s description of the symptoms it would appear, that there
could be no great difficulty in distinguishing this from other
diseases; yet probably it has sometimes been confounded with asthma,
and very frequently with hydrothorax. Some may think, that there is no
essential difference in the symptoms of these diseases. The
resemblance between them, however, is merely nominal.

The cough in hydrothorax, unlike that which attends organic diseases
of the heart, is short and dry; the dyspnoea constant, and not subject
to violent aggravations. An uneasiness in a horizontal posture attends
it, but no disposition to incurvate the body forward. These are some
of the points, in which these two diseases slightly resemble each
other. Those, in which they totally differ, are still more numerous;
but as most of them have been already mentioned, it is unnecessary to
indicate them here.

It is probable, that the two diseases commonly arise in patients of
opposite physical constitutions; the hydrothorax in subjects of a weak
relaxed fibre; the organic diseases of the heart in a rigid and robust
habit. The subjects of the latter affection, in the cases which have
fallen under my observation, were, with the exception of one or two
instances, persons of ample frame, and vigorous muscularity, and who
had previously enjoyed good health. In nearly all these cases the
collection of water was principally on one side, yet the patients
could lie as easily on the side where there was least fluid, as on the
other; which, in the opinion of most authors, is not the case in
primary hydrothorax. It should also be observed, that, in many of the
cases, there was only a small quantity of water in the chest, and that
in neither of them was there probably sufficient to produce death. May
not primary hydrothorax be much less frequent, than has commonly been
imagined?

Idiopathic dropsy of the pericardium may, perhaps, produce some
symptoms similar to those of organic disease of the heart; but it
appears to be an uncommon disorder, and I have had no opportunity of
observing it. In the fourth case, a remarkable disposition to syncope,
on movement, distinguished the latter periods of the disease, and
might have arisen from the great collection of water in the
pericardial sac.

The causes of this disease may, probably, be whatever violently
increases the actions of the heart. Such causes are very numerous; and
it is therefore not surprising, that organic disea