192 ANIMAL FORCES. [ii. 



358. The external impression on the nerves can produce the 

 same movements in the body as if it were felt, although it is not 

 feltj nor transmitted to the brain. — These movements are 

 animal, inasmuch as they do not result from physical and 

 mechanical forces only (32, 42), (as Haller has shown, particu- 

 larly with reference to muscular movevent (162), (' Physiology,^ 

 § 412). They do not necessarily occur in accordance with 

 conceptions, because the impression is not felt, and, therefore, 

 there are no sentient actions excited by it, that is to say, no 

 actions from external sensations (98, 46); although in the 

 natural condition the two kinds of actions may occur together, 

 and often do (183). Consequently, there are nerve-actions 

 excited by the vis nervosa of the external impression (353), 

 and whether the external sensation of the mind co-operates 

 with it, or not. 



359. If a nerve, ordinarily stimulated to excite certain 

 movements, by conceptional impressions^ acting on its 

 origin in the brain, be stimulated at its origin by other 

 internal impressions which are not material ideas (121) ; or if 

 its medulla be irritated by some other internal impression, at 

 any point of its course downwards, after its connection with its 

 cerebral origin, or with the brain generally, has been severed, 

 either by ligature or division of the nerve, or by the separation 

 of the head from the body, — in either case the same move- 

 ments are excited (provided animal life continues, and with the 

 other conditions previously stated, § 357), by the internal im- 

 pression simply, as are usually excited by internal impressions 

 caused by conceptions. This is also an irrefragable principle, 

 and is of tbe greatest importance in understanding the doc- 

 trines to be taught in this second part. In the Second Section 

 of the Third Chapter, abundant examples will be given of the 

 action of the vis nervosa of the internal impression : we can 

 here give only some of the most prominent. If the nerve 

 of a limb be irritated with a needle, movements take place 



• By the term internal impressions of conceptions, Unzer means to express the 

 material ideas or changes which take place at each act of mind in the hrain, and 

 which are referred to in the First Part (§ 121, foot-note, et alia). For brevity's 

 sake, I have termed these impressions conci^ ^iowa/, becanse I have already translated 

 Vorstellung by conception ; but it is of importance to remember the wide and in- 

 definite meaning attached to the term. {Vide § 25.) — Ei' 



