“I here show you a picture of the incisors of the lower jaw. What do you see that will help you to estimate the horse’s age?”
“I see in the first place,” answered Jules, “that the teeth are not all of the same age. The two in the middle, the central incisors as you call them, are newer, since the cavities in their crowns are in good condition, with their sharp edges of enamel. The others are older; their crowns are blunted by friction; in fact, they are a good deal worn down.”
“Are all six of the same cutting?” [[359]]
“Evidently not, for if they were, the middle incisors would show the most wear, as they come first; but exactly the opposite is the case. Since they are quite new and those on each side are already worn, they must belong to the second cutting.”
“That is quite right. Now find the animal’s age.”
“Let me think a moment. I have it. When the horse is between two and a half and three years old the shedding of the milk teeth begins. The first to be replaced are the central incisors. The jaw you show me has these teeth of the second set quite new. Consequently the horse is about three years old.”
Teeth of a Four-Year-Old Horse
“The answer leaves nothing to be desired: the horse is in fact three years old. Now, Louis, what have you to say about this jaw that I next show you?”
“Here, too, the teeth are of different sets, since the central incisors and those next to them are less worn than the others. Moreover, the second incisors are newer than the middle ones, as can be seen from their sharper edges. These second incisors are second teeth; so are the central incisors, which are a little worn because they appeared the preceding year. The third incisors, which show the most wear of all, are milk teeth.” [[360]]