The life of Pasteur

by René Vallery-Radot

Six days later, on March 16, whilst the Court was celebrating the birthday of the Prince Imperial, Napoleon III, who, on reading Pasteur’s article, had expressed his intention of consulting not only Pasteur, but also Milne-Edwards, Claude Bernard, and Henri Sainte Claire Deville, asked the four scientists to his study to meet Rouher, Marshal Vaillant and Duruy, perhaps the three men of the Empire who were best qualified to hear them. The Emperor in his slow, detached manner, invited each of his guests to express his opinion on the course to follow. All agreed in regretting that pure science should be given up. When Rouher said that it was not to be wondered at that the reign of applied science should follow that of pure science, “But if the sources of applications are dried up!” interposed the Emperor hastily. Pasteur, asked to express his opinion (he had brought with him notes of what he wished to say), recalled the fact that the Natural History Museum and the Ecole Polytechnique, which had had so great a share in the scientific movement of the early part of the century, were no longer in that heroic period. For the last twenty years the industrial prosperity of France had induced the cleverest Polytechnicians to desert higher studies and theoretical science, though the source of all applications was to be found in theory. The Ecole Polytechnique was obliged now to recruit its teaching staff outside, chiefly among Normaliens. What was to be done to train future scientists? This: to maintain in Paris, during two or three years, five or six graduates chosen from the best students of the large schools as curators or preparation masters, doing at the Ecole Polytechnique and other establishments what was done at the Ecole Normale. Thanks to that special institution, science and higher teaching would have a reserve of men who would become an honour to their country. Next, and this was the second point, no less important than the first, scientists should be given resources better appropriated to the pursuit of their work; as in Germany, for instance, where a scientist would leave one university for another on the express condition that a laboratory should be built for him, “a laboratory,” said Pasteur, “usually magnificent, not in its architecture (though sometimes that is the case, a proof of the national pride in scientific glory), but in the number and perfection of its appliances. Besides,” he added, “foreign scientists have their private homes adjoining their laboratories and collections,” indeed a most pressing inducement to work.

Pasteur did not suggest that a scientist should give up teaching; he recognized, on the contrary, that public teaching forces him to embrace in succession every branch of the science he teaches. “But let him not give too frequent or too varied lectures! they paralyze the faculties,” he said, being well aware of the cost of preparing classes. He wished that towns should be interested in the working and success of their scientific establishments. The Universities of Paris, of Lyons, of Strasburg, of Montpellier, of Lille, of Bordeaux, and of Toulouse, forming as a whole the University of France, should be connected to the neighbourhood which they honour in the same way that German universities are connected with their surroundings.

Pasteur had the greatest admiration for the German system: popular instruction liberally provided, and, above it, an intellectually independent higher teaching. Therefore, when the University of Bonn resolved in that year, 1868, to offer him as a great homage the degree of M.D. on account of his works on micro-organisms, he was proud to see his researches rated at their proper value by a neighbouring nation. He did not then suspect the other side of German nature, the military side, then very differently preoccupied. Those preoccupations were pointed out to the French Government in a spirit of prophecy, and with some patriotic anguish, by two French officers, General Ducrot, commanding since 1865 the 6th Military Division, whose headquarters were at Strasburg, and Colonel Baron Stoffel, military attaché in Prussia since 1866. Their warnings were so little heeded that some Court intrigues were even then on foot to transfer General Ducrot from Strasburg to Bourges, so that he might no longer worry people with his monomania of Prussian ambition.

On March 10, the evening of the day when the Emperor decided upon making improvements, and when Duruy felt assured, thanks to the promised allowances, that he could soon offer to French professors “the necessary appliances with which to compete with their rivals beyond the Rhine,” Pasteur started for Alais, where his arrival was impatiently awaited, both by partisans and adversaries of his experiments on silkworm disease. He would much have liked to give the results of his work in his inaugural lecture at the Sorbonne. “But,” he wrote to Duruy, “these are but selfishly sentimental reasons, which must be outweighed by the interest of my researches.”

On his arrival he found to his joy that those who had practised seeding according to his rigorous prescriptions had met with complete success. Other silkworm cultivators, less well advised, duped by the decoying appearances of certain broods, had not taken the trouble to examine whether the moths were corpuscled; they were witnesses and victims of the failure Pasteur had prophesied. He now looked upon pébrine as conquered; but flachery remained, more difficult to prevent, being greatly dependent upon the accidents which traverse the life of a silkworm. Some of those accidents happen in spite of all precautions, such as a sudden change of temperature or a stormy day; but at least the leaves of the mulberry tree could be carefully kept from fermentation, or from contamination by dusts in the nurseries. Either of those two causes was sufficient to provoke a fatal disorder in silkworms, the feeding of which is so important that they increase to fifteen thousand times their own weight during the first month of their life. Accidental flachery could therefore be avoided by hygienic precautions. In order to prevent it from becoming hereditary, Pasteur—who had pointed out that the micro-organism which causes it develops at first in the intestinal canal of the worm and then becomes localized in the digestive cavity of the chrysalis—advised the following means of producing a healthy strain of silkworms: “This means,” writes M. Gernez, Pasteur’s assiduous collaborator in these studies, “does not greatly complicate operations, and infallibly ensures healthy seed. It consists in abstracting with the point of a scalpel a small portion of the digestive cavity of a moth, then mixing it with a little water and examining it with a microscope. If the moths do not contain the characteristic micro-organism, the strain they come from may unhesitatingly be considered as suitable for seeding. The flachery micro-organism is as easily recognized as the pébrine corpuscle.”

The seed merchants, made uneasy by these discoveries which so gravely jeopardized their industry, spread the most slanderous reports about them and made themselves the willing echo of every imposture, however incredible. M. Laurent wrote to his daughter, Madame Pasteur, in a letter dated from Lyons (June 6): “It is being reported here that the failure of Pasteur’s process has excited the population of your neighbourhood so much that he has had to flee from Alais, pursued by infuriated inhabitants throwing stones after him.” Some of these legends lingered in the minds of ignorant people.

Important news came from Paris to Pasteur in July, and on the 27th he was able to write to Raulin: “The building of my laboratory is going to be begun! the orders are given, and the money found. I heard this two days ago from the Minister.” 30,000 francs had been allowed for the work by the Minister of Public Instruction, and an equal sum was promised by the Minister of the Emperor’s household. Duruy was preparing at the same time a report on two projected decrees concerning laboratories for teaching purposes and for research. “The laboratory for research,” wrote Duruy, “will not be useful to the master alone, but more so even to the students, thus ensuring the future progress of science. Students already provided with extensive theoretical knowledge will be initiated in the teaching laboratories into the handling of instruments, elementary manipulations, and what I may call classical practice; this will gather them around eminent masters, from whom they will learn the art of observation and methods of experiment.... It is with similar institutions that Germany has succeeded in obtaining the great development of experimental science which we are now watching with an anxious sympathy.”

Pasteur returned to Paris with his enthusiastic mind overflowing with plans of all kinds of research. He wanted to be there when the builders began their work on the narrow space in the Rue d’Ulm. He wrote to Raulin on August 10, asking his opinion as he would that of an architect; then went on to say, planning out his busy holidays: “I shall leave Paris on the 16th with my wife and children to spend three weeks at the seaside, at St. George’s, near Bordeaux. If you were free at the end of the month, or at the beginning of September, I wish you could accompany me to Toulon, where experiments on the heating of wines will be made by the Minister of the Navy. Great quantities of heated and of non-heated wine are to be sent to Gabon so as to test the process; at present our colonial crews have to drink mere vinegar. A commission of very enlightened men is formed and has begun studies with which it seems satisfied.... See if you can join me at Bordeaux, where I shall await a notice from the chairman of the Commission, M. de Lapparent, director of naval construction at the Ministry of Marine.”

The Commission mentioned by Pasteur had been considering for the last two years the expediency of applying the heating process to wines destined for the fleet and to the colonies. A first trial was made at Brest on the contents of a barrel of 500 litres, half of which was heated. Then the two wines were sealed in different barrels and placed in the ship Jean Bart, which remained away from the harbour for ten months. When the vessel returned, the Commission noted the limpidity and mellowness of the heated wine, adding in the official report that the wine had acquired the attractive colour peculiar to mature wines. The non-heated wine was equally limpid, but it had an astringent, almost acid flavour. It was still fit to drink, said the report, but it were better to consume it rapidly, as it would soon be entirely spoilt. Identical results were observed in some bottles of heated and non-heated wines at Rochefort and Orleans.

M. de Lapparent now organized a decisive experiment, to take place under Pasteur’s superintendence. The frigate la Sibylle started for a tour round the world with a complete cargo of heated wine. Pasteur, who returned to Arbois for a short rest before going back to Paris, wrote from there to his early confidant, Chappuis (September 21, 1868): “I am quite satisfied with my experiments at Toulon and with the success of the Navy tests. We heated 650 hectolitres in two days; the rapidity of this operation lends itself to quick and considerable commissariat arrangements. Those 650 hectolitres will be taken to the West Coast of Africa, together with 50 hectolitres of the same wine non-heated. If the trial succeeds, that is to say if the 650 hectolitres arrive and can be kept without alteration, and if the 50 hectolitres become spoilt (I feel confident after the experiments I have made that such will be the result), the question will be settled, and, in the future, all the wine for the Navy will be ensured against disease by a preliminary heating. The expense will not be more than five centimes per hectolitre. The result of these experiments will have a great influence on the trade, ever cautious and afraid of innovations. Yet we have seen, at Narbonne in particular, some heating practised on a large scale by several merchants who have spoken to me very favourably about it. The exportation of our French wines will increase enormously, for at present our ordinary table wines lend themselves to trade with England and other countries beyond seas, but only by means of a strong addition of alcohol, which raises their price and tampers with their hygienic qualities.”