_a._ _By removing constriction of the Pulmonary Exhalant vessels._
There can be no doubt but that, in certain states of disease, the
exhalants of the lungs, like those of the skin, are affected by a
spasmodic constriction, in consequence of which the usual quantity of
fluid for the lubrication of these parts, is not effused, whence a train
of morbid phenomena arise; this appears to happen in _Pneumonia_,
_Asthma_, and certain other diseases of the pulmonary organs. In order
to remove such a constriction, remedies of the Antispasmodic class may
be exhibited with advantage; nauseating doses of Tartarized Antimony, or
of Ipecacuanha, are likewise calculated to fulfil the same indication,
by an operation analogous to that by which Diaphoresis is produced. If
the term might be allowed we should call such remedies _Pulmonary
Diaphoretics_. It is in this way that Venesection, Blisters, and other
anti-phlogistic remedies, may in certain states of the lungs restore a
healthy excretion from these vessels.
_b._ _By stimulating the Pulmonary Exhalants, by the actual contact of a
medicinal substance._
There certainly appear to be substances which enter the circulation, and
are more peculiarly determined to the pulmonary vessels, since their
odour is to be distinctly recognised in the air that is expired.
_Garlic_ may be adduced as an example of this kind; so penetrating is
its odorous principle, that if it be only applied to the soles of the
feet it may be perceived in the breath. Such substances may stimulate
the exhalant vessels through which they pass, and by this stimulus the
secretion may be increased, and the mucus contained in the follicles
diluted, so as to be poured out in a less viscid form, and consequently
in a state to be more easily brought up by expectoration.
_c._ _By stimulating the top of the trachea, and thereby increasing the
activity of the Exhalant vessels of the lungs, by a species of
contiguous sympathy._
The salutary operation of those various remedies, which are allowed to
pass slowly over the fauces, sufficiently establish the fact which is
here announced. In this manner I apprehend that much benefit may arise
from the use of a _Linctus_, and I am satisfied from experience that
certain cases of hoarseness are to be frequently removed by such an
application of stimulating syrups.
The inhalation of certain vapours will also enable us to make a more
direct application to these parts; as, however, it is my intention to
dedicate a chapter to the consideration of this form of remedy, it is
unnecessary to dwell upon it in this place.
II. OF MEDICINES WHICH DIMINISH THE INORDINATE FLOW OF FLUID INTO THE
LUNGS.
_a._ _By removing the debility of the Exhalants._
It not unfrequently occurs in persons either debilitated by age or
disease, that the exhalant vessels of the lungs lose their tone, and
pour out a larger quantity of fluid than is necessary for the
lubrication of these organs; this is particularly observable in the
disease called _humoral asthma_, and in the catarrh of old persons: if
this excess be restrained by strengthening the tone of the system
generally, or by astringing these vessels in particular, the
expectoration of the remainder will be rendered much more easy.
According to my experience, _sulphate of zinc_ displays considerable
powers in moderating this effusion of fluid, and it appears to produce
this effect by increasing the tone of the exhalant vessels of the lungs;
several medicines also, which are included in the former division of
this classification, may, by stimulating these organs, not only promote
the exhalation when it is too scanty, but repress it when it is too
abundant.
_b._ _By increasing the power of the Absorbents._
In some cases, the mucous inundation may not depend upon any fault in
the exhalants, but upon a torpid state of the pulmonary absorbents: our
remedy for this evil is to be found amongst that class of medicines
which have the power of promoting absorption, as small doses of some
mercurial preparation, _Digitalis_, and perhaps _Nicotiana_, &c.
_c._ _By determining to the skin by a gentle diaphoresis._
It is evident that an increase of the cutaneous exhalation is generally
attended with a relative diminution in the other serous excretions of
body; this is so obvious with respect to our urinary discharge, that
every person must have noticed the variation of its quantity at
different seasons of the year: in like manner the exhalation from the
lungs, although less capable of becoming an object of observation, is
not less affected by the state of the cutaneous discharge; hence
medicines capable of promoting it, are calculated to diminish the
quantity of serous exhalation from the lungs; and it is upon this
principle, that well regulated doses of the compound powder of
Ipecacuan], frequently furnish the oppressed asthmatic with a valuable
resource.
_d._ _By exciting serous discharges from the bowels._
Upon the principle announced in the preceding section, the operation of
a saline cathartic may relieve the pulmonary organs when loaded with a
preternatural accumulation of fluid, and consequently assist
expectoration. On the contrary, if the exhalation be deficient, this
class of remedies may increase pulmonary irritation, and check
expectoration, a fact which coincides with the concurrent testimony of
many able practitioners.