ing detailed
descriptions, I need only repeat my conclusion, from the summation of
evidence, that this young orang utan exhibited numerous free ideas and
simple thought processes in connection with the multiple-choice
experiment. His ultimate failure to solve the second problem is
peculiarly interesting, although in the light of other features of his
behavior by no means indicative of inferior intelligence.

The various supplementary experimental tests which I employed are in no
wise importantly distinguished from those used by other observers. The
box stacking experiment has, according to my private information, been
used by Koehler. It is obviously important that such tests be applied in
the same manner to individuals not only of the different genera of
anthropoid apes, but of different ages, sex, and condition of training.

The box stacking experiment, although it yielded complete success only
as a result of suggestion on my part, proved far more interesting during
its progress than any other portion of my work. In connection with it,
the orang utan exhibited surprisingly diverse and numerous efforts to
meet the demands of the situation. It is fair to characterize him as
inventive, for of the several possible ways of obtaining the banana
which were evident to the experimenter, the ape voluntarily used all but
two or three, and one of these he subsequently used on the basis of
imitation.

Had Julius been physically and mentally mature, my results would
undoubtedly have been much more impressively indicative of ideas, but
even as matters stand, the survey of my experimental records and
supplementary notes force me to conclude that as contrasted with the
monkeys and other mammals, the orang utan is capable of expressing free
ideas in considerable number and of using them in ways highly indicative
of thought processes, possibly even of the rational order. But
contrasted with that of man the ideational life of the orang utan seems
poverty stricken. Certainly in this respect Julius was not above the
level of the normal three-year-old child.

In common with other observers, I have had the experience of being
profoundly impressed by the versatility of the ape, and however much I
might desire to disprove the presence of free ideas and simple reasoning
processes in the orang utan, I should feel bound to accept many of the
results of my tests as evidences of such experience.

I have attempted to indicate briefly the histor