INTELLIGENCE, POWER 



living protoplasm of the body. This point could be clarified 

 by determining the basal metabolism of the two animals. 



In a porpoise and a tiger shark, two occupants of the 

 Atlantic Ocean having approximately the same weight, we 

 found an example of the influence of the concentration of 

 oxygen on the size of the brain, the heart, the volume of the 

 blood, and the thyroid gland. 



These two animals represent the warm-blooded and the 

 cold-blooded state in the sea. The porpoise, a lung- 

 breathing, warm-blooded animal, although living in the sea 

 in the midst of slower swimming creatures, lives danger- 

 ously. In constant danger of drowning, the porpoise brings 

 its young into the world, suckles them, and protects them 

 in the presence of sharks the pirates of the sea. 



Immediately after the death of the porpoise we made an 

 incision in the smooth skin and inserted a clinical ther- 

 mometer. It registered the normal human temperature of 

 98.6. The layer of pure white blubber varying from % Q 

 inch in places to 2^-2 inches in thickness recalled the thick 

 skin found in the rhinoceros, the hippopotamus, and the 

 elephant. 



In the case of the African animals, the thick skin serves 

 to insulate them against external heat; in the case of the 

 porpoise a warm-blooded animal living in the cold sea 

 the thick skin serves to preserve the internal heat in a 

 medium colder than air. 



Inasmuch as water abstracts heat twenty-seven times 

 faster than air, the warm-blooded mammal that returned 

 to the sea would be equipped with a larger brain, a larger 



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