ed it round and round until it was screwed up to the end. The
most remarkable thing was, that however often he was disappointed
in the beginning, he never was induced to try turning the handle
the wrong way; he always screwed it from right to left. As soon
as he had accomplished his wish he unscrewed it again, and then
screwed it in again the second time rather more easily than the
first, and so on many times. When he had become by practice
tolerably perfect in screwing and unscrewing, he gave it up and
took to some other amusement. One remarkable thing is that he
should take so much trouble to do that which is no material
benefit to him. The desire to accomplish a chosen task seems a
sufficient inducement to lead him to take any amount of trouble.
This seems a very human feeling, such as is not shown, I believe,
by any other animal. It is not the desire of praise, as he never
notices people looking on; it is simply the desire to achieve an
object for the sake of achieving an object, and he never rests
nor allows his attention to be distracted until it is done....

"As my sister once observed while we were watching him conducting
some of his researches, in oblivion to his food and all his other
surroundings--'When a monkey behaves like this it is no wonder
that man is a scientific animal!'"[A]

[Footnote A: Romanes: Animal Intelligence, pp. 490, 498.]

In the highest mammals we find also different degrees of attention
and concentration of thought and observation. This difference can
easily be noticed in young hunting dogs. A trainer of monkeys said
that he could easily select those which could most easily be taught,
by noticing in the first lesson whether he could easily gain and
hold their attention. This was easy with some, while others were
diverted by every passing fly; and the latter, like heedless
students, made but slow progress.

It is interesting to notice that one of the perceptions which we
class among the highest is apparently developed comparatively early.
I refer to the aesthetic perception of the beautiful. Now, the
perception of beauty is generally considered as not very far below
or removed from the perception of truth and right. But some insects
and birds apparently possess this perception and the corresponding
emotion in no low degree. The colors of flowers seem to exist mainly
for the attraction of insects to insure cross-fertilization