DISEASES OF THE RESPIRATORY ORGANS. 85 



P'inally, roaring is often hereditary in horses with a narrow 

 space between the jaws and thick short neck, with badly set-on 

 head, and such should be rejected for breeding purposes. 



BRONCHITIS. 



Inflammation of the large air tubes within the lungs. It may 

 be looked upon as an extension downward of nasal catarrh or 

 sore-throat, and frequently supervenes on one or the other of 

 these. Otherwise it owns the same general causes with these 

 aifections. It may also attend on influenza, strangles, con- 

 tagious pleuro-pneumonia, distemper in dogs, tuberculosis, and 

 parasitic diseases of the lungs. 



Symptoms. — In tnild cases there are dullness, impaired appetite, 

 hot dry mouth, red membrane of nose, accelerated pulse and 

 breathing, and a cough at first hard, but becoming soft and 

 rattling as discharge is established from the nose. Such may 

 recover in a few days without treatment. 



In severe cases there is dullness, inappetence, hot dry mouth, 

 increased temperature, rapid pulse, laboured breathing, with 

 loud blowing sounds over the lower end of the windpipe and 

 behind the middle of the shoulder-blade. The cough is dry, 

 hard, sonorous, and painful (barking), often recurring in fits, 

 and seeming to come from the depth of the chest. Percussion 

 detects no change of resonance at any part of the chest, as in 

 pneumonia. The membrane of the nose has a dark red or 

 violet hue, varying in proportion to the general implication of 

 the bronchial tubes, and especially the smaller ones, and there 

 is drowsiness and drooping of the head in the same ratio. 



From the second to the fourth day a whitish discharge sets 

 in from the nose, the cough becomes soft and rattling, the noise 

 over the windpipe and behind the shoulder-blade less harsh and 

 blowing, but with a slight rattle from bursting bubbles, and the 

 symptoms of fever abate. From this time improvement dates, 

 and recovery may be complete in two or three weeks. 



