128 Evolution of Vegetal Life. 



of them were developed long ago, and when vegetation gen- 

 erally was of a simpler character. Take for instance the 

 sequoias, once numerous, of which there are now but two 

 living species, both on the Pacific slope, and of which giant 

 trees it used to be said that it required two men and a boy 

 to see to the top of one of them. Nor do I mean that 

 none of our present forms are simple and primary. I have 

 already shown you that the case is quite different. But, as 

 we shall see, there is not only no incongruity in this ; on 

 the contrary, it is in strict accordance with the theory which 

 I am attempting to illustrate. 



The theory of Evolution, as portrayed by Spencer, de- 

 scribes a progress from the homogeneous to the heteroge- 

 neous ; from the all-alike, to the greatty varied. This does 

 not necessarily imply advance in one direction. The con- 

 tribution of Darwin to this theory was the proposition of a 

 condition, of an active agent, and of the method of its ope- 

 ration ; the struggle for existence, natural selection, and the 

 survival of the fittest : of the fittest, mark you, to comply 

 with the conditions existing, — not fittest in the sense of 

 best, which is the interpretation usually put upon the term 

 by those who have not made the matter a study. We have 

 here however a good illustration of the saying that there is 

 always room at the top. The greater the variety, the more 

 certain it is that with complexity of form will come advance 

 on certain lines, because, upward and outward, the possibil- 

 ities are infinite. 



Darwin claimed, modestly but firmly, that the one named 

 by him was the principal, though not necessarily the only 

 cause of the development of all existing animal and veg- 

 etable life from simple primary forms. If you have not 

 thought carefully of the matter, perhaps you have not real- 

 ized that there is any such thing as a struggle for existence 

 in organic life, although those of you who have tackled the 

 world single-handed may perhaps be inclined to make an 

 exception in your own case. Let us see : a few suggestions, 

 only, will suffice. 



Experiment has shown that the air contains germs in 

 great variety, in numbers inconceivable. So also the soil. 

 Darwin took three table-spoonfuls of mud, from three dif- 

 ferent points beneath water on the edge of a little pond, and, 

 placing it under cover in his study, kept it there for six 

 months, pulling up and counting each plant as it grew. 



