80 SENSIBILITY OF THE BAt's WING. 



part of the membrane which extended between the two 

 hind legs ; by which artful means he gained his point, 

 and swallowed his prey without further difficulty. 



Spallanzanij a naturalist of great eminence, disco- 

 vered that bats, when perfectly blinded, and after- 

 wards set at liberty, had the extraordinary faculty of 

 guiding themselves through the most complicated 

 windings of subterraneous passages without striking 

 against the walls ; and that they avoided, with great 

 nicety, cords^ branches of trees, and other obstacles, 

 placed, by design, in their way. He was so much at 

 a loss to conjecture how this was effected, that he at- 

 tributed it to some unknown sense bestowed upon this 

 creature for its security. But Mr. Palmer very inge- 

 niously attributes it to an extreme delicacy of feeling 

 in the wing, which presents to the air an enormous 

 surface in proportion to the size of the animal, and is 

 covered with an exquisitely fine net- work of nerves. 

 He therefore supposes that, in the action of flight, the 

 ail", when struck by this wing, so well adapted to its 

 office, impresses a sensation of heat, cold, or resistance, 

 which directs the bat to avoid any object that would 

 obstruct its flight ; just as you may have seen a blind 

 person perceive a door, or a wall, by the difference of 

 the resistance of the air, without the assistance of 

 touch.* 



* See Bingley's British Quadrupeds, p. 35. 



