56 LECTURE II. 



any very important discoveries in the animal ceco- 

 nomy: nevertheless, that I may not seem entirely 

 to neglect a phenomenon which has been thought 

 worthy of attention by several eminent experi- 

 mentalists, I shall here give a short abstract of 

 Spallanzani's observations. 



Having observed that Bats would fly in the 

 most dusky chambers with precision, and not even 

 touch the walls, he found them equally exact in 

 their motions when the eyes were closely covered : 

 and at length he destroyed the eyes, and covered 

 the socket with leather ; and even in this state the 

 animal continued to fly with the same precision as 

 before; avoiding the walls, and cautiously sus- 

 pending its flight in seeking where to perch. It 

 even flies out at a door without touching the archi- 

 traves. The Abbe repeated his experiments on 

 several species of Bats; and with the same suc- 

 cess. These experiments were repeated by Vas- 

 salli at Turin, by Rossi at Pisa, Spadon at Bologna, 

 and Jurin at Geneva. Spallanzani's arguments for 

 supposing that in these instances no other sense 

 can supply the place of sight, are the following. 



" Touch cannot, in this case, supply the place 

 of sigh', because an animal covered with hair 



