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 Pharmacopœia, 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 PHARMACOPŒIA; 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 pharmacopœia
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 pharmacopœias 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
pharmacopœia, 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.