A SIXTH SENSE. 241 



pursuing its flight in the dark cavernous retreats it frequents, or 

 when flying abroad in the dusky air of evening. With a zeal 

 for the advancement of knowledge which apparently rendered 

 him oblivious to the cruelty of his proceedings, that eminent 

 naturalist first deprived the I'ats he experimented upon of their 

 eyes, and then set them at liberty in a large apartment in which 

 were placed lines and rods crossing each other in every direction 

 and from which escape could only be made by apertures barely 

 large enough ta allow the animals to pass without their striking 

 against the sides. And yet we are assured the poor blinded 

 creatures threaded the maze of obstructions without once coming 

 in contact with them, and finally passed out of the apertures, 

 without even brushing the sides with their wings. It has been 

 questioned by many naturalists whether this extraordinary 

 ]K)\ver of ascertaining the proximity of solid bodies should be 

 regarded merely as an extension or refinement of the sense of 

 touch, or as a sixth and unnamed sense peculiar to the Bat tribe. 



It seems, however, that this extraordinary power of ascertain- 

 ing the proximity of solid bodies is in some measure dependent 

 on the sense of hearing, which with that of smell is also 

 developed to an unusual degree in many of the Bat tribe, the 

 organs of those senses being proportionately conspicuous. In tho 

 Long-eared Bat of this country the ears are nearly equal to 

 the body in length, and there is an inner fold of the membrane 

 of the external ears which has the appearance of a second pair 

 of those organs. The nose, again, often partakes of the same 

 singular development, being furnished with curious leaf-like 

 appendages, formed by a prolongation of the skin, which is folded 

 and doubled in various directions, so as frequently to present a 

 most grotesque appearance, as in the Horseshoe Bats. But 

 these peculiarities of structure are confined to that division of 

 the tribe which capture insects on the wing, and are wholly 

 wanting in those species which subsist on fruits and other vege- 

 table food. 



The Bats come abroad almost exclusively during twilight 

 and the darkness of night, remaining concealed by day in hollow 

 trees, caverns, and holes in rocks, the dark recesses of ruins, 

 under the eaves of houses, and other similar situations. 



There are few places, indeed, at all capable of affording the 

 Bat a safe retreat during its daily rest which are not turned tu 



