grows, it becomes too large for the first set of teeth.

Their fangs are ab

sorbed, and nature eliminates them to make way for the permanent set. B. Anterior maxillary bone. 1-1, Central permanent nippers nearly full grown. 2-2, Milk teeth worn down. 3-3, 3, Corner milk teeth still showing central mark. 4-4, Tushes concealed within the jaw.

At three years and six months the next nipper is shed all around, and replaced by the permanent tooth. The corner nippers are much worn, and the mark in them barely perceptible. At four years the edges of the central nippers become blunted, and the teeth themselves have grown considerably. The next nipper all around has attained nearly its full size, the edges being quite sharp, and the mark deep and well defined.

A.-Anterior maxillary bone. I- I, Central nippers considerably worn down. 2-2, The next pair fully developed, with their edges slightly worn. 3-3, Corner permanent nippers in a state of growth, with the edges of the cavity sharp, and the mark very plain. 4-4, The tushes showing through the gum, but not full grown.

At five years of age the mouth is furnished with its full complement of teeth; at this age the central cavities of the lower teeth, as compared with the upper, are much more worn, the middle having only a small black spot in the midst of a smooth surface; the next is much worn, and though the corner teeth show the mark distinctly, they also indicate considerable wear. The tush is prominent, the sixth molar is full grown, and the third has made way for the permanent tooth. These are the teeth which furnish the best evidence as to age in case of doubt.

1-1, Central nippers with their marks almost entirely worn out. 2-2, Next nippers, showing marks partially worn. 3-3, Corner nippers with the mark plainly seen, but the edges slightly worn.

grooves inside almost obliterated.

4-4, Tushes with the

The mouth of a six-year-old is the last which affords positively solid ground of judgment as to exact age. The nippers of the lower jaw are known to wear out two years sooner than those of the upper jaw, so that up to eight years the horse's age may be determined with tolerable accuracy.

The lower jaw.

FIG. 7.

1-1, The central nippers with the marks worn out. 2-2, The next nippers with the marks disappearing. 3-3, The corner nippers showing the mark plainly enough, but with the edges of the cavity considerably worn. 4-4, The tushes standing up three-quarters of an inch, with their points only slightly blunted.

Up to the age of eight years the nippers of each jaw are nearly vertical to one another; after this age they begin to stand outward from the straight line, and in the very old horse form a sharp angle. At the age of eight, the

FIG. 8.

FIG. 9.

upper nippers present much the same marks that the lower nippers do at six; both tushes are much worn away at the points, the upper ones more than the lower.

A. Anterior maxillary bone.

1-1, Central nippers worn to a plane surface. 2-2, Next pair still showing a slight remnant of the cavity. 3-3, Corner nippers showing the mark plainly enough. than in the lower jaw of the six-year-old mouth. his ninth year his age cannot be told with absolute certainty, although at good judge will not miss it far.

4-4, Tushes more worn After the horse passes

The following are the changes after the animal passes its ninth year: At nine years the middle nippers are rounded on the inner side, the oval of the second pair and corner teeth become broader, the central enamel is nearer to the inner side, and the marks have disappeared from the teeth of the upper jaw.

At ten years the second pair are rounded on the inner side, and the central enamel is very near the inner side.

At eleven years the corner teeth are rounded, and the central enamel becomes very narrow.

At twelve years the nippers are all rounded and the central enamel has entirely disappeared from the lower jaw, but it still may be seen in the upper jaw.

At thirteen years the middle nippers commence to assume a triangular form in the lower jaw, and the central enamel has entirely disappeared from the corner teeth of the upper jaw.

At fourteen years the middle nippers have become triangular, and the second pair are assuming that form; the central enamel has diminished in the middle nippers of the upper jaw.

At fifteen years the second pair have become triangular, the central enamel is still visible in the upper jaw.

At sixteen years all the teeth in the lower jaw have become triangular and the central enamel is entirely removed from the second pair in the upper jaw.

At seventeen years the sides of the middle nippers are all the same length; the central enamel has entirely disappeared from the upper teeth. At eighteen years the sides of the triangle are longer at the sides of the teeth than in front.

At nineteen years the middle nippers become flattened from side to side, and long from front to rear.

At twenty years the second pair assume the same form.

At twenty-one years all the teeth of the lower jaw have become flattened from side to side, their greatest diameter being exactly the reverse of what it was in youth.