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MANUAL OF MODERN FARRIERY. 
The portion of the tooth which is buried in the gums 
is called “ the rootthe nippers are placed parallel to the 
axis of the jaw, that is, perpendicular to it; the dividers are 
somewhat oblique, and the corner teeth still more so, with 
their roots turning inwards; the semicircle formed by the 
roots of these teeth is considerably narrower, and occupies 
less space than that of the free portion. 
The length, shape, and proportions of the roots change 
according to the different degrees of age, and present some 
variations, which it is necessary to describe. During the time 
of the protrusion of the tooth, the root is generally round, 
short, and quite hollow ; its internal cavity, the sides of 
which are very thin, is only of temporary duration, and does 
not present, like the external cavity, a sort of funnel, which 
is peculiar to the latter. It buries itself deeply, is prolonged 
externally, surrounds the outer funnel, and contains a pulpy 
substance that appears to be the central germ of vitality 
and nourishment to the tooth. According as the animal 
advances in age, a progressive diminution of this cavity takes 
place, commencing at the bottom, and beginning towards 
the inner edge of the tooth; it is collected from the side 
next the root. The latter lengthens, continues constantly 
to grow, and the fresh portions, instead of being rounded, 
are at first triangular, and then flattened from side to side ; 
and lastly, at a period that varies in some horses according 
to the teeth, the cavity disappears altogether ; the root is 
then pointed at its termination, and entirely ceases to grow 
The entire length of the temporary incisors varies from 
an inch and a quarter to an inch and three quarters ; and 
the permanent incisors from two inches and a half to three 
and a quarter. Their form is not the same throughout. 
Thus, next to the surface of wear, they become flattened 
from front to rear, they narrow towards the edge of the 
