412 DISEASES CLASS IV. 2. 2. 



ORDO H. 



Decreased Associate Motions. 



GENUS II. 

 Catenated with Sensitive Motions. 



IN this genus the sensorial power of association is exerted with 

 less energy, and thence the actions produced by it are less than 

 natural; and pain is produced inconsequence, according to the 

 fifth law of animal causation, Sect. IV. This pain is generally 

 attended with coldness of the affected part, and is seldom suc- 

 ceeded by inflammation of it This decreased action of the se- 

 condary link of the associated motions, belonging to this genus, is 

 owing to the previous exhaustion of sensorial power either in the 

 increased actions of the primary link of the associated motions, 

 or by the pain which attends them; both which are frequently 

 the consequence of the stimulus of something external to the af- 

 fected fibres. 



As pain is produced either by excess or defect of the natural 

 exertions of the fibres, it is not, considered separately, a criteri- 

 on of the presence of either. In the associations belonging to 

 this genus the sensation of pain or pleasure produces or attends 

 the primary link of the associated motions, and very often gives 

 name to the disease. 



When great pain exists without causing any fibrous motions, 

 I conjecture that it contributes to exhaust or expend the general 

 quantity of sensorial power; because people are fatigued by en- 

 during pain, till at length they sleep. Which is contrary to 

 what I had perhaps erroneously supposed in Sect. XXXV. 2. 3. 

 If it causes fibrous motions, it then takes the name of sensation, 

 according to the definition of sensation in Sect. II. 2. 9; and in- 

 creased fibrous action or inflammation is the consequence. This 

 circumstance of the general exhaustion of sensorial power by the 

 existence of pain will assist in explaining many of the diseases of 

 this genus. 



Many of the canals of the body, as the urethra, the bile-duct, 

 the throat, have the motions of their two extremities associated by 

 having been accustomed to feel pleasurable or painful sensations 

 at the same time or in succession. This is termed sensitive as- 

 sociation, though those painful or pleasurable sensations do not 

 cause the motions but only attend them; and are thus perhaps, 

 strictly speaking, only catenated with them. 



