evidence of the appreciation which they have of sound. The chattering differs, moreover, from the mere monotonous repetition of a sound and if it has any function, it is probably a function which can be fulfilled only by the apprehension of a series of diverse sounds. It is also of interest to note the statement of Professor Haeckel that he has heard from apes of very different species 'remarkable clicking sounds'; and it has been thought that these sounds are still present in the language of Bushmen.
Mr. E. L. Garner made some years ago a study of the 'speech of monkeys,' and he reached the following conclusions:[1] "The sounds which monkeys make are voluntary, deliberate and articulate. They are always addressed to some certain individual with the evident purpose of having them understood. . . . They wait for and expect an answer, and if they do not receive one they frequently repeat the pounds. They usually look at the person addressed and do not utter these sounds when alone or as a mere pastime. . . . They understand the sounds made by monkeys of their own kind. . . . when imitated by a human being, by a whistle, a phonograph, or other mechanical devices. . . . The fundamental sounds appear to be pure vowels, but faint traces of consonants are found in many words." "As a rule each act of a monkey is attended by some sound." In a later work. Mr. Garner, after study of the apes in their native haunts, says that the chimpanzee has a vocabulary of twenty-five to thirty words; he claims that he learned ten of these words so that he could hold communication with the animals using them.[2]
Mr. Romanes'[3] account of the song, if such it may be called, of the chimpanzee 'Sally' may here be quoted: "It is sung without any regard to notation in a series of rapidly succeeding howls and screams—very loud, and accompanied by a drumming of the legs upon the ground." Mr. Garner has observed similar exhibitions given by chimpanzees. He also heard a performance of the kind in the African forest; the natives and others attributed it to the gorilla, but Mr. Garner thinks it not unlikely that it was given by the chimpanzee.
Darwin[4] calls attention to the fact that two species of the gibbon, the Hylobates agilis and the Hylobates leuciscus have musical powers. In regard to the song of the former he quotes Mr. Waterhouse, who says: "It appeared to me that in ascending and descending the scale, the intervals were always exactly half tones; and I am sure that the highest note was the exact octave to the lowest. The quality of the notes is very musical."
