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Updated: May 24, 2025
Some good criticisms on this subject have been given by Messrs. Murie and Mivart, in 'Transact. The final and complete suppression of a part, already useless and much reduced in size, in which case neither compensation nor economy can come into play, is perhaps intelligible by the aid of the hypothesis of pangenesis. 'Variation of Animals and Plants under Domestication, vol. ii pp. 317 and 397.
My pages still teemed with allusions to "natural selection," and I sometimes allowed myself to hope that "Life and Habit" was going to be an adjunct to Darwinism which no one would welcome more gladly than Mr. Darwin himself. At this time I had a visit from a friend, who kindly called to answer a question of mine, relative, if I remember rightly, to "Pangenesis." He came, September 26, 1877.
Darwin, with "Pangenesis," and others, using other titles, argued in favour of a "particulate" explanation, but the number of particles which would be necessary to account for the phenomena involved, this and other difficulties, have practically put this explanation out of court.
This practice has gone on for thousands of years, and similarly also for thousands of years the rite of circumcision has been unfailingly and carefully performed. If then the hypothesis of pangenesis is well founded, that rite ought to be now absolutely or nearly superfluous from the necessarily continuous absence of certain gemmules through so many centuries and so many generations.
Must we not feel, with Darwin apparently, that the only intelligible explanation of use-inheritance is the hypothesis of Pangenesis, according to which each modified cell, or physiological unit, throws off similarly-modified gemmules or parts of itself, which ultimately reproduce the change in offspring? If we reject pangenesis, it becomes difficult to see how use-inheritance can be possible.
A large moiety of "The Variation of Animals and Plants under Domestication" , which contains the pieces justificatives of the first chapter of the "Origin," is devoted to domestic animals, and the hypothesis of "pangenesis" propounded in the second volume applies to the whole living world.
He sets forth in considerable detail a doctrine of pangenesis, not wholly unlike that of Darwin. In order to explain the phenomena of inheritance he supposes that vessels reach the seed, carrying with them samples from all parts of the body. As an outcome of this theory he is prepared to accept inheritance of acquired characters.
From a single deep impression on a parent, affecting both himself as a whole, and gravely confusing the memories of the cells to be reproduced, or his memories in respect of those cells according as one adopts Pangenesis and supposes a memory to "run" each gemmule, or as one supposes one memory to "run" the whole impregnate ovum a compromise between these two views being nevertheless perhaps possible, inasmuch as the combined memories of all the cells may possibly BE the memory which "runs" the impregnate ovum, just as we ARE ourselves the combination of all our cells, each one of which is both autonomous, and also takes its share in the central government.
The knowledge now obtained concerning the nature and action of hormones shows that such a process actually exists, and in modern theory real substances of the nature of special chemical compounds take the place of the imaginary gemmules of Darwin's theory of pangenesis or the 'constitutional units' of Spencer.
There is, however, one apparently very important phenomenon which I do not at this moment see how to connect with memory, namely, the tendency on the part of offspring to revert to an earlier impregnation. Mr. Darwin's "Provisional Theory of Pangenesis" seemed to afford a satisfactory explanation of this; but the connection with memory was not immediately apparent.
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