DR. TH. NEUMANN. 205 



disturbed, the sound seems to be about an octave higher, 

 but the same in form. The spider monkeys make a 

 sound somewhat resembling that of the sooty mangaby, 

 but much less distinct. Moreover, there is some un- 

 certainty still about its meaning, as, although the sound, 

 when uttered to them, attracts their attention, yet further 

 researches indicate that it may also be a term of friendship 

 or endearment, as the spider monkeys occasionally utter 

 it to their images in the mirror. 



One most unmistakable expression in the simian 

 speech is the negative sign of shaking the head from 

 side to side. It has been subjected to many tests which 

 have met with uniform, confirming results. Seeking a 

 source from which this sign may have originated, we 

 conclude that it arises from an effort to turn the head 

 away from something not desired, and that it has 

 gradually crystallized into an instinctive expression of 

 negation or refusal ; while the nod of approval or affirm- 

 ation may have grown out of the instinctive lowering of 

 the head as an act of submission or acquiescence, or from 

 reaching the head forward to receive or procure some- 

 thing desired, or conjointly from these two causes. 

 Anyhow, when a monkey shakes his head in this way 

 and utters a faint sound at the same time, and always 

 does it in the same way and confirms the sign by a posi- 

 tive act of refusal, he means "no." 



One more striking resemblance to human speech is 

 found in the word which is expressed by the formula 

 " egck," used by the capuchin as a warning of the 

 approach of some person or something which he fears or 

 dislikes. As the capuchin uses it, it seems to have a 

 tincture of defiance, something like a "beware," and its 

 equivalent in human speech is very nearly expressed by 

 the sound "ah, ah !" or " ughn, ughn," uttered with a 

 strong staccato effect, as is often used by man in warning 

 or forbidding, and especially in addressing young 



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