Section IV.-HEALTH AND DISEASE-con«m«ec^ 



7. THE ORGANS OF RESPIRATION-Conimweci 



DISEASES OF THE LUNGS 



General Considerations. — Under this general term are included 

 the disorders atiecting the bronchial tubes, the lung tissue itself, and its 

 investing membrane — the pleura. Although the diseases are considered 

 separately and receive special names, they are frequently found to exist 

 together. Nevertheless, it is common to find one particular structure 

 so prominently affected as to warrant the use of a name identifying the 

 disease. A compromise in nomenclature, where two principal structures 

 are at the same time affected, may be found in such terms as broncho- 

 pneumonia, pleuro-pneumonia, &c., at one time in exclusive use by the 

 professions, but now generally understood by the public, who are 

 familiarized in great part with medical terms through reading in the lay 

 press accounts of the illnesses of eminent persons. 



BRONCHITIS 



Definition. — Bronchitis is an intiamed condition of the mucous mem- 

 brane lining the bronchial tubes. 



It may occur as a primary disorder in which the larger bronchi are 

 chiefly involved, or it may follow upon or complicate other diseases. Two 

 forms of the malady are recognized — one sharp and of brief duration, known 

 as acute bronchitis, and the other less severe but protracted, termed 

 chronic. 



Causes. — The predisposing causes are weakness, old age, and damp, 

 cold stables. A previous attack and the exhausting influence of other 

 diseases also increase the liability to a second seizure. Young horses in 

 close stables are more subject to it than others, if we except the worn-out 



/ Vol II. 1 35 



