TOUCH. 



and susceptible of great pain when irritated, and yet arc very mo- 

 derately endowed with the sense of touch. The armpits, flanks, 

 soles, and other ticklish parts have a comparatively slight power of 

 distinguishing objects by touch. " Who was ever made to laugh 

 by tickling the ends of his fingers ? and yet they are possessed 

 of a tactile accuracy far exceeding that of any other portion of 

 the skin." Mere sensibility exists in all the surfaces and solids, 

 and under disease may give sensations ; and in some internal 

 parts, as the upper and lower part of the alimentary canal, we 

 continually have sensation : but, whatever be the irritation of the 

 stomach or bowels or larynx, substances within them are felt 

 very indistinctly. 



The different parts of the skin vary exceedingly in. their 

 tactile power. Weber remarks that, if the skin of a person 

 whose eyes are shut is touched with the two points of a com- 

 pass an inch asunder, he at once perceives that he is touched 

 in two places. But, by moving the points nearer and nearer to 

 each other, the skin feels at length as if touched by simply one 

 body, and this body feels as if rather longer in the line of junction 

 of the points of the compass. There is, however, the greatest 

 difference in different parts as to their power of still feeling that 

 there are two bodies when these are approximated. The tips of 

 the fingers and of the tongue distinguish the bodies at the small- 

 est distance ; while the middle of the arm and thigh, the centre 

 of the cervical and dorsal spine, cease the soonest to distin- 

 guish at large distances. In himself Weber found the tip of the 

 tongue distinguish two bodies, as well in their horizontal as per- 

 pendicular direction, till their distance from each other was with- 

 in half a French line; the inner surface of the tips of the fingers 

 within one, &c. 



He lays it down as a law, that, the more gifted with touch are 

 any portions of the skin, the greater will the distance appear of 

 any two bodies from each other though placed at the very same 

 distance. Thus, " if the points of a compass, distant from each 

 other one or two lines, applied to the cheek, just before the ear, 

 be then moved successively to several parts of the cheek, we 

 shall find, on approaching the angle of the mouth, that the points 

 will appear to recede from each other;" or, if the ends of the 

 forefinger and thumb are held together, and their tips passed in a 



