THE CEREBRUMj AND ITS FUNCTIONS. 811 



The variety of phases which these different states present is chiefly dependent 

 upon the following elements : (1) the relative degree in which the Mind is in 

 a state of receptivity for external impressions, or is attending only to what 

 passes within itself; (2) the degree in which the coherence of the successive 

 states is maintained by the continuance and right operation of the preformed 

 associations, so that trains of thought are consistently carried out, and reason- 

 ing processes correctly performed ; and (3) the degree in which the normal ope- 

 ration of the intellectual faculties is disturbed by emotional excitement, either 

 general, or limited to one class of feelings. The influence of i^Q first of these 

 elements is remarkably seen in the contrast between natural and artificial Reverie 

 ( 824, 825) ; also between some forms of natural and artificial Somnambulism 

 ( 827) ; and not less between different forms of Insanity, since in this 

 last condition we find some patients constantly brooding over particular trains 

 of thought, and almost incapable of being turned from the contemplation of 

 these by external suggestions, whilst others are no less remarkable for the in- 

 stability of their mental states, and for the readiness with which a new direction 

 may be given to the thoughts by sensory impressions. The influence of the 

 second element is strikingly manifested in the difference between the various 

 phases of the state of Dreaming, and in the contrast between the incoherence 

 of the commoner forms of this, and that consistency in the trains of thought 

 which generally characterizes the state of Somnambulism ; but it is yet more 

 remarkably displayed in those forms of Delirium and Insanity which are es- 

 pecially characterized by the complete confusion of the Intellectual powers, all 

 previous states of consciousness being (as it were) jumbled together, and the 

 order of their recurrence, and the nature of the new combinations which may 

 arise out of them, being irreducible to any principle of .orderly sequence. The 

 influence of the third element is well seen in those forms of artificial Reverie 

 and Somnambulism, in which the feelings as well as the ideas admit of being 

 played upon by external influences ; for it is easy to bring the mind of the sub- 

 ject under the domination of any particular emotion, by taking the appropriate 

 means to excite it j 1 and, so long as this may continue, the language and actions 

 most obviously display its impress. But it is in Insanity that we best see the 

 influence of Emotional states upon the course of thought and of action } for 

 here we find them supplying impulses to bodily action, which the weak- 

 ened Will cannot resist, although the intellect distinctly apprehends the evil 

 consequences of such actions ; or, on the other hand, we find them directing 

 the whole course of mental activity, giving a wrong color to all the ideas which 

 are related to them, and so fixing the attention upon the trains of thought 

 founded upon these, that they come to attain a complete domination over the 

 mind, and hence over the conduct, to which they supply motives of such 

 potency that the Will can neither resist them nor withdraw the mind from at- 

 tending to them. 



835. Thus, then, we see that in all those states in which the directing power 

 of the Will over the current of thought is suspended, the course of action is de- 

 termined by some dominant idea y which for the time has full possession of the 

 mind, and from which the individual has no power of withdrawing his con- 

 sciousness ; the motive power of this idea being such as either impels to action 



antecedent portions of this inquiry, and especially to $$ 804 6, as showing to what ex- 

 tent he regards the organization of the Cerebrum as determining its mode of psychical 

 activity. 



1 We have seen how remarkably the emotions may be played upon, in the "hypnotic" 

 state, by muscular associations (827) ; in the " biologized" state, it is often sufficient to ask 

 the " subject" "Why are you so angry," "Why are you so sad," &c. to induce these 

 conditions respectively, the suggestions being here conveyed verbally, instead of through 

 the muscular sense. 



