Correlation and Application of Statistics to Problems of Heredity 85 



means, and we might proceed at once to do this without introducing at all 

 the ideas of inheritance and regression. Galton's definition might be of 

 service if we could determine from the regression of the offspring of a single 

 pair of parents, or a few pairs, the typical centre, but this is no more feasible 

 than to determine from a few individuals the population mean ; the very- 

 backbone of Galton's conception of parental regression is that the ancestors 

 of the parents cover all the possible pairs in the community, or are on the 

 average mediocre. 



Having defined his races A and B to be those having different centres of 

 regression, which if the races are stable simply connotes different population 

 means, Galton concludes that if A and B are stable then intermediate types 

 are less stable. I think this is only a theory, not necessarily a demonstrable 

 fact. It may be that races A and B have not diverged from a common 

 ancestral race C by continuous variation, but there is nothing in Galton's 

 theory of regression to prevent A and B arising from C or even A from B 

 by continuous variation. The idea of "stability" as a source of organic 

 evolution is one that Galton was very fond of; when a race has been largely 

 selected, it topples over, so to speak, into a new form of organic equilibrium 

 with a new centre of regression. In this way Galton would account for 

 "sports" and the prepotency and permanency of certain sports, and he con- 

 siders that most breeds have arisen from sports. He then refers to various 

 kinds of sports as in peacocks, peaches, and the appearance of remarkable 

 intellectual gifts in man. Under the latter category he cites Sebastian Bach. 

 " Can anybody believe that the modern appearance in a family of a great 

 musician is other than a sport?" (p. 368). He also refers to Inaudi the 

 mental arithmetician, who started as an illiterate Piedmontese boy. In the 

 latter case, however, the Inaudi stock may well have possessed similar, if 

 less intense powers which were never called into activity, while in the former 

 case we now possess the pedigree of the Bach family, and their remarkable 

 musical power is certified for five or six generations. All variation is dis- 

 continuous when examined in small groups such as families, and the extreme 

 deviations in such small groups may be easily interpreted as sports. Newton 

 again may well have been a sport, but till we know more than we do at 

 present of his mother's ancestry, it is hardly wise to hold that he was such. 

 Nor again if some of these men are to be considered "sports," can we 

 dogmatically assert that they might, like the "japanned" or black-shouldered 

 peacocks, have produced offspring regressing to a new typical centre. 



" The phrase organic stability must not as yet be taken to connote more than it actually 

 denotes. Thus far it has been merely used to express the well-substantiated fact that a race 

 does sometimes abruptly produce individuals who have a distinctly different typical centre, in 

 the sense in which those words were defined. The inference or connotation is that no varia- 

 tion can establis+i itself unless it be of the character of a sport, that is, by a leap from one 

 position of organic stability to another, or as we may phrase it, through ' transilient ' variation. 

 If there be no such leap the variation is, so to speak, a mere bend or divergence from the 

 parent form, towards which the offspring in the next generation will tend to regress ; it may 

 therefore be called a ' divergent ' variation. Thus the unqualified word variation comprises . 

 and confuses what I maintain to be two fundamentally different processes, that of transilience 

 and that of divergence, and its use destroys the possibility of reasoning correctly in not a few 



