SECT. VIIL 1. x. SENSITIVE MOTIONS. 29 



SECT. VIIL 



OF SENSITIVE MOTIONS. 



I. I . Senfitive mufcular motions were originally excited into aflion 

 by irritation. 2 And Jenfttive fenfual motions, ideas oj imagina- 

 tion^ dreams. H \ . *Senfitive mufcular motions are occajionally 

 obedient to volition. 2. An d fenfittve fenfual motions. III. i. 

 Other mufcular motions are ajfbciated with the fenfitive ones. 2. 

 And other fenfual motions. 



I. i. MANY of the motions of our mufcles, that are excited 

 into aftion by irritation, are at the fame time accompanied with 

 painful or pleafuvable feniations ; and at length become by 

 habit caufable by the fen Nations. Thus the motions of the 

 fphmclers of the bladder and anus were originally excited into 

 adtion by irritation ; for young children give no attention to 

 thefe evacuations ; but as foon as they become fenfible of the 

 inconvenience of obeying thefe irritations, they furTer the water 

 or excrement to accumulate, till it difagreeably afFe&s them j 

 and the action of thole iphinftures is then in conlequence of this 

 difagreeable fenfation. So the fecretion of faliva, which in 

 young children is copiouflv produced by irritation, and drops 

 from 'heir mouths, is frequently attended with the agreeable 

 fenfation produced by the maftication of tafteful food ; till at 

 length the fight of fuch food to a hungry perfon excites into 

 alion thefe falival glands ; as is feen in the Havering of hungry 

 dogs. 



The motions of thofe mufcles, which are affec~ted by lafcivi- 

 ous ideas, and thofe which are exerted in fmiling, weeping, 

 Itarting from fear, and winking at the approach of danger to 

 the eye, and at times the aclions of every large mufcle of the 

 body become caufable by our fenfations. And all thefe motions 

 are performed with ftrength and velocity in proportion to the 

 energy of the fenfation that excites them, and the quantity of 

 fenforial power. 



2. Many of the motions of our organs of fenfe, or ideas, that 

 were originally excited into aclion by irritation, become in like 

 manner more frequently caufable by our fenfations of pleafure 

 or pain. Thefe motions are then termed the ideas of imagina- 

 tion, and make up all the fcenery and tranfa&ions of our 

 dreams. Thus when any painful or pleafurable fenfations pof- 

 fefs us, as of love, anger, fear ; whether in our ileep or waking 

 hours, the ideas that have been formerly excited by the objecls 



of 



