PLEURISY IN THE FIORSE, CATTLE, AND DOGS. 291 
and given in doses of two or three drachms twice in the da}^ 
It is a principle as true in horse practice as in that of the human 
surgeon, that, if you can increase the discharge of the watery 
part of the blood, you indirectly promote absorption. It may 
happen, however, that the system generally may be considerably 
debilitated by the violence or continuance of the disease, and the 
absorbent vessels, among other parts, may share in the debility. 
Well then, you may begin cautiously to give tonics here, and 
begin as soon as the violence of the disease has abated. The 
spirit of nitrous ether is a mild stimulant and a diuretic. Small 
quantities of ginger and gentian may be added to it, while the 
turpentine should not be omitted. 
Paracentesis .—By auscultation and other modes of examina¬ 
tion, we have ascertained the existence of effusion in the chest, 
and that in spite of all our means it is increasing. Is there any 
mechanical way of getting rid of it? Yes; there is one to which 
I would advise you to have recourse as soon as you are assured 
that there is considerable fluid in the chest, and that it is not 
diminishing. The operation of paracentesis or tapping may be 
performed. It is one of the simplest in the world. You will pass 
the side line over the horse, or simply use the twitch, and having 
one of his legs held up, and, counting back from the sternum to 
between the seventh and eighth ribs, you will pass a moderate¬ 
sized trochar into the chest immediately above the cartilages. 
You w’ill not have selected the most dependent situation, but as 
dependent a one as you could with safety select; for you will 
perceive by this thorax, that there was not room between the 
cartilages to have punctured lower: you must have injured 
them in forcing your instrument through, and, what is worse, 
you would have run great hazard of wounding the pericardium, 
for the apex of the heart rests on the sternum. Through this 
aperture, close to the cartilages, you will evacuate the far greater 
part of the fluid. You will withdraw the stilette, and let the 
fluid run through the canula. You will not trouble yourself 
afterwards about the wound; it will heal readily enough; perhaps 
too much so, for, could it be kept open a few days, it might act 
as a very useful drain. It should he attempted early, I have 
said that you should have recourse to the operation as soon as 
you are assured that there is considerable fluid in the chest, for 
you will at least relieve the animal for a w^hile; you will have 
given some time for repose to the overlaboured lungs, and for 
the system, generally, to be recruited. You will evacuate the 
fluid before the habit of morbid exhalation is established—before 
the lungs are too much debilitated by laborious action against 
the pressure of the water, and before their substance is condensed, 
