“You see, dear Marie, how useful was my journey.”
“Vienna, September 30, 1852. I am not going to Trieste; I shall start for Prague this evening.”
“Prague, October 1, 1852. Here is a startling piece of news. I arrive in Prague; I settle down in the Hôtel d’Angleterre, have lunch, and call on M. Rochleder, Professor of chemistry, so that he may introduce me to the manufacturer. I go to the chemist of the factory, Dr. Rassmann, for whom I had a letter from M. Redtenbacher, his former master. That letter contained all the questions that I usually make to the manufacturers of tartaric acid.
“Dr. Rassmann hardly took time to read the letter; he saw what it dealt with, and said to me: ‘I have long obtained racemic acid. The Paris Pharmaceutical Society offered a prize for whoever manufactured it. It is a product of manufacture; I obtain it with the assistance of tartaric acid.’ I took the chemist’s hand affectionately, and made him repeat what he had said. Then I added: ‘You have made one of the greatest discoveries that it is possible to make in chemistry. Perhaps you do not realise as I do the full importance of it. But allow me to tell you that, with my ideas, I look upon that discovery as impossible. I do not ask for your secret; I shall await the publication of it with the greatest impatience. So that is really true? You take a kilogramme of pure tartaric acid, and with that you make racemic acid?’
“‘Yes,’ he said; ‘but it is still’ ... and as he had some difficulty in expressing himself, I said: ‘It is still surrounded with great difficulties?’
“‘Yes, monsieur.’
“Great heavens! what a discovery! if he had really done what he says! But no; it is impossible. There is an abyss to cross, and chemistry is yet too young.”
Second letter, same date. “M. Rassmann is mistaken.... He has never obtained racemic acid with pure tartaric acid. He does what M. Fikentscher and the Viennese manufacturers do, with slight differences, which confirm the general opinion I expressed in my letter to M. Dumas a few days ago.”
That letter, and also another addressed to Biot, indicated that racemic acid was formed in varying quantities in the mother-liquor, which remained after the purification of crude tartars.
“I can at last,” Pasteur wrote from Leipzig to his wife, “turn my steps again towards France. I want it; I am very weary.”