SECT. XXXV. i. DISEASES OF ASSOCIATION. 503 



more eafily lofe them again, as fhewn in Se&ion . 

 XXXI. on Temperaments. 



When the beginning of fuch a train of actions be- 

 comes by any means difordered, the fucceeding pare 

 is liable to become disturbed in confequence, and 

 this is commonly termed fympathy or confent of 

 parts by the writers of medicine. For the more 

 clear undemanding of thefe fympathies we mult 

 confider a tribe or train of a&ions as divided into 

 two parts, and call one of them the primary or 

 original motions, and the other the fecondary or 

 fym pathetic ones. 



The primary and fecondary parts of a train of 

 irritative a&ions may reciprocally affe& each other 

 in four different manners, i. They may both be 

 exerted with greater energy than natural* 2. The 

 former may aft with greater, and the latter with 

 lefs energy. 3. The former may aft with lefs, and 

 the latter with greater energy. 4. They may both 

 act with lefs energy than natural. I fhall now give 

 an example of each kind of thefe modes of adhon, 

 and endeavour to mew, that though the primary 

 and fecondary parts of thefe trains or tribes of mo- 

 tion are conne&ed by irritative affociation, or their 

 previous habits of acting together, as defcribed in 

 Sect. XX. on Vertigo. Yet that their a&ing wLh 

 fimilar or diffimilar degrees of energy, depends on 

 the greater or lefs quantity of fenforial power, which 

 the primary part of the train expends in its exer- 

 tions. 



The actions of the ftomach conftitute fo important 

 a part of the affbciaiions of both irritative and fen- 

 fitive motions, that it is faid to fympathize with 

 alrnoft every part of the body; the firft example, 

 which I ffiall adduce to fhew that both the primary 

 and fecondary parts of a train of irritative affocia- 

 tions of motion ael with increaled energy, is taken 

 from the confent of the fkin with this organ. When 



the 



