Hereditary genius : an inquiry into its laws and consequences / by Francis Galton.

Date:
1869
Catalogue details

Licence: Public Domain Mark

Credit: Hereditary genius : an inquiry into its laws and consequences / by Francis Galton. Source: Wellcome Collection.

Provider: This material has been provided by the Royal College of Physicians of Edinburgh. The original may be consulted at the Royal College of Physicians of Edinburgh.

    387/468 (page 373)
    the average distribution of characteristics among a large multitude of offspring whose parentage was known. The problem would have to be attacked on the following principle. The average proportion of gemmules, modified by indi- vidual variation under various conditions preceding birth, clearly admits of being determined by observation ; and the deviations from that average may be determined by the same theory in the law of chances, to which I have so often referred. Again, the proportion of the other gem- mules which are transmitted in an unmodified form, would be similarly treated ; for the children would, on the average, inherit the gemmules in the same proportions that they existed in their parents ; but in each child there would be a deviation from that average. The table in page 34 is identical with the special case in which only two forms of gemmules had to be considered, and in which they existed in equal numbers in both parents. If the theory of Pangenesis be true, not only might the average qualities of the descendants of groups A and B, A and C, A and D, and every other combination be pre- dicted, but also the numbers of them who deviate in various proportions from those averages. Thus, the issue of F and A ought to result in so and so, for an average, and in such and such numbers, per million, of A, B, C, D, E, F, G, &c, classes. The latent gemmules equally admit of being^de- termined from the patent characteristics of many previous generations, and the tendency to reversion into any ancient form ought also to admit of being calculated. In short, the theory of Pangenesis brings all the influences that bear on heredity into a form, that is appropriate for the grasp of mathematical analysis. I will conclude by saying a few words upon what is to be understood by the phrase individuality. The artificial breeding of fish has been the subject of so many books,