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LIVERPOOL VETERINARY MEDICAL ASSOCIATION. 
him, which give alarm to the well-informed practitioner, for these 
symptoms are generally, though not always, an indication that the 
disease has made dangerous, if not fatal progress. While the disease 
progresses, the blood becomes loaded with poisonous materials, which 
produce their malignant effects upon the whole system, and every 
organ in the body participates in the morbid change ; but more 
especially the parenchyma of the lungs for the lining membrane 
of the air-tubes and air-cells having been more or less in a con- 
gested or inflamed state day and night for several days has now 
become thickened. The breathing becomes slightly more accele- 
rated, but not much more so : there is a brownish-yellow dis- 
charge from the nostrils, and a low suppressed grunt is occasionally 
heard. A perceptible increase of languor and dejection takes 
place ; percussion evinces a heavy dead sound, and the respiratory 
murmur may be distinctly heard; these, and other symptoms, tell 
any experienced man the w'hole history of the change which is 
taking place in these vital organs ; morbid action is insidiously 
going on ; the air-cells are becoming more and more pressed together; 
a loss of resiliency supervenes; and interstitial deposit takes place, 
which has a most destructive tendency. This tuberculous deposit 
may be in the capillaries ; the lining membrane of the capillaries 
have been subjected to inflammation more or less severe now for 
many days, has become thickened, and their structure weakened. I 
can easily conceive them becoming accidentally choked up at specific 
points, a clot forms at sundry points in the parenchyma of the 
lungs, a sort of nucleus exudation through the walls of the capil- 
laries takes place, and the minute tissues next to it become 
acted upon by this interruption ; endosmosis and exosmosis is no 
longer possible at these points ; tubercles form, some run into 
tumours, and abscesses follow in consecutive course. The chemical 
affinity binding the elements that form these substances together 
becomes so feeble that it is only necessary to continue to apply the 
exciting agent to ensure molecular or atomic motion being aroused 
and extended throughout the mass ; then comes into play the in- 
timately related process of fermentation, — for bear this in mind, that 
putrefaction and fermentation are not purely chemical processes, 
but physiological, and the chemical effects observable are the accom- 
paniment or results of vital acts. 
Whether this is the true version of this remarkable, almost 
inscrutable process or not, I believe it is a generally admitted theory, 
that pus is separated from the blood by the secreting power of the 
vessels of an inflamed part, which acquires a new mode of action. 
Sir Astley Cooper said in his lectures : “ If I were to hazard a theory 
upon this subject, 1 should say, that pus was composed of the 
constituent parts of the blood slightly changed in their character by 
inflammation.” 
It is true scrofulous abscesses, or chronic suppuration, may have 
an existence without having been preceded by inflammation. Dr. 
Hunter called these “ Collections of extraneous matter.” We may 
have the same thing in irregular strangles. But it is evident that 
