Developments in Plants 143 



delicate thread of semiliquid protoplasm that grows from 

 the pollen grain to the heart of the egg-bearing structure, the 

 prospective seed. 



Particularly impressive are certain details in the repro- 

 ductive processes of plants that stand between the higher 

 ferns and the seed-bearing plants — the cycads. These show 

 a combination of a primitive swimming sperm with a type 

 of egg-bearing structure approaching the seed plants. In 

 recent years the study of plant embryology has grown 

 rapidly and all the findings are in agreement with the sup- 

 position that more highly specialized types arose as modifica- 

 tions of simpler types. 



All the facts of development, then, point to this: the 

 individual diverges progressively from other individuals as 

 he grows from a primitive, simple, one-celled being. Parallel 

 facts suggest that races of one species diverge from a com- 

 mon form. The facts finally show a parallel process of 

 divergence from a common type by different species of a 

 family, by different families of an order, by different orders 

 of a class, by different classes of one of the main branches. 



It is conceivable that the inhabitants of the earth are 

 descendants of substantially identical ancestors created in 

 the first instance as adults capable of reproducing themselves 

 in their own image. It is impossible, however, to reconcile 

 this assumption with the million facts today known about 

 individual development from the e^^ unless we invent an 

 endless chain of supplementary theories to account for these 

 facts in detail. We must either assume that the creative 

 deity is a capricious being who works in an arbitrary way 

 his wonders to perform, or that there is order in the uni- 

 verse of life. 



" Hour by hour we ripe and ripe; 

 Then hour by hour we rot and rot. 

 And thereby hangs a tale." 



The other name of this tale is evolution. 



