258 PLANT PHYSIOLOGY 



and the activities, of the offspring were those of the parents. 

 There is no gap or break, there is perfect continuity. If a 

 gap were to occur, nothing could bridge it, there would be 

 nothing with which to bridge it, the species or the race 

 would be extinct. A new creation would be necessary, and 

 experience does not encourage belief in new creations. Ee- 

 production, then, prevents the formation of a gap. When 

 death comes to an organism which has already formed a 

 new individual consisting of and continuing the substance, 

 structure, and activities of the old, death effects no break, 

 there is no gap. When death comes to an organism which 

 has not yet grown beyond itself, a gap is formed, but 

 forined too soon ever to be bridged or closed. 



The chief end of reproduction is, then, the maintenance of 

 life, the continuity of the species. Another end is only less 

 important, that of increasing the number of individuals. 

 The parent stalk of wheat which has given all its living 

 substance to the two dozen or so new individuals enclosed 

 within the kernels it has produced, is contributing to in- 

 crease the number of wheat individuals living next year. As 

 we know, there will be no real increase, however, unless 

 these kernels fall into spots where no plant or only a weaker 

 one lived before. Under natural conditions, which have so 

 long remained the same that the possibilities of the situa- 

 tion are as fully exploited by the organisms living there 

 now as can be the case at the present stage in evolution, 

 there will be no vacant spots in which an increased number 

 of individuals can live. Under these conditions reproduction 

 cannot effect an increase, it can only continue the life, of the 

 species. However, when any new factor is introduced, when 

 seismic disturbance, or climatic change, or the entrance of 

 some new and powerful organism, modifies the conditions, 

 each new individual in a brood or crop has a different 

 chance from before, a better chance or a worse according to 

 the relative characters of the new individual and of the 

 changed environment. Those organisms which have young 

 ready and able to take advantage of the changed environ- 

 ment will thereby have a better chance to increase their 

 kind as well as to maintain it. As the maintenance of the 



