TIME AND CHANGE 
Carboniferous times; when the first pair of lungs 
grew out of a fish’s air-bladder, probably in Triassic 
times; when the first four-chambered heart was 
developed and double circulation established, prob- 
ably with the first warm-blooded animal in Meso- 
zoic times. 
These humble forms started the brain, the nerv- 
ous system, the circulation, sight, hearing, smell; 
they invented the liver, the kidneys, the lungs, the 
heart, the stomach, and led the way to every organ 
and power my body and mind have to-day. They 
were the pioneers, they were the dim remote fore- 
bears, they conserved and augmented the fund of 
life and passed it along. 
All their struggles, their discipline, their battles, 
their failures, their successes, were for you and me. 
Man has had the experience of all the animals be- 
low him. He has suffered and struggled as a fish, 
he has groveled and devoured as a reptile, he has 
fought and triumphed as a quadruped, he has lived 
in trees as a monkey, he has inhabited caves with the 
wolf and the bear, he has roamed the forests and 
plains as a savage, he has survived without fire or 
clothes or weapons or tools, he has lived with the 
mastodon and all the saurian monsters, he has held 
his own against great odds, he has survived the long 
battles of the land and the sea, he weathered the 
ice-sheet that overrode both hemispheres, he has 
seen many forms become extinct. In the historic 
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