Unless Opium were a resinous Body, it could not retain its volatile Power, to bear transporting in the Form it does, much less endure to be kept in the Shops with little Loss. The burning of it proves the Truth of this Assertion, and if it were a mucous Gum, or viscous juice, it would not flow by Heat, nor import its Strength to a spirituous, but to an aqueous Menstruum, after the Manner of Gum Arabic. It may be asked here, in Opposition to this, how the Extract from Opium is made, in which Process the Opium, according to the College, is ordered to be dissolved in Water? In Answer to it, I presume, the Water is only an Agent, that prevents the Adustion of the Parts so exposed to intense Heat, which Menstruum, being partly imbibed by the Impurities of the Drug, causes a sufficient Separation, for the resinous Parts to become soft enough to be pressed through a Bolter; by such Management, the fæcæs are entirely separated from the purer Parts, and the Water, though used most cautiously, and in as sparing a Quantity as possible, by the necessary Evaporation, in order to reduce the pure Body to the former Substance, loses more than it gains; and after all, in my Opinion, is not so much to be depended upon, or has so mild an Effect as good Opium; notwithstanding Doctor Jones's Opinion to the to the contrary, and his partial Fondness, in giving the Name Panacea to his Solution in Water.
The College of Physicians have ordered only two Preparations that retain the Name of Opium, wisely considering, that those of the Ancients were so numerous, and so variously combined with other Substances, under the Title of Correctors, that the Bulk in administering them was greatly encreased, and an Inconvenience arose oftentimes to the Patient, who not being able to take the Quantity of the Opiate required, thereby rendered the Effect frequently precarious.
One Preparation, directed by them, is by Solution, as mentioned above, merely to purify it from heterogeneous Particles, and thence called Extractum Thebaicum, or Extract of Opium; the other a Tincture or Re-Solution of that Extract, to be preserved in a fluid State with Wine, in the Proportion of two Ounces to one Pound, with an Addition of Aromatics. This last Preparation, which is in more general Use than the Extract, is commonly known by the Name of Laudanum; though that Epithet was formerly used by Authors for various Preparations of the Drug, with the Appendage of Opiatum, Tartarizatum, &c. to characterise their Differences.
I shall not enlarge upon Opium in a physical Sense, further than is necessary to shew the poisonous Effects of it in over-large Doses, and as such, I confine myself to the Sort within every one's Knowledge, and to be commonly met with in the Shops.
The poisonous Effects of Opium, whether in a solid or fluid State, may be considered in the same Light, as Ebriety from spirituous Liquors; a very small Quantity will overcome a weak Constitution, while a strong one will require much more; nevertheless, a weak Constitution, used to Opium, will bear as much, uninjured, as the strongest, if unaccustomed to the Use of it. In a general Sense, however, even in the most robust, a Dose, exceeding three Grains, may be truly pronounced to be of dangerous and poisonous Consequence; and in some Cases, half that Quantity will prove sufficient. It operates sooner in a liquid, than in a solid Form; in the former, admitting the Doses are too large, in half an Hour, and often in fifteen, or ten Minutes, unless Exercise intervenes; In the latter, in two Hours, sometimes in one, sometimes in half an Hour; the Injury produced by the Liquid, being more sudden and transient, that of the Solid, more slow and lasting.
The Liquid, by a speedy Expansion, is frequently, and almost instantly, rejected by the Stomach, the other not; by which it is easily discoverable, that though the Effects of Opium, in a liquid State, are more immediate, they are sooner counteracted, and more easily overcome; for which Reason, every Vender of Medicines ought to be extreamly cautious to whom he sells this Drug, that it may not be converted to a wrong Use. However it is seldom known that a Person attempts to poison himself with solid Opium, though frequently with the Tincture.
The general Effects of Opium, are as follow, viz. Upon almost immediate taking, the first Symptoms are a Heat and Weight at the Stomach, succeeded by an Extravagance of Spirits, even to violent Laughter, Listlesness of the Limbs, Giddiness, Head-ache, Loss of Memory, dead Look of the Eyes, imperfect Speech, Drowsiness, slow and full Pulse, short and quick Breathing, Nauseas, and an extream florid Complexion. These Symptoms are the common Consequences of Drunkenness, as well as Opium, though not all at the same Time in one and the same Object, the Symptoms varying according to the Strength of the Constitution. The more violent and extream Effects are Itchings of the Skin, Madness, Vertigoes, Vomitings, Hickups, heavy and dead Sleeps, unequal Pulse, Contraction of the Jaw, Convulsions, profuse Sweats, universal Relaxation, Faintings, Coldness of the extreme Parts; and lastly, a cold Breath, a certain Indication of Death.
Before we treat of the Cure of these too violent and, too frequently, fatal Effects, it will be requisite to explain the Cause of this Poison's Power in the Primæ Viæ, or Stomach. First then, let us consider the component Parts, which, when examined by a chemical Analysis, are found to contain a very large Portion of volatile Salt and Spirit; a fœtid; corrosive, and sulphureous Oil; some little of a fixed Salt; and a small Quantity of indolent Earth. Vide Lemery, Mead, Geoffroy, &c.
The Principle of Action Consists of a volatile alkaline Salt, intimately united to, and enveloped in, a corrosive sulphureous Oyl.
The Sensations of the Stomach are most evidently exquisite, by Hunger and Thirst; with which those other Senses of Smelling and Tasting are in immediate Contact and Agency, which the wise Ordination of a supream Hand, for the Preservation of Life, has proportionally distributed through every Part of the Creation, from Man down to the most small and apparently insignificant Insect.