The Public are already in possession of many pharmaceutical compendiums and epitomes of plausible pretensions, composed with the view of directing the practice of the junior, and of relieving the occasional embarrassments of the more experienced practitioner. Nothing is farther from my intention than to disparage their several merits, or to question their claims to professional utility; but in truth and justice it must be confessed that, as far as these works relate to the art of composing scientific prescriptions, their authors have not escaped the too common error of supposing that the reader is already grounded in the first principles of the science; or, to borrow the figurative illustration of a popular writer, that while they are in the ship of science, they forget the disciple cannot arrive without a boat. I am not acquainted with any book that is calculated to furnish such assistance, or which professes to teach the Grammar, and ground-work of this important branch of medical knowledge. Numerous are the works which present us with the detail, but no one with the philosophy of the subject. We have copious catalogues of formal recipes, and many of unexceptionable propriety, but the compilers do not venture to discuss the principles upon which they were constructed, nor do they explain the part which each ingredient is supposed to perform in the general scheme of the formula; they cannot therefore lead to any useful generalization, and the young practitioner, without a beacon that can direct his course in safety, is abandoned to the alternative of two great evils—a feeble and servile routine, on one hand, or a wild and lawless empiricism, on the other. The present volume is an attempt to supply this deficiency: and while I am anxious to ‘catch the ideas which lead from ignorance to knowledge,’ it is not without hope that I may also be able to suggest the means by which our already acquired knowledge may be more widely and usefully extended; and, by offering a collective and arranged view of the objects and resources of medicinal combination, to establish its practice upon the basis of science, and thereby to render its future career of improvement progressive with that of the other branches of medicine; or, to follow up the figurative illustration already introduced, to furnish a boat, which may not only convey the disciple to the ship, but which may also assist in piloting the ship herself from her shallow and treacherous moorings. That the design however of the present work may not be mistaken, it is essential to remark that it is elementary only in reference to the art of prescribing, for it is presumed that the student is already acquainted with the common manipulations of pharmacy, and with the first principles of chemistry. When any allusions are made to the processes of the Pharmacopoeia, they are to be understood as being only supplementary, or as explanatory of their nature, in reference to the application or medicinal powers of the substance in question. The term Pharmacologia, as applied to the present work, may therefore be considered as contradistinctive to that of Pharmacopoeia; for while the latter denotes the processes for preparing, the former comprehends the scientific methods of administering medicinal bodies, and explains the objects and theory of their operation. The articles of the Materia Medica have been arranged in alphabetical order, not only as being that best calculated for reference, but one which, in an elementary work at least, is less likely to mislead, than any arrangement founded on their medicinal powers; for in consequence of the difficulty of discriminating in every case between the primary and secondary effects of a medicine, substances very dissimilar in their nature, have been enlisted into the same artificial group, and when several of such bodies have, from a reliance upon their unity of action, been associated together in a medicinal mixture, it has often happened that, like the armed men of Cadmus, they have opposed and destroyed each other. The object and application of the black marginal letters, to which the name of Key Letters has been given, are fully explained in the First Part of the work, and it is hoped, that the scheme possesses a more substantial claim to notice than that of mere novelty: it will be perceived that in the enumeration of the officinal formulÆ these letters are also occasionally introduced, to express the manner in which the particular substance, under the head of which it stands, operates in the combination. If any apology be necessary for the introduction of the medicinal formulÆ, it may be offered in the words of Quintillian, who very justly observes, “In omnibus fere minus valent prÆcepta quam exempla;” or in the language of Seneca; “Longum est iter per prÆcepta, breve et efficax per exempla.” Under the history of each article, I have endeavoured to concentrate all that is required to be known for its efficacious administration, such as, 1. Its sensible qualities. 2. Its chemical composition, or the constituents in which its medicinal activity resides. 3. Its relative solubility in different menstrua, and the proportions in which it should be mixed, or combined with different bodies, in order to produce suspension, or saturation. 4. The Incompatible Substances; that is to say, those substances which are capable of destroying its properties, or of rendering its flavour or aspect unpleasant or disgusting. 5. The most eligible forms in which it can be exhibited. 6. Its specific doses. 7. Its Medicinal Uses, and Effects. 8. Its Preparations, Officinal as well as Extemporaneous. 9. Its Adulterations. That such information is indispensible for the elegant and successful exhibition of a remedy, must be sufficiently apparent; the injurious changes and modifications which substances undergo when they are improperly combined by the ignorant practitioner, are not as some have supposed imaginary, the mere deliramenta doctrinÆ, or the whimsical suggestions of theoretical refinement, but they are really such as to render their powers unavailing, or to impart a dangerous violence to their operation. “Unda dabit flammas et dabit ignis aquas.”

In the history of the different medicinal preparations, the pharmacopoeia of the London College is the standard to which I have always referred, although it will be perceived that I have frequently availed myself of the resources with which the pharmacopoeias of Edinburgh and Dublin abound. To a knowledge of the numerous adulterations to which each article is so shamefully exposed, too much importance can be scarcely attached; and under this palpable source of medicinal fallacy and failure, may be fairly included those secret and illegitimate deviations from the acknowledged modes of preparation, as laid down in the pharmacopoeia, whether practised as expedients to obtain a lucrative notoriety, or from a conceit of their being improvements upon the ordinary processes; for instance, we have lately heard of a wholesale chemist who professes to supply a syrup of roses of very superior beauty, and who, for this purpose, substitutes the petals of the red (rosa gallica) for those of the damask rose (rosa centifolia); we need not be told, that a preparation of a more exquisite colour may be thus afforded, but allow me to ask if this underhanded substitution be not a manifest act of injustice to the medical practitioner, who, instead of a laxative syrup, receives one which is marked by the opposite character of astringency. These observations will not apply, of course, to those articles which are avowedly prepared by a new process; for in that case the practitioner is enabled to make his election, and either to adopt or refuse them at his discretion. Thus has Mr. Barry applied his ingenious patent apparatus for boiling in vacuo, to the purpose of making Extracts; we might almost say a priori, that the results must be more active than those obtained in the ordinary way, but they must pass the ordeal of experience before they can be admitted into practice. As a brief notice of the most notorious Quack Medicines may be acceptable, the formulÆ for their preparation have been appended in notes, each being placed at the foot of the particular article which constitutes its prominent ingredient; indeed it is essential that the practitioner should be acquainted with their composition, for although he would refuse to superintend the operation of a boasted panacea, it is but too probable that he may be called upon to counteract its baleful influence.

The Historical Introduction, comprehending the substance of the lectures delivered before the Royal College of Physicians of London, from the recently established chair of Materia Medica, has been prefixed to the work, at the desire of several of the auditors; and I confess my readiness to comply with this request, as it enabled me at once to obviate any misconception or unjust representation of those remarks which I felt it my bounden duty to offer to the College.

It will be observed that the work itself is divided into two separate and very distinct parts, the First comprehending the principles of the art of combination,—the Second, the medicinal history, and chemical habitudes of the bodies which are the subjects of such combination. These comprise every legitimate source of instruction, and to the young and industrious student, they are at once the Loom and the Raw Material. Let him therefore abandon those flimsy and ill-adapted textures, that are kept ready fabricated for the service of ignorance and indolence, and by actuating the machinery himself, weave the materials with which he is here presented into the forms and objects that may best fulfil his intentions, and meet the various exigencies of each particular occasion.

“It has been very justly observed that there is a certain maturity of the human mind acquired from generation to generation, in the MASS, as there is in the different stages of life in the INDIVIDUAL man;—What is history when thus philosophically studied, but the faithful record of this progress? pointing out for our instruction the various causes which have retarded or accelerated it in different ages and countries.”