Blood transfusion in rabbits: no gemmules in the blood
An experiment in which pangenesis was tested literally: if gemmules travel through the body in the blood, then after transfusing silver-grey rabbits with large quantities of lop-eared blood one could expect foreign characters in their offspring.
The experiment was made in 1871 by the Englishman Francis Galton, Darwin's cousin. Darwin helped, put him in touch with rabbit breeders and demanded reports. The result, as Cowan gives it: 124 offspring in 21 litters, not a single 'mongrel'. Darwin replied in Nature that in the chapter on pangenesis he had 'not said one word' about the blood and that Galton's conclusion was 'a little hasty'; Galton apologised and closed his letter with 'Vive Pangenesis', but stopped looking for particles in the blood and a year later proposed his own theory of hereditary units.
The experiment did not prove that gemmules do not exist at all, but it took from them the only plausible way of moving through the body.
Why this date
High for the year. The paper 'Experiments in Pangenesis, by breeding from rabbits of a pure variety, into whose circulation blood taken from other varieties had previously been largely transfused' was read to the Royal Society on 30 March 1871 and printed in Proceedings of the Royal Society, vol. 19, pp. 393-410 (checked against the article record on the Royal Society site). The experiments ran from late 1869, hence the lower bound of the label.
Other links
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Pangenesis: gemmules from the whole body gather in the germ cells
refuted by · Confidence: high
Galton tested the only plausible route of gemmules through the body, the blood: after massive transfusions from rabbits of other breeds, 124 offspring in 21 litters came out pure-bred. He concluded that the blood carries no gemmules, and scientific opinion on pangenesis, historians say, turned quickly to scepticism thereafter.
Dispute: The dispute took place at once and in print. Darwin replied in Nature on 27 April 1871 that in the chapter on pangenesis he had 'not said one word about the blood, or about any fluid proper to any circulating system', that the hypothesis covers Protozoa and plants, which have no blood, and that Galton's conclusion was 'a little hasty'; Cowan calls this nit-picking, since Darwin had written of 'the steady circulation of fluids throughout the body' and in a year of correspondence never questioned the design of the experiment. Galton apologised on 4 May 1871 and closed his letter with 'Vive Pangenesis'. Karl Pearson in 'The Grammar of Science' (2nd ed., 1900, p. 335) objected that pangenesis is no more disproved by gemmules not found in the blood than the atomic theory by atoms not found in the air (given after the English Wikipedia article 'Pangenesis'; the page of the book was not checked). What finally removed the hypothesis from the agenda was not the rabbits but Weismann's germ plasm and the rediscovery of Mendel in 1900; here Galton's experiment is taken as the first refutation and the germ plasm as the second.
Link sources
- Ruth Schwartz Cowan, Commentary: Before Weismann and germplasm there was Galton and eugenics, International Journal of Epidemiology 45 (1), 15-20 (2016) Verified 20 Sep 2026
the results were negative; out of 124 offspring in 21 litters born by transfused rabbit does, not a single ‘mongrel’ had appeared. Galton presented a full report of his findings to the Royal Society in March, 1871.
- Yongsheng Liu, Qi Chen, 150 years of Darwin's theory of intercellular flow of hereditary information, Nature Reviews Molecular Cell Biology 19 (12), 749-750 (2018) Verified 20 Sep 2026
In a series of blood transfusion experiments, Francis Galton failed to detect fur colour changes in the offspring of silver-grey rabbits that were transfused with the blood of lop-eared rabbits; he concluded that the blood did not carry Darwin’s hypothetical gemmules.
- Charles Darwin, Pangenesis, Nature 3 (27 April 1871), 502-503 (Darwin Online, F1751) (1871)
These experiments were undertaken to test whether there was any truth in my provisional hypothesis of Pangenesis.
"Verified" means that on that day the quotation was found at the address given, word for word. No date means we have not been able to open the source yet, not that the quotation is wrong.
- Ruth Schwartz Cowan, Commentary: Before Weismann and germplasm there was Galton and eugenics, International Journal of Epidemiology 45 (1), 15-20 (2016) Verified 20 Sep 2026
Node sources
- Francis Galton, Experiments in Pangenesis, by breeding from rabbits of a pure variety, into whose circulation blood taken from other varieties had previously been largely transfused, Proceedings of the Royal Society of London 19, 393-410 (1871) Verified 25 Sep 2026
Darwin’s provisional theory of Pangenesis claims our belief on the ground that it is the only theory which explains, by a single law, the numerous phenomena allied to simple reproduction, such as reversion, growth, and repair of injuries. On the other hand, its postulates are hypothetical and large, so that few naturalists seem willing to grant them.
- Ruth Schwartz Cowan, Commentary: Before Weismann and germplasm there was Galton and eugenics, International Journal of Epidemiology 45 (1), 15-20 (2016) Verified 20 Sep 2026
Galton proposed to transfuse blood between rabbits of different breeds in order to see whether the traits of the donor rabbits (particularly coat colour) would appear in the offspring of the recipients. Darwin put Galton in touch with rabbit breeders and, for the next year, insisted on being kept apprised (by letter) of the progress of the experiments.
- Ruth Schwartz Cowan, Commentary: Before Weismann and germplasm there was Galton and eugenics, International Journal of Epidemiology 45 (1), 15-20 (2016) Verified 20 Sep 2026
the results were negative; out of 124 offspring in 21 litters born by transfused rabbit does, not a single ‘mongrel’ had appeared. Galton presented a full report of his findings to the Royal Society in March, 1871.
- Charles Darwin, Pangenesis, Nature 3 (27 April 1871), 502-503 (Darwin Online, F1751) (1871)
IN a paper, read March 30, 1871, before the Royal Society, and just published in the Proceedings, Mr. Galton gives the results of his interesting experiments on the inter-transfusion of the blood of distinct varieties of rabbits. These experiments were undertaken to test whether there was any truth in my provisional hypothesis of Pangenesis.
- Ruth Schwartz Cowan, Commentary: Before Weismann and germplasm there was Galton and eugenics, International Journal of Epidemiology 45 (1), 15-20 (2016) Verified 20 Sep 2026
Despite the failure of the rabbit experiments, Galton never gave up his conviction that some sort of hereditary particle existed: his apologetic letter to Nature ends with the words, ‘Vive Pangenesis’.
"Verified" means that on that day the quotation was found at the address given, word for word. No date means we have not been able to open the source yet, not that the quotation is wrong.