The theories of Berzelius and of Liebig then reigned supreme. To the mind of Berzelius, the Swedish chemist, fermentation was due to contact. It was said that there was a catalytic force. In his opinion, what Cagniard-Latour believed he had seen, was but “an immediate vegetable principle, which became precipitated during the fermentation of beer, and which, in precipitating, presented forms analogous to the simpler forms of vegetable life, but formation does not constitute life.”
In the view of the German chemist Liebig, chemical decomposition was produced by influence: the ferment was an extremely alterable organic substance which decomposed, and in decomposing set in motion, by the rupture of its own elements, the molecules of the fermentative matter; it was the dead portion of the yeast, that which had lived and was being altered, which acted upon the sugar. These theories were adopted, taught, and to be found in all treatises on chemistry.
A vacancy at the Académie des Sciences took Pasteur away from his students for a time and obliged him to go to Paris. Biot, Dumas, Balard and Senarmont had insisted upon his presenting himself in the section of mineralogy. He felt himself unfit for the candidature. He was as incapable of election manœuvres as he was full of his subject when he had to convince an interlocutor or to interest an audience in his works on crystallography. (These works had just procured the bestowal on him of the great Rumford medal, conferred by the London Royal Society.) During this detested canvassing campaign he had one happy day: he was present on February 5, 1857, at the reception of Biot by the Académie Française.
Biot, who had entered the Académie des Sciences fifty-four years earlier, and was now the oldest member of the Institute, took advantage of his great age to distribute, in the course of his speech, a good deal of wise counsel, much applauded by Pasteur from the ranks of the audience. Biot, with his calm irony, aimed this epigram at men of science who disdained letters: “Their science was not the more apparent through their want of literary culture.” He ended by remarks which formed a continuation of his last letter to Pasteur’s father. Making an appeal to those whose high ambition is to consecrate themselves to pure science, he proudly said: “Perhaps your name, your existence will be unknown to the crowd. But you will be known, esteemed, sought after by a small number of eminent men scattered over the face of the earth, your rivals, your peers in the intellectual Senate of minds; they alone have the right to appreciate you and to assign to you your rank, a well-merited rank, which no princely will, no popular caprice can give or take away, and which will remain yours as long as you remain faithful to Science, which bestows it upon you.”