es of things, e.g. boxes similar in size but different in shape, for
if the prize is always put in a box of the same shape they soon learn
(by association) to select the profitable one. They learn to
discriminate cards with short words or with signs printed on them,
coming down when the "Yes" card is shown, remaining on their perch when
the card says "No." Bred to a forest life where alertness is a
life-or-death quality, they are quick to respond to a sudden movement or
to pick out some new feature in their surroundings. And what is true of
vision holds also for hearing.

Power of Manipulation

Another quality which separates monkeys very markedly from ordinary
mammals is their manipulative expertness, the co-ordination of hand
and eye. This great gift follows from the fact that among monkeys the
fore-leg has been emancipated. It has ceased to be indispensable as an
organ of support; it has become a climbing, grasping, lifting, handling
organ. The fore-limb has become a free hand, and everyone who knows
monkeys at all is aware of the zest with which they use their tool. They
enjoy pulling things to pieces--a kind of dissection--or screwing the
handle off a brush and screwing it on again.

[Illustration: _Photo: W. P. Dando_

BABY ORANG

Notice the small ears and the suggestion of good temper. The mother
orang will throw prickly fruits and pieces of branches at those who
intrude on her maternal care.]

[Illustration: _Photo: Gambier Bolton._

ORANG-UTAN

A large and heavy ape, frequenting forests in Sumatra and Borneo, living
mainly in trees, where a temporary nest is made. The expression is
melancholy, the belly very protuberant, the colour yellow-brown, the
movements are cautious and slow.]

[Illustration: 1. CHIMPANZEE

2. BABY ORANG-UTAN

3. ORANG-UTAN

4. BABY CHIMPANZEES

_Photos: James's Press Agency._

In his famous book on _The Expression of the Emotions in Man and
Animals_ (1872) Charles Darwin showed that many forms of facial
expression familiar in man have their counterparts in apes and other
mammals. He also showed how important the movements of expression are as
means of communication between mother and offspring, mate and mate, kith
and kin.

The anthropoid apes show notable differences of temperament as the
photographs show. The chimpanzee is lively, cheerful, and educable. The
orang is also mild of temper, but often and naturally appears melancholy
in captivity. This is not sugges