FIELD AND STUDY 



rapid strides of evolution in later geologic time. 

 The chances to win become greater and greater. 

 More and more doors are opened, more and more 

 new ventures are made. Where the invertebrate 

 had but few chances of becoming a vertebrate in 

 Silurian time, the variations were so slight and so 

 slow, the reptile had many more chances of becom- 

 ing a mammal in Mesozoic time,, because the prin- 

 ciple of variation was so much more active. 



As an animal's wants increase, the more strained 

 will be its relations with its environment; and, the 

 more it is out of sympathy with its environment, 

 the greater will be the variation. The cows along 

 the St. John's River in Florida spend much of their 

 time knee-deep or deeper in the water, grazing on 

 the grassy bottom. They are out of sympathy with 

 their environment. Should this continue long 

 enough, no doubt these cattle will begin to show 

 some marked variation toward a better understand- 

 ing between themselves and the St. John's River. 



When we reach man, the tendency to variation 

 is more pronounced than in any other animal — 

 mental variation. Had this not been so, man's prog- 

 ress had been much slower. The rank and file of 

 mankind have been led forward by a few minds that 

 varied vastly from the common type. There have 

 been favored races and favored states and favored 

 ages and favored families in this respect — one 

 brother differing from another as day from night, 

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