Chapter XII — Anatomy and Diseases of the Gullet, Stomach, and Intestines

The œsophagus, or gullet, of the dog, is constructed in nearly the same manner as that of the horse. It consists of a similar muscular tube passing down the neck and through the chest, and terminating in the stomach, in which the process of digestion is commenced. The orifice by which the gullet enters the stomach is termed the cardia, probably on account of its neighbourhood to the heart or its sympathy with it. It is constantly closed, except when the food is passing through it into the stomach.

The stomach has three coats: the outermost, which is the common covering of all the intestines, called the peritoneum; the second or muscular coat, consisting of two layers of fibres, by which a constant motion is communicated to the stomach, mingling the food, and preparing it for digestion; and the mucous or villous, where the work of digestion properly commences, the mouths of numerous little vessels opening upon it, which exude the gastric juice, to mix with the food already softened, and to convert it into a fluid called the chyme. It is a simpler apparatus than in the horse or in cattle. It is occasionally the primary seat of inflammation: and it almost invariably sympathises with the affections of the other intestines.

The successive contractions of each portion of the stomach, expose by turns every portion of the alimentary mass to the influence of the gastric juice, and each is gradually discharged into the alimentary canal.

As the chyme is formed, it passes out of the other orifice of the stomach, and enters the first intestine or duodenum.

It may be naturally supposed that this process will occasionally be interrupted by a variety of circumstances. Inflammation of the stomach of the dog is very difficult to deal with. It is produced by numerous different causes. There is great and long-continued sickness; even the most harmless medicine is not retained on the stomach. The thirst is excessive; there are evident indications of excessive pain, expressed by the countenance and by groans: there is a singular disposition in the animal to hide himself from all observation; an indication that should never be neglected, nor the frequent change from heat to cold, and from cold to heat.

The mode of treatment is simple, although too often inefficient. The lancet must be immediately resorted to, and the bleeding continued until the animal seems about to fall; and to this should quickly succeed repeated injections. Two or three drops of the croton oil should be injected twice or thrice in the day, until the bowels are thoroughly opened. The animal will be considerably better, or the disease cured, in the course of a couple of days.

There is a singular aptitude in the stomach of the dog to eject a portion of its contents; but, almost immediately afterwards, the food, or a portion if not the whole of it, is swallowed again. This is a matter of daily occurrence. There is a coarse rough grass, ihe cynosaurus cristatus, or crested dog's-tail. It is inferior for the purposes of hay, but is admirably suited for permanent pastures. It remains green after most other grasses are burnt by a continuance of dry weather. The dog, if it be in his power, has frequent recourse to it, especially if he lives mostly in a town. The dry and stimulating food, which generally falls to his share, produces an irritation of his stomach, from which lie is glad to free himself; and for this purpose he has recourse to the sharp leaves of the cynosurus. They irritate the lining membrane of the stomach and intestines, and cause a portion of the food to be occasionally evacuated; acting either as an emetic or a purgative, or both. They seem to be designed by nature to be substituted for the calomel and tartar emetic, and other drugs, which are far too often introduced.

An interesting case of the retention of a sharp instrument in the stomach is related by Mr. Kent of Bristol.

On the 23d of February, Mr. Harford, residing in Bristol, when feeding a pointer-dog, happened to let the fork tumble with the flesh, and the dog swallowed them both. On the following morning, Mr. Kent was desired to see the animal; and, although he could feel the projection of the fork outwardly, which convinced him that the dog had in reality swallowed it, yet, as he appeared well, and exhibited no particular symptoms of pain or fever, Mr. Kent gave it as his opinion that there was a possibility that he might survive the danger, and the animal was sent to him, in order to be more immediately under his care. The treatment he adopted was, to feed him on cow's liver, with a view to keep the stomach distended and the bowels open; and he gave him three times a day half a pint of water, with sufficient sulphuric acid to make it rather strongly sour to the human tongue, with the intention of assisting the stomach in dissolving the iron.

On the following Sunday, the skin, at the projecting point, began to exhibit some indication of ulceration; and on Monday a prong of the fork might be touched with the point of the finger, when pressed on the ulcer. Mr. Kent then determined on making an effort to extract the fork on the following morning, which he accordingly did, and with but little difficulty, assisted by a medical friend of the owner. The dog was still fed on cow's liver; his appetite remained good, and with very little medical treatment the external wound healed. The animal improved rapidly in flesh during the whole time. He left the infirmary in perfect health, and remained so, with one inconvenience only, a very bad cough, and his being obliged to lie at length, being unable to coil himself up in his usual way.

The fork was a three-pronged one, six and a half inches long. The handle, which was of ivory, was digested: it was quite gone; and either the gastric fluid or the acid, or both conjointly, had made a very apparent impression on the iron.

Dogs occasionally swallow various strange and unnatural substances. Considerable quantities of hair are sometimes accumulated in the stomach. Half-masticated pieces of straw are ejected. Straw mingled with dung is a too convincing proof of rabies. Dog-grass is found irritating the stomach, or in too great quantities to be ejected, while collections of earth and dung sometimes threaten suffocation. Pieces of money are occasionally found, and lead, and sponge. Various species of polypus irritate the coats of the stomach. Portions of chalk, or stone, or condensed matters, adhere to each other, and masses of strange consistence and form are collected. The size which they assume increases more and more. M. Galy relates an extraordinary account of a dog. It was about three years old when a tumour began to be perceived in the flank. Some sharp-pointed substance was felt; the veterinary surgeon cut down upon it, and a piece of iron, six inches in length, was drawn out.

The following fact was more extraordinary: it is related by M. Noiret. A hound swallowed a bone, which rested in the superior part of the œsophagus, behind the pharynx, and caused the most violent efforts to get rid of it. The only means by which it could be made to descend into the stomach was by pushing it with the handle of a fork, which, escaping from the hand of the operator, followed the bone into the stomach. Two months afterwards, on examining the stomach, the fork was plainly felt lying in a longitudinal direction, parallel with the position of the body; the owner of the dog wishing mechanically to accelerate the expulsion of this body, endeavoured to push it backwards with his hands. When it was drawn as far back as possible, he inserted two fingers into the anus, and succeeded in getting hold of the handle, which he drew out nearly an inch; but, in order to be enabled fully to effect his object, it was necessary to make an incision into the rectum, and free the substance from every obstacle that could retain it. This he did not venture to do, and he was therefore compelled to allow the fork to pass back into its former position.

About three months after the accident, M. Noiret made an incision, three inches from above to below, and the same from the front backwards. He also made an incision through the muscular tissue. Having arrived at the peritoneum, he made another incision, through which he drew from the abdomen a part of the floating portion of the large intestines, and introduced his fingers into the abdominal cavity. He seized the handle of the fork, which was among the viscera, and free about half-way down, and drew it carefully towards the opening made in the flank. The other half of the fork was found to be closely enveloped by the origin of the mesocolon, which was red, hard, and inflamed. The operator freed it by cutting through the tissues which held the fork, and then drew it easily out. The animal was submitted to a proper course of treatment, and in three weeks afterwards was perfectly cured.

The food, having been converted into chyme by the digestive power of the stomach, soon undergoes another and very important change. It, or a portion of it, is converted into chyle. It is mixed with the bile and a secretion from the pancreas in the duodenum. The white thick liquid is separated, and contains the nutritive part of the food, and a yellow pulpy substance is gradually changed into excrement. As these substances pass on, the separation between them becomes more and more complete. The chyle is gradually taken up by the lacteals, and the excrement alone remains.

The next of the small intestines is the jejunum, so called from its being generally empty. It is smaller in bulk than the duodenum, and the chyme passes rapidly through it.

Next in the list is the ileum; but it is difficult to say where the jejunum terminates and the ileum commences, except that the latter is usually one-fifth longer than the former.

At the termination of the ileum the cæcum makes its appearance, with a kind of valvular opening into it, of such a nature that everything that passes along it having reached the blind or closed end, must return in order to escape; or rather the office of the cæcum is to permit certain alimentary matters and all fluids to pass from the ileum, but to oppose their return.

The colon is an intestine of very large size, being one of the most capacious, as well as one of the longest, of the large intestines. It commences at the cæsum caput coli, and soon expands into a cavity of greater dimensions than even that of the stomach itself. Having attained this singular bulk, it begins to contract, and continues to do so during its course round the cæcum, until it has completed its second flexure, where it grows so small as scarcely to exceed in calibre one of the small intestines; and though, from about the middle of this turn, it again swells out by degrees, it never afterwards acquires its former capaciousness; indeed, previously to its junction with the rectum, it once more materially differs in size.

At the upper part of the margin of the pelvis the colon terminates in the rectum, which differs from the cæcum and colon by possessing only a partial peritoneal covering, and being destitute of bands and cells. It enlarges towards its posterior extremity, and is furnished with a circular muscle, the sphincter ani, adapted to preserve the anus closed, and to retain the fæculent matter until so much of it is accumulated in the rectum as to excite a desire to discharge it.

Also read: Dog Health.