Corentin Louis Kervran - Calcium Anomalies in Chicken Eggshells

Calcium Anomalies in Chicken Eggshells

Kervran initiated his fascination for science with the apparent enigma of eggshell formation. As a youth Kervran had read a reference to Louis Nicolas Vauquelin's observations on the formation of eggshell in Gustave Flaubert's "Bouvard et Pécuchet". Kervran later succeeded in finding Vauquelin's original text on the apparent anomalous increase in calcium in a chicken whose diet is limited to potassium-rich oats. How did it continue to produce eggs with calcareous shells on a calcium poor diet on a soil entirely lacking in limestone?

Contemporary biochemist believed that chickens fed on the calcium reserve of their skeletons to produce eggs. Kervran did not accept this since chickens deprived of calcium laid soft-shelled egg until they ingested the potassium-rich oats, at which point they laid calcareous hard-shelled eggs. Kervran did not consider how the potassium could contribute to other chemical based biological pathways that lead to shell hardening.

In response to Kervran ideas Nuclear scientists stated if the chickens were to turn potassium into calcium at the rate of several grams a day, the released nuclear fusion energy of the order of 8 MeV would have turned them into atom bombs. Kervran rationalized this discrepancy by believing that the transformation of potassium into calcium (transmutation) happened at low energy. This became Kervran's thesis on which he staked his career. He developed a different model of low-energy transmutation that he called "frittage".

The scientists who collaborated with Kervran on many of his specialized experiments gradually referred to the thesis of transmutation at low energy as the "Kervran effect".