Camillo Golgi (1843–1926) was a doctor and researcher who discovered a new technique for staining tissue samples
Camillo Golgi was born in the small village of Corteno, near Brescia, in northern Italy. He was the son of the district medical officer and he followed in his father’s footsteps, studying medicine at the University of Pavia.
In Pavia, Golgi worked in the laboratory of Giulio Bizzozero. The young Professor Bizzozero introduced Golgi to histology (the study of the microscopic structure of tissue and cells), to experimental research, and also to his future wife, Bizzozero’s niece Donna Lina Aletti, whom Golgi married in 1877.
In 1872 Golgi took up the post of chief medical officer at a hospital for the chronically ill at Abbiategrasso. While he was there he set up a laboratory in one of the hospital’s kitchens so he could carry out research into the central nervous system – but it was not what he discovered but how he did it that earned Golgi his place in the history books. To examine the structure of the nervous system, Golgi developed a new technique for staining individual cells so that they became clearly visible under the microscope.
First, he hardened a sample of tissue in potassium dichromate. He then immersed the sample in silver nitrate solution. The resulting reaction between potassium dichromate and silver nitrate caused deposits of silver chromate to form on the cell membrane, staining it black. Golgi’s method is unique because only a few random individual cells are left stained, so they stand out from the other, unstained, cells. These stained cells appear as dark silhouettes against a yellow background.
Golgi’s technique was the first to reveal the delicate extensions of neural cells, the axon and the dendrites. He called his method the ‘la reazione nera’ (‘the black reaction’). Today it is known as ‘Golgi’s method’ or the ‘Golgi stain’.
The ‘black reaction’ was key to the development of neuroscience as it led to the establishment of the neuron doctrine, the discovery that the nervous system is made up of discrete neural cells. Golgi himself did not believe this theory. Like many scientists in the 19th century, he favoured a different theory called the ‘reticular theory’.
The reticular theory, first proposed by German histologist Joseph von Gerlach, stated that the nervous system consisted of a single continuous network called the reticulum. Although his method would in the future help to disprove the reticular theory, Golgi initially believed that his discoveries proved the existence of a reticulum structure. He wrote at the time: “I was confronted by the concrete fact; this was the existence of the formation which I have called the diffuse nerve network.”
Despite his mistaken loyalty to the reticular theory, Golgi’s work was invaluable. One of the most famous beneficiaries of his work was the Spanish histologist Santiago Ramón y Cajal (read more on Cajal), who used Golgi’s method to establish that the neuron is the fundamental structural unit of the nervous system.
Although they did not work together – and, in fact, held conflicting views – in 1906 the two men were jointly awarded the Nobel Prize in Physiology or Medicine “in recognition of their work on the structure of the nervous system”. Golgi was the first Italian to receive the prize.Lead image:
Wellcome Library, London
Questions for discussion
- Golgi also made discoveries in other areas of biology – can you find out what they were? Go to the websites listed below to read more about his life and work.
- The reticular theory was disproved and was replaced by the neuron doctrine. Can you think of another theory about the brain or the human body that turned out to be wrong?