THE ORGANIC TENDENCY 185 



individual with respect to environmental condi- 

 tions. If a protozoan encounters sunlight and sun- 

 light is harmful to it, it turns away toward a darker 

 part of its habitat. If it encounters an unfavorable 

 chemical stimulus it turns toward a more favorable 

 region. If it encounters food it moves toward it 

 and eats until satisfied. The exact underlying 

 action in these cases is elusive. It is probable that 

 the chemical state of the organism has certain 

 potentialities, and that the exercise of these poten- 

 tialities results in a state of well-being which is 

 favorable, while anything which interferes with 

 them results in a contrary state which causes the 

 withdrawal of the organism from the adverse con- 

 dition. This is not explanation, to be sure, but 

 only a suggestion of what may occur during re- 

 sponse to a stimulus. 



Kepner enlarges upon the prescience of organisms 

 of all kinds in their preparation for future needs 

 through normal development and behavior, and 

 on the ability of animals generally to accept and 

 reject alternatives in securing for themselves the 

 best available environment.^^ While his book is 

 an interesting and stimulating inquiry into this 

 phase of organic activity it leaves us still without 

 a fundamental explanation. We know only that 

 living matter even in the more primitive organisms 

 reacts to environmental stimuli in such a way as 



^ Kepner, W. A., Animals Looking into the FiUure, 1925. 



