The election was at hand. Pasteur wrote (March 11): “My dear father, I am certain to fail.” He thought he might count upon twenty votes; thirty were necessary. He resigned himself philosophically. His candidature would at any rate bring his works into greater prominence. In spite of a splendid report by Senarmont, enumerating the successive steps by which Pasteur had risen since his first discoveries concerning the connection between internal structure and external crystalline forms, Pasteur only obtained sixteen votes.
On his return to Lille he set to work with renewed energy; he took up again his study of fermentations, and in particular that of sour milk, called lactic fermentation; he made notes of his experiments day by day; he drew in a notebook the little globules, the tiny bodies that he found in a grey substance sometimes arranged in a zone. Those globules, much smaller than those of yeast, had escaped the observation of chemists and naturalists because it was easy to confound them with other products of lactic fermentation. After isolating and then scattering in a liquid a trace of that grey substance, Pasteur saw some well-characterized lactic fermentation appear. That matter, that grey substance was indeed the ferment.
Whilst all the writings of the chemists who followed in the train of Liebig and Berzelius united in rejecting the idea of an influence of life in the cause of fermentations, Pasteur recognized therein a phenomenon correlative to life. That special lactic yeast, Pasteur could see budding, multiplying, and offering the same phenomena of reproduction as beer yeast.
It was not to the Académie des Sciences, as is generally believed, that Pasteur sent the paper on lactic fermentation, the fifteen pages of which contained such curious and unexpected facts. With much delicacy of feeling, Pasteur made to the Lille Scientific Society this communication (August, 1857) which the Académie des Sciences only saw three months later.
How was it that he desired to leave this Faculty at Lille to which he had rendered such valuable service? The Ecole Normale was going through difficult times. “In my opinion,” wrote Pasteur with a sadness that betrayed his attachment to the great school, “of all the objects of care to the authorities, the Ecole Normale should be the first; it is now but the shadow of its former self.” He who so often said, “Do not dwell upon things already acquired!” thought that the Lille Faculty was henceforth sure of its future and needed him no longer. Was it not better to come to the assistance of the threatened weak point? At the Ministry of Public Instruction his wish was understood and approved of. Nisard had just been made Director of the Ecole Normale with high and supreme powers; his sub-director of literary studies was M. Jacquinet. The administration was reserved for Pasteur, who was also entrusted with the direction of the scientific studies. To that task were added “the surveillance of the economic and hygienic management, the care of general discipline, intercourse with the families of the pupils and the literary or scientific establishments frequented by them.”