288 ANIMAL FORCES. [ii. 



it appears that the incidental sentient actions of the instinctive 

 actions, stand in the same relation, and may be equally excited 

 by the vis nervosa. All the actions which a sentient animal 

 performs under the influence of the instinctive passions (299 — 

 303, &c.), may be excited in another animal by the vis nervosa of 

 external impressions in the order and succession preordained 

 by nature. Decapitated insects supply illustrative examples. 

 In many animals these actions take place naturally as nerve- 

 actions. 



563. That the sentient actions of the passions can be excited 

 as nerve-actions, by means of non-conceptional internal im- 

 pressions, does not admit of doubt (503). All the passions 

 modify the circulation, the action of the heart, the respiration, 

 and the vital movements in general (307, 310). Internal im- 

 pressions do the same in a thousand instances, simply by means 

 of the vis nervosa (515 — 521, 525). The other sentient actions 

 of the passions are often volitional movements, often changes 

 in the natural functions of the viscera (307 — 325), and these 

 also can be produced by the vis nervosa of internal impressions 

 (508, 532 — 540). But an important question arises, whether the 

 sentient actions of a passion, considered as incidental actions 

 of the primary external sensation, can be excited by the vis 

 nervosa of the external impression proper to the latter, according 

 to the doctrines stated, § 544. 



564. Animals not endowed with reason are peculiarly main- 

 tained in the performance of their natural functions by the 

 blind instincts ; and it is only the most skilful in which we see 

 the latter attain to the stage of instinctive passions, because 

 their brain is capable of containing a greater number or a 

 greater development of material ideas (26); for it is certain, 

 that a more perfect conceptive force which can form wholly 

 pure conceptions and a higher degree of sensational perceptions, 

 are necessary to the development of the passions in general 

 (305), and these are possessed only by the more perfect animals. 

 A true passion never results so directly from external sensations, 

 however pure [klar] they may be, as the natural instincts and 

 instinctive passions (276, i, 298). The former usually require 

 entire series of other pure [klar] sensational conceptions, often 

 only distantly related to external sensations, which the mind 

 connects together according to psychological laws, and of w^hich 



