Lii. III.] ACTIONS OF PLEASURE AND PAIN. 127 



le nerves distributed to the vital organs (124), and it is pro- 

 bable that by exciting the mind into action (81), the numerous 

 capillaries of the brain are stimulated, and thus by a change in 

 so large a portion of the mass of the blood, a change is pro- 

 duced in the action of the heart, in the respiration, and in all 

 the vital movements (159). 



252. The sentient actions of the pleasure of the senses are 

 movements in accordance with the natural functions of the 

 mechanical machines; those of annoyance of the senses are 

 contrary to the natural functions (80). The same apphes to 

 the sentient actions resulting from pleasing or displeasing 

 sensational conceptions, imaginations, and foreseeings (234, ii; 

 245, ii). But since a very active and inordinate discharge of a 

 function borders on the contra-natural, the sentient actions of 

 very vivid pleasurable stimuli are in some degree contra- 

 natural (199). Consequently, a state of gentle calm pleasure is 

 more favorable to the maintenance of life and to health, than 

 excess in pleasurable sensations, or than distressing painful 

 sensations. 



253. All experience establishes this doctrine. A person 

 describes a condition of health, by saying that he is well ; — of 

 sickness, by the expression he is ill. This being well and ill, 

 are sensations of what is pleasant and unpleasant (80). One 

 perfectly in health says, that not a finger aches, one out of 

 health, that nothing goes right with him ; obviously expressions 

 of what is pleasant and unpleasant, whereby we designate a 

 natural or contra -natural condition of the body. In particular, 

 it is also observed, that the change in the vital movements ex- 

 cited by moderate pleasures, are favorable to the organism, — 

 the immoderate on the painful are unfavorable. Moderate 

 laughter is beneficial, immoderate is hurtful. Agreeable exer- 

 cise of the understanding is favorable to health; and it was 

 for this reason that the ancient philosophers maintained, that 

 the study of nature favoured the attainment of old age; 

 while, on the contrary, excessive study and tiresome subtle 

 meditations led to premature decrepitude, and caused nervous 

 diseases. 



254. The general law, whereby the direct sentient actions of 

 the excitants of all the feelings are regulated, is this : — ^just as 

 a sensational or intellectual conception pleases or displeases, so 



