(b. Berlin, Germany, 25 July 1847; d. Funchal, Madeira, 20 July 1888)
Langerhans’ father, for whom he was named, was a well-known physician in Berlin; and two younger stepbrothers were also physicians. One of them, Robert (1859-1904), was an assistant to Virchow and later became professor of pathology. Langerhans attended the Gymnasium zum Grauen Kloster in Berlin and graduated at the age of sixteen. From 1856 to 1866 he studied medicine at the University of Jena, where he was much impressed by Haeckel and Gegenbaur. He continued his medical studies in Berlin under K. Bardeleben, E. du Bois-Reymond, R. Virchow, J. Cohnheim, and F. T. von Frerichs. In 1869 he graduated M.D. At Berlin he was particularly influenced by Virchow and Cohnheim, and he became later a close friend of Virchow’s. His first important research was done in Virchow’s laboratory, where he discovered the cell islands of the pancreas named after him.
In 1870 Langerhans accompanied the geographer Heinrich Kiepert on an expedition to Egypt and Palestine. During the Franco-Prussian War he joined the German army as a physician and worked in a military hospital. After the conclusion of peace he went for a short while to Leipzig to see Ludwig’s famous physiological institute and the obstetrical clinics of K. S. F. Crédé. In 1871 he was offered the position of prosector in pathology at the University of Freiburg im Breisgau, where he also became Privatdozent in the same year and, later, associate professor. In 1874 tuberculosis of the lung compelled Langerhans to interrupt his academic career. Attempts at cure in Switzerland, Italy, and Germany failed; and in 1875 he settled in Madeira. Its mild climate led to an improvement in his health. In Madeira he later practiced medicine in the capital, Funchal, where he died of a kidney infection.
Langerhans’ main scientific achievements consist in his studies of human and animal microscopical anatomy. In this field he was among the first successful investigators to explore the new area of research with novel methods and staining techniques. Langerhans made his first scientific contributions as a medical student in Virchow’s laboratory, under the guidance of Virchow and especially of Cohnheim. In 1868 he published a paper on the innervation of the skin; he had used gold chloride as a stain. He was able to show nerve endings in the Malpighian layer of the epidermis and described characteristic oblong bodies with branching processes in the Malpighian layer (later called Langerhns’ cells). He believed that these bodies were probably nerve cells, but he did not exclude the possibility that they might be pigment cells (later called dendritic cells).
In his inaugural dissertation (1869) Langerhans immortalized his name by his discovery of characteristic cell islands in the pancreas named for him. The investigations for this work, “Beiträge zur mikroskopischen Anatomie der Bauchspeicheldrüse,” were conducted in Virchow’s pathology laboratory. The paper presented the first careful and detailed description of the microscopic structure of the pancreas.
Langerhans examined mainly the pancreas of rabbits. He studied fresh tissue and even sought to make microscopic observations of pancreatic tissue in the living animal. His main results were obtained through chemical fixation and maceration. Langerhans injected the pancreatic duct with Berlin blue in order to show the branching and the structure of the excretory system. Examining portions of the fresh gland, he distinguished thre zones in the secreting cells: an apical granular zone. In macerated pancreatic tissue he differentiated varous types of cells, including small, irregularly ploygonal cells without granuels. These cells formed numerous spots scattered through the parenchyma of the gland measuring 0.1-0.24 mm. in diameter. Langerhans refrained from making any hypothesist as to the nature and significance of these cells. In 1893 the French histologist G. E. Laguesse named these cell spots “îlots de Langerhanns” the insulin-secreting function of these cells was established later.
Another important contribution, make with F. A. Hoffmann in Virchow’s laboratory, dealt with the macrophage system. Langerhans and Hoffmann studied the intravital storage of cinnabar injected intravenously in rabbits and guinea pigs. After the injection they sought the presence of cinnabar in the blood and all the organs except the spleen. They were able to show that cinnabar was taken up by white blood corpuscles but never by the red. They also demonstrated the deposit of cinnabar in fixed cells of the bone marrow, in the capillary system, and in the connective tissue of the liver. This was one of the pioneer investigations that later led to Aschoff’s concept of the reticuloendothelial system.
In 1873 Langerhans studied the structure of the skin and its innervation, staining the preparations with osmic acid and picrocarmine. He observed the nerve fibers branching in the interior of Meissner’s corpuscles and described the oblong cells lying transversely in these corpuscles. In the report on this study Langerhans described his discovery of the granular cells in the exterior portion of the Malpighian layer (Langerhans’ layer, stratum granuloum). In 1873 and 1874 Langerhans examined the microscopic structure of the cardiac muscle fibers in vertebrates and of the accessory genital glands of man. One of his last extensive histological papers (1876) was dedicated to the anatomy of the amphoxus.
During his trip to Palestine, Langerhans, stimulated by Virchow’s interest in anthropology, made skull measurements and anthropological observations of the population of Palestine. In the last decade of his life, while practicing medicine on Madeira, Langerhans studied the etiology of tuberculosis and cautiously supported Virchow’s dualistic view, which differentiated phthisis from tuberculosis. During that time he also published a handbook on Madeira dealing with the climatic and curative properties of that island.
I. Original Works. A comprehensive list of Langerhans’ anatomical works was compiled by K. Bardeleben, in Anatomischer Anzeiger, 3 (1888), 850-851. A partial list is by H. Morrison, in Bulletin of the Institute of the History of Medicine, 5 (1937), 266
On microscopic anatomy see “Ueber die Nerven der menschlichen Haut,” in Virchows Archiv für pathologische Anatomie. 44 (1868), 325-337; “Zur pathologischen Anatomie der Taskoumlrper,” ibid., 45 (1869), 413-417; “Ueber den Verbleib des in die Circulation eingeführten Zinnobers,” ibid., 48 (1869), 303-325; “Beiträumlge zur mikroskopischen Anatomie der Bauchspeicheldrüse,” his inaugural dissertation (Berlin, 1869), repr., with English trans. and introductory essay by H. Morrison in Bulletin of the Institute of the History of Medicine, 5 (1937), 259-297; “Ein Beitrag zur Anatomie der sympathischen Ganglienzellen,” his Habilitationsschrift (Freiburg im Breisgau, 1871); “Zur Histologie des Herzens,” in Virchows Archiv für pathologische Anatomie, 58 (1873), 65-83; “Ueber mehrschinchtige Epithelien,” ibid., 83-92; “Ueber die accessorischen Drüsen der Geschlechtsorgane,” ibid., 61 (1874), 208-228; “Ueber Tastkörperchen und Rete Malpighi,” in Archive für mikroskopische Anatomie, 9 (1873), 730-744.
Zoological works include “Zur Entwicklung der Gastropoda opisthobranchia,” in Zeitschrift für wissenschaftliche Zoologie, 23 (1873), 171-179; and “Zur Anatomie des Amphoxus lanceolatus,” in Archive für mikroskopische Anatomie, 12 (1876), 290-348.
A work in pathology is “Zur Aetiologie der Phthise,” in Virchows Archiv für pathologische Anatomie, 97 (1884), 289-306.
On anthropology see “Ueber die heutigen Bewohner des heiligen Landes,” in Archive für Anthropologie, 6 (1873), 39-58, 201-212; and Handbuch für Madeira (Berlin, 1885).
II. Secondary Literature. The most detailed biographical sketch of Langerhans and evaluation of his work is H. Morrison, in Bulletin of the Institute of the History of Medicine, 5 (1937), 259-267, with portrait. See also K. Bardeleben, “Paul Langerhans,” in Anatomischer Anzeiger, 3 (1888), 850; W. R. Campbell, “Paul Langerhans 1847-1888,” in Canadian Medical Association Journal, 79 (1958), 855-856; and G. Wolff, “Beiträge berühmter Studenten zur Erforschung des Zuckerstoffwechsels,” in Münchener medizinische Wochenschrift, 102 (1960), 1203-1208.