CH. III.] REPOSE AND EXHILARATION. 153 



volitional movements, must have been such formerly, or will 

 be for the future, or are such in any other creature. 



The Instinct for Repose and Exhilaration, 



287, i. The animal-sentient forces are exhausted by long 

 activity, and the destruction of the animal would result there- 

 from if nature had not previously provided against this cause of 

 exhaustion. When the animal-sentient forces (that is to say, 

 the forces of the material ideas, as they may be now considered, 

 in so far as they cause conceptions or sentient actions,) have 

 been uninterruptedly used by the animal for so long a time 

 that any further effort would be injurious, it feels during 

 thought or during the performance of the sentient actions in 

 the body an unpleasant difficulty, which has been termed lassi- 

 tude, weariness, ov fatigue (280). This unpleasant sensation is 

 the natural stimulus of the instinct for repose or sleep, which 

 instinct consists in an effort to develop the contrary to this 

 unpleasant sensation, that is, the withdrawal of the mind from 

 the wearying thoughts, and letting the animal-sentient forces 

 be inactive, so as to experience the sweetness of repose, and 

 thereby collect new forces, as is the design of the Creator in 

 the instinct and its object with the animal, although the latter 

 knows nothing of the actual intent, namely, the renewal of the 

 strength (266) . Everything which causes the unpleasant sensation 

 of lassitude develops the sensational stimulus for repose, and the 

 instinct itself, the longing for repose. Causes of this kind are 

 hardships, every long-continued movement, meditation, and all 

 long-continued thought, attention, reflection, and abstraction {77) ; 

 also articles of food, or medicines, which interrupt the animal-sen- 

 tient forces, as wine, opium, heavy meals, pressure in or upon the 

 brain, the plethoric state, various poisons, and numerous others. 

 The sensational stimulus, namely, the disagreeable external 

 sensation of weariness, manifests its sentient action in the car- 

 diac and respiratory movements (271), which are at first languid 

 almost to faintness ; but in a higher degree the stimulus becomes 

 feverish, and these actions become contra-natural (276, iv. See 

 also Haller ^ Physiology,^ § 580). In so far as the sensational 

 stimulus is a foreseeing of the future sweet repose (the contrary 

 to the disagreeable feeling of lassitude), it manifests its sentient 



