Animal Life in Field and Garden

by Jean-Henri Fabre

“They must come out soon to leave room for the new teeth that are to take their place. The others will get loose, too, and the twenty that you have now will be succeeded by twenty others, to which, sooner or later, will be added twelve more which come only once. These last occupy the back part of the jaws, three on each side, top and bottom. Thus the final number will be thirty-two.

“These thirty-two teeth are divided into three classes according to their shape and the work they must do. The same names being repeated top and bottom and right and left, I show you merely the eight teeth of half a jaw. In every tooth there are two parts to be distinguished, the crown and the root. The root is the part that is embedded in the jaw-bone like a nail hammered into wood; the crown is the part that comes into view, and it may be likened to the head of a nail. The root holds the [[15]]tooth in place, fixes it firmly; the crown cuts, tears, and grinds the food.

“In the two front teeth in each half-jaw the crown grows thinner toward the top. The edge is straight and sharp, fitted for cutting food, dividing it into small mouthfuls. Therefore these teeth are called incisors, from the Latin incidere, meaning to cut. Their root is a simple pivot. The next tooth is called canine. Its root is a little longer than those of the preceding teeth, and its crown is slightly pointed. The dog, the cat, the wolf, and carnivorous animals in general have this tooth shaped like a powerful fang, which serves to catch and hold prey, but above all acts as a weapon in attack and defense. It is the canine teeth that you see crossing one another, long and pointed, two on each side, when you raise the upper lip of a cat or a dog. Because of these remarkable fangs of carnivorous animals, especially the dog, which in Latin is canis, the name canine has been given to the teeth that in man are like them, if not in form and use, at least in the position they occupy.

“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 [[16]]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.” [[17]]

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?”