Variation and Heredity 271 
to find all the individuals of a community very much alike, 
except for the fluctuating variations close around the mode? 
As a result of his studies on the stature of man, and on 
the coat color of the Basset hounds, Galton has shown that 
the inheritance from the parents can be represented by the 
fraction 4; that is one-half of the peculiarities of the individ- 
ual comes from the two parents. The four grandparents 
together count for } of the total inheritance, the great-grand- 
parents }, and so on, giving the series 4, $, 4. Pearson, taking 
certain other points into consideration, believes the following 
series more fully represents the inheritance from the ances- 
tors, .3, .15, .075, .0375, etc. He concludes that, “if Dar- 
winism be the true view of evolution, z.e. if we are to describe 
evolution by natural selection combined with heredity, then 
the law which gives us definitely and concisely the type of 
the offspring in terms of the ancestral peculiarities is at 
once the foundation stone of biology and the basis upon 
which heredity becomes an exact branch of science.” 
The preceding statements give some idea of what would 
occur in a community in which no selection was taking 
place. The results will be quite different, although the same 
general law of inheritance will hold, if selection takes place in 
each generation. If, for instance, selection takes place, the 
offspring after four generations will have .93 of the selected 
character, and without further selection will not regress, but 
breed true:to this type! “ After six generations of selection 
the offspring will, selection being suspended, breed true to 
under two per cent divergence from the previously selected 
type.” 
If, however, we do not assume that the ancestors were 
mediocre, it is found that after six generations of selection the 
offspring will breed true to the selected type within one per 
cent of its value. Thus, if selection were to act on a race 
1 In this statement the earlier ancestors are assumed to be identical with the 
general type of the population. 
