ars preceding.

XIII. SPEECH AND FIRE

A hundred thousand years ago, among our ancestors, who then were only
inarticulate mammals, living in trees and caves, one of them by
himself, or a little group of them together, hit upon the use of
articulate vocal signs as a means of conveying to his mates his needs,
his fears, his desires and threats. It was probably by a happy fluke
that he hit upon this use, or by some transcendent flash of insight due
to a spontaneous variation of ability above that of the average ape; or
else some unusual stress of hunger or danger of attack drove even a
mediocre individual to an unwonted exercise of ingenuity. In any case,
by inventing articulate speech, he brought into existence a new species
of mammal--man. I must leave to your imagination the thousand
transforming effects of this new device for communicating perceptions,
feelings, and intentions. The speaking ape stood to his own species,
and through them to other kinds of animals and to the material
universe, in a different relation from that in which the speechless
stood. The power of combined action among the members of any group
became immeasurably greater than it had previously been. A social unity
of will was possible that could never have existed on earth hitherto.
For all we know, thirty thousand years may have passed away before any
other event occurred among human beings comparable in practical
importance to the invention of spoken language. This, however, was all
the time being gradually perfected under the stress of new experiences
in general and of trying predicaments in particular.

Then, in the fulness of time, and once more by a happy fluke, or by a
stroke of spontaneous genius, or under the pressure of some
unprecedented danger, or through the educative influence of some new
order of experience, one of the speaking apes hit upon the use of fire,
and thereby introduced a new era in the advancement of man. Practically
infinite was the increase of man's new mastery over Nature. Into
temperate and even icy regions he could now penetrate and, as it were,
create around him a little temporary zone of tropical warmth. With
speech had come social unity; with fire at man's disposal came mastery
over matter. But the unity thereby suffered a change. With the
invention of means of creating artificial warmth the social homogeneity
of the tribe began to be broken. Whoever controlled fire controlled the
rest of his group, sin