238 PAN 
remarkable degree in which she is able to understand the meaning of 
spoken language—a degree which is fully equal to that presented by 
an infant a few months before emerging from infancy and therefore 
higher than that which is presented by any brute, as far at least as I 
have met with any evidence to show. Nevertheless, the only attempts 
she makes by way of vocal response are three peculiar grunting 
noises—one indicative of assent or affirmation, another, (very closely 
resembling the first) of dissent or negation, and the third (quite differ- 
ent from the other two) of thanks or recognition of favors. In dispo- 
sition she is somewhat capricious, though on the whole good humored, 
fond of her keepers, and apparently never tired of a kind of bantering 
play which off and on they keep up with her continually. By vocalizing 
in a peculiar monotone (imitative of the beginning of her own ‘song’) 
they are usually able to excite her into the performance of a remark- 
able series of actions. First she shoots out her lips in the well known 
tubular forms (depicted in Darwin’s ‘Expression of the Emotions’ 
141), while at the same time she sings a strange howling note, inter- 
rupted at regular intervals; these, however, rapidly become shorter and 
shorter, winding up to a climax of shrieks and yells, sometimes accom- 
panied with a drumming of the hind feet, and a vigorous shaking of 
the network which constitutes her cage. The whole performance ends 
with a few grunts. 
“A year or two ago it occurred to me that I might try some 
psychological experiments on the intelligence of this animal. * * * 
Having enlisted the intelligent co-operation of the keepers, I requested 
them to ask the Ape repeatedly for one straw, two straws, or three 
straws. These she was to pick up and hand out from among the litter 
in her cage. No constant order was to be observed in making these 
requests, but whenever she handed a number not asked for her offer 
was to be refused, while, if she gave the proper number, her offer was 
to be accepted, and she was to receive a piece of fruit as payment. 
In this way the Ape was taught to associate these three numbers with 
their names. Lastly, if two straws or three straws were demanded, 
she was taught to hold one straw or two straws in her mouth until 
she had picked up the remaining straw, and then to hand the two 
straws or three straws together. This prevented any possible error 
arising from her interpretation of vocal tones—an error which might 
well have arisen if each straw had been asked for separately. 
“As soon as the animal understood what was required, and had 
learned to associate these three numbers with their names, she never 
failed to give the number of straws asked for. Her education was 
