410 MR. youatt’s veterinary lectures. 
imprisoned in the cells, as it were, by a valve. The succeeding 
inspirations introduce a fresh supply of air, and gradually dilate 
the cells to a greater or less extent; and if the obstruction is of 
some continuance the dilated condition of the cells becomes per¬ 
manent.” 
Progress of the Disease.—-Then we can easily imagine that they 
cannot bear any sudden or violent inspiration, or that the conti¬ 
nuance of sudden and violent inspirations, and the forcible pres¬ 
sure of more air, will rupture the cells ; or that a sudden efibrt of 
expiration, as in violent cough, fruitlessly pressing the confined 
air against the almost obstructed passage, may produce the same 
effect. A second cell is now involved, and gradually shares in 
the distention of the first, and becomes ruptured ; and the greater 
part or the whole of the lobule is gradually broken down, and a 
labyrinth of cells is formed, through which the air can no longer 
be pressed by the weak mechanism of usual expiration, and 
scarcely by the aid of the auxiliary muscles of the abdomen caus¬ 
ing the second effort. 
Peculiarity of Feeding. 
Farther Explication of the Disease. —We are now, perhaps, 
enabled to account for several circumstances attending the dis¬ 
ease. The preceding cough, and that of long continuance, is 
the foundation of the disease, or indicates that irritable state of 
the bronchial membrane with which chronic tumefaction is almost 
necessarily associated. Horses that are greedy feeders, that de¬ 
vour large quantities of not highly nutritious food, or that are 
worked with a stomach distended by this food, are very subject 
to broken wind. There is the pressure of the distended sto¬ 
mach on the diaphragm impeding the motion of the lungs, 
increasing the stress upon eveiy part, and lacerating the thinned 
membranes of the distended cells ; for the very distention of the 
cell renders the membrane thin, and more easily lacerable. More 
depends upon the management of the food and exercise than 
some have been aware of. The post-horse, the coach-horse, and 
the racer, are comparatively seldom broken-winded ; they are 
fed, at stated hours, on nutritious food, that lies in little compass ; 
and these hours of feeding and of exertion are so arranged that 
they seldom work on a full stomach. The agricultural horse is 
too often fed on the very refuse of the farm, and his hours of 
feeding, and his hours of work, are frequently irregular ; and the 
carriage-horse, although fed on more nutritious food, is often 
summoned to work, by his capricious master, the moment his 
meal is devoured. 
