“The next five teeth are the most useful of all. They are called molars, from the Latin mola, a millstone, because they play the part of millstones in grinding the food. For this purpose their crowns are blunt and broad and slightly irregular, not flat like the horse’s molars or with sharp cutting edges like the wolf’s, because man’s food is not composed exclusively of either vegetables or flesh, but of both at the same time. For food as varied as man’s there is need of molars fit for all sorts of service: they must grind like those of the herbivorous animals and cut like those of the carnivorous; in short, they must be like those of both. And, indeed, their wide crowns are suited to vegetable food, and their rather sharp irregularities are adapted to animal food. “The first two are called little molars or, in more learned language, bicuspids, because they have each two cusps or points. They are the least strong of the five and have only one root each. The two little molars, the canine tooth, and the two incisors (of each half-jaw) are the only teeth that are renewed. Multiply them by four and you will have the twenty teeth of the first cutting, teeth that begin to fall out toward the age of seven and are gradually replaced by others. That is the state of Emile’s teeth at present, there being but twenty of them. “The other three teeth, in each half-jaw, come only once. They are the large molars, of which the very end one is also called the wisdom tooth. As in the act of mastication the large molars have to bear strong pressure, the root is composed of several pivots or prongs reaching down each into a special cavity or socket. This makes them strong and firm, so that they can stand pressure both downward and sideways. “To sum up, the grown man has thirty-two teeth in all, sixteen to each jaw; namely, four incisors, two canines, and ten molars. These last are divided into four bicuspids or little molars and six large molars; the milk teeth do not include these last six.” Here Jules had a question to ask. “Ivory and enamel,” said he, “those two substances of different degrees of hardness that you told us were arranged in such a wonderful way in horses’ and wolves’ teeth—are they in our teeth, too?” “Yes, they are there. Ivory forms the entire root, which must serve as a firm support, and it also fills the crown, while enamel merely covers the outside as a hard protecting layer.” “I am going to get the cat and look at her teeth,” said Emile. “Has she twenty, like me, or has she thirty-two?” “Neither twenty nor thirty-two, but thirty when full-grown. Dogs and wolves have forty-two; horses and donkeys forty-four. In fact, the number varies with different animals as much as the shape. Perhaps a few words on this subject will not be out of place.