=Caries= at first pains, but at last destroys all feeling or life in the tooth; the dead organ ceases to possess any vital quality; it loses all power of self-preservation, and is a mere piece of dead matter opposed to a living agent. In consequence, it breaks away, while the opposing molar projects more forward from the absence of attrition. The healthy tooth at last bears against the unprotected gum, upon which it presses severely, and provokes the greatest agony. The animal endeavors to prevent the prominent tooth from paining the jaw by masticating entirely upon the sound side. Hunger is slowly, and perhaps never, satisfied by such imperfect comminution; the outside of the upper molars and the inside of the lower molars become slanting; the first being almost as sharp as razors, wound the membrane of the mouth and lay open the hand which is thrust into the cavity. [Illustration: THE MOLAR TEETH HAVE BEEN GROUND SLANTING, AND HAVE SHARP EDGES, FROM THE HORSE MASTICATING ONLY UPON ONE SIDE. ] If the disease be still neglected and permitted to increase, the stench grows more formidable; nasal gleet appears; the discharge is copious, accompanied by a putrid odor; osseous tumors commence; the bones of the face are distorted; the eye is imprisoned, and ultimately obliterated within the socket by actual pressure; eating becomes more and more painful, until starvation wastes the body and reduces the horse to a hide-bound skeleton. If such a case be taken early, its cure is easy and certain; the dead tooth must be extracted, and the prominent molar shortened by means of the adjusting forceps and the guarded chisel, invented by Mr. T. W. Gowing, veterinary surgeon, of Camden Town. Then the sharp edges must be lowered by the tooth-file, and if these things appear to occupy time, it is better done at two or even three operations, than unduly prolong the agony of a sick animal. This being accomplished, all is not ended; the horse's mouth must, from time to time, be again and again operated upon; nor will the creature offer much opposition to the proceeding, if only proper gentleness be observed. Aged horses, from the contraction of the lower jaw, (which change is natural to increase of years in the equine race,) frequently have their upper molars ground to a knife-like sharpness. They wound the inside of the cheeks, cause a disinclination to eat, and provoke a dribbling of saliva. The cure is the tooth-file, which should be applied until the natural level is attained. This should be followed by the frequent use of the wash recommended for _aphtha_, or by the chloride of zinc lotion.