t difficult at first to regard such relics as indications of the
mental stature of the people who made and possessed them; but a little
thought will show that a man who used a rough stone ax in the time of the
ancient Celts could not possibly have had a mind which included the
conception of a finished iron tool or modern mechanism. So in all
departments of human culture, the evolution of material objects may be
justly employed in interpreting and estimating the mental abilities of
ancient peoples.

Language is undoubtedly the most important single intellectual possession
of mankind, for it constitutes, as it were, the very framework of social
organization. Without a ready means of communication the myriad human
units who perform the varied tasks necessary for the economic well-being
of a body-politic would be unable to coordinate their manifold activities
with success, and the structure of civilized societies at least would
collapse. It needs no legend of a Tower of Babel to make this plain. So
fundamental is this truth that although we may not have recognized it
explicitly, we unconsciously form the belief that speech and language are
exclusive properties of the human species, and even more characteristic of
man alone than the power of reason itself. While organized language is
clearly something that as such we do not share with the lower animals,
nevertheless we cannot regard the communication of ideas or states of
feeling by sound as an exclusive property of mankind. All are familiar
with the difference between the whine and the bark of a dog and with the
widely different feelings that are expressed by these contrasted sounds.
And we know too that dogs can understand what many of their master's words
signify, as when a shepherd gives directions to his collie. We could even
go further down in the scale and find in the shrill chirping of the
katydid at the mating season a still more elementary combination of
significant instinctive sound elements. To the comparative student the
speech of man differs from these lower modes of communication only in its
greater complexity, and in its employment of more numerous and varied
sounds,--in a word, only in the higher degree of its evolution. And it is
even more evident that the diverse forms of speech employed by various
races have gradually grown to be what they now are.

At the outset it is well to distinguish between writing, as the
conventional mode of symbolizing words, and