i6o NATURE AND MAN. 



4. That the cerebrum is the seat of the formation of ideas, or 

 elementary notions originating from sensations, and of all those 

 higher intellectual operations^ of which those ideas form (as it were) 

 the pabulum. 



5. That the occurrence of ideas in the cerebrum may produce 

 feelings of pleasure or pain in the sensory ganglia, analogous to 

 those which are produced by sensations. 



6. That the tendency to the recurrence of a certain class of 

 ideas, constantly connected with feelings of pleasure or pain, con- 

 stitutes what is known as an emotion, desire, or propensity ; and 

 that this is composite in its nature, involving the cerebrum for the 

 formation of ideas, and the sensory ganglia for the feelings with 

 which they are associated. 



7. That certain ideas, which thus strongly excite the feelings, 

 may also produce m.otions through the instrumentality of the 

 sensory ganglia and their nerves ; that these movements are in- 

 voluntary in their character, and are excited by emotional states 

 in the same manner as they are by direct sensations ; and that 

 they consequently belong to the consensual group. 



8. That intellectual operations may take place, in which the 

 feelings do not participate (as, for example, in mathematical or 

 scientific ratiocination) ; but that the motives which regulate our 

 personal conduct are, in great part, derived from the feelings 

 attached to particular ideas or classes of ideas. When the 

 emotional states thus act, in affecting the further course of the 

 mental operations, they have no immediate agency upon the body, 

 their influence being exerted through the will. 



9. That the exertion of the reasoning powers, and the final 

 determination which, in its action on the body or the mind, we 

 call volition or will, operates solely through the instrumentality of 

 the cerebrum. 



10. That the cerebrum has probably no direct connection, 

 however, either with the sensory organs or with the muscular 

 system; but that it depends upon the sensorial ganglia for the 

 reception of sensations, and for the execution of voluntary move- 

 ments ; this execution being still guided by the sensations received 

 through these ganglia, and the act of muscular contraction being 

 dependent upon their continuance. 



