D74 



PRACTICE OF AGRICULTURE. 



Ill; 



body extending in some as the dog, pig, &c. into the pelvis ; but in the horse it is less considerable from 



which he is not subjected to epiplocele as they are. Its uses are unknown. "t^raiue, irom 



6400. The stomach and its digestive functions. The horse has one stomach only, and that a verv small 



one, drawing a very wide line of separation by this means between his family and Uie ruminants. In fact 



b33 



the stomach of the horse may 

 be regarded as intermediate be- 

 tween the triturating muscular 

 one of fowls, and the mem- 

 branous one of the Graminf- 

 vora. It is peculiarly constructed 

 to keep up this intermediate 

 character, being partly mem- 

 branous, partly muscular, and 

 partly cuticular; in which latter 

 formation much of its peculi- 

 arity consists, and which it 

 shares in common with asses, 

 rats, and mice; whose habits 

 of living on grain give them a 

 like claim to this wise provision. 

 In a state of rest, or only mode- 

 rately distended, its direction is 

 across the abdomen, with its two 

 orifices directe<l upwards; but 

 the cardiac or recipient orifice, 

 to which the oes6phagus is at- 

 tached, the most so ; while the 

 pyloric or expellent orifice is 

 rather lower, and more inclined 

 backward. The situation of 

 the stomach is immediately 

 contiguous to the diaphragm 

 or great breathing muscle 

 {Jig. 833. k k), from which we 

 are at no loss to understand 

 why a very full meal obstructs 

 respiration ; and why it is so 

 imprudent to gallop a horse very 

 hard after drinking or eating 

 fully. Small as the stomach is 

 in a natural state, it is yet ca- 

 pable of great distention, as has 

 been witnessed in stomach stag, 

 gers, when upwards of half a 

 lundred weight of undigested 

 food has been extracted from 

 At. The membranous portion 

 'of the stomach is gained from 

 the peritoneum ; within this is 

 situated its muscular part, prin- 

 cipally composed of longitudinal 

 and transverse layers, by which 

 ;its motions in digestion are re- 

 'gulated. Around the cardiac 

 or recipient orifice, a strong band of circular fibres is very evident, which effectually constringes this part, 

 and prevents regurgitation or vomiting in the horse, except under extraordinary circumstances of mus- 

 cular relaxation and sympathy. It has been already shown that the anterior part of the alimentary 

 canal, as the mouth, throat, and gullet, are lined with cuticle or skin. This cuticle is continued into the 

 stomach, and lines nearly a half of its internal surface, whose office seems to be a more perfect com- 

 minution of the food, which the horse has no opportunity of remasticating like the ox, sheep, &c. The 

 villous or sensible portion of the stomach is thrown into folds, so as greatly to increase its surface : here 

 the comminuted food in its passage becomes saturated with the solvent gastric juice, and is then passed 

 forward into the intestines. 



6401. The derangements of the stomach may be explained from its anatomy. Though small, and its 

 sensible parts still smaller, yet it is subject to more diseases, and to more frequent derangement, than is 

 generally supposed. It has been proved to be muscular, and that its digestive functions are performed 

 by means of its muscularity. It has also been shown that the contractile energy of the muscular fibre, is 

 mainly gained from the oxygen derived from the blood ; whatever tends to interrupt this separation, as 

 an unhealthy state of the lungs, too quick action of them, &c. must derange the action of the stomach 

 also. The perfection of its digestive powers is also derived from its secreting healthy gastric juice, 

 consequently whatever interrupts this process must likewise interfere with stomachic health ; and that 

 such health is more often impaired than is generally supposed, and that many ailments, attributed to 

 other causes, are really dependent on an affection of this organ, experience and observation will fully 

 evince. Out of condition is a most frequent complaint among horsemen ; their horses are out of 

 condition, and unfit for work: the appearances are various, but are all well known; yet it is seldom 

 considered that it is owing, in every seven cases out of ten, to the stomach being morbidly affected. 

 (64-25.) It is evident that too full feeding must derange it, not only by keeping it constantly dis- 

 tended, and thus weakening its capacity; but bv entrenching too much on its secreting office, and 

 requiring an inordinate quantity of gastric fluid to saturate an undue quantity of farinaceous matter. 

 The hots, that are frequently found on its cuticular coat, and are there probably harmless, sometimes 

 displace themselves, and settle on the villous part, where they must occasion uneasiness and probable 

 inflammation. 



6402. The intestines (Jig. 831. k, I) in the horse maybe considered not merely as secerning organs alone, as 

 in man and many animals, but as really digestive organs, and continuations of the stomachic viscera. 

 This is more particularly the case witli the small intestines, and may therefore entitle them to the term 

 of alimentary canal, and the large to that of the excremental; the former measure from twenty-one to 

 twenty-three yards in length, and the latter from seven and a half to eight yards and a half, according to 

 the size of the animal. The duodenum is the first of the small intestines, commencing at the pyloric 

 orifice of the stomach; the jejunum, which is the next and larger portion, and the flium (Jig. 831. e), 

 which is still longer, form the remainder. The alimentary canal in its structure does not differ from the 

 sensible part of the stomach, having like that two plans of muscular fibres, a circular and a longitudinal, 

 by which its peristaltic motions are regulated ; the longitudinal shortening the canal, and the circular 



diminishing its size. The alimentary part of the intestinal canal ends with this small gut, which itselt 



