Heredity / by J.A.S. Watson.

  • James Anderson Scott Watson
Date:
[1912]
Catalogue details

Licence: Attribution-NonCommercial 4.0 International (CC BY-NC 4.0)

Credit: Heredity / by J.A.S. Watson. Source: Wellcome Collection.

    18/104 (page 16)
    16 HEREDITY from germ cell to germ cell, and that the body cells in each generation are regarded as an offshoot, and as having no function in reproduction beyond that of guarding and nourishing the germ cells. The process of the setting apart of the germ cells at the commencement of development is not an imaginary one. In several instances it has been clearly distin¬ guished under the microscope. To endeavour to make this clearer, we may imagine a potter at work. He has a mass of clay ready kneaded by his helper, and from this he cuts ofí a piece sufficient for a vase. He moulds his vase, which is dried and burnt in the kiln, and can never be turned back into the original soft, plastic clay. But meantime his helper ABC Fig. 2. has been at work increasing the size of the original lump, so that he can immediately proceed to make another vase from it. The lump of clay, ever growing, ever about the same in character, is the germ plasm. The vases, which we can suppose to be turned out on the same pattern, are the successive generations. Only to make our metaphor complete, the lump of clay would require to be placed inside the developing vase, and to grow there. Besides, of course, the whole process goes on of itself. The consequences of this theory are far-reaching. The connection between the characters of one genera¬ tion and those of the next is not direct, but indirect. The son's characteristics do not depend directly on the father's, but indirectly in the sense that both depend