(b. Breslau, Germany [now Wrocław, Poland], 7 December 1864; d. Tübingen, Germany, 14 December 1949)
microscopic anatomy, microtechnique.
Both of Heidenhain’s parents were members of families which included well-known physicians and university professors. His father was the renowned physiologist Rudolf Heidenhain, who taught for thirty-eight years at the University of Breslau and was himself the son of a prominent Prussian physician; his mother, Fanny Volkmann, was the daughter of the anatomist and physiologist Alfred Volkmann, professor at the University of Halle, where Rudolf Heidenhain had studied. Four of Heidenhain’s uncles were physicians, and his brother was the well-known surgeon Lothar Heidenhain, who taught and practiced in Breslau.
Heidenhain displayed interest in the natural sciences, especially geology and paleontology, while he was still a student at the Gymnasium in Breslau. Following graduation he studied biology at the University of Breslau and later in Würzburg. He then studied medicine in Freiburg im Breisgau, where he obtained the M.D. in 1890. Instead of practicing medicine, he became an assistant to the anatomist Rudolf Kölliker at Würzburg, and from there he moved to a teaching position at the University of Tübingen in 1899. He remained at Tübingen for the rest of his life and assumed the post of professor of anatomy in 1917, following the death of August von Frorieps. While in Würzburg, Heidenhain married Anna Hesse, the daughter of a lawyer. The couple had three sons, all of whom they survived.
In the course of his professional life as a teacher and researcher, which spanned some fifty years, Heidenhain produced about 100 publications, including several books. He taught microscopy, embryology, and anatomy. His principal areas of research were microscopic anatomy (for example, the structure of heart and skeletal muscle, taste buds, salivary glands, and the thyroid, as well as the comparative anatomy and developmental history of the kidney) and the development of microtechnique. It is owing to his activity in the latter field that Heidenhain’s name is known to all present-day histologists and cytologists. In 1891 he discovered the still widely used iron-hematoxylin staining method which bears his name. Subsequently he invented the mercuric chloride method of tissue fixation and pioneered the use of aniline dyes for the staining of tissues. Heidenhain was not satisfied with the application of then established methods of microscopic preparation to his particular research problems. Rüdiger von Volkmann, in an article honoring Heidenhain’s seventieth birthday and dealing with his accomplishments in microtechnique, records the following quotation by Heidenhain: “I have always made up my own methods, just as I needed them.”
Heidenhain’s magnum opus is the two-volume cytology text Plasma und Zelle (1907–1911), which he had been invited to contribute to Heinrich von Bardeleben’s Handbuch der Anatomie des Menschen. In this work Heidenhain attempted to develop a synthetic theory of morphogenesis based on a hierarchic arrangement of levels of organization, starting with hypothetical subcellular “protomeres” and ascending to macroscopic structures, the various levels being subject to and integrated by one set of natural laws. Although stimulated by the writings of the philosopher of biology Hans Driesch, Heidenhain rejected Driesch’s metaphysical speculations and attempted to explain the general laws which govern living material on the basis of microscopic findings and researches into the developmental history of organisms and their parts. Heidenhain’s efforts in the area of theoretical biology were appreciated by his contemporary Wilhelm Roux and by a subsequent generation of scientists represented by, among others, the anatomists Alfred Benninghoff, Hermann Bautzmann, and Walther Jacobj.
Heidenhain was a pleasant and congenial man, well liked by his colleagues, assistants, and students. His was not a one-track mind devoted solely to the pursuit of scientific knowledge; it was open also to other cultural concerns. He appreciated and collected old German wood carvings and potteries.
A complete bibliography of Heidenhain’s writings has been published by Walther Jacobj in Anatomischer Anzeiger, 99 (1952–1953), 89–94.
An appreciation of Heidenhain’s accomplishments in microtechnique was published by Rüdiger von Volkmann in Zeitschrift für Mikroskopie, 51 (1934), 309–315. Heidenhain’s student Jacobj published an obituary in Anatomischer Anzeiger, 99 (1952–1953), 80–89. A short biographical note on Heidenhain can be found in Neue deutsche Biographie, VIII (1969), 247.