DESCENT WITH MODIFICATION 155 



evident in the offspring. Indeed, it is well known that all char- 

 acters are not transmitted with equal intensity, but that rather, 

 in general, the intensity of transmission is somewhere in pro- 

 portion to the combined intensities of the two parents. This, of 

 course, produces results quite different from either parent taken 

 singly, and this, too, is true in general only, and not in every 

 individual instance. The visible characters of one parent, there- 

 fore, or even of both, are not an absolute index of what will 

 appear in the offspring any more than they are an absolute index 

 of their real make-up. Indeed, there is no guide to what will 

 happen in individual cases, though enough studies have been 

 made to show about what does happen in the long run ; that is, 

 how offspring in general compare with the parentage. 



The best studies that have ever been made in this field were 

 those of Galton ^ upon the stature of English people. I repro- 

 duce his table here, for it shows, as nothing else can, the rela- 

 tion between offspring in general and their parentage, though it 

 may be remarked that later and similar studies confirm the prin- 

 ciple as to other characters and in other races, as with milk 

 production in cattle (see " Principles of Breeding," p. 498^). 



In this table the heights of 928 adult offspring are classified 

 and corn pared with the stature of their parents. The heights 

 of the offspring (adult children) are listed at the top in columns 

 running from 62.2 inches and below to 73.2 inches and above, 

 with intervals of one inch. The heights of the midparents are 

 listed on the Jeft in groups also an inch apart, running from 

 64.5 inches and below to 72.5 inches and above. 



By midparental height is meant one half the combined height 

 of father and mother after increasing the mother s height by 

 one eighth (12.5 percent), because Galton found that in general 

 women are one eighth shorter than men, or rather that their 

 height must be multiplied by 1.08 to convert them into " male 

 equivalents." In this table all female statures have been so 



' An English scientist, cousin of Darwin, and author of "Natural Inherit- 

 ance," which see, together with " Principles of Breeding," pp. 479-482. 



