1872.] 



Mr. F. Galton on Blood-relationship . 



395 



I will now proceed to consider the quality of the several relationships 

 by which the above terms are connected together. 



The observed facts of Reversion enable us to prove that the latent ele- 

 ments must be greatly more varied than those that are personal or patent. 

 The arguments are as follows: — (1) there must be room for very great 

 variety, because a single strain of impure blood will reassert itself after more 

 than eight generations j (2) an individual has 256 progenitors in the eighth 

 degree, if there have been no ancestral intermarriages, while under the 

 ordinary conditions of social and neighbourly life he will certainly have 

 had a considerable, though a smaller number of them ; (3) the gradual 

 waning of the tendency to reversion as the generations increase conforms 

 to what would occur if each fresh marriage contributed a competing ele- 

 ment for the same place, thus diluting the impure strain until its relative 

 importance was reduced to an insignificant amount. It follows from these 

 arguments that for each place among the personal elements there may 

 exist, and probably often does exist, a great variety of latent elements that 

 formerly competed to fill it. 



I have spoken of the primary elements as they exist in the newly im- 

 pregnated ovum, where they are structureless but contain the materials out 

 of which structure is evolved ; the embryonic elements are segregated 

 from among them. . On what principle are they segregated ? Since for 

 each place there have been many unsuccessful but qualified competitors, 

 it must have been on some principle whose effects may be described as 

 those of " Class Representation," using that phrase in a perfectly general 

 sense as indicating a mere fact, and avoiding any hypothesis or affirmation 

 on points of detail, about most, if not all, of which we are profoundly 

 ignorant. I give as broad a meaning to the expression as a politician 

 would give to the kindred one, a " representative assembly By this he 

 means to say that the assembly consists of representatives from various 

 constituencies, which is a distinct piece of information so far as it goes, and 

 is a useful one, although it deals with no matter of detail ; it says nothing 

 about the number of electors, their qualifications, or the motives by which 

 they are influenced ; it gives no information as to the number of seats ; 

 it does not tell us how many candidates there are usually for each seat, 

 nor whether the same person is eligible for, or may represent at the 

 same time, more than one place, nor whether the result of the elections 

 at one place may or may not influence those at another (on the principle of 

 correlation). After these explanations there can, I trust, be no difficulty in 

 accepting my definition of the general character of the relation between 

 the embryonic and the structureless elements, that the former are the 

 result of election from the latter on some method of Class Representation. 



The embryonic elements are developed into the adult person. U Deve- 

 lopment" is a word whose meaning is quite as distinct in respect to form, 

 and as vague in respect to detail, as the phrase wc have just been con- 



yol. xx. 2 G 



