BROKEN WIND, 115 



creases it in breadth. In expiration, the lungs 

 collapse, the midriff is slackened and advances for- 

 wards, the muscles, between the ribs are also 

 slackened, and allow the ribs to return back, 

 partly by their own elasticity, and likewise by the 

 muscles of the abdomen contracting ; thus, the 

 chest is diminished in capacity, as the lungs col- 

 lapse and lessen in size. The lungs, if healthful, 

 and supported in their proper situation, would, 

 independent of the ribs and abdominal muscles, 

 collapse in expiration, as well as dilate in inspira- 

 tion. The lungs have been supposed to be passive 

 organs in respiration ; but they are so far passive, 

 that they will act independent, as I have said be- 

 fore, of the ribs and abdominal muscles ; and it 

 is the lungs losing this function of collapsing, 

 except by the powerful and increased agency of 

 the expiratory muscles, that constitutes, as I sup- 

 pose, broken wind. Air is admitted into the lungs 

 of a broken-winded horse without any impediment, 

 and the capacity for air appears not at all dimi- 

 nished ; but there is a difficulty in expiration 

 arising from the lungs having lost considerably 

 their power of collasping, and on this account re- 

 quiring a greater and longer effort of the abdomi- 

 nal and other muscles to expel the contained air 

 from them; and instead of being expelled gra- 

 dually and almost imperceptibly, it comes now in 



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