One of the words of warning or alarm contains a vowel element closely resembling the short sound of “E.” It terminates with the breathing sound of “H.” It is used to announce the approach of anything that the animal is familiar with, and not afraid of. If the warning is intended to apprise you of the approach of an enemy, or something strange, the same vowel element is used, but terminates with the aspirate sound of “H” pronounced with energy and distinctness. The vowel element is the same in both words, but they differ in the time required to utter them, and the final breathing and aspirate effects. There is also a difference in the manner of the speaker in the act of delivering the word. It plainly indicates that he knows the use and value of the sounds. At the approach of danger the latter word is often given almost in a whisper, and at long intervals apart, increasing in loudness as the danger approaches. The other word is usually spoken distinctly, and frequently repeated. It is worthy of note that the natives use a similar word in the same manner and for the same purpose. There are other sounds which are easily identified but difficult to describe, such as that used to signify “cold” or “discomfort”; another for “drink” or “thirst,” another referring to “illness,” and still another which I have reason to believe means “dead” or “death.” There are perhaps a dozen more words that can readily be distinguished, but as yet I have not been able to determine their exact meanings. I have an opinion concerning some of them, but have not yet reached a final conclusion about them. The chimpanzee makes use of a few signs which may be regarded as auxiliary factors of expression. He makes a negative sign by moving the head from side to side in the same manner as man does, but the gesture is not frequent or pronounced. Another negative sign, which is more common, is a wave-like motion of the hand from the body towards the person or thing addressed. This sign is sometimes made with great emphasis. There is no question as to its meaning. The manner of making this sign is not uniform. Sometimes it is done by an urgent motion of the hand. Bringing it from his opposite side, with the back forward, it is thrust towards the person or thing approaching. The interpretation is, that the ape objects to the approach. The same sign is often made as a refusal of anything offered him. Another way of making this sign is with the arm extended forward, the hand hanging down, and the back towards the person approaching or the thing refused. In addition to these negative signs there is one which may be regarded as affirmative. It is made simply by extending one arm towards the person or thing desired. It sometimes serves the purpose of beckoning. In this act there is no motion of the hand. These signs appear to be innate, and are very similar in character to those used by men to signify the same idea.