The first illustrations of neurons by Camillo Golgi

Abstract

In 1906, the sixth Nobel Prize in Physiology or Medicine was awarded to Camillo Golgi (1843–1926) and Santiago Ramon y Cajal (1852–1934) in recognition of their work on the structure of the nervous system. The name of Golgi is eponymous with the cytoplasmic organelle that he discovered (the Golgi apparatus) and a type of cerebellar cell (the Golgi cells). But Golgi’s most impressive contribution was perhaps his method of histological silver-staining, the black reaction (la reazione nera), described in 1873 at the Abbiategrasso Hospital in Milan, Italy. This method initiated a new era in the description of the microscopic anatomy of the nervous system. Golgi studied at the University of Pavia, Italy, which was famous for its school of anatomy, led by Giovanni Battista Morgagni and Antonio Scarpa. He became interested in the study of nervous system cells through his teacher and friend Giulio Bizzozero, a pathologist who had been a student of Rudolf Virchow at the Charite Hospital at the University of Medicine in Berlin, Germany. Golgi used the black reaction to study the cerebellum, the olfactory bulb, the hippocampus, and the spinal cord. His fi ndings raised fundamental questions about the structure–function relationships in neuronal circuits. Golgi championed the so-called reticular theory, which envisaged the nervous system as a single, continuous network. The notion was challenged by Ramon y Cajal’s widely accepted neuron theory. Between 1875 and 1885, Golgi published eight masterpieces entitled “Sulla fina anatomia degli organi centrali del sistema nervoso”, with 24 colour plates drawn by himself, in the Rivista sperimentale di Freniatria e di medicina legale, a specialist Italian journal. These articles describe some of the most important work on the structure of the nervous system published at that time. They contain much better plates than those included in the books that reprinted these articles in 1886 and 1894 (a German translation), and again in Golgi’s Opera Omnia in 1903. At the time, reprinting preserved neither the beauty of the original plates nor the details of fine anatomical nervous structures. More than a century after its initial publication, Golgi’s work is always of considerable historical scientific interest. We had the opportunity to find in a small bookstore in Rome, Italy, all the issues of Rivista sperimentale di Freniatria e di medicina legale with the eight articles by Golgi and the original coloured plates. These plates are extremely rare, as very few copies of these issues were printed. The figure displays one of these beautiful plates, and the remainder are presented in the appendix. The plate reproduced here illustrates the connections between multiple Golgi cells in a sample of cerebellar convolution (vertical section) from a neonatal cat. As translated from Golgi’s original legend, “the design is particularly intended to show the shape, arrangement, ramification rules, positions, and links between ganglionic cells existing within the granular layer”. Golgi’s histological samples were thick, and such thickness can affect the functional description of neurons and fibres. Cells were therefore drawn from slightly different microscopic depths of fi eld. Axons and dendrites are presented in a single image, although extending across multiple layers. Indeed, Golgi’s drawing was specifically made to show shapes, ramification laws, dispositions, localisation, and relationships of the large ganglionic cells of the granular layer. Protoplasmic prolongations branch dichotomously in a very different way than do those of Purkinje cells. The most distal extensions of the branches often reach the molecular layer peripheral limit. Figure: Plate VIII—The spatial relationships between multiple Golgi cells