on the Sight of Bats. 135 



night birds. . He let loofe feveral birds in a -chamber per- 

 fectly dark, and perceived that the bats flew about in it 

 without any impediment, and neither rufhed againft any 

 thing in the apartment, nor touched the walls with their 

 wings. He at firft imagined that they were conducted 

 by fome glimpfe of light which he did not perceive, and on 

 that account he blindfolded them with a fmall and very 

 clofe hood. They then ceafed to fly; but he obferved at 

 the fame time, that this did not proceed from any depriva- 

 tion of light, but rather from the conftraint thence occa- 

 sioned, efpecially when a hood of a very light texture was 

 attended with the fame effect. 



He then conceived the idea of pafting up the eyes of the 

 bats with a few drops of fize or gum ; but they ftill flew 

 about in the fame manner as if their eyes had been open. 

 As this however was not fufficient, he patted up the eyes of 

 thefe animals with round bits of leather, and this even did 

 not impede them in their flight. 



That he might at length be certain of his object, he 

 blinded them entirely, either by burning the cornea with a 

 red hot wire, or by pulling out the pupil with a pair of fmall 

 pincers, and fcooping out the eye entirely. Not contented 

 even with this precaution, he covered the wounds with 

 pieces of leather, that the light might have no influence 

 whatever on the remains of the organs which had been de- 

 ftroyed. The animals feemed to fuffer very much by this 

 cruel operation ; but when they were compelled to ufe their 

 wings, either by day or by night, and even in an apartment 

 totally dark, they flew perfectly well, and with great caution, 

 towards the walls, in order to fufpend themfelves when they 

 wiflied to reft. They avoided every impediment great or 

 fmall, and flew from one apartment to another, backwards 

 and forwards, through the door by which they were con- 

 nected, without touching the frame with their wings. In a 

 word, they fhewed themfelves as bold and lively in their 



K 4 flight 



