At the end of the school year, 1843, he took at the Lycée St. Louis two “Accessits,”[8] and one first prize in physics, and at the “Concours Général”[9] a sixth “Accessit” in physics. He was admitted fourth on the list to the Ecole Normale. He then wrote from Arbois to M. Barbet, telling him that on his half-holidays he would give some lessons at the school of the Impasse des Feuillantines as a small token of his gratitude for past kindness. “My dear Pasteur,” answered M. Barbet, “I accept with pleasure the offer you have made me to give to my school some of the leisure that you will have during your stay at the Ecole Normale. It will indeed be a means of frequent and intimate intercourse between us, in which we shall both find much advantage.”
Pasteur was in such a hurry to enter the Ecole Normale that he arrived in Paris some days before the other students. He solicited permission to come in as another might have begged permission to come out. He was readily allowed to sleep in the empty dormitory. His first visit was to M. Barbet. The Thursday half-holiday, usually from one to seven, was now from one to eight. “There is nothing more simple,” he said, “than to come regularly at six o’clock on Thursdays and give the schoolboys a physical science class.”
“I am very pleased,” wrote his father, “that you are giving lessons at M. Barbet’s. He has been so kind to us that I was anxious that you should show him some gratitude; be therefore always most obliging towards him. You should do so, not only for your own sake, but for others; it will encourage him to show the same kindness to other studious young men, whose future might depend upon it.”
Generosity, self-sacrifice, kindliness even to unknown strangers, cost not the least effort to the father and son, but seemed to them the most natural thing possible. Just as their little house at Arbois was transformed by a ray of the ideal, the broken down walls of the old Ecole Normale—then a sort of annexe of the Louis Le Grand college, and looking, said Jules Simon, like an old hospital or barracks—reflected within them the ideas and sentiments which inspire useful lives. Joseph Pasteur wrote (Nov. 18, 1843): “The details you give me on the way your work is directed please me very much; everything seems organized so as to produce distinguished scholars. Honour be to those who founded this School.” Only one thing troubled him, he mentioned it in every letter. “You know how we worry about your health; you do work so immoderately. Are you not injuring your eyesight by so much night work? Your ambition ought to be satisfied now that you have reached your present position!” He also wrote to Chappuis: “Do tell Louis not to work so much; it is not good to strain one’s brain. That is not the way to succeed but to compromise one’s health.” And with some little irony as to the cogitations of Chappuis the philosopher: “Believe me, you are but poor philosophers if you do not know that one can be happy even as a poor professor in Arbois College.”
Another letter, December, 1843, to his son this time: “Tell Chappuis that I have bottled some 1834 bought on purpose to drink the health of the Ecole Normale during the next holidays. There is more wit in those 100 litres than in all the books on philosophy in the world; but, as to mathematical formulæ, there are none, I believe. Mind you tell him that we shall drink the first bottle with him. Remain two good friends.”
Pasteur’s letters during this first period at the Normale have been lost, but his biography continues without a break, thanks to the letters of his father. “Tell us always about your studies, about your doings at Barbet’s. Do you still attend M. Pouillet’s lectures, or do you find that one science hampers the other? I should think not; on the contrary, one should be a help to the other.” This observation should be interesting to a student of heredity; the idea casually mentioned by the father was to receive a vivid demonstration in the life-work of the son.
CHAPTER II
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.