Spencer’s Explanation of Use-Inheritance
Mr. Spencer’s explanation of the inheritance of the effects of use and disuse (p. 36) is that “while generating a modified consensus of functions and of structures, the activities are at the same time impressing this modified consensus on the sperm-cells and germ-cells whence future individuals are to be produced”—a proposition which reads more like metaphysics than science. Difficult to understand or believe in ordinary instances, such consensus-inheritance seems impossible in cases like that of the hive-bee. Can we suppose that the consensus of the activities of the working bee impresses itself on the sperm-cells of the drones and on the germ-cells of the carefully secluded queen? Büchner thinks so, for he says: “Although the queens and drones do not now work, yet the capacities inherited from earlier times still remain to them, especially to the former, and are kept alive and fresh by the impressions constantly made upon them during life, and they are thus in a position to transmit them to posterity.” Surely it is better to abandon a cherished theory than to be compelled to defend it by explanations which are as inconsistent as they are inadequate. New capacities are developed as well as old ones kept fresh. The massacre or expulsion of the drones would have to impress itself on the germ-cells of an onlooking queen, and the imprisonment of the queen on the sperm-cells of the drones—and in such a way, moreover, as to be afterwards developed into action in the neuters only. And use-inheritance all the while is being thoroughly overpowered by impression-inheritance—by the full transmission of that which is merely seen in others! If such a law prevails, one may feel cold because an ancestor thought of the frosty Caucasus. None of this absurdity would arise if it were clearly seen that a parent is only a trustee—that transmission and development are perfectly distinct—that parental modifications are irrelevant to those transmitted to offspring.
Footnotes
67 Essays on Heredity, p. 104. Weismann’s theory is clear, simple and convenient, but incomplete; for, unlike Darwin’s theory of pangenesis, it scarcely attempts any real explanation of the extremely complex potentialities possessed by the reproductive elements. Perhaps we might retain Darwin’s self-multiplying gemmules without supposing them to be thrown off by the cells, which will no longer be credited with two modes of multiplication. These minute germs or gemmules may have been evolved by natural selection playing upon the sample germs that achieve development; and they may exist either separately, or (preferably but perhaps not invariably) in aggregates to form Weismann’s germ-plasm.
68 Contemporary Review, Dec., 1875, p. 88.
69 Variation of Animals and Plants under Domestication, ii. 286.
70 Variation of Animals and Plants under Domestication, ii. 388, 398, 367; Life and Letters, iii. 44.
71 Contemporary Review, Dec., 1875, pp. 94, 95.