120 DISEASES OF THE RESPIRATORY ORGANS. 



and extract of hyoscyamus, and in rare cases bromide of sodium or 

 chloral hydrate. Expectorants are not of much use in the dog. 

 The laryngeal inflammation so frequently observed in man, namely, 

 Croupal and Diphtheritic Laryngitis, has not been observed in 

 the dog. Esser and Friedberger have each seen a case of partial 

 paralysis of the laryngeal muscles which was accompanied with 

 great difficulty in breathing and roaring sounds during inspira- 

 tion. On post-mortem there was great hypertrophy of the muscles 

 on the posterior side of the larynx, and the atrophied muscle was 

 produced by pressure on the left recurrent nerve. The author has 

 also seen such a case of laborious respiration in a large-sized 

 German bulldog. 



DISEASES OP THE AIR-PASSAGES AND BRONCHIAL 



TUBES. 



Catarrh of the Windpipe and Bronchia ; Bronchitis. 

 {Traohealis and Bronchial Catarrhalis.) 



Etiology. Catarrh of the air- passages and of the bronchia 

 occurs very frequently in young, weakly, debilitated dogs. It 

 sometimes originates primarily, but, as a rule, it occurs as a sec- 

 ondary disease. It is caused by cold, especially by breathing cold 

 air when warm ; and in pet dogs we see it quite often where the 

 animals will lie near the register or an open fire until they are very 

 warm, and then go to the outside door and lie on the floor where 

 the draught can strike on them and get cool very rapidly, and re- 

 peat this a number of times. It is also caused by mechanical or 

 chemical irritations, such as smoke, dust, parasites, strong gases^ 

 or, secondarily, from the extension of inflammations from neigh- " 

 boring organs, as the larynx or lungs, or from defective blood-cir- 

 culation of the lungs produced by weakened heart-action. Catarrh 

 of the trachea and bronchia is very often seen as a complication of 

 distemper, as well as many serious internal diseases, especially in 

 affections of the brain. The latter cause is generally traced to the 

 fact that there is an accumulation of particles of food and secre- 

 tions which collect in the mouth and throat, decompose, and are 

 respired into the trachea and produce an irritation. 



There is no doubt that infectious influences play a certain role in 



