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292 AMERICAN FAKMER'S HORSE BOOK. 



spired, as the technical word is — somewhat more quickly and 

 laboriously than in health ; but, when it is forced out in ex- 

 piration, a singular and characteristic phenomenon appears. 

 This is a peculiar and forcible double action, the ordinary 

 expiration being succeeded by another, evidently a labored 

 one. The cause of this is a change in the structure of part 

 of the lungs, in which the w/ills between some of the air- 

 cells are broken down, so that the usual action of the respir- 

 atory muscles is not sufficiently powerful to expel all the air. 

 Such a condition is called emphysema. In the second expira- 

 tion, all the muscles of the chest are called into play. 



Says " Stonehenge : " " The pressure of unchanged air is a 

 constant source of irritation to the lungs, and, although suf- 

 ficient may be expired easily enough to carry on their func- 

 tions while the body is at rest, yet, instinctively, there is a 

 desire to get rid of the surplus, and hence the two acts of 

 respiration. Immediately after this second act the muscles 

 relax, and the flank falls in, and this it is which catches the 

 eye in so remarkable a manner. On examination after death, 

 the lungs are found to remain enlarged, and do not collapse, 

 as in the healthy condition. They are distended with air ; 

 and thft is especially the case when the emphysema is of the 

 kind called interlobular, in which the air has escaped into 

 the cellular membrane. In the most common kind, however, 

 the cells are broken down, several being united together, 

 while the enlargement pressing upon the tube which has 

 opened into them diminishes its capacity and prevents the 

 ready escape of air." 



TREATMENT. 



A cure of broken wind is impossible, since the trouble 

 originates in an organic injury. The ruptured walls of the 

 pulmonary tissue can never be built up again by the skill or 

 medication of man. But the disease may be greatly palliated 

 by proper attention to feeding, and regular and judicious ex- 

 ercise. The horse should not be watered for at least an hour 

 before going to work, nor be put at severe labor while the 



