Aloe. U. S., Br. Aloes.
"The inspissated juice of the leaves of Aloe Perryi Baker, yielding Socotrine Aloes; or Aloe vera Linne yielding Curacao Aloes; or of Aloe ferox Miller, yielding Cape Aloes (Pam. Liliaceae)." U. S. "Aloes is the juice that flows from the transversely cut leaves of Aloe chinensis, Baker, Aloe Perryi, Baker, and probably other species of Aloe, evaporated to dryness. Known in commerce as Curacao aloes, Socotrine aloes, or Zanzibar aloes." Br.
Aloe Barbadensis; Aloe Socotrina; Aloes socotrin, ou sucotrin, Fr.; Aloes hepatique des Barbades, Fr.: Socotora oder Socotriniache Aloe, G.; Barbados Aloe, G.; Musebber, Ar.; Acibar Sucotrino, Sp.
The 1890 edition of the U. S. Pharmacopoeia agreed with the British in recognizing as distinct varieties Barbados and Socotrine aloes; but both standards now recognize only the general title of Aloe.
Most plants belonging to the genus Aloe are capable of yielding a bitter juice from which may be prepared an aloes, and there is little doubt that in many cases a commercial aloes exported from one country is the product of several species.
1. A. Perryi, J. G. Baker, Tr. Linn. Soc., xxviii. The true Socotrine aloe plant was first described from specimens sent to Kew Gardens by Wykeham Perry, and was subsequently found by Balfour, of Edinburgh, growing abundantly upon the island of Socotra, especially in the limestone tracts, from the sea level to an altitude of 3000 feet; along with it, but much less abundant, was a dwarf species with spotted leaves. It resembles in its general habit the Barbados aloe, but differs in its shorter leaves, and especially in its flowers, which are arranged in looser racemes on longer pedicels and have the tube much longer than the segments.
The proper aloetic juice was formerly thought to exist in longitudinal vessels beneath the epidermis of the leaves, and readily flows out when these are cut transversely; but, according to E. Robiquet, who made elaborate researches in relation to this drug, these vessels are air ducts, and the juice flows in the intercellular passages between them. The liquid obtained by expression from the parenchyma is mucilaginous, and possessed of little medicinal virtue. After condensation by artificial or natural heat the aloe juice is poured into gourds, more commonly boxes, or into monkey skins, allowed to harden and sent into commerce.
2. A. vera L..This species, which is the source of Curacao Aloes, has a very short, woody stem, and lanceolate embracing leaves, which are first spreading, then ascending, of a glaucous green color, somewhat mottled with darker spots, flat on the upper surface, convex beneath, and armed with hard reddish spines, distant from each other, and perpendicular to the margin. A. vera is a native of Southeastern Europe, Northern Africa, and Madagascar. It is cultivated in Italy, Sicily, Malta, and especially in the West Indies, where it contributes largely to furnish the Barbados aloes.
3. Aloe chinensis Baker..This species was introduced from China into the Dutch Colonies of Curacao by W. Anderson, in 1817. It was described by Haworth from flowerless specimens as a probable variety of A. barbadensis. It is apparently, however, a distinct species and is so recognized in the British Pharmacopoeia. The leaves of A. chinensis are not more than half the length of those in A. barbadensis, and are more or less copiously spotted on the dorsal surface as in A. abyssinica. The flowers have a strong and decidedly unpleasant odor; and occur in loose racemes, the stamens being much shorter than in A. barbadensis. Holmes suggests that A. chinensis may be a native of Africa, Arabia or India. Engler considers that A. chinensis is merely a form related to A. vera. (Baker, in J. L. S.) xviii, p. 161; Holmes, P. J., xxi, p. 205.)
4. A. ferox Miller yields Cape Aloes. It has a simple stem ten to fifteen feet long, four to six inches in diameter; furnished at the top with a dense rosette containing thirty to fifty leaves, which are lanceolate, one and one-half to two feet long, very rigid, with copious prickles on back and face, the margin armed with brown-tipped deltoid or cuspidate prickles one-eighth to one-sixth of an inch long.
According to L. Pappe, Cape aloes of poor quality is obtained from A. africana and A. plicatilis, of Miller;while in Lindley's Flora Medica, A. purpurascens Haworth , A. arborescens Mill., A. Commelyni Willd. , and A. mitriformis are all said to contribute to commercial Cape aloes. Curacao Aloes is apparently produced by the following species: A. vera (L.) Webb, A. vulgaris Lam., A. spicata L., and A. socotrina Lam., all of which have been introduced into the island (see P. J., Jan., Sept., 1890), although E. M. Holmes believes it to be at least in part the product of A. chinensis Baker.
Commercial History and Varieties.—Three chief varieties of aloes have been known in comparatively recent commerce: Socotrine, Barbados or Curacao, and Cape.
SOCOTRINE ALOES.—This variety appears to have been the original aloes, having been produced in the island of Socotra at least as early as the time of Alexander the Great, 333 B.C., who is said to have sent a. commission to investigate its manufacture. Very little, however, of the true Socotrine aloes at the present time comes into the Western markets, the aloes which reaches European commerce from Bombay, Muscat, Aden, and Zanzibar having various botanical and geographical origins. This form of aloes under the title of "Aloes Socotrina" alone is official in the Spanish Pharmacopoeia. It is said to be derived from Aloe vera Mill., A. spicata Thunb., A. ferox L., A. arborescens Mill., and A. lingua-formis L., and other species of aloes.
It is stated that the production of aloes in Arabia was formerly a government monopoly, but that at present it is entirely free to the inhabitants. The leaves, which are cut at any time of year, are allowed to drain into a goat's or sheep's skin, and the gathered juice permitted to evaporate spontaneously. In the course of about one month, when it has become thick and viscid, it is known by the Arabic name of Jayef Gesheeshah; several weeks subsequently, when it has become hard, it is called Jayef Kasahul. Due to its exposure throughout the long process of desiccation, all the varieties of Socotrine aloes contain much foreign matter, which, according to E. R. Squibb, amounts to from 7 to 22 per cent. of the bulk.
The best Socotrine aloes occurs in pieces varying from a dark ruby-red to a yellowish or reddish-brown, more or less semi-transparent, with a glossy surface and a smooth or ragged but not conchoidal fracture, and yielding a bright golden-yellow powder. Its odor is peculiar, almost fragrant, especially developed by breathing upon the aloes, and its bitter, disagreeable taste has a somewhat aromatic tang. The poorest variety of Socotrine aloes, Mocha aloes of the East, is soft, dark, and malodorous. Much of the drug supplied American dealers in recent years has consisted of this variety. Even the finest Socotrine aloes may consist of an orange or yellow colored distinctly fragrant, semi-liquid mass, while the variety known as Zanzibar aloes usually occurs in liver-brown masses, with a dull, waxy fracture, a characteristic odor and a nauseous, bitter taste. The variability of Socotrine aloes probably depends upon not only different methods of preparation but a different origin. Both Zanzibar and true Socotrine Aloes " are opaque even in small splinters, exhibit when examined under the microscope numerous minute crystals embedded in a transparent mass, and impart to nitric acid a reddish or yellowish-brown color." Br., 1900.
CURACAO or BONAIRE ALOES.—This aloes, which is produced in the Dutch West Indian Islands, chiefly in the island of Aruba, appears not to have entered commerce extensively before the early part of the 19th century, but at present constitutes a very large proportion of commercial aloes. It occurs chiefly in three forms; first, an opaque, brittle aloes, showing abundant crystals under the microscope, and sold in gourds usually as Barbados aloes; second, aloes having an appearance like the first variety but sold in cases; third, glossy Curacao or Capey Curacao aloes, which occurs in cases and is glossy and transparent.
It is affirmed that the difference in these varieties of Curacao aloes depends upon the extent of the evaporation by artificial heat, the aloes being dark-colored and opaque when poured into the gourds while still soft; glossy and transparent when allowed to evaporate to dryness over the fire. It is said that the juice is obtained by allowing the leaves to drain into V-shaped troughs, and that it is never evaporated spontaneously.
According to P. van der Wielden, shining Curacao aloes dissolves completely in nitric acid with the production of a red color, while the dull Curacao aloes, giving the same color reaction, fails to entirely dissolve. Kremel gives a method to distinguish Curacao aloes from other kinds by adding to it a little cupric sulphate solution, then some saturated solution of common salt, which makes the color an intense carmine. The reaction is due to cuproaloin. (C. D., 1895, 759.) Curacao aloes is sometimes found in the markets which has been deprived of its aloin; this fraudulent product is then sold as Cape aloes; the odor of the Curacao variety still remains.
BARBADOS ALOES.—This aloes appears to have been brought to London as early as 1693, and to have reached its greatest commercial abundance in the year 1843, when 4227 gourds of it are said to have been exported from Barbados, a gourd containing from twenty to sixty pounds. Occasionally small quantities of Barbados aloes are on the American markets. Most of the Barbados aloes was produced from A. vera, although A. socotrina, A. purpurascens, and A. arborescens are said to have been cultivated.
The method of obtaining Barbados aloes seems to have varied at different periods of time, and possibly in different portions of the island. According to various authors the lower ends of the freshly cut leaves were put into wooden V-shaped troughs, and the exuding juice collected and dried in the sun or boiled in copper pans; again, a decoction of the chopped-up leaves was boiled to the proper consistency; in either case, when the liquor had become so thick that it hardened on cooling, it was poured into calabashes or gourds.
Barbados aloes, as formerly supplied, varied in color from very dark blackish-brown through reddish-brown and liver-colored to orange-brown. It yielded a dull olive-yellow powder, of a disagreeable, even nauseous odor, and it was described in the British Pharmacopoeia as follows: "Fracture either dull and waxy, in which case small splinters are opaque; or smooth and glassy, in which case the splinters are transparent; the opaque variety examined under the microscope exhibits numerous minute crystals embedded in a transparent mass." Br., 1898.
"Mixed with nitric acid, it acquires a red color. Barbados Aloes is not colored, or acquires only a light bluish-green tint, on being mixed with sulphuric acid and blowing the vapor of nitric acid over the mixture (difference from Natal aloes)" U.S.,1890.
According to Marais, Barbados aloes could be distinguished by the fact that its solution in distilled water, 1 to 100,000 parts, yielded on the addition of gold chloride or of tincture of iodine a fine rose color, all other varieties of aloes producing with the reagents named either a feeble color of slow development, or no change of color whatever.
CAPE ALOES.—The general method of collecting Cape aloes is to allow the excised leaves to drain into a sheep's skin, which has been so placed in a hole in the ground as to force the juice to collect in the center. Later this juice is evaporated by artificial heat, and when sufficiently concentrated, poured into boxes or skins. Cape aloes differs from Socotrine aloes, especially in its brilliant conchoidal fracture and peculiar odor, which is strong, but neither nauseous nor aromatic. When freshly broken it has a very dark olive or greenish color approaching to black, presents a smooth, bright, almost glassy surface, and if held up to the light appears translucent at its edges. The small fragments also are semi-transparent, and have a tinge of yellow or red mixed with the deep olive of the opaque mass. The same tinge is sometimes observable in the larger pieces. The powder is of a fine greenish-yellow color, and, being generally more or less sprinkled over the surface of the pieces as they are kept in the shops, gives them a somewhat yellowish appearance. Cape aloes, when quite hard, is very brittle and readily powdered; but in very hot weather it is apt to become somewhat soft and tenacious, and the interior of the pieces is occasionally more or less so even in winter. This variety alone is official in the Swiss, German, and Austrian Pharmacopoeias.
Uganda or crown aloes is a brand of Cape aloes produced by manufacturers who buy the aloe juice from the collectors, allow it to undergo a slight fermentation, and dry it in the sun in wooden troughs. It is sent into commerce in bags containing coarse or fine powder, or chips, and in bricks wrapped in red paper; it has a very bitter, aromatic taste and a strongly aromatic odor. The bricks are of a hepatic brown color, with a resinous fracture, which has a bronzy-gold luster by reflected light. Splinters are translucent, but not garnet-red. With nitric acid it forms a brown solution, gradually changing through dull brownish-yellow to a deep green color.
Natal aloes is a variety coming from Natal, on the southeast coast of Africa, which occurs in irregular pieces, with a fracture much less shining than that of Cape aloes and a totally different color, having a greenish slate hue. It yields a greenish-brown powder, which has the odor of Cape aloes. It is less soluble than Cape aloes, and has a peculiar composition, which will be adverted to under the chemistry of the drug.
Besides the chief varieties of aloes, others are, or have been, known in the market. Hepatic aloes, as well as fetid, caballine or horse aloes, have no proper claim to be considered distinct varieties, being simply inferior aloes of various origins, the first liver-colored, the second blackish and fetid and full of impurities. Jafferabad aloes, supposed to be the same as Mocha aloes (A. J. P., 1881, 175), has been shown to be the product of A. abyssinica Lam., and is said by Shenstone to contain β-barbaloin. (A. J. P., 1883, 92.) Aloes made in India from the A. vera is known as Musambra aloes. It appears to be a very inferior variety, and rarely, If ever, reaches Europe. (P. J., Aug., 1889.) Occasionally aloes is found on the market in which the aloin has been removed. Noyes has reported the presence of pea flour in the powdered drug.
It is evident that the labels under which aloes are largely sold often have little or no connection with the place of production, or with the variety of aloes in the package. This fact has probably come about through the indifference of retail druggists to the variety of the aloes which they are using, an indifference largely due to their common habit of buying aloes in powder. Wilbert (A. J. P., 1903) proposed that aloes should be classified as follows:
Aloes A.—Containing barbaloin; responds to Borntrager's test for emodin, but does not give a distinct red color with nitric acid, or with Klunge's test.
Aloes B.—Containing isobarbaloin with barbaloin; responds to Borntrager's test for emodin, and also has a deep red color with strong nitric acid, or with Klunge's test.
Properties.—The commercial aloes are sometimes divided into two groups:
- Those which are shiny and amorphous, as Cape aloes, and
- Those which are of a dull color and crystalline.
To this latter group most of the other aloes belong. They are also grouped geographically as follows.
- South African aloes, including Cape and Natal.
- East African aloes, including Socotrine, the brown and black Zanzibar aloes and Madagascar aloes.
- The West Indian aloes which includes the Curacao, Barbados and Jamaica varieties.
- The East Indian aloes which includes Jafferabad and Musumbra aloes.
The official description is limited to the three principal varieties, viz., Socotrine, Curacao and Cape aloes and is as follows:
"Socotrine Aloes.—In yellowish-brown to blackish-brown, opaque or smooth and glistening masses; fractured surface somewhat conchoidal; sometimes soft or semi-liquid; odor aromatic or saffron-like, never fetid or putrid; taste nauseous, bitter. Not less than 50 per cent. of Socotrine Aloes is soluble in cold water, the solution being of a yellowish color. The powder is dark brown; when mounted in expressed oil of almond and examined under the microscope, it shows yellowish- to reddish-brown, irregular or angular fragments. On adding nitric acid, it yields a yellowish- to reddish-brown solution.
"Curacao Aloes.—In orange to blackish-brown, opaque masses; fractured surface uneven, waxy, somewhat resinous; odor characteristic but not aromatic as in Socotrine Aloes. Not less than 60 per cent. of Curacao Aloes is soluble in cold water, the solution being of a purplish-red color. The powder is deep reddish-brown; when mounted in expressed oil of almond and examined under the microscope, it shows numerous blackish-brown, irregular, more or less opaque and angular fragments. Upon the addition of nitric acid yields immediately a deep red liquid.
"Cape Aloes.—In reddish-brown or olive-black masses, usually covered with a yellowish powder, or in thin, transparent fragments of a reddish-brown color; fracture smooth and glassy; odor characteristic. Not less than 60 per cent. of Cape Aloes is soluble in cold water, the solution being of a pale yellow color. The powder is greenish-yellow, changing to light brown on aging; when mounted in expressed oil of almond and examined under the microscope, it shows numerous, distinctly angular, bright yellow fragments. Upon the addition of nitric acid, it yields a liquid that is colored reddish-brown, changing to purplish-brown and finally greenish.
The tests which follow apply to Socotrine, Curacao, and Cape Aloes. Aloes contains not more than 10 per cent. of moisture. Add 50 mils of alcohol to 1 Gm. of Aloes, gently heat the mixture and then cool it; a nearly clear solution is obtained (gum and inorganic impurities)* Intimately mix 1 Gm. of Aloes with 10 mils of hot water and dilute 1 mil of this mixture with 100 mils of water; a green fluorescence is produced upon the addition of an aqueous solution of sodium borate (1 in 20). Dilute 1 mil of the original aqueous mixture of Aloes with 100 mils of water, and shake it with 10 mils of benzene; upon separating the benzene solution and adding to it 5 mils of ammonia water, a permanent deep rose color is produced in the lower layer. Aloes yields not more than 4 per cent. of ash." U. S.
The 1914 British Pharmacopoeia gives the following description: "In hard masses, varying in color from yellowish-brown to dark or chocolate-brown. Fractured surface dull, waxy and uniform (Curacao and Zanzibar aloes), or uneven and somewhat porous (Socotrine aloes). Small splinters examined under the microscope exhibit minute crystals embedded in a transparent mass. Characteristic odor; taste nauseous and bitter. The solution obtained by dissolving 0.1 gramme of Aloes in 10 millilitres of boiling water and adding 0.5 gramme of purified borax acquires a green fluorescence. Nitric acid dropped on a little crushed Aloes acquires a reddish-brown color (Socotrine and Zanzibar aloes), or a crimson color (Curacao aloes). Almost entirely soluble in alcohol (60 per cent.). Loss on drying at 100° C. (212° F.) not more than 10 per cent. Ash not more than 5 per cent." Br.
Chemical Properties.—Several distinguished chemists have investigated the nature and composition of aloes. Braconnot found a bitter principle, which he named resino-amer (resinous bitter), and another substance in smaller proportion, which he designated by the name of flea-colored principle. These results were essentially confirmed by Trommsdorff, Bouillon-La-grange, and Vogel. Robiquet obtained a product from aloes which he called aloetin. (For details, reader is referred to 14th ed., U. S. Dispensatory.)
ALOINS.—The bitter substances noticed above, viz., the resino-amer of Braconnot, and the aloetin of Robiquet, probably contain the active principle of aloes, but combined with impurities which render it insusceptible of crystallization. It has been assumed that there exists not one compound, but a set of three closely related compounds, to which the general name of aloins is now given. The first of these, found exclusively in Barbados, aloes, and discovered by T. and H. Smith, is called barbaloin; the second, discovered by Flückiger in Natal aloes, is called nataloin; the third, found by Histed and Flückiger in Socotrine aloes, is called socaloin.
The three aloins, barbaloin, nataloin, and socaloin, are easily distinguished by the following reaction, first noticed by Histed. A drop of nitric acid on a porcelain slab gives, with a few particles of barbaloin or nataloin, a vivid crimson (rapidly fading in the case of barbaloin, but permanent with nataloin unless heat be applied), but produces little effect with socaloin. To distinguish barbaloin from nataloin, test each by adding a minute quantity to a drop or two of sulphuric acid, then allowing the vapor from a rod touched with nitric acid to pass over the surface. Barbaloin (and socaloin) will undergo no change, but nataloin will assume a fine blue. (Pharmacographia, 2d ed., p. 688.) E. von Sommaruga and Egger consider that the three aloins form a homologous series possessing the formulas: barbaloin, C17H20O7; nataloin, C16H18O7; socaloin, C15H16O7, and that they are all derived from anthracene, C14H10. Tilden subsequently assigned a different composition to the aloins: barbaloin and socaloin, each C16H18O7; for nataloin, the formula C25H28O11. He further states that barbaloin and socaloin differ in physical and chemical properties on account of the variation in the molecules of water which are associated with them. Leger assigns to nataloin the formula C23H26O10. The British Pharmacopoeia (1898) assigns to barbaloin the formula C16H16O7,3H2O. Two bases only are recognized now, barbaloin (or simply aloin) and isobarbaloin. According to Leger (P. J., 1902, 21) Cape aloes contains from 5 to 6 per cent. of aloin (barbaloin) without any admixture of the isomeric isobarbaloin. The Barbadoes aloes of English commerce never gave more than 5 per cent. of barbaloin with but minute traces of isobarbaloin, which, however, is always met with in the so-called Barbados aloes of French commerce. Curacao aloes is rich in aloin, containing 10 per cent., of which half is barbaloin and the other half isobarbaloin. Jafferabad aloes is very rich in aloin, yielding 20 per cent., chiefly in the form of isobarbaloin. Socotrine aloes does not contain more than 4 per cent. of aloin, almost wholly barbaloin with a very little isobarbaloin. Since barbaloin is found in almost all varieties, the significance of the prefix "barb" is misleading. The only aloes in which it does not occur is that of Natal.
Hugo Borntrager asserted that one part of aloes in 5000 can be detected in the following manner. A little of the suspected liquid is shaken with about twice its bulk of benzin, which is allowed to separate, decanted, and shaken with a few drops of stronger water of ammonia. On separation the ammonia will be of a clear red color. With solids a tincture should first be made. According to R. H. Groves (P. J., 3d ser., si, 1045), this test will never succeed with a less concentration than 1 part in 250, and with some aloes 1 in 100, and is due to the tannin-like substance of aloes; he also states that extreme care is necessary to have the benzin solution perfectly clear. (P. J., 1885, p. 633. For Hager's quantitative method for determining the percentage of aloin in aloes, see A. J. P., 1885, p. 237.
R. A. Cripps and T. S. Dymond have given the testing of aloes a lengthy investigation, and they recommend the following method. Place 1 grain of the substance in a glass mortar standing on white paper, now add 16 drops of strong sulphuric acid and triturate until dissolved, then add 4 drops of nitric acid, sp. gr. 1.42, and then 1 ounce of distilled water. If aloes be present, a color varying from deep orange to crimson will be produced, according to the kind of aloes that has been used; the color is deepened by the addition of .ammonia. The table below is taken from the paper of Bainbridge and Morrow. (P. J., Jan., 1890.) Under the heading of Kew Specimens are given the results obtained with juice of aloes plants grown in Kew Gardens.
|Commercial Specimens.||HNO2.||H2SO4 and vapor of HNO2.||Cripps and Dymond test.||C. and D. test with NH4HO.||Bromine Test.||FeCl2.|
|Hepatic aloes||Reddish-brown.||Nil.||Orange-red.||Intense brownish-red.||Nil.||All varieties of aloes give an olive-green coloration with the above reagent.|
|True Socotrine||Reddish-brown.||Nil.||Orange-red.||Intense brownish-red.||Nil.|
|Commercial Socotrine||Faint crimson.||Nil.||Crimson.||Deep claret.||Nil.|
|Cape||Permanent green after standing a few minutes.||Nil.||Orange-red.||Pale claret.||Nil.|
|Curacao||Evanescent crimson.||Nil.||Crimson.||Intense claret.||Nil.|
|Natal||Permanent crimson.||Deep blue.||Deep crimson.||Intense brownish-red.||Nil.|
|Barbadoes||Crimson soon fading.||Slight bluish-green occasionally.||Crimson.||Deep claret.||Nil.|
|Aloe ferox||Evanescent crimson.||Green.||Pale yellow.||Red.||Violet.|
|Aloe socotrina||Permanent crimson.||Deep blue.||Crimson.||Intense brownish-red.||Deep purplish-red.|
|Aloe vera||Nil.||Slight green.||Nil.|
|Aloe purpurascens||Crimson fading to light red.||Nil.||Violet.|
|Aloe arborescens, var. frutescens||Nil.||Nil.||Nil.|
|Aloe africana||Evanescent red, changing after a few minutes to red.||Nil.||Orange-red.||Pale claret.||Nil.|
Tschirch, of Berne, has published (B. P. G.) 1898, viii, Heft 6) an important communication, in which he showed that emodin, C15H10O5, or trioxymethylanthraquinone, is the purgative principle of the aloins. He succeeded in obtaining emodin in orange-red crystals which melt at 216° C. (420.8° F.). Emodin was found in the aloins obtained from Cape, Barbadoes, and Socotrine Aloes; it is extracted by treating barbaloin with ether, which dissolves out the emodin. Tschirch found that if a liquid extract of aloes be deprived of its resin and aloin, an additional quantity of emodin could be obtained by boiling the liquid extract with diluted sulphuric acid, thus pointing to the fact that emodin may be produced through hydrolysis. He also showed that emodin could be obtained from purgative drugs of the same class as aloes: rhubarb, rumex, frangula, cascara, senna, rhamnus catharticus, morinda bark, and parmelia.
Aloes yields its active matter to cold water, and when good is almost wholly dissolved by boiling water; but the inert portion, or apotheme of Berzelius, is deposited as the solution cools. It is also soluble in alcohol, rectified or diluted. Long boiling impairs its purgative properties by oxidizing the aloin and rendering it insoluble. The alkalies, their carbonates, and soap alter in some measure its chemical nature, and render it of easier solution. It is inflammable, swelling up and decrepitating when it burns, and giving out a thick smoke which has the odor of the drug.
Those substances only are incompatible with aloes which alter or precipitate the soluble matter, as the insoluble portion is without action upon the system. Among these is the infusion of galls, which we have found, probably through its tannic acid, to afford a copious precipitate with an aqueous solution of aloes. It is said that such a mixture will keep a long time, even for a period of several months, without moldiness or putrescence, though it becomes ropy.
A method for the detection of aloes in mixtures containing other cathartic drugs, such as rhubarb, cascara, etc., has been described by Mossley (Chem. and Drug., 1913, 915). The method depends upon the precipitation of the oxymethyl anthraquinones, which usually interfere in such identification tests, and the subsequent detection of aloes by the addition of bromine T.S., which precipitates aloin, and the green fluorescence produced with aloes by borax.
Uses.—Aloes was known to the ancients, being cultivated in the island of Socotra as far back as the time of Alexander the Great, and is mentioned in the works of Dioscorides and of Celsus. Its cathartic action is due to a stimulation of peristalsis, especially in the larger bowel, probably the result of a local irritant effect upon the mucous membrane, although there is some evidence that it exercises a specific stimulant effect upon unstriped muscles. As its action is largely limited to the colon it is not to be recommended in those conditions in which it is desirable to clean out the whole alimentary canal, and as its effect is largely the result of local irritation it should be avoided in inflammatory conditions of the intestines. In chronic constipation, however, especially when dependent upon an atonic condition of the lower bowel, it is one of the most useful laxatives that wa possess. Many believe that it possesses a directs tonic action, not only evacuating the bowel of its contents but encouraging a restoration toward normal conditions. The presence of bile in the bowel seems in some way to be essential for the best effects of this drug, and in those cases in which this secretion is lacking it is well to exhibit some preparation of bile in conjunction with the aloes. Soap also appears to enhance the cathartic action of this drug. It was formerly almost universally believed that aloes possessed emmenagogue properties and it was accordingly largely used in the treatment of various forms of amenorrhea. It is, however, extremely doubtful whether it exercises any action upon the pelvic organs which is not attributable to its cathartic effects.
Crude aloes is rarely used in human medicine, but may be given in doses of from two to ten grains (0.13-0.65 Gm.).
Off. Prep.—Extractum Colocynthidis Compositum, U. S. (Br.); Pilulae Aloes, U. S. (Br.); Pilulae Rhei Composites, U. S. (Br.); Tinctura Aloes, U. S.; Tinctura Benzoini Composita, U. S. (Br.), Decoctum Aloes Compositum, Br.; Extractum Aloes, Br.; Pilula Aloes et Asafetidae, Br.; Pilula Aloes et Ferri, Br.; Pilula Aloes et Myrrhae, Br.; Pilula Colocynthidis Composita, Br. (N. F.); Extractum Aloes, N. F.; Pilulae ad Prandium, N. F.; Pilulae Aloes et Asafoetidae, N. F.; Pilulae Aloes et Ferri, N. F.; Pilulae Aloes et Mastiches,N. F.; Pilulae Aloes et Myrrhae, N. F.; Pilulae Aloes et Podophylli Compositae, N. F.; Pilulae Aloes, Hydrargyri et Scammonii Compositae, N. F.; Pilulae Antiperiodicae (from Extract), N. F.; Pilulae Colocynthidis et Hyoscyami, N. F.; Pilulae Ferri, Quininae, Aloes et Nucis Vomicae, N. F.; Pilulae Laxativae Post Partum, N. F.; Pulvis Aloes et Canellae, N. F.; Tinctura Aloes et Myrrhae, N. F.; Tinctura Antiperiodica (from Extract), N. F.; Tinctura Zedoariae Amara, N. F.