1884.] On the Chemical Work of Wohler. 479 



liberal thought in science, and the words with which Wohler closes 

 his account of the molecular transformation of ammonium cyanate — 

 a body of purely inorganic origin— into urea, a substance which of 

 all that might be named is the most characteristic of the action of the 

 so-called vital force, are full of meaning. "This unexpected result," 

 he says, " is a remarkable fact in so far as it presents an example of the 

 artificial formation of an organic body, and indeed one of animal origin 

 out of inorganic materials." 



At about the time that Wohler made this great discovery he became 

 acquainted with Liebig. When Wohler was at Stockholm, think- 

 ing and working on cyanic acid, Liebig was in Paris engaged with 

 Gay Lussac on the study of the metallic compounds of fulminic 

 acid. The result of the investigations was to show that the explo- 

 sive fulminic acid and the innocuous cyanic acid were of identical 

 composition. The idea that bodies could exist of identical ultimate 

 composition and yet possess essentially different properties was then 

 new to science. Berzelius, the great chemical law-giver of his time, 

 scouted the notion as absurd, until the discovery by his pupil Wohler 

 of the molecular transformation of ammonium cyanate into urea forced 

 him to realise the fact, and to coin for us the word isomerism by which 

 that fact is denoted. On the proposition of Wohler, the two chemists 

 engaged to work together. " Es muss wirklich ein boser Diimon sein," 

 wrote Wohler to Liebig, "der uns immer wieder unvermerkt mit 

 unsern Arbeiten in Collision bringen und das chemische Publicum 

 glauben machen will, wir suchten dergleichen Zankapfel als Gegner 

 absichtlich auf. Ich denke aber, es soil ihm nicht gelingen. Wenn 

 Sie Lust dazu haben, so konnen wir uns den Spass machen, irgend eine 

 chemische Arbeit gemeinschaftlich vorzunehmen, um das Resultat 

 unter unserm gemeinschaftlichen Namen bekannt zu machen . . . Ich 

 iiberlasse die Wahl des Gegenstandes ganz Ihnen." 



Their first work in common was on mellitic acid. Shortly after 

 its appearance, Wohler and Liebig undertook a joint investigation on 

 cyanuric acid, in the course of which they observed the extraordinary 

 transformation of that acid into cyanic acid and the reconversion of 

 the cyanic acid into cyanuric acid — one of the most remarkable 

 instances of polymeric rearrangement known to the chemist. 



In 1831 Wohler was called from Berlin to Cassel, and for some little 

 time he was wholly engaged in the planning and erection of his new 

 laboratory at the Gewerbe Schule in that town. In the spring of the 

 following year, he proposed to Liebig to attempt to clear up the con- 

 fusion respecting the nature and relations of the essential oil of bitter 

 almonds. This, as a piece of work, was perhaps their masterpiece. 

 The investigation on the radicle of benzoic acid will ever remain one 

 of the greatest achievements in the history of organic chemistry. It 

 was full of facts, and rich in the promise of new material. The 

 immediate effect of the paper was to establish the doctrine of organic 

 radicles by demonstrating the existence of groups of bodies which had 



