Pasteur, his mind full of ideas, started for the International Medical Congress, which was now to take place at Copenhagen. Sixteen hundred members arranged to attend, and nearly all of them found on arriving that they were to be entertained in the houses of private individuals. The Danes carry hospitality to the most generous excess; several of them had been learning French for the last three years, the better to entertain the French delegates. Pasteur’s son, then secretary of the French Legation at Copenhagen, had often spoken to his father with appreciative admiration of those Northerners, who hide deep enthusiasm under apparent calmness, almost coldness.
The opening meeting took place on August 10 in the large hall of the Palace of Industry; the King and Queen of Denmark and the King and Queen of Greece were present at that impressive gathering. The President, Professor Panum, welcomed the foreign members in the name of his country; he proclaimed the neutrality of Science, adding that the three official languages to be used during the Congress would be French, English, and German. His own speech was entirely in French, “the language which least divides us,” he said, “and which we are accustomed to look upon as the most courteous in the world.”
The former president of the London Congress, Sir James Paget, emphasized the scientific consequences of those triennial meetings, showing that, thanks to them, nations may calculate the march of progress.
Virchow, in the name of Germany, developed the same idea.
Pasteur, representing France, showed again as he had done at Milan in 1878, in London in 1881, at Geneva in 1882, and quite recently in Edinburgh, how much the scientist and the patriot were one in him.
“In the name of France,” said he, “I thank M. le Président for his words of welcome.... By our presence in this Congress, we affirm the neutrality of Science ... Science is of no country.... But if Science has no country, the scientist must keep in mind all that may work towards the glory of his country. In every great scientist will be found a great patriot. The thought of adding to the greatness of his country sustains him in his long efforts, and throws him into the difficult but glorious scientific enterprises which bring about real and durable conquests. Humanity then profits by those labours coming from various directions....”
At the end of the meeting Pasteur was presented to the King. The Queen of Denmark and the Queen of Greece, regardless of etiquette, walked towards him, “a signal proof,” wrote a French contemporary, “of the esteem in which our illustrious countryman is held at the Danish Court.”
Five general meetings were to give some of the scientists an opportunity of expounding their views on subjects of universal interest. Pasteur was asked to read the first paper; his audience consisted, besides the members of the Congress, of many other men interested in scientific things, who had come to hear him describe the steps by which he had made such secure progress in the arduous question of hydrophobia. He began by a declaration of war against the prejudice by which so many people believe that rabies can occur spontaneously. Whatever the pathological, physiological, or other conditions may be under which a dog or another animal is placed, rabies never appears if the animal has not been bitten or licked by another rabid animal; this is so truly the case that hydrophobia is unknown in certain countries. In order to preserve a whole land from the disease, it is sufficient that a law should, as in Australia, compel every imported dog to be in quarantine for several months; he would then, if bitten by a mad dog before his departure, have ample time to die before infecting other animals. Norway and Lapland are equally free from rabies, a few good prophylactic measures being sufficient to avert the scourge.
It will be objected that there must have been a first rabid dog originally. “That,” said Pasteur, “is a problem which cannot be solved in the present state of knowledge, for it partakes of the great and unknown mystery of the origin of life.”
The audience followed with an impassioned curiosity the history of the stages followed by Pasteur on the road to his great discovery: the preliminary experiments, the demonstration of the fact that the rabic virus invades the nervous centres, the culture of the virus within living animals, the attenuation of the rabic virus when passed from dogs to monkeys, and simultaneously with this graduated attenuation, a converse process by successive passages from rabbit to rabbit, the possibility of obtaining in this way all the degrees of virulence, and finally the acquired certainty of having obtained a preventive vaccine against canine hydrophobia.