138 Experiments on Bats deprived of Sight. 



The author then proceeds to the experiments which the 

 illuftrious Spallanzani undertook before, but in which great 

 fcope was (till left for the imagination. The author feems to 

 have found the defideratum which hia predeceflbr left for 

 thofe who might follow him in the fame path. 



He extended in an apartment feveral willow twigs three 

 feet in length, at the diftance of fix inches from each other, 

 and let loofe two bats, which pafled and repafled between 

 them, without touching them at all with their wings, and 

 which, when their flight was ended, always attached them- 

 selves to the fame cornice. The author then cut out their 

 eyes ; during which operation, the long-eared bat fuffered a 

 confiderable hemorrhage from the ocular orbits. Being let 

 loofe in that ftate, they ftill flew to the fame interftices. 

 Thefe being barred up, they made choice of others, through 

 which they pafled feveral times, always avoiding to touch 

 the twigs with their wings, and for that purpofe they pafled 

 obliquely. 



The long-eared bat fometimes ftretched out its neck, 

 and as it were made choice of that obje£t to which it 

 wifhed to attach itfclf; a cuftom which it had before it was 

 blinded. It often applied one of its hind paws to its eyej 

 collected the liquid which exuded from it, and then applied 

 it with avidity to its mouth. Thefe two bats lived a long 

 time after they were deprived of fight. Two long-eared bats, 

 the one blind, and the other having the perfect ufc of its 

 fight, were let loofe together. The blind one always fol- 

 lowed its companion, even obferving the fmallefl: finuofities 

 of its courfe. The bat which faw, pafled between the twigs 

 with lefs delicacy than the blind one. 



M. Jurine then extended a net with large mefhes, after 

 making a breach in it. The long-eared bat which faw, 

 pafled through it immediately; but the blind one flopped 

 lhort, went all over the net, and, having found the breach, 

 pafled through without touching, it, and then foon joined its 



com- 



