approach the character of a specific instinct, and balanced by a
corresponding and opposing dread of loneliness. Our ancestors in the
ages during which our present nervous system became fixed, lived,
apparently, in loosely organised family groups, associated for certain
occasional purposes, into larger, but still more loosely organised,
tribal groups. No one slept alone, for the more or less monogamic family
assembled nightly in a cave or 'lean-to' shelter. The hunt for food
which filled the day was carried on, one supposes, neither in complete
solitude nor in constant intercourse. Even if the female were left at
home with the young, the male exchanged some dozen times a day rough
greetings with acquaintances, or joined in a common task. Occasionally,
even before the full development of language, excited palavers attended
by some hundreds would take place, or opposing tribes would gather for a
fight.

It is still extremely difficult for the normal man to endure either much
less or much more than this amount of intercourse with his fellows.
However safe they may know themselves to be, most men find it difficult
to sleep in an empty house, and would be distressed by anything beyond
three days of absolute solitude. Even habit cannot do much in this
respect. A man required to submit to gradually increasing periods of
solitary confinement would probably go mad as soon as he had been kept
for a year without a break. A settler, though he may be the son of a
settler, and may have known no other way of living, can hardly endure
existence unless his daily intercourse with his family is supplemented
by a weekly chat with a neighbour or a stranger; and he will go long and
dangerous journeys in order once a year to enjoy the noise and bustle of
a crowd.

But, on the other hand, the nervous system of most men will not tolerate