Cont'd from Ricinus communis.
OLEUM RICINI, L. E. D.; Castor- Oil.—This may be obtained from the seeds by expression, by decoction, or by the agency of alcohol. The chief part, if not the whole of the oil consumed in England, whether imported or extracted in England, is procured by expression.
Soubeiran [Nouveau Traite de Pharmacie.] considers all processes in which heat is employed as objectionable, as a quantity of fatty acids is produced which renders the oil acrid. In America, on the contrary, heat is considered useful by expelling a volatile acrid principle. [United States Dispensatory.] It cannot be doubted but that too high a temperature develops acrid matter. In England, the oil is expressed, either by Bramah's hydraulic press or by the common screw.press, in a room artificially heated. It is purified by rest, decantation, and filtration. It is bleached by exposure to light on the tops of houses.
In Calcutta, it is prepared as follows: The fruit is shelled by women; the seeds are crushed between rollers, then placed in hempen cloths, and pressed in the ordinary screw or hydraulic press. The oil thus procured is afterwards heated with water in a tin boiler until the water boils, by which the mucilage or albumen is separated as a scum. The oil is then strained through flannel and put into canisters. The castor seeds are distinguished according to the country yielding them. Two principal kinds are known, the large and the small nut; the latter yields the most oil. [Private information from an oil-presser of Calcutta.] The best East Indian castor-oil is sold in London as cold drawn.
In the Southern provinces of India, according to Ainslie, [Materia Indica, vol. i. p. 256.] castor-oil is obtained by decoction.
Much of the American castor-oil is prepared by mere expression, rest, and decantation; but the following are the outlines of the process usually employed in the United States by those who prepare it on the large scale. The seeds, cleansed from the dust and fragments of the capsules, are placed in a shallow iron reservoir, where they are submitted to a gentle heat insufficient to scorch or decompose them, and not greater than can be readily borne by the hand. The object of this step is to render the oil sufficiently liquid for easy expression. The seeds are then introduced into a powerful screw-press, and submitted to pressure, by which a whitish oily liquid is obtained, which is boiled with a considerable quantity of water in clean iron boilers, and the impurities skimmed off as they rise to the surface. The water dissolves the mucilage and starch, and the heat coagulates the albumen, which forms a whitish layer between the oil and water. The clear oil is now removed, and boiled with a minute portion of water until aqueous vapour ceases to arise, and till a small portion of the liquid taken out in a phial preserves a perfect transparency when it cools. The effect of this operation is to clarify the oil, and to render it less irritating by driving off the volatile acrid matter. But much care is requisite not to push the heat too far, lest the oil acquire a brownish hue, and an acrid peppery taste similar to the West India medicine. One basket of the seeds yields five or six quarts, or about twenty-five per cent., of the best oil. [United States Dispensatory]
In the West Indies the oil is obtained by decoction; but none of it comes to this country in the way of commerce. In Jamaica, the bruised seeds are boiled with water in an iron pot, and the liquid kept constantly stirred. The oil, which separates, swims on the top, mixed with a white froth, and is skimmed off. The skimmings are heated in a small iron pot, and strained through a cloth. When cold, it is put in jars or bottles for use. [Wright, Med. plants of Jamaica, in Lond. Med. Journ. vol. viii.] The object of the second heating is to dissipate the volatile acrid principle; but if the process be not suspended immediately after the water is driven off, the oil acquires a reddish-brown colour, an acrid flavour and irritating qualities. It is said that the seeds are sometimes roasted to increase the product. By this process also the oil is coloured and rendered acrid.
In Armenia, lho oil is obtained by decoction; in Russia, by expression. [Chemical Gazette, vol. i. p.210, 1843.]
On the continent of Europe, castor-oil is sometimes obtained by the agency of alcohol. The process is more expensive, and the product is inferior.
The oleum ricini alcoholicum, in use in Italy, is apparently an alcoholic extract, composed of 72 per cent. of oil and 28 per cent. of alcohol and water. The dose is from half an ounce to an ounce. [Pharmaceutical Journal, vol. vii. p. 354, 1848.]
Properties.—Castor-oil is a viscid oil, usually of a pale yellow colour, with a slightly nauseous odour and a mild taste. It is lighter than water, its sp. gr. being, according to Saussure, 0.969 at 55° F. When cooled down to about 0°, it congeals into a transparent yellow mass. By exposure to the air it becomes rancid, thick, and ultimately congeals, without becoming opaque; and hence it is called a drying oil. When heated to a little more than 500° F. it begins to decompose.
Solubility.—Castor-oil is remarkable for its ready solubility in alcohol. Strictly speaking, castor-oil and alcohol exercise a mutual solvent action on each other. When they are shaken together, an homogeneous transparent mixture is obtained. Rectified spirit of wine [According to Stoltze, benzoic acid augments the solubility of castor-oil in spirit containing 75 per cent. of alcohol; that is, in spirit whose sp. gr. is 0.860. Camphor has a similar influence.] may be substituted frequently with a similar result; but with some samples of genuine oil the mixture does not become clear until heat is applied; and moreover by standing a separation takes place into two strata, an upper spirituous one holding oil in solution, and an inferior oleaginous one containing spirit. In one experiment, 65 vols. of oil and 65 vols. of rectified spirit were mixed, and by shaking a transparent uniform mixture was obtained: after several weeks a separation had taken place: the upper stratum measured 12 vols., the lower one 118 vols. Of three samples of genuine oil, one English, a second West Indian, and the third East Indian, I find the English to be the most, and the East Indian the least soluble in rectified spirit.—I find that castor-oil enables other fixed oils (olive, nut, lard, and other oils) to dissolve in alcohol. Thus, if one vol. of olive oil, 2 vols, of castor-oil, and 2 vols, of rectified spirit be mixed and heated, a transparent homogeneous solution is obtained.—Ether readily dissolves castor-oil.
Varieties.—In the London market there are chiefly three sorts of castor-oil; namely, the oil expressed in London from imported seeds, East Indian oil, and the American. West Indian and Australian oils are rarely to be met with.
1. English Castor-Oil.—By this is meant castor-oil drawn in England from imported seeds. It differs somewhat from the imported oil. I am informed that it never bleaches so completely by exposure to light as the East Indian oil. This is usually ascribed to the seeds having suffered some change before they are pressed. But something is probably due to the mode of preparation: in England the oil is not heated in boiling water, as it is in Calcutta.
2. East Indian Castor-Oil is the principal kind employed in this country. It is imported from Bombay and Calcutta. It is an oil of exceedingly good quality (both with respect to colour and taste), and is obtained at a very low price. It is procured from Ricinus communis and R. lividus. I am informed that occasionally it solidifies by keeping.
3. American or United States Castor-Oil is, for the most part, imported from New York. All the samples which I have examined have been of very fine quality, and, in my opinion, had a less unpleasant flavour than the East Indian variety. Our druggists object to it, on the ground of its depositing a white substance (margaritine) in cold weather—a circumstance which has led some persons to imagine it had been mixed with some other fixed oil (lard oleine?).
4. West Indian Castor-Oil.—For an authentic specimen of this oil I am indebted to Mr. Spencer, of Lamb's Conduit Street, who received it some years since from the wife of the Governor of the Island of Tobago, on whose estate it was procured. Its colour is that of golden brown sherry.
5. Australian Castor-Oil.—Of this I have seen but one sample, which was dark coloured.
Commerce.—Castor-oil is imported in casks, barrels, hogsheads, and duppers. The latter are made, as I am informed, of gelatin (prepared by boiling the cuttings of skin) moulded in earthen moulds. In this country the oil is purified by decantation and filtration, and is bleached by exposure to solar light on the tops of houses.
Composition.—The following is the ultimate composition of castor-oil, according to the analyses of Saussure and Ure:—
The proximate principles have not been accurately determined. From Bussy and Lecanu's [Journ. de Pharm, t. xiii. p. 57, 1827.] researches we may infer that castor-oil contains three fats, each composed of oxide of glyceryle and a fatty acid. But according to the more recent investigations of Saalmuller, [Annal. d. Chem. u. Pharm. Bd. lxiv. S. 108, 1848; also The Chem. Gaz. vol. vi. p. 74, 1848.] there can be but two fats in this oil. In addition to these fats there is probably a small proportion of an acrid resin. The following table, therefore, represents the
Presumed Composition or Castor-Oil.
1. Ricinoleine.—This has not been isolated. It is the constituent of castor-oil which by saponification yields oxide of glyceryle and a liquid acid, the ricinoleic acid, C38H35O 5. Bussy and Lecanu regard this acid as a mixture of two acids, which they term ricinic and elaïodic acids.
2. Margaritine; or Ricino-stearine.—This is a solid, white crystalline fat which separates from castor-oil in cold weather. By saponification it yields oxide of glyceryle and a solid crystallizable fatty acid called marguritic acid, which in its melting point (165° F) and composition exhibits a great resemblance to stearic acid, C68H68O7. But with a margaritic acid obtained from another sample of castor-oil, he found the composition to approach more to that of palmitic acid, C32H32O4.
According to Lecanu and Bussy, margaritic acid constitutes only 0.002 of the products of saponification of castor-oil: it follows, therefore, that the proportion of margaritine in the oil must be small. But it is probable that the quantity is variable, and that the differences observed in the action of alcohol in the different specimens of castor-oil depend on variations in the relative proportions of the margaritine and ricinoleine.
3. Acrid Resin?—Some years since, Soubeiran [Journ. de Pharm, t. xv. n. 507. 1829.] obtained from castor-oil by a complicated process what he supposed to be a soft resinous oil, but which was evidently a complex product. To this he in part ascribed the purgative qualities of castor-oil.
Products of decomposition.—By saponification and distillation castor-oil yields certain peculiar products by which it is characterized.
Products of Saponification.
100 Parts of Castor-Oil yielded
1. Fatty acids (viz. ricinic, elalodic, and margaritic acids) . . . 94
2. Glycerine . . . 8
Total . . . 102
Products of Distillation.
(Average of Two Experiments:)
1. Distilled liquid . . . 33.5
(b.) Acetic acid.
(c.) Acroleine (a small quantity).
(e.) Ricinic, elaïodic, and oenanthylic acids.
2. Solid residuum . . . 63.0
3. Loss (inflammable gas) . . . 3.5
Castor-oil . . . 100.00
1. Oenanthol.—Described by Bussy and Lecanu as volatile oil; but more recently by Bussy [Ibid. 3me sér. t. viii. p. 321, 1845; also. Chemical Gazette, vol. iii. p. 381, 1815.] as oenanthol. It is a colourless limpid aromatic liquid, whoso formula is C14H14O2. It is scarcely soluble in water, but dissolves in alcohol and ether. It rapidly oxidizes in the air, and becomes oenanthylic acid (C13H13O3,HO). It combines with water, forming a crystalline hydrate, C14H14O2,HO. By the action of nitric acid it yields at a low temperature an isomeric compound called metoenanthol; and at a high temperature, besides oenanthylic and other volatile fatty acids, a volatile oil resembling oil of cassia.
2. Solid residuum of distillation.—Pale, yellow, elastic, spongy, having the consistence of soft new bread, gelatiniform, odourless, tasteless, combustible, solid. It is insoluble in alcohol, ether, and the oils (both fixed and volatile).
By the action of hyponitric acid on castor-oil Boudet obtained a solid odorous fat called palmine, which, by saponification, yielded palmic acid, C34H32O3,HO, and glycerine; and by the action of nitric acid on castor-oil, Mr. Tilley [Memoirs of the Chemical Society, vol. i. p. 1, 1843.] obtained cenanthylic acid.
Adulteration.—Two kinds of frauds have been practised with regard to castor-oil.
One consists in the admixture of a small quantity of croton oil to it, with the view of increasing its activity. This mixture is introduced into gelatine capsules, and sold as concentrated castor-oil. This fraud is a very dangerous one. I have heard of several cases in which very violent and dangerous effects were produced by these capsules on pregnant females.
The other fraud consists in the adulteration of the castor-oil with some bland viscid cheaper oil. I have been informed that the oleine of lard, called lard oil, has been used for this purpose, but I have not been enabled to procure evidence of it. This kind of fraud is said to be detected by alcohol, which dissolves the genuine castor-oil, but not the admixed oil; and accordingly, in the Edinburgh Pharmacopoeia, the test of the purity of the oil is that "it is entirely dissolved by its own volume of alcohol." Unfortunately, however, for this test, castor-oil may be adulterated with 33 per cent. of another fixed oil, and yet be soluble in its own volume of alcohol.
Physiological Effects.—α. On Animals generally castor-oil acts as a laxative or mild purgative. Large animals, as the horse, require a pint or more for a dose; smaller ones need only a few ounces. [Moiroud, Pharm. Vétér. p. 280.] Mr. Youatt, however, declares this oil to be both uncertain and dangerous in the horse. [The Horse, in Library of Useful Knowledge, pp. 212 and 387.]
β. On Man.—Injected into the veins castor-oil gripes and purges, and causes a nauseous oily taste in the mouth: [Dr. E. Hale, in Begin's Traité de Thérapeutique, p. 114.] hence it would appear to have a specific influence over the mucous lining of the alimentary canal. Swallowed to the extent of one or two ounces, it usually acts as a mild but tolerably certain purgative or laxative, without producing any uneasiness in the bowels. "It has this particular advantage," says Dr. Cullen, [Mat. Med] "that it operates sooner after its exhibition than any other purgative I know of, as it commonly operates in two or three hours. It seldom gives any griping, and its operation is generally moderate—to one, two, or three stools only." It not unfrequently occasions nausea, or even vomiting, especially if somewhat rancid; in many cases, I believe, rather from its disgusting flavour than from any positively emetic qualities.
It has been stated by continental writers that castor-oil is most unequal in its action, at one time operating with considerable violence, at another with great mildness; but I have never found it so, nor is it usually considered to be so in this country. I can, however, readily believe that a difference in the mode of its preparation, especially with reference to the heat employed, may materially affect its purgative property.
When castor-oil has been taken by the mouth, it may be frequently recognized in the alvine evacuations; but it presents itself under various forms, "sometimes resembling caseous flakes, or a soap-like scum, floating on the more fluid part of the dejection: occasionally it had been arranged in a form not unlike bunches of grapes, or more nearly of hydatids of a white colour; more generally, however, it is found mixed up with the faeces as a kind of emulsion, and in some few instances it has been discharged under the form of solid tallow-like masses." [Dr Golding Bird, Lond. Med. Gaz. vol. iv. p. 225.] Mr. Brande [Dict. of Mat. Med.] says in one case it was discharged from the bowels in the form of indurated nodules, which were at first regarded as biliary concretions. A remarkable case is mentioned by Dr. Ward, of a woman on whom this oil does not act as a purgative, but exudes from every part of her body. [Lond. Med. Gaz. vol. x. p. 377.]
Uses.—Castor-oil is used to evacuate the contents of the bowels in all cases where we are particularly desirous of avoiding the production of abdominal irritation (especially of the bowels and the urino-genital organs). The principal, or I might say the only objection to its use in these cases, is its nauseous taste. The following are the leading cases in which we employ it:—
1. In inflammatory affections of the alimentary canal, as enteritis, peritonitis, and dysentery, a mild but certain purgative is oftentimes indicated. No substance, I believe, answers the indication better, and few so well, as castor-oil.
2. In obstructions and spasmodic affections of the bowels, as intussusception, ileus, and colic, especially lead colic, this oil is the most effectual evacuant we can employ.
3. After surgical operations about the pelvis or abdomen (for example, lithotomy, and the operation for strangulated hernia), as well as after parturition, it is the best and safest purgative.
4. In inflammatory or spasmodic diseases of the urino-genital organs, inflammation of the kidneys or bladder, calculous affections, gonorrhoea, stricture, &c, castor-oil is a most valuable purgative.
5. In affections of the rectum, especially piles, prolapsus, and stricture, no better evacuant can be employed.
6. As an anthelmintic for tape-worms, castor-oil was first employed by Odier. Arnemann, however, has shown that it possesses no peculiar or specific vermifuge properties.
7. As a purgative for children, it has been used on account of its mildness, but its unpleasant taste is a strong objection to its use.
8. In habitual costiveness, also, it has been recommended. Dr. Cullen observed that, if castor-oil be frequently repeated, the dose might be gradually diminished; so that persons who, in the first instance, required half an ounce or more, afterwards needed only two drachms.
Administration.—The dose of castor-oil for children is one or two teaspoonfuls; for adults, from one to two or three tablespoonfuls. To cover its unpleasant flavour, some take it floating on spirit (especially gin), but which is frequently contra-indicated; others on coffee, or on peppermint or some other aromatic water; or it may be made into an emulsion by the aid of the yolk of egg or mucilage of tragacanth.