At the end of the nineteenth century an oft-quoted sentence circulated among critics of Matthias Jakob Schleiden's cell theory and was usually attributed to the German botanist and mycologist Anton de Bary (1831–88): ‘Die Pflanze bildet Zellen, nicht die Zelle bildet Pflanzen’ (‘The plant forms cells; the cell does not form plants’). Although in the beginning the aphorism was employed against the widespread practice (since the development of Schleiden's cell theory) of starting textbooks on botany with the study of cells rather than of whole plants, its use was quickly extended. In the hands of embryologists and physiologists, the aphorism acquired a polemic charge against the mechanistic interpretation of organic development and indicated a holistic way to conceive the process of morphogenesis. In Europe and the United States the sentence spread and was repeated as a refrain by many first-rank zoologists working in old or emerging institutions. One of the most convinced advocates of de Bary's idea was the influential nineteenth-century American biologist Charles Otis Whitman (1842–1910). Indeed, in 1893 Whitman published an article that inspired many young biologists who were critical of mechanistic and ‘elementalist’ interpretations of living phenomena. The article, titled ‘The Inadequacy of the Cellular Theory of Development’, began by criticizing Schleiden's cell theory.