Berlin 26 March 1830
...Liebig is after all extraordinarily diligent, and it is really a pity that he works in the French-German style, like L. Gmelin [Note: Gmelin had been Wöhler's professor in Heidelberg, before he went to Stockholm to work with Berzelius], and as a rule pursues a mass of small new facts, without giving truly conclusive, certain results and complete investigations. He limits himself much too much to minutiae and puts a much greater weight on the correctness of his analyses than on the plausibility of how Nature might have organized the construction of a compound. - By the way, in his letters he is very friendly and likable and we correspond often...
With unchangable respect and friendship
Stockholm 18 June 1830
I have indeed a variety of true curiosities from my laboratory to recount, for example that tartaric acid and racemic acid have exactly the same composition and the same molecular weight, but chemistry must regain its rights when the young wife is pregnant and newlywed chemist has become more a husband than a lover.
Heartfelt greetings to the still unmet Franziska.
Greetings and friendship
Stockholm 9 July 1830
I completely agree with the professor in his judgment that Liebig should have "Quick and dirty" as his motto. His report on hippuric acid and his analysis of malic acid are both so carelessly done that he should have his hand slapped.
Still the chap works hard and has a clear head.
My paper on racemic acid is now in print at the Academy book shop. It is much more interesting than I believed at the beginning of the investigation... Now to come to racemic acid, it has absolutely the same composition and saturation capacity as tartaric acid, they are related to one another as glowing[?] and non-glowing[?] phosphoric acid. Their compounds crystallize with the same number of waters and appear to me to be heteromorphous. I say appear, since I am too poor a crystallographer to judge with certainty when I see things of this sort. Certainly they are chemically different.
Cassel 28. Januar 1835.
Lieber Herr Professor.
Ich gratulire zur Brenz-Traubensäure. Die organische Chemie kann einen jetzt ganz toll
machen. Sie kommt mir wie ein Urwald der Tropenländer vor, voll
der merkwürdigsten Dinge, ein ungeheures Dickicht, ohne Ausgang
und Ende, in das man sich nicht hinein wagen mag.
Von ganzem Herzen
Translation: Congratulations on [discovery of pyruvic acid]. At this time organic chemistry can drive one completely crazy. It seems to me like a primeval tropical jungle, full of the most remarkable things, an amazing thicket, without escape or end, into which one would not dare to enter.