AMYGDALÆ DULCES.

Sweet Almonds; F. Amandes douces; G. Süsse Mandeln.

Botanical Origin—Prunus Amygdalus Baillon[937] var. β. dulcis (Amygdalus communis L. var. β. dulcis DC.)—The native country of the almond cannot be ascertained with precision. A. de Candolle,[938] after reviewing the statements of various authors concerning the occurrence of the tree in an apparently wild state, arrives at the conclusion that its original area possibly extended from Persia, westward to Asia Minor and Syria, and even to Algeria. The tree is found ascending to 4000 feet in the Antilebanon, to 3000 in Mesopotamia, and even to 9000 feet in the Avroman range, not far from Sulemānia, Southern Kurdistan.[939]

At an early period the tree was spread throughout the entire Mediterranean region, and in favourable situations, far into the continent of Europe. It was apparently introduced into Italy from Greece, where according to Heldreich,[940] the bitter variety is truly wild. The almond-tree matures its fruit in the south of England, but is liable to destruction by frost in many parts of central Europe.

History—The earliest notice of the almond extant is that in the Book of Genesis,[941] where we read that the patriarch Israel commanded his sons to carry with them into Egypt a present consisting of the productions of Palestine, one of which is named as almonds.

From the copious references to the almond in the writings of Theophrastus, one cannot but conclude that in his day it was familiarly known.

In Italy, M. Porcius Cato[942] mentions towards the middle of the 2nd century b.c. Avellanæ Græcæ which we know from later authors signified almonds. Columella, who wrote about a.d.. 60, calls them Nuces Græcæ. Bitter almonds (“Amygdali amari”) are named about this latter period by Scribonius Largus.

As to more northern Europe, almonds are mentioned together with other groceries and spices as early as a.d. 716, in a charter granted by Chilperic II., King of France, to the monastery of Corbie in Normandy.[943] In 812 Charlemagne ordered the trees (Amandalarii) to be introduced on the imperial farms. In the later middle ages, the cultivation of the almond was carried on about Speier and in the Rhenish Palatinate. We learn from Marino Sanudo[944] that in the beginning of the 14th century, almonds had become an important item of the Venetian trade to Alexandria. They were doubtless in large part produced by the islands of the Greek Archipelago, then under Christian rule. In Cyprus for instance, the Knights Templar levied tithes in 1411 of almonds, honey, and sesamé seed.[945]

The consumption of almonds in mediæval cookery was enormous. An inventory made in 1372 of the effects of Jeanne d’Evreux, queen of France, enumerates only 20 lb. of sugar, but 500 lb. of almonds.[946]

In the Form of Cury, a manuscript written by the master cooks of King Richard II., a.d. 1390, are receipts for “Creme of Almand, Grewel of Almand, Cawdel of Almand Mylke, Jowt of Almand Mylke,” &c.[947]

Almonds were sold in England by the “hundred” i.e. 108 lb. Rogers[948] gives the average price between 1259 and 1350 as 2d., and between 1351 and 1400 as 3⅛d. per lb.

Description—The fruit of the almond tree is a drupe, with a velvety sarcocarp which at maturity dries, splits, and drops out leaving bare and still attached to the branch, an oblong, ovate pointed stone, pitted with irregular holes. The seed, about an inch in length, is ovate or oblong, more or less compressed, pointed at the upper, blunt at the lower end, coated with a scurfy, cinnamon-brown skin or testa. It is connected with the stone or putamen by a broad funicle, which runs along its edge for more than a third of its length from the apex; hence the raphe passes downwards to the rounded end of the seed, where a scar marks the chalaza. From this, a dozen or more ramifying veins run up the brown skin towards the pointed end. After an almond has been macerated in warm water, the skin is easily removed, bringing with it the closely attached translucent inner membrane or endopleura. As the seed is without albumen, the whole mass within the testa consists of embryo. This is formed of a pair of plano-convex cotyledons, within which lie the flat leafy plumule and thick radicle, the latter slightly projecting from the pointed or basal end of the seed.

Almonds have a bland, sweet, nutty flavour. When triturated with water, they afford a pure white, milk-like emulsion of agreeable taste.

Varieties—The different sorts of almond vary in form and size, and more particularly in the firmness of the shell. This in some varieties is tender and easily broken in the hand, in others so hard as to require a hammer to fracture it. The form and size of the kernel likewise exhibit some variation. The most esteemed are those of Malaga, known in trade as Jordan Almonds. They are usually imported without the shell, and differ from all other sorts in their oblong form and large size. The other kinds of sweet almonds known in the London market are distinguished in the order of value as Valencia, Sicily, and Barbary.[949]

Microscopic Structure—Three different parts are to be distinguished in the brown coat of an almond. First, a layer of very large (as much as ⅓ mm. in diameter) irregular cells, to which the scurfy surface is due. If these brittle cells are boiled with caustic soda, they make a brilliant object for microscopic examination in polarized light. The two inner layers of the skin are made up of much smaller cells, traversed by small fibro-vascular bundles. The brown coat assumes a bluish hue on addition of perchloride of iron, owing to the presence of tannic matter.

The cotyledons consist of thin-walled parenchyme, fibro-vascular bundles being not decidedly developed. This tissue is loaded with granular albuminous matter, some of which exhibits a crystalloid aspect, as may be ascertained in polarized light. Starch is altogether wanting in almonds.

Chemical Composition—The sweet almond contains fixed oil extractable by boiling ether to the extent of 50 to 55 per cent. A produce of 50 per cent. by the hydraulic press is by no means uncommon.

The oil (Oleum Amygdalæ) is a thin, light yellow fluid, of sp. gr. 0·92, which does not solidify till cooled to between -10 and-20° C. When fresh, it has a mild nutty taste, but soon becomes rancid by exposure to the air; it is not, however, one of the drying oils. It consists almost wholly of the glycerin compound of Oleic Acid, C₁₈H₃₄O₂.

Almonds easily yield to cold water a sugar tasting like honey, which reduces alkaline cupric tartrate even in the cold, and is therefore in part grape sugar. Pelouze however (1855) obtained from almonds 10 per cent. of cane-sugar. The amount of gum appears to be very small; Fleury (1865) found that the total amount of sugar, dextrin and mucilage was altogether only 6·29 per cent.

If almonds are kept for several days in alcohol, crystals of asparagine (see article Rad. Althææ, p. 93) make their appearance, as shown by Henschen (1872), and by Portes (1876).

The almond yields 3·7 per cent. of nitrogen, corresponding to about 24 per cent. of albuminoid matters. These have been elaborately examined by Robiquet (1837-38), Ortloff (1846), Bull (1849), and Ritthausen (1872).[950] The experiments tend to show that there exist in the almond two different protein substances; Robiquet termed one of these bodies Synaptase, while others applied to it the name Emulsin.[951] Commaille (1866) named the second albuminous substance Amandin; it is the Almond-legumin of Gmelin’s Chemistry, the Conglutin of Ritthausen. Emulsin has not yet been freed from earthly phosphates which, when it is precipitated by alcohol from any aqueous solution, often amount to a third of its weight. Amandin may be precipitated from its aqueous solution by acetic acid. According to Ritthausen, these bodies are to be regarded as modifications of one and the same substance, namely vegetable casein.

Blanched almonds comminuted yield, when slightly warmed with dilute potash, a small quantity of hydrocyanic acid and of ammonia; the former may be made manifest by means of Schönbein’s test pointed out at p. 250.

The ash of almonds, amounting to from 3 to nearly 5 per cent., consists chiefly of phosphates of potassium, magnesium and calcium.

Production and Commerce—The quantity of almonds imported into the United Kingdom in 1872 was 70,270 cwt., valued at £204,592. Of this quantity, Morocco supplied 33,500 cwt., and Spam with the Canary Islands 22,000 cwt., the remainder being made up by Italy, Portugal, France, and other countries. The imports into the United Kingdom in 1876 were 77,169 cwt., valued at £244,078. Almonds are largely shipped from the Persian Gulf: in the year 1872-73, there were imported thence into Bombay, 15,878 cwt., besides 3,049 cwt. from other countries.[952]

Uses—Sweet almonds may be used for the extraction of almond oil, yet they are but rarely so employed (at least in England) on account of the inferior value of the residual cake. The only other use of the sweet almond in medicine is for making the emulsion called Mistura Amygdalæ.

AMYGDALÆ AMARÆ.

Bitter Almonds; F. Amandes amères; G. Bittere Mandeln.

Botanical Origin—Prunus Amygdalus Baillon var. a. amara (Amygdalus communis L. var. a. amara DC.). The Bitter Almond tree is not distinguished from the sweet by any permanent botanical character, and its area of growth appears to be the same (see p. 244).

History—(See also preceding article.) Bitter almonds and their poisonous properties were well known in the antiquity, and used medicinally during the middle ages. Valerius Cordus prescribed them as an ingredient of trochisci.[953]

As early as the beginning of the present century, it was shown by the experiments of Bohm, a pharmaceutical assistant of Berlin, that the aqueous distillate of bitter almonds contains hydrocyanic acid and a peculiar oil which cannot be obtained from sweet almonds. It was then inferred that hydrocyanic acid itself might be poisonous, a fact which, strange to say, had not been noticed by Scheele, when he discovered that acid in 1782, as obtained by distilling potassium ferrocyanate with sulphuric acid. The dangerous action of hydrocyanic was then ascertained in 1802 and 1803 by Schaub and Schrader.[954]

Description—Bitter almonds agree in outward appearance, form, and structure with sweet almonds; they exist under several varieties, but there is none so far as we know that in size and form resembles the long sweet almond of Malaga.[955] In general, bitter almonds are of smaller size than sweet. Triturated with water, they afford the same white emulsion as sweet almonds, but it has a strong odour of hydrocyanic acid and a very bitter taste.

Varieties—These are distinguished in their order of goodness, as French, Sicilian, and Barbary.

Microscopic Structure—In this respect, no difference between sweet and bitter almonds can be pointed out. If thin slices of the latter are deprived of fat oil by means of benzol, and then kept for some years in glycerin, an abundance of crystals is slowly formed, of what we suppose to be amygdalin.

Chemical Composition—Bitter almonds, when comminuted and mixed with water, immediately evolve the odour of bitter almond oil. The more generally diffused substances are the same in both kinds of almond, and the fixed oil in particular of the bitter almond is identical with that of the sweet. Bitter almonds however contain on an average a somewhat lower proportion of oil than the sweet. In one instance that has come to our knowledge in which 28 cwt. of bitter almonds were submitted to pressure, the yield of oil was at the rate of 43·6 per cent. Mr. Umney, director of the laboratory of Messrs. Herrings and Co., where large quantities of bitter almonds are submitted to powerful hydraulic pressure, gives 44·2 as the average percentage of oil obtained during the years 1871-2.

Robiquet and Boutron-Charland in 1830 prepared from bitter almonds a crystalline substance, Amygdalin, and found that bitter almond oil and hydrocyanic acid can no longer be obtained from bitter almonds, the amygdalin of which has been removed by alcohol. Liebig and Wöhler in 1837 showed that it is solely the decomposition of this body (under conditions to be explained presently), that occasions the formation of the two compounds above named. Disregarding secondary products (ammonia and formic acid), the reaction takes place as represented in the following equation:

This memorable investigation first brought under notice a body of the glucoside class, now so numerous.

Amygdalin may be obtained crystallized when almonds deprived of their oil are boiled with alcohol of 84 to 94 per cent. The product amounts at most to 2½ or 3 per cent. Amygdalin per se dissolves in 15 parts of water at 8-12° C., forming a neutral, bitter, inodorous liquid, quite destitute of poisonous properties.

It would appear from the investigations of Portes (1877) that in young almonds, amygdalin is formed before the emulsin.

When bitter almonds have been freed from amygdalin and fixed oil, cold water extracts from the residue chiefly emulsin and another albuminoid matter separable by acetic acid. The emulsin upon addition of alcohol falls down in thick flocks, which, after draining, form with cold water a slightly opalescent solution. This liquid added to an aqueous solution of amygdalin, renders it turbid, and developes in it bitter almond oil. The reaction takes place in the same manner, if the emulsin has not been previously purified by acetic acid and alcohol, or if an emulsion of sweet almonds used. But after boiling, an emulsion of almonds is no longer capable of decomposing amygdalin.

What alteration the emulsin itself undergoes in this reaction, or whether it suffers any alteration at all, has not been clearly made out. The reaction does not appear to take place necessarily in atomic proportions; it does not cease until the emulsin has decomposed about three times its own weight of amygdalin, provided always that sufficient water is present to hold all the products in solution.

The leaves of Prunus Lauro-cerasus L., the bark of P. Padus L., and the organs of many allied plants, also contain emulsin or a substance analogous to it, not yet isolated. In the seeds of various plants belonging to natural orders not botanically allied to the almond, as for example in those of mustard, hemp, and poppy, and even in yolk of egg, albuminous substances occur which are capable of acting upon amygdalin in the same manner. Boiling dilute hydrochloric acid induces the same decomposition, with the simultaneous production of formic acid.

The distillation of bitter almonds is known to offer some difficulties on account of the large quantity present of albuminous substances, which give rise to bumping and frothing. Michael Pettenkofer (1861) has found that these inconveniences may be avoided by immersing 12 parts of powdered almonds in boiling water, whereby the albuminous matters are coagulated, whereas the amygdalin is dissolved. On then adding an emulsion of only 1 part of almonds (sweet or bitter), the emulsin contained in it will suffice to effect the required decomposition at a temperature not exceeding 40° C. In this manner, Pettenkofer obtained in some experiments performed with small quantities of almonds, as much as 0·9 per cent. of essential oil. In the case alluded to on the opposite page, in which 28 cwt. of almonds were treated, the yield of essential oil amounted to 0·87 per cent. From data obligingly furnished to us by Messrs. Herrings and Co. of London, who distill large quantities of almond cake, it appears that the yield of essential oil is very variable. The yearly averages as taken from the books of this firm, show that it may be as low as 0·74, or as high as 1·67 per cent., which, assuming 57 pounds of cake as equivalent to 100 pounds of almonds, would represent a percentage from the latter of 0·42 and 0·95 per cent. respectively. Mr. Umney explains this enormous variation as due in part to natural variableness in the different kinds of bitter almond, and in part to their admixture with sweet almonds. He also states that the action of the emulsin on the amygdalin when in contact with water, is extremely rapid, and that 200 pounds of almond marc are thoroughly exhausted by a distillation of only three hours.

In the distillation, the hydrocyanic acid and bitter almond oil unite into an unstable compound. From this, the acid is gradually set free, and partly converted into cyanide of ammonium and formic acid. Supposing bitter almonds to contain 3·3 per cent. of Amygdalin, they must yield 0·2 per cent. of hydrocyanic acid. Pettenkofer obtained by experiment as much as 0·25 per cent., Feldhaus (1863) 0·17 per cent.

Some manufacturers apply bitter almond oil deprived of hydrocyanic acid, but such purified oil is very prone to oxidation, unless carefully deprived of water by being shaken with fused chloride of calcium. The sp. gr. of the original oil is 1·061-1·065; that of the purified oil (according to Umney) 1·049. The purification by the action of ferrous sulphate and lime, and re-distillation, as recommended by Maclagan (1853), occasions, we are informed, a loss of about 10 per cent.

Bitter almond oil, C₆H₅(COH), being the aldehyde of benzoic acid, C₆H₅(COOH), is easily converted in that acid by spontaneous or artificial oxidation. The oil boils at 180°C. and is a little soluble in water; 300 parts of water dissolve one part of the oil.

There are a great number of plants which if crushed, moistened with water, and submitted to distillation, yield both bitter almond oil and hydrocyanic acid. In many instances the amount of hydrocyanic acid is so extremely small, that its presence can only be revealed by the most delicate test,—that of Schönbein.[956]

Among plants capable of emitting hydrocyanic acid, probably always accompanied with bitter almond oil, the tribes Pruneæ and Pomeæ of the rosaceous order may be particularly mentioned.

The farinaceous rootstocks of the Bitter Cassava, Manihot utilissima, Pohl, of the order Euphorbiaceæ, the source of tapioca in Brazil, have long been known to yield hydrocyanic acid.

A composite, Chardinia xeranthemoides Desf., growing in the Caspian regions, has been shown by W. Eichler also to emit hydrocyanic acid.[957] The same has been observed by the French in Gaboon[958] with regard to the fruits of Ximenia americana L. of the order Olacineæ, and the fact has been confirmed by Ernst of Caracas,[959] near which place the plant abounds. Mr. Prestoe of the Botanical Garden, Trinidad, informs us (1874) that in that island a convolvulaceous plant, Ipomœa dissecta Willd., contains a juice with a strong prussic acid odour. According to Lösecke, a common mushroom, Agaricus oreades Bolt., emits hydrocyanic acid.[960]

This acid is consequently widely diffused throughout the vegetable kingdom. Yet amygdalin has thus far only been isolated from a few plants belonging to the genus Prunus or its near allies.[961] In all other plants in which hydrocyanic acid has been met with, we know nothing as to its origin. Ritthausen and Kreusler (1871) have proved the absence of amygdalin in the seeds of a Vicia, which yield bitter almond oil and hydrocyanic acid. These chemists followed the process which in the case of bitter almonds easily affords amygdalin.

Commerce—See preceding article.

Uses—Bitter almonds are used almost exclusively for the manufacture of Almond Oil, while from the residual cake is distilled Bitter Almond Oil. An emulsion of bitter almonds is sometimes prescribed as a lotion.

Adulteration—The adulteration of bitter almonds with sweet is a frequent source of loss and annoyance to the pressers of almond oil, whose profit largely depends on the amount of volatile oil they are able to extract from the residual cake.

FRUCTUS PRUNI.

Prunes; F. Pruneaux à médecine.

Botanical Origin—Prunus domestica L., var. ζ. Juliana DC.—It is from this tree, which is known as Prunier de St. Julien,[962] that the true Medicinal Prunes of English pharmacy are derived. The tree is largely cultivated in the valley of the Loire in France, especially about Bourgueil, a small town lying between Tours and Angers.

History—The plum-tree (P. domestica L.) from which it is supposed the numerous cultivated varieties have descended, is believed to occur in a truly wild state in Greece, the south-eastern shores of the Black Sea (Lazistan), the Caucasus, and the Elburz range in Northern Persia, from some of which countries it was introduced into Europe long before the Christian era. In the days of Pliny, numerous species of plum were already in cultivation, one of which afforded a fruit having laxative properties.

Dried prunes, especially those taking their name from Damascus (Pruna Damascena), are frequently mentioned in the writings of the Greek physicians, by whom as well as at a later period by the practitioners of the Schola Salernitana, they were much employed.

In the older London pharmacopœias, many sorts of plum are enumerated, but in the reformed editions of 1746, 1788, and 1809, the French Prune (Prunum Gallicum) is specially ordered, its chief use being as an ingredient of the well-known Lenitive Electuary; and this fruit is still held by the grocers to be the legitimate prune. The same variety is regarded in France as the prune of medicine.

Description—The prune in its fresh state is an ovoid drupe of a deep purple hue, not depressed at the insertion of the stalk, and with a scarcely visible suture, and no furrow. The pulp is greenish and rather austere, unless the fruit is very ripe; it does not adhere to the stone. The stone is short (⁷/₁₀ to ⁸/₁₀ of an inch long, ⁵/₁₀ to ⁶/₁₀ broad), broadly rounded at the upper end and slightly mucronulate, narrowed somewhat stalk-like at the lower, and truncate; the ventral suture is broader and thicker than the dorsal.

The fruit is dried partly by solar and partly by fire-heat, that is to say, it is exposed alternately to the heat of an oven and to the open air. Thus prepared, it is about 1¼ inches long, black and shrivelled, but recovers its original size and form by digestion in warm water. The dried pulp or sarcocarp is brown and tough, with an acidulous, saccharine, fruity taste.

Microscopic Structure—The skin of the prune is formed of small, densely packed cells, loaded with a dark solid substance; the pulp consists of larger shrunken cells, containing a brownish amorphous mass which is probably rich in sugar. This latter tissue is traversed by a few thin fibro-vascular bundles, and exhibits here and there crystals of oxalate of calcium. By perchloride of iron, the cell-walls, as well as the contents of the cells, acquire a dingy greenish hue.

Chemical Composition—We are not aware of any analysis having been made of the particular sort of plum under notice, nor that any attempt has been made to discover the source of the medicinal property it is reputed to possess. Some nearly allied varieties have been submitted to analysis in the laboratory of Fresenius, and shown to contain saccharine matters to the extent of 17 to 35 per cent., besides malic acid, and albuminoid and pectic substances.[963]

Uses—The only pharmaceutical preparation of which the pulp of prunes is an ingredient, is Confectio Sennæ, the Electuarium lenitivum of the old pharmacopœias. The fruit stewed and sweetened is often used as a domestic laxative.

Substitute—When French prunes are scarce, a very similar fruit, known in Germany as Zwetschen or Quetschen, is imported as a substitute.[964] It is the produce of a tree which most botanists regard as a form of Prunus domestica L., termed by De Candolle var. Pruneauliana. K. Koch,[965] however, is decidedly of opinion that it is a distinct species, and as such he has revived for it Borkhausen’s name of Prunus œconomica. The tree is widely cultivated in Germany for the sake of its fruit, which is used in the dried state as an article of food, but is not grown in England.

The dried fruit differs slightly from the ordinary prune in being rather larger and more elongated, and having a thicker skin; also in the stone being flatter, narrower, pointed at either end, with the ventral suture much more strongly curved than the dorsal. The fruits seem rather more prone to become covered with a saccharine efflorescence.

CORTEX PRUNI SEROTINÆ.

Cortex Pruni Virginianæ; Wild Black Cherry Bark.

Botanical Origin—Prunus serotina Ehrhart (P. virginiana Miller non Linn., Cerasus serotina DC.)—A shrub or tree, in favourable situations growing to a height of 60 feet, distributed over an immense extent of North America. It is found throughout Canada as far as 62° N. lat., and from Newfoundland and Hudson’s Bay in the east, to the valleys west of the Rocky Mountains.[966] It is also common in the United States.

The tree is often confounded with P. virginiana L., from which, indeed, it seems to be separated by no fixed character, though American botanists hold the two plants as distinct. It is also nearly allied to the well-known P. Padus L. of Europe, the bark of which had formerly a place in the Materia Medica.

History—Experiments on the medicinal value of Wild Cherry Bark were made in America about the end of the last century, at which time the drug was supposed to be useful in intermittent fevers.[967] The bark was introduced into the United States Pharmacopœia in 1820. An elaborate article by Bentley[968] published in 1863 contributed to bring it into notice in this country, but it is still much more employed in America than with us.

Description—The inner bark of the root or branches is said to be the most suitable for medicinal use. That which we have seen is evidently from the latter; it is in flattish or channelled pieces, ⅒ to ¹/₂₀ of an inch in thickness, ½ an inch to 2 inches broad, and seldom exceeding 5 inches in length. From many of the pieces, the outer suberous coat has been shaved off, in which case the whole bark is of a deep cinnamon brown; in others the corky layer remains, exhibiting a polished satiny surface, marked with long transverse scars. The inner surface is finely striated, or minutely fissured and reticulated. The bark breaks easily with a short granular fracture; it is nearly without smell, but if reduced to coarse powder and wetted with water it evolves a pleasant odour of bitter almonds. It has a decided but transient bitter taste.

The bark freshly cut from the stem is quite white, and has a strong odour of bitter almonds and hydrocyanic acid.

Microscopic Structure—The chief mass of the tissue is made up of hard, thick-walled, white cells, the groups of which are separated by a brown fibrous prosenchyme. The liber is crossed in a radial direction by numerous broad medullary rays of the usual structure. The parenchymatous portion is loaded both with very large single crystals, and crystalline tufts of calcium oxalate. There is also an abundance of small starch granules, and brown particles of tannic matters. Thin slices of the bark moistened with perchloride of iron, assume a blackish coloration.

Chemical Composition—The bitterness and odour of the fresh bark depend no doubt on the presence of a substance analogous to amygdalin, which has not yet been examined. Hydrocyanic acid and essential oil are produced when the bark is distilled with water, and must be due to the mutual action of that substance alluded to, and some principle of the nature of emulsin. From the fact that an extract of the bark remained bitter although the whole of the essential oil and hydrocyanic acid had been removed, Proctor inferred the existence of another substance to which the tonic properties of the bark are perhaps due.

The fresh bark was found by Perot[969] to yield ½ per mille of hydrocyanic acid in April, 1 per mille in June, and 1·4 in October. The best time for collecting the bark is therefore the autumn.

Uses—In America, wild cherry bark is held in high estimation for its mildly tonic and sedative properties. It is administered most appropriately in the form of cold infusion or syrup, the latter being a strong cold infusion, sweetened; a fluid extract and a dry resinoid extract are also in use. The bark is said to deteriorate by keeping, and should be preferred when recently dried.

FOLIA LAURO-CERASI.

Botanical Origin—Prunus Lauro-cerasus L., a handsome evergreen shrub, growing to the height of 18 or more feet, is a native of the Caucasian provinces of Russia (Mingrelia, Imeritia, Guriel), of the valleys of North-western Asia Minor, and Northern Persia. It has been introduced as a plant of ornament into all the more temperate regions of Europe, and flourishes well in England and other parts, where the winter is not severe and the summer not excessively hot and dry.

History—Pierre Belon, the French naturalist, who travelled in the East between 1546 and 1550, is stated by Clusius[970] to have discovered the cherry-laurel in the neighbourhood of Trebizond. Thirty years later, Clusius himself obtained the plant through the Imperial ambassador at Constantinople, and distributed it from Vienna to the gardens of Germany. Since it is mentioned by Gerarde[971] as a choice garden shrub, it must have been cultivated in England prior to 1597. Ray,[972] who like Gerarde calls the plant Cherry-bay, states that it is not known to possess medicinal properties.

In 1731, Madden of Dublin drew the attention of the Royal Society of London[973] to some cases of poisoning that had occurred by the use of a distilled water of the leaves. This water he states had been for many years in frequent use in Ireland among cooks, for flavouring puddings and creams, and also much in vogue with dram drinkers as an addition to brandy, without any ill effects from it having been noticed. The fatal cases thus brought forward occasioned much investigation, but the true nature of the poison was not understood till pointed out by Schrader in 1803 (see art. Amygdalæ amaræ, p. 248, note 2). Cherry-laurel water, though long used on the Continent, has never been much prescribed in Great Britain, and had no place in any British Pharmacopœia till 1839.

Description—The leaves are alternate, simple, of leathery texture and shining upper surface, 5 to 6 inches long by 1¾ to 2 inches wide, oblong or slightly obovate, attenuated towards either end. The thick leafstalk, scarcely half an inch in length, is prolonged as a stout midrib to the recurved apex. The margin, which is also recurved, is provided with sharp but very short serratures, and glandular teeth, which become more distant towards the base. The under side, which is of a paler colour and dull surface, is marked by 8 or 10 lateral veins, anastomosing towards the edge. Below the lower of these and close to the midrib, are from two to four shallow depressions or glands, which in spring exude a saccharine matter, and soon assume a brownish colour. By the glands with which the teeth of the serratures are provided, a rather resinous substance is secreted.[974]

The fresh leaves are inodorous until they are bruised or torn, when they instantly emit the smell of bitter almond oil and hydrocyanic acid. When chewed they taste rough, aromatic and bitter.

Microscopic Structure—The upper surface of the leaf is constituted of thin cuticle and the epidermis made up of large, nearly cubic cells. The middle layer of the interior tissue exhibits densely packed small cells, whereas the prevailing part of the whole tissue is formed of larger, loose cells. Most of them are loaded with chlorophyll; some enclose crystals of oxalate of calcium.

Chemical Composition—The leaves when cut to pieces and submitted to distillation with water, yield Bitter Almond Oil and Hydrocyanic Acid, produced by the decomposition of Laurocerasin. This is an amorphous yellowish substance isolated by Lehmann (1874) in Dragendorff’s laboratory. He extracted the leaves with boiling alcohol, and purified the liquid by gently warming it with hydroxide of lead. From the liquid, crude laurocerasin was precipitated on addition of ether; it was again dissolved repeatedly in alcohol and precipitated by ether. The yield of the leaves is about 1⅓ per cent. Laurocerasin is readily soluble in water, the solution deviates the plane of polarization to the left, yet not to the same amount as amygdalin. The molecule of laurocerasin, C₄₀H₆₇NO₃₀, would appear to include those of amygdalin, C₂₀H₂₇NO₁₁, amygdalic acid, C₂₀H₂₆O₁₂ and 7 OH₂.

The proportion of hydrocyanic acid in the distilled water of the leaves has been the subject of many researches. Among the later are those of Broeker (1867), who distilled a given weight of the leaves grown in Holland under precisely similar circumstances, in each month of the year. The results proved that the product obtained during the winter and early spring was weaker in the acid in the proportion of 17 to 24, 28, or 30, the strongest water being that distilled in July and August. This chemist found that a stronger product was got when the leaves were chopped fine, than when they were used whole. According to Christison,[975] the buds and very young leaves yield ten times as much essential oil as the leaves one year old. We have ascertained that leaves collected in January when they were thoroughly frozen yielded a distillate containing about ten times less of hydrocyanic acid than in summer. The product obtained from the leaves collected in January, but previously dried for several days at 100° C. (212° F.), still proved to contain both essential oil and hydrocyanic acid.

The unwounded leaves of the cherry-laurel in vigorous vegetation have been shown by our friend Prof. Schaer, not to evolve naturally a trace of hydrocyanic acid, though they yield it on the slightest puncture. We are ignorant of the mode of distribution in the living tissue of the laurocerasin, and of the substances causing its decomposition, and how these two bodies are packed so as to prevent the slightest mutual reaction. The leaves may be even dried at 100° C. and powdered without the evolution of any odour of hydrocyanic acid, but the latter is at once developed by the addition of a little water; on distilling its presence is proved by means of all the usual tests in the first drops of the product.

Besides the substances concerned in the production of the essential oil, the leaves contain sugar which reduces cupric oxide in the cold, a small quantity of an iron-greening tannin, and a fatty or waxy substance.

Schoonbroodt (1868) treated the aqueous extract of the fresh leaves with alcoholic ether, which yielded ¼ per mille of bitter, acicular crystals; these quickly reduced cupric oxide, losing their bitterness.

Bougarel (1877) isolated from the leaves under notice and several others, Phyllinic acid, a crystalline powder melting at 170° C.

Uses—The leaves are only employed for making cherry-laurel water (Aqua Lauro-cerasi), the use of which in England is generally superseded by that of the more definite hydrocyanic acid.

FLORES KOSO.

Flores Brayeræ, Cusso, Kousso, Kosso.

Botanical Origin—Hagenia abyssinica Willd. (Brayera anthelminthica Kunth), a handsome tree growing to a height of 60 feet, found throughout the entire table-land of Abyssinia at an elevation of 3,000 to 8,000 feet above the sea-level.[976] We have never noticed it growing in any botanic garden. The tree[977] is remarkable for its abundant foliage and fine panicles of flowers, and is generally planted about the Abyssinian villages.

History—The celebrated Bruce[978] during his journey to discover the source of the Nile, 1768-1773, found the koso tree in Abyssinia, observed the uses made of it by the natives, and published a figure of it in the narrative of his travels. It was also described in 1799 by Willdenow who called it Hagenia in honour of Dr. K. G. Hagen of Königsberg.

The anthelmintic virtues of koso were investigated by Brayer, a French physician of Constantinople, to which place parcels of the drug are occasionally brought by way of Egypt, and he published a small pamphlet on the subject.[979] Several scattered notices of koso appeared in 1839-41, but no supply of it reached Europe until about 1850, when a Frenchman who had been in Abyssinia obtained a large stock (1,400 lb., it was said), a portion of which he endeavoured to sell in London at 35s. per ounce! The absurd value set upon the drug produced the usual result: large quantities were imported, and the price gradually fell to 3s. or 4s. per lb. Koso was admitted a place in the British Pharmacopœia of 1864.

Description—The flowers grow in broad panicles, 10 to 12 inches in length. They are unisexual, but though male and female occur on the same tree, the latter are chiefly collected. The panicles are either loosely dried, often including a portion of stalk and sometimes a leaf, or they are made into cylindrical rolls, kept in form by transverse ligatures. Very often the panicles arrive quite broken up, and with the flowers in a very fragmentary state. They have a herby, somewhat tea-like smell, and a bitterish acrid taste.

The panicle consists of a zigzag stalk, which with its many branches is clothed with shaggy simple hairs, and also dotted over with minute stalked glands; it is provided at each ramification with a large sheathing bract. At the base of each flower are two or three rounded veiny membranous bracts, between which is the turbinate hairy calyx, having ten sepals arranged in a double series. In the male, the outer series consists of much smaller sepals than the inner; in the female, the outer in the ultimate development become enlarged, obovate and spreading, so that the whole flower measures fully ½ an inch across. In both, the sepals are veiny and leaf-like. The petals are minute and linear, inserted with the stamens in the throat of the calyx. These latter are 10 to 25 in number, with anthers in the female flower, effete. The carpels are two, included in the calycinal tube; and each surmounted by a hairy style. The fruit is an obovate one-seeded nut.

Koso as seen in commerce has a light brown hue, with a reddish tinge in the case of the female flowers, so that panicles of the latter are sometimes distinguished as Red Koso.

Chemical Composition—Wittstein (1840) found in koso, together with the substances common to most vegetables (wax, sugar, and gum), 24 per cent. of tannin, and 6·25 of an acrid bitter resin, which was observed by Harms (1857) to possess acid properties.

The researches of Pavesi (1858), and still more those of Bedall[980] have made us acquainted with the active principle of the drug, which has been named Koussin or Kosin. It may be obtained by mixing the flowers with lime, exhausting them with alcohol and then with water; the solutions mixed, concentrated, and treated with acetic acid, deposit the kosin. We are indebted to Dr. Bedall for a specimen of it, which we find to consist chiefly of an amorphous, resinoid substance, from which we got a few yellow crystals by means of glacial acetic acid.

Mr. Merck favoured us with kosin prepared in his laboratory at Darmstadt. It is a tasteless substance of a yellow colour, forming fine crystals of the rhombic system,—readily soluble in benzol, bisulphide of carbon, chloroform or ether, less freely in glacial acetic acid, and insoluble in water. We found a solution of kosin in 20 parts of chloroform to be destitute of rotatory power. Of alcohol, sp. gr. 0·818, 1000 parts dissolve at 12° C. only 2·3 parts of this kosin. It is abundantly soluble in alkalis, caustic or carbonated, yet has nevertheless no acid reaction, and may be precipitated from these solutions by an acid without having undergone any alteration. It is then however a white amorphous mass, which yields the original yellow crystals by re-solution in boiling alcohol, in which it dissolves readily. The analysis which we have performed of kosin assigns it the formula C₃₁H₃₈O₁₀.

Kosin fuses at 142° C., and remains after cooling an amorphous, transparent yellow mass; but if touched with alcohol, it immediately assumes the form of stellate tufts of crystals. This may be repeated at pleasure, kosin not being altered by cautious fusion.

Kosin is not decomposed by boiling dilute acids. It dissolves in strong sulphuric acid, giving a yellow solution which becomes turbid by the addition of water, white amorphous kosin being thrown down. At the same time a well-marked odour exactly like that of Locust Beans, due to isobutyric acid, CH₃·CH₃·CH·COOH, is evolved. It would thus appear that in all probability kosin is a compound ether of that acid. It is very remarkable that the active principle of fern root, the filicic acid (see Rhizoma Filicis), by decomposition yields butyric acid. If the sulphuric solution of kosin is allowed to stand for a week, it gradually assumes a fine red; and then yields, on addition of much water, an amorphous red mass which after drying is not soluble in bisulphide of carbon, and may thus be purified. We have not succeeded in obtaining this red derivative of kosin in a crystalline state.[981]

In its anthelmintic action, kosin is nearly allied with filicic acid.[982]

Distillation with water separates from the flowers of koso a stearoptene-like oil having the odour of koso, and traces of valerianic and acetic acid. No such body as the Hagenic Acid of Viale and Latini (1852) could be detected by Bedall.

Commerce—Koso is brought to England by way of Aden or Bombay; some appears also to reach Leghorn, probably carried thither direct from Egypt.

Uses—The drug is employed solely as a vermifuge, and is effectual for the expulsion both of Tænia solium and of Bothriocephalus latus. The Abyssinian practice is to administer the flowers in substance in a very ample dose, which is sometimes attended with alarming and even fatal results.

The notion that the action of the drug is partially mechanical and due to the hairs of the plant, prevails in England, and has led to the use of an unstrained infusion of the coarsely powdered flowers. This remedy, from the quantity of branny powder (2 to 4 drachms) that has to be swallowed, is far from agreeable; and as it occasions strong purgation and sometimes vomiting, it is not often prescribed.[983]

The fruit of the koso tree, a small indehiscent achene, is stated by M. Th. von Heuglin[984] to act even more powerful than the flowers; he calls it (or the seed?) Kosála. It would appear that the fruits have been used as an anthelmintic two centuries ago in Abyssinia.[985] Dragendorff (1878) found them to be rich in fatty matters, but devoid of an alkaloid.

PETALA ROSÆ GALLICÆ.