456 CATARRH. 



When the disturbing lesion is an abnormal condition of part 

 of the structure of the trachea, as fracture, partial or entire, 

 of certain of the cartilaginous rings, we may occasionally, by 

 judicious operative interference, restore the displaced parts to 

 a position less likely to interfere with the air-current in excited 

 respiration. 



CHAPTER XVI. 



CATARRH — CORYZA — COMMOX COLD. 



I. Acute Catarrh. 



Before entering upon the detailed consideration of the affec- 

 tions of the respiratory organs, it will be of advantage to 

 examine cursorily the condition so common all over the 

 country, and affecting horses however located and managed, 

 commonly recognised by the term ' catarrh,' or a ' cold.' 



This might in some respects, considering the very extensive 

 involvement of many organs and functions, be regarded as a 

 general diseased condition. We prefer, however, to look upon 

 it more particularly as associated with those organs where its 

 most characteristic lesions are encountered. 



Definition. — Tlte term catarrh, ivhich has been used to identify 

 this most common affection, is ordinarily understood to indi- 

 cate an inflammatory condition of the lining membrane of 

 the nasal chambers, of the posterior nasal structures and upper 

 portions of the air-tube. It is attended with a serous and 

 ultimately highly cellular discharge from the nasal chambers, 

 occasionally with cough or sore throat, cond tvith or ivithout 

 fever. 



Causation. — It seems tolerably certain that various conditions 

 are in operation predisposing animals to an attack of cold, 

 such as — (1) Youth, or want of maturity and stabiUty of 

 organization, it being more frequent in horses before than after 

 adult life ; (2) A weak and lax condition of animal tissues, 

 cither the result of an inherent diathesis, or acquired through 



