SENSES OF THE BATS. 5 25 



or enables it to hear the lightest rustle. In tact bats hear the insects flying 

 past them at a considerable distance, and this sense of hearing guides 

 them in their course. Cruel experiments have been made to demonstrate 

 this fact, and it has been found that the bat's flight becomes wild and 

 uncertain when the ear or tragus is removed. 



Their powers of sight and taste are less developed. But it is to a 

 very exceptional delicacy of touch that must be attributed the ease with 

 which bats fly about in their dark retreats without striking against the 

 angles, rocky projections, or other objects. Spallanzani instituted experi- 

 ments which were decisive in this respect. The celebrated physiologist 

 destroyed the vision of several specimens, and on leaving them alone he 

 saw them fly around the room without betraying the slightest hesitation, 

 or without striking their heads against the furniture or the ceiling ; in a 

 word, without the deprivation of sight having changed in the slightest 

 degree their condition of existence. 



This fact induced Spallanzani to declare that bats are endowed with 

 a sixth sense, which informs them of the proximity of solid bodies. But 

 such an explanation is unnecessary. When we are aware of the prodi- 

 gious sensibility of the tactile organs in these animals, we may admit that 

 they are affected by certain movements of the air which are imperceptible 

 to us, and that bats can thus be rendered conscious of the proximity ot 

 a body by the obstruction to the eddies and currents of air displaced by 

 them in their flight. 



The hair with which the bat tribe is furnished, is of a very peculiar 

 character ; and although closely resembling the fur of a rat or mouse 

 when seen by the unaided eye, is so unique in aspect when seen under 

 a microscope, that a bat's hair can be detected almost at a glance. Each 

 hair is covered with very minute scales, which are arranged in various 

 modes around a central shaft. 



As might be expected from their structure, most of the bats walk very 

 badly, all slowly and clumsily. Its mode of progression is as follows: 

 The bat thrusts forward one of the fore-legs or " wings," and either hooks 

 the claw at its extremity over any convenient projection, or buries it in 

 the ground. By means of this hold, which it thus gains, the animal 

 draws itself forward, raises its body partly off the earth, and advances the 

 hind leg, making at the same time a kind of tumble forward. The process 

 is then repeated on the opposite side, and thus the creatui^e proceeds in 

 a strange and unearthly fashion, tumbling and staggering along as if its 



