308 SIMPLE AND COMPOUND EVOLUTION. 



and in which, being changeable less easily, they have a 

 certain persistence — a persistence which can, however, be- 

 come decided, only where further solidification stops further 

 re-distribution. 



Here we see, in the first place, what are the conditions 

 under which Evolution instead of being simple becomes 

 compound, while we see, in the second place, how the com- 

 pounding of it can be carried far only under conditions 

 more special than any hitherto contemplated; since, on the 

 one hand, a large amount of secondary re-distribution is 

 possible only where there is a great quantity of contained 

 motion, and, on the other hand, these re-distributions can 

 have permanence only where the contained motion has be- 

 come small — opposing conditions which seem to negative 

 any large amount of permanent secondary re-distribution. 



§ 103. And now we are in a position to observe how 

 these apparently contradictory conditions are reconciled; 

 and how, by the reconciliation of them, permanent second- 

 ary re-distributions immense in extent are made possible. 

 "We shall appreciate the distinctive peculiarity of the aggre- 

 gates classed as organic, in which Evolution becomes so high- 

 ly compounded ; and shall see that this peculiarity consists in 

 the combination of matter into a form embodying an enor- 

 mous amount of motion at the same time that it has a great 

 degree of concentration. 



For notwithstanding its semi-solid consistence, organic 

 matter contains molecular motion locked up in each of the 

 ways above contemplated separately. Let us note its several 

 constitutional traits. Three out of its four chief 



components are gaseous; and in their uncombined states the 

 gases united in it have so much molecular motion that they 

 are incondensible. Hence as the characters of elements, 

 though disguised, cannot be absolutely lost in combinations, 

 it is to be inferred that the protein-molecule concentrates a 

 comparatively large amount of motion in a small space. 



