312 ANIMAL NATURE AS A WHOLE. [in. 



means of its vis nervosa (373, 374), and not by the animal- 

 sentient forces. But, on the other hand, when the latter act 

 on the body, they are excited into action by the conceptive 

 force (Baumgarten's ^Metaphysics', § 554). 



607. The vis nervosa is distributed to every portion of a 

 nerve (31). The seat of the animal-sentient forces is in the 

 brain, or the nerves dependent on it (25). The seat of the 

 animal-moving forces in insentient animals is in their nervous 

 system, and this is the case with sentient animals, in so far as 

 they also possess the nature of the insentient. But the seat of 

 the animal-moving forces of sentient animals, peculiarly as such, 

 is in the brain, the seat of mind (10). 



608. All the animal movements of an insentient animal Eire 

 dependent on the vis nervosa, and all the animal acts take 

 place according to its laws of action. This is the case also with 

 sentient animals, in so far as their movements are dependent 

 on the vis nervosa; but in so far as they are sentient actions of 

 those conceptions which the conceptive force forms and de- 

 velops in the mind, according to psychological laws, indepen- 

 dently of the vis nervosa, they flow from the cerebral forces, 

 which the conceptive force regulates (6). But if the movements 

 be both sentient actions and nerve-actions, they follow the 

 laws of both kinds of forces acting in co-operation (Part II, 

 Chap. IV, Sect. in. Compare also § 579). 



609. Insentient animals are moved animally by the vis ner- 

 vosa of external or internal impressions, according to their 

 nature (31, 32, 121). The external impressions act upon them, 

 either by means of direct nerve-actions (418), or indirect; when 

 they are reflected in the ganglia, or points of division of the 

 nerves, along which they pass upwards upon other nerves, and 

 thereby put the organs to which the latter are distributed into 

 motion (419, 421). Nature herself causes in insentient animals 

 such external impressions as are necessary to the maintenance 

 in them of those animal acts on which their preservation and 

 the objects of their existence depend; and to this end their 

 animal acts are as adaptively excited, arranged, and connected 

 with each other, as in sentient animals by means of their 

 natural instincts (435 — 439), although neither the sentient nor 

 insentient act from consciousness (266). The natural primary 

 internal impressions, in insentient animals, excite those move- 



