REFLEX AND CONDITIONED ACTION 67 



ratus of correlation and learning is incomplete, yet the hypothesis 

 that best fits all of the known facts recognizes variations in the 

 permeability of the synaptic junctions as one important factor in 

 the modification of behavior patterns. The well-known structure 

 of the correlation centers exhibits ample mechanism for diffusion 

 or irradiation of nervous impulses beyond the limits of the cir- 

 cuits traversed by routine reflex responses, for summation and 

 intensification of nervous discharge, and for the collection and 

 redirection of such diffused nervous activity by changes in the 

 internal state of the synaptic junctions involved in such a com- 

 plex feltwork of nervous terminals. The nervous energies which 

 are released within the complicated fabric of neurons and their 

 fibrous processes of which each correlation center is composed 

 apparently form an integrated dynamic system whose manifesta- 

 tions in overt behavior will vary with the fluctuations of the 

 energy discharge within the center. There is every reason to 

 assume that this tissue, like every other protoplasmic structure, 

 is more or less permanently affected by repeated function and so 

 habitual patterns of action tend to be perpetuated. "Practice 

 makes perfect" here as everywhere else. This is the familiar 

 physiological principle of facilitation by use, the organic basis of 

 habit, a principle that holds its own despite the rather uncritical 

 attacks recently made upon it by Hulsey Cason (1924) and others. 

 This dynamic conception of the mode of action of the corre- 

 lation centers presents an intelligible and fairly well-authenti- 

 cated account of the apparatus of stimulus-response physiology 

 and at the same time pictures an organization adequate for en- 

 visaging the total situation as a dynamic "pattern-reaction" 

 with an internal structural configuration correlated with the 

 behavior configuration as this is described in current Hterature 

 of the Gestalt psychology. 



