448 Field Museum of Natural History — Zoology, Vol, XI. 



the air might readily be perceived and the walls of caves or branches of 

 trees be thus avoided; but such an explanation seems hardly sufficient 

 to account for the ability of blinded Bats to avoid, without actual 

 contact, numerous silk threads stretched across a room, as claimed by 

 Lazaro Spallanzani, whose often quoted experiments are worthy of 

 repetition here. 



Dr. Godman writes:* "In 1793 Spallanzani put out the eyes of a 

 Bat, and observed that it appeared to fly with as much ease as before, 

 and without striking against objects in its way, following the curve of 

 a ceiling, and avoiding with accuracy everything against which it was 

 expected to strike. Not only were blinded Bats capable of avoiding 

 such objects as parts of a building, but they shunned, with equal 

 address, the most delicate obstacles, even silken threads, stretched 

 in such a manner as to leave just space enough for them to pass with 

 their wings expanded. When these threads were placed closer together, 

 the Bats contracted their wings, in order to pass between them without 

 touching. They also passed with the same security between branches 

 of trees placed to intercept them, and suspended themselves by the 

 wall, etc., with as much ease as if they could see distinctly." 



Dr. Joseph Schoblf of Prague repeated Spallanzani 's experiments 

 and confirmed his results. Bats were kept for a year alive in his room, 

 but instead of putting out their eyes he adopted a more humane method, 

 the desired results being obtained by covering them with adhesive 

 plaster. 



The following account of similar experiments by Mr. A. Whitaker 

 of Barnsley, England, is given by Millais:t 



"He obtained a Natterer's Bat and covered its closed eyes with 

 wax, fastening it with a little patch of rubber and solution, and then 

 released the Bat in a room in which it had not been before .... 

 this bHnded Bat at first flew in a hesitating manner, and then gaining 

 confidence went straight towards the closed door. It stopped when 

 about six inches away, and hovered slowly along the line of the top 

 and right down the side, without doubt keeping its position through 

 its sensitiveness to the slight draft which came through the tiny chink 



. . . It flew quickly, passing under chairs of which there were 

 twelve in the room, besides other furniture, and never even touched 

 anything with the tips of its wings. An attempt to catch it showed 

 that, although incapable of sight, it was well able to dodge, but it 

 constantly stopped in its flight, hovered, and scratched at the covering 



* Amer. Nat. Hist., I, 1826, p. 57. 



t Amer. Nat., V, No. 3, 1871, pp. 174-175. 



t Mamm. Great Brit. & Ir., I, 1904-6, pp. 96-97.' 



