THE PSYCHIC BRAIN CELLS 325 



It may well be dependent on some such histological 

 increase of the psychic stratum of neurons, that the 

 lessening, or shrinkage, of the, sensory, and motor, strata, 

 of the cerebral matrix, is " made up for," or structurally 

 substituted, and that the increase in extent of intelligence, 

 and depth of knowledge, is sustained, until such time, 

 as senile changes begin mentally to manifest themselves, 

 or as involution seizes on the materio-psychic being, and 

 " closes the scene." 



