Those 'strange mental constitutions': The theoretical patriotism of Camillo Golgi
Jospeh M. McKEDDIE
In 1873 Camillo Golgi (1843-1926) discovered the riazione nera or black reaction, a silver nitrate impregnation technique that revolutionised neuroanatomical knowledge and legitimated a new field of scientific endeavour - neurohistology. On the basis of results obtained with the new method Golgi reasoned that nerve cells formed an anastomotic reticulum defined by axo-axonic continuity. At the time the idea of a nerve-net was not without support but became increasingly scrutinised with improvements in methods of fixation, embedding and staining of neurological tissue using the Golgi method. Led most notably by Wilhelm His (1831-1904) and Santiago Ramon y Cajal (1852-1934), the initial capriciousness of the black reaction gradually yielded to a new perspective on the nature of cellular relations which was to manifest in a competing theory, the neuron doctrine. This theory, which held the cerebrum to consist of anatomically distinct cellular units, or neurons, triggered a protracted debate between the so-called "reticularists" and "neuronists" during the late nineteenth and early twentieth centuries that was highly polemical and which attracted many leading figures of anatomy, pathology and histology. A decisive moment in the history of the neuron doctrine came in 1888 when Cajal first applied his modified staining technique to embryonic neural tissue. By allowing Cajal to trace the prolongation of Deiters and protoplasmic expansions in their entirety during embryogenesis, this novel methodological approach revealed the free termination of axonal arborisations. Coupled with subsequent research into the nature of peripheral nerve regeneration by Cajal and Ross Harrison (1870-1959) among others, these investigations did much to empirically validate the neuron doctrine. Today the idea of the independence of the nerve cell represents a fundamental tenet of the neurological sciences. However, throughout his intellectual life Golgi, paradoxically, never accepted the neuron doctrine favouring instead the existence of the nerve-net. The reasons are here analysed.
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Pavia, Italy, 2006