. Human and comparative anatomy, physiology, and hygiene . esents the teeth of an insect-eating animal. 38. In animals that live on insects the molar teethare raised into conical points, which lock into depressionsin the teeth of the opposite jaw. (Fig. 10.)2* 18 ANATOMY, THYSIOLOGY, AND HYGIENE. Q. How are the teeth arranged in animals that eat insects ? 39. The movement of the lower jaw varies in differ-ent animals. In flesh-eating animals, as the cat andlion, the movement is hingelike, and the molar teeth arecutting instruments like shears. In the ox and horsethe movement is lateral, and th
. Human and comparative anatomy, physiology, and hygiene . esents the teeth of an insect-eating animal. 38. In animals that live on insects the molar teethare raised into conical points, which lock into depressionsin the teeth of the opposite jaw. (Fig. 10.)2* 18 ANATOMY, THYSIOLOGY, AND HYGIENE. Q. How are the teeth arranged in animals that eat insects ? 39. The movement of the lower jaw varies in differ-ent animals. In flesh-eating animals, as the cat andlion, the movement is hingelike, and the molar teeth arecutting instruments like shears. In the ox and horsethe movement is lateral, and the molar teeth are grind-ing instruments like a millstone. In gnawing animals themovement is backward and forward, with no lateral mo-tion. In man we find a moderate degree of the threemovements — cutting, grinding, and gnawing. Q. What is the movement of the jaws in flesh-eating animals ?In grain eating ? In gnawing ? In man ? Remark. — Observe the movements of the lower jaw in man, the cat, squirrel, and horse, to illustrate this paragraph. Fig. Fig. 11. Lower jaw of a squirrel. 1. The enamel of the gnawingtooth. 2. The ivory. 3. The lateral furrows of the molar teeth. 40. The molar teeth of squirrels, rabbits, and ratshave lateral furrows upon the crown, so that the forwardand backward movement of the jaws grinds the food asperfectly as the lateral motion of the jaws of a horse.(Fig. 11.) Q. How are the molar teeth of squirrels furrowed ? Wha isthe effect of this in grinding food ? TEETH 19 41. To prevent the teeth from decaying, they mustbe kept clean. The teeth and gums should be cleanedby using a soft brush and water after every meal; alsobefore going to bed and after rising in the morning. Q. Why must the teeth be kept clean { How should they becleaned ? How often 1 42. The teeth should not be used to crack nuts, bitethreads, or picked with pins. Ivory or quill tooth-picks should be used. Q. For what purposes should the teeth not be used ? REVIEW. SO, 31, 32, 33,
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