52 EVOLUTION OF LIFE. 



it is like the gunpowder before it detonates 

 and explodes ; the gunpowder possesses the 

 capacity to explode, the seal to impress the 

 figure, and the spring to react. These attri- 

 butes, however, which these different bodies 

 severally possess, would never be displayed, 

 unless they were placed under circumstances 

 fitted for the nature of each ; an unresisting 

 medium for the spring, a soft body like wax 

 for the seal, and a particular state of the air 

 for the gunpowder. It is the same thing with 

 respect to the living principle, and the different 

 organs which it has produced ; it not only de- 

 mands a certain state and temperature of the 

 medium in which it is placed, but particular 

 kinds of food, as well as particular conditions 

 of it, before that dormant power can become 

 poiver active, and the phenomena be produced 

 of organic action. It is in the development of 

 this power from capacity to energy, from pre^ 

 disposition to action, by which means are em- 

 ployed with a view to ends, and the final cause 

 attained for which animated beings were in- 

 tended. In proportion as the state of predispo- 

 sition departs, the state of energy accedes ; the 

 difference which subsists between both con- 

 sists in this ; in the one case, the organs, have 

 the power to act without having proper sub* 

 stances on which to operate ; in the other, the 

 power which the organs possess, is iro*edi* 



