JAVA MONKEYS
Among the Java monkeys are several varieties which make very good pets. They show a fair degree of intelligence and docility, and are not generally very vicious. I have not succeeded in making any very good records of these monkeys, although I have observed, without the aid of the phonograph, that they have one or two very distinct and well-marked sounds. I have not up to this time attempted to differentiate their sounds, but in a general way have interpreted the meanings of one or two groups of them, especially those of a friendly character. I may with propriety remark here, that in all the different tongues of monkeys there appear to be certain words which are much more significant, of a much better phonetic type, than the others, and occur much more frequently among their sounds. This appears to be true of the speech or sounds of all the lower animals.
MONKEYS RECOGNISE BY SIGHT
In a former chapter I have described the happy little family in Central Park, which consisted of the five little brown cousins, only a few months ago; but death has reduced their number to two. In this connection I shall mention a very important fact concerning the use of the natural senses of these animals. I have several times been assured that monkeys depended more upon their sense of smell than upon that of sight as a means of recognition, and that in this respect they were very much like the canines. I have made frequent tests of the power of their senses, and am prepared to say with certainty that such is not the case. When I visit the Park, I frequently enter at Sixty-fourth Street and Fifth Avenue, at which place there is a flight of stairs leading from the street down to a large plazza in front of the Old Armoury; and something more than a hundred feet from the foot of the stairway, and nearly at right angles to it, is a window opening into the monkey-house by the cage occupied by these particular monkeys. When I descend the stairway and come within view of this window, they frequently see me as I reach the plazza, and the keeper always knows of my approach by the conduct of the monkeys, who recognise me the instant I come in sight at that distance. At other times I have approached the house from another direction, and come within a few feet of their cage, where I have stood for some time, in order to ascertain whether they were aware of my presence; and on a few occasions have slipped into the house with the crowd, and they did not detect my presence except by sight. It is evident, if they depended upon the sense of smell, that they would have discovered my presence when so near them, although they could not see me. But no matter what the condition of the weather, or how many people are present, the instant one of them sees me he spreads the news, and every inmate of the cage rushes to the window and begins to scream at the top of his voice. If their sense of smell was such as to enable them to detect my presence as a dog would, it is reasonable also that the monkey which possessed the most sensitive organs would have been the first to detect it in each case; whereas, sometimes one monkey, and sometimes another, made the discovery. It is my belief, however, that their sense of smell is much more acute than that of man, but far less so than that of most other animals, especially the dog. HEARING VERY DELICATEThe sense of hearing in these animals is very delicate, as may be seen from the account of Nellie discovering my footsteps on the lower stairway, and as I have witnessed in scores of other cases. The same is true also of their sight; their eyes are like a photo-camera, nothing ever escapes them. I think their organs of taste are also quite sensitive, as I have made some tests from time to time, and find them very hard to deceive. The sense of touch, which is rather obtuse in most animals, is much more acute in these. I have frequently interlaced my fingers with those of some person whom they dislike, and extending the hand towards them, they rarely make a mistake by getting hold of the wrong finger, and yet it has frequently occurred that they could not see the hands at all, and had to depend alone upon the sense of touch. In cases where the hands were very nearly the same size they were not able to select the fingers so readily, but where a lady's hand was used, or that of a boy, the selection was made without hesitancy and without error. I have tried this experiment a great many times with a view to ascertaining to some extent the delicacy of their sense of touch. Another fact that I may mention is, that they do not habitually smell articles of food or other things given to them; but they depend chiefly upon their sight for finding and their taste for choosing their food. My opinion is, that the sense of smell does not play an important part in these affairs. I may add, too, that, in the Cebus, his tail is perhaps the most sensitive organ of touch, although it is not used in this capacity to any great extent. He is generally very watchful over this useful member, because it serves him in so many ways, and I think perhaps it is safe to say that the tail is the last part of the monkey that ever becomes tame.
CHAPTER XIII.
The Extent of my Experiments—Apes and Baboons—Miscellaneous Records of Sound—The Vocal Index.
In quest of the great secret of speech, I have pursued my investigations chiefly in the direction of learning one tongue, but incidentally I have made many detours, and I have recorded the sounds of many other forms of the animal kingdom, besides primates. I have examined the phonation of lions, tigers, leopards, cats, dogs, birds of many kinds, and the human voice in speech, music, and laughter. Besides these, I have examined various musical sounds, especially of the pipe and whistle kinds.
More than a year ago I made some splendid records of the sounds of the two chimpanzees in the Cincinnati collection. I have not had the opportunity to study these apes themselves, as I desired to do, since they are kept so closely confined in a glass house, and for ever under the eye of their keeper, which conditions are not favourable to the best results. I am not prepared therefore to give much detail concerning their speech; but from a careful study of one cylinder containing a record of their sounds, I was able to discern as many as seven different phones, all of which come within the scope of the human vocal organs. I learned one of these sounds, and on a subsequent visit to Cincinnati I succeeded in attracting the attention of the female, and eliciting from her a response. She would come to the lattice door of the inner cage by which I was standing, and when I would utter the sound she would press her face against the door of the cage and answer it with a like sound. The male, however, did not appear to notice it with any degree of concern. I have no idea what the sound meant, and my opportunities have not been such that I could translate it with the remotest degree of certainty. STUDIES IN TROPICAL AFRICAThese apes will be one of the chief objects of my studies in tropical Africa, as I believe them to possess a higher type of speech even than the gorilla. In this opinion, which I reached from the study of other sounds and the types of skull to which they belonged, I am not alone: Mr. Paul Du Chaillu, Mr. E. J. Glave, and others who have seen both of these apes in their native habitat, agree with me on this point. I am aware that this view is not in strict accord with that of Professor Huxley, who assigns the gorilla the highest place next to man in the order of Nature, and the chimpanzee next below him. I shall not here attempt to discuss the question with so high an authority, and I must confess that the vocal index is not yet so well defined that it may be relied upon in classifying apes. One aim I have in view is to study the gorilla and chimpanzee side by side in their native wilds, and to record, if possible, the sounds of their voices in a wild state. From the study of the sounds I have made, I feel confident that all the vocal sounds made by these apes may be uttered by the human vocal organs.
Some months ago I made a record of the voice of the great Anubis baboon, in Philadelphia. I did not expect to find in him an elevated type of speech; but my purpose was to compare it with other Simian sounds, to see if I could not establish a series of steps in the quality of vocal sounds which would coincide with certain other characters. I had found by the study of certain cranial forms that certain vocal types conformed to certain skulls, and were as much a conformation thereof as are the cerebral hemispheres. I then believed, and have had no cause since to recede from it, that the vocal powers were correctly measured by the gnathic index; that the mind and voice were commensurate; and that as the cranio-facial angle widens the voice degrades in quality and scope. In man, I find the highest vocal type, and just as we descend in the cranial scale, the vocal type descends into sounds less flexible, less capable, and less musical. These deductions apply only to mammals; among birds, insects, &c., a different order may prevail.