the chin against a knee, or grasp the halter or bridle-rein. Windsuckers need no resting-point; and in examining horses for this defect, veterinarians must be careful not to mistake a habit which has been mentioned by Nicklas, which most practitioners have seen, and which consists in a noise produced in rubbing the lips firmly against each other. Nicklas says this is playing with air, and not swallowing it. I have seen it in cart-horses and other animals that were not crib-biters or wind-suckers, and the noise made in smacking the lips was considerable.

In the act of crib-biting the act of respiration is momentarily suspended, the glottis closed, the head flexed, neck arched, and muscles of the chest and abdomen fixed. At this moment there is a noise produced in the pharynx very similar to that of eructation. The larynx and hyoid bone are depressed and fixed, the pharynx expanded, and the air which passes into this is on the relaxation of the parts partly swallowed and partly returned by the nose. Gerlach says that, according to the dexterity with which the act is effected, is little or much air swallowed, and some horses become rapidly tympanitic.

When horses first begin to crib-bite, and sometimes inveterate crib-biters, they only indulge in the practice at intervals; some whilst eating, others after feeding, and others when standing in the stable without food before them. During attacks of acute disease the animals do not attempt the act.

Crib-biters are very liable to attacks of colic. When the oesophagus has undergone changes there is a tendency to choking, and in some instances the animals become subject to vomiting. Cribbiters are unfit for hard work, and from the weakened condition of their system are liable to other diseases.

Crib-biting has been looked upon both as a vice and as an unsoundness.

Mr Oliphant remarks:-" Crib-biting, being an unnatural sucking in of the air, must be to a certain degree injurious to digestion, must dispose to colic, and so interfere with the strength and usefulness and health of the horse. Some crib-biters are good goers, but they probably would have possessed more endurance had they not acquired this habit; and it is a fact well established, that as soon as a horse begins to become a crib-biter, he, in more than nine cases out of ten, begins to lose condition. He is not to the experienced eye the horse he was before. The wear of the front teeth, and even the frequent breaking of them, makes a horse old before his time, and sometimes renders it difficult or almost impossible for him to graze.

"Crib-biting, which has not yet produced disease or alteration of structure, is not an unsoundness, but is a vice under a warranty that a horse is sound and free from vice.' Thus, where an action was brought on the warranty of a horse which had been sold for ninety guineas, the question was, whether crib-biting, which was the vice in question, was such a species of unsoundness as to sustain the

action. The horse had been warranted sound generally. Some eminent veterinary surgeons were called as witnesses, who stated that the habit of crib-biting originated in indigestion; that a horse by this habit wasted the saliva which was necessary to digest his food, and that the consequence was a gradual emaciation. They said that they did not consider crib-biting to be an unsoundness, but that it might lead to unsoundness; that it was sometimes an indication of incipient disease, and sometimes produced unsoundness where it existed in any great degree. Upon this Mr Justice Burrough said: 'This horse was only proved to be an incipient crib-biter. I am quite clear that it is not included in a general warranty,' and the plaintiff was accordingly non-suited.

"In a later case, a horse was bought warranted 'sound and free from vice,' and an action was brought against the vendor on the ground of its being a crib-biter and wind-sucker. Veterinary surgeons were examined, who said that the habit of crib-biting was injurious to horses; that the air sucked into the stomach of the animal distended it, and impaired its powers of digestion, occasionally to such an extent as greatly to diminish the value of the horse, and render it incapable of work. Some of the witnesses gave it as their opinion that crib-biting was an unsoundness; it was not, however, shown, that in the present instance the habit of crib-biting had brought on any disease, or had, as yet, interfered with the power or usefulness of the horse.

"Mr Baron Parke told the jury, that to constitute unsoundness there must either be some alteration in the structure of the animal, whereby it is rendered less able to perform its work, or else there must be some disease. Here neither of those facts had been shown. If, however, the jury thought at the time of the warranty the horse had contracted the habit of crib-biting, he thought that was a vice, and that the plaintiff would be entitled to a verdict on that head. The habit complained of might not indeed, like some others (for instance, that of kicking), show vice in the temper of the animal, but it was proved to be a habit decidedly injurious to its health, and tending to impair its usefulness, and came, therefore, in his lordship's opinion, within the meaning of the term vice, as used on such occasions as the present."

The vice of crib-biting is one of those defects which indicate the propriety of limiting the period during which an animal may be returned. Some cases are apparent, as already said, from the condition of the teeth, but others require close observation, and can only be detected by watching animals when they are not suspecting that any one is near them. The habit is, however, contracted so rapidly, that it is not fair to the seller to permit a question to arise as to the existence of such a defect a month or two after purchase.

There are not many diseases of the digestive organs which give rise to disputes; it is only those affections that are apt to give rise to symptoms of disturbance at intervals, and which may endanger life.

VOMITING.-Vomiting in the horse may be a symptom of overdistension of the stomach, but in all the cases in which it has recurred in the horse, disease has been found at the cardiac end of the œsophagus. The act of vomiting is eminently an unnatural one in the horse.

But before entering on the question why the horse rarely vomits, I may describe this act in animals in which it occurs freely. The first symptom is the expansion of the chest-drawing air into the lungs so as to fix the ribs and enable the diaphragm to act from them. Then the muscles of the belly act, and at the same time the neck is shortened, its muscles grow rigid, there is a regurgitation in the gullet and ejection through the open mouth. It is found that the fluids usually secreted in moderate quantity in the throat, increase in quantity under the influence of the emetic, and it is probable that this is destined to favour the ejection of materials thrown up from the stomach. When the normal contents of the stomach have been dislodged, and vomiting continues, bile and even stercoral matters are thrown up, proving that the antiperistaltic movement extends even beyond the pylorus along the intestinal tube. The action of the stomach, though not essential to the act of vomiting, tends to close the pylorus, and this favours the pressure of the contents against the open gullet. It is very remarkable how slight the contraction of the stomach is in vomiting, and Francis Bayle demonstrated, in 1681, that if a finger is introduced in the stomach of a dog during the act of regurgitation, there is no perceptible effort noticed on the part of the organ; moreover if the muscles of the belly are rendered powerless by a large incision through them, vomiting cannot occur. Chirac, Schwartz, Hunter, and lastly, Majendie, confirmed the views entertained by Bayle. Majendie's experiments consisted firstly in causing the stomach to be exposed through the walls of the abdomen in a dog, when, from the injection of tartar emetic in the veins, no contraction occurred in the organ, and the contents were not expelled. The second experiment consisted in tying a pig's bladder, in the place of the stomach, filled with liquid, which was expelled by the action of the abdominal walls. The latter experiment simply proved that emesis, or the desire to vomit, occurred without the presence of a stomach in the body, and it is not a fact that the organ is incapable of action, or in no way affected by an emetic, because when the intestinal opening or pylorus has been tied, the unaided stomach proves sufficient to accomplish the rejection of its contents.

The action of the oesophagus has to a certain extent been overlooked in the act of vomiting, though Legallois and Beclard observed its active contractions. No one has denied its antiperistaltic movement, but its contractions are seen to be very violent in cases of impaction of some foreign substance close to the stomach. Liquids are then swallowed till the lower end of the oesophagus is distended, and by a forcible contraction of the latter they are soon expelled.

The conditions favourable to vomiting are susceptibility to the

action of emetics or any influence capable of producing nausea, a moderately distended state of the stomach, and favourable form of the œsophagus, especially at its cardiac end. That the distended state of the stomach, independently of any decided sickness, is sufficient to produce regurgitation, is proved by the remarkable cases of so-called rumination in the human subject. Several instances are recorded in which, either under the control of the will or involuntarily, food is returned to the mouth after a meal.

All the persons who have referred to the subject of the difficulty of vomiting in the horse, have overlooked, to a great extent, the point which my brother has justly insisted on, that the emesis, or the tendency to vomiting, is not readily excited in this animal. Nevertheless there are cases in which it is observed, and vomiting is possible. These are, 1st, Cases of inordinate distension of the stomach; 2ndly, Cases of dilatation of the lower end of the esophagus; 3rdly, Cases of obstruction to the pylorus; 4thly, Ruptures of the stomach; 5thly, Hering refers to cases of vomiting due to ulceration of the mucous membrane of the stomach.

The mechanical impediments to vomiting, insisted on by many physiologists, with the exception of two, and which are the disadvantageous direction of the oesophagus into the stomach, and the tendency of the mucous membrane to fold on itself and plug the cardiac orifice, are all false.

Many have described a spiral valve at the cardiac opening of the stomach, and I here reproduce a drawing of it from Leyh's Anatomy, but no such valve exists. It is simply a false appearance in a dried stomach, from the folds of the mucous membrane curling spirally when pressed upon by the distending air.

The sphincter which Bertin, Lafosse, Fluorens, and many others have taken for granted as existing at the lower end of the esophagus of the horse, certainly does not exist.

The pathological facts, which I have carefully collected and examined, prove to me, firstly, that horses are liable to vomiting, and may manifest the disposition at intervals, or any time when the stomach becomes distended, if the mucous membrane has space enough not to be thrown into folds at the cardiac orifice. The subjoined cut indicates a dilatation of the lower end of the oesophagus, which is indicated during life by the troublesome and frequent rejec

tion of the contents of the stomach. There is no doubt, however, that in cases of inordinate distension of the gastric cavity, especially coupled with spasm of the duodenum, regurgitation occurs. We had a case lately in the practice of the New Veterinary College, in a horse which vomited during the paroxysms of a violent attack of colic. This horse recovered. The late Mr John Field relates a very interesting case of vomiting from distension of the stomach and spasm of the duodenum.

But veterinary surgeons are well aware that in acute vomiting in cases of stomach staggers, the stomach has already given way, and by this the mucous membrane forming hernia, through the laceration, any obstruction at the cardiac orifice is overcome. The close manner in which the organs are applied to each other in the abdomen explains how, with an inert and indeed, torn stomach, by the action of the abdominal walls, ejection readily occurs. Those who may be incredulous that, after the walls of the stomach having given way, there could be any vomiting, may be reminded of a case referred to by Longet, in which a woman, having swallowed sulphuric acid, suffered from violent vomiting up to the time of her death, after which it was found that the walls of the cavity had been completely destroyed.

The frequent ruptures of the stomach have been ascribed to active muscular effort of the organ, but I regard them as due to the pressure of the impacted mass on the paralysed coats. I say paralysed coats, because all hollow organs, unduly distended, suffer a kind of paralysis, or are stretched beyond the limit within which they can act. Doubtless when the muscular coat has partially given way, the pressure during the efforts to vomit would increase the hernia of the mucous lining, and favour the regurgitation.

VOL. V.-No. XXXIV. FEBRUARY, 1863,

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