hology of the ape. I have the
satisfaction of being able to present in the present report the first
systematic experimental study of any feature of the behavior of an
anthropoid ape.

Among the most interesting and valuable of the descriptions which may be
classed among accounts of tests of mental ability is Hobhouse's (1915)
study of the chimpanzee. The subject was an untrained animal, so far as
stated, of somewhat unsatisfactory condition because of timidity.
Nevertheless, Hobhouse was able to obtain from him numerous and
interesting responses to novel situations, some of which may be safely
accepted as evidences of ideation of a fairly high order.

Similar in method and result to the work of Hobhouse is that of Haggerty
(unpublished thesis for the Doctorate of Philosophy, deposited in the
Library of Harvard University). Haggerty's tests of the ability of young
orang utans and chimpanzees to solve simple problems and to use tools in
various ways yielded results which contrast most strikingly with those
obtained in his experimental study of the imitative tendency in monkeys.
His observations, had he committed himself to anything approaching
interpretation, doubtless would have led him to conclusions concerning
the ideational life of these animals very similar to those of Hobhouse.

Koehler, working in the Canary Islands, has, according to information
which I have received from him by letter, made certain experiments with
orang utans and chimpanzees similar to those of Hobhouse and Haggerty.
His results I am unable to report as I have scanty information
concerning them. They are, presumably, as yet unpublished.

In his laboratory at Montecito, California, Hamilton has from time to
time kept anthropoid apes, but without special effort to investigate
their ideational behavior. He has most interesting and valuable data
concerning certain habits and instincts, all as yet unpublished.

To a congress of psychologists Pfungst (1912) briefly reported on work
with anthropoid apes in certain of the German zooelogical gardens. His
preliminary paper does not enable one to make definite statements
concerning either his methods or such results as he may have obtained
concerning ideational behavior. So far as I know, he has not as yet
published further concerning his investigation.

Moebius (1867) has described interesting observations concerning the
mental life of the chimpanzee. But this, like all of the work previously
mentio