10 WONDERS OF ORGANIC LIFE. 



more or less rapid, more or less complicated, the 

 direction of which is constant, and which ever 

 draws in molecules of affinity ; but at the same 

 time into which individual molecules enter, and 

 from which they are as continually thrown off, 

 insomuch as that the form of a living body is 

 more its essential, than is its constituent 

 matter. As long as this movement subsists, 

 the body in which it is in activity is living 

 — it lives ; as soon as the movement ceases for 

 good, the body dies. After death the elements 

 which compose it, rendered up to the ordinary 

 affinities of chemistry, delay not to separate 

 from each other, whence results more or less 

 the dissolution of the body which has been 

 once living. It was, then, by the vital move- 

 ment that dissolution was restrained, and that 

 the corporeal elements were for a space bound 

 in union. 



" All living bodies die after a space of time, 

 the extreme limit of which is determined for 

 every species ; and death appears to be a 

 necessary effect of life, which, by its own action 

 even, essentially alters the structure of the body 

 in which it operates, so as to render its con- 

 tinuance impossible." Yet again, therefore, the 

 question reverts — What is life, and wherefore 

 should the frame be worn out by the vital 

 actions of its own machinery? Cuvier tells 

 what the results of vitality are, as far as we 

 can appreciate them, but not what causes the 

 ever-changing combinations, the attractions 

 and repulsions which are perpetually going on 



