OF DOMESTICATED ANIMALS. 
415 
as it may be called, of the upper jaw. When the mouth is shut, 
the inferior tush passes between the two in the upper jaw ; it lies 
upon them, and rubs against them, and particularly against the 
corner tooth, or incisor tush. This remarkable overlying of the 
teeth well explains the manner in which the dog lacerates his 
prey when he shakes and drags it, after having penetrated it with 
his tushes. It is certain that these are the principal instruments 
of mischief, for deprived of them, the bite of the dog is com¬ 
paratively harmless. Therefore it is that shepherds file down or 
often extract the tushes of their dogs, and, after that, the sheep 
are rarely or never seriously injured. Sometimes, in old dogs, 
the smaller upper tushes are bent backwards, and interfere ma¬ 
terially with the motion of the lower jaw, and it is found to be 
necessary to file down or to pull out the crooked teeth. 
The milk pincers and tushes pierce the gums before or very 
shortly after the birth, and those in the upper jaw a little pre¬ 
cede the lower ones. These temporary teeth are very white, 
small, and pointed : they protrude very rapidly, become in a 
short time true fleurs-de-lis, and then speedily detach them¬ 
selves and are gone. The period of the appearance of the per¬ 
manent teeth differs in different dogs. It is earliest in large 
dogs. The mastiff has his adult teeth complete when he is four 
or five months old—the teething of the spaniel is not always 
over until he is seven or eight. The incisor teeth first shew 
themselves in the form of sharp points, at some distance from 
each other, and they do not assume the form of the fleur-de-lis 
until they have acquired a certain length. The reason of this is 
plain. In herbivorous animals the permanent incisors do not 
appear until the animal has nearly attained his full growth ; but 
the milk teeth of the dog endure only a short time, because in 
a state of nature, and of servitude too, stronger instruments be¬ 
come necessary to him. 
Of the permanent teeth the pincers always appear first, but 
they precede the middle teeth only a few days. The corner teeth 
appear about the fifth month, and the tushes at the same time, 
or a few days before them. All the teeth preserve their fresh¬ 
ness and their whiteness until the animal is twenty months or 
two years old, when the pincers begin to be a little worn and 
to have their colour tarnished. The first marks of change appear 
in the pincers of the lower jaw—next in the middle teeth of the 
same jaw, and then in the pincers of the upper jaw. The tushes 
do not generally begin to be rounded until all the incisors are 
more or less changed. 
The change of the incisor teeth consists in the gradual efface- 
ment of the fleur-de-lis, or, in other words, the wearing down of 
