no ANAI-YSIS OF THE FOUR PRINCIPLES. 



ished one-eighth. In the second generation the result will be quite 

 different ; for variations 2 and 4 already constitute two-thirds of the 

 whole number of pure-breeds. 



Second Generation — Pure-breeds. 



Of variation i 250 



Of variation 2 . i , 000 



Of variation 3 ... 444 



Of variation 4 . .1,776 



3,470 

 In this generation the decrease is only 28 individuals, or about ^. 



Third Generation — Pure-breeds. 



Of variation i . . . ... 125 



Of variation 2 . i , 000 



Of variation 3 . 296 



Of variation 4 . 2, 368 



3,789 

 In this generation there is an increase of 319 individuals, or a little 

 ver 1 



Fourth Generation — 

 Of variation i 



Of variation 2 . . . 



Of variation 3 . . . 



Of variation 4 . . . . 



4,416 



In this generation there is an increase of 627, or of nearly -g-. 



Tenth Generation — Pure-breeds. 



In variation i ... 0.98 



In variation 2 • i , 000 



In variation 3 . . 16 



In variation 4 . . . 17,758 



18,775 



Var. 4, of Tenth Generation = 1,000 (1.33334)'° computed by logarithms. 



We therefore observe that in the tenth generation variation i has 

 become less than i , and variation 4 has become the predominant type. 



For the next ten generations the average positive segregation will be 

 advanced, (i) by the preponderance of variation 4, and (2) b)'^ the 

 fact that the new variety occurs in much larger masses than at the 

 beginning of the computation, and will therefore be less exposed to 

 cross-fertilization . 



Now that the mass of pure-breeds is increased more than fourfold, 

 it is reasonable to suppose that the ratio of pure-breeding advances. 



