I 3 o OF MIND. 



mechanism or other thing in this world capable of working 

 or acting. 



OF MENTAL NERVOUS ACTION.* 



After the admissions I have been obliged to make of the 

 failure of attempts to demonstrate the mere structure of 

 comparatively simple nerve organs, it may seem almost a 

 waste of time to venture upon the consideration of the action 

 of the highest and most complex of them all ; but, in fact, 

 opinions have been formed and conclusions have been 

 arrived at upon the subject. There can be little impro- 

 priety, therefore, in enquiring what is the general conception 

 of mental nerve action to be derived from contemplating 

 the structure and arrangement of the tissues concerned, as 

 far as these have yet been elucidated, in conjunction with 

 a careful consideration of important general facts and prin- 

 ciples discovered in studying other and less complex nerve 

 phenomena. 



There can be no doubt that the most important part of 

 the mechanism engaged in mental action is situated in the 

 grey matter of the cerebral convolutions ; and the results of 

 observations upon the structure, as well as experiments 

 upon the action of other nerve organs, justify us in the con- 

 clusion that nerve-cells consisting of germinal matter and 

 formed material, and nerve fibres composed of formed 

 material only, are the active agents. These are so arranged 



* It is hoped that the new facts and observations recorded in this 

 section will, in some slight degree, atone for the occasional introduction 

 of what will now be regarded by many modern authorities an obsolete 

 metaphysic. 



