1420 ON CUTANEOUS AND [BOOK in. 



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 '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 sensations 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 to the structures themselves but to neighbouring 

 parts and especially to the skin ; the intense pain, for instance, of 



