592 
REVIEW-GIRARD ON THE TEETH 
distance from the middle ones. These teeth differ much from 
those of the upper jaw ; they are longer, rounder, and almost 
straight. They resemble a true pincer, prolonged in a forward 
direction, and designed to root up or reverse different substances; 
or to attack them in other ways. At the age of two or three 
years they are black, and without polish on their outer surface ; but 
they afterwards become white, and perfectly united to each 
other. Their superior face is not precisely smooth ; it is rather 
irregularly rounded, presenting an anterior border a little more 
distinct than the other, and with a sort of slope. This upper 
face is not surrounded with a ledge or border, as in the ox and 
the dog : it carries, nevertheless, two well-marked longitudinal 
canals. 
The inferior corner teeth are formed like the pincers and 
middle teeth, except that these teeth, smaller and shorter, consti¬ 
tute, as in the upper jaw, a kind of abortion, or supernumerary 
incisors, placed behind the middle teeth and in front of the 
tushes. 
B ,—The tushes are large and long teeth, curved within and 
without; and, in either jaw, and on either side, between the 
corner teeth and the first molars. These four teeth, most useful 
to the animal both for attack and defence, continue to increase 
in size as long as the animal lives, but in different shapes in 
either jaw. The tushes belonging to the upper jaw of a full- 
grown pig, are larger than, but they are not so long as, those of 
the lower jaw. Being drawn from its socket, each of the superior 
tushes looks like a very large tooth, a little pyramidal, the base 
of which is the extremity of the root, and which is curved both 
within and without through its whole extent. The superior 
tush rubs and wears its anterior face against the tush belonging 
to the lower jaw ; but as it grows and lengthens, it turns itself 
outward, raises the lip, and at length pushes beyond it, and 
shews itself on the outside of the mouth. In young animals the 
extremity of this tooth has a black circle, but which afterwards 
disappears, and at different times in different subjects. Its 
internal surface is roughened by several longitudinal channels. 
The tushes of the lower jaw acquire a prodigious length in an 
old animal, particularly in the uncastrated boar. They cross 
the superior tushes as they pass out of the mouth. In propor¬ 
tion as they increase in size they become curved backwards and 
outwards, and at length sometimes assume a spiral form, and 
thus interfere with the motion of the jaws. These occasional 
enlargements are mostly seen in old boars, and it becomes neces¬ 
sary to cut off* these projecting teeth, either with thefile or nippers. 
The temporary tushes are generally very small, compared 
