between shadow and substance, both when these were presented alternately
and when they were presented simultaneously. This is not far from the
dawn of mind.

In the course of a few lessons, both minnows and sticklebacks learned to
associate particular colours with food, and other associations were also
formed. A kind of larva that a minnow could make nothing of after
repeated trials was subsequently ignored. The approach of the
experimenter or anyone else soon began to serve as a food-signal. There
can be no doubt that in the ordinary life of fishes there is a process
of forming useful associations and suppressing useless responses. Given
an inborn repertory of profitable movements that require no training,
given the power of forming associations such as those we have
illustrated, and given a considerable degree of sensory alertness along
certain lines, fishes do not require much more. And in truth they have
not got it. Moving with great freedom in three dimensions in a medium
that supports them and is very uniform and constant, able in most cases
to get plenty of food without fatiguing exertions and to dispense with
it for considerable periods if it is scarce, multiplying usually in
great abundance so that the huge infantile mortality hardly counts,
rarely dying a natural death but usually coming with their strength
unabated to a violent end, fishes hold their own in the struggle for
existence without much in the way of mental endowment. Their brain has
more to do with motion than with mentality, and they have remained at a
low psychical level.

Yet just as we should greatly misjudge our own race if we confined our
attention to everyday routine, so in our total, as distinguished from
our average, estimate of fishes, we must remember the salmon surmounting
the falls, the wary trout eluding the angler's skill, the common
mud-skipper (Periophthalmus) of many tropical shores which climbs on the
rocks and the roots of the mangrove-trees, or actively hunts small
shore-animals. We must remember the adventurous life-history of the eel
and the quaint ways in which some fishes, males especially, look after
their family. The male sea-horse puts the eggs in his breast-pocket; the
male Kurtus carries them on the top of his head; the cock-paidle or
lumpsucker guards them and aerates them in a corner of a shore-pool.

Sec. 3

The Mind of Amphibians

Towards the end of the age of the Old Red Sandstone or Devonian, a great
step