IRISH CENTRAL VETERINARY MEDICAL ASSOCIATION. 687 
I have found perfect casts of the bronchial tubes, when the disease 
has existed for some time, forced out on the ground during a violent 
fit. In this state a horse may remain for months without much 
change, with the exception of the cough, which gradually and 
stealthily alters in its tone and becomes less frequent, the horse 
only giving n, few loud hollow barks at a time, especially after being 
fed or watered, or leaving the stable. 
Auscultation does not detect much, there is a slight but decided 
increased respiratory murmur, but no rale or syble. At the 
entrance of the chest there is a wheezing noise distinctly heard, 
which comes from the large bronchial tubes, or lower part of the 
trachea. During this time the cough varies very much in its 
intensity, some days the patient will not give a cough, while at 
another time it will be a continuous series of fits or single coughs. 
I can only account for such a state to depend on the condition of 
the alimentary canal, constipation always having a tendency to 
induce the paroxysms. 
Dr. Tanner, alluding to chronic bronchitis in the human subject, 
has detected slightly impaired resonance on percussion, especially 
low down posteriorly, while the vesicular murmur is feebly heard, 
and is mingled with rhonchus and sibilus moist crepitation. 
The 'pathology of the disease consists in chronic inflammation of 
the mucous membrane lining the bronchial tubes, which become 
thickened, and secrete, instead of the natural moisture, an unhealthy 
and increased discharge, which is in some parts unable to be 
removed by the ciliated epithelium, and either clogs up the opening, 
which produces a dilation of the tube behind it, or a collapsed state 
of the lobule to which it leads. In the large bronchii the membrane 
becomes thickened and unhealthy, which is due to the irritative 
effect of the morbid secretion, which has to pass over, and gives 
rise to the troublesome irritable cough. This occurs oftenest at the 
bifurcation of the tubes. On dissection the mucous membrane is 
frequently found of a deep red colour, which may, and is often, 
diflused in patches. It is generally of a more livid or violet tint 
than in the acute disease, when it is usually brighter, or verging 
towards brown. Not unfrequently the membrane is free from this, 
and it is sometimes seen whiter than usual; but this is generally in 
cases where there has been a copious discharge. Softening does not 
occur to the extent to which it goes on in inflammation of the 
gastric mucous membrane, but this is due to the peculiar con¬ 
struction and simple state of the membrane itself. 
The terminations of chronic bronchitis are most important, as it 
is the states in which we are oftenest called on to treat our patients. 
The owner generally brings him under your notice as having a 
troublesome cough and shortness of breath ; this state, on inquiry, 
is found to have existed for a couple of months, and we are gene¬ 
rally informed that the cough has been several times cured, but 
come on again. 
From the investigations I have made, I have come to the con¬ 
clusion that we have the following terminations, viz. first, dilation of 
