THE DISEASES OF CATTLE. 19 



be about the same as that recommended for common catarrh, 

 wit*" the addition of a counter irritant to the sides of the chest, 

 a little mustard and vinegar will answer the purpose. A bron- 

 chial difficulty of a very alarming character, sometimes pre- 

 vails as an epizootic, and this must be treated the same as 

 epizootic catarrh. 



Description of the hronchial tubes. — The bronchial tubes 

 are a continuation of the trachea, it having entered the thorax, 

 becomes forked or bifurcated ; they are constituted of several 

 pieces, making up so many segments of the circle, overlapping 

 each other so as to admit of extension and contraction in the 

 respiratory acts ; these are connected together and invested by 

 an elastic cellular substance, which imparts to them both 

 strength and elasticity. A further subdivision of the bronchial 

 tubes takes place as they penetrate the substance of the lungs, 

 so that they become very numerous ; as they proceed onwards 

 their calibre continually grows less, until they end in the ex- 

 treme ramifications known as air cells. The bronchial tubes 

 are lined by a membrane common to the trachea. 



INFLAMMATION OF THE LUNGS. 



Inflammation of the lungs, known also as pneumonia, is 

 not usually so prevalent among the bovine, as it proves to be 

 in the equine species, excepting, however, milch cows located 

 in unventilated milking establishments. • 



In such locations diseases of the lungs are often fearfully 

 prevalent, raging at times as an enzootic affection, which gen- 

 erally proves fatal when a large number of a;nimals are con- 

 fined in a small space. 



Among horses this disease is often occasioned by laborious 

 work and feats of speed, which produce rapid and sometimes 

 distressing respiration. But among cattle, whose powers of 

 speed and endurance are pot often put to the test, we may rea- 

 sonably infer that the exciting causes vary in their general 

 character, 



The stimulating and n^orbi^ action of an impure almos- 



