518 BROKEN WIND. 



dition we call ' brokcn-wincl.' It may, and, as stated previously, 

 often does, seem to usher this state into existence ; but once 

 established, the condition of the minute air-tubes would appear 

 to be the directly opposite of a state of spastic contraction. 

 They are paralytically fixed, existing simply as inert conduits 

 which are not capable of acting expulsive ly on their contents 

 themselves, and only discharge this part of their function in 

 as far as they are acted upon by other contractile agents. 



"The phenomenon of the arrest of the expu*atory act, and the 

 second prolonged contraction of the abdominal muscles, one 

 of the diagnostic symptoms of this disease in the horse, is 

 probably better accounted for by regarding it as an extra 

 expulsive effort employed to empty the paralytically fixed 

 bronchi, than as the regularly recurring eftbrt of the animal 

 machine to rid itself of air extravasated or contained in inter- 

 connective cellular tissue or dilated air-cells. 



It is clearly an eftbrt to overcome the existing dyspna?a, and 

 obtain space for fresh atmospheric air ; so that the point to be 

 determined really is. What is the cause of the dyspnoBa ? is it 

 difficulty of expiration from emphysema and distended air- 

 vessels, or from some impairment of the normal contractile 

 power of the pulmonary tissue ? I believe it follows more 

 largely and more regularly from the latter cause. The cough 

 usually present in all cases of the disease is accounted for 

 much in the same way as we explain the spasm of the bronchial 

 muscular tissue, viz., as resulting from reflected nerve-action ; 

 the irritation seemingly proceeding in a great measure from 

 the extra amount of the secretion in the air-passages, and the 

 difficulty to get rid of this. 



In considering the varied phenomena of this disease, and the 

 relations which they bear severally to each other, as well as 

 that which any one bears to the whole, there ought not to be 

 omitted from our reckoning the changes which so often occur in 

 connection with other organs of the thorax, the heart in par- 

 ticular. 



These two views of the nature of broken-Avind which we 

 have now stated, although probably both true, and the latter 

 more inclusive than the former, I am yet far from regarding as 

 the whole or full statement of the truth. It Avould appear, 

 viewing this diseased condition in its assemblage of plic- 



