CH. III.] EXTERNAL SENSATIONAL ACTIONS. 99 



never a nerve-action ; 2, that the movement, which is a nerve- 

 action, is never a sentient action of external sensations; for 

 there is nothing more certain than that a sentient action result- 

 ing from external sensations may be at the same time a nerve- 

 action, and vice versa. On the other hand, there may be 

 nerve-actions in the mechanical machines, which are not, at the 

 same time sentient actions, nor resulting from external sensa- 

 tions, because the external impression is prevented developing 

 a material sensation by a natural or other obstacle (47, 48, 199). 

 Thus, the movement of the heart is usually a nerve-action only, 

 and seldom a sentient action (167), for we but rarely feel the 

 external impression which excites the movement, although we 

 often feel the stroke itself, which is the nerve-action. — (Com- 

 pare §225.) It is not necessary to inquire here, whether there 

 be sentient actions in the mechanical machines from external 

 .sensations which are not also nerve-actions. 



184, i. When an external impression on the nerves is not 

 ^felt, then the movement which it causes in the machines is 

 ^not a sentient action from an external sensation. If, however, 

 the movement itself be felt, and this acts as an external sen- 

 sation in exciting new movements, the latter are sentient 

 ^actions from the external sensation produced by a nerve- 

 faction (183, 443). 



ii. It is not manifest what influence is exercised by feeling, 



|iOr the consciousness of an impression in the production of 



Jsentient actions which can also be simply nerve-actions, more 



.than by the external impression itself; unless it be that the 



■actions are rendered more complete and regular when the two 



:CO-operate. Generally, however, the feeling or consciousness 



;of the external impression seems to have no other object than 



to excite other conceptions in the mind, and other sentient 



factions, so that its operation is extended evidently through the 



organism generally, and becomes of compound utility. For 



example, if the movement of the stomach when empty from 



fasting, remain such as it really is, — a nerve-action, — and be 



f.not a sentient action at the same time, the desire cannot be 



j^excited which we term hunger, and the organism is neglected. 



(If a violent spasm of a muscle were a nerve-action only, and 



fnot also a sentient action from pain, the functions of the muscle 



.might be destroyed without our taking any steps to prevent it. 



