686 Dynamic Theory. 



ferentiation of organs, or to receive expression. When ideas are 

 evolved which compare favorably with the standard of excellence set up 

 in the brain of the thinker, they are imparted to others, and accepted by 

 them in the same way they accept other ordinary external stimuli. Such 

 stimuli, when delivered to persons of ordinary intelligence, do not stop 

 in the mere differentiation of cells in the tracts of hearing or seeing 

 memories, because, when a person has read the ideas of another, or 

 heard them spoken, it is rare that he remembers the exact words of the 

 author or speaker to the same extent that he remembers his meaning 

 and the general drift of his ideas. These, to a greater or less extent, 

 serve as stimuli to arouse memories of ideas formed previously, and 

 there is an automatic rearrangement and co-ordination between the new 

 and the old, and new nervous elements are differentiated by the newly 

 directed nervous current ; while the attention and the blood supply di- 

 verted from the mere words to the ideas expressed by them, the impres- 

 sion made by the words themselves, is too slight and brief to be perma- 

 nent. If man were a solitary being, a much larger proportion of his 

 organs would be devoted to the memories of original observations alone, 

 but as he is a social animal, the greater area of his cortex is, no doubt, 

 occupied by organs of ideas communicated to him by others. The prin- 

 cipal part of his education consists in cultivating and practicing the 

 habit of appropriating, collating and condensing the ideas which con- 

 stitute the inheritance of the race. The organs differentiated by this 

 process occupy an intermediate ground between the Initial and Terminal 

 organs, and are ever ready to deflect, modify and qualif} T , or neutralize, 

 the stimulations which entering by the former make their way towards 

 the latter. They influence the greater part of our purposive actions. 



The nature of the physiological action, which results in the formation 

 of cortical organs of sense, cannot, of course, be determined positively, 

 but it can be estimated by probable analogies. It is certain that the 

 material for the nourishment and development of the cells is brought in 

 by the blood, and so instant is this dependence of the cells upon the 

 blood that their functions cannot be performed one second after the sup- 

 ply is stopped, as shown in fainting and epileptic fits, and when a stun- 

 ning blow is received upon the head, by which the blood is for a mo- 

 ment expelled from the cerebral arteries. 



Next, we have reason to think that no cell growth occurs except dur- 

 ing the periods of *hyperaemia, or that state of slightly increased activ- 

 ity in the circulation which is brought on in states of attention. These 

 states of attention are brought on b}^ the force of incoming stimuli. 

 The attention is, in fact, an incidental result, and is an indication of 

 the force, the other and principal effects of which are the distension of 



* This word is not used in the pathological sense, in which it signifies an abnormal 

 and diseased condition. 



