The _Modus Operandi_ of the different elements of each formula is
designated by a KEY LETTER, or _Symbol_, which is printed in a different
type, (thus =B=) and placed in the margin opposite to each. This letter
refers to a corresponding one in the Synopsis, and thereby shews the
division containing an exposition of the principles upon which the
operation of the ingredient is supposed to depend.
Two or more KEY LETTERS denote that the element against which they are
so placed has several modes of operation, whilst the order in which the
letters succeed each other, serves to shew the relative importance of
them.
Where any one of the letters is _small_, _i. e._ not a capital, it
denotes that the operation which it is intended to express is only
_incidental_ to, or subordinate in, the general scheme of the
combination.
When any number of elements are included within a _vinculum_ or bracket,
it is intended to shew that they operate but as one substance, or, that
the virtues of each are not independent of the other; in this case the
KEY LETTER within the bracket expresses upon what principle this unity
depends, whilst that on the exterior shews the action of such a
combination upon the base, or the part which it performs in the general
scheme of the Formula.
Let us exemplify it by a reference to _Formula 78_ which presents us
with a Purgative, in conjunction with a Stimulant. The base is _Aloes_,
which is succeeded by _Scammony_, and _Extract of Rhubarb_; these
substances appear by the bracket, to act in unison, a concurrence which
the interior letter =B= shews to depend upon their being SIMILAR
REMEDIES; the letter also on the exterior shews that its operation upon
the base depends upon the same principle. We next come to powdered
_Capsicum_, and _Oil of Cloves_; these ingredients are also shewn by a
bracket to act in unity, and the letter =B= in the interior, denotes
that it is in consequence of their possessing a similar mode of action,
whilst the letter =G= on the exterior, announces that they act in the
general scheme for the purpose of fulfilling a second indication; at the
same time the smaller letter _e_ informs us that the combination
likewise acts as a _corrector_ of the base.[315]
A SYNOPSIS
OF THE
Principles of Combination,
AS INVESTIGATED IN THE PRECEDING PAGES,
ARRANGED IN A TABULAR FORM
SO AS TO AFFORD THE STUDENT AN EASY
REFERENCE TO THE KEY LETTERS.
_A Synopsis of the Principles of Medicinal Combination._
OBJECT I.
TO PROMOTE THE ACTION OF THE BASIS.
Key Letters.
=A= A.—_By combining the several different forms, or preparations
of the_ SAME SUBSTANCE.
=B= B.—_By combining the Basis with Substances which are of the_
SAME NATURE, _i. e, which are individually capable of
producing the same effects, but with less energy than when
in combination with each other_.
=C= C.—_By combining the Basis with Substances of a_ DIFFERENT
NATURE, _and which do not exert any Chemical influence upon
it, but are found by experience, or inferred by analogy,
to be capable of rendering the stomach, or system, more
susceptible of its action_.
OBJECT II.
TO CORRECT THE OPERATION OF THE BASIS, BY OBVIATING ANY UNPLEASANT
EFFECTS IT MIGHT BE LIKELY TO OCCASION, AND WHICH WOULD PERVERT ITS
INTENDED ACTION, AND DEFEAT THE OBJECT OF ITS EXHIBITION.
=D= A.—_By_ CHEMICALLY _neutralizing, or_ MECHANICALLY
_separating, the offending ingredient_.
=E= B.—_By adding some substance calculated to guard the stomach,
or system against its deleterious effects._
OBJECT III.
TO OBTAIN THE JOINT OPERATION OF TWO, OR MORE MEDICINES.
=F= A.—_By uniting those Medicines which are calculated to produce
the_ SAME ULTIMATE RESULTS, _but by modes of operation
totally different_.
=G= B.—_By combining Medicines which have entirely different
powers, and which are required to obviate different
symptoms, or to answer different indications._
OBJECT IV.
TO OBTAIN A NEW AND ACTIVE REMEDY, NOT AFFORDED BY ANY SINGLE SUBSTANCE.
=H= A.—_By combining Medicines which excite different actions in
the stomach and system, in consequence of which_ NEW, _or_
MODIFIED RESULTS _are produced_.
B.—_By combining substances which have the property of acting_
CHEMICALLY _upon each other; the results of which are_—
=I= a. _The Formation of New Compounds._
=K= b. _The Decomposition of the Original Ingredients, and the
developement of their more active elements._
C.—_By combining Substances, between which no other change is
induced than a diminution, or increase in the_ SOLUBILITY
_of the principles in which their Medicinal virtues reside_.
=L= a. _By the intervention of Substances that act_ CHEMICALLY.
=M= b. _By the addition of Ingredients whose operation is
entirely_ MECHANICAL.
OBJECT V.
TO AFFORD AN ELIGIBLE FORM.
=N= a. _By which the_ EFFICACY _of the Remedy is enhanced_.
=O= b. _By which its_ ASPECT _or_ FLAVOUR _is rendered more
agreeable, or its mode of administration more convenient_.
=P= c. _By which it is_ PRESERVED _from the spontaneous
decomposition to which it is liable_.