Irregularities of the teeth may be occasioned by the unequal wearing of some of the teeth or by some of the incisors being broken, which may happen when cattle are pastured on sandy or gravelly soil. The molar teeth may also show irregular wear from similar causes, or from a disease or malformation of the jaw. Their edges may become sharp, or it may happen that a molar tooth has been accidentally fractured. It may also occur that a supernumerary tooth has developed in an unusual position, and that it interferes with the natural and regular mastication of the feed. _Treatment._--The mouth may be examined by grasping the animal's tongue with one hand and partially withdrawing it from the mouth, so as to expose the incisor and molar teeth to inspection. When it is desired, however, to examine the molar teeth with the fingers, so as to obtain a better idea of their condition, an instrument like the balling iron which is used for the horse should be introduced into the mouth, so as to separate the jaws and keep them apart while the examination is being made. Any sharp edges of the molars must be removed by the tooth rasp, such as is used for horses. Any supernumerary tooth which interferes with mastication or any tooth which is fractured or loose should be extracted. In performing such operations it is desirable to throw, or cast, the animal, and to have its head held securely, so as to enable the operator to do what is necessary without difficulty. CARIES OR DECAY OF THE TEETH. The presence of caries may be suspected if the mouth exhales a bad odor and if the animal during mastication occasionally stops as if it were in pain. The existence of caries in a molar tooth may be ascertained by examining the mouth in the manner already described. If one of the molars is found to be carious, it should be extracted. When the crown of the tooth has been destroyed and only the stump or root is left, extraction is impracticable. In case the animal has special value the root stumps may be removed by a veterinarian by the operation of trephining; otherwise, it is best to sell the animal to the butcher. ACTINOMYCOSIS OF THE JAWBONES (BIG JAW OR LUMPY JAW). [See Actinomycosis, p. 440.] INFLAMMATION OF MUCOUS MEMBRANE OF MOUTH (STOMATITIS). The membrane of the mouth may become inflamed by eating some irritating substance or plant, or little vesicles may form in the mouths of calves when they are affected with indigestion, constituting what is termed aphtha.