en of in Chapter IV., and are to be explained on the
theory of absorption of a blood ferment. The secondary rises always
occurred with a fresh effusion, often of blood, occasioning an
extension, which broke down probable light adhesions and exposed a fresh
area of normal pleural membrane to act as a surface for absorption.

It is, of course, manifest that the fever might also be ascribed to the
infection of the clot or serum from without, and in the first cases I
saw I was inclined to take this view, since we had in every case the
primary wounds of chest-wall, and possibly of lung, and in some the
addition of a puncture by an exploring needle between the first and
second rise. After a wider experience, however, I abandoned the
infection theory, as it seemed opposed by the very infrequent sequence
of suppuration. The effect of simple removal of the blood or serum was
also often so striking as to strongly suggest that it alone was
responsible for the fever. Exactly the same result, moreover, followed
evacuation of the interstitial blood effusions already mentioned
elsewhere.

The common course of all the cases of haemothorax was to spontaneous
recovery, the rapidity of the subsidence of the signs depending mainly
on the quantity of the primary haemorrhage, and the occurrence of further
increases. The blood serum tended to collect at the upper limit of the
original blood effusion (as was often proved on tapping), and this was
first absorbed; the clot deposited on the pleural surface and at the
basal part of the cavity was, however, not absorbed with the same
rapidity. In the majority of the patients when they left the hospitals,
at the end of six weeks on an average, some dulness and deficiency of
vesicular murmur always remained, and the clot and the surrounding
surface, irritated by its presence, will, no doubt, be responsible for
permanent adhesions in many cases. That such adhesions do form in the
majority of cases I feel certain, as, although these patients when they
left the hospital were to all intents and purposes apparently well, few
of them could undertake sustained exertion without getting short of
breath, and sometimes suffering from transitory pain, and for this
reason it became customary to invalid them home.

In a small proportion of the cases empyema followed; but I never saw
this in any case that had neither been tapped nor opened, and I saw
only one patient die from a chest wound uncomplicated by other