THE ANIMAL KINGDOM. 159 



a soft slug, vulnerable on all sides, a cuirassed shell-snail 

 violate the asylum of the republic, a totally different result 

 ensues. As soon as the swarm begin to attack it, the 

 mollusc intrenches itself within its shell, fixes it to the 

 ground, and is then proof against all aggression. Never- 



98. Escargot, Garden-snail ^i?eKa; aspcrsa (Mull.) 



theless, as the presence of an enemy so well fenced in gives 

 them some uneasiness, and as they cannot slay it, they 

 fasten it to the spot. The workers deposit all round its 

 shell a solid frame of resinous matter (propolis) which 

 glues it firmly to the hive. The enemy must then neces- 

 sarily die in his lair, for all movement, all escape, is hence- 

 forth impossible. 



K^aumur discovered a snail cemented in this way to one 

 of his experimental hives, into which it had imprudently 

 penetrated; and I myself have seen another such prisoner 

 in the same condition. 



Do not such facts prove a certain foresight ? Could 

 blind instinct bring them about, and who could venture to 

 refer them to mere mechanical action 1 



Some insects have an idea of order and strategy. When 

 they go to the chase or to battle, as we shall see in another 

 chapter, their army advances with a care and prudence 



