INTELLIGENCE, POWER, 



civilized state has been so recent and so rapid, and man has 

 been so extensively subjected to out-crossbreeding, that 

 many mutations are seen in the size of his energy-controlling 

 organs. We believe that this principle may also be applied 

 to the size of the brain, the thyroid gland, the adrenal 

 glands, the heart and blood volume, the celiac ganglia and 

 plexuses. 



De Vries pointed out that mutations occur more fre- 

 quently in animals that are hybridized than in line-bred 

 animals. In Africa we saw little evidence of mutation 

 among the antelope, since the lion and the wild dog destroy 

 the slow and the incompetent. The leader of the herd is the 

 male that has defeated all rivals. For thousands of years the 

 herd has been under line-breeding, which is itself an evolu- 

 tion to the advantage of the species. In the antelope the 

 senses of smell, of hearing and seeing, the size of the brain, 

 the thyroid gland, the adrenal glands, the heart, the blood 

 volume, the celiac ganglia and plexuses all the units of 

 the mechanism of these beautiful animals are uniform 

 compared with the mutations of the brain, the thyroid 

 gland, the adrenal-sympathetic system, the heart and the 

 blood volume seen in the thoroughbred horse and in civi- 

 lized man. 



The ancestry of civilized man includes the weak as well 

 as the strong, the incompetent as well as the competent, 

 and the unfit as well as the fit. For this reason we should 

 expect to find a higher percentage of mutations in civilized 

 man than in the line-bred wild animals. 



In civilized man there is greater variation in the size of 

 the brain, the thyroid gland, the adrenal glands, the heart 

 and blood volume, the celiac ganglia and plexuses, resulting 

 in great variations in intelligence, power, and personality, 

 and the incidence to certain diseases. 



In our ninth biological principle we have invoked 

 Berthelot's law of nitroexplosives and van't HofFs law 

 expressing the effect of temperature on chemical activity. 



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