x THE FOEE-BEAIN 633 



In considering the theory of memory, it is important to 

 determine what are the stimuli which are able to revive the 

 memories retained in the ganglion cells of the cortex and to re- 

 invoke the images in the form of representations. In this psycho- 

 physiological process special importance is usually ascribed to 

 internal stimuli, which act upon the sensory organs, constantly 

 excite memories, and bring all the latent energies of the mind into 

 play. But internal stimuli coming from the vegetative organs 

 through the sympathetic system to the cerebral cortex, where they 

 excite bodily sensations and instincts in consciousness, must be 

 of almost equal importance to mental activity. The brain is 

 consequently the meeting-place for impressions from the outer 

 world and for those that originate within the organism. Both these 

 channels excite the psychical centres centripetally and the motor 

 system centrifugally. 



The association between the sense centres and those of instinct 

 give an emotional tone to the perceptions, and thereby increase 

 their dynamic efficiency. The associations between the exterior 

 and interior sensory centres and the psychical areas proper 

 serve the idealisation of the images and determine the exchange of 

 action and reaction between the sensations and instinct, and the 

 intellect. It is in the struggle between impulse and inhibition 

 that actions acquire an ethical character. The greater the 

 functional energy, and the more perfect the inhibition and control, 

 so much the more will reason prevail over emotion. 



By its investigations into the material conditions of human 

 activity, physiology allies itself with the moral sciences. In the 

 twentieth century it will pursue the scientific analysis of psycho- 

 physical phenomena without preconception or prejudice. It will 

 not be hampered as in the past by animus to the concept of 

 the soul, nor, on the other hand, will it fail to recognise that 

 psychical development, even on the ethical side, depends to a 

 large extent upon the soniatic substrate. 



The more science succeeds in revealing the nature of life in 

 general, and of the human mind in particular, the stronger and 

 clearer will be our scientific faith that behind this world of 

 appearances there lies a world of reality, in comparison with 

 which human consciousness and human knowledge are but as a 

 shadow. 



BIBLIOGRAPHY 



For the Historical Development of the Theory of the Structure and Functions 

 of the Brain, see : 



SOURY, J. Le Systeme nerveux central. Paris, 1899. 



The principal Physiological Monographs relating to the Theory of Cerebral 

 Localisation are : 



HITZIG. Untersuchungen liber das Gehirn. Berlin, 1874. Gesammelte Abhand- 

 lungen. Berlin, 1904. 



