AS TO SOUNDNESS. 157 
5. Diminished area for blood aération. 
6. Hypertrophied right heart. 
7. Pulmonary hemorrhage. 
8. Dropsy. 
It is evident that this train of evils will not be pre- 
sented to your notice at these times, but to the fourth 
" degree inclusive you will find them. 
The thickened mucous membrane gives rise to “thick 
wind” and distress in breathing, shown clearly in the 
facial expression, and the long continuance of violent 
_ breathing effort after exertion, from the strictures of the 
tubes giving passage to diminished streams of air. The 
third and fourth degrees render the lungs unable to 
contract, as we have before seen they are wont to do 
when in health. And this, as we have before seen, 
keeps the diaphragm unduly pressed backwards upon 
the bowels, filled as they are with residual gas, which 
causes the animal to pass flatus frequently, and this 
the more after eating, when the area of the residual 
gas is further encroached upon. Then again the chest 
is more or less barrel-shaped and fixed, also from the 
lungs being kept unduly distended, and the ribs being 
pushed outwards and forwards. These are very grave 
defects, and commonly are easily found out. On placing 
your ear against the sides of the chest, in such cases you 
hear a whining sound on expiration. The bronchioles, 
or smaller bronchial tubes, are muscular structures, whose 
nervous supply is apt, through various causes, to occa- 
