pasteur, on his return, spent forty-eight hours in strasburg, which was for him full of memories of his laborious days at the faculty of that town, between 1848 and 1854, at a time when rivalry already existed between france and germany, a generous rivalry of moral and intellectual effort. he then heard for the first time of the threatening war; all his hopes of progress founded on peace, through scientific discoveries, began to crumble away, and his disappointment was embittered by the recollection of many illusions.

never was more cruel rebuff given to the generous efforts of a policy of sentiment: after having laid the foundation of the independence and unity of italy, france had sympathized with germany’s desire for unity, and few of the counsellors, or even the adversaries of the empire, would not have defended this idea, which was supposed to lead to civilization. during that period of anxious waiting (beginning of july, 1870), when the most alarming news was daily published in strasburg, it did not occur to any one to look back upon quotations from papers only a few years old, though in that very town a pamphlet might have been found, written by edmond about in 1860, and containing the following words—

“let germany become united! france has no dearer or more ardent desire, for she loves the german nation with a disinterested friendship. france is not alarmed at seeing the formation of an italian nation of 26,000,000 men in the south; she need not fear to see 32,000,000 germans found a great people on the eastern frontier.”

proud to be first to proclaim the rights of nations; influenced by mingled feelings of kindliness, trustfulness, optimism and a certain vanity of disinterestedness, france, who loves to be loved, imagined that the world would be grateful for her{178} international sociability, and that her smiles were sufficient to maintain peace and joy in europe.

far from being alarmed by certain symptoms in her neighbours, she voluntarily closed her eyes to the man?uvres of the prussian troops, her ears to the roar of the artillery practice constantly heard across her eastern frontier; in 1863 patrols of german cavalry had come as far as wissemburg. but people thought that germany was “playing soldiers.” duruy, who shared at that time the general delusion, wrote in some traveller’s notes published in 1864: “we have had your german rhine, and though you have garnished it with bristling fortresses and cannon turning france-wards, we do not wish to have it again, ... for the time for conquests is past. conquests shall only now be made with the free consent of nations. too much blood has been poured into the rhine! what an immense people would arise if they who were struck down by the sword along its banks could be restored to life!”

after the thunderclap of sadowa, the french government, believing, in its infatuation, that it was entitled to a share of gratitude and security, asked for the land along the rhine as far as mayence; this territorial aggrandizement might have compensated for prussia’s redoubtable conquests. the refusal was not long in coming. the rhenish provinces immediately swarmed with prussian troops. the emperor, awaking from his dream, hesitating to make war, sent another proposition to prussia: that the rhenish provinces should become a buffer state. the same haughty answer was returned. france then hoped for the cession of luxemburg, a hope all the more natural in that the populations of luxemburg were willing to vote for annexation to france, and such a policy would have been in accordance with the rights of nations. but this request, apparently entertained at first by prussia, was presently hampered by intrigues which caused its rejection. duped, not even treated as an arbiter, but merely as a contemptible witness, france dazzled herself for a moment with the brilliant exhibition of 1867. but it was a last and splendid flash; the word which is the bane of nations and of sovereigns, “to-morrow,” was on the lips of the ageing emperor. the reform in the french army, which should have been bold and immediate, was postponed and afterwards begun jerkily and unmethodically. prussia however affected to be alarmed. then irritation at having been duped, the evidence{179} of a growing peril, a lingering hope in the military fortune of france—everything conspired to give an incident, provoked by prussia, the proportions of a casus belli. but, in spite of so many grievances, people did not yet believe in this sudden return to barbarism. the imperial policy had indeed been blindly inconsistent; after opening a wide prospect of unity before the german people it had been thought possible to say “no further than the main,” as if the impetuous force of a popular movement could be arrested after once being started. france suddenly opened her eyes to her danger and to the failure of her policy. but if a noble sentiment of generosity had been mingled with the desire to increase her territory without shedding a drop of blood, she had had the honour of being in the vanguard of progress. were great ideas of peace and human brotherhood about to be engulfed in a war which would throw europe into an era of violence and brutality?

pasteur, profoundly saddened, could not bear to realize that his ideal of the peaceful and beneficent destiny of france was about to vanish; he left strasburg—never to return to it—a prey to the most sombre thoughts.

when he returned to paris, he met sainte claire deville, who had come back from a scientific mission in germany, and who had for the first time lost his brightness and optimism. the war appeared to him absolutely disastrous. he had seen the prussian army, redoubtable in its skilful organization, closing along the frontier; the invasion was certain, and there was nothing to stay it. everything was lacking in france, even in arsenals like strasburg. at toul, on the second line of fortifications, so little attention was paid to defence that the government had thought that the place could be used as a dép?t for the infantry and cavalry reserves, who could await there the order for crossing the rhine.

“ah! my lads, my poor lads!” said sainte claire deville to his ecole normale students, “it is all up with us!” and he was seen, between two experiments, wiping his eyes with the comer of his laboratory apron.

the students, with the ordinary confidence of youth, could not believe that an invasion should be so imminent. however, in spite of the privilege which frees normaliens from any military service in exchange for a ten years’ engagement at the university, they put patriotic duty above any future university appointments, and entered the ranks as private{180} soldiers. those who had been favoured by being immediately incorporated in a battalion of chasseurs à pied the dép?t of which was at vincennes, spent their last evening—their vigil as they called it—in the drawing-room of the sub-director of the ecole, bertin. sainte claire deville and pasteur were there, also duruy, whose three sons had enlisted. pasteur’s son, aged eighteen, was also on the eve of his departure.

every one of the students at the ecole normale enlisted, some as chasseurs à pied, some in a line regiment, others with the marines, in the artillery, even with the franc tireurs. pasteur wished to be enrolled in the garde nationale with duruy and bertin, but he had to be reminded that a half-paralysed man was unfit for service. after the departure of all the students, the ecole normale fell into the silence of deserted houses. m. bouillier, the director, and bertin decided to turn it into an ambulance, a sort of home for the normaliens who were stationed in various quarters of paris.

pasteur, unable to serve his country except by his scientific researches, had the firm intention of continuing his work; but he was overwhelmed by the reverses which fell upon france, the idea of the bloodshed and of his invaded country oppressed him like a monomania.

“do not stay in paris,” bertin said to him, echoed by dr. godélier. “you have no right to stay; you would be a useless mouth during the siege,” he added, almost cheerfully, earnestly desiring to see his friend out of harm’s way. pasteur allowed himself to be persuaded, and started for arbois on september 5, his heart aching for the sorrows of france.

some notes and letters enable us to follow him there, in the daily detail of his life, amongst his books, his plans of future work, and now and then his outbursts of passionate grief. he tried to return to the books he loved, to feel over again the attraction of “all that is great and beautiful” to quote a favourite phrase. he read at that time laplace’s exposition du système du monde, and even copied out some fragments, general ideas, concurring with his own. the vision of a galileo or a newton rising through a series of inductions from “particular phenomena to others more far-reaching, and from those to the general laws of nature,” on this earth, “itself so small a part of the solar system, and disappearing entirely in the immensity of the heavens, of which that system is but an unimportant corner,”—that vision enveloped pasteur{181} with the twofold feeling with which every man must be imbued: humility before the great mystery, and admiration for those who, raising a corner of the veil, prove that genius is divinely inspired. such reading helped pasteur through the sad time of anxious waiting, and he would repeat as in brighter days, “laboremus.”

but sometimes, when he was sitting quietly with his wife and daughter, the trumpet call would sound, with which the arbois crier preceded the proclaiming of news. then everything was forgotten, the universal order of things of no account, and pasteur’s anguished soul would concentrate itself on that imperceptible comer of the universe, france, his suffering country. he would go downstairs, mix with groups standing on the little bridge across the cuisance, listen breathlessly to the official communication, and sadly go back to the room where the memories of his father only emphasized the painful contrast with the present time. in the most prominent place hung a large medallion of general bonaparte, by the franc-comtois huguenin, the habit of authority visible in the thin energetic face; then a larger effigy in bronzed plaster of napoleon in profile, in a very simple uniform; by the mantelpiece a lithograph of the little king of rome with his curly head; on the bookshelves, well within reach, books on the great epoch, read over and over again by the old soldier who had died in the humble room which still reflected some of the imperial glory.

that glory, that legend had enveloped the childhood and youth of pasteur, who, as he advanced in life, still preserved the same enthusiasm. his imagination pictured the emperor, calm in the midst of battles, or reviewing his troops surrounded by an escort of field marshals, entering as a sovereign a capital not his own, then overwhelmed by numbers at waterloo, and finally condemned to exile and inactivity, and dying in a long drawn agony. glorious or lugubrious, those visions came back to him with poignant insistency in those days of september, 1870. what was waterloo compared to sedan! the departure for st. helena had the grandeur of the end of an epic; it seemed almost enviable by the side of that last episode of the second empire, when napoleon iii, vanquished, spared by the death which he wooed, left sedan by the donchery road to enter the cottage where bismarck was to inform him of the rendezvous given by the king of prussia.

the emperor had now but a shadow of power, having made{182} the empress regent before he left paris; it was therefore not the sword of france, but his own, that he was about to surrender. but he thought he might hope that the king of prussia would show clemency to the french army and people, having many times declared that he made war on the emperor and not on france.

“can it be credited,” said bismarck, speaking afterwards of that interview, “that he actually believed in our generosity!” the chancellor added, speaking of that somewhat protracted tête-à-tête, “i felt as i used to in my youth, when my partner in a cotillon was a girl to whom i did not quite know what to say, and whom nobody would fetch away for a turn!”

napoleon iii and the king of prussia met in the chateau of bellevue, in the neighbourhood of sedan, opposite a peninsula henceforth known by the sad name of “camp of misery.” the emperor looked for the last time upon his 83,000 soldiers, disarmed, starving, waiting in the mud for the prussian escort which was to convey them as prisoners far beyond the rhine. wilhelm did not even pronounce the word peace.

jules favre, taking possession on september 6 of the department of foreign affairs, recalled to the diplomatic agents the fall of the empire and the words of the king of prussia; then in an unaccustomed outburst of eloquence exclaimed: “does the king of prussia wish to continue an impious struggle which will be as fatal to him as to us? does he wish to give to the world in the nineteenth century the cruel spectacle of two nations destroying each other and forgetful of human feelings, of reason and of science, heaping up ruin and death? let him then assume the responsibility before the world and before posterity!” and then followed the celebrated phrase with which he has been violently and iniquitously reproached, and which expressed the unanimous sentiment of france: “we will not concede one inch of our territory nor a stone of our fortifications.”

bismarck refused the interview jules favre asked of him (september 10), under the pretext that the new government was irregular. the enemy was coming nearer and nearer to paris. the french city was resolved to resist; thousands upon thousands of oxen were being corralled in the bois de boulogne; poor people from the suburbs were coming to take refuge in the city. on the place de la concorde, the statue which repre{183}sents the city of strasburg was covered with flowers and flags, and seemed to incarnate the idea of the patrie itself.

articles and letters came to arbois in that early september, bringing an echo of the sorrows of paris. pasteur was then reading the works of general foy, wherein he found thoughts in accordance with his own, occasionally copying out such passages as the following: “right and might struggle for the world; right, which constitutes and preserves society; might, which overcomes nations and bleeds them to death.”

general foy fought for france during twenty-five years, and, writing in 1820, recalled with a patriotic shudder the horrors of foreign invasions. long after peace was signed, by a chance meeting in a street in paris, general foy found himself face to face with wellington. the sight was so odious to him that he spoke of this meeting in the chambre with an accent of sorrowful humiliation which breathed the sadness of waterloo over the whole assembly. pasteur could well understand the long continued vibration of that suffering chord, he, who never afterwards could speak without a thrill of sorrow of that war which germany, in defiance of humanity, was inexcusably pursuing.

it was the fourth time in less than a hundred years that a prussian invasion overflowed into france. but instead of 42,000 prussians, scattered in 1792 over the sacred soil of the patrie—pasteur pronounced the word with the faith and tenderness of a true son of france—there were now 518,000 men to fight 285,000 french.

the thought that they had been armed in secret for the conquest of neighbouring lands, the memory of france’s optimism until that diplomatic incident, invented so that france might stumble over it, and the inaction of europe, inspired pasteur with reflections which he confided to his pupil raulin. “what folly, what blindness,” he wrote (september 17), “there are in the inertia of austria, russia, england! what ignorance in our army leaders of the respective forces of the two nations! we savants were indeed right when we deplored the poverty of the department of public instruction! the real cause of our misfortunes lies there. it is not with impunity—as it will one day be recognized, too late—that a great nation is allowed to lose its intellectual standard. but, as you say, if we rise again from those disasters, we shall again see our statesmen lose themselves in endless{184} discussions on forms of government and abstract political questions instead of going to the root of the matter. we are paying the penalty of fifty years’ forgetfulness of science, of its conditions of development, of its immense influence on the destiny of a great people, and of all that might have assisted the diffusion of light.... i cannot go on, all this hurts me. i try to put away all such memories, and also the sight of our terrible distress, in which it seems that a desperate resistance is the only hope we have left. i wish that france may fight to her last man, to her last fortress. i wish that the war may be prolonged until the winter, when, the elements aiding us, all these vandals may perish of cold and distress. every one of my future works will bear on its title page the words: ‘hatred to prussia. revenge! revenge!’”

there is a passage in the psalms where the captives of israel, led to babylonian rivers, weep at the memory of jerusalem. after swearing never to forget their country, they wish their enemies every misfortune, and hurl this last imprecation at babylon: “blessed shall he be that taketh thy children and throweth them against the stones.”[29] one of the most christlike souls of our time, henri perreyve, speaking of poland, of vanquished and oppressed nations, quoted this psalm and exclaimed: “o anger, man’s anger, how difficult it is to drive thee out of man’s heart! and how irresistible are the flames kindled by the insolence of injustice!” those flames were kindled in the soul of pasteur, full as it was of human tenderness, and they burst out in that sobbing cry of despair.

on that 17th of september, the day before paris was invested, jules favre made another attempt to obtain peace. he published an account of that interview which took place at the chateau of ferrières, near meaux; this printed account reached every town in france, and was read with grief and anger.

jules favre had deluded himself into thinking that victorious prussia would limit its demands to a war indemnity, probably a formidable one. but bismarck, besides the indemnity, intended to take a portion of french soil, and claimed strasburg first of all. “it is the key of the house; i must have it.” and with strasburg he wanted the whole department of the haut-rhin, that of the bas-rhin, metz, and a part of the department of moselle. jules favre, character{185}istically french, exhausted his eloquence in putting sentiment into politics, spoke of european rights, of the right of the people to dispose of themselves, tried to bring out the fact that a brutal annexation was in direct opposition to the progress of civilization. “i know very well,” said bismarck, “that they (meaning the alsatians and lorrainers) do not want us; they will give us a deal of trouble, but we must annex them.” in the event of a future war prussia was to have the advantage. all this was said with an authoritative courtesy, an insolent tranquillity, through which contempt for men was visible, evidently the best means of governing them in bismarck’s eyes. as jules favre was pleading the cause of heroic strasburg, whose long resistance was the admiration of paris, “strasburg will now fall into our hands,” said bismarck coldly; “it is but a question for engineers; therefore i request that the garrison should surrender as prisoners of war.”

jules favre “leapt in his grief”—the words are his—but king wilhelm exacted this condition. jules favre, almost breaking down, turning away to hide the tears that welled into his eyes, ended the interview with these words: “it is an indefinite struggle between two nations who should go hand in hand.”

traces of this patriotic anguish are to be found in one of pasteur’s notebooks, as well as a circular addressed by jules favre to the diplomatic representatives in answer to certain points disputed by bismarck. pasteur admiringly took note of the following passage: “i know not what destinies fate has in store for us. but i do feel most deeply that if i had to choose between the present situation of france and that of prussia, i should decide for the former. better far our sufferings, our perils, our sacrifices, than the cruel and inflexible ambition of our foe.”

“we must preserve hope until the end,” wrote pasteur after reading the above, “say nothing to discourage each other, and wish ardently for a prolonged struggle. let us think of hopeful things; bazaine may save us.”... how many french hearts were sharing that hope at the very time when bazaine was preparing to betray metz, his troops and his flag!

“should we not cry: ‘happy are the dead!’” wrote pasteur a few days after the news burst upon france of that army lost without being allowed to fight, of that city of metz, the strongest in france, surrendered without a struggle!

through all pasteur’s anxieties about the war, certain obser{186}vations, certain projected experiments resounded in his mind like the hours that a clock strikes, unheeded but not unheard, in a house visited by death. he could not put them away from him, they were part of his very life.

any sort of laboratory work was difficult for him in the tanner’s house, which had remained the joint property of himself and his sister. his brother-in-law had continued joseph pasteur’s trade. pasteur applied his spirit of observation to everything around him, and took the opportunity of studying the fermentation of tan. he would ask endless questions, trying to discover the scientific reason of every process and every routine. whilst his sister was making bread he would study the raising of the crust, the influence of air in the kneading of the dough, and his imagination rising as usual from a minor point to the greatest problems, he began to seek for a means of increasing the nutritive powers of bread, and consequently of lowering its price.

the salut public of december 20 contained a notice on that very subject, which pasteur transcribed. the central commission of hygiene which included among its members sainte claire deville, wurtz, bouchardat and trélat, had tried, when dealing with this question of bread (a vital one during the siege), to prove to the parisians that bread is the more wholesome for containing a little bran. “with what emotion,” wrote pasteur, “i have just read all those names dear to science, greater now before their fellow-citizens and before posterity. why could i not share their sufferings and their dangers!” he would have added “and their work” if some of the académie des sciences reports had reached him.

the history of the academy during the war is worthy of brief mention. moreover it was too deeply interesting to pasteur, too constantly in his thoughts, not to be considered as forming part of his biography.

during the first period, the academy, imagining, like the rest of france, that there was no doubt of a favourable issue of the war, continued its purely scientific task. when the first defeats were announced, the habitual communications ceased, and the academy, unable to think of anything but the war, held sittings of three-quarters of an hour or even less.

one of the correspondents of the institute, the surgeon sédillot, who was in alsace at the head of an ambulance corps, and who himself performed as many as fifteen amputations in{187} one day, addressed two noteworthy letters to the president of the academy. those letters mark a date in the history of surgery, and show how restricted was then in france the share of some of pasteur’s ideas at the very time when in other countries they were adopted and followed. lister, the celebrated english surgeon, having, he said, meditated on pasteur’s theory of germs, and proclaimed himself his follower, convinced that complications and infection of wounds were caused by their giving access to living organisms and infectious germs, elements of trouble, often of death, had already in 1867 inaugurated a method of treatment. he attempted the destruction of germs floating in air by means of a vaporizer filled with a carbolic solution, then isolated and preserved the wound from the contact of the air. sponges, drainage tubes, etc., were subjected to minute precautions; in one word, he created antisepsis. four months before the war he had propounded the principles which should guide surgeons, but it occurred to no one in france, in the first battles, to apply the new method. “the horrible mortality amongst the wounded in battle,” writes sédillot, “calls for the attention of all the friends of science and humanity. the surgeon’s art, hesitating and disconcerted, pursues a doctrine whose rules seem to flee before research.... places where there are wounded are recognizable by the fetor of suppuration and gangrene.”

hundreds and thousands of wounded, their faces pale, but full of hope and desire to live, succumbed between the eighth and tenth day to gangrene and erysipelas. those failures of the surgery of the past are plain to us now that the doctrine of germs has explained everything; but, at that time, such an avowal of impotence before the mysterious contagium sui generis, which, the doctors averred, eluded all research, and such awful statistics of mortality embittered the anguish of defeat.

the academy then attempted to take a share in the national co-operation by making a special study of any subject which interested the public health and defence. a sitting on methods of steering balloons was succeeded by another on various means of preserving meat during the siege. then came an anxious inquiry into modes of alimentation of infants. at the end of october there were but 20,000 litres of milk per day to be procured in the whole of paris, and the healthy were implored to abstain from it. it was a question of life and death for young{188} children, and already many little coffins were daily to be seen on the road to the cemetery.

thus visions of death amongst soldiers in their prime and children in their infancy hung over the academy meeting hall. it was at one of those mournful sittings, on a dark autumn afternoon, that chevreul, an octogenarian member of the institute, who, like pasteur, had believed in civilization and in the binding together of nations through science, art and letters, looking at the sacks of earth piled outside the windows to save the library from the bursting shells, exclaimed in loud desolate tones—

“and yet we are in the nineteenth century, and a few months ago the french did not even think of a war which has put their capital into a state of siege and traced around its walls a desert zone where he who sowed does not reap! and there are public universities where they teach the beautiful, the true, and the right.”

“might goes before right,” bismarck said. a german journalist invented another phrase which went the round of europe: “the psychological moment for bombardment.” on january 5, one of the first prussian shells sank into the garden of the ecole normale; another burst in the very ambulance of the ecole. bertin, the sub-director, rushed through the suffocating smoke and ascertained that none of the patients was hurt; he found the breech between two beds. the miserable patients dragged themselves downstairs to the lecture rooms on the ground floor, not a much safer refuge.

from the heights of chatillon the enemy’s batteries were bombarding all the left bank of the seine, the prussians, regardless of the white flags bearing the red cross of geneva, were aiming at the val-de-grace and the panthéon. “where is the germany of our dreams?” wrote paul de st. victor on january 9, “the germany of the poets? between her and france an abyss of hatred has opened, a rhine of blood and tears that no peace can ever bridge over.”

on that same date, chevreul read the following declaration to the academy of science—

the garden of medicinal plants, founded in paris

by an edict of king louis xiii,

dated january, 1826,

{189}converted into the museum of natural history

by a decree of the convention on june 10, 1793,

was bombarded,

under the reign of wilhelm i king of

prussia, count von bismarck, chancellor,

by the prussian army, during the night

of january 8-9, 1871.

it had until then been respected by all parties

and all powers, national or

foreign.

pasteur, on reading this protest, regretted more than ever that he had not been there to sign it. it then occurred to him that he too might give vent to the proud plaint of the vanquished from his little house at arbois. he remembered with a sudden bitterness the diploma he had received from the university of bonn. many years had passed since the time in the first empire when one of the 110 french departments had been that of rhine and moselle, with coblentz as its préfecture and bonn and zimmern as sous-préfectures. when, in 1815, prussia’s iron hand seized again those rhenish provinces which had become so french at heart, the prussian king and his ministers hit upon the highly politic idea of founding a university on the picturesque banks of the rhine, thus morally conquering the people after reducing them by force. that university had been a great success and had become most prosperous. the strasburg faculty under the second empire, with its few professors and its general penury, seemed very poor compared to the bonn university, with its fifty-three professors and its vast laboratories of chemistry, physics and medicine, and even a museum of antiquities. pasteur and duruy had often exchanged remarks on that subject. but that rivalry between the two faculties was of a noble nature, animated as it was by the great feeling that science is superior to national distinctions. king wilhelm had once said, “prussia’s conquests must be of the moral kind,” and pasteur had not thought of any other conquests.

when in 1868 the university of bonn conferred upon him the diploma of doctor of medicine, saying that “by his very penetrating experiments, he had much contributed to the knowledge of the history of the generation of micro-organisms, and had happily advanced the progress of the science of fermentations,” he had been much pleased at this acknowledgment of{190} the future opened to medical studies by his work, and he was proud to show the degree he had received.

“now,” he wrote (january 18, 1871), to the head of the faculty of medicine, after recalling his former sentiments, “now the sight of that parchment is odious to me, and i feel offended at seeing my name, with the qualification of virum clarissimum that you have given it, placed under a name which is henceforth an object of execration to my country, that of rex gulielmus.

“while highly asseverating my profound respect for you, sir, and for the celebrated professors who have affixed their signatures to the decision of the members of your order, i am called upon by my conscience to ask you to efface my name from the archives of your faculty, and to take back that diploma, as a sign of the indignation inspired in a french scientist by the barbarity and hypocrisy of him who, in order to satisfy his criminal pride, persists in the massacre of two great nations.” pasteur’s protest ended with these words—

“written at arbois (jura) on january 18, 1871, after reading the mark of infamy inscribed on the forehead of your king by the illustrious director of the museum of natural history m. chevreul.”

“this letter will not have much weight with a people whose principles differ so totally from those that inspire us,” said pasteur, “but it will at least echo the indignation of french scientists.”

he made a collection of stories, of episodes, and letters, which fell in his way; amongst other things we find an open letter from general chanzy to the commandant of the prussian troops at vend?me, denouncing the insults, outrages, and inexcusable violence of the prussians towards the inhabitants of st. calais, who had shown great kindness to the enemy’s sick and wounded.

“you respond by insolence, destruction and pillage to the generosity with which we treat your prisoners and wounded. i indignantly protest, in the name of humanity and of the rights of men, which you trample under foot.”

pasteur also gathered up tales of bravery, of heroism, and of resignation—that form of heroism so often illustrated by women—during the terrible siege of paris. and, from all those things, arose the psychology of war in its two aspects: in the invading army a spirit of conquest carried to oppression, and even apart{191} from the thrilling moments of battle, giving to hatred and cruelty a cold-blooded sanction of discipline; in the vanquished nation, an irrepressible revolt, an intoxication of sacrifice. those who have not seen war do not know what love of the mother country means.

france was the more loved that she was more oppressed; she inspired her true sons with an infinite tenderness. sully-prudhomme, the poet of pensive youth, renouncing his love for humanity in general, promised himself that he would henceforth devote his life to the exclusive love of france. a greater poet than he, victor hugo, wrote at that time the first part of his année terrible, with its mingled devotion and despair.

the death of henri regnault was one of the sad episodes of the war. this brilliant young painter—he was only twenty-seven years of age—enlisted as a garde nationale, though exempt by law from any military service through being a laureate of the prix de rome.[30] he did his duty valiantly, and on january 19, at the last sortie attempted by the parisians, at buzenval, the last prussian shot struck him in the forehead. the académie des sciences, at its sitting of january 23, rendered homage to him whose coffin enclosed such dazzling prospects and some of the glory of france. the very heart of paris was touched, and a great sadness was felt at the funeral procession of the great artist who seemed an ideal type of all the youth and talent so heroically sacrificed—and all in vain—for the surrender of paris had just been officially announced.

regnault’s father, the celebrated physicist, a member of the institute, was at geneva when he received this terrible blow. another grief—not however comparable to the despair of a bereaved parent—befell him—an instance of the odious side of war, not in its horrors, its pools of blood and burnt dwellings, but in its premeditated cruelty. regnault had left his laboratory utensils in his rooms at the sèvres porcelain manufactory, of which he was the manager. everything was apparently left in the same place, not a window was broken, no locks forced; but a prussian, evidently an expert, had been there. “nothing seemed changed,” writes j. b. dumas, “in that abode of science, and yet everything was destroyed; the glass tubes of barometers, thermometers, etc., were broken; scales{192} and other similar instruments had been carefully knocked out of shape with a hammer.” in a corner was a heap of ashes; they were the registers, notes, manuscripts, all regnault’s work of the last ten years. “such cruelty,” exclaimed j. b. dumas, “is unexampled in history. the roman soldier who butchered archimedes in the heat of the onslaught may be excused—he did not know him; but with what sacrilegious meanness could such a work of destruction as this be accomplished!!!”

on the very day when the académie des sciences was condoling with henri regnault’s sorrowing father, pasteur, anxious at having had no news of his son, who had been fighting before héricourt, determined to go and look for him in the ranks of the eastern army corps. by poligny and lons-le-saulnier, the roads were full of stragglers from the various regiments left several days behind, their route completely lost, who begged for bread as they marched, barely covered by the tattered remnants of their uniforms. the main body of the army was on the way to besan?on, a sad procession of french soldiers, hanging their heads under the cold grey sky and tramping painfully in the snow.

bourbaki, the general-in-chief, a hero of african battlefields, was becoming more and more unnerved by the combinations of this war. whilst the minister, in a dispatch from bordeaux, had ordered him to move back towards d?le, to prevent the taking of dijon, then to hurry to nevers or joigny, where 20,000 men would be ready to be incorporated, bourbaki, overwhelmed by the lamentable spectacle under his eyes, could see no resource for his corps but a last line of retreat, pontarlier.

it was among that stream of soldiers that pasteur attempted to find his son. his old friend and neighbour, jules vercel, saw him start, accompanied by his wife and daughter, on tuesday, january 24, in a half broken down old carriage, the last that was left in the town. after journeying for some hours in the snow, the sad travellers spent the night in a little wayside inn near montrond; the old carriage with its freight of travelling boxes stood on the roadside like a gipsy’s caravan. the next morning they went on through a pine forest where the deep silence was unbroken save by the falling masses of snow from the spreading branches. they slept at censeau, the next day at chaffois, and it was only on the friday that they reached pontarlier, by roads made almost impracticable by the snow, the carriage now a mere wreck.{193}

the town was full of soldiers, some crouching round fires in the street, others stepping across their dead horses and begging for a little straw to lie on. many had taken refuge in the church and were lying on the steps of the altar; a few were attempting to bandage their frozen feet, threatened with gangrene.

suddenly the news spread that the general-in-chief, bourbaki, had shot himself through the brain. this did not excite much surprise. he had telegraphed two days before to the minister of war: “you cannot have an idea of the sufferings that the army has endured since the beginning of december. it is martyrdom to be in command at such a time,” he added despairingly.

“the retreat from moscow cannot have been worse than this,” said pasteur to a staff officer, commandant bourboulon, a nephew of sainte claire deville, whom he met in the midst of those horrors and who could give him no information as to his son’s battalion of chasseurs. “all that i can tell you,” said a soldier anxiously questioned by mme. pasteur, “is that out of the 1,200 men of that battalion there are but 300 left.” as she was questioning another, a soldier who was passing stopped: “sergeant pasteur? yes, he is alive; i slept by him last night at chaffois. he has remained behind; he is ill. you might meet him on the road towards chaffois.”

the pasteurs started again on the road followed the day before. they had barely passed the pontarlier gate when a rough cart came by. a soldier muffled in his great coat, his hands resting on the edge of the cart, started with surprise. he hurried down, and the family embraced without a word, so great was their emotion.

the capitulation of starving paris and the proposed armistice are historical events still present in the memory of men who were then beginning to learn the meaning of defeat. the armistice, which jules favre thought would be applied without restriction to all the army corps, was interpreted by bismarck in a peculiar way. he and jules favre between them had drawn up a protocol in general terms; it had been understood in those preliminary confabulations that, before drawing up the limits of the neutral zone applicable to the eastern army corps, some missing information would be awaited, the respective positions of the belligerents being unknown. the information did not come, and jules favre in his imprudent{194} trustfulness supposed that the delimitation would be done on the spot by the officers in command. when he heard that the prussian troops were continuing their march eastwards, he complained to bismarck, who answered that “the incident cannot have compromised the eastern army corps, as it already was completely routed when the armistice was signed.” this calculated reserve on bismarck’s part was eminently characteristic of his moral physiognomy, and this encounter between the two ministers proved once again the inferiority—when great interests are at stake—of emotional men to hard-hearted business men; however it must be acknowledged that bismarck’s statement was founded on fact. the eastern corps could have fought no more; its way was blocked. without food, without clothes, in many cases without arms, nothing remained to the unfortunate soldiers but the refuge offered by switzerland.

pasteur went to geneva with his son, who, after recovering from the illness caused by fatigue and privation, succeeded in getting back to france to rejoin his regiment in the early days of february. pasteur then went on to lyons and stayed there with his brother-in-law, m. loir, dean of the lyons faculty of science. he intended to go back to paris, but a letter from bertin dated february 18 advised him to wait. “this is the present state of the ecole: south wing: pulled down; will be built up again; workmen expected. third year dormitory: ambulance occupied by eight students. science dormitory and drawing classroom: ambulance again, forty patients. ground floor classroom: 120 artillery-men. pasteur laboratory: 210 gardes nationaux, refugees from issy. you had better wait.” bertin added, with his indomitable good humour, speaking of the bombardment: “the first day i did not go out, but i took my bearings and found the formula: in leaving the school, walk close along the houses on my left; on coming back, keep close to them on my right; with that i went out as usual. the population of paris has shown magnificent resignation and patience.... in order to have our revenge, everything will have to be rebuilt from the top to the bottom, the top especially.”

pasteur also thought that reforms should begin from the top. he prepared a paper dated from lyons, and entitled “why france found no superior men in the hours of peril.” amongst the mistakes committed, one in particular had been before his mind for twenty years, ever since he left the ecole normale:{195} “the forgetfulness, disdain even, that france had had for great intellectual men, especially in the realm of exact science.” this seemed the more sad to him that things had been very different at the end of the eighteenth century. pasteur enumerated the services rendered by science to his threatened country. if in 1792 france was able to face danger on all sides, it was because lavoisier, fourcroy, guyton de morveau, chaptal, berthollet, etc., discovered new means of extracting saltpetre and manufacturing gunpowder; because monge found a method of founding cannon with great rapidity; and because the chemist clouet invented a quick system of manufacturing steel. science, in the service of patriotism, made a victorious army of a perturbed nation. if marat, with his slanderous and injurious insinuations, had not turned from their course the feelings of the mob, lavoisier never would have perished on the scaffold. the day after his execution, lagrange said: “one moment was enough for his head to fall, and 200 years may not suffice to produce such another.” monge and berthollet, also denounced by marat, nearly shared the same fate: “in a week’s time we shall be arrested, tried, condemned and executed,” said berthollet placidly to monge, who answered with equal composure, thinking only of the country’s defence, “all i know is that my gun factories are working admirably.”

bonaparte, from the first, made of science what he would have made of everything—a means of reigning. when he started for egypt, he desired to have with him a staff of scientists, and monge and berthollet undertook to organize that distinguished company. later, when bonaparte became napoleon i, he showed, in the intervals between his wars, so much respect for the place due to science as to proclaim the effacement of national rivalry when scientific discoveries were in question. pasteur, when studying this side of the imperial character, found in some pages by arago on monge that, after waterloo, napoleon, in a conversation he had with monge at the elysée, said, “condemned now to command armies no longer, i can see but science with which to occupy my mind and my soul....”

alluding to the scientific supremacy of france during the early part of the nineteenth century, pasteur wrote: “all the other nations acknowledged our superiority, though each could take pride in some great men: berzelius in sweden, davy in england, volta in italy, other eminent men in ger{196}many and switzerland; but in no country were they as numerous as in france....” he added these regretful lines: “a victim of her political instability, france has done nothing to keep up, to propagate and to develop the progress of science in our country; she has merely obeyed a given impulse; she has lived on her past, thinking herself great by the scientific discoveries to which she owed her material prosperity, but not perceiving that she was imprudently allowing the sources of those discoveries to become dry, whilst neighbouring nations, stimulated by her past example, were diverting for their own benefit the course of those springs, rendering them fruitful by their works, their efforts and their sacrifices.

“whilst germany was multiplying her universities, establishing between them the most salutary emulation, bestowing honours and consideration on the masters and doctors, creating vast laboratories amply supplied with the most perfect instruments, france, enervated by revolutions, ever vainly seeking for the best form of government, was giving but careless attention to her establishments for higher education....

“the cultivation of science in its highest expression is perhaps even more necessary to the moral condition than to the material prosperity of a nation.

“great discoveries—the manifestations of thought in art, in science and in letters, in a word the disinterested exercise of the mind in every direction and the centres of instruction from which it radiates, introduce into the whole of society that philosophical or scientific spirit, that spirit of discernment, which submits everything to severe reasoning, condemns ignorance and scatters errors and prejudices. they raise the intellectual level and the moral sense, and through them the divine idea itself is spread abroad and intensified.”

at the very time when pasteur was preoccupied with the desire of directing the public mind towards the principles of truth, justice and sovereign harmony, sainte claire deville, speaking of the academy, expressed similar ideas, proclaiming that france had been vanquished by science and that it was now time to free scientific bodies from the tyranny of red tape. why should not the academy become the centre of all measures relating to science, independently of government offices or officials?

j. b. dumas took part in the discussion opened by sainte claire deville, and agreed with his suggestions. he might{197} have said more, however, on a subject which he often took up in private: the utility of pure science in daily experience. with his own special gift of generalization, he could have expounded the progress of all kinds due to the workers who, by their perseverance in resolving difficult problems, have brought about so many precious and unexpected results. few men in france realized at that time that laboratories could be the vestibule of farms, factories, etc.; it was indeed a noble task, that of proving that science was intended to lighten the burden of humanity, not merely to be applied to devastation, carnage, and hatred.

pasteur was in the midst of these philosophical reflections when he received the following answer from the principal of the faculty of medicine of bonn:

“sir, the undersigned, now principal of the faculty of medicine of bonn, is requested to answer the insult which you have dared to offer to the german nation in the sacred person of its august emperor, king wilhelm of prussia, by sending you the expression of its entire contempt.”—dr. maurice naumann.

“p.s.—desiring to keep its papers free from taint, the faculty herewith returns your screed.”

pasteur’s reply contained the following: “i have the honour of informing you, mr. principal, that there are times when the expression of contempt in a prussian mouth is equivalent for a true frenchman to that of virum clarissimum which you once publicly conferred upon me.”

after invoking in favour of alsace-lorraine, truth, of justice, and the laws of humanity, pasteur added in a postscript—

“and now, mr. principal, after reading over both your letter and mine, i sorrow in my heart to think that men who like yourself and myself have spent a lifetime in the pursuit of truth and progress, should address each other in such a fashion, founded on my part on such actions. this is but one of the results of the character your emperor has given to this war. you speak to me of taint. mr. principal, taint will rest, you may be assured, until far-distant ages, on the memory of those who began the bombardment of paris when capitulation by famine was inevitable, and who continued this act of savagery after it had become evident to all men that it would not advance by one hour the surrender of the heroic city.{198}”

whilst pasteur thus felt those simple and strong impressions as a soldier or the man in the street might do, the creative power of his nature was urging him to great and useful achievements. he wrote from lyons in march to m. duclaux—

“my head is full of splendid projects; the war sent my brain to grass, but i now feel ready for further work. perhaps i am deluding myself; anyhow i will try.... oh! why am i not rich, a millionaire? i would say to you, to raulin, to gernez, to van tieghem, etc., come, we will transform the world by our discoveries. how fortunate you are to be young and strong! why can i not begin a new life of study and work! unhappy france, beloved country, if i could only assist in raising thee from thy disasters!”

a few days later, in a letter to raulin, this desire for devoted work was again expressed almost feverishly. he could foresee, in the dim distance, secret affinities between apparently dissimilar things. he had at that time returned to the researches which had absorbed his youth (because those studies were less materially difficult to organize), and he could perceive laws and connections between the facts he had observed and those of the existence of which he felt assured.

“i have begun here some experiments in crystallization which will open a great prospect if they should lead to positive results. you know that i believe that there is a cosmic dissymmetric influence which presides constantly and naturally over the molecular organization of principles immediately essential to life; and that, in consequence of this, the species of the three kingdoms, by their structure, by their form, by the disposition of their tissues, have a definite relation to the movements of the universe. for many of those species, if not for all, the sun is the primum movens of nutrition; but i believe in another influence which would affect the whole organization, for it would be the cause of the molecular dissymmetry proper to the chemical components of life. i want to be able by experiment to grasp a few indications as to the nature of this great cosmic dissymmetrical influence. it must, it may be electricity, magnetism.... and, as one should always proceed from the simple to the complex, i am now trying to crystallize double racemate of soda and ammonia under the influence of a spiral solenoid.

“i have various other forms of experiment to attempt. if one of them should succeed, we shall have work for the rest of{199} our lives, and in one of the greatest subjects man could approach, for i should not despair of arriving by this means at a very deep, unexpected and extraordinary modification of the animal and vegetable species.

“good-bye, my dear raulin. let us endeavour to distract our thoughts from human turpitudes by the disinterested search after truth.”

in a little notebook where he jotted down some intended experiments we find evidence of those glimpses of divination in a few summary lines: “show that life is in the germ, that it has been but in a state of transmission since the origin of creation. that the germ possesses possibilities of development, either of intelligence and will, or—and in the same way—of physical organs. compare these possibilities with those possessed by the germ of chemical species which is in the chemical molecule. the possibilities of development in the germ of the chemical molecule consist in crystallization, in its form, in its physical and chemical properties. those properties are in power in the germ of the molecule in the same way as the organs and tissues of animals and plants are in their respective germs. add: nothing is more curious than to carry the comparison of living species with mineral species into the study of the wounds of either, and of their healing by means of nutrition—a nutrition coming from within in living beings, and from without through the medium of crystallization in the others. here detail facts....”

in that same notebook, pasteur, after writing down the following heading, “letter to prepare on the species in connection with molecular dissymmetry,” added, “i could write that letter to bernard. i should say that being deprived of a laboratory by the present state of france, i am going to give him the preconceived ideas that i shall try to experiment upon when better times come. there is no peril in expressing ideas a priori, when they are taken as such, and can be gradually modified, perhaps even completely transformed, according to the result of the observation of facts.”

he once compared those preconceived ideas with searchlights guiding the experimentalist, saying that they only became dangerous when they became fixed ideas.

civil war had now come, showing, as renan said, “a sore under the sore, an abyss below the abyss.” what were the hopes and projects of pasteur and of sainte claire deville now{200} that the very existence of the divided country was jeopardized under the eyes of the prussians? the world of letters and of science, helpless amidst such disorders, had dispersed; saint claire deville was at gex, dumas at geneva. some were wondering whether lectures could not be organized in switzerland and in belgium as they had been under the empire, thus spreading abroad the influence of french thought. examples might be quoted of men who had served the glory of their country in other lands, such as descartes, who took refuge in holland in order to continue his philosophic meditations. pasteur might have been tempted to do likewise. already, before the end of the war, an italian professor of chemistry, signor chiozza, who had applied pasteur’s methods to silkworms in the neighbourhood of villa vicentina, got the italian government to offer him a laboratory and the direction of a silkworm establishment. pasteur refused, and a deputy of pisa, signor toscanelli, hearing of this, obtained for pasteur the offer of what was better still—a professor’s chair of chemistry applied to agriculture at pisa; this would give every facility for work and all laboratory resources. “pisa,” signor chiozza said, “is a quiet town, a sort of latin quarter in the middle of the country, where professors and students form the greater part of the population. i think you would be received with the greatest cordiality and quite exceptional consideration ... i fear that black days of prolonged agitation are in store for france.”

pasteur’s health and work were indeed valuable to the whole world, and signor chiozza’s proposition seemed simple and rational. pasteur was much divided in his mind: his first impulse was to renew his refusal. he thought but of his vanquished country, and did not wish to forsake it. but was it to his country’s real interests that he should remain a helpless spectator of so many disasters? was it not better to carry french teaching abroad, to try and provoke in young italian students enthusiasm for french scientists, french achievements? he might still serve his beloved country in that quiet retreat, amidst all those facilities for continuous work. he thought of writing to raulin, who had relations in italy, and who might follow his master. finally, he was offered very great personal advantages, a high salary—and this determined his refusal, for, as he wrote to signor chiozza, “i should feel that i deserved a deserter’s penalty if i sought, away from my{201} country in distress, a material situation better than it can offer me.”

“nevertheless allow me to tell you, sir (he wrote to signor toscanelli, refusing his offer), in all sincerity, that the memory of your offer will remain in the annals of my family as a title of nobility, as a proof of italy’s sympathy for france, as a token of the esteem accorded to my work. and as far as you, m. le député, are concerned it will remain in my eyes a brilliant proof of the way in which public men in italy regard science and its grandeur.”

and now what was pasteur to do—he who could not live away from a laboratory? in april, 1871, he could neither go back to paris and the commune nor to arbois, now transformed into a prussian dép?t. it seemed, indeed, from the letters he received that his fellow citizens were now destined but to feed and serve a victorious foe, whose exactions were all the more rigorous that the invasion of the town on january 25 had been preceded by an attempt at resistance on the part of the inhabitants. on that morning, a few french soldiers who were seeking their regiments and a handful of franc tireurs had posted themselves among the vines. about ten o’clock a first shot sounded in the distance; in a turn of the sinuous besan?on road, when the prussian vanguard had appeared, a zouave—who the day before was begging from door to door, shaking with ague, and who had taken refuge in the village of montigny, two kilometres from arbois—had in despair fired his last cartridge. a squad of prussians left the road and rushed towards the smoke of the gun. the soldier was seized, shot down on the spot, and mutilated with bayonets. whilst the main column continued their advance towards the town, detachments explored the vines on either side of the road, shooting here and there. an old man who, with a courageous indifference, was working in his vineyard was shot down at his work. a little pastrycook’s boy, nicknamed biscuit by the arboisians, who, led by curiosity; had come down from the upper town to the big poplar trees at the entrance of arbois, suddenly staggered, struck by a prussian bullet. he was just able to creep back to the first house, his eyes already dimmed by death.

those were but the chances of war, but other crueller episodes thrilled pasteur to the very depths of his soul. such things are lost in history, just as a little blood spilt disappears{202} in a river, but, for the witnesses and contemporaries of the facts, the trace of blood remains. an incident will help the reader to understand the lasting indignation the war excited in pasteur.

one of the prussian sergeants, who, after the shot fired at montigny, were leading small detachments of soldiers, thought that a house on the outskirts of arbois, in the faubourg of verreux, looked as if it might shelter franc tireurs. he directed his men towards it and the house was soon reached.

it was now twelve o’clock, all fighting had ceased, and the first prussians who had arrived were masters of the town. others were arriving from various directions; a heavy silence reigned over the town. the mayor, m. lefort, led by a prussian officer who covered him with a revolver whenever he addressed him, was treated as a hostage responsible for absolute submission. every door in the small town hall was opened in succession in order to see that there were no arms hidden. the mayor was each time made to pass first, so that he should receive the shot in case of a surprise. in the library, three flags, which general delort had brought back from the rhine campaign when he was a captain in the cavalry and given to his native town, were torn down and the general’s bust overturned.

the sergeant, violently entering the suspected house with his men, found a whole family peacefully sitting down to their dinner—the husband, wife, a son of nineteen, and two young daughters. the invaders made no search nor asked any questions of those poor people, who had probably done nothing worse than to offer a few glasses of wine to french soldiers as they passed. the sergeant did not even ask the name of the master of the house (antoine ducret, aged fifty-nine), but seized him by his coat and ordered his men to seize the son too. the woman, who rushed to the door in her endeavour to prevent her husband and her son from being thus taken from her, was violently flung to the end of the room, her trembling daughters crouching around her as they listened to the heavy prussian boots going down the wooden stairs. there is a public drinking fountain not far from the house; ducret was taken there and placed against a wall. he understood, and cried out, “spare my son!!” “what do you say?” said the sergeant to the boy. “i will stay with my father,” he answered simply. the father, struck by two bullets at close range, fell at the feet of{203} his son, who was shot down immediately afterwards. the two corpses, afterwards mutilated with bayonets, remained lying by the water side; the neighbours succeeded in preventing the mother and her two daughters from leaving their house until the bodies had been placed in a coffin. on the tombs of antoine and charles ducret the equivocal inscription was placed “fell at arbois, january 25, 1871, under prussian fire.” for the honour of humanity, a german officer, having heard these details, offered the life of the sergeant to ducret’s widow; but she entertained no thoughts of revenge. “his death would not give them back to me,” she said.

pasteur could not become resigned to the humiliation of france, and, tearing his thoughts from the nightmare of the war and the commune, he dwelt continually on the efforts that would be necessary to carry out the great task of raising the country once again to its proper rank. in his mind it was the duty of every one to say, “in what way can i be useful?” each man should strive not so much to play a great part as to give the best of his ability. he had no patience with those who doubt everything in order to have an excuse for doing nothing.

he had indeed known dark moments of doubt and misgivings, as even the greatest minds must do, but notwithstanding these periods of discouragement he was convinced that science and peace will ultimately triumph over ignorance and war. in spite of recent events, the bitter conditions of peace which tore unwilling alsace and part of lorraine away from france, the heavy tax of gold and of blood weighing down future generations, the sad visions of young men in their prime cut down on the battlefield or breathing their last in hospitals all to no apparent purpose; in spite of all these sad memories he was persuaded that thinkers would gradually awaken in the nations ideas of justice and of concord.

he had now for nine years been following with a passionate interest some work begun in his own laboratory by raulin, his first curator. some of the letters he wrote to raulin during those nine years give us a faint idea of the master that pasteur was. it had been with great regret that raulin had left the laboratory in obedience to the then laws of the university in order to take up active work at the brest college, and pasteur’s letters (december, 1862) brought him joy and encouragement: “keep up your courage, do not allow the idleness of pro{204}vincial life to disturb you. teach your pupils to the very best of your ability and give up your leisure to experiments; this was m. biot’s advice to myself.” when in july, 1863, he began to fear that raulin might allow imagination to lead him astray in his work, he repeatedly advised him to state nothing that could not be proved: “be very strict in your deductions”; then, apparently, loth to damp the young man’s ardour: “i have the greatest confidence in your judgment; do not take too much heed of my observations.”

in 1863 pasteur asked raulin to come with him, gernez and duclaux, to arbois for some studies on wines, etc., but raulin, absorbed in the investigations he had undertaken, refused; in 1865 he refused to come to alais, still being completely wrapt up in the same work. pasteur sympathized heartily with his pupil’s perseverance, and, when raulin was at last able to announce to his master the results so long sought after, pasteur hurried to caen, where raulin was now professor of physics, and returned full of enthusiasm. his modesty in all that concerned himself now giving way to delighted pride, he spoke of raulin’s discoveries to every one. yet they concerned an apparently unimportant subject—a microscopical fungus, a simple mucor, whose spores, mingled with atmospheric germs, develop on bread moistened with vinegar or on a slice of lemon; yet no precious plant ever inspired more care or solicitude than that aspergillus niger, as it is called. raulin, inspired by pasteur’s studies on cultures in an artificial medium, that is, a medium exclusively composed of defined chemical substances, resolved to find for this plant a typical medium capable of giving its maximum development to the aspergillus niger. some of his comrades looked upon this as upon a sort of laboratory amusement; but raulin, ever a man of one idea, looked upon the culture of microscopic vegetation as a step towards a greater knowledge of vegetable physiology, leading to the development of artificial manure production, and from that to the rational nutrition of the human organisms. he started from the conditions indicated by pasteur for the development of mucedin? in general and in particular for a mucor which has some points of resemblance with the aspergillus niger, the penicillium glaucum, which spreads a bluish tint over mouldy bread, jam, and soft cheeses. raulin began by placing pure spores of aspergillus niger on the surface of a saucer containing everything{205} that seemed necessary to their perfect growth, in a stove heated to a temperature of 20°c.; but in spite of every care, after forty days had passed, the tiny fungus was languishing and unhealthy. a temperature of 30° did not seem more successful; and when the stove was heated to above 38° the result was the same. at 35°, with a moist and changing atmosphere, the result was favourable—very fortunately for raulin, for the principal of the college, an economically minded man, did not approve of burning so much gas for such a tiny fungus and with such poor results. this want of sympathy excited raulin’s solemn wrath and caused him to meditate dark projects of revenge, such as ignoring his enemy in the street on some future occasion. in the meanwhile he continued his slow and careful experiments. he succeeded at last in composing a liquid, technically called raulin’s liquid, in which the aspergillus niger grew and flourished within six or even three days. eleven substances were necessary: water, candied sugar, tartaric acid, nitrate of ammonia, phosphate of ammonia, carbonate of potash, carbonate of magnesia, sulphate of ammonia, sulphate of zinc, sulphate of iron, and silicate of potash. he now studied the part played by each of those elements, varying his quantities, taking away one substance and adding another, and obtained some very curious results. for instance, the aspergillus was extraordinarily sensitive to the action of zinc; if the quantity of zinc was reduced by a few milligrams the vegetation decreased by one-tenth. other elements were pernicious; if raulin added to his liquid 1/1600000 of nitrate of silver, the growth of the fungus ceased. moreover, if he placed the liquid in a silver goblet instead of a china saucer, the vegetation did not even begin, “though,” writes m. duclaux, analysing this fine work of his fellow student, “it is almost impossible to chemically detect any dissolution of the silver into the liquid. but the fungus proves it by dying.”

in this thesis, now a classic, which only appeared in 1870, raulin enumerated with joyful gratitude all that he owed to his illustrious master—general views, principles and methods, suggestive ideas, advice and encouragement—saying that pasteur had shown him the road on which he had travelled so far. pasteur, touched by his pupil’s affection, wrote to thank him, saying: “you credit me with too much; it is enough for me that your work should be known as having been begun in my{206} laboratory, and in a direction the fruitfulness of which i was perhaps the first to point out. i had only conceived hopes, and you bring us solid realities.”

in april, 1871, pasteur, preoccupied with the future, and ambitious for those who might come after him, wrote to claude bernard: “allow me to submit to you an idea which has occurred to me, that of conferring on my dear pupil and friend raulin the experimental physiology prize, for his splendid work on the nutriment of mucors, or rather of a mucor, the excellence of which work has not escaped you. i doubt if you can find anything better. i must tell you that this idea occurred to me whilst reading your admirable report on the progress of general physiology in france. if therefore my suggestion seems to you acceptable, you will have sown the germ of it in my mind; if you disapprove of it i shall make you partly responsible.”

claude bernard hastened to reply: “you may depend upon my support for your pupil m. raulin. it will be for me both a pleasure and a duty to support such excellent work and to glorify the method of the master who inspired it.”

in his letter to claude bernard, pasteur had added these words: “i have made up my mind to go and spend a few months at royat with my family, so as to be near my dear duclaux. we shall raise a few grammes of silkworm seed.”

m. duclaux was then professor of chemistry at the faculty of clermont ferrand, a short distance from royat, and pasteur intended to walk every day to the laboratory of his former pupil. but m. duclaux did not countenance this plan; he meant to entertain his master and his master’s family in his own house, 25, rue montlosier, where he could even have one room arranged as a silkworm nursery. he succeeded in persuading pasteur, and they organized a delightful home life which recalled the days at pont gisquet before the war.

pasteur was seeking the means of making his seed-selecting process applicable to small private nurseries as well as to large industrial establishments. the only difficulty was the cost of the indispensable microscope; but pasteur thought that each village might possess its microscope, and that the village schoolmaster might be entrusted with the examination of the moths.

in a letter written in april, 1871, to m. bellotti, of the milan civic museum, pasteur, after describing in a few lines the simple process he had taken five years to study, added{207}—

“if i dared to quote myself, i would recall those words from my book—

“‘if i were a silkworm cultivator i never would raise seed from worms i had not observed during the last days of their life, so as to satisfy myself as to their vigour and agility just before spinning. the seed chosen should be that which comes from worms who climbed the twigs with agility, who showed no mortality from flachery between the fourth moulting and climbing time, and whose freedom from corpuscles will have been demonstrated by the microscope. if that is done, any one with the slightest knowledge of silkworm culture will succeed in every case.’”

italy and austria vied with each other in adopting the seed selected by the pasteur system. but it was only when pasteur was on the eve of receiving from the austrian government the great prize offered in 1868 to “whoever should discover a preventive and curative remedy against pébrine” that french sericicultors began to be convinced. the french character offers this strange contrast, that france is often willing to risk her fortune and her blood for causes which may be unworthy, whilst at another moment, in everyday life, she shrinks at the least innovation before accepting a benefit originated on her own soil. the french often wait until other nations have adopted and approved a french discovery before venturing to adopt it in their turn.

pasteur did not stop to look back and delight in his success, but hastened to turn his mind to another kind of study. his choice of a subject was influenced by patriotic motives. germany was incontestably superior to france in the manufacture of beer, and he conceived the thought of making france a successful rival in that respect; in order to enable himself to do so, he undertook to study the scientific mechanism of beer manufacture.

there was a brewery at chamalières, between clermont and royat. pasteur began by visiting it with eager curiosity, inquiring into the minutest details, endeavouring to find out the why and the wherefore of every process, and receiving vague answers with much astonishment. m. kuhn, the chamalières brewer, did not know much more about beer than did his fellow brewers in general. very little was known at that time about the way it was produced; when brewers received complaints from their customers, they procured yeast{208} from a fresh source. in a book of reference which was then much in use, entitled alimentary substances: the means of improving and preserving them, and of recognizing their alterations, six pages were given up to beer by the author, m. payen, a member of the institute. he merely showed that germinated barley, called malt, was diluted, then heated and mixed with hops, thus forming beer-wort, which was submitted, when cold, to alcoholic fermentation through the yeast added to the above liquid. m. payen conceded to beer some nutritive properties, but added, a little disdainfully, “beer, perhaps on account of the pungent smell of hops, does not seem endowed with stimulating properties as agreeable, or as likely to inspire such bright and cheerful ideas, as the sweet and varied aroma of the good wines of france.”

in a paragraph on the alterations of beer—“spontaneous alterations”—m. payen said that it was chiefly during the summer that beer became altered. “it becomes acid, and even noticeably putrid, and ceases to be fit to drink.”

pasteur’s hopes of making french beer capable of competing with german beer were much strengthened by faith in his own method. he had, by experimental proof, destroyed the theory of spontaneous generation; he had shown that chance has no share in fermentations; the animated nature and the specific characteristics of those ferments, the methods of culture in appropriate media, were so many scientific points gained. the difficulties which remained to be solved were the question of pure yeast and the search for the causes of alteration which make beer thick, acid, sour, slimy or putrid. pasteur thought that these alterations were probably due to the development of germs in the air, in the water, or on the surface of the numerous utensils used in a brewery.

as he advanced further and further into that domain of the infinitely small which he had discovered, whether the subject was wine, vinegar, or silkworms—this last study already opening before him glimpses of light on human pathology—new and unexpected visions rose before his sight.

pasteur had formerly demonstrated that if a putrescible liquid, such as beef broth for instance, after being previously boiled, is kept in a vessel with a long curved neck, the air only reaching it after having deposited its germs in the curves of the neck, does not alter it in any way. he now desired to invent an apparatus which would protect the wort against external{209} dusts, against the microscopic germs ever ready to interfere with the course of proper fermentation by the introduction of other noxious ferments. it was necessary to prove that beer remains unalterable whenever it does not contain the organisms which cause its diseases. many technical difficulties were in the way, but the brewers of chamalières tried in the most obliging manner to facilitate things for him.

this exchange of services between science and industry was in accordance with pasteur’s plan; though he had been prophesying for fourteen years the great progress which would result from an alliance between laboratories and factories, the idea was hardly understood at that time. yet the manufacturers of lille and orleans, the wine merchants and the silkworm cultivators of the south of france, and of austria and italy, might well have been called as enthusiastic witnesses to the advantages of such a collaboration.

pasteur, happy to make the fortune of others, intended to organize, against the danger of alterations in beer, some experiments which would give to that industry solid notions resting on a scientific basis. “dear master,” wrote he to j. b. dumas on august 4, 1871, from clermont, “i have asked the brewer to send you twelve bottles of my beer.... i hope you will find it compares favourably even with the excellent beer of paris cafés.” there was a postscript to this letter, proving once more pasteur’s solicitude for his pupils. “a thousand thanks for your kind welcome of raulin’s work; bernard’s support has also been promised him. the academy could not find a better recipient for the prize. it is quite exceptional work.”

pasteur, ever full of praises for his pupil, also found excuses for him. in spite of m. duclaux’s pressing request, raulin had again found reasons to refuse an invitation to come to auvergne for a few days. “i regret very much that you did not come to see us,” wrote pasteur to raulin, “especially on account of the beer.... tell me what you think of doing. when are you coming to paris for good? i shall want you to help me to arrange my laboratory, where everything, as you know, has still to be done; it must be put into working order as soon as possible.”

pasteur would have liked raulin to come with him to london in september, 1871, before settling down in paris.

the chamalières brewery was no longer sufficient for pasteur; he wished to see one of those great english breweries{210} which produce in one year more than 100,000 hectolitres of beer. the great french savant was most courteously received by the managers of one of the most important breweries in london, who offered to show him round the works where 250 men were employed. but pasteur asked for a little of the barm of the porter which was flowing into a trough from the cask. he examined that yeast with a microscope, and soon recognized a noxious ferment which he drew on a piece of paper and showed to the bystanders, saying, “this porter must leave much to be desired,” to the astonished managers, who had not expected this sudden criticism. pasteur added that surely the defect must have been betrayed by a bad taste, perhaps already complained of by some customers. thereupon the managers owned that that very morning some fresh yeast had had to be procured from another brewery. pasteur asked to see the new yeast, and found it incomparably purer, but such was not the case with the barm of the other products then in fermentation—ale and pale ale.

by degrees, samples of every kind of beer on the premises were brought to pasteur and put under the microscope. he detected marked beginnings of disease in some, in others merely a trace, but a threatening one. the various foremen were sent for; this scientific visit seemed like a police inquiry. the owner of the brewery, who had been fetched, was obliged to register, one after another, these experimental demonstrations. it was only human to show a little surprise, perhaps a little impatience of wounded feeling. but it was impossible to mistake the authority of the french scientist’s words: “every marked alteration in the quality of the beer coincides with the development of micro-organisms foreign to the nature of true beer yeast.” it would have been interesting to a psychologist to study in the expression of pasteur’s hearers those shades of curiosity, doubt, and approbation, which ended in the thoroughly english conclusion that there was profit to be made out of this object lesson.

pasteur afterwards remembered with a smile the answers he received, rather vague at first, then clearer, and, finally—interest and confidence now obtained—the confession that there was in a corner of the brewery a quantity of spoilt beer, which had gone wrong only a fortnight after it was made, and was not drinkable. “i examined it with a microscope,” said pasteur, “and could not at first detect any ferments of{211} disease; but guessing that it might have become clear through a long rest, the ferments now inert having dropped to the bottom of the reservoirs, i examined the deposit at the bottom of the reservoirs. it was entirely composed of filaments of disease unmixed with the least globule of alcoholic yeast. the complementary fermentation of that beer had therefore been exclusively a morbid fermentation.”

when he visited the same brewery again, a week later, he found that not only had a microscope been procured immediately, but the yeast of all the beer then being brewed had been changed.

pasteur was happy to offer to the english, who like to call themselves practical men, a proof of the usefulness of disinterested science, persuaded as he was that the moral debt incurred to a french scientist would in some measure revert to france herself. “we must make some friends for our beloved france,” he would say. and if in the course of conversation an englishman gave expression to any doubt concerning the future of the country, pasteur, his grave and powerful face full of energy, would answer that every frenchman, after the horrible storm which had raged for so many months, was valiantly returning to his daily task, whether great or humble, each one thinking of retrieving the national fall.

every morning, as he left his hotel to go to the various breweries which he was now privileged to visit in their smallest details, he observed this english people, knowing the value of time, seeing its own interests in all things, consistent in its ideas and in its efforts, respectful of established institutions and hierarchy; and he thought with regret how his own countrymen lacked these qualities. but if the french are rightly taxed with a feverish love of change, should not justice be rendered to that generous side of the french character, so gifted, capable of so much, and which finds in self-sacrifice the secret of energy, for whom hatred is a real suffering? “let us work!” pasteur’s favourite phrase ever ended those philosophical discussions.

he wanted to do two years’ work in one, regardless of health and strength. beyond the diseases of beer, avoidable since they come from outside, he foresaw the application of the doctrine of exterior germs to other diseases. but he did not allow his imagination to run away with him, and resolutely{212} fixed his mind on his present object, which was the application of science to the brewing industry.

“the interest of those visits to english breweries,” wrote pasteur to raulin, “and of the information i am able to collect (i hear that i ought to consider this as a great favour) causes me to regret very much that you should be in want of rest, for i am sure you would have been charmed to acquire so much instruction de visu. why should you not come for a day or two if your health permits? do as you like about that, but in any case prepare for immediate work on my return. we need not wait for the new laboratory; we can settle down in the old one and in a paris brewery.”

when pasteur returned to paris, bertin, who had not seen him since the recent historic events, welcomed him with a radiant delight. school friendships are like those favourite books which always open at the page we prefer; time has no hold on certain affections; ever new, ever young, they never show signs of age. bertin’s love was very precious to pasteur, though the two friends were as different from each other as possible. pasteur, ever preoccupied, seemed to justify the englishman who said that genius consists in an infinite capacity for taking pains; whilst bertin, with his merry eyes, was the very image of a smiling philosopher. in spite of his position as sub-director, which he most conscientiously filled, he was not afraid to whistle or to sing popular songs as he went along the passages of the ecole normale. he came round to pasteur’s rooms almost every evening, bringing with him joy, lightness of heart, and a rest and relaxation for the mind, brightening up his friend by his amusing way of looking at things in general, and—at that time—beer in particular.

whilst pasteur saw but pure yeast, and thought but of spores of disease, ferments, and parasitic invasions, bertin would dilate on certain cafés in the latin quarter, where, without regard to great scientific principles, experts could be asked to pronounce between the beer on the premises and laboratory beer, harmless and almost agreeable, but lacking in the refinement of taste of which bertin, who had spent many years in strasburg, was a competent judge. pasteur, accustomed to an absolutely infallible method, like that which he had invented for the seeding of silkworms, heard bertin say to him, “first of all, give me a good bock, you can talk learnedly afterwards.” pasteur acknowledged, however, the improve{213}ments obtained by certain brewers, who, thanks to the experience of years, knew how to choose yeast which gave a particular taste, and also how to employ preventive measures against accidental and pernicious ferments (such as the use of ice, or of hops in a larger quantity). but, though laughing at bertin’s jokes, pasteur was convinced that great progress in the brewer’s art would date from his studies.

he was now going through a series of experiments, buying at bertin’s much praised cafés samples of various famous beers—strasburg, nancy, vienna, burton’s, etc. after letting the samples rest for twenty-four hours he decanted them and sowed one drop of the deposit in vessels full of pure wort, which he placed in a temperature of 20° c. after fifteen or eighteen days he studied and tasted the yeasts formed in the wort, and found them all to contain ferments of diseases. he sowed some pure yeast in some other vessels, with the same precautions, and all the beers of this series remained pure from strange ferments and free from bad taste; they had merely become flat.

he was eagerly seeking the means of judging how his laboratory tests would work in practice. he spent some time at tantonville, in lorraine, visiting an immense brewery, of which the owners were the brothers tourtel. though very carefully kept, the brewery was yet not quite clean enough to satisfy him. it is true that he was more than difficult to please in that respect; a small detail of his everyday life revealed this constant preoccupation. he never used a plate or a glass without examining them minutely and wiping them carefully; no microscopic speck of dust escaped his short-sighted eyes. whether at home or with strangers he invariably went through this preliminary exercise, in spite of the anxious astonishment of his hostess, who usually feared that some negligence had occurred, until pasteur, noticing her slight dismay, assured her that this was but an inveterate scientist’s habit. if he carried such minute care into daily life, we can imagine how strict was his examination of scientific things and of brewery tanks.

after those studies at tantonville with his curator, m. grenet, pasteur laid down three great principles—

1. every alteration either of the wort or of the beer itself depends on the development of micro-organisms which are ferments of diseases.{214}

2. these germs of ferments are brought by the air, by the ingredients, or by the apparatus used in breweries.

3. whenever beer contains no living germs it is unalterable.

when once those principles were formulated and proved they were to triumph over all professional uncertainties. and in the same way that wines could be preserved from various causes of alteration by heating, bottled beer could escape the development of disease ferments by being brought to a temperature of 50° to 55°. the application of this process gave rise to the new word “pasteurized” beer, a neologism which soon became current in technical language.

pasteur foresaw the distant consequences of these studies, and wrote in his book on beer—

“when we see beer and wine subjected to deep alterations because they have given refuge to micro-organisms invisibly introduced and now swarming within them, it is impossible not to be pursued by the thought that similar facts may, must, take place in animals and in man. but if we are inclined to believe that it is so because we think it likely and possible, let us endeavour to remember, before we affirm it, that the greatest disorder of the mind is to allow the will to direct the belief.”

this shows us once more the strange duality of this inspired man, who associated in his person the faith of an apostle with the inquiring patience of a scientist.

he was often disturbed by tiresome discussions from the researches to which he would gladly have given his whole time. the heterogenists had not surrendered; they would not admit that alterable organic liquids could be indefinitely preserved from putrefaction and fermentation when in contact with air freed from dusts.

pouchet, the most celebrated of them, who considered that part of a scientist’s duty consists in vulgarizing his discoveries, was preparing for the new year, 1872, a book called the universe: the infinitely great and the infinitely small. he enthusiastically recalled the spectacle revealed at the end of the seventeenth century by the microscope, which he compared to a sixth sense. he praised the discoveries made in 1838 by ehrenberg on the prodigious activity of infusories, but he never mentioned pasteur’s name, leaving entirely on one side the immense work accomplished by the infinitely small and ever active agents of putrefaction and fermentation.{215} he owned that “a few microzoa did fly about here and there,” but he called the theory of germs a “ridiculous fiction.”

at the same time liebig, who, since the interview in july, 1870, had had time to recover his health, published a long treatise disputing certain facts put forward by pasteur.

pasteur had declared that, in the process of vinegar-making known as the german process, the chips of beech-wood placed in the barrels were but supports for the mycoderma aceti. liebig, after having, he said, consulted at munich the chief of one of the largest vinegar factories, who did not believe in the presence of the mycoderma, affirmed that he himself had not seen a trace of the fungus on chips which had been used in that factory for twenty-five years.

in order to bring this debate to a conclusion pasteur suggested a very simple experiment, which was to dry some of those chips rapidly in a stove and to send them to paris, where a commission, selected from the members of the académie des sciences, would decide on this conflict. pasteur undertook to demonstrate to the commission the presence of the mycoderma on the surface of the chips. or another means might be used: the munich vinegar maker would be asked to scald one of his barrels with boiling water and then to make use of it again. “according to liebig’s theory,” said pasteur, “that barrel should work as before, but i affirm that no vinegar will form in it for a long time, not until new mycoderma have grown on the surface of the chips.” in effect, the boiling water would destroy the little fungus. with the usual clear directness which increased the interest of the public in this scientific discussion, pasteur formulated once more his complete theory of acetification: “the principle is very simple: whenever wine is transformed into vinegar, it is by the action of the layer of mycoderma aceti developed on its surface.” liebig, however, refused the suggested test.

immediately after that episode a fresh adversary, m. frémy, a member of the académie des sciences, began with pasteur a discussion, which was destined to be a long one, on the question of the origin of ferments. m. frémy alluded to the fact that he had given many years to that subject, having published a notice on lactic fermentation as far back as 1841, “at a time,” he said, “when our learned colleague—m. pasteur—was barely entering into science.”... “in the production of wine,” said m. frémy, “it is the juice of the fruit{216} itself, which, put in contact with air, gives birth to grains of yeast by the transformation of albuminous matter, whilst m. pasteur declares that the grains of yeast are produced by germs.” according to m. frémy, ferments did not come from atmospheric dusts, but were created by organic bodies. and, inventing for his own use the new word hemiorganism, m. frémy explained the word and the action by saying that there are some hemiorganized bodies which, by reason of the vital force with which they are endowed, go through successive decompositions and give birth to new derivatives; thus are ferments engendered.

another colleague, m. trécul, a botanist and a genuine truth-seeking savant, arose in his turn. he said he had witnessed a whole transformation of microscopic species each into the other, and in support of this theory he invoked the names of the three inseparables—pouchet, musset and joly. himself a heterogenist, he had in 1867 given a definition to which he willingly alluded: “heterogenesis is a natural operation by which life, on the point of abandoning an organized body, concentrates its action on some particles of that body and forms thereof beings quite different from that of the substance which has been borrowed.”

old arguments and renewed negations were brought forward, and pasteur knew well that this was but a reappearance of the old quarrel; he therefore answered by going straight to the point. at the académie des sciences, on december 26, 1871, he addressed m. trécul in these words: “i can assure our learned colleague that he might have found in the treatises i have published decisive answers to most of the questions he has raised. i am really surprised to see him tackle the question of so-called spontaneous generation, without having more at his disposal than doubtful facts and incomplete observations. my astonishment was not less than at our last sitting, when m. frémy entered upon the same debate with nothing to produce but superannuated opinions and not one new positive fact.”

in his passion for truth and his desire to be convincing pasteur threw out this challenge: “would m. frémy confess his error if i were to demonstrate to him that the natural juice of the grape, exposed to the contact of air, deprived of its germs, can neither ferment nor give birth to organized yeasts?” this interpellation was perhaps more violent than{217} was usual in the meetings of the solemn academy, but scientific truth was in question. and pasteur, recognizing the old arguments under m. frémy’s hemiorganism and m. trécul’s transformations, referred his two contradictors to the experiments by which he had proved that alterable liquids, such as blood or urine, could be exposed to the contact of air deprived of its germs without undergoing the least fermentation or putrefaction. had not this fact been the basis on which lister had founded “his marvellous surgical method”? and in the bitterness given to his speech by his irritation against error, the epithet “marvellous” burst out with a visible delight in rendering homage to lister.

pasteur, then in full possession of all the qualities of his genius, was feeling the sort of fever known to great scientists, great artists, great writers: the ardent desire of finding, of discovering something he could leave to posterity. interrupted by these belated contradictors when he wanted to be going forward, he only restrained his impatience with difficulty.

his old master, balard, appealed to him in the académie itself (january 22, 1872), in the name of their old friendship, to disregard the attacks of his adversaries, instead of wasting his time and his strength in trying to convince them. he reminded him of all he had achieved, of the benefits he had brought to the industries of wine, beer, vinegar, silkworms, etc., and alluded to the possibility foreseen by pasteur himself of preserving mankind from some of the mysterious diseases which were perhaps due to germs in atmospheric air. he ended by urging him to continue his studies peacefully in the laboratory built for him, and to continue the scientific education of young pupils who might one day become worthy successors of van tieghem, duclaux, gernez, raulin, etc.... thus forming a whole generation of young scientists instructed in pasteur’s school.

m. duclaux wrote to him in the same sense: “i see very well what you may lose in that fruitless struggle—your rest, your time and your health; i try in vain to see any possible advantage.”

but nothing stopped him; neither balard’s public advice, his pupils’ letters, even j. b. dumas’ imploring looks. he could not keep himself from replying. sometimes he regretted his somewhat sharp language, though—in his own words—he never associated it with feelings of hostility towards his{218} contradictors as long as he believed in their good faith; what he wanted was that truth should have the last word. “what you lack, m. frémy, is familiarity with a microscope, and you, m. trécul, are not accustomed to laboratories!” “m. frémy is always trying to displace the question,” said pasteur, ten months after m. balard’s appeal.

whilst m. frémy disputed, discussed, and filled the académie with his objections, m. trécul, whose life was somewhat misanthropical and whose usually sad and distrustful face was seen nowhere but at the institute, insisted slowly, in a mournful voice, on certain transformations of divers cells or spores from one into the other. pasteur declared that those ideas of transformation were erroneous; but—and there lay the interest of the debate—there was one of those transformations that pasteur himself had once believed possible: that of the mycoderma vini, or wine flower, into an alcoholic ferment under certain conditions of existence.

a modification in the life of the mycoderma when submerged had led him to believe in a transformation of the mycoderma cells into yeast cells. it was on this question, which had been left in suspense, that the debate with trécul came to an end, leaving to the witnesses of it a most vivid memory of pasteur’s personality—inflexible when he held his proofs, full of scruples and reserve when seeking those proofs, and accepting no personal praise if scientific truth was not recognized and honoured before everything else.

on november 11 pasteur said: “four months ago doubts suddenly appeared in my mind as to the truth of the fact in question, and which m. trécul still looks upon as indisputable.... in order to disperse those doubts i have instituted the most numerous and varied experiments and i have not succeeded through those four months in satisfying myself by irrefragable proofs; i still have my doubts. let this example show to m. trécul how difficult it is to conclude definitely in such delicate studies.”

pasteur studied the scientific point for a long time, for he never abandoned a subject, but was ever ready to begin again after a failure. he modified the disposition of his first tests, and by the use of special vessels and slightly complicated apparatus succeeded in eliminating the only imaginable cause of error—the possible fall, during the manipulations, of exterior germs, that is, the fortuitous sowing of yeast cells. after that{219} he saw no more yeast and no more active alcoholic fermentation; he had therefore formerly been the dupe of a delusion. in his studies on beer pasteur tells of his error and its rectification: “at a time when ideas on the transformations of species are so readily adopted, perhaps because they dispense with rigorous experimentation, it is somewhat interesting to consider that in the course of my researches on microscopic plants in a state of purity i once had occasion to believe in the transformation of one organism into another, the transformation of the mycoderma vini or cerevisiae into yeast, and that this time i was in error; i had not avoided the cause of illusion which my confirmed confidence in the theory of germs had so often led me to discover in the observations of others.”

“the notion of species,” writes m. duclaux, who was narrowly associated with those experiments, “was saved for the present from the attacks directed against it, and it has not been seriously contested since, at least not on that ground.”

some failures are blessings in disguise. when discovering his mistake, pasteur directed his attention to a strange phenomenon. we find in his book on beer—a sort of laboratory diary—the following details on his observation of the growth of some mycoderma seed which he had just scattered over some sweetened wine or beer-wort in small china saucers.

“when the cells or articles of the mycoderma vini are in full germinating and propagating activity in contact with air on a sweetened substratum, they live at the expense of that sugar and other subjacent materials absolutely like the animals who also utilize the oxygen in the air while freeing carbonic acid gas, consuming this and that, and correlatively increasing, regenerating themselves and creating new materials.

“under those conditions not only does the mycoderma vini form no alcohol appreciable by analysis, but if alcohol exists in the subjacent liquid the mycoderma reduces it to water and carbonic acid gas by the fixation of the oxygen in the air.” pasteur, having submerged the mycoderma and studied it to see how it would accommodate itself to the new conditions offered to it, and whether it would die like an animal asphyxiated by the sudden deprivation of oxygen, saw that life was continued in the submerged cells, slow, difficult, of a short duration, but undoubtedly life, and that this life was accompanied by alcoholic fermentation. this time fermentation was due to the fungus itself. the mycoderma, originally an{220} a?robia—that is, a being to the life and development of which air was necessary—became, after being submerged, an ana?robia, that is, a creature living without air in the depths of the liquid, and behaving after the manner of ferments.

this extended the notions on a?robi? and ana?robi? which pasteur had formerly discovered whilst making researches concerning the vibrio which is the butyric ferment, and those vibriones which are entrusted with the special fermentation known as putrefaction. between the a?robi? who require air to live and the ana?robi? which perish when exposed to air, there was a class of organisms capable of living for a time outside the influence of air. no one had thought of studying the mouldiness which develops so easily when in contact with air; pasteur was curious to see what became of it when submitted like the mycoderma to that unexpected régime. he saw the penicillium, the aspergillus, the mucor-mucedo take the character of ferments when living without air, or with a quantity of air too small to surround their organs as completely as was necessary to their a?robia-plant life. the mucor, when submerged and thus forced to become an ana?robia, offers budding cells, and there again it seemed as if they were yeast globules. “but,” said pasteur, “this change of form merely corresponds to a change of function, it is but a self-adaptation to the new life of an ana?robia.” and then, generalizing again and seeking for laws under the accumulation of isolated facts, he thought it probable that ferments had, “but in a higher degree, a character common to most mucors if not to all, and probably possessed more or less by all living cells, viz., to be alternately a?robic or ana?robic, according to conditions of environment.”

fermentation, therefore, no longer appeared as an isolated and mysterious act; it was a general phenomenon, subordinate however to the small number of substances capable of a decomposition accompanied by a production of heat and of being used for the alimentation of inferior beings outside the presence and action of air. pasteur put the whole theory into this concise formula, “fermentation is life without air.”

“it will be seen,” wrote m. duclaux, “to what heights he had raised the debate; by changing the mode of interpretation of known facts he brought out a new theory.”

but this new theory raised a chorus of controversy. pasteur held to his proofs; he recalled what he had published concern{221}ing the typical ferment, the yeast of beer, an article inserted in the reports of the académie des sciences for 1861, and entitled, the influence of oxygen on the development of yeast and on alcoholic fermentation. in this article pasteur, à propos of the chemical action connected with vegetable life, explained in the most interesting manner the two modes of life of the yeast of beer.

1. the yeast, placed in some sweet liquid in contact with air, assimilates oxygen gas and develops abundantly; under those conditions, it practically works for itself only, the production of alcohol is insignificant, and the proportion between the weight of sugar absorbed and that of the yeast is infinitesimal. 2. but, in its second mode of life, if yeast is made to act upon sugar without the action of atmospheric air, it can no longer freely assimilate oxygen gas, and is reduced to abstracting oxygen from the fermentescible matter.

“it seems therefore natural,” wrote pasteur, “to admit that when yeast is a ferment, acting out of the reach of atmospheric air, it takes oxygen from sugar, that being the origin of its fermentative character.” it is possible to put the fermentative power of yeast through divers degrees of intensity by introducing free oxygen in variable quantities.

after comparing the yeast of beer to an ordinary plant, pasteur added that “the analogy would be complete if ordinary plants had an affinity for oxygen so strong as to breathe, by withdrawing that element from unstable components, in which case they would act as ferments on those substances.” he suggested that it might be possible to meet with conditions which would allow certain inferior plants to live away from atmospheric air in the presence of sugar, and to provoke fermentation of that substance after the manner of beer yeast.

he was already at that time scattering germs of ideas, with the intention of taking them up later on and experimenting on them, or, if time should fail him, willingly offering them to any attentive scientist. these studies on beer had brought him back to his former studies, to his great delight.

“what a sacrifice i made for you,” he could not help saying to dumas, with a mixture of affection and deference, and some modesty, for he apparently forgot the immense service rendered to sericiculture, “when i gave up my studies on ferments for five whole years in order to study silkworms!!!”

no doubt a great deal of time was also wasted by the endless{222} discussions entered into by his scientific adversaries; but those discussions certainly brought out and evidenced many guiding facts which are now undisputed, as for instance the following—1. ferments are living beings. 2. there is a special ferment corresponding to each kind of fermentation. 3. ferments are not born spontaneously.

liebig and his partisans had looked upon fermentation as a phenomenon of death; they had thought that beer yeast, and in general all animal and vegetable matter in a state of putrefaction, extended to other bodies its own state of decomposition.

pasteur, on the contrary, had seen in fermentation a phenomenon correlative with life; he had provoked the complete fermentation of a sweet liquid which contained mineral substances only, by introducing into it a trace of yeast, which, instead of dying, lived, flourished and developed.

to those who, believing in spontaneous generation, saw in fermentations but a question of chance, pasteur by a series of experimental proofs had shown the origin of their delusion by indicating the door open to germs coming from outside. he had moreover taught the method of pure cultures. finally, in those recent renewals of old quarrels on the transformations into each other of microscopic species, pasteur, obliged by the mycoderma vini to study closely its alleged transformation, which he had himself believed possible, had thrown ample light on the only dark spot of his luminous domain.

“it is enough to think,” writes m. duclaux concerning that long discussion, “we have but to remember that those who denied the specific nature of the germ would now deny the specific nature of disease, in order to understand the darkness in which such opinions would have confined microbian pathology; it was therefore important that they should be uprooted from every mind.{223}”