In 1773, Hilaire Rouelle discovered urea. In 1828, the German chemist Friedrich Weiler first used inorganic material ammonium cyanate (NH4CNO, an inorganic compound that can be obtained from the reaction of ammonium chloride and silver cyanate) and ammonium sulfate to synthesize urea. Originally he intended to synthesize ammonium cyanate but got urea. The synthesis of urea unveiled the prelude to synthetic organics. Thus, it was proved that the vitality theory was wrong and actually opened up organic chemistry (the vitality theory considered that inorganic matter and organic matter have fundamental differences, so inorganic matter cannot be transformed into organic matter, and organic compounds can only be made by living cells in a special kind. Power - the role of vitality, artificial synthesis is impossible. Mammals, amphibians and some fish contain urea in urine; birds and reptiles discharge uric acid because of the use of less water for nitrogen metabolism.) .
