CHAPTER III. 



ON SOME GENERAL CONDITIONS OF BRAIN-ACTIVITY. 



The elementary properties of nerve-tissue on which 

 the brain-functions depend are far from being satisfactorily- 

 made out. The scheme that suggests itself in the first 

 instance to the mind, because it is so obvious, is certainly 

 false: I mean the notion that each cell stands for an idea 

 or part of an idea, and that the ideas are associated or 

 'bound into bundles' (to use a phrase of Locke's) by the 

 fibres. If we make a symbolic diagram on a blackboard, 

 of the laws of association between ideas, we are inevitably 

 led to draw circles, or closed figures of some kind, and to 

 connect them by lines. When we hear that the nerve-cen- 

 tres contain cells which send off fibres, we say that Nature 

 has realized our diagram for us^ and that the mechanical 

 substratum of thought is plain. In some way, it is true, out 

 diagram must be realized in the brain ; but surely in no 

 such visible and palpable way as we at first suppose.* An 

 enormous number of the cellular bodies in the hemispheres 

 are fibreless. Where fibres are sent off they soon divide into 

 untraceable ramifications ; and nowhere do we see a simple 

 coarse anatomical connection, like a line on the black- 

 board, between two cells. Too much anatomy has been 

 found to order for theoretic purposes, even by the anat- 

 omists ; and the popular-science notions of cells and fibres 

 are almost wholly wide of the truth. Let us therefore rele- 

 gate the subject of the intimate workings of the brain to 



* I shall myself in later places indulge in much of this schematization. 

 The reader will understand once for all that it is symbolic; and that the 

 use of it is hardly more than to show what a deep congruity there is between 

 mental processes and mechanical processes of some kind, not necessarily of 

 the exact kind portrayed. 



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