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50 The Management and Diseases of the Dog. 
The full-grown dog has usually twenty teeth in the upper 
and twenty-two in the lower jaw, with two small supernu- 
merary molars. All of them, with the exception of the 
tushes, are provided with a long neck covered by the gums, 
and separating the body of the tooth from the root. The 
projecting portion of the teeth is more or less pointed, and 
disposed so as to tear and crush the food on which the dog 
lives. They are of moderate size when compared with 
those of other animals, and are subject to little loss of sub- 
stance compared with the teeth of the horse. In most of 
them, however, there is some alteration of form and sub- 
stance, both in the incisors and the tushes; but this de- 
pends so much on the kind of food on which the animal 
lives, and the consequent use of the teeth, that the indica- 
tion of the age by the altered appearance of the mouth is 
not to be depended upon &fter the animal is four or five 
years old. The incisor teeth are six in number in each 
jaw, and are placed opposite to each other. In the lower 
jaw, the pincers, or central teeth, are the largest and the 
strongest ; the middle teeth are somewhat less, and the 
corner teeth the smallest and the weakest. In the upper 
jaw, however, the corner teeth are much larger than the 
middle ones ; they are farther apart from their neighbours, 
and they terminate in a conical point, curved somewhat 
inwards and backwards, 
As long as the teeth of the full-grown dog are whdle, 
and not injured by use, they have a healthy appearance, 
and their colour is beautifully white. The surface of the 
incisors presents, as in the ruminants, an interior and 
cutting edge, and a hollow or depression within. This 
edge or border is divided into three lobes, the largest and» 
most projecting forming the summit or point of the tooth. 
The two lateral lobes have the appearance of notches cut 
on either side of the principal lobe, and the union of the 
three resembles the jewr de lis, which, however, is in the 
process of time effaced by the wearing out of the teeth 
(Figs. 6 and 7.) 
