UNFOLDING OF MAN’S INTELLIGENCE 
tion, ninety-five per cent of his culture history thus far 
had been completed. When Cro-Magnon man appeared 
in Europe, ninety-seven and one-half per cent or more of it 
had elapsed. By the time the Ice Age had at last come to 
an end in Europe, ninety-nine per cent was already a 
thing of the past. The beginning of the Age of Metals and 
of the knowledge of writing in the most advanced por- 
tions of the globe occurred only something like 5,000 or 
6, 000 years ago. Hence the entire historical portion of 
man’s existence, the only part which we know through 
written records, amounts to but one-half of one per cent 
of his whole career up till now. It is this fraction of one 
per cent that has witnessed the blossoming of civilization 
in Babylonia, in Egypt, in India, in China, and elsewhere. 
It represents the time between the building of the Pyra- 
mids and the invention of the aeroplane and the radio. 
Of course, the precise figure of 1,000,000 years for the total 
length of man’s existence as a tool user is an arbitrary one. 
It may have to be cut in two on the one hand or doubled 
on the other, in the light of future discoveries. But for 
the time being it will serve its purpose of helping us to 
realize what a very brief space of time is allotted to the 
historical epoch by contrast with the long prehistoric 
period that went before. 
Recent discoveries have shown that during the earlier 
and by far the greater part of the life history of our race, 
more than one kind of man existed. The human species of 
today, in all its various races and subraces, represented at 
first but one among several different forms of which re- 
mains are already known. Moreover, there were almost 
certainly others not yet discovered, or which died out 
without leaving any traces of themselves in the form of 
fossils. How long any of these now extinct forms sur- 
vived we do not yet know. Some may have lingered on in 
out-of-the-way regions until comparatively recent times, 
as that strange monster, Rhodesian man, may possibly 
have done in South Africa. The existing type has achieved 
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