Editing Louis Pasteur (section)

==== Initial errors ====
Arriving in Alès, Pasteur familiarized himself with pébrine and also<ref>"He had known it [= flacherie] for a long time, since his first stay in the South in 1865, where one of the two farms that had served as a starting point departure to his deductions was affected by this disease, at the same time as that of the corpuscles." Émile Duclaux, ''Pasteur, Histoire d'un esprit'', pp. 218–219, available on [https://gallica.bnf.fr/ark:/12148/bpt6k764468/f223.table Gallica] {{Webarchive|url=https://web.archive.org/web/20220126152716/https://gallica.bnf.fr/ark:/12148/bpt6k764468/f223.table |date=26 January 2022 }}.</ref> with another disease of the silkworm, known earlier<ref>"This denomination of ''white-dead'', used by the Abbé de Sauvages and several other writers, is inaccurate; this is why I thought it necessary to add that of ''dead-flats'', vulgarly used in several departments, and which designates very well the state of softness and flaccidity in which the worms dead of this disease are found. " Pierre Hubert Nysten, ''Research on the diseases of silkworms'', Paris, 1808, p. 5, available on [https://books.google.com/books?id=1tRIAAAAIAAJ&pg=PA12 Google Books].</ref> than pebrine: [[flacherie]] or dead-flat disease. Contrary, for example, to [[Jean Louis Armand de Quatrefages de Bréau|Quatrefages]], who coined the new word ''pébrine'',<ref>See account of Quatrefages reproduced in L. Pasteur, ''Études sur la maladie des vers à soie'', Paris, 1870, Complete Works of Pasteur, t. 4, p. 27, [https://gallica.bnf.fr/ark:/12148/bpt6k73599/f40.table online] {{Webarchive|url=https://web.archive.org/web/20220126152711/https://gallica.bnf.fr/ark:/12148/bpt6k73599/f40.table |date=26 January 2022 }}.</ref> Pasteur made the mistake of believing that the two diseases were the same and even that most of the diseases of silkworms known up to that time were identical with each other and with pébrine.<ref>"But the cases of association were so frequent, precisely because the disease of the corpuscles was so widespread, that Pasteur had thought that the two conditions were linked to each other and should disappear together. " (Émile Duclaux, ''Pasteur, Histoire d'un esprit'', pp. 218–219, [https://gallica.bnf.fr/ark:/12148/bpt6k764468/f223.table online] {{Webarchive|url=https://web.archive.org/web/20220126152716/https://gallica.bnf.fr/ark:/12148/bpt6k764468/f223.table |date=26 January 2022 }}.) Pasteur expressed this opinion, in particular in " Nouvelles études sur la maladie des vers à soie ", Comptes rendus de l'Académie des sciences, t. 63 (1866), pp. 126–142: "I am very much inclined to believe that there is no actual actual disease of silkworms. The disease complained of seems to me to have always existed, but to a lesser degree. (...) Furthermore, I have serious grounds for believing that most of the diseases of the silkworm which have been known for a long time are linked to the one which occupies us, muscardine and, perhaps, grasserie excepted. (p. 136). Available at [https://gallica.bnf.fr/ark:/12148/bpt6k30204/f136.table Gallica] {{Webarchive|url=https://web.archive.org/web/20220126152722/https://gallica.bnf.fr/ark:/12148/bpt6k30204/f136.table |date=26 January 2022 }}. Same thing in a letter of June 27, 1866, to Dumas: "all the other so-called ancient diseases of the silkworm, minus the ''muscardine'' and perhaps the ''grasserie'', such as the disease of '' motrs -flats'', ''petits'', ''passis'', ''arpians'', are only forms of the actual disease. " (Pasteur, ''Correspondance'', t. 2, p. 265. Quoted by Ph. Decourt, ''Les vérités indésirables'', Paris, 1989, p. 173, and by P. Pinet, ''Pasteur et la phiolosophie'', Paris, 2004, p. 158.</ref> It was in letters of 30 April and 21 May 1867 to Dumas that he first made the distinction between pébrine and flacherie.<ref>"Sur la maladie des vers à soie. Lettre de M. L. Pasteur à M. Dumas", Comptes rendus de l'Académie des sciences, meeting of 3 June 1867, t. 64, p. 1113. Available at [https://gallica.bnf.fr/ark:/12148/bpt6k3021f/f1122.table Gallica] {{Webarchive|url=https://web.archive.org/web/20220407215406/https://gallica.bnf.fr/ark:/12148/bpt6k3021f/f1122.table |date=7 April 2022 }}.</ref>

He made another mistake: he began by denying the "parasitic" (microbial) nature of pébrine, which several scholars (notably [[Antoine Béchamp]])<ref>Philippe Decourt, ''Les vérités indésirables'', Paris, 1989, pp. 165–193, accuses Pasteur of a denial of justice towards Antoine Béchamp, who studied pebrine at the same time as Pasteur and immediately affirmed the parasitic nature of the disease.</ref> considered well established. Even a note published on 27 August 1866 by [[Édouard-Gérard Balbiani|Balbiani]],<ref>Balbiani, Balbiani, " Recherches sur les corpuscules de la pébrine et sur leur mode de propagation ", Comptes rendus de l'Académie des Sciences, session of 27 August 1866, vol. 63 (1866), pp. 388–391, available at [https://gallica.bnf.fr/ark:/12148/bpt6k30204/f388.table Gallica] {{Webarchive|url=https://web.archive.org/web/20220126152715/https://gallica.bnf.fr/ark:/12148/bpt6k30204/f388.table |date=26 January 2022 }}. Balbiani begins in this manner: "Among all the contradictory opinions which have been expressed on the nature of the corpuscles of the pébrine, the most debatable, in my opinion, is that which consists in assimilating them to anatomical elements either normal, or more or less altered., or to morbid products such as pus globules, etc. This opinion was refuted more than eight years ago by Professor Lebert (...); but I believe I can also bring, against the way of seeing cited above, more decisive proofs, based on the observation of the phenomena which these corpuscles present in their evolution, phenomena which put beyond doubt their close relationship with the parasitic organisms. known under the name of ''Psorospermia''".</ref> which Pasteur at first seemed to welcome favourably<ref>"As for the opinions expressed by Mr. Balbiani on the nature of the corpuscles, although I do not share them, I will take great care to examine them, for two reasons: because they are from a skilful observer, and because I still only have preconceived views on the objects they concern, to which I do not agree more than reason. There is more: I earnestly hope that the ideas of MM. Balbiani and Leydig are true (...)". Pasteur, "Observations au sujet d'une Note de M. Balbiani relative à la maladie des vers à soie", ''Comptes rendus de l'Académie des Sciences'', meeting of 10 September 1866, vol. 63 (1866), pp. 441–443.</ref> had no effect, at least immediately.<ref>On 29 May 1867, Pasteur wrote to Dumas again: "Despite all that I would have to say about the notes of Béchamp, Estor, Balbiani and on the articles that the first two insert in the ''Messager du Midi'', I take your advice, I do not answer. If you knew how erroneous it is to say that this disease is not constitutional and only parasitic. Its essential character is precisely its constitutional character. " (Quoted by Ph. Decourt, ''Les vérités indésirables'', Paris, 1989, p. 190.)</ref> "Pasteur is mistaken. He would only change his mind in the course of 1867".<ref>P. Debré, ''Louis Pasteur'', Flammarion, 1994, p. 219. In his ''Études sur la maladie des vers à soie'' (''Studies on silkworm disease''), published in 1870 (Pasteur's Complete Works, vol. 4, available at [https://gallica.bnf.fr/ark:/12148/bpt6k73599 Gallica] {{Webarchive|url=https://web.archive.org/web/20220126152720/https://gallica.bnf.fr/ark:/12148/bpt6k73599 |date=26 January 2022 }}), Pasteur reports that he consulted Leydig on the question of the living nature of corpuscles. (One of his letters to Leydig is from December 1866.) He admits that "in substance" he adopted the opinions of Leydig and Balbiani, but he contradicts them on the question of the mode of formation of the corpuscles (pp. 135, 137 and 138). In 1884, Balbiani will examine Pasteur's theory on the development of corpuscles and will conclude as follows: "I believe that it is useless to dwell any longer on the observations of M. Pasteur, which I think I can characterize with a single word by saying that their author proves in it how little he is familiar with the researches of biology. But with this reservation, I do justice to his work, which has rendered sericulture farmers a real service by enabling them to recognize a healthy seed from a diseased seed. " (G. Balbiani, ''Leçons sus les sporozoaires'', Paris, 1884, pp. 160–163, [https://archive.org/details/leonssurlesspo00balb online.]) On Pasteur's errors in the study of silkworms and his own judgment on these errors, see Richard Moreau, "Le dernier pli cacheté de Louis Pasteur à l'Académie des sciences", La vie des sciences, ''Comptes rendus'', série générale, t. 6, 1989, n° 5, pp. 403–434, [https://www.academie-sciences.fr/archivage_site/fondations/lp_pdf/Plis_07_1869.pdf online] {{Webarchive|url=https://web.archive.org/web/20220130215818/https://www.academie-sciences.fr/archivage_site/fondations/lp_pdf/Plis_07_1869.pdf |date=30 January 2022 }}.</ref>