452 
EXTENSIVE DISEASE OF THE HEART. 
in the way of a correct diagnosis being formed, especially in 
affections either of the heart or its membranes, when compared 
with those of human medicine. The absence of speech, and 
the comparative difficulty in auscultating the region of the 
heart in the horse and similar formed animals, are, perhaps, the 
principal causes of this difficulty. I have met with prac¬ 
titioners who have thought themselves verv clever in dia- 
gnosing such cases, and, indeed, all others ; but I have, never¬ 
theless, often known them to make great mistakes; and I feel 
confident that errors will continue to be made, particularly in 
heart diseases, by the best informed of our profession. If we 
are fortunate in forming a correct diagnosis in these cases, a 
prognosis is easily determined ; for, in my opinion, very few 
cases, even of simple pericarditis, ever survive, and if 
complicated with other diseases of the heart, the prospect of 
a cure is even still more remote. 
If we investigate the pathological changes which take 
place in these affections, we can easily understand how the 
symptoms will not only vary in degree, but how additional 
ones will of necessity be developed in the progress of the 
disease. To illustrate this assertion, let me briefly allude to 
the morbid specimen in question. The parts consisted of a 
small portion of the lungs, the serous and fibrous pericardial 
sac, and the heart. 
The lung gave evidence of the vessels having been 
congested with blood. The outer pleural covering of the 
fibrous sac, with the exception of a slight portion of it, was 
unaffected by disease. The fibrous sac was thickened and 
very much enlarged, which would be inferred from the large 
quantity of fluid it was said to contain. The serous covering 
of the heart was thickly covered with lymph, as was also that 
portion which covers the inner surface of the fibrous sac, but 
to a less extent. The subserous tissue was thickened by a 
deposition of lymph in its structure, and the muscular walls 
of the heart were of a palish, dirty-brown colour, and much 
softer than natural. The lining membrane of the auricles 
and ventricles, the bicuspid and tricuspid, and also the semi¬ 
lunar arterial valves, were free from disease. Such are the patho¬ 
logical changes produced in the parts sent to me. Mr. Fuller 
states that the liver, spleen, ancl kidneys were very much 
engorged with black blood, and that the abdomen contained a 
large quantity of serous fluid. He also states that the thorax 
contained a considerable quantity of dark-coloured fluid. 
Such a condition of the abdominal viscera and character of 
the effused fluid, we should, a priori , expect. They are to 
be viewed as the effects of impeded circulation, and may be 
