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 mentioned, is rather in the nature of casual testing than thoroughgoing, systematic, and analytic study.

In addition to the above reports, there are a few concerning the behavior of apes which have been especially trained for purposes of exhibition.  Most interesting of these is that of Witmer (1909), who studied in exhibitions and in his own laboratory the behavior of the chimpanzee Peter.  The varied forms of intelligently adaptive behavior exhibited by this ape convinced Witmer of ideational experience and even of an approach to reasoning.  In his brief report he expresses especial interest in the possibility of educating this “genius among apes” to the use of language.

A chimpanzee named Consul was observed several years ago by Hirschlaff (1905), and his tricks were interestingly described from the pedagogical standpoint.

Similar in character is Shepherd’s (1915) brief description of the stage behavior of Peter and Consul, both chimpanzees.  It is impossible to determine from the account whether these animals are the same as were observed by both Witmer and Hirschlaff.  As no reference is made in Shepherd’s paper to other descriptions of the behavior of these animals and as he adds nothing to what had already been presented, the reader obtains no additional light on ideation.

I have mentioned only samples of the articles on trained anthropoids.  All are necessarily descriptions of the behavior of individuals who had been trained not for psychological purposes but for the vaudeville stage, and although such observations unquestionably have certain value for comparative psychology, it is well known that unless an observer knows the history of an act, he is not able to evaluate it in terms of intelligence and is especially prone to overestimate its value as evidence of ideation.

There remain studies of the apes, dealing primarily with behavior and mental characteristics, which are slightly if at all experimental and deserve to be ranked as naturalistic accounts.  Such is, for example, the book of Sokolowski (1908), in which attention is given to the characteristics of young as well as fairly mature specimens of the gorilla, chimpanzee and orang utan.

The various publications of Garner (1892, 1896, 1900) deal especially with the language habits of monkeys and apes, but observations bearing on ideation are reported.

Wallace (1869) describes certain features of the behavior of an infant orang utan whose mother he shot in Borneo.  He also reports observations concerning the behavior of adult orang utans, many specimens of which were shot by him during his travels.