608 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1914. 
When speech began, as distinct from mere animal stereotyped cries 
and other noises, it is, of course, impossible to say. For the speech of 
certain low savages, consisting of grunts, guttural sounds, and clicks, 
it is fairly obvious that few tongue movements are necessary; but 
wherever languages have become more elaborate—and many of them 
in different parts of the world appear to have had an independent 
origin from more brutelike utterances—we find that the genio- 
glossus muscle comes more and more into play, as is evidenced by its 
tubercles of attachment and by the forward tilt of the chin to give 
elbow room among all the higher races. 
The speech of monkeys is, of course, a myth, and most of our 
anthropoid friends are curiously silent beings. The two exceptions 
appear to be the chimpanzee, which is described by travelers as 
shouting and calling in varied tones in the forest, and certain gibbons, 
which appear to come nearer to us in the variety of articulate utter- 
ances than any other of the Primates. From the series of plaster 
casts shown in the plates, and in many others that are in my possession 
it seems to become evident that, speaking generally, the genial 
tubercles may be taken as some index of social and intellectual 
development. They are not, of course, strictly necessary for speech, 
but it is clear, both from anatomical and general reasons, that they 
greatly facilitate speech. 
It is interesting to watch their development in the normal human 
subject (see figs. 30-32), and I have several casts which illustrate 
this fairly clearly. In all young children they are absent, and up to 
the age of 14 years they make but a small show; in fact, the jaw of a 
child of 14 years almost exactly resembles in this respect that of a 
Bushman or Pygmy; between 14 and 17, however, they appear to 
obtain their full development. How far that development is depend- 
ent upon the use of the muscle it is difficult to say; my own belief is 
that, like many of the roughnesses and ridges upon our bones, they 
are very largely the product of vigorous muscular action, 1. e., nature 
has met the obvious need of the muscle by altering the bone in a 
certain specific direction. | 
For many years I have been endeavoring to get evidence as to the 
presence or absence of the tubercles in deaf mutes. Such as I have, 
so far as it goes, seems to show that in adults who have never acquired 
articulate speech they are quite absent. (See fig. 17.) In the one 
specimen I have from a deaf mute, the bone almost exactly resembles 
that of a Bushman, or a child of 14. 
A glance over the peculiarities of the tubercles in the accompanying 
plates shows how extraordinarily variable they are in different indi- 
viduals and in different races (see figs. 34, 35), but before any safe 
generalized conclusions are drawn from these diversities one ought to 
have many thousands before one for comparison. It seems to me 
