Active Causes of Organic Evolution 197 



To realize vividly, however, the exact connection of it T\ath 

 each factor already noted, and its cooperative working with 

 another factor yet to be named, let us for a moment picture 

 to ourselves such often dormant bodies as a bacteroid spore, 

 a moss or fern spore, a seed of the sensitive plant, a gregarine 

 cyst, or a bird's egg. When taken from an environment that 

 favored or arrested vitality to another that started growth, 

 the first and leading result would be that in virtue of heredity 

 each would begin to unfold or grow out, and would continue 

 to do so according to details of the parent organisms, and through 

 hereditary capacity for absorbing or utilizing hereditary sub- 

 stances. But scarcely will the wall have burst than the out- 

 growing contents will be acted on by environal agents, such 

 as winds, rains, light-rays, heat, or other organisms, to mention 

 only a few, and in due time by proenvironal activity the un- 

 folding body will react to them. But some of the agents are 

 helpful, others are detrimental; and the latter, as well as the 

 former, very soon make their effects visible. Growth results 

 from the action of the helpful agencies, and then the struggle 

 becomes a successful one; arrest, reduced growth, or it may be 

 decay and at length death, result from the action of the det- 

 rimental. Then the struggle for existence becomes an unsuc- 

 cessful one. 



Since the days of the ** Evolutionary Fathers" many have 

 traced carefully and graphically the action and often the effects 

 of such struggle; while, now that we know — as with Columbus 

 and his egg — what to look for, all are becoming recorders of 

 the phenomena. 



"Selection" then is a factor that may start early in the life 

 of an organism, as when a few out of many in a batch of seed- 

 lings or in a hive of insects survive. But it often becomes 

 conspicuous in later life after the three preceding factors have 

 mainly held sway in each organism. As an active factor in 

 organic evolution then, it deserves fourth rank, for the decay 

 or death of an organism is often ensured more by the possession 

 of certain inherited qualities which under shghtly changed 

 enviroimient or defective proenvironal adjustment act pre- 



