rough grinding surface is maintained notwithstanding the work of many
years. A gland at the posterior of the jaw supplies a tooth-forming
matter, and the growth of fresh laminae is continuous throughout life;
the younger laminae form into line, and march forward until incorporated
and solidified in the tooth.

It is impossible to define exactly the limit of old age, as there can be
little doubt that captivity shortens the duration of life to a great
degree. We can only form an opinion from the basis of growth when young.
As an elephant cannot be fully developed in the perfection of ivory
until the age of forty, I should accept that age in a wild animal as the
period of a starting-point in life, and I should imagine that the term
of existence would be about a hundred and fifty years.

The life of an elephant in captivity is exactly opposed to its natural
habits. A wild Indian elephant dreads the sun, and is seldom to be found
exposed in the open after dawn of day. It roams over the country in all
directions during night, and seeks the shelter of a forest about an hour
before the sun rises. It feeds heartily, but wastefully, tearing down
branches, half of which it leaves untouched; it strips the bark off
those trees which it selects as tasteful, but throws wilfully away a
considerable portion. Throughout the entire night the elephant is
feeding, and it is curious to observe how particular this animal is in
the choice of food. Most wild animals possess a certain amount of
botanical knowledge which guides them in their grazing; the only
exception is the camel, who would poison himself through sheer ignorance
and depraved appetite, but the elephant is most careful in its selection
of all that is suitable to its requirements. It is astonishing how few
of the forest trees are attractive to this animal. Some are tempting
from their foliage, others from their bark (vide the powerfully