INTRODUCTION, 
fr®m each other, are, in general, adapted to their 
way of living. In some it is sharp, the better to 
fit the animal for turning up the earth in which 
its food lies. In some it is long, in order to give 
a greater room for the olfactory nerves, as in dogs, 
who are to hunt and find out their prey by the 
scent. In others it is short, and thick, as in the 
lion, to increase the strength of the jaw, and to fit 
it the better for combat. In quadrupeds that feed 
upon grass, they are enabled to hold down their 
heads to the ground, by a strong tendinous liga- 
ment, that runs from the head to the middle of the 
back. This serves to raise the head, although it 
has been held to the ground for several hours, 
without any labour, or any assistance from the mus- 
cles of the neck. 
The teeth of all animals are entirely fitted to the 
nature of their food. Those of such as live upon 
flesh, differ in every respect from such as live upon 
vegetables. In the latter, they seem entirely made 
for gathering and bruising their simple food, being 
edged before, and fitted for cutting ; but broad 
towards to the back of the jaw, and fitted for 
pounding. In the carnivorous kinds, they’ are 
sharp before, and fitted rather for holding than 
dividing. In the one, the teeth serve as grinds 
stones, in the other, as weapons of defence ; in 
both, however, the surface of those teeth which 
serve for grinding are unequal ; the cavities and 
risings fitting those of the opposite, so as to tally 
exactly when the jaws are brought together. 
