The dilated œsophagus or sac superior to the stricture.
The Stricture.
The tube of its natural size.
STRICTURE OF THE ŒSOPHAGUS
More often, however, the whip only tears the internal membrane; the obstruction has been dislodged and removed, but a worse evil has been created. The horse for a time refuses food, and the anxious master wonders "what can be the matter!" At last the pain may cease, the appetite return, for nature may strive to repair the damage. The whip usually tears a flap of membrane, which, obedient to the laws of gravity, hangs pendant within the œsophagus. Our common parent, however, does not, after the human pattern, repair the evil which man induces. She has no mortal hand wherewith to restore the rent membrane to its place. The sides of the wound, however, strive to unite, and by the date when this junction is accomplished, the mucous membrane being inelastic, the magnitude of the canal is seriously diminished. Nature seems to feel that the chief strain of deglutition will be upon this lessened spot, which, therefore, she endeavors to support and strengthen. Lymph is deposited about the place, till ultimately a firm and solid stricture is formed.
This, however, though bad enough, is not the worst. Lymph, after a time, has a tendency to contract. With the diminution of the external ring, of course the internal canal decreases; it is strained at every meal; but straining only provokes its contractive power, till at length hardly the best comminuted morsel could pass the opening. Such, however, rarely enters the strictured œsophagus; the difficulty of deglutition renders it impossible for the appetite to be appeased. No sooner is the food placed before the animal than, because of hunger, induced by prolonged starvation, it is bolted, almost unprepared by mastication and insalivation. Nourishment in that state cannot pass the stricture; it lodges above the contraction; still, hunger impels the horse to eat on. It does so till the œsophagus becomes distended. Gullets have been taken from animals, stretched till they are thinner than the paper upon which this book is printed, and so much enlarged as to admit a boy's clenched fist.
After the affection reaches this stage, the swollen œsophagus, when loaded, presses upon the trachea and larynx so severely as materially to impede the breathing, and it is at this period that instinct develops a strange artifice. The horse has no power to vomit; the fibers of the healthy œsophagus impel but in one direction; still, no sooner has the gullet become distended than the impaired breathing creates a desire to remove the obstruction. The chin is lowered; the crest is thus curved to the utmost, when the muscles of the neck are brought into violent action, and the impacted provender is shot back through the mouth and nostrils.
THE HORSE ENDEAVORING TO CAST UP THE
PROVENDER WITH WHICH THE SAC OF A
STRICTURED ŒSOPHAGUS IS LOADED.