FACT AND THEORY 253 



Let us search always, at least for present prac- 

 tical use, for stored-up heredities; just as we 

 would seek stored-up diamonds, or gold, or coal, 

 instead of trying, by chemistry, to produce them. 



Great results are possible with time, but let us 

 seek all the short cuts we can. 



For, after all, we have so little of time ! 



With time as our limiting factor, then, we 

 shall find in plant work many things which we 

 cannot hope to accomplish. 



We shall find plants, of course, of different 

 species, and different genera — as now classified 

 — a surprising number, in spite of the old belief, 

 which will combine readily to produce fertile off- 

 spring constituting a new species or a new genus. 



We shall find plants of different species or 

 genera which combine to make a sterile offspring 

 — a mule among plants. 



And we shall find plants which can hardly be 

 combined at all — plants in which the pollen of 

 one seems to act as a definite poison on the other 

 — and plants which, through long fixed heredity, 

 seem as averse to combination as oil seems averse 

 to combining with water. 



But no man can tell until he has tried — tried 

 not once, but a few thousand times perhaps. 



"What is that?" asked a seedsman who was 

 visiting Santa Rosa. 



