224 THE HUMAN BODY. 



surface of the fingers enables us to obtain, by means of it, 

 ideas of the form and relative situation of objects, of their 

 motion, their resistance, their weight, their solid or fluid con- 

 dition, of their temperature, &c. The hand grasps objects, 

 moves over their surface, follows their outline, measures their 

 distance and their extent, as far as the length of the lever 

 of which it forms the extremity will permit. By the aid of 

 this lever it raises bodies, estimates their weight, their firm- 

 ness, and their elasticity. In touching them with the ends 

 of the fingers it perceives the details of their form and their 

 relative value. We have seen of how great importance deli- 

 cacy of touch is to the artist, it is no less precious to the 

 physician, and it renders him service which he asks in vain 

 of any other sense. It is by the touch that he arrives at a 

 knowledge of the state of the circulation, the existence of 

 fluids in the tissues, and their normal or morbid consistence. 



By exercise the touch attains extreme delicacy. The 

 blind learn to read with facility from letters printed in relief, 

 and to execute certain work with tools. Saunderson, pro- 

 fessor of mathematics in the university of Cambridge, was 

 blind from his cradle, but he had attained to such exquisite 

 perfection of touch, that in a set of medals he could dis- 

 tinguish the genuine from the counterfeit pieces, though the 

 latter were so well executed as to deceive a connoisseur 

 judging by sight. He felt, by the impression of the air on 

 his face, when he was passing near a tree. It is said that 

 Jean Gonnelli, a blind sculptor, could model in clay an 

 exact copy of a statue the outline of which he had studied 

 by touch, but doubtless we must take this anecdote with 

 some allowance for exaggeration. 



However this may be, the touch has been from the earliest 

 antiquity an object of the most enthusiastic admiration to 

 naturalists. It has been considered as the most exact and 

 the most infallible of the senses, able to control their testimony 

 and rectify their errors. It has been placed in the front 

 rank, and held up as a type of which the others are only the 

 modifications. Buflbn says, "It is by the touch alone that 

 we acquire complete and accurate knowledge ; it is this sense 

 which rectifies all the other senses, which might only delude 



