SECT. IX. i. i. VOLUNTARY MOTIONS. 31 



SECT. IX. 



OF VOLUNTARY MOTIONS. 



I. I . Voluntary mitfcitlar motions are originally excited by irritations. 

 2. And voluntary ideas. Of reafon. II. I. Voluntary mufcular 

 motions are occasionally can fable by fenfations. 2. And voluntary 

 ideas. III. I . Voluntary mufcular motions are occafionally obe- 

 dient to irritations. 2. And voluntary ideas. IV. I. Volun- 

 tary mufcular motions are ajfociated with other mufcular motion:. 

 2. And voluntary ideas. 



WHEN pleafure or painafFeft the animal fyftem, many of its 

 motions both mufcular and fenfual are brought into aftion ; as 

 v/as (hewn in the preceding fefcion, and were called fenfitive 

 motions. The general tendency of thefe motions is to arreft 

 and to poffefs the pleafure, or to diflodge or avoid the pain : but 

 if this cannot immediately be accomplished, defire or averfion is 

 produced, and the motions in confequence of this new faculty 

 of the fenforium are called voluntary. 



1. i. Thofe mufcles of the body that are attached to bones, 

 have in general their principal connexions with volition, as I 

 move my pen or raife my body. Thefe motions were original- 

 ly excited by irritation, as was explained in the fe&ion on that 

 fubjecl, afterwards the fenfations of pleafure or pain, that accom- 

 panied the motions thus excited, induced a repetition of them ; 

 and at length many of them were voluntarily pra&ifed in fuc- 

 ceflion or in combination for the common purpofes of life, as 

 in learning to walk, or to fpeak ; and are performed with 

 ftrength and velocity in proportion to the energy of the volition, 

 that excites them, and the quantity of fenforial power. 



2. Another great clafs of voluntary motions confifts of the 

 ideas of recollection. We will to repeat a certain train of ideas, 

 as of the alphabet backwards ; and if any ideas that do not be- 

 long to this intended train, intrude themfelves by other connex- 

 ions, we will to rejecl them, and voluntarily perlift in the deter- 

 mined train. So at my approach to a houfe which I have but 

 once vifited, and that at the dittance of many months, I will to 

 recollect the names of the numerous family I expert to fee there, < 

 and I do recollecT: them. 



On this voluntary recollection of ideas our faculty of reafon 

 depends, as it enables us to acquire an idea of the diflimilitude 

 of any two ideas. Thus if you voluntarily produce the idea of 

 a right-angled triangle, and then of a fquare ; and after having 



excited 



