LUTHER BURBANK 



mystery. It shows us that the germ-cell may be 

 indefinitely complex ; but it does not explain to us 

 how its aggregated particles which themselves 

 are all grouped within the compass of a single 

 microscopic cell can definitely determine the size 

 and form and color and peculiarities of the future 

 organism into which that cell may grow. 



In a word, the ultimate mystery of the trans- 

 mission of traits through heredity, which is in- 

 volved in the mystery of every higher organism, 

 is an unsolved enigma which challenges the pro- 

 founder insight of the future investigator. Here 

 we must be content to take the facts of heredity 

 for granted, and to point out the modus operandi 

 of inheritance without attempting to fathom its 

 precise meanings. 



In a word, the mystery of heredity is linked 

 with the mystery of life itself, and the two mys- 

 teries await a common solution. 



THE FACTS OF HEEEDITY 



The facts of heredity, considered in detail, 

 seem enormously intricate, yet they may be re- 

 duced to a few comparatively simple general 

 classes. Indeed, the broad fundamental fact that 

 each organism tends to reproduce its qualities in 

 its offspring may be said to be the one all-com- 

 passing fact that includes every minor detail of 

 hereditary transmission. 



The full meaning of this great central fact of 

 heredity was perhaps most comprehensively in- 



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