THE SENSE OF FEELING. 2G3 



these prominences, called papillae, that the nerve-fibres enter, and It is in these 

 that we are to seek their free extremities. Attempts had accordingly been long 

 made, but in vain, to follow the nerves under the microscope to their termina- 

 tion in the papillae ; it was reserved for the above-named observers to descry, at 

 certain points of the skin, and just those indeed which are distinguished by the 

 finest sense of touch, as, for instance, the inner side of the fing-er ends, the ai3- 

 propriate apparatus in which the nerves of feeling terminate. They found that 

 in all the papillce, into which nerve-fibres enter from the deeper portion of the 

 skin, there exist small soft bulbous bodies, seemingly filled with fluid ; that to 

 each of these little bulbs one, two, or even three nerve-fibres find their way, 

 penetrate its walls at some ^oint, and having entered, each becomes divided 

 into a tuft of very delicate branches, which branches again run off each into a 

 fine point. These bulbs with their tufts of nerve-branches have received the 

 name in German, of " tastkorperchen," (touch-corpuscles,) because they un- 

 avoidably suggested to the discoverers a close connexion with the operation 

 of the nerves to which .they are attached, and for which they presumably serve 

 as sense-organs. But if we ask what takes place in the bulbs, how they oper- 

 ate as an intermediary between the outward exciting cause and the extremities 

 of the nerves, we remain at a loss for an answer. We are not yet able to in- 

 dicate even in a general way the mode of operation of these wonderful organs, 

 nor have we a full understanding of their mechanism. We have shown above 

 that for an explanation of the origin of those specific sensations of pressure and 

 temperature which only arise through an excitation of the extremities of the 

 nerves, we must suppose a peculiar apparatus for those extremities, by the in- 

 tervention of which the corresponding and appropriate modifications of the ner- 

 vous current are effected. The hope of finding this apparatus in the corpus- 

 cles just referred to vanishes, Avhen we see that these corpuscles only occur 

 in very circumscribed portions of the skin, while the sensations of touch may 

 be elicited from the whole surface. -We have seen that for an explanation of 

 perceptions relating to space, it must be supposed that each fibre possesses 

 some peculiarity in its excitation, which serves for the mind as a local sign or 

 token. The office of impressing this token on the fibres cannot possibly be 

 ascribed to the corpuscles in question, as well because the latter only occur in 

 limited places as because these local tokens, as we have seen, also accompany 

 the excitation when the fibres are excited, not at their extremities, but in their 

 intermediate passage. After amputation of a limb, the pain is referred to the 

 no longer existing part in which the ends of the excited nerves were once situ- 

 ated. Lastly, we find in places of the skin which possess these corpuscles no 

 action different from that of places which at least do not seem to possess them. 

 In short, we are forced to confess that- here are organs which we do not under- 

 stand, and the value of their discoverj!^ remains to be determined hereafter. 



Inasmuch as the operations of the sense of touch consist in the production 

 of sensations of jiressure and of temperature, each of which constitutes a peculiar 

 sphere of intelligence for the mind, we draw a distinction between a sense of pres- 

 sure and a sense of temperature. Inasmuch as each sensation of pressure and 

 temperature is attended by a perception of the place of the skin whence it is ex- 

 cited, and with this perception again a peculiar circle of intimations is associated, 

 we establish by the side of the former a sense of locality., (ortsinn,) though it 

 must always be recollected that the perception of place is not a sensation like 

 those of pressure and of temperature, but only a mediate idea connecting itself 

 with those sensations, from which indeed it is acquired. 



We first turn our attention to the sense of pressure. The proximate cause 

 of a sensation of pressure is either a pressure by which the portions of skin 

 between the nerve-ends and the object exerting the pressure are more or less 

 compressed, or a negative pressure or traction by which a stretching of the skiu 



