a kidney disease. During World War I he was charged with administering a large military hospital. In 1918 Kraepelin again invited Nissl to accept a research position at the Deutsche Forschungsanstalt für Psychiatrie in Munich. After one year at that position, where he performed research alongside Korbinian Brodmann and Walther Spielmeyer, he died in 1919 of kidney disease. Personal Nissl was of small stature, with poor posture. He had a birthmark on his left face. He never married, and his life revolved entirely around his work. One day, for a practical joke, Nissl (who was an active campaigner against human consumption of alcohol) placed a row of empty beer bottles outside his laboratory and made sure that Kraepelin heard that he could be found lying under his desk, dead drunk. Nissl was a competent pianist. Nazi physician Hugo Spatz (1888–1969) told of his first meeting, when Spatz applied for a position in Nissl's laboratory. Nissl was busy that morning and asked the student to come to his home at twelve. When Spatz came to the house at noon, Nissl was not there, and the housekeeper finally opined that the Professor must have meant twelve midnight, so Spatz returned that night. Nissl was at home then, but Spatz had to wait in the anteroom for half an hour until Nissl had finished the piano sonata that he was playing. The conversation lasted until daybreak. Legacy Nissl was possibly the greatest neuropathologist of his day and also a fine clinician who popularised the use of spinal puncture, which had been introduced by Heinrich Quincke. Nissl also examined the neural connections between the human cortex and thalamic nuclei; he was in the midst of this study at the time of his death. An example of his research philosophy is taken from his 1896 writings: As soon as we agree to see in all mental derangements the clinical expression of definite disease processes in the cortex, we remove the obstacles that make impossible agreement among alienists. Named histology concepts The Nissl method refers to staining of the cell body, and in particular endoplasmic reticulum. This is done by using various basic dyes (e.g. aniline, thionine, or cresyl violet) to stain the negatively charged RNA blue, and is used to highlight important structural features of neurons. The Nissl substance (rough endoplasmic reticulum) appears dark blue due to the staining of ribosomal RNA, giving the cytoplasm