Editing Camillo Golgi (section)

===Black reaction or Golgi's staining===
[[File:Golgi's drawing of nervous system.gif|thumb|The first illustration by Golgi of the nervous system. Vertical section of the olfactory bulb of a dog (in 1875).]]
The [[Central nervous system]] was difficult to study during Golgi's time because the cells were hard to identify. The available [[Staining (biology)|tissue staining techniques]] were useless for studying [[nervous tissue]]. While working as chief medical officer at the Hospital of the Chronically Ill, he experimented with metal impregnation of nervous tissue, using mainly [[silver]] ([[silver staining]]). In early 1873, he discovered a method of staining nervous tissue that would stain a limited number of cells at random in their entirety. He first treated the tissue with potassium dichromate to harden it, and then with silver nitrate. Under the microscope, the outline of the neuron became distinct from the surrounding tissue and cells. The silver chromate precipitate, as a reaction product, selectively stains only some cellular components randomly, sparing other cell parts. The silver chromate particles create a stark black deposit on the [[Soma (biology)|soma]] (nerve cell body) as well as on the [[axon]] and all [[dendrites]], providing an exceedingly clear and well-contrasted picture of [[neuron]] against a yellow background. This makes it easier to trace the structure of the nerve cells in the brain for the first time.<ref name="benti"/> Since cells are selective stained in black, he called the process ''la reazione nera'' ("the black reaction"), but today it is called [[Golgi's method]] or the Golgi stain.<ref>{{cite journal|last1=Chu|first1=NS|title=[Centennial of the nobel prize for Golgi and Cajal—founding of modern neuroscience and irony of discovery]|journal=Acta Neurologica Taiwanica|date=2006|volume=15|issue=3|pages=217–222|pmid=16995603}}</ref> On 16 February 1873, he wrote to his friend Niccolò Manfredi:
{{Blockquote|I am delighted that I have found a new reaction to demonstrate, even to the blind, the structure of the interstitial stroma of the cerebral cortex.}}
His discovery was published in the ''Gazzeta Medica Italiani'' on 2 August 1873.<ref>{{cite journal|last1=DeFelipe|first1=Javier|title=The dendritic spine story: an intriguing process of discovery|journal=Frontiers in Neuroanatomy|date=2015|volume=9|page=14|doi=10.3389/fnana.2015.00014|pmid=25798090|pmc=4350409|doi-access=free }}</ref>