MATERIA MEDICA. 
duced in the system, from the primary ef- 
fects of sialagogues, are, a change in the 
distribution of tlie fluids circulating through 
these vessels to wliich the action of the 
sialagogue extends, and through the vessels 
in the neighbourhood of these ; a diminu- 
tion of the quantity of circulating fluids in 
general; and a change in tlie state of the 
remaining mass, iildependently of the di- 
minution of quantity. They may be distri- 
buted into topical, as squills, tobacco, pep- 
pers and other aromatics ; and general, as 
mercurial preparations. 
The use of sialagogues may be deter- 
mined as follows : 1. From their effects as 
changing the balance of circulation, whence 
they may be employed to diminish the im- 
petus of the blood against parts morbidly 
affected in the neighbourhood of the sali- 
vary glands ; to diminish the action of the 
vessels when morbidly increased in these 
neighbouring parts ; to promote free circu- 
lation of the blood through the salivary 
glands, when morbidly obstructed there. 
2. From their effects, as producing evacua- 
tion, whence they may be employed to eva- 
cuate morbid accumulations of serum ; to 
produce a thorough change in the fluids of 
the body, when morbidly vitiated. 
These uses may be illustrated from prac- 
tical observations in cases of tooth-ach, 
angina, dropsy, and siphilis. 
The cautions to be observed in the em- 
ployment of sialagogues, as derived from 
their nature, respect chiefly the stimulus 
they occasion to the salivary glands and 
neighbouring parts ; the time required by 
the order of interna for the production 
of evacuation ; the difficulty, perhaps, in 
some cases, the impossibility, of exciting 
salivation by means of the interna ; and 
the debility induced in the system from ex- 
cessive evacuation. The conditions of the 
system chiefly requiring attention in their 
employment, are, old age, constitutions 
habituated to sialagogues; peculiarities in 
constitution, determining the mercury to 
act on other parts than the salivary glands ; 
menstruation ; and pregnancy. Sialagogues 
are contra-indicated where there is an un- 
common determination to the salivary 
glands; preternatural sensibility in them; 
deficient serosity ; and general debility of 
the system. 
9. Of Emollients. 
By emollients are meant medicines which 
have a power of relaxing the living ani- 
mal fibre, independently of mechanical 
VOL. IV. 
action ; they render tlie part to which they 
are immediately applied more soft and flex- 
ible than it was before. They excite a 
peculiar sensation indistinctly referred to 
the part to which they are applied; they 
produce through the rest of the system an 
effect in some degree analogous to tliat 
taking place in the part on which they 
more immediately act. The changes in- 
duced in the system from the primary effects 
of emollients are, a diminution of the power 
of cohesion in various parts of the animal 
body ; a diminution of the tonic power in 
the system ; an increase of the capacity of 
containing vessels in the part on which they 
more particularly act, and in some degree 
m the system in general ; and an increase of 
irritability and sensibility through the en- 
tire frame. 
They may be regarded as humectant, of 
which we have examples in warm water, 
vvarm vapour, and warm baths ; laxative as 
marshmallows, mallows, white lilly root; 
lubricative, as bland oils, suet, hog’s lard ; 
atonic, as opium, foot-bath. 
The curative indications of emollients 
may be collected hence : 1. From their 
producing a change in the state of the 
moving solids. Hence they may be em» 
ployed to restore the natural flexibility to 
parts morbidly rigid ; to diminish a morbid 
increase of tonic power. 2. From their 
producing a change in the state of the con- 
taining vessels. Hence they may be em- 
ployed, to obviate the effects of morbid 
distention; to remove obstructions. These 
indications may be illustrated and con- 
firmed, from practical observations con- 
cerning the effects of this class of medicines 
as employed in cases of contraction, rigi- 
dity and tumor. The cautions to be ob- 
served in the employment of emollients, as 
derived from their nature, chiefly respect 
their influence as acting on the system in 
general; and the effects of a degree of lax- 
ity induced in particular parts, higher than 
is natural to these. The conditions of the 
system which chiefly require attention in 
their employment are, the period of youth; 
delicacy of habit ; and debility. The cir- 
cumstances chiefly to be attended to in the 
necessary regimen, respect the tempera- 
ture and air in which the patient is kept ; 
and the mode of applying the emollient 
The class of emoUients are chiefly contra- 
indicated by the presence of the following 
morbid states : a high degree of morbid 
relaxation in the system in general; and a 
peculiar sensibility of the moving fibres. 
