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attempt to revise the historical fiction on Pasteur's still fundamental contribution through an analysis of Pasteur's unpublished manuscripts (Cahiers de laboratoire).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. (shrink)

The facts relating to the discovery of fowl cholera vaccine did not develop along the lines described by a long tradition of scientific commentators. This results very clearly from a close analysis of Pasteur's unpublished handwritten notes. The aim of the present paper is to show that: 1) the role of chance in this discovery has no importance whatsoever; 2) in the fall of 1879 Pasteur made no crucial experiment; 3) the function of "genius" in Pasteur's discovery is to be (...) considered less important than one might think, as appears on reading the 'Cahier de laboratoire'; 4) Emile Roux played a major role in this discovery; 5) in the summer of 1880 Pasteur had no clear idea about the vaccine or about the virus attenuation method of fowl cholera. (shrink)