36 Causes and Course of Organic Evolution 



evidence we suggest that in the mid-archsean epoch such regional 

 conditions must have been very frequent, and that a large 

 part of the then dry-land formed an extensive *' Yellowstone" 

 picture. 



This picture suggests a world-wide natural biochemical 

 laboratory, in which synthetic and analytic activity unceas- 

 ingly went on for at least 25 to 30 millions of years probably. 

 And with what result.^ This leads us to the fourth requirement 

 already stated, the gradual formation and establishment, 

 between distinct yet intermixed and cooperating chemical 

 bodies, of a molecular equilibrium. 



Here, it must be acknowledged, our experimental data are 

 sadly deficient, but fresh and valuable contributions are daily 

 being made that help not a little. If we compare the actions 

 and reactions of the most complex inorganic crystalloids and 

 colloids yet studied with the behavior of living self -perpetuating 

 substance, the foUoTving features impress one: 



1st. The former bodies are largely uniform, simple, and 

 direct in chemical reaction; the latter are varied, complex, 

 and indirect, or we might rather say complicated and over- 

 lapping in chemical reactions. 



2nd. The former show their energizing activity by inte- 

 grating merely molecules that resemble and add to their own 

 substance; the latter not only effect this, they are able to 

 synthesize or to analyze bodies diverse from themselves. 



3rd. The former only show the colloid phenomena of rever- 

 sible or irreversible molecular action to a limited degree; the 

 latter exhibit this in practically indefinite manner, and are 

 self-regulatory in securing discharge of superfluous products 

 by the respiratory process. 



4th. The former at any one moment show only catalytic 

 or analytic activity; the latter may simultaneously show both 

 in action. 



It would be impossible here to take up these differences in 

 detail. In some cases, as will be pointed out below, the differ- 

 ences are not invariable or in all cases fundamental. For 

 information along these lines one can consult the valuable 



