Abstract

The anti-anthrax vaccination experiment led by Pasteur and by his closest collaborators at Pouilly-le-Fort in the spring of 1881 has long been considered by historians of science one of the most important steps in the progress of immunology against infectious diseases. The present paper is a critical attempt to revise the historical fiction on Pasteur's still fundamental contribution through an analysis of Pasteur's unpublished manuscripts (Cahiers de laboratoire). A. Loir (1938) and E. Lagrange (1954) have already hinted at the existence of the 'secret of Pouilly-le-Fort'. The secret was the use of a chemical additive (bichromate of potassium) to speed the attenuation of Bacillus anthracis. Pasteur did not mention this method for many years. He maintained, even after the Pouilly-le-Fort experiment, that the attenuation was simply due to the action of oxygen in the atmosphere. The present paper shows beyond doubt that the suspicions concerning Pasteur's communication to the Académie des Sciences were well grounded