Only one textual passage comes to disrupt the tireless repetition of the graphic structure: an excerpt from the journal of the German chemist August Kekule
, who, while living in Ghent, supposedly discovered the annular structure of benzene after a vision of a snake biting its own tail appeared to him during a day-dream.
In 1858 Friedrich August Kekule
introduced his valence bond theory of chemical combination that he used in 1865 when he suggested a chemical structure for benzene.
For example, Louis Pasteur (1822-1895), who initially wanted to be a professor of fine arts, attended lectures by Dumas, who encouraged him to do research in chemistry ; and Friedrich August Kekule
(1829-1896), a pupil of Liebig, in Giessen, went to Paris to follow courses given by Dumas .