NEARLY three years ago, and before the appearance of the second volume of Weismann's Essays, in a Critique of Weismann, based entirely on statements contained in the first volume, I intimated that in my judgment he had already admitted enough to invalidate his doctrine of the non-transmissibility of acquired characters where these are of a functional nature. After showing from his own language that, according to his theory, no variation would be possible later than the Protozoan stage of development, which was a reductio ad absurdum, I proceeded to point out that, apparently from a sense of this position, he had actually admitted the possibility that external influences may affect the germ. One of the passages embodying such an admission is the following:
"I believe, however, that they [hereditary variations] can be referred to the various external influences to which the germ is exposed before the commencement of embryonic development. Hence we may fairly attribute to the adult organism influences which determine the phyletic development of its descendants. For the germ cells are contained in the organism, and the external influences which affect them are intimately connected with the state of the organism in which they lie hid. If it be well nourished, the germ cells will have abundant nutriment; and, conversely, if it be weak and sickly, the germ cells will be arrested in their growth. It is even possible that the effects of these influences may be more specialized; that is to say, they may act only upon certain parts of the germ cells."
In the same essay, speaking of the influence of climate, he also uses language that has a decidedly Lamarckian sound:
"It is difficult to say whether the changed climate may not have first changed the germ, and if this were the case the accumulation of effects through the action of heredity would present no difficulty."
Upon this, my comment was:
"I can not see why this is not conceding the whole issue. Of
- Essays upon Heredity and Kindred Biological Problems. By Dr. August Weismann. Authorized Translation. Oxford: At the Clarendon Press. Vol. i, 1889; vol. ii, 1892.
- Neo Darwinism and Neo-Lamarckism. Annual Address of the President of the Biological Society of Washington, delivered January 24, 1891. Proceedings, vol. vi, Washington, 1891, pp. 45-50.
- Essays, vol. i, pp. 103-104.
- Ibid., p. 98.