810 WEST OF ENGLAND VETERINARY MEDICAL ASSOCIATION. 
must refer to our old pneumogastric nerve, and its recurrent branches, 
but bow it is that one portion of its peripheries is morbidly sensitive and 
the other either partially or wholly paralysed I will leave for you to 
determine. As this action of coughing is always regulated by the power 
of the expiratory muscles, so here, as we might expect, it is suppressed, 
dry, and short. 
Then as to this disease supervening on severe exertion, such a fact no 
one will care to dispute; but that there must be a very strong hereditary 
tendency in an animal to thus take on the disease appears very probable. 
In such cases it is difficult to realise how these symptoms can be so 
readily produced, but, in corroboration of the fact, we have many well- 
authenticated cases of animals becoming so, and on 'post-mortem examina¬ 
tions, within a few days, a large amount of vesicular emphysema has 
been observed on the external surface of the lunsr-structure. In these 
direct rupture of air-cells would appear to be probable, but as regards 
the emphysema, seen after the usual occurrence of the disease, I am of 
opinion that it is due, not to rupture of air-cells, but merely to a dilated 
and flaccid condition of them. We are already aware that the smaller 
bronchocele tubes are increased in calibre on account of the atrophy of 
their investing muscular layer ; they, therefore, in an act of violent 
inspiration, allow alarger volume of air to pass through them towards the 
air-cells than is normally intended. The tender membrane of which 
these latter are composed is unable to withstand the increased pressure, 
and consequently becomes stretched to a greater or less extent. 
This augmented ,aerial force becomes more difficult for the cells to 
withstand, from the proportionately greater pressure produced on their 
walls, due to the expansion of their contents by increased temperature. 
The other post-mortem appearances usually spoken of are that the lungs 
are more pallid and buoyant, and that they become larger. They cannot 
become larger in the living animal because they can but fill the pleural 
cavities, which they at all times in health completely do, but the small 
amount of collapse in them after death causes the apparent difference in 
size, and the contained air necessarily makes them more buoyant, and 
accordingly lighter in colour. 
Referring once more to the emphysema, or probable rupture of air- • 
cells, after suddenly established cases; in conjunction with this, the other 
morbid changes must have occurred as well, because if this pulmonary 
emphysema constituted in itself broken-wind, how can we explain the 
remarkable influence exerted by some drugs in allaying this disease,—the 
sudden disappearance of all symptoms when shot, or tallow has been 
given, or the wonderful improvement following a judicious system of 
diet ? 
I have now exhausted my small stock of information as regards this 
malady of broken wind. Of the two remaining heads—of chronic cough 
and thick wind—I have not much to advance, beyond that the former 
results from irritability of the bronchial peripheries, and the latter from 
some portion of the lung structure being blocked up by previous disease, 
causing a quicker period of respiration, in order to carry on the aerifica¬ 
tion of the vital fluid. 
Some discussion ensued; after which the members sat down to a 
bountiful dinner, and a pleasant evening was spent. 
J. A. COLLINGS, 
Bon, Sec. 
