inction ; the operation is in both cases the 
gr » from augmentation of dose, or en 
» diaphoresis or sweat is merely the increase of the = 
n, it must arise from increased action of the cutaneous exha- __ 
The same effect may be produced indirectly, by increasing the _ 
ce of the circulation, which acts asa stimulus on the exh 
as diaphoretics seem to act. “ata: 
The saline diaphoretics, as they do not sensibly augment the 
force of the circulation, probably act in the former manner, exerting 
a particular action on the stomach, which is communicated to the 
vessels of the skin, or perhaps being received into the blood, and 
- directly applied to these vessels. 3s ees 
Those diaphoretics, on the contrary, which are termed heating, as 
the aromatic oils and resins, act by directly stimulating the heart — 
and arteries, and increasing the force of the irculatior 
_ _ Diaphoresis is_not, however, the necessary consequence of the 
circulation being increased ; for the surface often remains dry, where 
the pulseis frequent and strong. In this case, a morbid constriction 
_of the cutaneous vessels exists, which opposes a resistance to the im- _ 
petus of the blood. Whatever, therefore relaxes these vessels, will 
favor ‘the production of sweating; and to this mode of operation 
probably is to be ascribed the diaphoresis produced by antimonial 
preparations, or by ipecacucan, and in part the advantage derived 
from the use of warm diluents in promoting sweat. When these 
circumstances, the increase of the force’of the circulation and the © 
relaxation, of the cutaneous vessels, are conjoined, the sweating 
will be still: more copious ; and from this probably arises the superi- _ 
ority of the combination of opium with antimony oripecacuan,toany 
The primary effects of diaphoretics, are to evacuate the water 
na he blood, ant sey the quantity of fluid in the circu- 
te ermine the blood to the surface; to increase 
CttOl = absorbents, and to remove spasmodic constriction 
of the cutaneous vessels, and render the skin moist. 
The first of these effects probably takes place to no great degree, 
as the free use of diluents makes part of the sweatingregimen.. > 
‘The last effect, the changing the state of the vessels on the skin, 
is the most important, considered in a practical point of view, that 
.diaphoretics produce, as on this their efficacy in fever, in which 
rineipally they are employed, ‘depend. PH, ae 
. 
