I 



Sect. VII. i. i. 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 f 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 occafwnally become obedient to fenfation 

 and to volition. 2. And the fenfual motions. III. 1. Other muf- 

 cular motions are affociated with the irritative ones. 1. And other 

 ideas with irritative ones. Of letters , language, hieroglyphics. 

 Irritative ideas exijl without our attention to them. 



I. r. M. any 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 flomach and bowels by the ali- 

 ment we fwallow ; of the bile-ducts by the bile ; of the kid- 

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

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

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

 mofphere. Thefe motions are accelerated or retarded, as their 

 correfpondent irritations are increafed or diminifhed, without, 

 our attention or confcioumefs, in the fame manner as the vari- 

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

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

 the moiilure 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 fphincfers of the 

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

 ally excited into motion by irritation, for young children make 

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

 cumflances ; " et primis etiam ab incunabulis tenduntur fispi- 

 us puerorum penes, amore nondum expergefael:o." So the nip- 

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

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

 of giving milk to the iips of a child. 



3. The ^tontraclicns of the larger mufclss of our boli.-s, tha,t 

 are molt frequently connected with volition, were originally ex- 

 cited into action by internal irritations : as appears from trie: 

 ^•retching or yawning of all anim?." :r long fieep. In trie 



Vol. L * E nni»g 



