96 GEOLOGICAL BIOLOGY. 



Evolution was already progressing as far back as we can find 

 fossils, and appears to be going on still. Organic develop- 

 ment repeats itself over and over and over again, producing 

 cycles of changes, each one of which constitutes the life-history 

 of an individual organism, each cycle with almost impercepti- 

 ble variations, the same from generation to generation in each 

 series; but organic evolution, although it is by slow pro- 

 cesses, constitutes a continuous series ; there are no repetitions 

 in the series. Looked at from the point of view of our knowl- 

 edge, the series had a beginning, and the evolution has been 

 continuous since the beginning, and is not stopped to-day. 



But the evolution has been an evolution entirely of form 

 and function, not of substance. The same substance, that is, 

 matter, has been used over and over again : the materials 

 have preserved the same chemical and physical properties, 

 have been temporarily built up to form new combinations, 

 have taken organic form, have performed their function, have 

 died and gone back to their simple condition again. As far 

 as can be ascertained, no change has taken place in the nature 

 of matter; what it is to-day matter has been as far back in 

 time as science can penetrate. 



Evolution an Organic Process, and not Applicable to Inorganic 

 Things. — Thus we reach the undeniable conclusion that or- 

 ganisms, which fossils represent, are something unique and 

 distinct from other things in nature. The physical constitu- 

 tion of matter presents no evolution. What it is, it was back 

 into the mists of eternity. Chemical properties of matter 

 offer no law of evolution. We interpret the chemistry of the 

 sun, or the most distant stars, by the same tests we use in 

 our working laboratories upon the things about us. The 

 crystalline properties of minerals offer no evolution ; the 

 angles of a quartz crystal and the system of its crystallization 

 in the Archaean granite are precisely those exhibited by quartz 

 crystallizing at the present day. 



Fossils furnish the Direct Evidence of Evolution. — Fossils first 

 exhibit to us true evolution; and this evolution, which we 

 recognize as an orderly sequence or progress of events, be- 

 comes the fundamental characteristic of organisms, and is an 

 essential peculiarity of organic activity. Fossils not only 



