ON ENVIRONMENT 



bed of that sea before it began its long process of 

 leakage or evaporation. 



In these regions, so far as is known, the North 

 American cactus seems to have originated. 



Back in the ages before the evaporation of the 

 inland sea was complete, the heat and the moisture 

 and the chemical constituents of the sandy soil 

 combined to give many plants an opportunity to 

 thrive. Among these was the cactus, which was 

 an entirely different plant in appearance from 

 the cactus of today, no doubt, with well defined 

 stalks and a multitude of leaves, each as broad as 

 a man's head. 



As the heat, which had lifted away the inland 

 sea, began to parch its bottom, the cactus, with the 

 same tendency that is shown by every other plant 

 and every other living thing, began to adapt itself 

 to the changing conditions. 



It gradually dropped its leaves in order to 

 prevent too rapid transpiration of the precious 

 life-supporting moisture. It sent its roots deeper 

 and deeper into the damp sub-stratum which the 

 sun had not yet reached. It thickened its stalks 

 into broad slabs. It lowered its main source of 

 life and sustenance far beneath the surface of the 

 ground and found it possible, thus, to persist and 

 to prosper. 



Perhaps there were, in the making of the 



[15] 



