HYDROTHORAX. 141 
ble. The last requirement is confirmed. The horse has dropsy of the 
chest, and the termination of the disorder is all but certain. 
The first thing to be done, in these cases, is to draw off the liquid be- 
fore it soddens the pleura and further distresses the already labored 
MAKING THE PRIMARY INCISION FOR TAPPING 
THE CHEST. 
REMOVING THE FLUID IN 
A TROCAR WITH THE STILET UPON IT. HYDROTHORAX, 
breathing. The manner of performing this operation is very simple, 
and the operation itself remarkably safe. A spot near the inferior mar- 
gin of the chest being selected, a small portion of skin, between the 
eighth and ninth ribs, is pulled forward, and then a narrow slit with a 
sharp knife is made upon the place which the skin originally covered. 
A trocar, armed with a stilet, is then inserted into the opening, and so 
much force applied as suffices to propel it onward. The moment all 
resistance ceases, the trocar is within the cavity of the thorax. The 
stilet is then withdrawn, and the water usually flows forth. 
There is in this operation no danger of piercing the lung. The 
trocar must be driven upward and onward, very far and very forcibly, 
to induce such an effect. The lung is protected from all lawful violence 
by the water, on the top of which it floats. 
There is, however, a dispute concerning how much of the fluid should 
be extracted. It is a good rule to take all you can get, or all the con- 
dition of the horse will permit to be abstracted. Do not commence the 
operation with any determinate quantity in your mind. Take all, if the 
horse will suffer so much to be withdrawn; but if the animal, after the 
loss of a quart, shows signs of approaching faintness, withdraw the 
trocar, let the skin fly back, and wait a more favorable opportunity for 
the next attempt. 
In an hour or two the trial can be repeated. Make a new opening 
(for never risk exciting irritation in the original wound, by again thrust- 
