MATERIA MEDICA. 
without exciting this effect in consequence 
of violent agitation or acute pain. Tlie fol- 
lowing are their direct results : tliey accele- 
rate the motion of the blood ; produce free 
circulation through the vessels on the sur- 
face ; and excite a discharge of sweat. The 
changes induced in the system, from the 
more immediate effects of diaphoretics, are, 
a change in the balance of the circulation ; a 
diminution of the quantity of circulating 
fluids ; and a diminution more particularly 
of the serosity. 
Diaphoretics may be regarded as pun- 
gent, of which we have instances in spirit of 
hartshorn, oil of lavender, or amber ; sti- 
mulant, as various preparations of antimony 
and quicksilver, gniacum, contrayerva, and 
snake-root ; antispasmodic, as musk, opium 
and camphor; and diluent, as water and 
whey. Their use and indication may be 
collected, 1. From their changing the mode 
of circulation; whence they may be em- 
ployed, to obviate morbid determination 
taking place to the internal viscera ; to re- 
move various causes obstructing or im- 
peding the natural state of circulation on 
the surface ; to restore the natural discharge 
from the body, which should take place by 
the surface, in those cases where it is mor- 
bidly diminished. 0. From their producing 
evacuation ; whence they may be employed, 
to diminish the quantity of circulating 
fluids, where it is greater than the state of 
the system at the time can admit of ; to 
restore diminished lymphatic absorption, 
and to discharge morbid accumulations of 
serum. These indications may be illustrated 
and confirmed, fiom practical observations 
concerning the effects of diaphoretic medi- 
cines in fever, dysentery, rheumatism, 
dropsy, and herpes. 
The cautions to be observed in the em- 
ployment of diaphoretic medicines, as de- 
rived from their nature, chiefly respect the 
determination they produce to the surface ; 
the acceleration of the motion of the blood, 
which many of them occasion ; the debility 
whidi, in consequence of the discharge, is 
produced in tiie system ; and the effects 
sometimes produced on the vessels of the 
surface themselves, by the free passage of 
the blood through them. The conditions 
of the system, which chiefly require attention 
in their employment, are, the period of in- 
fancy ; lax and debilitated habits ; constitu- 
tions liable to costiveness. 
4. Of Diuretics. 
These are medicines which, from being 
taken internally, augment the flow of urine 
fiom the kidnies, by stimulating its secre- 
tion from the mass of circulating fluids. The 
changes induced in the system from these 
direct effects, are, a change in the balance 
of circulation ; a diminution of the quantity 
of circulating fluids ; but more especially of 
the serosity and of the saline parts of the 
blood ; an increase of absorption by the 
lymphatic ^vessels ; a diminution of the 
quantity of matter discharged by perspira- 
tion ; and an uncommon flow of fluid 
through the urinary passages. 
Diuretics may be divided into such as are 
stimulant, of which we have instances in 
squills, broom, colchicsm, cantliarides ; re- 
frigerant, as sorrel, berberry, vinegar, cream 
of tartar ; and diluent, as water, whey, and 
acidulated waters. Their use and indica- 
tion may be ascertained from the following 
effects : 1. Their producing evacuation ; 
whence they may be employed to remove 
superabundant serosity from the blood ; to 
evacuate morbid accumulations of serum ; 
to remove morbid acrimony from the blood ; 
to diminish the quantity of circulating 
fluids, when too great for the state of the 
system at the .time. 2. From their altering 
the mode of circulation ; whence they may 
be employed, to restore the natural secre- 
tion of urine, when morbidly diminished ; to 
diminish other secretions, when morbidly 
augmented. 3. From their augmenting the 
flow of liquid through the urinary passages ; 
whence they may be employed, to remove 
obstructions in tliese passages, and to wash 
out acrimony from them. These indica- 
tions may be illustrated by an attention to 
the effects of this class of medicines as em- 
ployed in ascites, ictorus, and nephritis. 
5. Of Cathartics. 
These are medicines which, taken in- 
ternallyi, increase the number of stools by 
stimulating the alimentary canal, increasing 
the peristaltic motion of the intestines, and 
promoting the secretion of the fluids which 
constitute alvine evacuations. They may 
be subdivided into the following tribes : — 
stimulant, as jalap, aloes, bitter-apple; 
refrigerant, as Glauber’s salts, sal polyclirest, 
cream of tartar ; astringent, as rhubarb, 
rose-leaves ; and emollient, as manna, mal- 
lows, castor oil. 
The changes induced in the system from 
the primary effects of carthartics, are, the 
evacuation of the contents of the intestines; 
a diminution of the quantity of circulating 
fluids, and, in a particular manner, of the 
