THE NERVOUS SYSTEM AND CONSCIOUSNESS. 153 



to unify all our experiences, an attempt to be able to say that whereas 

 here and here and here my experiences seemed unlike, separate, they 

 now seem alike and conjoined. 



The application of all this to man is plain ; indeed, has been for these 

 past years most impressively operative. Formerly, man was supposed 

 to possess an intellectual and moral nature distinct in kind ; in him was 

 thought to reside a force peculiar, above and beyond all other forces. 

 Observation has had much to say, as many believe, in contravention 

 of these conclusions ; and it is now well known that the doctrine of 

 evolution is brought to bear on all sides of human psychology in a way 

 special and searching. I have not here in mind the work of Spencer 

 or Bain, or their immediate disciples. Within very recent days books 

 have been published which show painstaking research in distinct psy- 

 chological departments. Ribot has discussed the physiology and pa- 

 thology of memory ; Grant Allen has offered help in the " tangled 

 territory " of aesthetics ; Leslie Stephen has written a science of ethics, 

 stating as his purpose, " to lay down an ethical doctrine in harmony 

 with the doctrine of evolution " ; G. H. Schneider, author of a work 

 on the animal will, has just published a careful treatise on the human 

 will from the stand-point of the modern development theory ; Professor 

 Preyer, at Jena, has set out the results of his observations on the soul 

 of the child observations made with greatest care three times each 

 day during the first three years of child-life. I might extend my list 

 at length ; for this there is no need. We are face to face with the 

 question of the relation between brain and consciousness. I have said 

 that this relation is positive and constant, though few, except physi- 

 cians, realize the meaning of such a fact. It means, in the first place, 

 that changes of consciousness coincide with molecular changes in the 

 brain. For every alteration in consciousness, however slight and tran- 

 sient, there has been a molecular change in the brain. This relation 

 means, in the second place, that there is a physical basis for memory. 

 Whether we accept or reject localization of functions in the cerebral 

 hemispheres, we must believe that the cell-modifications which coin- 

 cide with specific sensations remain permanently, thus furnishing a 

 physical, organic requisite for memory. In the third place, this rela- 

 tion means that, in a recollection of any of our experiences, there is 

 presupposed a renewed activity of those very portions of the brain 

 which assisted in the experience. There are no transcendentalists so 

 transcendental that they may transcend this direct relationship between 

 what they are pleased to call gross matter and their sublimest ecstasy. 

 What opinion must we form as to the nature of this relation ? 



We have choice of two conclusions which are alternatives. We 

 may say the relation of brain-matter and consciousness is one of corre- 

 lation, conversion or we may say it is one of instrument to person- 

 ality. Personality is here, as everywhere, a term chosen to represent a 

 series of manifestations so alike among themselves and so unlike all 



