282 PHYSICAL EXPRESSION. 



principles of analysis to both functions. It may 

 be I think it is true that external forces, or the 

 environment, do often bring about the special 

 combinations and sequences of trophic action and 

 kinetic action ; and I imagine that here we have 

 an important factor in the process of evolution of 

 the individual and of the species. 



Forces afferent to the subject may alter the 

 succession of a kinetic series or the succession of 

 a trophic series. 



A child is at play, showing us much spontaneous 

 movement and many reflex actions ; speak to the 

 child the sound of your voice totally alters the 

 character of his movements ; the series of his kinetic 

 actions is altered by the afferent force, your voice. 



If a branch of vine be placed in darkness it will 

 grow in abnormal porportions, with long internodes 

 and small leaves, but will bear fruit. The propor- 

 tional trophic series in the vine is altered by the 

 action of light or darkness. It appears to me that 

 often it is easier to observe this in the kinetic 

 functions, than in the trophic functions. I believe, 

 also, that very often in organic nature, plants and 

 brains, a trophic action indicated by permanent 

 impressionability does occur upon each display of 

 kinetic function, and that this is the explanation of 

 movements becoming automatic. 



If this theory be true, it may be put to the test 

 by my experimental methods. I believe that a 

 subject may, as the result of its vital properties and 

 nutrition, display the two functions T = trophic 

 action, K = kinetic action; but, however much 



