Encyclopaedia Britannica, or, a Dictionary of arts, sciences, and miscellaneous literature : enlarged and improved. Illustrated with nearly six hundred engravings > Volume 13, MAT-MIC

MEDICINE.
pra&ice.
Ffbres. full vomillng is tranlitory, and the exercife of vomit-
ting is a debilitating power j and therefore, when the
vomiting does not remove the atony and fpafm very en¬
tirely, it may give oecafion to their recurrence with
greater force. For thefe reafons, after fevers are fully
formed, fome phyficians have thought proper to em¬
ploy emetics in naufeating dofes only. Thefe are ca¬
pable of exciting the adticn of the extreme veffels, and
their operation is more permanent. At the fame time
they often Ihow their power by exciting fome degree of
fweat, and their operation is rendered more fafe by
their commonly producing fome evacuation by ftool.
But naufea continued for any great length of time, is
to molt patients a fenfation highly diftreffing, and al-
molt infufferable.
The emetics chiefly in ufe at prefent are, ipecacu¬
anha and antimony. The former may be employed for
determining to the furface of the body : but, even in
very final! dofes, it fo readily excites vomiting, that it
is with difficulty employed for the purpofe of naufeat¬
ing only 5 and in whatever manner employed, there is
reafon to fufpeft that its effects are lefs permanent,
and lefs powerfully communicated from the ftomach to
the reft of the fyftem, than thofe of antimony. This
laft is therefore generally preferred ; and its prepara¬
tions, feemingly various, may all be reduced to two
heads 5 one comprehending thofe in which the regu-
line part is in a condition to be affed upon by acids,
and therefore on meeting with acids in the ftomach it
becomes adlive •, and another, comprehending thofe
preparations in which the reguline part is already join¬
ed with an acid, rendering it a£live. Of each kind
there are great numbers, but not differing effentially
from one another ; the two moft worthy of notice are,
the ca/x nitrata antimonii, and emetic tartar, or tartrite
of antimony, of the Edinburgh Difpenfatory. Both
thefe are very efficacious medicines ; but the latter
feems preferable, becaufe its dofe is capable of being
better afcertained \ though the former, on account of
its flower operation, may have fome advantages, and in
certain cafes be more efficacious as a purgative and
fudorific.
The calx nitrata antimonii, when firft introduced in¬
to the pharmacopoeia of the Edinburgh college was
fuppofed to be very nearly, if not precifely, the fame
with a medicine which has of late been highly cele¬
brated in the cure of fevers, Dr James’s powder. But
from more accurate obfervations, there is now reafon
to believe that the pulvis antimonialis .of the J-mndon
Pharmacopoeia, formed by the calcination of anti¬
mony with hartfliorn, approaches more nearly to that
celebrated arcanum. But at any rate, the calx anti¬
monii nitrata, the pulvis antimonialis, and James’s
powder, are probably not effentially different from
each other. The two latter, however, have the moft
near refemblance ; and accordingly the Edinburgh col-
lege, in their Pharmacopoeia, have introduced an ar¬
ticle under the title of antimonium calcareo-phofphora-
tum, which they confider as fo much fimilar to James’s
potvder, that they have ufed as a fynonyme for it, the
title of pulvis Jacobi.
The time moft proper for exhibiting thofe medicines
is a little before the acceffion, when that can be cer¬
tainly known. In continued fevers the exacerbations
are not always very obfervable 5 but there is reafon to
believe, that one commonly happens about noon or
foon after it; and that thefe, therefore, are the moft
proper times for exhibiting emetics.
With refpeft to the manner of adminiftration, that
of the calx nitrata is Ample, as the whole of what is
thought a proper dofe may be given at once ; and no
more can be properly given till the next acceffion.
The adminiftration of the emetic tartar is different. It
is to be given in fmall dofes, not fufficient to excite vo¬
miting ; and thefe dofes are to be repeated after fhort
intervals for feveral times, till ficknefs, naufea, and
fome, though not much, vomiting come on. The dif¬
ference of adminiftration muft depend upon the dofe,
and the length of the interval at which it is given. If
it be intended that the medicine ftiould certainly ope¬
rate by ftool, the dofes are made fmall, and the inter¬
vals long. On the contrary, when vomiting is proper,
or when much purging ought to be avoided, and there¬
fore fome vomiting muft be admitted, the dofes are
made larger, and the intervals ftiorter. With refpedt
to both kinds of preparations, the repetition is to be
made at the times of acceffion, but not very often : for
if the firft exhibitions, duly managed, have little effedt,
it is feldom that the after exhibitions have much ; and
it fometimes happ ens that the repeated vomiting, and
efpecially repeated purging, does harm by weakening
the patient.
(2.) 1 he other fet of internal medicines which are
fuppofed ufeful in taking off the fpafm of the extreme
veffels, are thofe named antifpajmodics. But whatever
may be the virtues of fome of them in this way, fuch
is their power of ftimulating at the fame time, that
very few of them can with fafety be adminiftered in
fevers of an inflammatory nature. Almoft the only
one which can with fafety be exhibited in thefe cafes
is camphor •, and the operations of this are by no means
well afcertained. Dr Huxham mentions it as a cor¬
rector of the acrimony of cantharides ; and affures us,
that it very effectually promotes a diaphorefls. But
from the remarks of other practitioners, we have no
juft reafon to fuppofe that it acts perceptibly in a dofe
of five or fix grains, though in 15 or 20 it produces a
particular kind of intoxication.
Secondly, The external means Anted to take off the
fpafm of the extreme veffels, are bliftering and warm
bathing.
1. What are the effects of bliftering fo frequentfy
employed in fevers is not yet agreed among phyfi¬
cians. Dr Cullen is of opinion, that the fmall quan¬
tity of cantharides abforbed from a bliftering plafter,
is not fufficient to change the confiftence of the mafs
of blood; and therefore, that fuch a quantity can nei¬
ther do good by refolving phlogiftic lentor if it exifts,
nor do harm by increafing the diffolution of the blood
arifing from a putrid tendency in it. The effects of
cantharides upon the fluids, therefore, may be entirely
neglected. The inflammation produced by the appli¬
cation of cantharides to the Ikin, affords a certain proof
of th eir ftimulant power : but in many perfons the ef¬
fect of that ftimulus is not confcderable ; in many It is
not communicated to the whole fvftem ; and even when
it does take place in the whole fyftem, it feems to be
taken off very entirely by the effufion and evacuation of
ferum from the bliftered part. It may be concluded,
therefore, that neither much good is to be expected,
E 1 2 nor