30 BIOLOGY AND SOCIAL PROBLEMS 



as a shadow of the past. What memory really 

 is, however, is rather a matter for investiga- 

 tion than speculation. Of one thing we can 

 be fairly certain, memory is not a general 

 property of the nervous system, but is an op- 

 eration carried on in the cerebral cortex. 



This portion of the brain is also the part 

 concerned with that second set of operations 

 which seem to result from the disintegration 

 of simple reflexes, namely, the voluntary acts. 

 That the impulses to voluntary movements in 

 man take their course from the cerebral cortex, 

 over definite neurone tracts through the cord 

 and nerves to the muscles concerned, is a fact 

 well attested by anatomy, pathology, and the 

 study of cortical localization. But it is not my 

 purpose to undertake to trace out the nervous 

 mechanism by which we control that enor- 

 mous complication of musculature that moves 

 when we wish to move, and that fails to act 

 when by reason of accident or disease nerve 

 tracts are interfered with or destroyed. Suffice 

 it to say that the impulses for the multitude 

 of our voluntary acts emanate from the cortex. 

 Whether they originate there de novo, or are 

 some delayed overtime sensory impulses mak- 

 ing their way deliberately through the central 



