cu. II.] NERVE- ACTIONS, EXTERNAL IMPRESSIONS. 235 



ieir external sensations, and to the pleasure or pain they excite, 

 or to the secondary conceptions they produce. There must be 

 then a sub-element [Merkmal] for the mind in the external 

 sensation of an external impression, so that it feels co-ordinately 

 the reflexion of the latter, and also the force required for 

 the resulting indirect nerve-action; and it is thereby led by 

 the sensational secondary desires to eff'ect the movements 

 volitionally, which then take place the more readily, because 

 the mind can of itself satisfy the desires for volitional movements 

 (283). In this way, the indirect nerve-action becomes at the 

 same time the incidental sentient action of the external sensa- 

 tion excited by the same external impression (97, 221). But 

 having observed, that adapted motions excited after decapitation 

 were always previously volitional, we are led to presuppose 

 that they must be volitional in their nature, and, therefore, 

 always volitional ; and are astonished when we find that they 

 can take place independently of the will. It is so in every 

 instance ; but it is those motions only that excite astonishment, 

 which from their nature we have always been accustomed to 

 consider as wholly dependent on the will. "We are little sur- 

 prised at seeing a muscle in a decapitated animal contract when 

 irritated, because we often feel the irritation without at the 

 same time feeling or observing the contraction; but when we 

 see the animal rise up and leap away when strongly irritated, we 

 are surprised, because a similar sensation was always previously 

 connected with the determination to escape, made by a sensa- 

 tional act of will. If the movement to escape were not always 

 connected with the painful sensation in the uninjured animal, 

 we should see it produced in the decapitated animal without 

 thinking it resembled a volitional movement, and without being 

 surprised. 



439. It is clear from the preceding statements (366, and 

 398 — 401), that brainless animals, although without sensation, 

 because not endowed with mind, nevertheless by means of ex- 

 ternal impressions which operate incessantly in them, perform 

 all the acts and manifest all the activity of the sentient animal ; 

 everything, in short, that is effected sensationally and voli- 

 tionally they effect by means of the organic forces of the 

 impressions ; and since they can act as orderly, judiciously, and 

 rationally as it were, as if they thought, it has been inferred 



