CHAP, vi.] ON CUTANEOUS SENSATIONS. 1045 



sensation of pain is not simply an exaggeration of a sensation 

 of pressure or of a sensation of temperature, but is a separate 

 sensation, developed in a different way in the skin, a sensation 

 which may override and so seem to replace the sensation of 

 pressure or temperature developed at the same time, but which 

 must not be confounded with it. And this view derives support 

 from the fact that events taking place in many other parts of 

 the body, from which we experience sensations neither of touch 

 nor of temperature, may under favourable circumstances give 

 rise to pain in varying degree. When, for instance, a tendon is 

 laid bare contact with a body will not produce tactile sensations, 

 heating or cooling will not produce temperature sensations ; one 

 cannot by means of the tendon as one can by means of the skin 

 perceive that a rough or smooth body, that a hot or cold body, 

 has been brought to act upon it. Indeed in respect to all struc- 

 tures other than the skin and nerves, to such structures namely 

 as muscles, tendons, ligaments, bones, and the viscera generally, 

 there is a large amount of experimental and clinical evidence 

 shewing that, so long as these are in a normal condition, experi- 

 mental stimulation of them does not give rise to any distinct 

 change of consciousness; a muscle or a tendon, the intestine, 

 the liver or the heart may be handled, pinched, cut or cauterized 

 without any pain or indeed any sensation at all being felt or any 

 signs given of consciousness being affected. Nevertheless when 

 the parts are in an abnormal condition even slight stimulation 

 may produce a very marked effect on consciousness. If, for 

 instance, a tendon becomes inflamed, any movement causing a 

 change in the tendon, especially one putting the tendon on the 

 stretch, will affect consciousness and give rise to a sensation. 

 But the sensation is one of pain and not of any other kind. 

 Moreover we simply 4 feel' the pain, we do not 'perceive' the 

 cause of it; because we feel the pain we infer that something 

 has caused it, but we cannot from the nature of the pain itself 

 decide whether that something is a stretching of the tendon, the 

 contact of a hard or soft body, the approach of some hot or cold 

 body, the application of some chemical substance, the passage 

 of an electric current, or intrinsic events taking place in the 

 tendon itself as the result of physiological changes. And so in 

 other instances; there is hardly a part of the body changes in 

 which may not, under certain circumstances, give rise to sensa- 

 tions of pain. We can to a variable extent, in a more or less 

 ill-defined manner, localize the sensation; we can distinguish a 

 pain in the foot from one in the leg, a pain in the thumb from 

 one in a finger ; we may occasionally fix the pain in a very small 

 limited area, though especially if the sensation be intense, the 

 pain radiates and its localization becomes obscure. And we 

 may here remark that when we thus localize a pain arising in 

 the structures of which we are speaking, we refer the pain not 



