278 THE WONDERS OF INSTINCT 



Crawling up the sides, the Snails imprisoned in my 

 apparatus sometimes reach the top, which is closed with 

 a glass pane, and fix themselves to it with a speck of 

 glair. This is a mere temporary halt, in which the Mol- 

 lusc is miserly with his adhesive product, and the merest 

 shake is enough to loosen the shell and send it to the 

 bottom of the jar. 



Now it is not unusual for the Glow-worm to hoist 

 himself up there, with the help of a certain climbing- 

 organ that makes up for his weak legs. He selects his 

 quarry, makes a minute inspection of it to find an en- 

 trance-slit, nibbles at it a little, renders it insensible and, 

 without delay, proceeds to prepare the gruel which he 

 will consume for days on end. 



When he leaves the table, the shell is found to be ab- 

 solutely empty; and yet this shell, which was fixed to 

 the glass by a very faint stickiness, has not come loose, 

 has not even shifted its position in the smallest degree : 

 without any protest from the hermit gradually converted 

 into broth, it has been drained on the very spot at which 

 the first attack was delivered. These small details tell 

 us how promptly the anesthetic bite takes effect; they 

 teach us how dexterously the Glow-worm treats his Snail 

 without causing him to fall from a very slippery, vertical 

 support and without even shaking him on his slight line 

 of adhesion. 



Under these conditions of equilibrium, the operator's 

 short, clumsy legs are obviously not enough; a special 

 accessory apparatus is needed to defy the danger of slip- 

 ping and to seize the unseizable. And this apparatus the 



