Law of Proenvironment 24 1 



out the entire series of the higher Metazoa. For most of thi 

 responses or actions shown by such animals are wholly due 

 to efferent proenvironal stimuli which start as summated 

 responses to simpler stimuli that have passed in from ^^thout, 

 and which guide — we might almost say impel — each animal 

 along definite pathways. 



But in all such proenvironal nerve responses the gradual 

 evolution of a motor and of an inhibitory nervous system 

 must constantly be kept in view as a great evolving zoological 

 principle. Accordingly all afferent stimuli from without that 

 affect any nerve cell have been termed receptory; all stimuli 

 that originate from such receptories either as direct or as sum- 

 mated responses toward action effectory; and all stimuli that 

 are reducing, canceling, or contrary factors to the last in- 

 hihitory. 



It would be impossible to deal with the comparative relation 

 of the effectory and the mhibitory now. But, on the grounds 

 already advocated (p. 208), namely that each proenvironal 

 act brings about a temporarily "satisfied" state in an organ- 

 ism, if we may judge from frequent human behavior and from 

 not a few acts of the lower animals, it must often happen and 

 have happened that a certain summated act, resulting from 

 several environal stimuli, may have originated a "satisfied" 

 state, but yet that one or more of the constituent stimuli may 

 have been helpful and upbuilding, another more or less injuri- 

 ous and disintegrating. By frequent and slow responses, in 

 which all such acts were tested, a course or pathway would 

 be ultimately plotted, so that different groups. of animal organ- 

 isms would gradually reach a phase of development in which 

 the "satisfied" but disintegrating stimuli would be subsidiar- 

 ized to the "satisfied" but upbuilding, as these were com- 

 pounded into summated action. The converse as well as a 

 balanced state would equally hold true. 



If we may borrow an illustration at tliis stage of our studies 

 from human history, it can truly be said that the surviving 

 and even dominant nations of today are largely those who have 

 subsidiarized "satisfied" but disintegrating responses or unsat- 



