The Internal Senses. 695 



gans, so that the stimulation of one may overflow to another and arouse 

 it. As observed elsewhere, our thoughts are constantly flitting from 

 one subject to another. There are two species of this flitting. In one 

 of these, we can, by analyzing a train of thought, discover connecting 

 links all the way through it, and we perceive how we got over from one 

 subject to another apparently very dissimilar one, by means of some el- 

 ement which was common to both. Thus, in a company let one describe 

 a comet as rushing through space like a whirlwind, another will be led 

 to think of the rush of an express train ; another, whose attention is ar- 

 rested by the idea of rushing, will be reminded of having rushed up to 

 a supposed friend on the street, and suddenly discovered him to be a 

 stranger ; and another will remark that a mistaken rush like that might 

 be called a bull-rush. No two objects can be named which have not 

 some element in common. Gravity at least pertains to all, and common 

 colors to a vast variety. The same movements of muscles may be in- 

 volved in two actions belonging to very different categories. But (sec- 

 ond) it often happens that the thought appears to take a leap over a 

 chasm, and we are not conscious of using the bridge, if there be one. 

 The unconscious action of the cerebrum is doubtless accountable for 

 this, and this unconscious action depends upon an accession of blood. 

 The pressure of blood up one artery increases the pressure in all its 

 twigs. As these twigs may supply different organs, it is plain how as 

 soon as one of them by use becomes slightly fatigued, the fresh one 

 breaks out into conscious action, and our thought is, unaccountably to 

 us, transported to a foreign subject. External objects as they come 

 successively before oui* senses, give changing direction to the thoughts, 

 and this is especially the case with children. But when we are quite 

 out of the reach of these influences, these constant shiftings go on 

 through the interaction of the cortical organs alone. We see, therefore, 

 that while the organs may and do act alone, they constitute a family, 

 and may exercise great influence over each other. An undue excite- 

 ment spreads to many of them at once, and under their conflicting re- 

 actions the individual becomes "flustered," or "rattled." 



While the organs may be single in their special functions, they are 

 always more or less associated in action; some of the associations being 

 essential to the complete performance of the action, whether it be one 

 of thought alone, or of one involving muscular movement, while others 

 are merely incidental and unnecessary. Thus, in the composition of an 

 argument, memories located in various parts of the cerebrum must be 

 revived, and in motor action many different motor memories must be in- 

 volved. Incidental ideas constantly show themselves which are of no 

 1 1 so to the argument, and incidental and useless gestures, movements 

 :i!ul tricks constantly accompany c\viy purposive motor movement. The 



