SENSATION AND SENSE-ORGANS. 491 



or Organs of Special Sense / the latter are sensitive parts, 

 or Organs of Common Sensation. 



The Peripheral Reference of our Sensations, The fact 

 that we refer certain sensations to external causes is only 

 one case of a more general law, in accordance with which 

 we do not ascribe our sensations, as regards their locality, to 

 the brain, where the neurosis is accompanied by the sensa- 

 tion, but to a peripheral part. With respect to the brain, 

 other parts of the Body are external objects as much as the 

 rest of the material universe, yet we locate the majority of 

 our common sensations at the places where the sensory 

 nerves concerned are irritated, and not in the brain. Even 

 if a nerve-trunk be stimulated in the middle of its course, 

 we refer the resulting sensation to its outer endings. A blow 

 on the inside of the elbow-joint, injuring the ulnar nerve, 

 produces not only a local pain, but a sense of tingling 

 ascribed to the fingers to which the ends of the fibres go. 

 Persons with amputated limbs have feelings in their fingers 

 and toes long after they have been lost, if the nerve-trunks 

 in the stump be irritated. To explain such facts we must 

 trench on the ground of Psychology, and so they cannot be 

 fully discussed here; but they are commonly ascribed to the 

 results of experience. The events of life have taught us that 

 in the great majority of instances the sensory impulses which 

 excite a given tactile sensation, for example, have acted upon 

 the tip of a finger. The sensation goes when the finger is 

 removed, and returns when it is replaced; and the eye con- 

 firms the contact of the external object with the finger-tip 

 when we get the tactile sensation in question. We thus 

 come firmly to associate a particular region of the skin with 

 a given sensation, and whenever afterwards the nerve-fibres 

 coming from the finger are stimulated, no matter where in 

 their course, we ascribe the origin of the sensation to some 

 thing acting on the finger-tip. 



The Differences between Sensations. In both groups 

 of sensations, those derived through organs of special sense 

 and those due to organs of common sensation, we distinguish 

 kinds which are absolutely distinct for our consciousness, 

 and not comparable mentally. We can never get confused 

 between a sight, a sound, and a touch, nor between pain, 

 hunger, and nausea; nor can we compare them with one 

 another: each is sui generis. The fundamental difference 



