ineffectively. Animals far lower in intelligence (e.g., the
pig), surpass him in ability to solve these relational problems because
they use the method of elimination by trial consistently and
effectively. Julius, in these experiments, made a poor showing because
his substitute for trial and error is only slightly developed. Would he
have succeeded better with the same problems if mentally mature?

There are many important features of the results which, for lack of
space, have not been indicated or discussed. They can be developed from
later comparative studies of the data, for in the tables appear all of
the essential facts of response apart from those mentioned in the text.

IV

RESULTS OF SUPPLEMENTARY TESTS OF IDEATIONAL BEHAVIOR

1. Julius, _Pongo pygmaeus_

_Box Stacking Experiment_

In addition to the multiple-choice experiments which have been described
in detail in the previous section, it was possible to conduct certain
less systematic tests of ideational behavior in the monkeys and the
orang utan. From the technical standpoint these tests were relatively
unsatisfactory because only inexactly describable. But their results are
in many respects more interesting, if not also more important, in the
light which they throw on ideation than are those previously presented.
First, in order of time, comes a test which may be designated as the box
stacking experiment. The method will now be described in connection with
an account of the behavior of Julius as contrasted with that of a child
of three years and four months of age.

In the large central cage labelled Z, figure 12, which was twenty-four
feet long, ten feet wide, and ten to twelve feet deep, the following
situation was arranged. From the center of the wire covering of the
cage, a banana was suspended on a string so that it was approximately
six feet from the floor, five feet from either side of the cage, and
twelve feet from either end. From all approaches it was far beyond the
reach of Julius, since it was impossible for him to climb along the wire
roof and thus reach the string. Two boxes were placed on the floor of
the cage several feet from the point directly under the banana. The one
of these boxes was heavy and irregular in shape, as is shown in figures
21, 23 and 24 of plate V. Its greatest height was twenty-one inches; its
least height, eighteen inches; its other dimensions, twelve and sixteen
inches respectively. The smaller and lighte