CH. IV.] RELATION OF CEREBRAL & NERVE FORCES. 303 



resulting from either are only nerve-actions, since they cannot 

 be also at the same time sentient actions (97), and there are 

 no other animal forces than the vis nervosa (356), inasmuch as 

 in this case it does not signify, whether the unfelt external im- 

 pression can be felt or not ; or whether the primary internal 

 impression not caused by conceptions can be caused by con- 

 ceptions or not. It follows, that no combined action of the 

 cerebral forces and vis nervosa effects these animal movements, 

 even in sensational and thinking animals, and a fortiori in those 

 which have no sensational faculty, and, consequently, no mind. 

 Since the latter class, in common with all animals, without 

 exception, are endowed at least with the vis nervosa, it alone 

 must be sufficient for all the objects of their existence. According 

 to this view, the acts of all anencephalous [hirnlosen] animals 

 (to all which, as far as can be observed, they are excited by 

 external impressions), are partly direct nerve-actions, partly 

 dependent on the reflexion of the impressions in the ganglia 

 and plexuses, and thereby are rendered similar to sentient 

 actions and volitional acts (438-439) ; while, on the other hand, 

 their vital movements and the indispensable functions of their 

 mechanical machines, are maintained by non-conceptional im- 

 pressions, as occurs in sensational animals (515, 519, 525, 532). 

 These views apply also to the acts of sensational animals, in as 

 far as the impressions which excite them are unfelt, or not 

 induced by conceptions, for as they all possess the two kinds 

 of vis nervosa, the acts must necessarily be nerve-actions, inas- 

 much as the mind cannot act (353, 356). 



591. When an external impression is felt, the resulting 

 animal movements are both nerve-actions of its vis nervosa and 

 sentient actions of its external sensations. The first — because 

 they equally result, even if the sensation be wanting (542 — 547): 

 the last — because the sensation of an external impression 

 excites material ideas at the cerebral origin of the sensitive 

 nerves; the internal impression thus caused is transmitted down- 

 wards, and excites movements in those machines to which the 

 nerve is distributed, and these are the direct sentient actions of 

 the external sensation, and identical with the direct or indirect 

 nerve-action of the external impression, which gave rise to the 

 sensation (418, 419, 358). But since the transmission of the 

 internal impression, caused })y a material external sensation. 



