AS TO SOUNDNESS. 157 



5. Diminished area for blood aeration. 



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- 



