“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.”