388 SENSATION IN GENERAL. 



monly refer our various sensations to the parts at which the 

 impressions are made, as, for instance, when we say that we 

 have a pain in the hand, or an ache in the leg, we really 

 use incorrect language ; for, though we may refer our sensa- 

 tions to the points where the impression was made on the 

 nerve, they are really felt in the brain. This is evident from 

 two facts ; first, that if the nervous communication of the 

 part with the brain be interrupted, no impressions, however 

 violent, can make themselves felt; and, second, that if the 

 trunk of the nerve be irritated or pinched anywhere in its 

 course, the pain which is felt is referred, not to the point 

 injured, but to the surface to which these nerves are distri- 

 buted. Hence the well-known fact that, for some time after 

 the amputation of a limb, the patient feels pains which he 

 refers to the fingers or toes that have been removed ; this con- 

 tinues until the irritation of the cut extremities of the nervous 

 trunks has subsided. 



487. Among the lower tribes of Animals, it would seem 

 probable that there is no other kind of sensibility than 

 that which is termed general or common, and which exists, in 

 a greater or less degree, in almost every part of the bodies of 

 the higher. It is by this that we feel those impressions, 

 made upon our bodies by the objects around us, or by actions 

 taking place within, which produce the various modifications 

 of pain, the sense of contact or resistance, the sense of varia- 

 tions of temperature, and others of a similar character. From 

 what was formerly stated ( 63) of the dependence of im- 

 pressions made on the sensory nerves upon the action of the 

 blood-vessels, it is obvious that no parts destitute of the latter 

 can receive such impressions, or (in common language) can 

 possess sensibility. Accordingly we find that the hair, nails, 

 teeth, tendons, ligaments, fibrous membranes, cartilages, and 

 bones, whose substance either contains no vessels, or but very- 

 few, are either completely incapable of receiving painful 

 impressions, or have but very dull sensibility to them. On 

 the other hand, the skin and other parts which usually receive 

 such impressions, are extremely vascular ; and it is interesting 

 to observe that some of the tissues just mentioned, when new 

 vessels form in them in consequence of diseased action, 

 become acutely sensible. It does not necessarily follow, how- 

 ever, that parts should be sensible in a degree proportional to 



