320 BRAINS OF RATS AND MEN 



and material which has been accumulated through- 

 out the entire preceding course of life, in short, the 

 totality of our experience, can be drawn upon and 

 made immediately available on demand. It is the 

 whole personality that reacts to meet every situation 

 (Carr, 1925, p. 343). 



The biological reserves which are thus expended 

 may be considered from two standpoints: first, the 

 energetics of the process; and, second, the patterns in 

 which the energies are released. The end-results of 

 the second factor can in some cases be observed di- 

 rectly in the study of overt behavior. The investiga- 

 tion of the energy transformations involved is a much 

 more recondite matter. 



All living substance in the resting condition has 

 some unexpended potential energy. In the nervous 

 system there is much accumulation of this sort, laid 

 down in a characteristic iron-containing nucleopro- 

 teid which is chemically unstable, the chromophilic 

 substance, or "Nissl bodies." The oxidation of this 

 intracellular material may liberate energy rapidly 

 where it will do the most good (Herrick, 1924, pp. 

 108, 256). 



The amount of blood supplied to various parts of 

 the body is roughly proportional to the rates of 

 metabolism or chemical change characteristic of those 

 parts. The number of blood vessels or the density of 

 the capillary network in various parts of the brain 

 can, therefore, be taken as an approximate quantita- 



