INTELLIGENCE, POWER, 



animals, for the term "domestication" includes breeding 

 as well as care and training. The influence of breeding and 

 domestication varies with the needs and taste and fancy of 

 man. The influence of man on the energy-controlling organs 

 of the Jersey cow, the Holstein cow, the hen, the pig, the 

 horse has caused these animals to reach a point somewhat 

 near the limit of their physical safety. 



The aims of breeding vary according to the desired end. 

 In the case of the thoroughbred horse and the racing grey- 

 hound, high speed for a short distance being the aim, man 

 takes advantage of the mutations and breeds for a large 

 brain, a large heart, and a large adrenal-sympathetic system 

 but not for a large thyroid gland. 



On the other hand, when man breeds for endurance and 

 companionship, as in the case of the Arabian horse, he 

 breeds for a larger thyroid gland and a smaller brain, heart, 

 and adrenal-sympathetic system. 



When man desires a greater number of eggs from a hen, 

 a larger amount of fat from the hog, better steaks and chops 

 from the beef and sheep, a larger fleece of wool, or a greater 

 amount and richness of milk from the cow, he breeds for 

 tranquility rather than temperament. To produce tranquil- 

 ity, he breeds toward a smaller brain and a smaller adrenal- 

 sympathetic system. To produce more eggs, more fat, beef, 

 wool, and milk, he breeds toward a large thyroid gland in 

 order to maintain a high level of protoplasmic activity 

 hence more eggs and more milk. 



Let us take, for an example, the Jersey cow. By selective 

 breeding, the mind of man has so altered the Jersey cow 

 that she now finds herself largely a chemical factory, 

 taking in a great amount of hay and grain but not trans- 

 forming this prodigious amount of fodder into roaming the 

 fields, escaping from a mountain lion or a pack of wolves, or 

 journeying in adventure to other scenes and other pastures; 

 not knowing the thrill of being hungry and thirsty and 

 finding food and drink; not being permitted to be cold and 



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