130 THE WONDERS OF INSTINCT 



dribbling its thread as it goes. The rail is simply 

 doubled and has no branches anywhere, for my brush 

 has destroyed them all. What will the caterpillars do 

 on this deceptive, closed path? Will they walk endlessly 

 round and round until their strength finally gives out 

 entirely ? 



The old schoolmen were fond of quoting Buridan's 

 Ass, that famous Donkey who, when placed between two 

 bundles of hay, starved to death because he was unable 

 to decide in favor of either by breaking the equilibrium 

 between two equal but opposite attractions. They slan- 

 dered the worthy animal. The Ass, who is no more 

 foolish than any one else, would reply to the logical snare 

 by feasting off both bundles. Will my caterpillars show 

 a little of their mother wit? Will they, after many at- 

 tempts, be able to break the equilibrium of their closed 

 circuit, which keeps them on a road without a turning? 

 Will they make up their minds to swerve to this side or 

 that, which is the only method of reaching their bundle 

 of hay, the green branch yonder, quite near, not two 

 feet off? 



I thought that they would and I was wrong. I said 

 to myself : 



" The procession will go on turning for some time, 

 for an hour, two hours, perhaps; then the caterpillars 

 will perceive their mistake. They will abandon the de- 

 ceptive road and make their descent somewhere or other." 



That they should remain up there, hard pressed by 

 hunger and the lack of cover, when nothing prevented 

 them from going away, seemed to me inconceivable im- 



