The JVisdoin of Instinct 1 7 1 



inflicted by the Sphex ; and nevertheless for 

 seventeen days I saw her continually waving 

 her antennae. As long as this sort of pendulum 

 keeps on swinging, the clock of life does not 

 stop. On the eighteenth day the creature 

 ceased its antennary movements and died. 

 The badly-wounded insect therefore lived, under 

 the same conditions, four times as long as the 

 insect that was untouched. What seemed as 

 though it should be a cause of death was 

 really a cause of life. 



However paradoxical it may seem at first 

 sight, this result is exceedingly simple. When 

 untouched, the insect exerts itself and conse- 

 quently uses up its reserves. When paralysed, 

 it has merely the feeble, internal movements 

 which are inseparable from any organism ; and 

 its substance is economized in proportion to the 

 weakness of the action displayed. In the first 

 case, the animal machine is at work and wears 

 itself out ; in the second, it is at rest and saves 

 itself. There being no nourishment now to 

 repair the waste, the moving insect spends its 

 nutritive reserves in four days and dies ; the 

 motionless insect does not spend them and lives 

 for eighteen days. Life is a continual dissolu- 

 tion, the physiologists tell us ; and the Sphex' 

 victims give us the neatest possible demon- 

 stration of the fact. 



