l, and only manifest in any degree at the end of
three or four days, when it became stationary if the patient was kept at
rest. In a second series the haemorrhage was of the recurrent variety;
these cases differing little in character from those of slight
continuous haemorrhage. In a third, the bleeding was definitely of a
secondary character, corresponding with one of the classes of secondary
haemorrhage described in Chapter IV., and occurring on the eighth or
tenth day from giving way of an imperfectly closed wounded vessel. In
either of the two latter classes the development of the haemothorax often
corresponded with a journey, or with allowing the patient to get up.

The general course of these effusions was towards spontaneous absorption
and recovery. Coagulation of the blood took place early, the fluid serum
separated, and tended to undergo absorption with some rapidity, leaving
a small amount of coagulum at the base, which evidenced its presence for
many weeks by a persistence of a certain degree of dulness on
percussion. Early coagulation, I think, accounted for the usual absence
of gravitation ecchymosis as a sign.

The course to recovery was sometimes broken by signs of slight pleuritic
inflammation, which, as affecting the amount of effusion, will be spoken
of under the heading of symptoms. In some cases the amount of blood was
so great as to necessitate means being taken for its removal; in these a
reaccumulation often took place. Occasionally an empyema followed in
cases thus treated.

The nature of the blood evacuated on tapping varied much. In very early
aspirations unchanged blood was often met with, but clot sometimes made
evacuation difficult and necessitated a second puncture. In the tappings
done at the end of a week or more a dark porter-like fluid was common,
while when suppuration was imminent a brick-red-coloured grumous fluid
replaced normal blood. In the cases where early incision was resorted
to, blood both fluid and in clots was often mixed with a certain
proportion of lymph flakes, perhaps indicating the part taken by
inflammatory reaction to the irritation of the clot in producing the
rise of temperature.

_Symptoms of haemothorax._--In the more severe cases of primary bleeding
the symptoms did not, as a rule, reach their full height until the third
or fourth day after the injury. The patients then often suffered
severely. The pulse and temperature rose, and to general symptoms of
loss