NERVOUS INTEGRATIONS IN MAN 263 



that is a reflex innate and characteristic of the species. 

 But a dog customarily fed by the same person may secrete 

 sal va when it sees that person come at the accustomed time. 

 This latter is a reaction for which it has been shown the 

 cortex is needful. The cortex has the means of attaching 

 the reactive act, e.g. sahvation, innately resulting from a 

 particular stimulus, e.g. food in the mouth, to another 

 stimulus, e.g. visual image of a platter, if this latter stimulus 

 has occurred for even a few times closely precurrent to the 

 innately eff"ective one. Individual experience with its repeti- 

 tions during daily life of stimuli habitually closely associated 

 in time finds the cortex therefore an educable nervous 

 organ, by which the organism acquires numbers of adapted 

 reactions meeting the vicissitudes of the environment. 

 Man experiencing these reactions in himself is aware that 

 accompanying these adapted and adaptable trains of acts 

 and behavior there occur in him mental events which he 

 distinguishes in some measure one from another as memorial, 

 ■ aff"ective, conative, etc. This mental activity is so important 

 to man that from our point of view it would seem the 

 coping stone of the integration of the individual. It is there- 

 fore to the psychologist we must turn for fuller study of the 

 final contribution made by the nervous system to the 

 integration of man. 



But to pass from a nerve impulse to a psychical event 

 is to step as it were from one world to another. We might 

 expect then that at the places of transition from its non- 

 mental to its mental regions the brain would exhibit some 

 striking change of structures. But no; in the mental parts 

 of the brain still nothing but the same old structural ele- 

 ments, with essentially the same old features, set end-to-end 

 in neurone chains as elsewhere, and evidently just as before 

 serving as lines for travel of nerve impulses, and nodal 

 points for their convergence and irradiation, their further 

 launching by excitation, and their restriction by inhibition. 

 We are here faced in perhaps its sharpest form with the 

 age-old ever unsolved problem of the nexus between matter 

 and life and mind. 



