474 DISEASES OF THE BRONCHI. 



vicissitudes of atmospheric conditions mentioned as productive 

 of common catarrh ; direct irritation of the bronchial mucous 

 membrane by various noxious materials ; general blood-conta- 

 mination, as met with in certain specific diseases and unhealthy 

 states of the system ; also we may, in special cases, regard 

 bronchitis as acknowledging an epizootic influence, as seen m 

 some manifestations 9f influenza. 



Modified by causation, locality, and extent, we observe that 

 acute bronchitis presents some special clinical features which, 

 in the horse, may be grouped or comprised under such varieties 

 as-^1. Primary or idiopathic bronchitis, (a) involving the 

 larger air-tubes ; (6) capillary bronchitis, bronchitis extending 

 into the minute tubes. 2. Secondary bronchitis, bronchitis 

 connected luith certain specific and, general diseases and other 

 unhecdthy states of the body. 3. Mechanical bronchitis. 



b. Anatomical Characters. — The obvious after-death appear- 

 ances in the pulmonary structures of horses Avhich die while 

 suffering from bronchitis are variable, although probably less 

 so than the symptoms which they exhibit while alive. In 

 animals of full age, but in the enjoyment of previously vigorous 

 health, which have succumbed to an acute attack of bronchitis, 

 we find the lining membrane of the bronchial tubes, of all sizes, 

 of a rather dark venous colour ; this colouration may be very 

 generally diffused, or it may be distributed in streaks or 

 patches, with rays proceeding from one spot or patch to 

 another. Occasionally the membrane itself, and in its entirety, 

 is turgid and swollen, soft and pulj)y, with more or less of 

 differently coloured tenacious mucus adhering to it, particu- 

 larly in the larger bronchi. The material contained in the 

 tubes in the earlier stages, succeeding the first condition of 

 arrested secretion, is chiefly of a serous character ; the detached 

 and partly developed epithelial cells are loaded with elements 

 simply of a watery character ; it is generally slightly frothy, 

 and in the pharynx and nasal chambers may be coloured from 

 the colouring matter of what food is being taken. When the 

 disease is somewhat more advanced the character of the exu- 

 dation becomes altered, a certain amount of fibrinous material 

 is mingled with the more watery constituents, and fresh cell- 

 elements abound, giving it a tenacious pus-like character. 

 When not examined immediately after death, the lining mem- 



