Paul Kammerer 1880-1926 and the case of the midwife toad.


Paul Kammerer was an Austrian biologist and expert on amphibians (herpetologist) who in September 1926 shot himself in the head 6 weeks after being accused in an article in Nature of faking one of his most important specimens. This was just before he was due to take up a senior scientific post in the new Soviet Union. He was a strong supporter of the Lamarckian view of evolution i.e. that characteristics acquired during an organism’s lifetime could be passed on to future generations. This Lamarckian view of evolution fitted in with Soviet ideology and the notion that the worker who bettered himself could pass on his improvements in himself to his children. His case was the subject of a 1971 book The case of the Midwife Toad by the author and journalist Arthur Koestler who suggested that someone other than Kammerer might have tampered with the specimen either to help Kammerer or to discredit him and he does not totally dismiss the idea of a Nazi plot to discredit Kammerer. Inheritance of acquired characteristics would be counter to the Nazi doctrine of genetic inferiority of Jews and Slavs and the genetic superiority of the Aryan races. Koestler dismisses suggestions that bias in Gregor Mendel’s experiments might be due to actions of a rogue research assistant whilst not dismissing this idea of a Nazi plot against Kammerer.

The case of the midwife toad (after Koestler, 1971)

In common pond dwelling species, male toads develop dark rough nuptial pads on their front limbs which enable them to grasp the wet slippery female during the prolonged act of mating. Midwife toads mate on land and do not have these nuptial pads and have no need for them when mating on dry land. The species gets its name because the male toad carries the fertilized eggs from its partner on its back. Kammerer claimed that when he forced midwife toads to mate in water, the males acquired nuptial pads and then passed this acquired or perhaps dormant characteristic on to future generations. The key specimen in question was a preserved male midwife toad with dark nuptial patches that Kammerer had exhibited to scientists in England in 1923. This specimen was examined in Vienna by a visiting American herpetologist, GK Noble in 1926 in the presence of an Austrian scientist and it was found that this specimen did not have roughened nuptial pads and the dark coloration was due to the presence of injected Indian ink. It was Noble’s report of these findings in Nature that triggered Kammerer’s suicide.

Koestler’s explanation of this finding by Noble was that the specimen did have genuine rough and dark nuptial pads when it was exhibited in England in 1923 and that the Indian ink was injected after its return to Vienna. Koestler suggests that the ink injection may have been an attempt to preserve the appearance of the deteriorating specimen as the natural black pigment faded due to exposure to sunlight; he even concedes that this was possibly a desperate act to maintain the specimen’s appearance by Kammerer himself although he considered this improbable. The other possible explanation was that it was done to discredit Kammerer and his theories. When I read Koestler’s book, I knew nothing of Kammerer and had only just started to research the devious activities of other fraudsters but I found it very unconvincing as a case for Kammerer’s defence.

Wider accusations and a pattern of suspicious behaviour

In an editorial in The FASEB Journal in August 2010, Gerald Weissmann makes a persuasive case that Kammerer was in fact a serial offender in manipulating specimens and that none of his key studies have ever been repeated. He quotes a report by Franz Megusar one of Kammerer’s co-workers from a 1913 publication in which he states that:

“Kammerer’s representations contain crude untruths and falsifications of the actual circumstances”

He also uses quotes from the 1960 autobiography of Alma Mahler-Werfel a one-time lover and assistant working with Kammerer who said of his experiments with salamanders:

“He wanted positive results in his research so much that he would unconsciously depart from the truth”.

She also wrote in this same source:

I kept records, very exact records. That, too, irritated Kammerer. Somewhat less accurate records with positive results would have pleased him more”.

In his experiments with spotted salamanders alluded to by Alma Mahler above, Kammerer reported that their skin patterns were heritably affected by the colour of the sand on which they were reared. These experiments were refuted by others and Kammerer admitted to his editor that he had inked in coloured spots on the photographs of salamanders used as supporting evidence supposedly to compensate for deficiencies in the photographic process.

A series of experiments with the sea squirt Ciona intestinalis is said to have been regarded by Kammerer as his most important work. These creatures have two siphon tubes which normally wave around in the sea above the animal body which is anchored to the sea bed. The animal sucks in sea water through one of these siphons and expels it through the other. These animals have the capacity to regenerate these siphon tubes if they are amputated and Kammerer claimed that when these siphons regenerated after amputation they were much longer than the originals and each time he did this they got progressively longer until they resembled “monstrous long elephant trunks”. Kammerer reported that this elongation of the siphons was then passed on to future generations i.e. inheritance of an acquired characteristic. Two contemporary scientists reported that when they cut off siphon tubes and allowed them to regenerate they were no longer than the originals.

In 1985 an eminent American biologist JR Whittaker attempted to meticulously repeat the procedures described by Kammerer which involved two sequential siphon amputations and regenerations and then a process of regeneration of the lower part of the body where the sex organs were located. Not only did Whittaker not get longer siphons after regeneration, but he also reported that the procedure in which the lower part of the body was supposed to regenerate was in fact an inevitably lethal procedure. Whittaker concluded thus:

“I was left with no remaining doubt that the Ciona results were an invention of Paul Kammerer’s high strung imagination”.

Despite having been unable to reproduce Kammerer’s experiment with Ciona and despite being convinced that the experiment could not have been conducted, Whittaker was at a loss to explain a photograph in one of Kammerer’s books of a Ciona specimen with long siphons. This was claimed to be one of the offspring of Kammerer’s regeneration experiments that had resulted in heritable siphon elongation. Whittaker later discovered that in the sea around southern Italy there is actually a variant of Ciona with naturally longer siphons than the variety found in more temperate climes including the English Channel. He implies that Kammerer collected specimens of this long siphoned variant on his travels and then presented them as long siphoned individuals produced by his regeneration experiments using the more familiar short siphoned variety.

Summing up the case against Kammerer

Just before his death, Kammerer wrote a letter that amounted to his suicide note  to the Moscow Academy of Sciences where he was due to take up a post. In this letter, Kammerer acknowledges that the key specimen of the midwife toad had almost certainly had the colour of its supposed nuptial pads artificially enhanced. However, he denies that he was the perpetrator and seems to be suggesting that someone other than himself carried out the deception for some perhaps sinister motives:

“Who besides myself had any interest in perpetrating such falsifications can only be very dimly suspected”.

Thus most of Kammerer’s key findings have been refuted by others and in the case of the sea squirt experiments, the procedures described by him are lethal to the animals. Two of those who worked with him in the laboratory suggest that he was more interested in getting the results that suited his purpose than getting the correct results and strongly imply that he was prepared to resort to improper manipulation or fabrication to get his desired results. He also seems to have admitted enhancing photographs of salamanders with dark ink spots to ensure that they supported the claims that he made. Though he denies being responsible, even Kammerer had to admit that his midwife toad specimen had been artificially enhanced. Taken together, these observations seem to make an overwhelming case for him having committed multiple acts of deception despite Koestler’s very elaborate and, in my opinion, rather contrived attempts to rehabilitate him.


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