710 Dynamic Theory. 



all of the vital functions. " In support of this he remarks, ' ' the pleas- 

 ures of healthy exercise and of rest after toil, the pain of fatigue, the 

 pleasures of nourishment and pure air, the pains of hunger, inanition 

 or suffocation, the pleasures of health generally, the pains of bodily in- 

 jury and disease. " While he proposes this for the general law, he is 

 obliged to admit numerous exceptions. 



But one real exception is fatal to the theory. There are many forms 

 of decay and wasting of the powers which are quite painless. Many 

 chronic ailments slowly undermine the constitution without giving any 

 warning whatever to the feelings. You may cut your finger only skin 

 deep, and suffer more pain from it than from a degeneration of the 

 heart, which is destined soon to prove fatal. If the law were true, there 

 ought, it would seem, to be a proportional correspondence between great 

 hurts and great pains, and little hurts and little pains. A rotten tooth 

 may ulcerate, poison the blood, and destroy life with little or no pain, 

 while, on the other hand, a slight and by no means fatal exposure of 

 the nerve to undue heat or cold or pressure, will produce a toothache of 

 exquisite agony. We may indulge habits of a vicious and destructive 

 kind, which are nevertheless too pleasurable to be broken off. 



Bodily pain does not necessarily depend upon the state of the viscera, 

 or the condition of the members, but upon the relationship of the brain 

 to those parts. Pleasure and pain are qualities of sensation, and all 

 sensation is in the brain. Under the influence of anesthetics, all our 

 limbs may be cut off, and our body stuck full of pins without exciting 

 pain, because the brain is not agitated by the process. If the nervous 

 connection between a leg and the brain is destroyed by a local lesion, 

 the leg may be injured without limit, but there will be no feeling of pain 

 from it. Pleasure and pain then depend upon some state or agitation 

 in the brain cells, and any stimulus which is competent to produce that 

 peculiar state of brain cells, may be said to produce pleasure or pain. 



To a person possessing musical cultivation, inharmonious sounds are 

 disagreeable or painful. Either of two sounds alonermay give pleasure, 

 while if sounded together they would give pain. We trace the pain in 

 this case not to the primary action of the vibrations themselves, but to 

 some incident of their association. The two separate agitations of brain 

 organs occurring together, leave a condensed impression in which the 

 two are blended in an inharmonious one. Evidently the element of pain 

 lies in the fact of the discord of the tones in which the brain cells are 

 agitated. Comparing these receiving organs with the receiving appa- 

 ratus of the harmonic telegraph, described in last chapter, it is easy to 

 see how two of them can be agitated at once, each one normally doing 

 its appointed work considered by itself. Thus, the C reed and the D 

 reed could be vibrated simultaneously, the one at the rate of 128 vibra- 



