13 



SECTION VI. 



DISEASES OF THE AIR-PASSAGES. 



CATARRH, SIMPLE NASAL GLEET 



FEBRILE COUGH 



CHRONIC ROARING 



LARYNGITIS BRONCHOCELE 



CHRONIC POLYPUS NASI 



MALIGNANT EPISTAXIS 



The conduits for the transmission of air into and out of 

 the lungs are, the chambers of the nose_, the larynx, and the 

 windpipe and its ramifications, the bronchial tubes: altogether, 

 these parts are comprised uuder the appellation of the air- 

 passages. Similar parts, similarly related, constitute the air- 

 passages in man ; but between man and horse there is this 

 difference — that the one is able to respire through his mouth 

 as well as his nose, while the other can breathe but through 

 his nose alone : the communication between the cavity of the 

 mouth and the passage to the windpipe being occluded by the 

 soft palate, which in the horse is of extraordinary dimensions. 

 To this fact, familiar as it is, I should say by no means suf- 

 ficient importance had been attached in the consideration of 

 the pathology of the air-passages. In consequence of the 

 absence of any other outlet and entrance for the air, the nasal 

 passages in the horse are made large and capacious, and from 

 the circumstance of all the air respired having to pass through 

 them, these passages necessarily become mpre under the 

 influence of the aerial current — more obnoxious to any efflu- 

 via contained in that current — than the same parts are in 

 man. Hence it is that catarrhal afiections in the horse ordi- 

 narily have their seat in the chambers of the nose, and not 

 in the mouth, or so often in the throat as well, as in man ; 

 hence it is, also, that glanders is (or rather used to be) a 

 common disease in the former, while in man, unless it happen 

 from inoculation, the disorder is unknown/ 



' A case has presented itself of late, in which it is said to have had a 

 spontaneous origin. — * Veterinarian,' vol. xxvi, p. 23. 



