Joseph von Gerlach (1820-1896).

Abstract

Joseph von Gerlach was born 5 years after the end of the Napoleonic wars in Europe, in 1820, in the southwestern German city of Mainz within the grand duchy of HessianDarmstadt. He was the son of a dyer and received his medical training at the universities of Wuerzburg, Munich, and Berlin, before continuing his postgraduate training in Paris [1]. Gerlach joined a growing community of expatriated scientists and intellectuals in the French capital, who during the time of the bourgeois revolutions had found personal refuge and new careers ‘‘on the left side of the Rhine’’ [2]. The opportunities of the Parisian clinical environment were emphasized in many journal articles and in contemporary travel literature, featuring prominent naturalists and physicians such as Carl Vogt (1817–1895), Moritz Schiff (1823–1896), and Johann Heyfelder (1798–1869) from Erlangen, University of Tuebingen’s Hubert von Luschka (1820–1875), or Friedrich von Frerichs (1819–1885) from Berlin. In Paris, von Gerlach also appreciated the latest developments in the sciences and the arts, which he soon integrated into his own research, such as the use of carmine and gold staining in neurohistological fixed preparations of the brain and spinal cord [3] (Fig. 1). After his return to Germany he first worked as a general practitioner in Mainz, a period during which he actively continued his neuroanatomical research. In 1850, von Gerlach was offered a professorship of anatomy and physiology in the nearby Franconian University of Erlangen, which strongly expanded during this period. He continued his interests in microphotography which he developed for the practical use in morphological research, while also publishing his well-received textbook Photography as an Auxiliary Tool for Microscopic Research, 1863 in Leipzig. It was one of the first German-speaking microphotographical textbooks about the new imaging methodology in histological practice. Von Gerlach has even been referred to as a ‘‘father of microphotography’’ in the German-speaking scientific world, and as an important pendant to the bacteriologist Alfred Donne (1801–1878) in France [4]. The introduction of microphotography, however, did not go uncontested, since many of von Gerlach’s peers attacked the interpretative character of the new ‘‘photograms’’ (Daguerrotypes) and the subjective steps which had to be taken in the chemical development of the images. Following the continued experiences with this new medium among the neurohistologists, critique was raised about the reliability of the apparatuses, operational steps, and modes of practical manipulation through the photographer. This discussion over the new visualization method in many ways resembled previous discourses about the subjectivity of anatomical hand-drawings of brain slides [5]. With each step of the image generation and interpretation, the visual perception itself had to be adjusted like the technical instruments themselves. The production and storage of the photographic plates, the exposure to light, the process of photographic development, and the following picture interpretation, etc. all determined the visual perception of the microphotographically produced images of nervous tissue. In his scientific self-defense to critical peer microscopists, von Gerlach therefore developed crucial auxiliary arguments which displayed many facets of the epistemological discourse of nineteenth-century medical research, & Frank W. Stahnisch fwstahni@ucalgary.ca