CH. I.] RELATIONS OF IMPRESSIONS. 215 



a single impression, and be combined together by the proper 

 animal force of the body ; although there be neither sensation 

 nor thought, even although the animal possess neither brain 

 nor mind, or, if it possess mind, without the mind in any way 

 influencing the acts. Consequently, the general principles that 



I we shall lay down as to the connection and reciprocal influence 

 bf the two kinds of vis nervosa with and on each other are 

 equally valid, whether or no external impressions be felt or 

 pternal impressions be excited by conceptions. 

 « 399. An external impression is changed into, or develops an 

 internal impression, whenever its course which is naturally 

 towards the brain from the terminating fibrils, is so reflected 

 or turned back, that it returns in the direction from the brain 

 downwards to the branches and terminations of the nerves (32, 

 121). This usually takes place in the brain in animals endowed 

 with cerebral forces, by means of the external sensation of the 

 external impression (129). But since the external impression 

 without either being felt, or without either the presence of the 

 brain or of mind, causes the same movements as are excited by 

 the internal impression of its external sensation (358), it must 

 become a non-conceptional impression without this transition 

 into a sentient action taking place, because it is turned back 

 and reflected in its course to the brain, before it forms the 

 material external sensation in the latter. There are grounds 

 for supposing that this can take place in the brain itself (373, 

 376). In the nerves, however, there is no place in which it can 

 occur, except the ganglia of the motor nerves (14), and at their 

 separation into branches and fibrils (48). According to all 

 probabihty, these ganglia and points of division of the nerves, 

 perform in the motor nerves the office of the brain in relation 

 to the external impressions, since they deflect these from their 

 course upwards, and communicate an internal impression, either 

 to other nerves and their branches, or to different fibrils in the 

 same nerve, conducting in the direction from the brain down- 

 wards ; whereby these twigs and fibrils are suitably stimulated, 

 and such muscular movements excited, as would have been 

 caused if the external impression had reached the brain and 

 had been turned back or reflected from thence by the inter- 

 vention of an external sensation (364, ii). If this reflexion of 

 the external impression be made upon the same efi'erent fibrils, 



