974 CUTANEOUS SENSATIONS. 



Our sensations have as their end knowledge of the external world, 

 but knowledge of that world in relation to ourselves. Mind rarely, 

 probably never, perceives any object with absolute indifference, that is, 

 without " feeling." In other words, affective tone is the constant 

 accompaniment of sensation. Every form of common sensation is based 

 on perceptions of an altered condition of the body itself. In connection 

 with this comes the fact that all forms of common sensation possess 

 significantly pre-eminent attributes of physical pleasure or physical 

 pain. These reactions of the sensifacient organs, yielding perception of 

 altered conditions of the material " me," the mind seems to view with 

 less of philosophical indifference than it can usually behold others, e.g. 

 those of the so-called " objective " senses. Few forms of common sen- 

 sation leave the mind " unmoved." All are linked closely to emotion, 

 and, as that term implies, all operate powerfully on motor mechanisms. 

 Certain muscles — the exponents of expression — are almost uncon- 

 trollably excited. The reaction plays also upon the local musculature 

 in a manner curiously imperative. 



The facility of path of these motor reflexes colligated to pain, hints at their 

 antiquity, or at their having been formed by some neural method particularly 

 able to, as it were, make a good road. Each reaction that employs a 

 neural path seems to smoothe it by sheer act of travel. This is true even 

 of slight impulses — light traffic — and more true of heavy. Pain reactions are 

 to he regarded as very heavy traffic. Their impressions summate with peculiar 

 ease, take correspondingly long periods to subside, and, to judge by their 

 inertia, move generally masses of neural material relatively great. Such 

 impressions might wear a road with quite especial speed. Many spinal 

 reflexes imply, so to say, well-worn habits based on ancient pain reactions. 

 One is almost emboldened to figuratively imagine them as connate memories 

 of the spinal cord. The majority of them seem to be protective reactions that 

 in organisms of high neural type are accompanied by " pain." 



Pain seems the psychical adjunct of protective reflexes. A pain 

 reaction is in so far like a nauseous taste attaching to a poison. The 

 temperature at which the skin begins to evoke pain (48° C.)is that at which 

 nerve substance begins to suffer injury. 1 The sensation caused by the 

 pressure of a sharp point {e.g. needle) on the skin is felt to be painful 

 just below the pressure sufficient for the instrument to break into the 

 skin, i.e. the stimulus becomes painful just before it does injury. True, 

 that the material " me " usually affects little the flow of healthy con- 

 sciousness. Nevertheless, on the existence of that material "me" 

 depends the very existence of that consciousness. It is the material 

 " me " of which Lotze's trodden worm thinks when it contrasts its own 

 suffering self against the whole remaining universe. The directness 

 of nexus between excitation of pain on the afferent side and certain 

 especially localised movements on the efferent, is argued to be the 

 "instinctive" outcome of this, and of "protective" significance. The 

 plan of defence often lies patent in the character of the movement. 

 The tail is retiexly twitched away from the side to which the painful 

 stimulus is applied. 2 The pain reflex causes the pinched foot to be 

 withdrawn. The epigastric pain of hunger can be relieved by putting 

 food into the stomach ; the faucial pain of thirst by the swallowing of 

 fluid. Both " needs," so long as the cerebral hemispheres are in function, 



1 E. H. Weber, loc. cit. 



2 E. Pfliiger, ''Die sensorischen Functionen des Riickenmarkes," Berlin, 1853. 



