or his companion seems
to have kept up this futile attempt, fumbling and dropping the nut
every few minutes. It never occurred to the mouse to gnaw the hole
larger, as it would instantly have done had the hole been too small to
admit its own body. It could not project its mind thus far; it could
not get out of itself sufficiently to regard the nut in its relation
to the hole, and it is doubtful if any four-footed animal is capable
of that degree of reflection and comparison. Nothing in its own life
or in the life of its ancestors had prepared it to meet that kind of a
difficulty with nuts. And yet the writer who made the above
observation says that when confined in a box, the sides of which are
of unequal thickness, the deer mouse, on attempting to gnaw out,
almost invariably attacks the thinnest side. How does he know which is
the thinnest side? Probably by a delicate and trained sense of feeling
or hearing. In gnawing through obstructions from within, or from
without, he and his kind have had ample experience.

Now when we come to insects, we find that the above inferences do not
hold. It has been observed that when a solitary wasp finds its hole in
the ground too small to admit the spider or other insect which it has
brought, it falls to and enlarges it. In this and in other respects
certain insects seem to take the step of reason that quadrupeds are
incapable of.

Lloyd Morgan relates at some length the experiments he tried with his
fox terrier, Tony, seeking to teach him how to bring a stick through a
fence with vertical palings. The spaces would allow the dog to pass
through, but the palings caught the ends of the stick which the dog
carried in his mouth. When his master encouraged him, he pushed and
struggled vigorously. Not succeeding, he went back, lay down, and
began gnawing the stick. Then he tried again, and stuck as before, but
by a chance movement of his head to one side finally got the stick
through. His master patted him approvingly and sent him for the stick
again. Again he seized it by the middle, and of course brought up
against the palings. After some struggles he dropped it and came
through without it. Then, encouraged by his master, he put his head
through, seized the stick, and tried to pull it through, dancing up
and down in his endeavors. Time after time and day after day the
experiment was repeated with practically the same results. The dog
never mastered the problem. He could not see the rel