TIME AND CHANGE 
generalized organization has many chances. Man 
is one of the most generalized of animals; no special 
tools, no spécial weapons — his hand many tools and 
weapons in one. Hence he is the most adaptable 
of animals; all climes, all foods, all places are his; he 
is master of the land, of the sea, of the air. 
Animal life is often curiously interdependent. I 
asked our guide in the Adirondacks if there were 
any ravens there. “Not nearly as many as there 
used to be,”’ he said, and his explanation of their 
disappearance seems thoroughly scientific; it was 
that the wolves and the panthers kept them in meat, 
and now that these animals had disappeared, the 
ravens had little to feed upon. If the moose were 
compelled to graze from off the ground, like a sheep 
or a cow, the species would probably soon become 
extinct. Osborn thinks it probable that the huge 
beast called titanothere finally became extinct early 
in Tertiary times owing to the form of its teeth, 
which were of such a type that they could not 
change to meet a change in the flora upon which the 
creature fed. Of course we shall never know what 
narrow escapes our race had from extinction in the 
remote past; some forms have ended in a blind alley, 
like the sea-urchin and the oyster. Arthropoda have 
continued to evolve and have reached their high- 
water mark of intelligence in bees and ants. The 
vertebrates went forward and have culminated in 
man. Bergson thinks that in the vertebrates intel- 
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