96 PATHOLOGY. 
Whilft Dr. Cullen’s claffification has been thought too 
diffufe, and Dr. Darwin’s much too contraftedj and 
adapted merely to his own exceptionable fyftem of nofo- 
logy, Dr. Kirby, in his fmall traft, entitled “ Tables of 
the Materia Medica,” has inferted feventeen clafles, which 
are, upon the whole, judicioufly felefted; and his ar¬ 
rangement has been adopted by moft of thofe modern 
■writers who are of opinion that the materia medica are 
fo numerous as to require a methodus. The claflification 
is as follows; and, as hinted before, every clafs is fub- 
divided, as far as poflible, into an animal, a vegetable, 
and a mineral, feftion. 
Clafs I. Emetics. — Emetics are fuch medicines as 
are calculated to excite vomiting, and thus difcharge 
the contents of the ftomach. 
II. Expectorants. —Thofe medicines are called ex¬ 
pectorants, that are employed to promote the excretion 
of pus or mucus from the windpipe and lungs. In ge¬ 
neral they are emetics given in fmaller doles, though 
there are feveral medicines, efpecially fome of the gum- 
refins, that are confidered to aft in this way, without any 
tendency to excite vomiting. 
III. Diaphoretics. —Diaphoretics are thofe remedies 
that are intended to promote, keep up, or reftore, the ex¬ 
cretion of perfpirable matter from the (kin ; and of thefe 
fome act but feebly, and only increafe the infenfibie per- 
fpiration, while others aft more powerfully, and, under 
favourable circumftances, excite fweating. 
IV. Diuretics. —Thefe are fuch medicines as promote 
or increafe the excretion of urine. 
V. Cathartics. —Cathartics are thofe medicines 
which promote or increafe the evacuation of excremen- 
titious matter, or of ferous fluids, from the bowels. 
VI. Emmenagogues. —Medicines which are fuppofed 
to aft on the womb, and to promote the difcharge of the 
menltrual flux ; but it is more than doubted if any drugs 
whatever have that peculiar aftion. 
VII. Errhines. —Thofe medicines are termed errhines 
that are employed to promote an increafed difcharge of 
mucus from the noftrils. 
VIII. Sialagogues.—T hefe are employed either to 
promote an increafed flow of faliva, or to produce fuch an 
aftion on the gums as (hail indicate their having been re¬ 
ceived in fufficient quantity into the circulation. Under 
the former diviiion are ranked feveral vegetable fubftan- 
ces 5 under the latter are included only mercury and its 
preparations. 
IX. Emollients. —The medicines commonly called 
emollients confift either of diluting liquors, formed of 
Ample water; or certain vegetable infufions ; or mucila¬ 
ginous and oily matters that have the mechanical pro¬ 
perty of defending the parts to which they are applied, 
from the aftion of acrimonious fubftances that pafs over 
them, or of foftening and relaxing the fkin and other 
external parts. The firft of thefe are commonly called 
diluents, the fecond demulcents, and the third limply emol¬ 
lients. 
X. Refrigerants. —Under this term are compre¬ 
hended thofe remedies which are employed with a view 
to diminifh the preternaturally increafed heat that takes 
place in the body during fevers and feveral inflammatory 
affeftions. 
XI. Astringents. —Aftringents are defined by Dr. 
Cullen to be fuch fubftances as when applied to the hu¬ 
man body produce a condenfation and contraftion of the 
foft folids, and thereby increafe their denlity and force of 
cohefion. If they are applied to longitudinal fibres, the 
contraftion is made in the length of thefe; but, if applied 
to circular fibres, the diameters of the veflels, or the cavi¬ 
ties which thefe furround, are diminilhed. 
XII. Tonics. —Tonics are thofe medicines w'hich are 
fuited to counteraft debility, or to give ftrength and ener¬ 
gy to the moving fibres. 
XIII. Stimulants. —Moll of the articles of the Ma¬ 
teria Medica might, in an extended fertfe, be called Jliniu- 
lants; but this term is, by the general confent of phyfi- 
cians, reftriftively applied to thofe medicines which pof- 
fefs the power of fuftaining or increafing the vital ener¬ 
gies ; of raifing and invigorating the aftion of the heart 
and arteries ; and of reftoring to the mufcular fibre, when 
affefted with torpor, its loft: fenfibility and power of 
motion. 
XIV. Antispasmodics. —Thofe medicines which have 
been found by experience to put a flop to convulfive mo¬ 
tions, or fpafmodic contraftions of the mufcular fibres, 
are called antifpafmodics. Moft of them are ftimulants, 
fome narcotics, and fome are confidered as fpecific anti¬ 
fpafmodics. 
XV. Narcotics. —This term has been ufually applied 
to thofe remedies which are calculated to relieve pain and 
procure lleep. They have alfo been termed anodynes and 
hypnotics ; and moft of them were formerly ranked in the 
clafs of fedatives. 
XVI. Anthelmintics. —Thofe medicines which are 
employed with a view to expel worms from the bowels, 
are called anthelmintics. 
XVII. Absorbents. —Medicines which are taken in¬ 
wardly for drying-up or abforbing any acid or redundant 
humours in the ftomach or inteftines. They are likewife 
applied outwardly to ulcers or fores, with the fame in¬ 
tention. 
That each of thefe fyftems was framed by their authors 
in confonance with their peculiar and erroneous theo¬ 
ries is a fufficient reafon for their prefent difmiflal. 
Granting, however, that the effefts of the fubftances 
thus claflified were correftly detailed, it is very evident 
that moft of the clafles are eafily refolvable into the clafs 
of Jlimulants ; for fuppofing that any medicines can pro¬ 
duce expeftoration, that procefs can only be accompliftted 
by ftimulating the exhalent veflels of the bronchial ex- 
panfion ; and the fame remark is applicable to molt of the 
other clafles above mentioned. With refpeft to Simu¬ 
lants, the moft proper pathological divifion appears to be 
according to the particular ftruftures on which they 
exert their effefts. Of thefe the moft general are purga¬ 
tives, emetics, diuretics, and diaphoretics ; not to men¬ 
tion emmenagogues and a holt of others, the feparate 
and independent aftion of which does not appear to be 
well known. 
Purgatives. —Many errors have been committed in 
the adminiftration of this ufeful clafs of fubftances. The 
heterogeneous mixtures which have been made of them, 
and their indifcriminate application, fufficiently prove 
that the phyficians of the laft century did not properly 
underftand the ufe of them. To Dr. Hamilton and Mr. 
Abernethy we are indebted for pointing out the general 
and falutary effefts produced by the exhibition of purga¬ 
tives. Thofe a. thors have clearly fliown, that many 
nervous affeftions, and even chronic dileafes of the fe- 
creting and vafcular funftions, may be cured by thefe re¬ 
medies. Dr. Hamilton’s fuccefs in treating febrile and 
hyfteric difeafes has been truly great; and Mr. Aberne¬ 
thy has demonftrated their Angular utility in local dif¬ 
eafes, as obftinate ulcers, See. Accordingly the benefit 
of cathartics is now very generally eftirnated ; and we are 
perhaps in danger of falling into an error quite oppofite 
to our predeceffors, that of placing too much reliance on 
their ufe. 
Sufficient attention however has not been paid to the 
particular aftion of different cathartics. Praftitioners 
have been too much in the habit of preferibing them in- 
difcriminately, without fufficiently alluding to the effefts 
which each drug is capable of producing on the different 
parts and ftruftures of the alimentary canal. Mr. A. 
Carlifle firft diredted the attention of his profellional 
brethren to this point. “ Cathartics,” he obferves, “ ap¬ 
pear to operate in the following ways; viz. either by ex¬ 
citing the periftaltic motion of the inteftines to an unu- 
fual degree, and thereby caufing them to protrude their 
contents more quickly through the alimentary paffage ; 
i or 
