the Tuscan Maremma, but neither from that locality, nor from the States of the Church, where it was collected in the time of Boccone, is any supply now brought into commerce, though the name of Tolfa, a town near Civita Vecchia, is still used to designate an inferior sort of the drug.

The collection of manna in Calabria, which was imported up to the end of last century, has now almost entirely ceased.[1509]

[1503] Hanbury, _Historical Notes on Manna_, _Pharm. Journ._ xi. (1870) 326; or _Science Papers_, 355.

[1504] _Commentarii Urbani_, Paris, 1515. lib. 38. f. 413.

[1505] P. 46; we have not seen the edition of 1498.

[1506] Mastichina alludes probably to the granular form of that manna—perhaps it was that of Alhagi, which we shall mention further on, p. 414.

[1507] _Phil. Trans._ lx. (1771) 233.

[1508] _Museo di Fisica_, Venet. 1697. Obs. xiv.-xv.

[1509] Hanbury in _Giornale Botanico Italiano_, Ottobre 1872. 267; _Pharm. Journ._ Nov. 30. 1872. 421; _Science Papers_, 365.

=Production=—The manna of commerce is collected at the present day exclusively in Sicily. The principal localities producing the drug are the districts around Capaci, Carini, Cinisi, and Favarota, small towns 20 to 25 miles west of Palermo near the shores of the bay of Castellamare; also the townships of Geraci, Castelbuono, and other places in the district of Cefalù, 50 to 70 miles eastward of Palermo.

The manna-ash, in the districts whence the best manna is obtained, does not at the present day form natural woods, but is cultivated in regular plantations called _frassinetti_. The trees, which attain a height of from 10 to 20 feet, are planted in rows and stand about 7 feet apart, the soil between being at times loosened, kept free from weeds, and enriched by manure. After a tree is 8 years old and when its stem is at least 3 inches in thickness, the gathering of manna may begin; and may continue for 10 or 12 years, when the stem is usually cut down, and a young one brought up from the same root takes its place. The same stump thus has often two or three stems rising from it.

To obtain manna, transverse cuts from 1½ to 2 inches long and 1 inch apart, are made in the bark, just reaching to the wood. One cut is made daily, beginning at the bottom of the tree, the second directly above the first, and so on while dry weather lasts. In the following year, cuts are made in the untouched part of the stem, and in the same way in succeeding seasons. When after some years the tree has been cut all round and is exhausted, it is felled. Pieces of sticks or straws are inserted in the incisions, and become encrusted with the very superior manna, called _Manna a cannolo_, which however is unknown in commerce as a special sort. The fine manna ordinarily seen appears to have hardened on the stem of the tree. The manna which flows from the lower incisions, and is often collected on tiles or on a cup-shaped piece of the stem of the prickly pear (_Opuntia_), is less crystalline, and more gummy and glutinous, and is regarded of inferior quality.

The best time for notching the stems is in July and August, when the trees have ceased to push forth more leaves. Dry and warm weather is essential for a good harvest. The manna after removal from the tree, is laid upon shelves in order that it may dry and harden before it is packed. The masses left adhering to the stem after the finer pieces have been gathered, are scraped off and form part of the _Small Manna_ of commerce.[1510]

=Secretion=—We have examined microscopically the bark of stems of _Fraxinus Ornus_ that had been incised for manna at Capaci. It exhibits no peculiarity explaining the formation of manna, or any evidence that the saccharine exudation is due to an alteration of the cell-walls as in the case of tragacanth. The bark is poor in tannic matter; it contains starch, and imparts to water a splendid fluorescence due to the presence of _Fraxin_.

[1510] Our account of the production of manna has been derived from the observations of Stettner, who visited Sicily in the summer of 1847 (_Archiv der Pharm._ iii. 194; also Wiggers’ _Jahresbericht_, 1848. 35; _Hooker’s Journ. of Bot._ i. 1849. 124), from those of Cleghorn (_Trans. of the Bot. Soc. of Edinburgh_, x. 1868-69. 132), and from personal investigations made by one of us in the neighbourhood of Palermo in May 1872. See Hanbury, _Science Papers_, 367.

=Description=—Various terms have been used by pharmacological writers to designate the different qualities of manna, but in English commerce they are not now employed; and the better kinds of the drug are called simply _Flake Manna_, while the smaller pieces, usually loosely agglutinated and sold separately, are termed _Small Manna_ or _Tolfa Manna_.

Owing to the gradual exudation of the juice and the deposition of one layer over another, manna has a stalactitic aspect. The finest pieces are mostly in the form of three-edged sticks, sometimes as much as 6 to 8 inches long and an inch or more wide, grooved on the inner side, which is generally soiled by contact with the bark; of a porous, crystalline, friable structure and of a pale brownish yellow tint, becoming nearly pure white in those parts which have been most distant from the bark of the tree. The pieces which are of deeper colour, and of an unctuous or gummy appearance, are less esteemed. Good manna is crisp and brittle, and melts in the mouth with an agreeable, honey-like sweetness, not entirely devoid of traces of bitterness and acridity. Its odour may be compared to that of honey or moist sugar.

Manna of the best quality dissolves at ordinary temperatures in about six parts of water, forming a clear, neutral liquid. It contains besides mannite, a small proportion of sugar and gum.

The manna which exudes from the older stems and from the lower parts of even young trees, contains more or less considerable quantities of gum and fermentable sugar, as well as extraneous impurities. The less favourable weather of the later summer and autumn promotes an alteration in the composition of the juice, and impairs its property of concreting into a crystalline mass.

=Chemical Composition=—The predominant constituent of manna, at least of the better sorts, is _Manna-sugar_ or _Mannite_, C₆H₈(OH)₆ which likewise occurs, though in much smaller quantity, in many other plants besides _Fraxinus_. Artificially, it is produced by treating glucose, C₆H₁₂O₆, with sodium amalgam, and indirectly in the fermentation of glucose or of cane-sugar. It is isomeric with dulcite or melampyrin; crystallizes in shining prisms or tables, belonging to the rhombic system; melts at 166° C., and in very small quantity may by careful heating be sublimed and decomposed. It dissolves in 6·5 parts of water at 16° C., less freely in aqueous alcohol, very sparingly in absolute alcohol, and not in ether. The solution has an extremely weak rotatory power, and is not altered by boiling with dilute acids or alkalis, or with alkaline cupric tartrate.

Berthelot has shown that mannite is susceptible of fermentation, though not so easily as sugars belonging to the group of carbo-hydrates. The quantity of mannite in the best manna varies from 70 to 80 per cent.

When a solution of manna is mixed with alkaline cupric tartrate, rapid reduction to cuprous hydrate takes place even in the cold. This effect is due to the presence of a sugar which, according to Backhaus (1860), consists of ordinary dextro-glucose. It may amount to as much as 16 per cent., and is found in the best flake manna, but most abundantly in the unctuous varieties. Buignet[1511] has pointed out that the rotatory power of this sugar being inconsiderable, it probably consists of a mixture of _Cane-sugar_ and _Levulose_. He found however that an aqueous solution of manna deviates powerfully to the right, a fact which he considers due to the presence of a large proportion of _Dextrin_. The best kinds of manna, according to Buignet, contain about 20 per cent. of dextrin; the inferior much more.

[1511] _Journ. de Pharm._ vii. (1867) 401; viii. (1868) 5.

In our experiments we have not succeeded in isolating either dextrin or cane-sugar. There is present, even in the finest manna, a small amount of a dextrogyre mucilage, which is precipitated by neutral acetate of lead, and yields mucic acid when boiled with concentrated nitric acid.

Ether extracts from an aqueous solution of manna a very small quantity of red-brown resin, having an offensive odour and sub-acrid taste; together with traces of an acid which reduces silver salts and appears to be easily resinified. The quantity of water in the inferior kinds of manna often amounts to 10 or 15 per cent. The finest manna affords about 3·6 per cent. of ash.

The greenish colour of certain pieces of manna was formerly attributed to the presence of copper, till Gmelin, on account of the fluorescence of the solution, ascribed it to _Æsculin_. It is in reality produced by a body much resembling æsculin, namely _Fraxin_, C₁₆H₁₈O₁₀, occurring in the bark of the manna-ash and of the common ash, and together with æsculin, in that of the horse-chestnut. Fraxin crystallizes in colourless prisms, easily soluble in hot water and in alcohol, and having a faintly astringent and bitter taste. By dilute acids, it is resolved into _Fraxetin_, C₁₀H₈O₃, and _Glucose_, C₆H₁₂O₆. The presence of fraxin in manna, especially in the inferior sorts, is made apparent by the faint fluorescence of the alcoholic manna solution. The smallest fragment of the bark of the ash or the manna-ash immersed in water displays the same fluorescence.

=Commerce=—The exports of manna from Sicily[1512] (chiefly from Palermo) have been as follows:—

1869 1870 1871 2546 cwt., 1564 cwt., 3038 cwt., val. £15,972. val. £10,220. val. £19,528.

About half the quantity is sent to France. Italian commercial statistics[1513] represent the export of manna in 1870 thus:—_in canelli_ 58,691 kilo. (1155 cwt.), _in sorte_ 186,664 kilo. (3676 cwt.). The United Kingdom imported in the year 1870, 230 cwt. of manna, valued at £4447.[1514]

[1512] _Report by Consul Dennis on the Commerce and Navigation of Sicily in 1869, 1870 and 1871._

[1513] Direzione generale delle Gabelle—_Movimento commerciale del regno d’Italia nel 1870_, Milano, 1871.

[1514] _Annual Statement of the Trade and Navigation of the U.K. for 1870_, p. 102.

In 1877 the exports of “canelli” from Messina were 4273 kilogrammes, and of the drug “in sorte” 52,874 kilogr.; total value, 127,145 lire.

=Adulteration=—It can hardly be said that manna is subject to adulteration, though attempts to introduce a spurious manna made of glucose have been recorded. But considerable skill and ingenuity have been expended in converting the inferior sorts of manna into what has the aspect of fine natural Flake Manna, the manufacturers admitting however the factitiousness of their product. The artificial Flake Manna has the closest superficial resemblance to very fine pieces of the natural drug, but differs in its more uniform colour, and in being uncontaminated with the slight impurities, from which natural manna is never wholly free. It differs also in that when broken, no crystals of mannite are to be seen in the interstices of the pieces, and it wants the peculiar odour and slightly bitter flavour of natural manna. If one part of it is boiled with four of alcohol (0·838), a viscid honey-like residue will be obtained, whereas natural manna leaves undissolved a hard substance. Histed[1515] found it to afford about 40 per cent. of mannite, while fine manna similarly treated yielded 70 per cent.

=Uses=—A gentle laxative, much less frequently employed in this country than formerly, but still largely consumed in South America. Mannite, which possesses similar properties, is often prescribed in Italy.

Other sorts of Manna.

Various plants besides _Fraxinus_ afford, under certain conditions, saccharine exudations, some of which constituted the _Oriental Manna_ used in Europe in early times. So far as is known, they differ from officinal manna in containing no mannite.

_Alhagi Manna_; _Turanjabín_ (Arabic); is afforded by _Alhagi Camelorum_ Fisch. (Hedysarum Alhagi Pallas, non L.), a small spiny plant of the order _Leguminosæ_ found in Persia, Afghanistan and Beluchistan. It had already been noticed by Isztachri.[1516] Excellent specimens of the manna, kindly obtained for us in the north-west of India by Dr. E. Burton Brown and Mr. T. W. H. Tolbort, show it as a substance in little roundish, hard, dry tears, varying from the size of a mustard seed to that of a hemp seed, of a light brown colour, agreeable saccharine taste, and senna-like smell. The leaflets, spines and pods of the plant, mixed with the grains of this manna, are characteristic and easily recognizable.

Villiers (1877) showed this manna to contain cane-sugar, a dextrogyrate glucose, and _melezitose_ (see further on: Briançon manna, page 416). Ludwig[1517] had also found some dextrin and mucilage.

Alhagi Manna is collected near Kandahar and Herat, where it is found on the plants at the time of flowering. It is imported into India from Kabul and Kandahar to the extent of about 25 _maunds_ (2000 lb.) annually; its value is reckoned at 30 rupees per _secr_, = 30_s._ per lb.[1518]

[1515] _On artificial Flake Manna_, in _Pharm. Journ._ xi. (1870) 629.

[1516] Tchihatcheff, _l’Asie mineure_, ii. (1856) 355.

[1517] _Archiv der Pharmacie_, 193 (1870) 32-52.

[1518] Stewart, _Punjab Plants_, Lahore (1869) p. 57; Davies, _Report on the trade and resources of the countries on the N. W. boundary of British India_, Lahore, 1862.

_Gaz-anjabin_ (Arabic); _Tamarisk Manna_ (in part)—In the months of June and July, the shrubs of tamarisk (_Tamarix gallica_ var. _mannifera_ Ehrenb.) growing in the valleys of the peninsula of Sinai, especially in the Wady es Sheikh, exude from their slender branches, in consequence of the puncture of an insect (_Coccus manniparus_ Ehrenb.) little honey-like drops, which in the coolness of early morning are found in a solid state. This substance is _Tamarisk Manna_: it is collected by the Arabs, and by them sold to the monks of St. Katharine, who dispose of it to the pilgrims visiting the convent. Tamarisk Manna is also produced (but is perhaps no longer collected?) in Persia, where it is called _Gaz-angabín_;[1519] and probably likewise in the Punjab,[1520] from which regions it may have been brought to Europe in ancient times.

A specimen of tamarisk manna brought from Sinai, examined in 1861 by Berthelot, had the appearance of a thick yellowish syrup, contaminated with vegetable remains. It was found to consist of cane-sugar, inverted sugar (lævulose and glucose), dextrin and water, the last constituting one-fifth of the whole.[1521]

Although the name _Gaz-angabín_ signifies _tamarisk-honey_, it is used according to Haussknecht[1522] at the present time in Persia, to designate certain round cakes, common in all the bazaars, of which the chief constituent is a manna collected in the mountain districts of Chahar-Mahal and Faraidan, and especially about the town of Khonsar, south-west of Ispahan, from _Astragalus florulentus_ Boiss. et Haussk. and _A. adscendens_ Boiss. et Haussk. The best sorts of this manna, which are termed _Gaz Alefi_ or _Gaz Khonsari_, are obtained in August by shaking it from the branches, the little drops finally sticking together and forming a dirty, greyish-white, tough mass. The commoner sort got by scraping the stem, is still more impure. The specimen of it brought by Haussknecht yielded to Ludwig[1523] dextrin, uncrystallizable sugar and organic acids.

_Shir-khist_—Ancient writers on materia medica as Garcia d’Orta (1563) mention a sort of manna known by this name. The substance is still found in the bazaars of North-western India, being imported in small quantity from Afghanistan and Turkistan.[1524] Haussknecht in his paper on Oriental Manna already quoted, states that it is the exudation of _Cotoneaster nummularia_ Fisch. et Mey. (_Rosaceæ_), also of _Atraphaxis spinosa_ L. (_Polygonaceæ_), and that it is brought chiefly from Herat. We have to thank Dr. E. Burton Brown of Lahore, and Mr. Tolbort for specimens of this manna, which, from fragments it contains, is without doubt derived from a _Cotoneaster_. It is in irregular roundish tears, from about ¼ up to ¾ of an inch in greatest length, of an opaque dull white, slightly clammy, and easily kneaded in the fingers. It has a manna-like smell, a pure sweet taste and crystalline fracture. With water, it forms a syrupy solution with an abundant residue of starch granules.

Shír-khist was found by Ludwig to consist of an exudation analogous to tragacanth, but containing at the same time two kinds of gum, an amorphous levogyre sugar, besides starch and cellulose.

_Oak Manna_—The occurrence of a saccharine substance on the oak is noticed by both Ovid and Virgil, and it is also mentioned by the Arabian physicians, as Ibn Baytar[1525] and Elluchasem Elimithar.[1526] The last named, who died A.D. 1052, states that the exudation appears upon the oaks in the region of Diarbekir. At the present day, it is the object of some industry among the wandering tribes of Kurdistan, who, according to Haussknecht, collect it from _Quercus Vallonea_ Kotschy and _Q. persica_ Jaub. et Spach. These trees are visited in the month of August by immense numbers of a small white _Coccus_, from the puncture of which a saccharine fluid exudes, and solidifies in little grains. The people go out before sunrise, and shake the grains of manna from the branches on to linen cloths, spread out beneath the trees. The exudation is also collected by dipping the small branches on which it is formed, into vessels of hot water, and evaporating the saccharine solution to a syrupy consistence, which in this state is used for sweetening food, or is mixed with flour to form a sort of cake.

[1519] Angelus, _Pharm. Persica_ (see appendix) p. 359.

[1520] Stewart, _op. cit._ p. 92.

[1521] _Comptes Rendus_, liii. (1861) 583; _Pharm. Journ._ iii. (1862) 274.

[1522] _Archiv d. Pharmacie_, 192 (1870) 246.

[1523] _Loc. cit._

[1524] Davies in the work quoted at page 414, note 4.

[1525] Ed. Sontheimer, i. (1840) 375.

[1526] _Tacuini Sanitatis_, Argentorati (1531) 24.

A fine specimen of the Oak Manna of Diarbekir was sent to the London International Exhibition of 1862. It constituted a moist soft mass of agglutinated tears, much resembling an inferior sort of ash-manna, and had an agreeable saccharine taste.

A less pure form of this manna occurs as a compact, greyish, saccharine mass, sometimes hard enough to be broken with a hammer. It consists of sugary matter, mixed with abundance of small fragments of green leaves, and has a herby smell and pleasant sweet taste. A sample of it brought from Diarbekir, examined by one of us, yielded 90 per cent. of dextrogyre sugar, which could not be obtained in a crystalline state, though it exists in such condition in the crude drug. Starch and dextrine were entirely wanting.[1527]

A specimen furnished to Ludwig[1528] by Haussknecht afforded much mucilage, a small amount of starch, about 48 per cent. of dextrogyre grape sugar, with traces of tannic acid and chlorophyll.

_Briançon Manna_—This is a white saccharine substance which, in the height of summer and in the early part of the day, is found adhering in some abundance to the leaves of the larch (_Pinus Larix_ L.), growing on the mountains about Briançon in Dauphiny. It was formerly collected for use in medicine, but only to a very limited extent, for it was rare in Paris in the time of Geoffroy (1709-1731), and at the present day has quite disappeared from trade, though still gathered by the peasants. A specimen collected for one of us near Briançon in 1854, consists of small, detached, opaque, white tears, many of them oblong and channelled, and encrusting the needle-like leaf of the larch; they have a sweet taste and slight odour.[1529] Under the microscope they exhibit indistinct crystals.

Briançon manna has been examined in 1858 by Berthelot, who detected in it a peculiar sugar termed _Melezitose_, answering to the formula C₁₂H₂₂O₁₁ + OH₂.

Several other saccharine exudations have been observed by travellers and naturalists; we shall simply enumerate the more remarkable, referring the reader for further information to the original notices.

_Pirus glabra_ Boiss. affords in Luristan a substance which, according to Haussknecht, is collected by the inhabitants, and is extremely like Oak Manna. It is stated by the same traveller that _Salix fragilis_ L., and _Scrophularia frigida_ Boiss., likewise yield in Persia saccharine exudations. A kind of manna was anciently collected from the cedar, _Pinus Cedrus_ L.[1530] Manna is yielded in Spain by _Cistus ladaniferus_ L.[1531] _Australian Manna_, which is in small rounded, opaque, white, dry masses, is found on the leaves of _Eucalyptus viminalis_ Labill. It contains a kind of sugar called _Melitose_,[1532] has a sweet thistle, is devoid of medicinal properties and is not collected for use.[1533]

[1527] Further particulars, see Flückiger, _Ueber die Eichenmanna von Kurdistan_, in _Archiv der Pharmacie_, 200 (1872) 159.

[1528] _Loc. cit._ p. 35.

[1529] Hanbury, _Science Papers_, p. 438.

[1530] Geoffroy, _Mat. Med._ ii. (1741) 584.

[1531] Dillon, _Travels through Spain_ (1780) p. 127.

[1532] Gmelin, _Chemistry_, xv. 296.

[1533] _Pharm. Journ._ iv. (1863) 108.

The substance named _Tigala_ (corrupted into _Trehala_), from which a peculiar sugar has been obtained,[1534] is the coccoon of a beetle, and not properly a saccharine exudation.[1535]

The _Lerp Manna_ of Australia is also of animal origin.[1536] It consists of water 14, white thread-like portion 33, sugar 53 parts. The threads possess some of the characteristic properties of starch, from which they differ entirely by their form and unalterability even in boiling water. Yet in sealed tubes, they dissolve in 30 parts of water at 135° C. The sugar is dextrogyre; it impregnates the threads as a soft brown amorphous mass. In the purified state it does not crystallize, even after a long time. By means of dilute sulphuric acid, the threads are converted into crystalline grape sugar.

OLEUM OLIVÆ.

_Olive Oil_; _Salad Oil_; F. _Huile d’Olives_; G. _Olivenöl_; _Baumöl_; _Provencer Oel_.

=Botanical Origin=—_Olea europæa_ L., an evergreen tree,[1537] seldom exceeding 40 feet in height, yet attaining extreme old age, abundantly cultivated in the countries bordering the Mediterranean, up to an elevation of about 2000 feet above the sea-level.[1538] _Olea ferruginea_ Royle (_O. cuspidata_ Wallich), a tree abundant in Afghanistan, Beluchistan and Western Sind, has been supposed to be a wild form of _O. europæa_, but is regarded by Brandis[1539] as a distinct species. It is not known to have been ever cultivated, yet its fruit, which is of a small size and but sparingly produced, is capable of affording a good oil.

_History_—In ancient Egypt the olive was known by the term _bāk_; it can be traced as far as the 17th century before our era.[1540]

According to the elaborate investigations of Ritter[1541] and of A. De Candolle,[1542] the olive tree is a native of Palestine, and perhaps of Asia Minor and Greece. Its original area also extends over north-eastern Africa; Schweinfurth[1543] regards it as undoubtedly wild on the mountains of Elbe and Soturba in lat. 22 N. on the western shores of the Red Sea, a locality which he visited in 1868. The olive tree has also been met with as far eastward as the country of the Gallas, where it is much appreciated as affording excellent timber.[1544] It is also stated by Theophrastus, that in his time the tree was plentiful in the Cyrenaica, the modern Barca, in northern Africa.

[1534] _Comptes Rendus_, xlvi. (1858) 1276; Gmelin, _Chemistry_, xv. 299.

[1535] Belon, _Singularitez_ (1554) l. 2. cap. 91; Guibourt, _Comptes Rendus_ (1858) 1213; Hanbury, _Journ. Linn. Soc._, Zoology, iii. (1859) 178; also _Science Papers_, 158.

[1536] Dobson, _Proceedings of Royal Society of Van Diemen’s Land_, i. (1851) 234; _Pharm. Journ._ iv. (1863) 108; Flückiger, _Wittstein’s Vierteljahresschrift_, xvii. (1868) 161; _Archiv der Pharmacie_, 196 (1871) 7; abstracted in the _Yearbook of Pharmacy_, 1871. 188.

[1537] Readers desiring full information about the olive tree, its oil, its history, etc., should refer to the extremely exhaustive work of Coutance, _l’Olivier_, Paris, 1877, 456 pages, 120 figures.

[1538] Grisebach states the elevation above the sea of olive-cultivation thus:—Portugal (Algarve) 1400 feet; Sierra Nevada 3000; do., southern slope 4200; Nice 2400; Etna 2200; Macedonia 1200; Cilicia 2000.—_Die Vegetation der Erde nach ihrer klimatologischen Anordnung_, i. (1872) 262. 283. 342.

[1539] _Forest Flora of North-western and Central India_, 1874, 307.

[1540] Brugsch-Bey, _Reise nach der grossen Oase Kargeh_, Leipzig, 1878. 80. etc.—See also _Journ. of Botany_, 1879. 52.

[1541] _Erdkunde von Asien_, vii. (