MICROBIAN BRONCHITIS IN DOGS. 



Causes. Infectious bronchitis is a very common manifestation 

 of distemper in dogs, but apart from this, slight bronchitis and 

 sore throats are particularly liable to be complicated by the 

 serious invasion of the inflamed and debilitated mucosa by 

 microbes which have been living as saprophyte s, it may be out 

 of the body, or it may be on the pituita, mouth, fauces, tonsils, 

 pharynx or larynx, or even on the bronchia themselves. All such 

 conditions as operate in other animals, hurried breathing, sudden 

 inspiration after cough, and paresis of the cilia, etc., are equally 

 effective here in favoring the entrance of the microbes into the 

 lower air passages, and their colonization on and even in the mu- 

 cosa. Once established there the invading microorganisms adapt 

 themselves to the new environment and more readily attack other 

 animals, though these may not have been subjected to the same orig- 

 inal exciting cause. Thus it may start in a dog which has been 

 fatigued with hunting, chilled by being plunged in ice cold wa- 

 ter, stood in a current of cold air, or which had to sleep on a cold 

 stone or metal plate, but the first case is likely to be followed 

 by another and another until the whole kennel suffers. The 

 malady becomes for the time infectious and is to be distinguished 

 from distemper largely by the constancy with which it at- 

 tacks the throat and bronchia to the exclusion of other parts of 

 the body. All its victims suffer in the same way in the air pas- 

 sages only, while in distemper different patients are liable to 

 have the inflammation concentrated on different organs, one suf- 

 fering especially in the eyes, another in the nose, another in the 

 throat, the lower air passages or lungs, another in the liver, 

 stomach or bowels, another in the nervous system, and another 

 in the skin. Even apart from this in distemper the same dog 

 is liable to develop in succession morbid phenomena referable to 

 these different parts implying the presence of a germ which pre- 

 vades the whole system and may dominate first the weakest and 

 less resistant organ. The infectious bronchitis on the other hand, 

 starting from invasion by saprophytic organisms, usually confines 

 itself to the bronchial mucosa, and shows little tendency to extend 

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