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Updated: May 24, 2025
Yet it is not at all so, and this fact seems to amount almost to an experimental demonstration that the hypothesis of pangenesis is an insufficient explanation of individual evolution. Two exceedingly good criticisms of Mr. Darwin's hypothesis have appeared. One of these is by Mr. G. H. Lewes, the other by Professor Delpino of Florence.
Upon the facts of these variations, and without accounting for them, he built his own theory of evolution. He realized his weakness, and acknowledged it in his book. He probably did not anticipate how insistently later biologists would demand an explanation that would account for this variation. In his later work, responding to this criticism, Darwin originated a theory which he called Pangenesis.
At the outset Goette indicates the distinction between Darwinism and the doctrine of Descent, and then points out that the distinguishing features of the former consist not so much in the three facts of Heredity, Variation, and Over-production, but rather in Selection, Survival of the Fittest, and also in that mystical theory of heredity the doctrine of Pangenesis which is peculiarly Darwinian.
We also meet numerous mechanical explanations of bodily structures, comparisons between anatomical conditions encountered in related animals, experiments on living creatures, systematic incubation of hen's eggs for the study of their development, parallels drawn between the development of plants and of human and animal embryos, theories of generation, among which is that which was afterwards called 'pangenesis' discussion of the survival of the stronger over the weaker almost our survival of the fittest and a theory of inheritance of acquired characters.
And there is the continuity theory which teaches that in some way or another the characteristics of the parents and other ancestors are physical parts of the germ. An attempt to explain this was made by Darwin in his theory of Pangenesis. Others have essayed what Yves Delage calls "micromeristic" interpretations.
You admit that variations in fertility and sterility occur, and I think you will also admit that if I demonstrate that a considerable amount of sterility would be advantageous to a variety, that is sufficient proof that the slightest variation in that direction would be useful also, and would go on accumulating. Sir C. Lyell spoke to me as if he greatly admired pangenesis.
As to formations without the requisite gemmules. Mr. Lewes and Professor Delpino. Difficulty as to developmental force of gemmules. As to their spontaneous fission. Pangenesis and Vitalism. Paradoxical reality. Pangenesis scarcely superior to anterior hypotheses. Buffon. Owen. Herbert Spencer. "Gemmules" as mysterious as "physiological units." Conclusion.
But if this is not the case, then a great part of the utility and distinction of pangenesis is destroyed, or as Mr. Lewes justly says, "If gemmules produce whole cells, we have the very power which was pronounced mysterious in larger organisms." Mr.
In the "Origin" Darwin throws out some suggestions as to the causes of variation, but he takes heredity, as it is manifested by individual organisms, for granted, as an ultimate fact; pangenesis is an attempt to account for the phenomena of heredity in the organism, on the assumption that the physiological units of which the organism is composed give off gemmules, which, in virtue of heredity, tend to reproduce the unit from which they are derived.
Darwin's provisional theory of pangenesis comes to something very like this, so far as it can be understood at all.
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