SECT, VII. i. r. IRRITATIVE MOTIONS. 25 



SECT. VII. 



OF IRRITATIVE MOTIONS. 



I. I. Some mufcular motions are excited by perpetual irritations* 2. 

 Others more frequently by fenfations. 3. Others by volition. 

 Cafe of involuntary Jl retchings in paralytic limbs. 4. Some fen- 

 fual motions are excited by perpetual irritations. 5. Others more 

 frequently by fenfation or volition. II. I. Mufcular motions ex- 

 cited by perpetual irritations occajionally become obedient to fenfation 

 and to volition. 2. And the fenfual motions. III. I. Other muf- 

 cular motions are officiated with the irritative ones. ' 2. And other 

 ideas with irritative ones. Of letter s> language , hieroglyphics. 

 Irritative ideas exift without our attention to them. 



1. i. MANY of our mufcular motions are excited by perpet- 

 ual irritations, as thofe of the heart and arterial fyftem by the 

 circumfluent blood. Many other of them are excited by inter- 

 mitted irritations, as thofe of the ftomach and bowels by the ali- 

 ment we fwallow \ of the bile-du6ts by the bile ; of the kid- 

 neys, pancreas, and many other glands, by the peculiar fluids 

 they feparatc from the blood ; and thofe of the lacteal and oth- 

 er abforbent vefTels by the chyle, lymph, and moifture of the at- 

 mofphere. Thefe motions are accelerated or retarded, as their 

 correfpondent irritations are increafed or diminifhed, without 

 our attention or confcioufnefs, in the fame manntr as the vari- 

 ous fccretions of fruit, gum, refin, wax, and honey, are produ- 

 ced in the vegetable world, and as the juices of the earth and 

 the moifture of the atmofphere are abforbed by^ their roots and 

 foliage. 



2. Other mufcular motions, that are mod frequently con- 

 nected with our fenfations, as thofe of the fphindters of the 

 bladder and anus, and the mufculi ereciores penis, were origin- 

 ally excited into motion by irritation, for young children make 

 water, and have other evacuations without attention to thefe cir- 

 cumftances , " et primis etiam ab incunabulis tjenduntur faepi- 

 us puerorum penes, amore nundum expergefaclo." So the nip- 

 ples of young women are liable to become turgid by irritation, 

 long before they are in a fituation to be excited by the pleafure 

 of giving milk to the lips of a child. 



3. The contractions of the larger mufcles of our bodies, that 

 are moil frequently connected with volition, were originally ex- 

 cited into a&ion by internal irritations : as appears from the 

 ii retching or yawning of all animals after long fleep In the 



VOL. I. E beginning 



