42 HEREDITY [ch. 



metaphor of bequests of property, he calculated that 

 of the total heritage of an individual, half on the 

 average was bequeathed by the parents, one quarter 

 by the grandparents direct to the grandchild and so 

 on, Pearson's series '5, '33, '22 etc. gives the average 

 measure of resemblance between children and an 

 ancestor of each generation, which is clearly a totally 

 different thing. From this series he has worked out 

 figures corresponding to Galton's, making the series 

 •6244, -1988, "0630, i.e. he finds that the parental 

 bequest is greater and the ancestral bequests less 

 than Galton estimated. From the results obtained 

 first by Galton and later by Pearson has been formu- 

 lated the 'Law of Ancestral Heredity,' which has 

 been stated in various forms, perhaps the most 

 general being 'the mean character of the ofispring 

 can be calculated with the more exactness, the 

 more extensive our knowledge of the corresponding 

 characters of the Ancestry ' (Yule [44]). But it should 

 be noted that there is an important diflbrence between 

 Galton's original statement of the law, and the later 

 statements of Prof. Pearson. Galton wrote that ' the 

 two parents between them contribute on the average 

 one-half of each inherited faculty, each of them 

 contributing one-quarter. The four grandparents 

 contribute between them one-quarter, or each of 

 them one-sixteenth ; and so on.' He regarded this 

 as a physiological statement of the way faculties 



