Barone Justus von Liebig: Frasi in inglese
Familiar Letters on Chemistry, Tr. Blythe, 4th ed., London, 1859, p. 60 as quoted by John Theodore Merz, A History of European Thought in the Nineteenth Century Vol.1 http://books.google.com/books?id=xqwQAAAAYAAJ (1903).
Chemische Briefe (1851) Full Text http://www.archive.org/details/chemischebriefe00liebuoft (quote's translation probably by Martin H. Fischer); quoted in Physical Chemistry in the Service of Medicine (1907), Wolfgang Pauli, p. 71, tr. by Martin H. Fischer. Full Text http://www.archive.org/details/cu31924000951792.