Paul Kammerer was an Austrian biologist in the early twentieth century. After initially training in music, he graduated with a degree in biology and began his career at the Vienna Institute for Experimental Biology. His work, once lauded, later placed him at the center of a scientific controversy. Kammerer’s name became linked with accusations of fraud, and the ensuing scandal transformed his legacy into a tragic story that left a lasting mark on the history of science.
Champion of Lamarckian Inheritance
Kammerer’s research focused on the theory of Lamarckian inheritance, which proposes that organisms can pass on characteristics acquired during their lifetime to their offspring. This concept contrasted with Darwinian evolution, based on random variation and natural selection. Kammerer conducted numerous studies with amphibians, aiming to provide experimental proof that the environment could directly influence heredity.
One experiment involved fire salamanders. By raising them on different colored soils, he claimed to alter their skin coloration and that these new patterns were inherited by the next generation. Another project focused on the sea squirt, Ciona intestinalis. Kammerer reported that after amputating their siphons, they regenerated to a greater length, and this acquired trait was passed down to their progeny.
The Midwife Toad Scandal
The experiment that defined Kammerer’s career involved the midwife toad, Alytes obstetricans. As a terrestrial species that mates on land, the males lack the dark nuptial pads that aquatic toads use to grip females in water. To show that an environmental change could trigger this latent trait, Kammerer raised the temperature in their enclosures, compelling the toads to breed in water.
Kammerer announced that after several generations of forced aquatic mating, the male midwife toads developed nuptial pads. This result was presented as proof of Lamarckian inheritance and brought him international attention. A preserved specimen of a male toad with these dark pads became his primary evidence, and his findings were celebrated with lectures at institutions like the University of Cambridge.
In 1926, American zoologist Gladwyn Kingsley Noble, a skeptic of the work, visited Vienna to examine Kammerer’s last specimen. Noble then published a letter in the journal Nature on August 7, 1926, claiming the black nuptial pads were not a natural development. He stated they had been artificially created by injecting India ink under the skin, implying deliberate fraud.
A Career’s Tragic End
Noble’s public accusation destroyed Kammerer’s career, as the charge of fraud cast a shadow over all his work. The accusation came just after Kammerer had accepted an offer to establish an institute at the Moscow Academy of Sciences, reflecting his international standing before the scandal.
Six weeks after Noble’s article appeared in Nature, Paul Kammerer took his own life. On September 23, 1926, he died by gunshot in a forest on the Schneeberg mountain, an act widely interpreted as an admission of guilt.
In a final letter to the Moscow Academy of Sciences, Kammerer maintained his innocence. He confirmed Noble’s finding that the specimen was injected with ink but denied any knowledge of the deception. Kammerer wrote that he concluded someone else, perhaps a lab assistant, must have tampered with his evidence, adding a layer of mystery to the affair.
Vindication Through Epigenetics?
Decades later, Arthur Koestler’s 1971 book, “The Case of the Midwife Toad,” re-examined the case. Koestler argued that Kammerer was likely innocent of fraud, suggesting the specimen might have been sabotaged by a rival or political adversary. At the University of Vienna, Nazi sympathizers were becoming hostile toward Kammerer, a known socialist.
The modern field of epigenetics adds another dimension to Kammerer’s legacy. Epigenetics studies how environmental factors alter gene activity without changing the DNA sequence. These modifications, such as DNA methylation, can switch genes on or off, and some have been found to be heritable. This field provides a plausible mechanism for the principle Kammerer championed: that the environment could induce heritable changes.
This new understanding has led some to reconsider Kammerer’s work. While the findings of the Midwife Toad experiment are still considered compromised by the ink injections, the underlying concept is no longer dismissed outright. The science of epigenetics suggests that the inheritance of acquired traits is not as impossible as was once believed, casting Kammerer’s story in a more complex light.