in a corner to nurse his jealousy. While I remain outside the cage, he is so devoted to me that he will scarcely leave me to get something to eat; but when I enter the cage, and reach out my hand toward him, he will shake his little head and utter that peculiar clucking sound. Many of these tests I have repeated over and over with the same results, and, noting the conditions at the time, I am thoroughly convinced that the sign and sound mean "no." I have observed that this sign is always made in the same manner; but sometimes it is accompanied by a clucking sound, while at other times it is a soft whimpering sound, almost like a low plaintive whistle. [Sidenote: SIGN USED WITHOUT SOUND] The sign is frequently used without the sound at all, and I must impress it upon my reader that these results do not always present themselves in every experiment, as much depends upon the mood and surroundings of the subject. I have found that one advantage is to have the monkey confined in a very small cage, as otherwise he will turn away and get out of your reach when you press anything upon him that he does not want. I have also found much better results by having the monkey alone, and where he can neither see nor hear other monkeys. Having discovered the sign of negation among the Simians, I began an investigation to ascertain how far it could be found among the races of mankind. I have carried my search far beyond the limits of local inquiry, and up to this time I have found only a few trifling exceptions in the use of this sign among all the races of men, and those few exceptions are found among the Caucasian race, and appear to be confined to Southern Europe. I have heard that among certain island tribes of Polynesia these signs are reversed, but I have been assured by two officers of the English navy and two of the United States navy, who have visited the islands in question, that such is not the case. Among the Indians, Mongolians, and Negroes I have found no noteworthy exceptions. I have inquired among mothers who have raised families to ascertain when they first observed this sign as an expression among their children; and from the consensus of opinion it appears that this is about the first sign used by infants to express negation. [Sidenote: THE POSITIVE SIGN] I have not found the positive sign, or sign of affirmation, by a nod of the head, to be so general, yet it has a wide range within the human family, and appears to be used to some extent among the lower primates.