THE HAZARDS OF THE PAST 



the riot and excesses of animal life far beyond any- 

 thing we know of. And our Hne of descent was tak- 

 ing its chances amid it all. The widespread blotting 

 out of life at the end of Palaeozoic time, and again at 

 the end of Mesozoic times, when myriads of forms 

 were cut off, probably from some convulsion of na- 

 ture or some cosmic catastrophe; and again during 

 the ice age, when the camel, the llama, the horse, 

 the tapir, the mastodon, the elephant, the giant 

 sloth, became extinct in North America — how 

 fared it with our ancestor during these terrible ages? 

 There is no sure trace of him till late Tertiary times, 

 and it is probably not more than two hundred thou- 

 sand years ago that he assumed the upright attitude 

 and began to use tools. Probably in Europe fifty 

 thousand years ago he was living in caves, clothed 

 in skins, contending with the cave bear and cave 

 lion, using rude stone implements, and hunting the 

 hairy mastodon, etc. In Asia the probabilities are 

 that he was farther on the road toward the dawn of 

 history. 



We may think of our descent in the historic period 

 under the image of the stream, though of a stream 

 many times delayed and diverted, even many times 

 diminished by wars and plagues and famine, but a 

 stream with some sort of unity and continuity, since 

 man became man. The stream of life is like any 

 other stream in this respect. Divert or use up part 



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