GREAT STEPS IN ORGANIC EVOLUTION 399 



coagulability of the blood, the rapidity of recovery from 

 fatigue, and so forth. In other words, the organism is subtly 

 correlated not only for the everyday life of the peaceful 

 citizen, but for emergencies when it becomes necessary to 

 return to the ways of our ancestors. 



Besides the progressive organisation of structure and the 

 increasing intricacy and correlation there is a complexifying 

 of the inter-relations of organisms. There is a long gamut 

 from having an ocean to swim in and a homestead. The 

 inter-relations of earthworms are not few, but the threads 

 make much more intricate knots in the economy of birds. 

 Many of the simpler animals are related to their environment 

 whether for food, oxygen, or anything else in a very 

 generalised way ; but evolution has meant an increasing spe- 

 cialisation in the business of exploiting. 



We must not forget that alongside of the organic evolution 

 there proceeded an inorganic genesis, changes in which must 

 have meant much to life. In his charming Breath of Life, 

 John Burroughs has stated the idea picturesquely : " Does 

 not man imply a cooler planet and a greater depth and 

 refinement of soil than a dinosaur ? Only after a certain 

 house-cleaning and purification of the elements do higher 

 forms appear; the vast accumulation of Silurian limestone 

 must have hastened the age of fishes. The age of reptiles 

 waited for the clearing of the air of the burden of carbon 

 dioxide. The age of mammals awaited the deepening and 

 enrichment of the soil and the stability of the earth's crust 

 who knows upon what physical conditions of the earth's 

 elements the brain of man was dependent ? ' 



Prof. H. F. Osborn has done good service in reminding 

 evolutionists that their problem concerns four inter-acting 

 complexes of energy: the inorganic environment, the body 



