Nissl, Franz

   (1860–1919)

   Pioneer of neurohistology, Nissl was born in a small town in the Palatinate (Bavaria), into a schoolteacher’s family. In 1885, he wrote his doctoral dissertation in medicine at Munich University, then began training in psychiatry as an assistant to Professor Bernhard von Gudden (1824–1886), an important brain anatomist. In 1889, Nissl became a staff psychiatrist at the Frankfurt City Aslyum, the direction of which Emil Sioli (1852–1922) had just taken over. Sioli had a strong bent toward biological research and just a few months previously had recruited Alois Alzheimer as well. The scene changed from Frankfurt to Heidelberg in 1895, as Emil Kraepelin persuaded Nissl to come to the university psychiatric clinic for an academic career (Alzheimer would follow in 1902); in 1896, Nissl received his Habilitation at Heidelberg with a study on cell biology. As Kraepelin left Heidelberg for Munich in 1903, Nissl became acting head of the clinic and was appointed director and professor of psychiatry in 1904. In 1918, Nissl finally followed Kraepelin to Munich, to the new German Psychiatric Research Institute (Deutsche Forschungsanstalt für Psychiatrie, or DFA) that Kraepelin had founded in 1917, where Nissl was to lead the histopathology division until his death from a kidney disorder in 1919.

   "Nissl is the founder and creator of the anatomy of mental illness," wrote DFA colleague Walther Spielmeyer (1879–1935) in a biography of Nissl in 1924 (Kirchhoff, II, p. 288). As a medical student, Nissl discovered a procedure for visualizing the cells of the central nervous system that involved, first, fixing the tissues in alcohol, then, staining them with aniline dyes—magenta red and later methylene blue. This caused the nuclei of individual cells to stand out clearly, thus making their study possible in a manner that disclosed internal cell detail. The concept "nerve cell" comes from Nissl, and in contradiction to Theodor Meynert in Vienna, Nissl realized there were different kinds of nerve cells. In 1904, he undertook with Alzheimer the first of an intended series of volumes on the histopathology of the cerebral cortex, the first volume clarifying the pathological changes that take place in neurosyphilis and differentiating it from other kinds of dementias. Nissl had the misfortune to be on the wrong side in the debate over the doctrine of the neuron (opposing the Spanish histologist Santiago Ramón y Cajal [1852–1934], he doubted its existence), and so historically he is remembered mainly for his stains.