200 LUTHER BURBANK 



any given generation that were not manifested in 

 the preceding generation. 



Thus any given individual has normally, as 

 a moment's reflection will show, four grand- 

 parents, eight great-grandparents, sixteen ances- 

 tors in the generation before that, then thirty- 

 two, sixty-four, one hundred and twenty-eight, 

 and so on in a geometrical ratio with each re- 

 moter generation. So the normal ancestral clan 

 of any one of us numbers more than a thousand 

 different individuals within the relatively limited 

 period of time compassed by ten generations. 



And, according to the estimate of Galton, to 

 which numberless cases of atavism give force, 

 certain traits and tendencies of each and every 

 one of these ancestors may make themselves 

 manifest in the personality of any given 

 descendant. 



Galton's studies, upon which his formula was 

 based, were chiefly made with reference to hu- 

 man beings, but we now know that the laws of 

 heredity apply with equal force to all kinds of 

 living organisms, including plants ; and whatever 

 the limitations of Galton's law as a precise for- 

 mula, there can be little question as to the general 

 truth of the principle that he invoked. 



Hence the value of that search in imagination 

 for the ancestors of our cherry in their widely 



