1844--1849
Pasteur often spent his leisure moments in the library of the Ecole
Normale. Those who knew him at that time remember him as grave, quiet,
almost shy. But under these reflective characteristics lay the latent
fire of enthusiasm. The lives of illustrious men, of great scientists,
of great patriots inspired him with a generous ardour. To this ardour he
added a great eagerness of mind; whether studying a book, even a
commonplace one--for he was so conscientious that he did not even know
what it was to “skim” through a book--or coming away from one of J. B.
Dumas’ lectures, or writing his student’s notes in his small fine
handwriting, he was always thirsting to learn more, to devote himself to
great researches. There seemed to him no better way of spending a
holiday than to be shut up all Sunday afternoon at the Sorbonne
laboratory or coaxing a private lesson from the celebrated Barruel,
Dumas’ curator.
Chappuis--anxious to obey the injunctions of Pasteur’s father, who in
every letter repeated “Do not let him work too much!” desirous also of
enjoying a few hours’ outing with his friend--used to wait
philosophically, sitting on a laboratory stool, until the experiments
were over. Conquered by this patient attitude and reproachful silence
Pasteur would take off his apron, saying half angrily, half gratefully,
“Well, let us go for a walk.” And, when they were out in the street, the
same serious subjects of conversation would inevitably crop up--classes,
lectures, readings, etc.
One day, in the course of those long talks in the gardens of the
Luxembourg, Pasteur carried Chappuis with him very far away from
philosophy. He began to talk of tartaric acid and of paratartaric acid.
The former had been known since 1770, thanks to the Swedish chemist
Scheele, who discovered it in the thick crusty formations within wine
barrels called “tartar”; but the latter was disconcerting to chemists.
In 1820 an Alsatian manufacturer, Kestner, had obtained by chance,
whilst preparing tartaric acid in his factory at Thann, a very singular
acid which he was unable to reproduce in spite of various attempts. He
had kept some of it in stock. Gay-Lussac, having visited the Thann
factory in 1826, studied this mysterious acid; he proposed to call it
_racemic_ acid. Berzelius studied it in his turn, and preferred to call
it _paratartaric_. Either name may be adopted; it is exactly the same
thing: men of letters or in society are equally frightened by the word
paratartaric or racemic. Chappuis certainly was when Pasteur repeated to
him word for word a paragraph by a Berlin chemist and crystallographer
named Mitscherlich. Pasteur had pondered over this paragraph until he
knew it by heart; often indeed, absorbed in reading the reports for 1844
of the Académie des Sciences, in the dark room which was then the
library of the Ecole Normale, he had wondered if it were possible to get
over a difficulty which seemed insurmountable to scientists such as
Mitscherlich and Biot. This paragraph related to two saline
combinations--tartrate and paratartrate of soda or ammonia--and may be
epitomized as follows: in these two substances of similar crystalline
form, the nature and number of the atoms, their arrangement and
distances are the same. Yet dissolved tartrate rotates the plane of
polarized light and paratartrate remains inactive.
Pasteur had the gift of making scientific problems interesting in a few
words, even to minds least inclined to that particular line of thought.
He rendered his listener’s attention very easy; no question surprised
him and he never smiled at ignorance. Though Chappuis, absorbed in the
series of lectures on philosophy given at that time by Jules Simon, was
deep in a train of thought very far away from Mitscherlich’s
perplexities, he gradually became interested in this optical inactivity
of paratartrate, which so visibly affected his friend. Pasteur liked to
look back into the history of things, giving in this way a veritable
life to his explanations. Thus, à propos of the optical phenomenon which
puzzled Mitscherlich, Pasteur was speaking to his friend of crystallized
carbonate of lime, called Iceland spar, which presents a double
refraction--that is to say: if you look at an object through this
crystal, you perceive two reproductions of that object. In describing
this, Pasteur was not giving to Chappuis a vague notion of some piece
of crystal in a glass case, but was absolutely evoking a vision of the
beautiful crystal, perfectly pure and transparent, brought from Iceland
in 1669 to a Danish physicist. Pasteur almost seemed to experience the
surprise and emotion of this scientist, when, observing a ray of light
through this crystal, he saw it suddenly duplicated. Pasteur also spoke
enthusiastically of an officer of Engineers under the First Empire,
Etienne Louis Malus. Malus was studying double refraction, and holding
in his hands a piece of spar crystal, when, from his room in the Rue de
l’Enfer, it occurred to him to observe through the crystal the windows
of the Luxembourg Palace, then lighted up by the setting sun. It was
sufficient to make the crystal rotate slowly round the visual ray (as on
an axis) to perceive the periodic variations in the intensity of the
light reflected by the windows. No one had yet suspected that light,
after being reflected under certain conditions, would acquire properties
quite different from those it had before its reflection. Malus gave the
name of polarized light to light thus modified (by reflection in this
particular case). Scientists admitted in those days, in the theory of
emission, the existence of luminous molecules, and they imagined that
these molecules “suffered the same effects simultaneously when they had
been reflected on glass at a certain angle.... They were all turned in
the same direction.” Pouillet, speaking of this discovery of Malus in
the class on physics that Pasteur attended, explained that the
consequent persuasion was “that those molecules had rotatory axes and
poles, around which their movements could be accomplished under certain
influences.”
Pasteur spoke feverishly of his regrets that Malus should have died at
thirty-seven in the midst of his researches; of Biot, and of Arago, who
became illustrious in the path opened by Malus. He explained to Chappuis
that, by means of a polarizing apparatus, it could be seen that certain
quartz crystals deflected to the right the plane of polarized light,
whilst others caused it to turn to the left. Chappuis also learned that
some natural organic material, such as solutions of sugar or of tartaric
acid, when placed in such an apparatus, turned to the right the plane of
polarization, whilst others, like essence of turpentine or quinine,
deflected it to the left; whence the expression “rotatory polarization.”
These would seem dry researches, belonging altogether to the domain of
science. And yet, thanks to the saccharimeter, which is a polarizing
apparatus, a manufacturer can ascertain the quantity of pure sugar
contained in the brown sugar of commerce, and a physiologist can follow
the progress of diabetes.
Chappuis, who knew what powers of investigation his friend could bring
to bear on the problem enunciated by Mitscherlich, thought with regret
that the prospect of such examinations as that for the _licence_ and for
the _agrégation_ did not allow Pasteur to concentrate all his forces on
such a special scientific point. But Pasteur was resolved to come back
definitely to this subject as soon as he should have become “_docteur ès
sciences_.”
When writing to his father he did not dwell upon tartrate and
paratartrate; but his ambition was palpable. He was ever eager to do
double work, to go up for his examination at the very earliest. “Before
being a captain,” answered the old sergeant-major, “you must become a
lieutenant.”
These letters give one the impression of living amongst those lives,
perpetually reacting upon each other. The thoughts of the whole family
were centred upon the great School, where that son, that brother, was
working, in whom the hopes of each were placed. If one of his bulky
letters with the large post mark was too long in coming, his father
wrote to reproach him gently: “Your sisters were counting the days.
Eighteen days, they said! Louis has never kept us waiting so long! Can
he be ill? It is a great joy to me,” adds the father, “to note your
attachment to each other. May it always remain so.”
The mother had no time to write much; she was burdened with all the
cares of the household and with keeping the books of the business. But
she watched for the postman with a tender anxiety increased by her vivid
imagination. Her thoughts were ever with the son whom she loved, not
with a selfish love, but for himself, sharing his happiness in that he
was working for a useful career.
So, between that corner in the Jura and the Ecole Normale, there was a
continual exchange of thoughts; the smallest incidents of daily life
were related. The father, knowing that he should inform the son of the
fluctuations of the family budget, spoke of his more or less successful
sales of leathers at the Besançon fair. The son was ever hunting in the
progress of industry anything that could tend to lighten the father’s
heavy handicraft. But though the father declared himself ready to
examine Vauquelin’s new tanning process, which obviated the necessity of
keeping the skins so long in the pits, he asked himself with scrupulous
anxiety whether leathers prepared in that way would last as long as the
others. Could he safely guarantee them to the shoemakers, who were
unanimous in praising the goods of the little tannery-yard, but alas
equally unanimous in forgetting to reward the disinterested tanner by
prompt payment? He supplied his family with the necessaries of life:
what more did he want? When he had news of his _Normalien_ he was
thoroughly happy. He associated himself with his son’s doings, sharing
his enthusiasm over Dumas’ lectures, and taking an interest in
Pouillet’s classes: Pouillet was a Franc-Comtois, and had been a student
at the Ecole Normale; he was now Professor of Physics at the Sorbonne
and a member of the _Institut_.[10] When Balard, a lecturer at the
Ecole, was nominated to the Académie des Sciences, Louis told his father
of it with the delight of an admiring pupil.
Like J. B. Dumas, Balard had been an apothecary’s pupil. When he spoke
of their humble beginnings, Dumas was wont to say rather
pompously--“Balard and I were initiated into our scientific life under
the same conditions.” When, at the age of forty-two, he was made a
member of the Institute, Balard could not contain his joy; he was quite
a Southerner in his language and gestures, and the adjective _exubérant_
might have been invented for him. But this same Southerner, ever on the
move as he was, belonged to a special race: he always kept his word. “I
was glad to note your pleasure at this nomination,” wrote Joseph Pasteur
to his son; “it proves that you are grateful to your masters.” About
that same time the headmaster of Arbois College, M. Romanet, used to
read out to the older boys the letters, always full of gratitude, which
he received from Louis Pasteur. These letters reflected life in Paris,
such as Pasteur understood it--a life of hard work and exalted ambition.
M. Romanet, in one of his replies, asked him to become librarian _in
partibus_ for the college and to choose and procure books on science and
literature. The headmaster also begged of the young man some lectures
for the _rhétorique_ class during the holidays. “It would seem to the
boys like an echo of the Sorbonne lectures! And you would speak to us of
our great scientific men,” added M. Romanet, “amongst whom we shall one
day number him who once was one of our best pupils and will ever remain
one of our best friends.”
A corresponding member of Arbois College, and retained as vacation
lecturer, Pasteur now undertook a yet more special task. He had often
heard his father deplore his own lack of instruction, and knew well the
elder man’s desire for knowledge. By a touching exchange of parts, the
child to whom his father had taught his alphabet now became his father’s
teacher; but with what respect and what delicacy did this filial master
express himself! “It is in order that you may be able to help Josephine
that I am sending you this work to do.” He took most seriously his task
of tutor by correspondence; the papers he sent were not always easy. His
father wrote (Jan. 2, 1845)--“I have spent two days over a problem which
I afterwards found quite easy; it is no trifle to learn a thing and
teach it directly afterwards.” And a month later: “Josephine does not
care to rack her brains, she says; however I promise you that you will
be pleased with her progress by the next holidays.”
The father would often sit up late at night over rules of grammar and
mathematical problems, preparing answers to send to his boy in Paris.
Some Arboisians, quite forgotten now, imagined that they would add
lustre to the local history. General Baron Delort, a peer of France,[11]
aide de camp to Louis Philippe, Grand Cross of the Legion of Honour and
the first personage in Arbois--where he beguiled his old age by
translating Horace--used to go across the Cuisance bridge without so
much as glancing at the tannery where the Pasteur family lived. Whilst
the general in his thoughts bequeathed to the town of Arbois his books,
his papers, his decorations, even his uniform, he was far from
foreseeing that the little dwelling by the bridge would one day become
the cynosure of all eyes.
Months went by and happy items of news succeeded one another. The
_Normalien_ was chiefly interested in the transformations of matter, and
was practising in order to become capable of assisting in experiments;
difficulties only stimulated him. At the chemistry class that he
attended, the process of obtaining phosphorus was merely explained, on
account of the length of time necessary to obtain this elementary
substance; Pasteur, with his patience and desire for proven knowledge,
was not satisfied. He therefore bought some bones, burnt them, reduced
them to a very fine ash, treated this ash with sulphuric acid, and
carefully brought the process to its close. What a triumph it seemed to
him when he had in his possession sixty grammes of phosphorus, extracted
from bones, which he could put into a phial labelled “phosphorus.” This
was his first scientific joy.
Whilst his comrades ironically (but with some discernment) called him a
“laboratory pillar,” some of them, more intent upon their examinations,
were getting ahead of him.--M. Darboux, the present “doyen” of the
Faculty[12] of Science, finds in the Sorbonne registers that Pasteur was
placed 7th at the _licence_ examination; two other students having
obtained equal marks with him, the jury (Balard, Dumas and Delafosse),
mentioned his name after theirs.
Those who care for archives would find in the _Journal Général de
l’Instruction Publique_ of September 17, 1846, a report of the
_agrégation_[13] competition (physical science). Out of fourteen
candidates only four passed and Pasteur was the third. His lessons on
physics and chemistry caused the jury to say, “He will make an excellent
professor.”
Many _Normaliens_ of that time fancied themselves called to a destiny
infinitely superior to his. Some of them, in later times, used to
complacently allude to this momentary superiority when speaking to their
pupils. Of all Pasteur’s acquaintances Chappuis was the only one who
divined the future. “You will see what Pasteur will be,” he used to say,
with an assurance generally attributed to friendly partiality.
Chappuis--Pasteur’s confidant--was well aware of his friend’s powers of
concentration.
Balard also realised this; he had the happy idea of taking the young
_agrégé_ into his laboratory, and intervened vehemently when the
Minister of Public Instruction desired--a few months later--that Pasteur
should teach physics in the Tournon Lycée. It would be rank folly,
Balard declared, to send 500 kilometres away from Paris a youth who only
asked for the modest title of curator, and had no ambition but to work
from morning till night, preparing for his doctor’s degree. There would
be time to send him away later on. It was impossible to resist this
torrent of words founded on solid sense. Balard prevailed.
Pasteur was profoundly grateful to him for preserving him from exile to
the little town in Ardèche; and, as he added to his Franc-Comtois
patience and reflective mind a childlike heart and deep enthusiasm, he
was delighted to remain with a master like Balard, who had become
celebrated, at the age of twenty-four, as the discoverer of bromin.
At the end of 1846, a newcomer entered Balard’s laboratory, a strange
delicate-looking man, whose ardent eyes were at the same time proud and
yet anxious. This man, a scientist and a poet, was a professor of the
Bordeaux Faculty, named Auguste Laurent. Perhaps he had had some
friction with his Bordeaux chiefs, possibly he merely wished for a
change; at all events, he now desired to live in Paris. Laurent was
already known in the scientific world, and had recently been made a
correspondent of the Académie des Sciences. He had foreseen and
confirmed the theory of substitutions, formulated by Dumas as early as
1834 before the Académie. Dumas had expressed himself thus: “Chlorine
possesses the singular power of seizing upon the hydrogen in certain
substances, and of taking its place atom by atom.”
This theory of substitutions was--according to a simple and vivid
comparison of Pasteur’s--a way of looking upon chemical bodies as upon
“molecular edifices, in which one element could be replaced by another
without disturbing the structure of the edifice; as if one were to
replace, one by one, every stone of a monument by a new stone.” Original
researches, new and bold ideas, appealed to Pasteur. But his cautious
mind prevented his boldness from leading him into errors, surprises or
hasty conclusions. “That is possible,” he would say, “but we must look
more deeply into the subject.”
When asked by Laurent to assist him with some experiments upon certain
theories, Pasteur was delighted at this suggested collaboration, and
wrote to his friend Chappuis: “Even if the work should lead to no
results worth publishing, it will be most useful to me to do practical
work for several months with such an experienced chemist.”
It was partly due to Laurent, that Pasteur entered more deeply into the
train of thought which was to lead him to grapple with Mitscherlich’s
problem. “One day” (this is a manuscript note of Pasteur’s) “one day it
happened that M. Laurent--studying, if I mistake not, some tungstate of
soda, perfectly crystallized and prepared from the directions of another
chemist, whose results he was verifying--showed me through the
microscope that this salt, apparently very pure, was evidently a mixture
of three distinct kinds of crystals, easily recognizable with a little
experience of crystalline forms. The lessons of our modest and excellent
professor of mineralogy, M. Delafosse, had long since made me love
crystallography; so, in order to acquire the habit of using the
goniometer, I began to carefully study the formations of a very fine
series of combinations, all very easily crystallized, tartaric acid and
the tartrates.” He appreciated any favourable influence on his work; we
find in the same note: “Another motive urged me to prefer the study of
those particular forms. M. de la Provostaye had just published an almost
complete work concerning them; this allowed me to compare as I went
along my own observations with those, always so precise, of that clever
scientist.”
Pasteur and Laurent’s work in common was interrupted. Laurent was
appointed as Dumas’ assistant at the Sorbonne. Pasteur did not dwell
upon his own disappointment, but rejoiced to see honour bestowed upon a
man whom he thought worthy of the first rank. Some judges have thought
that Laurent, in his introductory lesson, was too eager to expound his
own ideas; but is not every believer an apostle? When a mind is full of
ideas, it naturally overflows. It is probable that Pasteur in Laurent’s
place would have kept his part as an assistant more in the background.
He did not give vent to the slightest criticism, but wrote to Chappuis.
“Laurent’s lectures are as bold as his writings, and his lessons are
making a great sensation amongst chemists.” Whether one of criticism or
of approbation, this sensation was a living element of success. In order
to answer some insinuations concerning Laurent’s ambition and constant
thirst for change, Pasteur proclaimed in his thesis on chemistry how
much he had been “enlightened by the kindly advice of a man so
distinguished, both by his talent and by his character.”
This essay was entitled “_Researches into the saturation capacity of
arsenious acid. A study of the arsenites of potash, soda and ammonia._”
This, to Pasteur’s mind, was but schoolboy work. He had not yet, he
said, enough practice and experience in laboratory work. “In physics,”
he wrote to Chappuis, “I shall only present a programme of some
researches that I mean to undertake next year, and that I merely
indicate in my essay.”
This essay on physics was a “_Study of phenomena relative to the
rotatory polarization of liquids_.” In it he rendered full homage to
Biot, pointing out the importance of a branch of science too much
neglected by chemists; he added that it was most useful, in order to
throw light upon certain difficult chemical problems, to obtain the
assistance of crystallography and physics. “Such assistance is
especially needed in the present state of science.”
These two essays, dedicated to his father and mother, were read on
August 23, 1847. He only obtained one white ball and two red ones for
each. “We cannot judge of your essays,” wrote his father, in the name of
the whole family, “but our satisfaction is no less great. As to a
doctor’s degree, I was far from hoping as much; all _my_ ambition was
satisfied with the _agrégation_.” Such was not the case with his son.
“Onwards” was his motto, not from a desire for a diploma, but from an
insatiable thirst for knowledge.
After spending a few days with his family and friends, he wanted to go
to Germany with Chappuis to study German from morning till night. The
prospect of such industrious holidays enchanted him. But he had
forgotten a student’s debt. “I cannot carry out my project,” he sadly
wrote, on September 3, 1847; “I am more than ruined by the cost of
printing my thesis.”
On his return to Paris he shut himself up in the laboratory. “I am
extremely happy. I shall soon publish a paper on crystallography.” His
father writes (December 25, 1847): “We received your letter yesterday;
it is absolutely satisfactory, but it could not be otherwise coming from
you; you have long, indeed ever, been all satisfaction to me.” And in
response to his son’s intentions of accomplishing various tasks, fully
understanding that nothing will stop him: “You are doing right to make
for your goal; it was only out of excessive affection that I have often
written in another sense. I only feared that you might succumb to your
work; so many noble youths have sacrificed their health to the love of
science. Knowing you as I do, this was my only anxiety.”
After being reproved for excessive work, Louis was reprimanded for too
much affection (January 1, 1848). “The presents you sent have just
arrived; I shall leave it to your sisters to write their thanks. For my
part, I should prefer a thousand times that this money should still be
in your purse, and thence to a good restaurant, spent in some good meals
that you might have enjoyed with your friends. There are not many
parents, my dearest boy, who have to write such things to their son; my
satisfaction in you is indeed deeper than I can express.” At the end of
this same letter, the mother adds in her turn: “My darling boy, I wish
you a happy new year. Take great care of your health.... Think what a
worry it is to me that I cannot be with you to look after you. Sometimes
I try to console myself for your absence by thinking how fortunate I am
in having a child able to raise himself to such a position as yours
is--such a happy position, as it seems to be from your last letter but
one.” And in a strange sentence, where it would seem that a presentiment
of her approaching death made worldly things appear at their true
value: “Whatever happens to you, do not grieve; nothing in life is more
than a chimera. Farewell, my son.”
On March 20, 1848, Pasteur read to the Académie des Sciences a portion
of his treatise on “_Researches on Dimorphism_.” There are some
substances which crystallize in two different ways. Sulphur, for
instance, gives quite dissimilar crystals according to whether it is
melted in a crucible or dissolved in sulphide of carbon. Those
substances are called dimorphous. Pasteur, kindly aided by the learned
M. Delafosse (with his usual gratefulness he mentions this in the very
first pages) had made out a list--as complete as possible--of all
dimorphous substances. When M. Romanet, of Arbois College, received this
paper he was quite overwhelmed. “It is much too stiff for you,” he said
with an infectious modesty to Vercel, Charrière, and Coulon, Pasteur’s
former comrades. Perhaps the head master desired to palliate his own
incompetence in the eyes of coming generations, for on the title page of
the copy of Pasteur’s booklet still to be found in the Arbois
library, he wrote this remark, which he signed with his initial
R.:--“_Dimorphisme_; this word is not even to be found in the
_Dictionnaire de l’Académie_”!! The approbation of several members of
the Académie des Sciences compensated for the somewhat summary judgment
of M. Romanet, whose good wishes continued to follow the rapid course of
his old pupil.
After this very special study, dated at the beginning of 1848, one might
imagine the graduate-curator closing his ears to all outside rumours and
little concerned with political agitation, but that would be doing him
an injustice. Those who witnessed the Revolution of 1848 remember how
during the early days France was exalted with the purest patriotism.
Pasteur had visions of a generous and fraternal Republic; the words
_drapeau_ and _patrie_ moved him to the bottom of his soul.
Lamartine[14] as a politician inspired him with an enthusiastic
confidence; he delighted in the sight of a poet leader of men. Many
others shared the same illusions. France, as Louis Veuillot has it, made
the mistake of choosing her band-master as colonel of the regiment.
Enrolled with his fellow students, Pasteur wrote thus to his parents: “I
am writing from the Orleans Railway, where as a _garde national_[15] I
am stationed. I am glad that I was in Paris during the February days[16]
and that I am here still; I should be sorry to leave Paris just now. It
is a great and a sublime doctrine which is now being unfolded before our
eyes ... and if it were necessary I should heartily fight for the holy
cause of the Republic.” “What a transformation of our whole being!” has
written one who was then a candidate to the Ecole Normale, already noted
by his masters for his good sense, Francisque Sarcey. “How those magical
words of liberty and fraternity, this renewal of the Republic, born in
the sunshine of our twentieth year, filled our hearts with unknown and
absolutely delicious sensations! With what a gallant joy we embraced the
sweet and superb image of a people of free men and brethren! The whole
nation was moved as we were; like us, it had drunk of the intoxicating
cup. The honey of eloquence flowed unceasingly from the lips of a great
poet, and France believed, in childlike faith, that his word was
efficacious to destroy abuses, cure evils and soothe sorrows.”
One day when Pasteur was crossing the Place du Panthéon, he saw a
gathering crowd around a wooden erection, decorated with the words:
_Autel de la Patrie_. A neighbour told him that pecuniary offerings
might be laid upon this altar. Pasteur goes back to the Ecole Normale,
empties a drawer of all his savings, and returns to deposit it in
thankful hands.
“You say,” wrote his father on April 28, 1848, “that you have offered to
France all your savings, amounting to 150 francs. You have probably kept
a receipt of the office where this payment was made, with mention of the
date and place?” And considering that this action should be made known,
he advises him to publish it in the journal _Le National_ or _La
Réforme_ in the following terms, “Gift to the _Patrie_: 150 francs, by
the son of an old soldier of the Empire, Louis Pasteur of the Ecole
Normale.” He wrote in the same letter, “You should raise a subscription
in your school in favour of the poor Polish exiles who have done so much
for us; it would be a good deed.”
After those days of national exaltation, Pasteur returned to his
crystals. He studied tartrates under the influence of certain ideas that
he himself liked to expound. Objects considered merely from the point of
view of form, may be divided into two great categories. First, those
objects which, placed before a mirror, give an image which can be
superposed to them: these have a symmetrical plan; secondly, those which
have an image which cannot be superposed to them: they are
dissymmetrical. A chair, for instance, is symmetrical, or a straight
flight of steps. But a spiral staircase is not symmetrical, its own
image cannot be laid over it. If it turns to the right, its image turns
to the left. In the same way the right hand cannot be superposed to the
left hand, a righthand glove does not fit a left hand, and a right hand
seen in a mirror gives the image of a left hand.
Pasteur noticed that the crystals of tartaric acid and the tartrates had
little faces, which had escaped even the profound observation of
Mitscherlich and La Provostaye. These faces, which only existed on one
half of the edges or similar angles, constituted what is called a
hemihedral form. When the crystal was placed before a glass the image
that appeared could not be superposed to the crystal; the comparison of
the two hands was applicable to it. Pasteur thought that this aspect of
the crystal might be an index of what existed within the molecules,
dissymmetry of form corresponding with molecular dissymmetry.
Mitscherlich had not perceived that his tartrate presented these little
faces, this dissymmetry, whilst his paratartrate was without them, was
in fact not hemihedral. Therefore, reasoned Pasteur, the deviation to
the right of the plane of polarization produced by tartrate and the
optical neutrality of paratartrates would be explained by a structural
law. The first part of these conclusions was confirmed; all the crystals
of tartrate proved to be hemihedral. But when Pasteur came to examine
the crystals of paratartrate, hoping to find none of them hemihedral, he
experienced a keen disappointment. The paratartrate also was hemihedral,
but the faces of some of the crystals were inclined to the right, and
those of others to the left. It then occurred to Pasteur to take up
these crystals one by one and sort them carefully, putting on one side
those which turned to the left, and on the other those which turned to
the right. He thought that by observing their respective solutions in
the polarizing apparatus, the two contrary hemihedral forms would give
two contrary deviations; and then, by mixing together an equal number of
each kind, as no doubt Mitscherlich had done, the resulting solution
would have no action upon light, the two equal and directly opposite
deviations exactly neutralizing each other.
With anxious and beating heart he proceeded to this experiment with the
polarizing apparatus and exclaimed, “I have it!” His excitement was such
that he could not look at the apparatus again; he rushed out of the
laboratory, not unlike Archimedes. He met a curator in the passage,
embraced him as he would have embraced Chappuis, and dragged him out
with him into the Luxembourg garden to explain his discovery. Many
confidences have been whispered under the shade of the tall trees of
those avenues, but never was there greater or more exuberant joy on a
young man’s lips. He foresaw all the consequences of his discovery. The
hitherto incomprehensible constitution of paratartaric or racemic acid
was explained; he differentiated it into righthand tartaric acid,
similar in every way to the natural tartaric acid of grapes, and
lefthand tartaric acid. These two distinct acids possess equal and
opposite rotatory powers which neutralize each other when these two
substances, reduced to an aqueous solution, combine spontaneously in
equal quantities.
“How often,” he wrote to Chappuis (May 5), whom he longed to have with
him, “how often have I regretted that we did not both take up the same
study, that of physical science. We who so often talked of the future,
we did not understand. What splendid work we could have undertaken and
would be undertaking now; and what could we not have done united by the
same ideas, the same love of science, the same ambition! I would we
were twenty and with the three years of the Ecole before us!” Always
fancying that he could have done more, he often had such retrospective
regrets. He was impatient to begin new researches, when a sad blow fell
upon him--his mother died almost suddenly of apoplexy. “She succumbed in
a few hours,” he wrote to Chappuis on May 28, “and when I reached home
she had already left us. I have asked for a holiday.” He could no longer
work; he remained steeped in tears and buried in his sorrow. For weeks
his intellectual life was suspended.
* * * * *
In Paris, in the scientific world perhaps even more than in any other,
everything gets known, repeated, discussed. Pasteur’s researches were
becoming a subject of conversation. Balard, with his strident voice,
spoke of them in the library at the Institute, which is a sort of
drawing-room for talkative old Academicians. J. B. Dumas listened
gravely; Biot, old Biot, then seventy-four years old, questioned the
story with some scepticism. “Are you quite sure?” he would ask, his head
a little on one side, his words slow and slightly ironical. He could
hardly believe, on first hearing Balard, that a new doctor, fresh from
the Ecole Normale, should have overcome a difficulty which had proved
too much for Mitscherlich. He did not care for long conversations with
Balard, and as the latter continued to extol Pasteur, Biot said, “I
should like to investigate that young man’s results.”
Besides Pasteur’s deference for all those whom he looked upon as his
teachers, he also felt a sort of general gratitude for their services to
Science. Partly from an infinite respect and partly from an ardent
desire to convince the old scientist, he wrote on his return to Paris to
Biot, whom he did not know personally, asking him for an interview. Biot
answered: “I shall be pleased to verify your results if you will
communicate them confidentially to me. Please believe in the feelings of
interest inspired in me by all young men who work with accuracy and
perseverance.”
An appointment was made at the Collège de France,[17] where Biot lived.
Every detail of that interview remained for ever fixed in Pasteur’s
memory. Biot began by fetching some paratartaric acid. “I have most
carefully studied it,” he said to Pasteur; “it is absolutely neutral in
the presence of polarized light.” Some distrust was visible in his
gestures and audible in his voice. “I shall bring you everything that is
necessary,” continued the old man, fetching doses of soda and ammonia.
He wanted the salt prepared before his eyes.
After pouring the liquid into a crystallizer, Biot took it into a corner
of his room to be quite sure that no one would touch it. “I shall let
you know when you are to come back,” he said to Pasteur when taking
leave of him. Forty-eight hours later some crystals, very small at
first, began to form; when there was a sufficient number of them,
Pasteur was recalled. Still in Biot’s presence, Pasteur withdrew, one by
one, the finest crystals and wiped off the mother-liquor adhering to
them. He then pointed out to Biot the opposition of their hemihedral
character, and divided them into two groups--left and right.
“So you affirm,” said Biot, “that your righthand crystals will deviate
to the right the plane of polarization, and your lefthand ones will
deviate it to the left?”
“Yes,” said Pasteur.
“Well, let me do the rest.”
Biot himself prepared the solutions, and then sent again for Pasteur.
Biot first placed in the apparatus the solution which should deviate to
the left. Having satisfied himself that this deviation actually took
place, he took Pasteur’s arm and said to him these words, often
deservedly quoted: “My dear boy, I have loved Science so much during my
life, that this touches my very heart.”
“It was indeed evident,” said Pasteur himself in recalling this
interview, “that the strongest light had then been thrown on the cause
of the phenomenon of rotatory polarization and hemihedral crystals; a
new class of isomeric substances was discovered; the unexpected and
until then unexampled constitution of the racemic or paratartaric acid
was revealed; in one word a great and unforeseen road was opened to
science.”
Biot now constituted himself the sponsor in scientific matters of his
new young friend, and undertook to report upon Pasteur’s paper entitled:
“_Researches on the relations which may exist between crystalline form,
chemical composition, and the direction of rotatory power_”--destined
for the Académie des Sciences.
Biot did full justice to Pasteur; he even rendered him homage, and--not
only in his own name but also in that of his three colleagues, Regnault,
Balard, and Dumas--he suggested that the Académie should declare its
highest approbation of Pasteur’s treatise.
Pasteur did not conceive greater happiness than his laboratory life, and
yet the laboratories of that time were very unlike what they are
nowadays, as we should see if the laboratories of the Collège de France,
of the Sorbonne, of the Ecole Normale had been preserved. They were all
that Paris could offer Europe, and Europe certainly had no cause to
covet them. Nowadays the most humble college, in the smallest provincial
town, would not accept such dens as the State offered (when it offered
them any) to the greatest French scientists. Claude Bernard, Magendie’s
curator, worked at the Collège de France in a regular cellar. Wurtz only
had a lumber-room in the attics of the Dupuytren Museum. Henri Sainte
Claire Deville, before he became head of the Besançon Faculty, had not
even as much; he was relegated to one of the most miserable corners of
the Rue Lafarge. J. B. Dumas did not care to occupy the unhealthy room
reserved for him at the Sorbonne; his father-in-law, Alexandre
Brongniart, having given him a small house in the Rue Cuvier, opposite
the Jardin des Plantes, he had had it transformed into a laboratory and
was keeping it up at his own expense. He was therefore comfortably
situated, but he was exceptionally fortunate. Every scientist who had no
private means to draw upon had to choose between the miserable cellars
and equally miserable garrets which were all that the State could offer.
And yet it was more tempting than a Professor’s chair in a College or
even in a Faculty, for there one could not give oneself up entirely to
one’s work.
Nothing would have seemed more natural than to leave Pasteur to his
experiments. But his appointment to some definite post could no longer
be deferred, in spite of Balard’s tumultuous activity. The end of the
summer vacation was near, there was a vacancy: Pasteur was made a
Professor of Physics at the Dijon Lycée. The Minister of Public
Instruction consented to allow him to postpone his departure until the
beginning of November, in order to let him finish some work begun under
the eye of Biot, who thought and dreamt of nothing but these new
investigations. During thirty years Biot had studied the phenomena of
rotatory polarization. He had called the attention of chemists to these
phenomena, but his call had been unheeded. Continuing his solitary
labour, he had--in experimenting on cases both simple and
complex--studied this molecular rotatory power, without suspecting that
this power bore a definite relation to the hemihedral form of some
crystals. And now that the old man was a witness of a triumphant sequel
to his own researches, now that he had the joy of seeing a young man
with a thoughtful mind and an enthusiastic heart working with him, now
that the hope of this daily collaboration shed a last ray on the close
of his life, Pasteur’s departure for Dijon came as a real blow. “If at
least,” he said, “they were sending you to a Faculty!” He turned his
wrath on to the Government officials. “They don’t seem to realize that
such labours stand above everything else! If they only knew it, two or
three such treatises might bring a man straight to the Institut!”
Nevertheless Pasteur had to go. M. Pouillet gave him a letter for a
former Polytechnician,[18] now a civil engineer at Dijon, a M.
Parandier, in which he wrote--
“M. Pasteur is a most distinguished young chemist. He has just completed
some very remarkable work, and I hope it will not be long before he is
sent to a first-class Faculty. I need add nothing else about him; I know
no more honest, industrious, or capable young man. Help him as much as
you can at Dijon; you will not regret it.”
Those first weeks away from his masters and from his beloved pursuits
seemed very hard to Pasteur. But he was anxious to prove himself a good
teacher. This duty appeared to him to be a noble ideal, and to involve a
wide responsibility. He felt none of the self satisfaction which is
sometimes a source of strength to some minds conscious of their
superiority to others. He did not even do himself the justice of feeling
that he was absolutely sure of his subject. He wrote to Chappuis
(November 20, 1848): “I find that preparing my lessons takes up a great
deal of time. It is only when I have prepared a lesson very carefully
that I succeed in making it very clear and capable of compelling
attention. If I neglect it at all I lecture badly and become
unintelligible.”
He had both first and second year pupils; these two classes took up all
his time and all his strength. He liked the second class; it was not a
very large one. “They all work,” Pasteur wrote, “some very
intelligently.” As to the first year class, what could he do with eighty
pupils? The good ones were kept back by the bad. “Don’t you think,” he
wrote, “that it is a mistake not to limit classes to fifty boys at the
most? It is with great difficulty that I can secure the attention of all
towards the end of the lesson. I have only found one means, which is to
multiply experiments at the last moment.”
Whilst he was eagerly and conscientiously giving himself up to his new
functions--not without some bitterness, for he really was entitled to an
appointment in a Faculty, and he could not pursue his favourite
studies--his masters were agitating on his behalf. Balard was clamouring
to have him as an assistant at the Ecole Normale. Biot was appealing to
Baron Thenard. This scientist was then Chairman of the Grand Council of
the Université.[19] He had been a pupil of Vauquelin, a friend of
Laplace, and a collaborator of Gay-Lussac; he had lectured during thirty
years at the Sorbonne, at the Collège de France, and at the Ecole
Polytechnique; he could truthfully boast that he had had 40,000 pupils.
He was, like J. B. Dumas, a born professor. But, whilst Dumas was always
self possessed and dignified in his demeanour, his very smile serious,
Thenard, a native of Burgundy, threw his whole personality into his
work, a broad smile on his beaming face.
He was now (1848) seventy years old, and the memory of his teaching,
the services rendered to industry by his discoveries, the _éclat_ of his
name and titles contrasted with his humble origin, all combined to
render him more than a Chancellor of the University; he was in fact a
sort of Field Marshal of science, and all powerful. Three years
previously he had much scandalized certain red-tape officials by
choosing three very young men--Puiseux, Delesse, and H. Sainte Claire
Deville--as professors for the new Faculty of Science at Besançon. He
had accentuated this authoritative measure by making Sainte Claire
Deville Dean of the Faculty. In the unknown professor of twenty-six, he
had divined the future celebrated scientist.
At the end of the year 1848 Pasteur solicited the place of assistant to
M. Delesse, who was taking a long leave of absence. This would have
brought him near Arbois, besides placing him in a Faculty. He asked for
nothing more. Thenard, who had Biot’s report in his hands, undertook to
transmit to the Minister this modest and natural request. He was opposed
by an unexpected argument--the presentation of assistantships belonged
to each Faculty. This custom was unknown to Pasteur. Thenard was unable
to overcome this routine formality. Pasteur thought that the unanimous
opinion of Thenard, Biot, and Pouillet ought to have prevailed. “I can
practically do nothing here,” he wrote on the sixth of December,
thinking of his interrupted studies. “If I cannot go to Besançon, I
shall go back to Paris as a curator.”
His father, to whom he paid a visit for the new year, persuaded him to
look upon things more calmly, telling him that wisdom repudiated too
much hurry. Louis deferred to his father’s opinion to the extent of
writing, on January 2, 1849, to the Minister of Public Instruction,
begging him to overlook his request. However, the members of the
Institute who had taken up his cause did not intend to be thwarted by
minor difficulties. Pasteur’s letter was hardly posted when he received
an assistantship, not at the Besançon Faculty but at Strasburg, to take
the place of M. Persoz, Professor of Chemistry, who was desirous of
going to Paris.
Pasteur, on his arrival at Strasburg (January 15) was welcomed by the
Professor of Physics, his old school friend, the Franc-Comtois Bertin.
“First of all, you are coming to live with me,” said Bertin gleefully.
“You could not do better; it is a stone’s throw from the Faculté.” By
living with Bertin, Pasteur acquired a companion endowed with a rare
combination of qualities--a quick wit and an affectionate heart. Bertin
was too shrewd to be duped, and a malicious twinkle often lit up his
kindly expression; with one apparently careless word, he would hit the
weak point of the most self satisfied. He loved those who were simple
and true, hence his affection for Pasteur. His smiling philosophy
contrasted with Pasteur’s robust faith and ardent impetuosity. Pasteur
admired, but did not often imitate, the peaceful manner with which
Bertin, affirming that a disappointment often proved to be a blessing in
disguise, accepted things as they came. In order to prove that this was
no paradox, Bertin used to tell what had happened to him in 1839, when
he was mathematical preparation master at the College of Luxeuil. He was
entitled to 200 francs a month, but payment was refused him. This
injustice did not cause him to recriminate, but he quietly tendered his
resignation. He went in for the Ecole Normale examination, entered the
school at the head of the list, and subsequently became Professor of
Physics at the Strasburg Faculty. “If it had not been for my former
disappointment, I should still be at Luxeuil.” He was now perfectly
satisfied, thinking that nothing could be better than to be a Professor
in a Faculty; but this absence of any sort of ambition did not prevent
him from giving his teaching the most scrupulous attention. He prepared
his lessons with extreme care, endeavouring to render them absolutely
clear. He took great personal interest in his pupils, and often helped
them with his advice in the interval between class hours. This excellent
man’s whole life was spent in working for others, and to be useful was
ever to him the greatest satisfaction.
Perhaps Pasteur was stimulated by Bertin’s example to give excessive
importance to minor matters in his first lessons. He writes: “I gave too
much thought to the style of my two first lectures, and they were
anything but good; but I think the subsequent ones were more
satisfactory, and I feel I am improving.” His lectures were well
attended, for the numerous industries of Alsace gave to chemistry quite
a place by itself.
Everything pleased him in Strasburg save its distance from Arbois. He
who could concentrate his thoughts for weeks, for months even, on one
subject, who could become as it were a prisoner of his studies, had
withal an imperious longing for family life. His rooms in Bertin’s house
suited him all the better that they were large enough for him to
entertain one of his relations. His father wrote in one of his letters:
“You say that you will not marry for a long time, that you will ask one
of your sisters to live with you. I could wish it for you and for them,
for neither of them wishes for a greater happiness. Both desire nothing
better than to look after your comfort; you are absolutely everything to
them. One may meet with sisters as good as they are, but certainly with
none better.”
Louis Pasteur’s circle of dear ones was presently enlarged by his
intimacy with another family. The new Rector of the Academy of
Strasburg, M. Laurent, had arrived in October. He was no relation to the
chemist of the same name, and the place he was about to take in
Pasteur’s life was much greater than that held by Auguste Laurent at the
time when they were working together in Balard’s laboratory.
After having begun, in 1812, as preparation master in the then Imperial
College of Louis le Grand, M. Laurent had become, in 1826, head master
of the College of Riom. He found at Riom more tutors than pupils; there
were only three boys in the school! Thanks to M. Laurent, those three
soon became one hundred and thirty-four. From Riom he was sent to
Guéret, then to Saintes, to save a college in imminent danger of
disappearing; there were struggles between the former head master and
the Mayor, the town refused the subsidies, all was confusion. Peace
immediately followed his arrival. “Those who have known him,” wrote M.
Pierron in the _Revue de l’Instruction Publique_, “will not be surprised
at such miracles coming from a man so intelligent and so active, so
clever, amiable, and warm-hearted.” Wherever he was afterwards sent, at
Orleans, Angoulême, Douai, Toulouse, Cahors, he worked the same charm,
born of kindness. At Strasburg, he had made of the Académie a home where
all the Faculty found a simple and cordial welcome. Madame Laurent was a
modest woman who tried to efface herself, but whose exquisite qualities
of heart and mind could not remain hidden. The eldest of her daughters
was married to M. Zevort, whose name became doubly dear to the
Université. The two younger ones, brought up in habits of industry and
unselfishness which seemed natural to them, brightened the home by their
youthful gaiety.
When Pasteur on his arrival called on this family, he had the feeling
that happiness lay there. He had seen at Arbois how, through the daily
difficulties of manual labour, his parents looked at life from an
exalted point of view, appreciating it from that standard of moral
perfection which gives dignity and grandeur to the humblest existence.
In this family--of a higher social position than his own--he again found
the same high ideal, and, with great superiority of education, the same
simple-mindedness. When Pasteur entered for the first time the Laurent
family circle, he immediately felt the delightful impression of being in
a thoroughly congenial atmosphere; a communion of thoughts and feelings
seemed established after the first words, the first looks exchanged
between him and his hosts.
In the evening, at the restaurant where most of the younger professors
dined, he heard others speak of the kindliness and strict justice of the
Rector; and everyone expressed respect for his wonderfully united
family.
At one of M. Laurent’s quiet evening “at homes,” Bertin was saying of
Pasteur, “You do not often meet with such a hard worker; no attraction
ever can take him away from his work.” The attraction now came, however,
and it was such a powerful one that, on February 10, only a fortnight
after his arrival, Pasteur addressed to M. Laurent the following
official letter:--
“SIR,--
“An offer of the greatest importance to me and to your family is
about to be made to you on my behalf; and I feel it my duty to put
you in possession of the following facts, which may have some
weight in determining your acceptance or refusal.
“My father is a tanner in the small town of Arbois in the Jura, my
sisters keep house for him, and assist him with his books, taking
the place of my mother whom we had the misfortune to lose in May
last.
“My family is in easy circumstances, but with no fortune; I do not
value what we possess at more than 50,000 francs, and, as for me, I
have long ago decided to hand over to my sisters the whole of what
should be my share. I have therefore absolutely no fortune. My only
means are good health, some courage, and my position in the
Université.
“I left the Ecole Normale two years ago, an _agrégé_ in physical
science. I have held a Doctor’s degree eighteen months, and I have
presented to the Académie a few works which have been very well
received, especially the last one, upon which a report was made
which I now have the honour to enclose.
“This, Sir, is all my present position. As to the future, unless my
tastes should completely change, I shall give myself up entirely to
chemical research. I hope to return to Paris when I have acquired
some reputation through my scientific labours. M. Biot has often
told me to think seriously about the Institute; perhaps I may do so
in ten or fifteen years’ time, and after assiduous work; but this
is but a dream, and not the motive which makes me love Science for
Science’s sake.
“My father will himself come to Strasburg to make this proposal of
marriage.
“Accept, Sir, the assurance of my profound respect, etc.
“P.S.--I was twenty-six on December 27.”
A definite answer was adjourned for a few weeks. Pasteur, in a letter to
Madame Laurent, wrote, “I am afraid that Mlle. Marie may be influenced
by early impressions, unfavourable to me. There is nothing in me to
attract a young girl’s fancy. But my recollections tell me that those
who have known me very well have loved me very much.”
Of these letters, religiously preserved, fragments like the following
have also been obtained. “All that I beg of you, Mademoiselle (he had
now been authorised to address himself directly to her) is that you will
not judge me too hastily, and therefore misjudge me. Time will show you
that below my cold, shy and unpleasing exterior, there is a heart full
of affection for you!” In another letter, evidently remorseful at
forsaking the laboratory, he says, “I, who did so love my crystals!”
He loved them still, as is proved by an answer from Biot to a proposal
of Pasteur’s. In order to spare the old man’s failing sight, Pasteur had
the ingenious idea of cutting out of pieces of cork, with exquisite
skill, some models of crystalline types greatly enlarged. He had tinted
the edges and faces, and nothing was easier than to recognize their
hemihedral character. “I accept with great pleasure,” wrote Biot on
April 7, “the offer you make me of sending me a small quantity of your
two acids, with models of their crystalline types.” He meant the
righthand tartaric acid and the lefthand tartaric acid, which
Pasteur--not to pronounce too hastily on their identity with ordinary
tartaric acid--then called _dextroracemic_ and _lævoracemic_.
Pasteur wished to go further; he was now beginning to study the
crystallizations of formate of strontian. Comparing them with those of
the paratartrates of soda and ammonia, surprised and uneasy at the
differences he observed, he once exclaimed, “Ah! formate of strontian,
if only I had got you!” to the immense amusement of Bertin, who long
afterwards used to repeat this invocation with mock enthusiasm.
Pasteur was about to send these crystals to Biot, but the latter wrote,
“Keep them until you have thoroughly investigated them.... You can
depend on my wish to serve you in every circumstance when my assistance
can be of any use to you, and also on the great interest with which you
have inspired me.”
Regnault and Senarmont had been invited by Biot to examine the valuable
samples received from Strasburg, the dextroracemic and lævoracemic
acids. Biot wrote to Pasteur, “We might make up our minds to sacrifice a
small portion of the two acids in order to reconstitute the racemic, but
we doubt whether we should be capable of discerning it with certainty by
those crystals when they are formed. You must show it us yourself, when
you come to Paris for the holidays. Whilst arranging my chemical
treasures, I came upon a small quantity of racemic acid which I thought
I had lost. It would be sufficient for the microscopical experiments
that I might eventually have to make. So if the small phial of it that
you saw here would be useful to you, let me know, and I will willingly
send it. In this, as in everything else, you will always find me most
anxious to second you in your labours.”
This period was all happiness. Pasteur’s father and his sister Josephine
came to Strasburg. The proposal of marriage was accepted, the father
returned to Arbois, Josephine staying behind. She remained to keep house
and to share the everyday life of her brother, whom she loved with a
mixture of pride, tenderness and solicitude. In her devoted sisterly
generosity, she resigned herself to the thought that her happy dream
must be of short duration. The wedding was fixed for May 29.
“I believe,” wrote Pasteur to Chappuis, “that I shall be very happy.
Every quality I could wish for in a wife I find in her. You will say,
‘He is in love!’ Yes, but I do not think I exaggerate at all, and my
sister Josephine quite agrees with me.”