322 BRAINS OF RATS AND MEN 



the latter requires a greater blood supply than does 

 growth. The granular and supragranular cortex (lay- 

 ers I-IV of Brodmann, see p. 88) are more richly 

 vascularized than is the infragranular cortex, a point 

 of interest in view of Bolton's (1914) view that the 

 higher cortical functions are served chiefly by the 

 supragranular layers. 



We have no data on the vascularity of the human 

 cerebral cortex which can be compared with Craigie's 

 observations on the rat. From the evidence at hand 

 it seems probable that the amount of vital energy ex- 

 pended is greater in the case of complex associations 

 than in smoothly running reflexes and automatisms. 

 And this energy is derived from consumption of tissue 

 in the case of brain work just as truly as in the case 

 of muscular work. 



Human effort, then, may take two forms. The 

 first is the performance of physiological work with 

 expenditure of much energy and the drawing off of 

 non-specific bodily reserves (of peripheral and cerebel- 

 lar type), all by virtue of a surpassingly complex and 

 efficient internal organization which is stabilized and 

 stereotyped so that it operates efficiently and either 

 uniformly (as in reflex) or by trial-and-error selection 

 of the adaptive response from among a limited rep- 

 ertoire of available reflex patterns. There is no oc- 

 casion for consciousness in this form of activity; there 

 is effort but no volition. 



The second form of efl^ort is best seen in that be- 



