126 DISEASES OF THE HORSE. 
Hydrothorax is sometimes difficult to overcome by means of the 
use of medicines alone, when the operation of tapping the chest is 
performed to allow an escape for the accumulated fluid. The opera- 
tion is performed with a combined instrument called the trocar and 
cannula. The puncture is made in the lower part of the chest, in 
the space between the eighth and ninth ribs. Wounding of the 
intercostal artery is avoided by inserting the instrument as near as 
possible to the anterior edge of the rib. If the operation is of 
benefit, it is only so when performed before the strength is lowered 
beyond recovery. The operation merely receives a passing notice 
here, as it is not presumed that the nonprofessional will attempt 
it, although in the hands of the expert it is attended with little 
danger or difficulty. 
We have described here bronchitis, pneumonia, and pleurisy 
mainly as they occur as independent diseases, but it should be remem- 
bered that they merge into each other and may occur together at one 
time. While it is true that much more might have been said in regard 
to the different stages and types of the affections, and also in regard 
to the treatment of each stage and each particular type, the plan 
adopted of advising plain, conservative treatment is considered the 
wisest on account of simplifying as much as possible a subject of 
which the reader is supposed to know very little. 
PLEUROPNEUMONIA. 
This is the state in which an animal is affected with pleurisy and 
pneumonia combined, which is not infrequently the case. At the 
beginning of the attack only one of the affections may be present, but 
the other soon follows. It has already been stated that the pleura is 
closely adherent to the lung. The pleura on this account is frequently 
more or less affected by the spreading of the inflammation from the 
lung tissue. There is a combination of the symptoms of both diseases, 
but to the ordinary observer the symptoms of pleurisy are the most 
obvious. The course of treatment to be pursued differs in no manner 
from that given for the affections when they occur independently. 
The symptoms will be the guide as to the advisability of giving oil 
and laudanum for the pain if the pleurisy is very severe. It should 
not be resorted to unless it is necessary to allay the pain. 
BRONCHO-PLEUROPNEUMONIA. 
This is the term or terms applied when bronchitis, pleurisy, and 
_ pneumonia all exist at once. It is impossible for one who is not an 
expert to diagnose the state with certainty. The apparent symptoms 
are the same as when the animal is affected with pleuropneumonia. 
