SECT. VII. i. IRRITATIVE MOTIONS. 39 



and arterial fyftem by the circumfluent blood- 

 Many other of them are excited by intermitted ir- 

 ritations, as thofe of the ftomach and bowels by the 

 aliment we fwallow ; of the bile-ducts by the bile ; 

 of the kidneys, pancreas, and many other glands, 

 by the peculiar fluids they feparate from the blood ; 

 and thofe of the lacteal and other fubfequent veflels 

 by the chyle, lymph, and moifture of the atmofphere. 

 Thefe motions are accelerated or retarded, as their 

 correfpondent irritations are increafed or diminifhed, 

 without our attention or confcioufnefs, in the fame 

 manner as the various fecretions of fruit, gum, re- 

 fin, wax, and honey, are produced in the vegeta- 

 ble world, and as the juices of the earth and the 

 mpifture of the atmofphere are abforbed by their 

 roots and foliage. 



2. Other mufcular motions, that are moft fre- 

 quently connected with our fenfations, are thofe of 

 the fphincters of the bladder and anus, and the muf- 

 culi erectores penis, were originally excited into 

 motion by irritation, for young children make wa- 

 ter, and have other evacuations without attention 

 to thefe circumftances ; " et primis etiam ab incu- 

 nabulis tenduntur faepius puerorum penes, amore 

 nondum expergefacto." So the nipples 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 mod frequently connected with 

 volition, were originally excited into action by in- 

 ternal irritations : as appears from the ftretching or 

 yawning of all animals after long fleep. In the be- 

 ginning of fome fevers this irritation of the mufcles 

 produces .perpetual ftretching and yawning ; in 

 other periods of fever an univerfal reftleflhefs arifes 

 from the fame caufe, the patient changing the at- 

 titude of his body every minute. The repeated 



ftruggles 



