The clicks in question are four in number, or, according to Bleek, “at least six.” They are called the dental, palatal, cerebral, and lateral. The lateral click is the same as that which is employed by our own grooms when urging a horse. The dental is also used by European races as a sound expressive of disappointment, unspeakable contempt, &c. In books it is usually written “tut, tut,” which serves to show how hopeless is any attempt at translating a click into any articulate equivalent. The other two clicks are formed by the tongue operating upon the roof of the mouth. Some remote idea of the difficulty of rendering a language of this kind into any alphabetical form, may be gained by trying to pronounce one of the words which are printed in our European treatises upon them. For example, the Hottentot word for “moon” is printed ║ _khãp_, where ║ stands for the lateral click, _kha_ for a guttural consonant, and ˜ for a nasal twang. With reference to this inarticulate kind of sign-making, which thus so largely prevails among the languages of low races in close organic connection with articulate, it seems worth while to record the following observation which was communicated by Professor Haeckel to Dr. Bleek, and published by the latter in his work already quoted:— “The language of apes has not hitherto received from zoologists the attention which it deserves, and there are no accurate descriptions of the sounds uttered by them. They are sometimes called ‘howls,’ sometimes ‘cries,’ ‘clicks,’ ‘roars,’ &c. Now, I have myself frequently heard in zoological gardens, from apes of very different species, remarkable clicking sounds, which are produced with the lips, and also, though not so often, with the tongue; but I have nowhere been able to find any account of them.” Upon the whole, then, it appears to me extremely probable that in these clicks we have survivals, in lowly developed languages, of a formerly inarticulate condition of mankind; or, as Professor Sayce remarks from a philological point of view, “the clicks of the Bushmen still survive to show us how the utterances of speechless man could be made to embody and convey thought.”[322] * * * * * In its main outlines the hypothetical sketch which I have given follows that which Mr. Darwin has drawn in his _Descent of Man_. As we have already seen, however, there is this important difference. Mr. Darwin entertains only the second of the three alternative hypotheses here presented, or the hypothesis which assumes that the rudiments of articulate speech began in the “ape-like,” or “early progenitors” of man. He does not seem to have entertained the idea of _Homo alalus_ as a connecting link between these early progenitors and _Homo sapiens_. I may, therefore, here briefly give my reasons for thinking it probable that this connecting link had an actual existence.