_Toothache._--This is rare in the horse and is mostly witnessed when there is decay of a tooth or inflammation about its root. Toothache is to be discovered in the horse by the pain expressed by him while feeding or drinking cold water. I have seen horses, affected with toothache, that would suddenly stop chewing, throw the head to one side, and slightly open the mouth. They behave as though some sharp body had punctured the mouth. If upon examination, no foreign body is found, we must then carefully examine each tooth. If this can not be done with the hand in the mouth, we can, in most instances, discover the aching tooth by pressing each tooth from without. By tapping the teeth in succession with a hard object, such as a small hammer, the one that is tender may be identified. The horse will flinch when the sore tooth is pressed or tapped upon. In most cases there is nothing to be done but extract the decayed tooth, and this, of course, is to be attempted by the veterinarian only. _Deformity._--There is a deformity, known as parrot-mouth, that interferes with prehension, mastication, and, indirectly, with digestion. The upper incisors project in front of and beyond the lower ones. The teeth of both jaws become unusually long, as they are not worn down by friction. Such horses experience much difficulty in grazing. Little can be done except to examine the teeth occasionally, and if those of the lower jaw become so long that they bruise the "bars" of the upper jaw, they must be shortened by the rasp or saw. Horses with this deformity should never be left entirely at pasture. The method of determining the age of a horse by the teeth is illustrated in Plate IV. DISEASES OF THE MOUTH. LAMPAS. Lampas is the name given to a swelling of the mucous membrane covering the hard palate and projecting in a more or less prominent ridge immediately behind the upper incisors. The hard palate is composed of spongy tissue that fills with blood when the horse is feeding, which causes the ridges to become prominent, and they then help to keep feed from dropping from the mouth. This swelling is entirely natural and occurs in every healthy horse. Where there is some irritation in the mouth, as in stomatitis or during teething, the prominence of the hard palate may persist, owing to the increased blood supply. In such cases the cause of the irritation should be nought for and removed. By way of direct treatment, slight scarification is the most that will be required. Burning the lampas is barbarous and injurious, and it should never be tolerated.