The sharpest attacks came from Germany. The Record of the Works of the German Sanitary Office had led, under the direction of Dr. Koch and his pupils, a veritable campaign against Pasteur, whom they declared incapable of cultivating microbes in a state of purity. He did not even, they said, know how to recognize the septic vibrio, though he had discovered it. The experiments by which hens contracted splenic fever under a lowered temperature after inoculation signified nothing. The share of the earthworms in the propagation of charbon, the inoculation into guinea-pigs of the germs found in the little cylinders produced by those worms followed by the death of the guinea-pigs, all this they said was pointless and laughable. They even contested the preserving influence of vaccination.
Whilst these things were being said and written, the Veterinary School of Berlin asked the laboratory of the Ecole Normale for some charbon vaccine. Pasteur answered that he wished that experiments should be made before a commission nominated by the German Government. It was constituted by the Minister of Agriculture and Forests, and Virchow was one of the members of it. A former student of the Ecole Normale—who, after leaving the school first on the list of competitors for the agrégation of physical science, had entered the laboratory—one in whom Pasteur founded many hopes, Thuillier, left for Germany with his little tubes of attenuated virus. Pasteur was not satisfied; he would have liked to meet his adversaries face to face and oblige them publicly to own their defeat. An opportunity was soon to arise. He had come to Arbois, as usual, for the months of August and September, and was having some alterations made in his little house. The tannery pits were being filled up. “It will not improve the house itself,” he wrote to his son, “but it will be made brighter and more comfortable by having a tidy yard and a garden along the riverside.”
The Committee of the International Congress of Hygiene, which was to meet at Geneva, interrupted these peaceful holidays by inviting Pasteur to read a paper on attenuated virus. As a special compliment, the whole of one meeting, that of Tuesday, September 5, was to be reserved for his paper only. Pasteur immediately returned to work; he only consented under the greatest pressure to go for a short walk on the Besançon road at five o’clock every afternoon. After spending the whole morning and the whole afternoon sitting at his writing table over laboratory registers, he came away grumbling at being disturbed in his work. If any member of his family ventured a question on the proposed paper, he hastily cut them short, declaring that he must be let alone. It was only when Mme. Pasteur had copied out in her clear handwriting all the little sheets covered with footnotes, that the contents of the paper became known.
When Pasteur entered the Congress Hall, great applause greeted him on every side. The seats were occupied, not only by the physicians and professors who form the usual audience of a congress, but also by tourists, who take an interest in scientific things when they happen to be the fashion.
Pasteur spoke of the invitation he had received. “I hastened to accept it,” he said, “and I am pleased to find myself the guest of a country which has been a friend to France in good as in evil days. Moreover, I hoped to meet here some of the contradictors of my work of the last few years. If a congress is a ground for conciliation, it is in the same degree a ground for courteous discussion. We all are actuated by a supreme passion, that of progress and of truth.”
Almost always, at the opening of a congress, great politeness reigns in a confusion of languages. Men are seen offering each other pamphlets, exchanging visiting cards, and only lending an inattentive ear to the solemn speeches going on. This time, the first scene of the first act suspended all private conversation. Pasteur stood above the assembly in his full strength and glory. Though he was almost sixty, his hair had remained black, his beard alone was turning grey. His face reflected indomitable energy; if he had not been slightly lame, and if his left hand had not been a little stiff, no one could have supposed that he had been struck with paralysis fourteen years before. The feeling of the place France should hold in an International Congress gave him a proud look and an imposing accent of authority. He was visibly ready to meet his adversaries and to make of this assembly a tribunal of judges. Except for a few diplomats who at the first words exchanged anxious looks at the idea of possible polemics, Frenchmen felt happy at being better represented than any other nation. Men eagerly pointed out to each other Dr. Koch, twenty-one years younger than Pasteur, who sat on one of the benches, listening, with impassive eyes behind his gold spectacles.
Pasteur analysed all the work he had done with the collaboration of MM. Chamberland, Roux, and Thuillier. He made clear to the most ignorant among his hearers his ingenious experiments either to obtain, preserve or modify the virulence of certain microbes. “It cannot be doubted,” he said, “that we possess a general method of attenuation.... The general principles are found, and it cannot be disbelieved that the future of those researches is rich with the greatest hopes. But, however obvious a demonstrated truth may be, it has not always the privilege of being easily accepted. I have met in France and elsewhere with some obstinate contradictors.... Allow me to choose amongst them the one whose personal merit gives him the greatest claims to our attention, I mean Dr Koch, of Berlin.”
Pasteur then summed up the various criticisms which had appeared in the Record of the Works of the German Sanitary Office. “Perhaps there may be some persons in this assembly,” he went on, “who share the opinions of my contradictors. They will allow me to invite them to speak; I should be happy to answer them.”
Koch, mounting the platform, declined to discuss the subject, preferring, he said, to make answer in writing later on. Pasteur was disappointed; he would have wished the Congress, or at least a Commission designated by Koch, to decide on the experiments. He resigned himself to wait. On the following days, as the members of the Congress saw him attending meetings on general hygiene, school hygiene, and veterinary hygiene, they hardly recognized in the simple, attentive man, anxious for instruction, the man who had defied his adversary. Outside the arena, Pasteur became again the most modest of men, never allowing himself to criticize what he had not thoroughly studied. But, when sure of his facts, he showed himself full of a violent passion, the passion of truth; when truth had triumphed, he preserved not the least bitterness of former struggles.
That day of the 5th September was remembered in Geneva. “All the honour was for France,” wrote Pasteur to his son; “that was what I had wished.”