Mendelian heredity in man / by C.C. Hurst.

  • Hurst, C. C. (Charles Chamberlain), 1870-1947.
Date:
[1912]
Catalogue details

Licence: In copyright

Credit: Mendelian heredity in man / by C.C. Hurst. Source: Wellcome Collection.

    2/28 (page 2)
    Mudge (19), Drinkwater (9), Goddard (11), Salaman (23), and Jordan (16), provide good illustrations of the value of this method of work. During the past ten years the writer has adopted the some¬ what different method of making personal observations on the individual characters of the parents and children living in and about the village of Burbage, Leicestershire. (This district consists of an industrial village with outlying hamlets, altogether comprising a population of about 3,000 persons.) In all Men- delian researches, whether in plants, animals or Man, the advan¬ tages of personal observation seem far to outweigh the disadvantages of small numbers in a limited area. In view of the various characters touched upon in this paper, it is, of course, mpossible to attempt to deal with any single character exhaustively, consequently the paper can only be regarded as an introductory sketch. Further details may be found in the literature cited and in the forthcoming Reports of the Burbage Experiment Station. Eye-Colour. Human eye-colour depends mainly on the colour of the iris, which is largely determined by the presence or absence of two distinct layers of pigment. In the true blue eye only one of these pigmentary layers is visibly present, the posterior purple pigment of the choroid, which, being reflected through the fibrous structure of the iris produces the blue colour. In the absence or partial absence of this pigment the eye appears to be “ pink ” as in albinos. In the ordinary brown eye two layers of pigment are present, for in addition to the posterior purple layer there is also an anterior brown layer, in front of the iris. In order to distinguish eyes with two layers from eyes with one layer of visible pigment, the writer (14) in 1907 called the one Duplex and the other Simplex, and further found that these two types of eyes in their genetics follow the ordinary Mendelian rules, Duplex being dominant and Simplex recessive. Or apply¬ ing the presence and absence method—presence of the brown front layer is dominant to its absence. Simplex eyes may be any shade of blue or grey according to