Paris: Mallet-Bachelier, 1858; 1860.
First printings, in the very rare offprint form (first paper inscribed by Pasteur), of these two landmark papers, “often considered the beginning of bacteriology as a modern science, [which constitute] the first demonstration of the connection between a specific fermentation and the activity of a specific microorganism” (Garrison & Morton); “A great milestone in biochemistry” (Neville II, p. 274). “Pasteur’s first paper on fermentation contains most of the central theoretical and methodological features of his biological theory of fermentation, in particular the concept of fermentation as a product of the growth of yeast, the idea that air is a source of microscopic yeasts and other micro-organisms, and the notion of specificity, in which each fermentation could be traced to a specific micro-organism” (Dibner). “Pasteur’s concept of fermentation as a biological process challenged the chemical theory of fermentation put forth by Liebig, which Pasteur was able to disprove with his experiments on alcoholic and acetic fermentation” (Norman).
Provenance: The earlier paper is inscribed by Pasteur to the French physicist and chemist Pierre-Guillaume-Camille Forthomme (1821-84): “A Monsieur Forthomme, Professeur au lycée de Nancy, souvenir affectueux, L. Pasteur.”
“Pasteur’s memoir [‘Sur la Fermentation appelée lactique’] expressed the basic approach and point of view which informed all of his subsequent work on fermentation. After a historical introduction he began by claiming that “just as an alcoholic ferment exists–namely, brewer’s yeast–which is found wherever sugar breaks down into alcohol and carbonic acid–so too there is a special ferment–a lactic yeast–always present when sugar becomes lactic acid” … Throughout the memoir Pasteur more nearly assumed than proved that lactic yeast “is a living organism, … that its chemical action on sugar corresponds to its development and organization,” and that the nitrogenous substances in the fermenting medium served merely as its food. Nonetheless, his convictions were firm and his conception of fermentation was already remarkably complete … With two striking exceptions this memoir contains the central theoretical and methodological features of all of Pasteur’s work on fermentation–the biological conception of fermentation as the result of the activity of living microorganisms; the view that the substances in the fermenting medium serve as food for the causative microorganism and must therefore be appropriate to its nutritional requirements; the notion of specificity, according to which each fermentation can be traced to a specific microorganism; the recognition that particular chemical features of the medium can promote or impede the development of any one microorganism in it; the notion of competition among different microorganisms for the aliments contained in the media; the assumption that air might be the source of the microorganisms that appear in fermentations; and the technique of directly and actively sowing the microorganism presumed responsible for a given fermentation in order to isolate and purify it. The two missing features, which soon completed Pasteur’s basic conception, were the technique of cultivating microorganisms (and thereby producing fermentations) in a medium free of organic nitrogen and his notion of fermentation as “life without air” …
“In December 1857 Pasteur published the first in a series of abstracts, notes, and letters on alcoholic fermentation that culminated in a long and classic memoir of 1860 [‘Memoire sur la Fermentation alcoolique’]. Divided into two major sections, dealing respectively with the fate of sugar and of yeast in alcoholic fermentation, it inflicted on the chemical theory what Duclaux called “a series of blows straight from the shoulder, delivered with agility and assurance.” Pasteur established that alcoholic fermentation invariably produces not only carbonic acid and ethyl alcohol–as was well known–but also appreciable quantities of glycerin and succine acid as well as trace amounts of cellulose, “fatty matters,” and “indeterminate products.” On the basis of these results, Pasteur emphasized the complexity of alcoholic fermentation and attacked the tendency of chemists since Lavoisier to depict it as the simple conversion of sugar into carbonic acid and alcohol. If the alleged simplicity of the process had formerly been seen as evidence of its chemical nature, he argued, then its actual complexity ought now to be seen as evidence of its dependence on the activity of a living organism. In truth, the complexity of alcoholic fermentation was such as to prevent the writing of a complete equation for it, a fact which was only to be expected, since chemistry was “too little advanced to hope to put into a rigorous equation a chemical act correlative with a vital phenomenon.”
“However impressive this line of attack against the chemical theory, an even more decisive mode of argument derived from Pasteur’s ability to produce yeast and alcoholic fermentation in a medium free of organic nitrogen. To a pure solution of cane sugar he added only an ammonium salt and the minerals obtained by incineration of yeast, then sprinkled in a trace of pure brewer’s yeast. Although the experiment was difficult and not always successful, this method could produce an alcoholic fermentation accompanied by growth and reproduction in the yeast and the evolution of all the usual products. If any one constituent of this medium were eliminated, no alcoholic fermentation took place. Obviously, argued Pasteur, the yeast must grow and develop in this mineral medium by assimilating its nitrogen from the ammonium salt, its mineral constituents from the yeast ash, and its carbon from the sugar. In fact, it is precisely the capacity of yeast to assimilate combined carbon from sugar that explains why it can decompose sugar into carbonic acid and alcohol” (DSB).
“Educated at the École Normale Supérieure, Forthomme was professor of physics at the high school of Nancy for many years (where he had [Henri] Poincaré as a student), prior to obtaining the chair of the faculty of chemistry [at the University of Nancy] in 1869. Well-known to the intellectual circles of Nancy, he was a member of the municipal council and would sponsor the candidature of Léon Poincaré [Henri’s father] to the Académie de Stanislas in 1862” (de Paz & DiSalle, Poincaré, Philosopher of Science, p. 8).
Much-abridged versions of the two papers appeared in the Comptes rendus de l'Académie des Sciences (Paris) in 1857; ‘Mémoire sur la Fermentation appelée lactique’ appeared almost simultaneously in the Mémoires de la Société des Sciences, de l'Agriculture et des Arts de Lille, 2nd series, 5 (1858). The only recorded offprints were prepared from the Annales de Chimie et de Physique.
Dibner 198; Garrison-Morton 2472 and Horblit 82 (abridged version); Norman 1653 (offprint), all for the earlier paper. Brock, Milestones in Microbiology, pp. 27-30.
8vo (219 x 135 mm), pp [1-3] 4-106;  2-15 [1:blank but with manuscript annotations, probably by Forthomme], both offprints bound together in early 20th century cloth, first and final leaf with some browning.