Though many sources mention 1859 as Zeidler's year of birth, this would make him a mere 14 years old at the time of his dissertation in 1873. The 1859 birth year was used by Joseph S. Fruton, in his Contrasts in scientific style: research groups in the chemical and biochemical sciences, Memoirs of the American Philosophical Society, Vol 191, 1990, p. 373, as well as by Gerhard Oberkofler in Leopold Ruzicka, 1887–1976: schweizer Chemiker und Humanist aus Altösterreich, p. 44. The latter even has him quit his pharmacy studies at the Vienna University in 1872 (at the apparent age of 12/13) to move to Strassburg. However, Materialien zur Geschichte der Apotheken und Apotheker Niederösterreichs gives his year of birth as 1850; furthermore, his obituary at Oesterreichische Chemiker–Zeitung in 1911 states that Zeidler was 61 years at the time of his death, placing his birth around 1850 (in reality, Zeidler died 2 months shy of his 61st birthday).
Obituary of Franz Zeidler Jr in Zeitschrift des allgemeinen Oesterreichischen Apotheker-Vereines, Volume 39, 1901
