Chapter XXXVII: Part 37

Groups of crystals of calcium oxalate are frequent in the middle and inner bark, but the chief constituents of the cells are brown granules of colouring matter and tannin. As the thickness of the bark increases the liber is pushed more to the outside, the middle cortical layer being partly thrown off by secondary cork-formation (rhytidoma, see pp. 354 and 538). Hence the younger barks, which alone are medicinal, are widely different from the older in structure and appearance.

=Chemical Composition=—The most interesting constituent is a peculiar kind of tannin. Stenhouse pointed out in 1843 that the tannic acid of oak bark is not identical with that of nutgalls; and such many years afterwards was proved to be the case.

The first-named substance, now called _Querci-tannic Acid_, yields by destructive distillation pyrocatechin, and according to Johanson (1875) very little pyrogallol. By boiling it with dilute sulphuric acid querci-tannic acid is split up into a red derivative and sugar. A solution of gelatine is precipitated by querci-tannic acid as well as by gallo-tannic acid; yet the compound formed with the latter is very liable to putrefaction, whereas the tannin of oak bark, which is accompanied by a large amount of extractive matter, furnishes a stable compound, and is capable of forming good leather.

As querci-tannic acid has not yet been isolated in a pure state, the exact estimation of the strength of the tanning principle in oak bark has not been accomplished, although it is important from an economic as well as from a scientific point of view. The method of Neubauer (1873) depends upon the amount of permanganate of potassium decomposable by the extract of a given weight of oak bark. Neubauer found in the bark of young stems, as grown for tanning purposes, from 7 to 10 per cent. of querci-tannic acid, soluble in cold water.

Braconnot (1849) extracted from the seeds of the oaks under notice a crystallized sugar, which was shown in 1851 by Dessaignes to be a peculiar substance, which he termed _Quercite_. Prunier proved (1877-1878) that it agrees with the formula C₆H₇(OH)₅ + 4 OH₂, and is closely allied to kinic acid, C₆H₇(OH)₄COOH (see page 363). Quercite gives off water at 100°, melts at 225° C., and again losing water yields a crystallized anhydride. In the oak bark extremely small quantities of quercite appear also to be present, as pointed out by Johanson.

A colourless, crystallizable, bitter substance, soluble in water, but not in absolute alcohol or ether, was extracted from oak bark in 1843 by Gerber, and named _Quercin_. It requires further examination: Eckert (1864) could not detect its existence in young oak bark.

=Uses=—Occasionally employed as an astringent, chiefly for external application.

GALLÆ HALEPENSES.

_Gallæ Turcicæ_; _Galls_, _Nutgalls_,
_Oak Galls_, _Aleppo_ or _Turkey Galls_;
F. _Noix de Galle_, _Galle d’Alep_;
G. _Levantische oder Aleppische Gallen_,
_Galläpfel_.

=Botanical Origin=—_Quercus lusitanica_ Webb, var. _infectoria_ (_Q. infectoria_ Oliv.),[2227] a shrub or rarely a tree, found in Greece, Asia Minor, Cyprus and Syria. It is probable that other varieties of this oak, as well as allied species, contribute to furnish the Aleppo galls of commerce.

=History=—Oak galls are named by Theophrastus, and were well known to other ancient writers. Alexander Trallianus prescribed them as a remedy in diarrhœa.[2228]

The earliest accurate descriptions and figures of the oak and the insect producing the galls are due to Olivier.[2229] Pliny[2230] mentions the interesting fact that paper saturated with an infusion of galls may be used as a test for discovering sulphate of iron, when added as an adulteration to the more costly verdigris: this, according to Kopp, is the earliest instance of the scientific application of a chemical reaction.[2231] For tanning and dyeing, galls have been used from the earliest times, during the middle ages however they were not precisely an article of great importance, being then, no doubt, for a large part replaced by sumach.

Nutgalls have long been an object of commerce between Western Asia and China. Barbosa in his _Description of the East Indies_[2232] written in 1514 calls them _Magican_,[2233] and says they are brought from the Levant to Cambay by way of Mekka, and that they are worth a great deal in China and Java. From the statements of Porter Smith[2234] we learn that they are still prized by the Chinese.

[2227] De Candolle, _Prodromus_, xvi. sect. 2. fasc. i. 17.

[2228] Puschmann’s edition, quoted in the Appendix, i. 237.

[2229] _Voyage dans l’Empire Othoman_, ii. (1801), pl. 14-15.

[2230] Lib. 34. c. 26.

[2231] _Geschichte der Chemie_, ii. (1844) 51.

[2232] Published by the Hakluyt Society, Lond. 1866. 191.

[2233] Nearly the same name is still used in the Tamil, Telugu, Malayalim and Canarese languages.

[2234] _Mat. Med. and Nat. Hist. of China_, 1871. 100.

=Formation=—Many plants are punctured by insects for the sake of depositing their eggs, which operation gives rise to those excrescences which bear the general name of _gall_.[2235]

Oaks are specially liable to be visited for this purpose by insects of the order _Hymenoptera_ and the genus _Cynips_, one species of which, _Cynips Gallæ tinctoriæ_ Olivier (_Diplolepis Gallæ tinctoriæ_ Latreille), occasions the galls under notice.

The female of this little creature is furnished with a delicate borer or ovipositor, which she is able to protrude from the extremity of the abdomen; by means of it she pierces the tender shoot of the oak, and deposits therein one or more eggs. This minute operation occasions an abnormal affluence to the spot of the juices of the plant, the result of which is the growth of an excrescence often of great magnitude, in the centre of which (but not as it appears until the gall has become full-grown) the larva is hatched and undergoes its transformations.

When the larva has assumed its final development and become a winged insect, which requires a period of five to six months, the latter bores itself a cylindrical passage from the centre of the gall to its surface, and escapes.

In the best kind of gall found in commerce, this stage has not yet arrived, the gall having been gathered while the insect is still in the larval state. In splitting a number of galls, it is not difficult to find specimens in all stages, from those containing the scarcely distinguishable remains of the minute larva, to those which show the perfect insect to have perished when in the very act of escaping from its prison.

=Description=—Aleppo galls[2236] are spherical, and have a diameter of ⁴/₁₀ to ⁸/₁₀ of an inch. They have a smooth and rather shining surface, marked in the upper half of the gall by small pointed knobs and ridges, arranged very irregularly and wide apart; the lower half is more frequently smooth. The aperture by which the insect escapes is always near the middle. When not perforated, the galls are of a dark olive green, and comparatively heavy; but after the fly has bored its way out, they become of a yellowish-brown hue, and lighter in weight. Hence the distinction in commerce of _Blue_ or _Green Galls_, and _White Galls_.

[2235] French writers, as Moquin-Tandon, distinguish the thick-walled galls of _Cynips_ from the thin, capsular galls formed by _Aphis_, terming the former _galles_ and the latter _coques_ (shells).

[2236] There are many other varieties of oak gall, for descriptions of some of which, see Guibourt, _Hist. des Drogues_, ii. (1869) 292; and for information on the various gall-insects of the family _Cynipsidæ_ and the excrescences they produce, consult a paper by Abl in Wittstein’s _Vierteljahresschrift für prakt_. _Pharm._ vi. (1857) 343-361.

Aleppo galls are hard and brittle, splitting under the hammer; they have an acidulous, very astringent taste followed by a slight sweetness, but have no marked odour. Their fractured surface is sometimes close-grained, with a waxy or resinous lustre; sometimes (especially towards the kernel-like centre) loosely granular, or sometimes again it exhibits a crystalline-looking radiated structure or is full of clefts. The colour of the interior varies from pale brown to a deep greenish yellow. The central cavity, sometimes nearly ¼ of an inch in diameter, which served as a dwelling for the insect, is lined with a thin hard shell. If the insect has perished while still very young, the central cavity and the aperture contain a mass of loose starchy cellular tissue, or its pulverulent remains: if the insect has not been developed at all, the centre of the gall is entirely composed of this tissue.

=Microscopic Structure=—The cellular tissue of the gall is formed in the middle layer of large spherical cells with rather thick porous walls, becoming considerably smaller towards the circumference. The outermost rows are built up of cells having but a very small lumen and comparatively thick walls, so that they form a sort of rind. Here and there throughout the entire tissue, there occur isolated bundles of vessels which pass through the stalk into the gall. Towards the kernel, the parenchyme gradually passes into radially-extended, wider, thin-walled cells, the walls of which are marked with spiral striæ. The hard shell of the chamber[2237] is composed of larger, radially-extended, thick-walled cells, with beautifully stratified porous walls. On the inner side of this shell there are found, after the escape of the insect, the remains of the starchy tissue already mentioned, which originally filled the chamber and had been consumed by the insect as nourishment.

[2237] _Couche protectrice_ of Lacaze-Duthiers—_Recherches pour servir à l’histoire des galles_.—_Ann. des Sciences Nat._, Bot. xix. (1853) 273-354.

The parenchyme-cells outside the shell contain chlorophyll and tannin; the latter is in transparent, colourless, sharp-edged masses, insoluble in benzol, but dissolving slowly in water, quickly in alcohol. Thin slices soaked in glycerin appear after some time covered with beautiful crystals of gallic acid. The thick-walled cells (stone-cells) and the neighbouring striated cells, are rich in octahedra of calcium oxalate. The tissue of the gall situated within the shell of thick-walled cells contains starch in large, compressed, mostly spherical granules; also isolated masses of brown resin. Besides these, there appears to be in this part of the tissue an albuminoid compound.

=Chemical Composition=—The rough taste of galls is due to their chief constituent, _Tannic_ or _Gallo-tannic Acid_, C₁₄H₁₀O₉, or

C₆H₂(OH)₂COOH}
}O
C₆H₂(OH)₂CO}

the type of a numerous family of substances to which vegetables owe their astringent properties. Tannic matter was long supposed to be of one kind, namely that found in the oak gall, but the researches of later years have proved the tannin of different plants to possess distinctive characters: hence the term _gallo-tannic_ acid to distinguish that of galls, from which it is principally derived. It was however shown by Stenhouse as far back as the year 1843, again in 1861, as well as by still more recent unpublished experiments, that the tannic acid found in Sicilian sumach, the leaves of _Rhus Coriaria_ L., is identical with that of oak galls. Löwe in 1873 came to the same conclusion. The best oak galls yield of this acid, from 60 to 70 per cent.

_Gallic Acid_ is also contained in galls ready-formed to the extent of about 3 per cent. Free sugar, resin, protein-substances, have also been found. Neither gum nor dextrin is present.

=Commerce=—The introduction into dyeing of new chemical substances, and the increased employment of sumach and myrobalans, have caused the trade in nutgalls to decline considerably during the last few years. The province of Aleppo which used to export annually 10,000 to 12,000 quintals, exported in 1871 only 3000 quintals.[2238] A staple market for the galls which are collected in the mountains of Kurdistan is Diarbekir, whence they are sent to Trebizond for shipment. Galls are also shipped in some quantity at Bussorah, Bagdad, Bushire, and Smyrna.

There were imported into the United Kingdom from ports of Turkey and Persia during 1872, 6349 cwt. of galls, valued at £18,581.

=Uses=—Oak galls in their crude state are seldom used in medicine unless it be externally; but the tannic and gallic acids extracted from them are often administered.

Other kinds of Gall.

_Chinese or Japanese Galls_—The only kind of galls, besides those of the oak, which are of commercial importance. They are described at page 167.

_Pistacia Galls_—The genus _Pistacia_, which belongs to the same order as _Rhus_, is very liable to the attacks of _Aphis_, which produce upon its leaves and branches excrescences of exactly the same nature as Chinese galls. In the south of Europe, horn-like follicles, often several inches long,[2239] are frequently met with on the branches of _Pistacia Terebinthus_ (page 165). These _Gallæ vel Folliculi Pistacinæ_, in Italian _Carobbe di Giudea_, were formerly used in medicine and in dyeing.[2240] They were noticed in 1555 by Belon, but already well known as early as the time of Theophrastus.

Another much smaller gall of different shape is formed (by the same insect?) on the ribs of the leaves of _Pistacia Terebinthus_; _P. Lentiscus_ (page 161) affords also a similar small excrescence.

Again, another growth of the same character constitutes the small and very astringent galls known in the Indian bazaars by the names of _Bazghanj_ and _Gule-pistah_, the latter signifying _flower of pistachio_; they have been termed in Europe _Bokhara Galls_. They were imported by sea into Bombay in the year 1872-73, to the extent of 184 cwt., chiefly from Sind;[2241] and are also carried into North-western India by way of Peshawar and by the Bolan Pass. Occasionally a package finds its way into a London drug sale.

_Tamarisk Galls_—These are roundish knotty excrescences of the size of a pea up to ½ an inch in diameter, found in North-western India on the branches of _Tamarix orientalis_ L., a large, quick-growing tree, common on saline soils. The galls are used in India in the place of oak galls, and are mentioned as “non-officinal” in the _Pharmacopœia of India_, 1867. We are not aware that they have been the subject of any particular chemical research; their microscopic structure has been investigated by Vogl.[2242]

[2238] Consul Skene—_Reports of H. M. Consuls_, No. 1. 1872. 270.

[2239] For a figure, see _Pharm. Journ._ iii. (1844) 387. For the structure see Marchand, in the paper quoted at page 166, note 4, plate iii.

[2240] Analysis by Martius may be found in Liebig’s _Ann. d. Pharm._ xxi. (1837) 179.

[2241] From the returns quoted at page 333, note 3.

[2242] _Zeitschrift des Oesterreichischen Apothekervereines_, 1877. 14.

SANTALACEÆ.

LIGNUM SANTALI.

_Lignum Santalinum album vel citrinum_; _Sandal-wood_; F. _Bois de Santal citrin_; G. _Weisses oder Gelbes Sandelholz_.

=Botanical Origin=—_Santalum album_[2243] L., a small tree, 20 to 30 feet high, with a trunk 18 to 35 inches in girth, a native of the mountainous parts of the Indian peninsula, but especially of Mysore and parts of Coimbatore and North Canara, in the Madras Presidency; it grows in dry and open places, often in hedge-rows, not in forests. The same tree is also found in the islands of the Eastern Archipelago, notably of Sumba (otherwise called Chandane or Sandal-wood Island), and Timur.

In later times, sandal-wood has been extensively collected in the Hawaiian or Sandwich Islands, where its existence was first pointed out about the year 1778, from _Santalum Freycinetianum_ Gaud. and _S. pyrularium_ A. Gray;[2244] in the Viti or Fiji Islands from _S. Yasi_ Seem.; in New Caledonia from _S. austro-caledonicum_, Vieill;[2245] and in Western Australia from _Fusanus spicatus_ Br. (_Santalum spicatum_ DC., _S. cygnorum_ Miq.).[2246] The mother plants of _Japanese_ and _West Indian_ sandal-wood are not known to us.

In India the sandal-wood tree is protected by Government, and is the source of a profitable commerce. In other countries it has been left to itself, and has usually been extirpated, at least from all accessible places, within a few years of its discovery.

=History=—Sandal-wood, the Sanskrit name for which, _Chandana_, has passed into many of the languages of India, is mentioned in the _Nirukta_ or writings of Yaska, the oldest Vedic commentary extant, written not later than the 5th century B.C. The wood is also referred to in the ancient Sanskrit epic poems, the _Rāmāyana_ and _Mahabharata_, parts of which may be of nearly as early date.

The author of the _Periplus of the Erythrean Sea_, written about the middle of the 1st century, enumerates sandal-wood (Ξύλα σαγαλίνα) among the Indian commodities imported into Omana in the Persian Gulf.[2247]

The Τζανδάνα mentioned towards the middle of the 6th century by Cosmas Indicopleustes,[2248] as brought to Taprobane (Ceylon) from China and other emporia, was probably the wood under consideration. In Ceylon its essential oil was used as early as the 9th century in embalming the corpses of the princes.

[2243] Fig. in Bentley and Trimen’s _Medic. Plants_, part 18 (1877).

[2244] Seemann, _Flora Vitiensis_, 1865-73. 210-215.

[2245] The natural woods having been nearly exhausted, the tree is now under culture in the island. _Catalogue des produits des colonies françaises, Exposition de 1878_, p. 332; they state there that the island of Nossi-bé, on the north-western coast of Madagascar, also supplies some sandal-wood.

[2246] Whether _Santalum lanceolatum_ Br., a tree found throughout N. and E. Australia, and called _sandal-wood_ by the colonists, is an object of trade, we know not.

[2247] Vincent, _Commerce and Navigation of the Ancients_, ii. (1807) 378.

[2248] Migne, _Patrologiæ Cursus_, series Græca, tom. 88. 446.

Sandal-wood is named by Masudi[2249] as one of the costly aromatics of the Eastern Archipelago. In India it was used in the most sacred buildings, of which a memorable example still exists in the famous gates of Somnath, supposed to be 1000 years old.[2250]

In the 11th century sandal-wood was found among the treasures of the Egyptian khalifs, as stated in our article on camphor at page 511.

Among European writers, Constantinus Africanus, who flourished at Salerno in the 11th century, was one of the earliest to mention Sandalum.[2251] Ebn Serabi, called Serapion the Younger, who lived about the same period, was acquainted with _white_, _yellow_, and _red_ sandal-wood.[2252] All three kinds of sandal-wood also occur in a list of drugs[2253] in use at Frankfort, _circa_ A.D. 1450; and in the _Compendium Aromatariorum_ of Saladinus, published in 1488, we find mentioned as proper to be kept by the Italian apothecary,—“_Sandali trium generum, scilicet albi, rubii et citrini_.”

Whether the _red_ sandal here coupled with _white_ and _yellow_ was the inodorous wood of _Pterocarpus santalinus_, now called _Lignum santalinum rubrum_ or _Red Sanders_ (see p. 199), is extremely doubtful. It may have meant real sandal wood, of which three shades, designated _white_, _red_, and _yellow_, are still recognized by the Indian traders.[2254]

On the other hand, we learn from Barbosa[2255] that about 1511 _white_ and _yellow_ sandal-wood were worth at Calicut on the Malabar Coast from eight to ten times as much as the _red_, which would show that in his day the red was not a mere variety of the other two, but something far cheaper, like the Red Sanders Wood of modern commerce.

In 1635 the subsidy levied on sandal-wood imported into England was 1_s._ per lb. on the _white_, and 2_s._ per lb. on the _yellow_.[2256]

[2249] I. 222 in the work quoted in the Appendix.

[2250] They are 11 feet high and 9 feet wide, and richly carved out of sandal-wood; they were constructed for the temple of Somnath in Guzerat, once esteemed the holiest temple in India. On its destruction in A.D. 1025, the gates were carried off to Ghuzni in Afghanistan, where they remained until the capture of that city by the English in 1842, when they were taken back to India. They are now preserved in the citadel of Agra. For a representation of the gates, see _Archæeologia_, xxx. (1844) pl. 14.

[2251] Opera, Basil. 1536-39, _Lib. de Gradibus_, 369.

[2252] _Liber Serapionis aggregatus in medicinis simplicibus_, 1473.

[2253] Flückiger, _Die Frankfurter Liste_, Halle, 1873. 11.

[2254] Thus Milburn in his _Oriental Commerce_ (1813) says—“ ... the deeper the colour, the higher is the perfume; and hence the merchants sometimes divide sandal into _red_, _yellow_, and _white_, but these are all different shades of the same colour, and do not arise from any difference in the species of the tree.”—(i. 291.)

[2255] Ramusio, _Navigationi et Viaggi_, etc., Venet. 1554. fol. 357 b., _Libro di Odoardo Barbosa Portoghese_.

[2256] _The Rates of Marchandizes_, Lond. 1635.

The first figure and satisfactory description of _Santalum album_ occur in the _Herbarium Amboinense_ of Rumphius (ii. tab. 11).

=Production=—The dry tracts producing this valuable wood occupy patches of a strip of country lying chiefly in Mysore and Coimbatore, about 250 miles long, north and north-west of the Neilgherry Hills, and having Coorg and Canara between it and the Indian Ocean; also a piece of country further eastward in the districts of Salem and North Arcot, where the tree grows from the sea-level up to an elevation of 3000 feet. In Mysore, where sandal-wood is most extensively produced, the trees all belong to Government, and can only be felled by the proper officers. This privilege was conferred on the East India Company by a treaty with Hyder Ali, made 8 August 1770, and the monopoly has been maintained to the present day. The Mysore animal exports of sandal wood are about 700 tons, valued at £27,000.[2257] They are shipped from Mangalore.

A similar monopoly existed in the Madras Presidency until a few years ago, when it was abandoned. But sandal-wood is still a source of revenue to the Madras Government, which by the systematic management of the Forest Department has of late years been regularly increasing. The quantity of sandal-wood felled in the Reserved Forests during the year 1872-3 was returned as 15,329 maunds (547½ tons).[2258]

The sandal-wood tree, which is indigenous to the regions just mentioned, used to be reproduced by seeds sown spontaneously or by birds; but it is now being raised in regular plantations, the seeds being sown two or three in a hole with a chili (_Capsicum_) seed, the latter producing a quick-growing seedling which shades the sandal while young.[2259] It is probable that the nurse-plant affords _sustenance_, for it has been shown[2260] that _Santalum_ is parasitic, its roots attaching themselves by tuber-like processes to those of many other plants; and it is also said that young sandal plants thrive best when grass is allowed to grow up in the seed-beds.

The trees attain their prime in 20 to 30 years, and have then trunks as much as a foot in diameter. A tree having been felled, the branches are lopped off, and the trunk allowed to lie on the ground for several months, during which time the white ants eat away the greater part of the inodorous sapwood. The trunk is then roughly trimmed, sawn into billets 2 to 2½ feet long, and taken to the forest depots. There the wood is weighed, subjected to a second and more careful trimming, and classified according to quality. In some parts it is customary not to fell but to dig the tree up; in others the root is dug up after the trunk has been cut down,—the root affording valuable wood, which with the chips and sawdust are preserved for distillation, or for burning in the native temples. The sap wood and branches are worthless.[2261]

[2257] B. H. Baden Powell, _Report on the Administration of the Forest Department in the several provinces under the Government of India_, 1872-73, Calcutta, 1874. vol i. 27.

[2258] _Report of the Administration of the Madras Presidency during the year 1872-73_, Madras, 1874. 18. 143.

[2259] Beddome, _Flora Sylvatica for Southern India_, 1872. 256.

[2260] Scott in _Journ. of Agricult. and Horticult. Soc. of India_, Calcutta, vol. ii. part 1 (1871) 287.

[2261] Elliot, _Experiences of a Planter in the Jungles of Mysore_, ii. (1871) 237; also verbal information communicated by Capt. Campbell Walker, Deputy Conservator of Forests, Madras.

In 1863 a sort of sandal-wood afforded by _Fusanus spicatus_ (p. 599) was one of the chief exports of Western Australia, whence it was shipped to China. A trifling payment for permission to cut growing timber of any kind was the only barrier placed on the felling of the trees. The farmers employed their teams during the dull season in bringing to Perth or Guildford the logs of sandal which had been felled and trimmed in the bush; and there was a flourishing trade so long as trees of a fair size could be obtained within 100 or even 150 miles of the towns, where the commodity was worth £6 to £6 10_s._ per ton. But the ill-regulated and improvident destruction of the trees in the more easily accessible districts has so reduced their numbers that the trade in that part of Australia soon came to an end.[2262] Australian sandal-wood appears however to be still an article of commerce, if one may draw such an inference from the fact that 47,904 cwt. of sandal wood were imported into Singapore from Australia in the year 1872. It was mostly re-shipped to China.[2263]

=Description=—sandal-wood is not much known in English commerce, and is by no means always to be found even in London. That which we have examined, and which we believe was Indian, was in cylindrical logs, mostly about 6 inches in diameter (the largest 8 inches—smallest 3: inches) and 3 to 4 feet long, extremely ponderous; the bark had been removed. A transverse section of sandal-wood exhibits it of a pale brown, marked with rather darker concentric zones and (when seen under a lens) numerous open pores. The tissue is traversed by medullary rays, also perceptible by the aid of a lens. The wood splits easily, emitting when comminuted an agreeable odour which is remarkably persistent; it has a strongish aromatic taste.

The varieties of sandal-wood are not classified by the few persons who deal in the article in London, and we are unable to point out characters by which they may be distinguished. In the price-currents of commercial houses in China three sorts of sandal-wood are enumerated, namely, _South Sea Island_, _Timor_, and _Malabar_; the last fetches three or four times as high a price as either of the others. Even the Indian sandal-wood may vary in an important manner. Beddome,[2264] conservator of forests in Madras, and an excellent observer, remarks that the finest sandal-wood is that which has grown slowly on rocky, dry and poor land; and that the trees found in a rich alluvial soil, though of very fine growth, produce no heartwood and are consequently valueless. A variety of the tree with more lanceolate leaves (var. β _myrtifolium_ DC.), native of the eastern mountains of the Madras Presidency, affords a sandal-wood which is nearly inodorous.

=Microscopic Structure=—The woody rays or wedges show a breadth varying from 35 to 420 mkm., the primary being frequently divided by secondary medullary rays. These latter rays consist of one, often of two, rows of cells of the usual form. The woody tissue which they enclose is chiefly made up of small ligneous fibres with pointed ends, some larger parenchymatous cells, and thick-walled vessels. The resin and essential oil reside chiefly in the medullary rays, as shown by the darker colour of these latter.

=Chemical Composition=—The most important constituent is the essential oil, which the wood yields to the extent of from 2 to 5 per cent.[2265] In India, with imperfect stills, 2·5 per cent. of the oil are obtained; the roots yield the largest amount and the finest quality of it.[2266] It is a light yellow, thick liquid, possessing the characteristic odour of sandal; that which we examined had a sp. gr. of 0·963. We did not succeed in finding a fixed boiling point of the oil; it began to boil at 214° C., but the temperature quickly rose to 255°, the oil acquiring a darker hue. Oil of sandal-wood varies much in the strength and character of its aroma, according to the sort of wood from which it is produced.

[2262] Millett, _An Australian Parsonage_, Lond., 1872, 43. 95. 382.

[2263] _Straits Settlements Blue Book for 1872_, Singapore, 1873. 298. 347.—It is possible that the sandal-wood in question may have been the produce of the South Sea Islands, shipped from an Australian port.

[2264] _Op. cit._

[2265] Information obligingly communicated by Messrs. Schimmel and Co., Leipzig (1878).

[2266] Dr. Bidie, in _Pharmacopœia of India_, 1868, p. 461.

The oil as largely prepared by Messrs. Schimmel & Co., in a column 100 millimetres long, deviates the plane of polarization 18·6° to the _left_. Oil of Venezuela sandal-wood, from the same distillers, examined in the same manner, deviates 6°·75 to the _right_.

From the wood, treated with boiling alcohol, we obtained about 7 per cent. of a blackish extract, from which a tannate was precipitated by alcoholic solution of acetate of lead. Decomposed by sulphuretted hydrogen, the tannate yielded a tannic acid having but little colour, and striking a greenish hue with a ferric salt. The extract also contained a dark resin.

=Commerce=—The greatest trade in sandal-wood is in China, which country in the year 1866 imported at the fourteen treaty ports then open 87,321 peculs, equivalent to 5,197 tons; of this vast quantity the city of Hankow on the river Yangtsze, received no less than 61,414 peculs, or more than seven times as much as any other port.[2267] The imports into Hankow have recently been much smaller, namely, 14,989 peculs in 1871 and 12,798 peculs in 1872.[2268] On the other hand, Shanghai lying near the mouth of the same great river, imported in 1872, 59,485 peculs of sandal-wood, the estimated value of which was about £100,000. In 1877 the imports of all China were 72,934 peculs.

A considerable trade in sandal-wood is done in Bombay, the quantity imported thither annually being about 650 tons, and the animal export about 400 tons.[2269]

Oil of sandal-wood is largely manufactured on the ghats between Mangalore and Mysore, where fuel for the stills is abundant. Official returns[2270] represent the quantity of the oil imported into Bombay in the year 1872-73 as 10,348 lbs., value £8,374; 4,500 lbs. were re-exported by sea.

=Uses=—The essential oil has of late been prescribed as a substitute for copaiba, otherwise sandal-wood has hardly any uses in modern European medicine. It is employed as a perfume and for the fabrication of small articles of ornament. Among the natives of India it is largely consumed in the celebration of sepulchral rites, wealthy Hindus showing their respect for a departed relative by adding sticks of sandal-wood to the funereal pile. The powder of the wood made into a paste with water is used for making the caste mark, and also for medicinal purposes. The consumption of sandal-wood in China appears to be principally for the incense used in the temples.

[2267] _Reports on Trade at the ports in China open to foreign trade for 1866_, published by order of the Inspector-General of Customs, Shanghai, 1867. 120. 121.—One pecul = 133⅓ lb.

[2268] _Commercial Reports of H. M. Consuls in China for 1871_ (p. 50) and 1872 (pp. 62. 159).

[2269] From the official document quoted at p. 601, note 1.

[2270] See p. 333, note 3.

_Gymnosperms._

CONIFERÆ.

TEREBINTHINA VULGARIS.

_Crude or Common Turpentine_; F. _Térebenthine commune_; G. _Gemeiner Terpenthin_.

=Botanical Origin=—The trees which yield Common Turpentine may be considered in two groups, namely, European and American.

1. _European_—In Finland and Russia Proper, the Scotch Pine, _Pinus sivestris_ L.; in Austria and Corsica, _P. Laricio_ Poiret; and in South-western France, _P. Pinaster_ Solander (_P. maritima_ Poiret), extensively cultivated as the _Pin maritime_, yield turpentine in their respective countries.

2. _American_—In the United States, the conifers most important for terebinthinous products are the Swamp Pine, _Pinus australis_ Michaux (_P. palustris_ Mill.), and the Loblolly Pine, _P. Tæda_ L.

=History=—The resin of pines and firs was well known to the ancients, who obtained it in much the same manner as that practised at the present day. The turpentine used in this country has for many years past been derived from North America. Up to the last century, both it and the substance called _Common Frankincense_ were imported from France. The late civil war in the United States and the blockade of the Southern ports, occasioned a great scarcity of American turpentine; and terebinthinous substances from all other countries were poured into the London market. The actual supplies, however, were mainly furnished by France.

Kopp[2271] quotes a passage showing that the essential oil of turpentine was known to Marcus Græcus, who termed it _Aqua ardens_. This almost unknown personage is the reputed inventor of _Greek Fire_, a dreaded engine of destruction in mediæval warfare.

=Secretion=—The primary formation of resin-ducts in the bark of coniferous trees has been explained by Dippel,[2272] Müller,[2273] and Frank.[2274] The subsequent diffusion of the resinous juice through the heartwood, sapwood, and bark, has been elaborately investigated by Hugo von Mohl.[2275] From the various forms under which this diffusion exists in the different species have arisen the diverse methods of obtaining the terebinthinous resins.

[2271] _Geschichte der Chemie_, iv. (1847) 392.

[2272] _Botanische Zeitung_, 1863.

[2273] Pringsheim, _Jahrb. für wissenschaftl. Botanik._ 1866.

[2274] _Beiträge zur Pflanzenphysiologie_, Leipzig, 1868. 119.

[2275] _Botanische Zeitung_, 1859. 329.

Thus in the wood of the Silver Fir (_Pinua Picea_ L.) resin-ducts are altogether wanting;—and led by experience, the Alpine peasant collects the turpentine of this tree by simply puncturing the little cavities which form under its bark. In the Scotch Pine (_P. silvestris_ L.), they are more abundant in the wood than in the bark, a fact which might be anticipated by observing how rarely this tree exudes resin spontaneously.

Oil of turpentine, like volatile oils in general, undergoes on exposure to the air certain alterations giving rise to what is called _resinification_. The formic acid which is produced in small quantity during this change characterizes it as one of oxidation; the chief products however are not exactly known, and not one of them has been proved identical with any natural resin. The common assumption that resins are produced from volatile oils by simple oxidation, is consequently not yet entirely justified.

=Extraction=—In the United States[2276] turpentine is obtained to the largest extent from _Pinus australis_, of which tree there are vast forests, the piny woods or pine-barrens, extending from Virginia to the Mexican Gulf, especially through North and South Carolina, Georgia and Alabama. But it is in North Carolina that the extraction of turpentine is principally carried on.

In the winter, _i.e._ from November to March, the negroes in a _Turpentine Orchard_, as the district of forest to be worked is called, are occupied in making in the trunks of the trees, cavities which are technically known as _boxes_. For this purpose a long narrow axe is used, and some skill is required to wield it properly. The boxes are made from 6 to 12 inches above the ground, and are shaped like a distended waistcoat-pocket, the bottom being about 4 inches below the lower lip, and 8 or 10 below the upper. On a tree of medium size, a box should be made to hold a quart. The less the axe approaches the centre of the tree the better, as vitality is the less endangered. An expert workman will make a box in less than 10 minutes. From one to four boxes are made in each tree, a few inches of bark being left between them. The greater number of trees from which turpentine is now obtained, are from 12 to 18 inches in diameter, and have three boxes each.

The boxes having been made, the bark and a little of the wood immediately beneath it, which are above the box, are _hacked_; and from this excoriation, the sap begins to flow about the middle of March, gradually filling the box. Each tree requires to be freshly hacked every 8 or 10 days, a very slight wound above the last being all that is needed. The hacking is carried on year after year, until it reaches 12 to 15 feet or more, ladders being used. The turpentine, which is called _dip_, is removed from the boxes by a spoon or ladle of peculiar form, and collected into barrels, which are made on the spot and are of very rude construction. The first year’s flow of a new tree, having but a small surface to traverse before it reaches the box, is of special goodness and is termed _Virgin dip_.

[2276] The account here given is taken from F. L. Olmsted’s _Journey in the Seaboard Slave States_, New York, 1856, p. 338, etc.

The turpentine which concretes upon the trunk is occasionally scraped off and barrelled by itself, and is known in the market as _scrape_, or by English druggists as _Common Frankincense_ or _Gum thus_.

Although a large amount of turpentine is shipped to the northern ports for distillation, a still larger is distilled in the neighbourhood of the turpentine orchards. Copper stills are used, capable of containing 5 to 20 barrels of turpentine. The turpentine is distilled without water, the volatile oil as it flows from the worm being received in the barrel in which it is afterwards sent to market. When all the oil that can be profitably drawn off has been obtained, a spigot is removed from an opening in the bottom of the still, and the residual _Rosin_, appearing as a viscid fluid-like molasses, is allowed to flow out. Only the first qualities of rosin, as that obtained from _Virgin dip_, are generally considered worth saving, the less pure sorts being simply allowed to run to waste. When it is intended to save the rosin, the latter is drawn off into a vat of water, which separates the chips and other rubbish, and the rosin is then placed in barrels for the market. A North Carolina turpentine orchard will remain productive under ordinary treatment for fifty years.

The collection of turpentine in the departments of the Landes and Gironde in the south-west of France, is performed in a more rational manner than in America, inasmuch as the plan of making deep cavities in the tree for the purpose of receiving the resin, is avoided by the simple expedient of placing a suitable vessel beneath the lowest incision.[2277] The turpentine which concretes upon the stem is termed in France _Galipot_ or _Barras_.

[2277] For further particulars, see Guibourt, _Hist. des drog._ ii. (1869) 259, also Curie, _Produits résineux du Pin maritime_. Paris 1874. 24 pages, 1 plate; Matthieu, _Flore forestière_ 1860, p. 353.

=Description=—Common turpentine is chiefly of two varieties, namely, _American_ and _Bordeaux_; the first alone is commonly found in the English market.

_=American Turpentine=_—A viscid honey-like fluid, of yellowish colour, somewhat opaque, but becoming transparent by exposure to the air; it has an agreeable odour and warm bitterish taste. When long kept in a bottle, it is seen to separate into two layers, the upper clear and faintly fluorescent, the lower somewhat turbid or granular. When the latter portion is examined under the microscope, it is found to consist mainly of minute crystals of peculiar curved or bluntly elliptic form. These crystals are abietic acid; when the turpentine is warmed, the crystals are speedily dissolved.

_Bordeaux Turpentine_—in all essential particulars agrees with American Turpentine; it appears to separate rather more readily than the latter into two layers,—a transparent and an opaque or crystalline.

=Chemical Composition=—The turpentines are mixtures of resin and essential oil. The latter, which amounts to from 15 to 30 per cent., consists for the greater part of various hydrocarbons, corresponding to the formula C₁₀H₁₆. Many of the crude turpentine oils, and some of them even after rectification, are energetically acted on by metallic sodium. This reaction proves the presence of a certain quantity of oxygenated oils, not one of which has thus far been isolated.

The turpentine oils, although agreeing in composition, exhibit a series of physical differences according to their origin. One and the same tree, indeed, yields from its several organs oils of different properties. The boiling point varies between 152° and 172° C. The sp. gr. at mean temperatures ranges from 0·856 to 0·870. Greater differences are exhibited in the optical properties, some varieties of the oil turning the plane of polarization to the right, others to the left. This rotatory power differs in many cases from that of the turpentine from which the oil was derived.[2278] The odour of oil of turpentine varies with the species from which it has been obtained.

When crude turpentine is distilled with water, nearly the whole of the oil passes over, while the resin remains. This resin is called _Colophony_ or _Rosin_. When it still contains a little water, it is distinguished in English trade as _Yellow Rosin_; when fully deprived of water, it becomes what is called _Transparent Rosin_. That of deeper colour acquired by a still longer application of heat, bears the name of _Black Rosin_.

Colophony softens at 80° C., and melts completely at 100° into a clear liquid. At about 150° it forms a somewhat darker liquid, but without undergoing a loss in weight; at higher temperatures, it gradually decomposes. Pure colophony has a sp. gr. of 1·07, and is homogeneous, transparent, amorphous, and very brittle. At temperatures between 15° and 20° C., it requires for solution 8 parts of dilute alcohol (0·883). On addition of a caustic alkali, it dissolves in spirit much more freely. It is plentifully soluble in acetone or benzol.

The composition of colophony agrees with the formula C₄₄H₆₂O₄. By shaking coarsely powdered colophony with warm dilute alcohol, it is converted into a crystalline body, _Abietic Acid_, C₄₄H₆₄O₅,—a result due simply to hydration. Under such treatment, colophony yields 80 to 90 per cent. of abietic acid,[2279] and therefore consists chiefly of the anhydride of that acid. This is probably the case with the resins of other conifers. The living tree contains only the anhydride, for the fresh resinous juice is clear and amorphous after the expulsion of the oil; and when exposed to the air it loses oil, takes up water and solidifies as the crystalline acid,—a change which may easily be traced by the aid of the microscope, in drops taken direct from the trunk. Amorphous colophony retains its transparency even in a moist atmosphere, and appears to be capable of passing into the state of abietic acid, only when the assumption of the needful molecule of water is aided, in nature by the presence of the essential oil, or artificially by that of alcohol.

[2278] For some particulars, see my notice in the _Jahresbericht_ of Wiggers and Husemann for 1869, p. 36.—F. A. F.

[2279] Flückiger in _loc. cit._ 1867. 36.—Most chemists assign to this acid the formula C₂₀H₃₀O₂, and call it _silvic acid_.

Colophony when boiled with alkaline solutions forms greasy salts of abietic acid, the so-ccalled _resin-soaps_, which are used as additions to other soaps.

Siewert’s _Silvic Acid_ is regarded by Maly (1864) as a product of the decomposition of abietic acid; and the _Pimaric_, _Pinic_ and _Silvic Acids_ of former investigators, as impure abietic acid. Pimaric acid however, which is the chief constituent of _Galipot_, appears to be decidedly different, so far as we can judge from the experiments of Duvernoy (1865) and of one of ourselves (F.).

Abietic acid, as well as the unaltered coniferous resins, deviate the ray of polarized light, whereas American colophony, dissolved in acetone, is devoid of optical power.

=Commerce=—The supplies of turpentine are chiefly derived from the United States, but the trade has undergone a great change, as shown by the following figures, which represent the quantities imported in the several years:—

1869 1870 1871 1872
60,468 cwt. 51,257 cwt. 2,231 cwt. 1,000 cwt.

This greatly diminished importation of the crude article is partially explained by a larger importation of Oil of Turpentine and Rosin; but the increase is by no means sufficient to account for the vast diminution indicated by the above figures. The quantities of these latter articles imported into the United Kingdom during the year 1872 were as follows:—_Oil of Turpentine_, 220,292 cwt., value £470,085, six-sevenths being furnished by the United States of America and the remainder chiefly by France. _Rosin_, 919,494 cwt., value £492,246; of this quantity, the United States supplied nine-tenths, and France the larger part of the remainder.[2280]

=Uses=—Turpentine, Common Frankincense and Colophony are ingredients of certain plasters and ointments. Oil of turpentine is occasionally administered internally as a vermifuge or diuretic, and applied externally as a stimulant. But these substances are immeasurably less important in medicine than in the arts.

Thus Americanum vel vulgare.

This substance, known among druggists as _Common Frankincense_ or _Gum Thus_, is the resin which, as explained at p. 605, concretes upon the stems of the pines in the American turpentine orchards, and is there called _Scrape_. It corresponds to the _Galipot_ or _Barras_ of the French, which in old times supplied its place.

It is a semi-opaque, softish resin, of a pale yellow colour, smelling of turpentine; it is generally mixed with pine leaves, bits of wood and other impurities, so that it requires straining before it is used. By keeping, it becomes dry and brittle, of deeper colour and milder odour. Under the microscope, it exhibits a crystalline structure due to _Abietic Acid_, of which it chiefly consists. It is imported from America in barrels, but in insignificant quantities and only for the druggist’s use. Sometimes, however, it is distilled as common turpentine.

Dry pine resin, of which Common Frankincense is the type, evolves when heated an agreeable smell; hence in ancient times it was commonly used in English churches in place of the more costly olibanum. At present it is scarcely employed except in a few plasters.

[2280] _Annual Statement of the Trade of the U.K. for 1872._ pp. 53. 56. 60. 210.

TEREBINTHINA VENETA.

_Terebinthina Laricina_; _Venice Turpentine_,
_Larch Turpentine_; F. _Térébenthine de
Venise ou de Briançon_, _Térébenthine du
mélèze_; G. _Venetianischer Terpenthin_,
_Lärchen-Terpenthin_.

=Botanical Origin=—_Pinus Larix_ L. (_Larix europæa_ DC.), a tall forest tree of the mountains of Southern Central Europe, from Dauphiny through the Alps to Styria and the Carpathians, ascending to an elevation of 3000 to 5500 feet above the sea-level. It is largely grown in plantations in England and also, since 1738, in Scotland.

=History=—The turpentine of the larch was known to Dioscorides as imported from the Alpine regions of Gaul.[2281] Pliny also was acquainted with it, for he correctly remarks that it does not harden. Galen in the 2nd century also mentions it, admitting that it may well be substituted for Chian turpentine (see p. 165), the true, legitimate _Terebinthina_. Yet even in the beginning of the 17th century many pharmacologists complained of such a substitution. Mattioli[2282] gave an account of the method of collecting it about Trent in the Tirol, by boring the trees to the centre, which is true to the present day. It used formerly to be exported from Venice, then the great emporium for drugs of all kinds; the turpentine may even at times have been collected in the territories of the Venetian republic. We find it expressly called _Terebinthina Veneta_ by Guintherus of Andernach.[2283]

The name _larch_ seems to belong to the turpentine rather than to the tree. Dioscorides says the resin is called by the natives λάρικα, and a similar name is mentioned by Galen. In Pasi’s _Tariffa de pesi e misure_, 1521 (see Appendix), we find “_Termentina sive Larga_,”—and _larga_ is still an Italian name for larch turpentine. The peasants of the Southern Tirol call it _Lerget_, and in Switzerland the common name in German is _Lörtsch_.

=Extraction=—Larch turpentine is collected in the Tirol, chiefly about Mals, Meran, Botzen and Trent. A very small amount is obtained occasionally in the Valais in Switzerland, and in localities in Piedmont and France where the larch is found. The resin is obtained from the heartwood, by making in the spring a narrow cavity reaching to the centre of the stem at about a foot from the ground. This is then stopped up until the autumn of the same or of the following year, when it is opened and the resin taken out with an iron spoon. If only one hole is thus made, the tree yields about half a pound yearly without appreciable detriment. But if on the other hand a number of wide holes are made, and especially if they are left open, as was formerly the practice in the Piedmontese and French Alps, a larger product amounting to as much as 8 lb. is obtained annually, but the tree ceases to yield after some years, and its wood is much impaired in value.

[2281] Lib. i. cap. 92.

[2282] _Comment. in libr. i. Dioscoridis_, Venetiis, 1565. 106.

[2283] _De medicina veteri et nova etc._, Basileæ, 1571. 183.

Mohl, who witnessed the collection of this turpentine in the Southern Tirol,[2284] observed that when a growing larch stem was sawn through, the resin flowed most abundantly from the heartwood, and in smaller quantity, though somewhat more quickly, from the sapwood, and that the bark contained but few resin-ducts. The practice of closing the cavities is adopted, not only for the sake of preserving the wood and for the greater convenience of removing the turpentine, but also because it tends to maintain the transparency and purity of the latter.

=Description=—Venice turpentine is a thick, honey-like fluid, slightly turbid, yet not granular and crystalline; it has a pale yellowish colour and exhibits a slight fluorescence. Its odour resembles that of common turpentine, but is less powerful; its taste is bitter and aromatic. When exposed to the air, it thickens but slowly to a clear varnish, and hardens but very slowly when mixed with magnesia. Larch turpentine, though common on the Continent, is seldom imported into England,[2285] and the article sold for it is almost always spurious.

=Chemical Composition=—Larch turpentine dissolves in spirit of wine, forming a clear liquid which reddens litmus; hot water agitated with it also acquires a faint acid reaction, due to formic and probably also to succinic acid. Glacial acetic acid, amylic alcohol, and acetone mix with it perfectly. By distillation it yields on an average 15 per cent. of essential oil of the composition, C₁₀H₁₆, which boils at 157° C., and when saturated with dry hydrochloric acid gas, easily produces crystals of the compound C₁₀H₁₆ + HCl. The residual resin is soluble in two parts of warm alcohol of 75 per cent., and more copiously in concentrated alcohol.

Two parts of the turpentine diluted with one of benzol or acetone deviate the ray of polarized light 9·5° to the _right_. The essential oil deviates 6·4° to the _left_; the resin perfectly freed from volatile oil and dissolved in half its weight of acetone, deviates 12·6° to the _right_ in a column 50 mm. long.

We have not succeeded in preparing a crystallized acid from the resin of Venice turpentine, although its composition according to _Maly_ (1864) is the same as that of American colophony, which is easily transformed into crystallized abietic acid.

=Uses=—Venice turpentine appears to possess no medicinal properties that are not equally found in other substances of the same class, and as a medicine it has fallen into disuse. But in name at least it is in frequent requisition for horse and cattle medicines.

=Adulteration=—Alston (1740-60) said of Venice turpentine[2286] that it is seldom found in the shops,—a remark equally true at the present day, for but few druggists trouble themselves to procure it genuine. The Venice turpentine usually sold is an artificial mixture of common resin and oil of turpentine, which may be easily distinguished from the product of the larch by the facility with which it dries when spread on a piece of paper,[2287] and by its stronger turpentine smell.

[2284] _Botanische Zeitung_, xvii. (1859) 329, abstracted in the _Jahresbericht_ of Wiggers, 1859. 18.

[2285] On one occasion I observed Venice Turpentine in a public drug sale in London, 21 barrels imported from Trieste being offered, 14 July, 1864.—D. H.

[2286] _Lectures on the Materia Medica_, Lond. ii. (1770) 398.

[2287] Thus if a thin layer of true Venice turpentine and another of common turpentine be spread on two sheets of paper it will be found after the lapse of some weeks that the former cannot be touched without adhering to the fingers, while the latter will have become a dry, hard varnish.

CORTEX LARICIS.

_Larch Bark._

=Botanical Origin=—_Pinus Larix_ L.—see p. 609.

=History=—The bark of the larch has long been known to possess astringent properties; hence it has been used in tanning. Gerarde,[2288] who wrote near the close of the 16th century, likened it to that of the pine, which he described to be of a binding nature; but there is no evidence that it was an officinal drug.

About the year 1858 larch bark was recommended by Dr. Frizell of Dublin, and afterwards by other physicians, as a stimulating astringent and expectorant. In consequence of the favourable effects which have resulted from its use it has been included in the _Additions to the Pharmacopœia of 1867_.

=Description=—The bark that we have seen is in flattish pieces or large quills, externally reddish-brown. In those taken from older wood there is a large amount of an exfoliating corky coat, displaying as it is removed bright rosy tints, while the liber is of a different texture, slightly fibrous and whitish. The inner surface is smooth and of a pinkish-brown, or pale yellow. The bark breaks with a short fracture, exhaling an agreeable balsamic terebinthinous odour; it has a well-marked astringent taste. For medicinal use the inner bark is to be preferred.

=Microscopic Structure=—A transverse section exhibits resin-ducts, but far less numerous than in the bark of many allied trees. The medullary rays are not very distinct. Throughout the middle layer of the bark large isolated thick-walled cells of very irregular shape are scattered.