(506 APPENDIX B. 



external bodies, and it has but small discriminative power ; but 

 what discriminative power it has is greater on its face than on 

 its back, corresponding to the fact that the chest and abdomen 

 are much more frequently explored by the hands : this differ- 

 ence being probably in part inherited from inferior creatures ; for, 

 as we may see in dogs and cats, the belly is far more accessible 

 to feet and tono^ue than the back. No less obtuse than the back 

 are the middle of the back of the neck, the middle of the fore- 

 arm, and the middle of the thigh ; and these parts have but rare 

 experiences of irregular foreign bodies. The crown of the head 

 is occasionally felt by the fingers, as also the back of one hand 

 by the fingers of the other ; but neither of these surfaces, which 

 are only twice as perceptive as the back, is used with any 

 frequency for touching objects, much less for examining them. 

 The lower part of the forehead, though more perceptive than the 

 crown of the head, in correspondence with a somewhat greater 

 converse with the hands, is less than one-third as perceptive as 

 the tip of the nose ; and manifestly, both in virtue of its relative 

 prominence, in virtue of its contacts with things smelt at, and in 

 virtue of its frequent acquaintance with the handkerchief, the tip 

 of the nose has far greater tactual experience. Passing to the 

 inner surfaces of the hands, which, taken as wholes, are more 

 constantly occupied in touching than are the back, breast, thigh, 

 forearm, forehead, or back of the hand, Weber's scale shows that 

 they are much more perceptive, and that the degrees of percep- 

 tiveness of different parts correspond with their tactual activities. 

 The palms have but one-fifth the perceptiveness possessed by the 

 forefinger-ends ; the inner surfaces of the finger-joints next the 

 palms have but one-third; while the inner surfaces of the second 

 joints have but one-half. These abilities correspond with the 

 facts that whereas the inner parts of the hand are used only in 

 grasping things, the tips of the fingers come into play not only 

 when things are grasped, but when such things, as well as smaller 

 things, are felt at or manipulated. It needs but to observe the 

 relative actions of these parts in writing, in sewing, in judging 

 textures, tfec, to see that above all other parts the finger-ends, 

 and especially the forefinger-ends, have the most multiplied expe- 

 riences. If, then, it be that the extra perceptiveness acquired 

 from actual tactual activities, as in a compositor, is inheritable, 

 these gradations of tactual perceptiveness are explained. 



Doubtless some of those who remember Weber's results, have 

 had on the tip of the tongue the argument derived from the tip 

 of the tongue. This part exceeds all other parts in power of 

 tactual discrimination : doubling, in that respect, the power of 

 the forefinger-tip. It can distinguish points that are only one- 

 twenty-fourth of an inch apart. Why this unparalleled perceptive- 



