Publisher Information: Paris: 1868.
Pasteur at his Most Argumentative; a Very Unusual Letter
Pasteur, Louis (1822-95). Autograph letter signed, in French, to Eugène de Masquard (1819-1906). 1 page plus integral address leaf. Paris, 6 October 1868. 212 x 136 mm. Tiny tears and lacunae along folds, fore-edge of first leaf a bit frayed, light spotting but very good.
To agriculturalist and winemaker Eugène de Masquard, one of Pasteur’s most vehement opponents on the question of silkworm disease, which Pasteur had been investigating on behalf of the French government since 1865. The letter remained until recently in the Masquard family and thus has not appeared on the market before now. The text of the letter was published in Vol. IV, p. 577 of the Oeuvres de Pasteur (1926), but a comparison of the printed text to the original reveals a few small differences, including the date (given erroneously as October 3 in printed version), and the substitution of “par erreur” for the original’s “faussement” and “exagérées” for “fantaisistes.” The original letter also displays three lines heavily crossed out by Pasteur, indicative of his irritated state of mind at the time of writing.
In the 1860s the French silk industry was in serious trouble: once responsible for ten percent of the world’s production, it had become increasingly devastated by a mysterious silkworm blight that caused the industry’s output to fall by a factor of six in the years between 1845 and 1865. Though many experts, including Masquard, were attempting to solve the problem, their efforts had so far failed to uncover either the cause or the remedy for silkworm disease. It remained for Pasteur, the expert on microbes, to discover the true nature of the silkworm crisis. By 1867 Pasteur was able to show that the silkworm disease known as pébrine was caused by a parasite and the disease known as flacherie, which authorities had thought to be a manifestation of pébrine, was in reality an independent disease with its own character and etiology.
In August 1868 Pasteur presented a report to the Ministry of Agriculture containing his findings and recommending methods for combatting silkworm disease, including destroying all infected eggs and imposing stricter controls over the environmental conditions in silkworm hatcheries. The report met with some harsh criticism, including from Masquard, who in October 1868 published a derogatory article on the report in the trade newspaper Moniteur des Soies. Angered by this, Pasteur wrote Masquard this uncharacteristically testy reply (our translation):
"Sir: You recently wrote to the Director of the Moniteur des Soies, in Lyon, 'that you have always greatly admired the motto: Do what you must, come what may, and that you attempt to put it into practice as often as possible.' . . .
"Unfortunately, sir, everyone knows that it is easier to publish mottos than to follow their precepts. You have just given a new and curious proof of this well-known truth by sending to the Moniteur des Soies an extract from a Paris scientific journal concerning the report I sent recently to the Minister of Agriculture, an extract that falsely attributes to the report the most fantastical conclusions. Isn’t it your first duty to ask about the accuracy of these assertions prior to having them republished? Shouldn’t the most ordinary proprieties have made you more careful?"
Debré, Louis Pasteur, ch. 8.Book Id: 43770