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. [Sidenote: STUDIES IN TROPICAL AFRICA] These 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.