The Speech of Monkeys

I have made scores of experiments on this subject, and I find this sign a fixed factor of expression. In one case, where I tried to induce a monkey to allow me to take him into my hands from the hand of his master, he would shake his head each time, and make a peculiar sound somewhat like a suppressed cluck. I would try to coax him with nuts, in response to which he would make the same sound and sign each time, and his actions showed beyond all controversy his intention. I had taught a monkey to drink milk from a bottle by sucking it through a rubber nipple, and after he had satisfied his thirst, when I would try to force the bottle to his lips, he would invariably respond by a shake of the head in the manner described, and at the same time utter a clucking sound. I tried many similar experiments with three or four other monkeys, and secured the same result in each case. In another instance, where a monkey was confined in a small cage so that I could easily catch him in order to tame him by handling, when I would put my hand into the cage to catch him, he would shake his head in this manner and accompany the act by a plaintive sound which was so touching, that I could not obtain my own consent to persecute the little prisoner by compelling him to submit to my caresses.