Qualities. This expressed oil has a yellow colour, a faint odour, and an acrid taste; these qualities however will be found to vary in different samples; but the fact, as Dr. Nimmo[[682]] has justly observed, may be fairly explained, without suspecting the existence of any fraud, by supposing that the seeds have undergone a different degree of torrefaction, in order to separate the oil from the farinaceous part. Chemical Composition. The recent experiments of Dr. Nimmo have very satisfactorily shewn that this oil consists of 45 parts of an Acrid purgative principle, and 55 of a fixed oil resembling that of olives, and not possessed of any cathartic property. The acrid principle appears to reside in a resinous matter soluble in alcohol and sulphuric æther, and in volatile and fixed oils. I have lately repeated some of Dr. Nimmo’s experiments on a recently imported sample of oil, and with similar results. The acrid principle appears to bear a strong analogy to that which I separated from elaterium, and as I gave to this latter principle the term Elatin, it seems to me that we might with much propriety, apply the name Tiglin to the former, especially as it does not appear to possess any of the characters and habitudes of a salifiable basis; at all events the adoption of such a term will obviate the necessity of circumlocution in our descriptions. Solubility. By alcohol the oil undergoes a ready decomposition; the Tiglin is dissolved together with a very minute quantity of the oily part. Ether and oil of turpentine dissolve the whole; a fact which enables us, by digesting the seeds in these menstrua, to obtain the article in as genuine, and certainly in a much more uniform, condition, than by the processes of torrefaction and expression, as practised in India; for this fact we are also indebted to Dr. Nimmo. Med. Uses. As far as I have been able to ascertain the fact, this oil does not appear to produce any effects which cannot be commanded by other drastic purgatives; its value depends upon the facility with which it may be administered; in some cases it is amply sufficient to touch the tongue, in others, a drop or two will be required. In maniacs, and in cases where the administration of bulky medicines is extremely difficult, it would seem to offer a decided advantage.[[683]] Forms of Exhibition. It has been usually given in this country in the proportion of from one to two drops, in the form of pills. Dr. Nimmo’s discovery with respect to the chemical composition of the oil, very naturally suggested to him the mode of administering it in the form of an alcoholic tincture, (Tinctura Tiglii,) and he has found by experience that such a preparation furnishes the means of readily apportioning the dose to the various circumstances of the case; thus he found that in administering a tincture[[684]] in doses equivalent to the number of drops decomposed, the same effects were produced as have been attributed to the entire oil. Adulterations. Much has been said upon the fraudulent admixture of this comparatively expensive article with the cheaper fixed oils; and we believe with much truth; a circumstance which will of necessity prevent the general use of the article; and occasion very different reports with respect to its value and activity. Dr. Nimmo however proposes a method of detecting such adulteration, by a process suggested by the results of his experiments upon its composition, and whose rationalé will be easily understood after the chemical history that has been just presented.
“Let a very light phial be counterpoised in an accurate balance; pour into it 50 grains of the suspected oil, add alcohol (which has been previously digested[[685]] upon olive oil,) agitate them well, pour off the solution and add more alcohol as before, until the dissolved portion is diffused in such a proportion of alcohol that each half drachm measure shall contain equal to one dose of the oil of Tiglium for an adult. By afterwards placing the phial near a fire, to evaporate what remains of the alcohol in the bottle, if the residuum be to that which has been abstracted by the alcohol as 55 to 45, the oil is genuine. If olive, or any other oil little soluble in alcohol, has been employed as the adulterating agent, it is evident that the residuum will be in a larger proportion; but should Castor Oil have been employed for that purpose, the proportion of the residuum will be smaller even than in the genuine medicine.”
TINCTURÆ. L.E.D. Tinctures.
These consist of alcohol, proof spirit, or spirit of greater or less density, holding in solution one or more of those proximate principles of vegetable or animal matter which are soluble in that menstruum, viz; Sugar, resin, extractive, tannin, cinchonia, camphor, volatile oils, morphia, emetin, conein, elatin, tiglin, and several acids. The proper solvent of those bodies, termed gum-resins, appears to be proof spirit. The compilers of the Codex Medicamentarius of Paris, have defined the different degrees of spirituous strength requisite for the full and perfect extraction of the active elements of different bodies with great truth and nicety; thus they direct for these purposes a spirit of three different standards, viz. 36 (Sp. gr. ·837,) 32 (·856) 22, (·915) of Beaumé’s hydrometer; with the first are prepared the resinous tinctures; with the second those wherein the resinous, extractive, or gummy elements, hold nearly an equal place; and with the third those in which the latter predominate. We are moreover indebted to this committee for having set at rest a question which has been long doubtful, whether the addition of alkaline agents increases the extractive powers of the spirit? They have indeed ascertained by experiment, that the reverse not frequently obtains; for instance, they found that a smaller proportion of guaiacum was dissolved by the spirit of ammonia, than by alcohol of the same strength, and that the quantity of matter dissolved from the root of Valerian was the same in both cases. Very active substances, soluble in alcohol, are those which are particularly adapted for tinctures, since they furnish preparations which are efficient in small doses, and very manageable in extemporaneous prescription, such are the tinctures of Opium, Digitalis, Hyoscyamus, Scilla, &c. and from the chemical analysis of Elaterium, there can be no doubt but that a very active and useful tincture of that substance might be introduced into practice; while Dr. Nimmo has very clearly proved that the active matter of the Croton Tiglium may be thus concentrated, see Tiglii Oleum. On the contrary, substances of little activity, except in large doses, are the least adapted for this form of exhibition, as in such cases the solvent will act more powerfully on the living system, than the principles which it may hold in solution, and when continued for any length of time, will lay the foundation of the pernicious custom of dram drinking; such tinctures, however, are not without their value in combination; they sometimes increase the efficacy, and often correct the operation or disguise the flavour, of the medicines with which they may be united; for example, the cathartic tinctures in Formula 70, augment the purgative powers of the combination, at the same time that they correct its unpleasant operation; many other illustrations are presented in the different formulæ, for the explanation of which I must refer the student to the Key Letters. The addition of a tincture has likewise the effect of preserving decoctions and infusions from spontaneous decomposition, the compound tincture of Cardamoms answers such an object in the compound decoction of Aloes. Tinctures are sometimes made with æther, but they are generally more strongly characterised by the nature of the menstruum than by that of the substance dissolved in it; indeed, æther is used in these cases, not to dissolve substances which would resist the action of alcohol and water, but for the sake of its own direct action on the body; thus the Edinburgh pharmacopœia directs an Æthereal Tincture of Aloes, which is more penetrating and stimulant than the alcoholic tinctures; the London College, with the exception of the Aromatic Spirit of Æther, does not recognise any preparation of this nature: I have already alluded to the Æthereal Tincture of Digitalis of the French Codex, than which nothing can be more injudicious, for the digitalis does not amount to more than 1
70th part of the tincture, and must therefore be entirely counteracted by the stimulant effects of the menstruum. The same objection cannot be urged against the æthereal tinctures of Castor, Musk, and Amber, since in these cases, the subject and the menstruum concur in their mode of operation.
Tinctures derive their names from the substances which impart activity to them, and as the medicinal history of each substance is detailed under its proper head, it will be unnecessary to dwell at any length upon the individual virtues of these tinctures.
1. Prepared with Rectified Spirit.
Tinctura Assafœtidæ. L.D. Dose, fʒss to fʒj.
—— Benzoes Comp. L.E.D. Balsamum Traumaticum, P.L. 1745. This is a combination of Benzoin, Storax, and Tolu, with aloes; it is regarded as a stimulating expectorant, and has been used in chronic catarrh and confirmed asthma, but it is now very rarely employed, except as an application to wounds and languid ulcers. It is sold under the name of Friar’s Balsam; and with respect to the use of this preparation as a Styptic, the public have fallen into a serious error; fresh wounds it must necessarily injure, not only by its stimulating qualities, but by the separation of the resins which take place on its intermixture with the blood; these form a substance, which absolutely prevents what is most desirable in such case,—the sides of the wound coming in contact and uniting by the first intention. Dose. As an internal remedy from fʒss to fʒij, triturated with yelk of egg, or mucilage, to suspend it in water.
Tinctura Castorei. L.E. Dose, ♏︎xx to fʒij. See Form 20, 23, 25, 76, 97, 136.
Tinctura Castorei Composita. E. This is much more active than the preceding tincture, as it contains assafœtida, and its menstruum is ammoniated alcohol. Dose ♏︎xv to fʒj.