40 Life and Letters of Francis Gallon
to a more rigorous analysis, but the broad conclusion to which the present results irresistibly lead, is that the same peculiar hereditary relation that was shown to subsist between a man and each of his ancestors in respect of the quality of stature, also subsists in respect to that of
eye-colour." (pp. 415-6.)
The essential fact to be remembered here is that Galton supposes the ancestral contributions which blend in the case of the stature of the individual, will be found as alternative eye-colours in the same proportions as for stature in the total group of descendants. For example, if an ancestor contributes 1/pth of his stature deviation to his descendant in the final generation, he will contribute his eye-colour to 1/pth of his descendants in the same generation.
It would be of great interest to rework Galton's proportions with the actual correlations found from his data, and with the corresponding and consistent multiple regression coefficients, and ascertain whether accordance was not sensibly improved. His parental correlation 1 is too small for his data, and his regression coefficients want considerable modification.
E. Law of Ancestral Heredity applied to Basset Hounds. Galton having applied his Law of Ancestral Heredity to Eye-Colour in Man sought for additional material to illustrate it. He found this eleven years later in Sir Everett Millais' large pedigree stock of Basset Hounds. This material reached him at the very time he was himself planning an extensive experiment with fast breeding small mammals*. One can but regret that that experiment was never undertaken. The Bassets are dwarf bloodhounds, and there are only two varieties of colour, they are either white with blotches from red to yellow technically termed "lemon and white," or they have in addition to this "lemon and white" black markings; in_ which case they are termed "tricolour." Galton had thus only two types to deal with, which he terms "tricolour" (T) and "non-tricolour' (N). A full report of his statistical reduction of Millais' data is given in a paper read before the Royal Society, June-3, 1897t.
Galton's material was contained in The Basset Hound Club Rules and Studbook, compiled by Everett Millais, 1874-1896, but with this valuable addition, that Sir Everett Millais had added the registered colours of nearly 1000 of the hounds (this copy is now in the Galton Laboratory). In this record are 817 hounds, the colour of whose parents are given, and 567 hounds in which the colours of the two parents and the four grandparents are known, and lastly in 188 cases in addition the colour of all the eight great grandparents.
Galton starts with the same idea as in the paper last dealt with, namely that each parent contributes 1, each grandparent iIV and so on, of the heritage taken as a whole to be unity. Here as in the case of eye--colour, the heritage is
* An extensive series on moth-breeding had been undertaken but had unfortunately failed to give any satisfactory results, partly owing to the diminishing fertility of successive broods, and partly to the disturbing effects of food differences and change of environment in differentyears.
t See Roy. Soc. Proc. Vol. LXI, pp. 401-413. An abstract appeared in Nature, July 8, 1897, Vol. LV, p. 235.