DISEASES OF EBSPIRATORY ORGANS 153 



ing death from suffocation, or it may pass down the trachea and 

 occlude the bronchial tubes. 



Symptoms.— The first symptoms manifested are sneezing, cough- 

 ing and dyspnea. As the disease progresses the cough becomes very 

 hoarse and croupy. If the condition is not intensive the symptoms 

 continue and the animals become unthrifty and emaciated. In those 

 cases in which the croupous membrane becomes detached and lodges 

 in the larynx, there will be extreme dyspnea and frequently death 

 by suffocation. 



Treatment. — Prevention is far better than treatment ; in fact, there 

 is little that can be done to relieve an affected animal. Ground barley 

 or other grains in which there are quantities of awns should not be 

 used for feed. 



TUMORS 



Laryngeal tumors are rare. However, pedunculated fibromas have 

 been observed, and epithelioma has been reported. 



Trachea 



MALFORMATIONS 



A case occurs occasionally in which the esophagus forms a union 

 with the trachea. Pigs so affected usually die soon after farrowing. 



STENOSIS 



Congenital tracheal stenosis may occur in swine, but is relatively 

 rare. Acquired stenosis is also rare, because of the protection of the 

 trachea from external injuries. 



TRACHEITIS 



This inflammatory disturbance is usually associated with laryn- 

 gitis or bronchitis, and partakes so closely of the nature of these lat- 

 ter affections that further description will not be given. 



TUMORS 



Tracheal tumors are not common in swine, though fibromas and 

 myxomas of the benign tumors have been observed. 



Bronchial Tubes 



The principal malformations of the bronchial tubes consist of an 

 irregularity in the distribution of the branches of those tubes, but 



