PREFACE 



IN the summer of 1924 I was invited to deliver a 

 course of lectures at the University of California 

 on "Mechanisms of Control of iVnimal Behav- 

 ior." Some of the material there presented is incorpo- 

 rated in this volume. Since that time in attempting to 

 formulate more critically the probable history of the 

 elaboration of cortical functions I naturally restudied 

 Lashley's fundamental experiments on the learning 

 processes of rats. The result was that my entire treat- 

 ment of cortical function in lower mammals was re- 

 cast. This volume is the direct outgrowth of this re- 

 survey of the problem of the cerebral cortex. 



There are two species of mammals whose behavior 

 has been more intensively studied under conditions of 

 laboratory control than any others. These are rats 

 and men. Since one of these stands near the bottom of 

 the mammalian scale and the other represents the 

 culmination of cortical development, it seems appro- 

 priate that our discussion should center about these 

 species and the problems opened up by the facts 

 available regarding their nervous systems in relation 

 to their behavior patterns. 



I have appropriated freely facts and illustrations 

 from the works of others, to whom I wish here to 

 make general acknowledgment in addition to the 

 special references scattered throughout the text. To 

 the courtesy of Henry Holt and Company wc are 



