THE BIOMETRIC STUDY OF HEREDITY 43 



one-half of each inherited faculty [or character], 

 each of them contributing one-quarter of it. The 

 four grandparents contribute between them one- 

 quarter, or each of them one-sixteenth, and so on, 

 the sum of the series, i + i + i + iV + ^^c., being 

 equal to one, as it should be. It is a property of this 

 infinite series that each term is equal to the sum of 

 all those that follow." The opinion of Professor Karl 

 Pearson, in which there concurs a biologist of so 

 different a school as that to which Professor J. A. 

 Thomson belongs, is that Galton's Law expresses in 

 one simple generalisation the ultimate result of all 

 the complex factors in heredity. 



Certain comments fall to be made upon this law. 

 We have already seen that, in accordance with 

 Weismann's conception of the " continuity of the 

 germ-plasm," the line of descent is not really from 

 individual to individual, but from germ-cell to germ- 

 cell. Plainly, however, Galton's Law deals with indi- 

 viduals. But Mr. Galton has himself pointed out 

 that the independent establishment of this law by no 

 means involves the rejection of Weismann's concep- 

 tion. On the contrary, the two are compatible and 

 complementary. For though Galton's Law deals 

 ostensibly with individuals, we now know enough nf 

 the origin of the individual to see that it may always 

 be taken as fairly representative of its own gurm- 

 cells, to which, indeed, its relation is not parental but 

 fraternal; for the one primal cell may be conceived 

 as giving rise by its divisions on the one hand to the 

 individual, and on the other to his germ-cells. J^iit 

 even more signiticant is the manner in which Galton's 

 Law corresponds with the observed facts of nuclear 



