WAYS OF NATURE 
would go through and then try to pull them after 
him. All night he 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 
hfe 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 attempt- 
ing to gnaw out, almost invariably attacks the thin- 
nest side. How does he know which is the thinnest 
side? Probably by a delicate and trained sense of 
feeling or hearing. In gnawing through obstruc- 
tions 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. 
164 
