The war of images

    1906 was the first time a Nobel Prize was awarded to two scientists. The prize for medicine was shared by the Spanish Santiago Ramon y Cajal and the Italian Camillo Golgi who earned it for their groundbreaking research on the structure of the nervous system. Although they worked in the same field of science, the first time they ever met was at the award ceremony in Stockholm.

    Traditionally, each laureate is given an honorary lecture in which he can describe his work in detail. Golgi’s lecture was one day before Cajal’s and some controversy between the two was to be expected. Even though both were doing research on the anatomy of nerves, each of them had his own theory on how the nervous system was built and how it functioned. Despite the fact that both of the scientists were highly accomplished professors, one could sense a strongly skeptical attitude towards some of the main conclusions each supported during their presentations.

    As a child, he blew up his neighbor’s door with a cannon

    In the early years of his life, Santiago Ramon y Cajal showed little promise of becoming a distinguished scientist. He was a very troublesome child and was expelled from several schools for his low grades and misbehavior. Once, when he was eleven, he even ended up in jail: During summer holidays, he and his gang, of which he was also the leader, had constructed a live cannon from scrap metal. Naturally, the youngsters had to test their artillery piece and the neighbor’s new garden door was the perfect target artillery piece.

    After the explosion, which was devastating, the neighbor complained to the mayor who sent an officer to bring the eleven-year-old Santiago into custody. Of course, his father was furious and insisted on making this outrage his son’s final lesson. Santiago had to spend four days inside a smelly, dirty cell on nothing but bread and water. His mother persuaded the guard to let her sneak in some food, but her son still had to spend those nights and days in solitude.

    The severe punishment was obviously not enough to make him mend his ways, however. He and his gang constructed yet another cannon, only for it to explode while it was being tested. They continued experimenting with other ballistic methods which could have very easily ended with a tragic result. Once, the barrel filled with gunpowder exploded close to Santiago’s face, but luckily did no more harm than leave him with an eye infection and a permanent scar on his iris.

    However, Cajal was not only technically inclined, but also had great interest in drawing. In fact, he wanted to become a painter. His father, a university professor of anatomy, fused his son’s love of drawing with his enthusiasm for anatomy and got him interested in biology. The two supposedly stole corpses from a nearby cemetery then dissected them, and the youngster used his talent for drawing to learn the technique of anatomic illustration.

    In his memoirs, Cajal singled out this unusual period of his life as contributing the most to his later decision to become a scientist: “In front of the great anatomic desk which covered the dissecting table the brain as well as the stomach first shriveled in disgust. But they soon became used to it, and the corpses did not lead me to sad thoughts anymore, but reminded me of wonderful creations of life.”

    After finishing medical school he joined the Spanish Army as a doctor for a couple of years and spent a year on Cuba. There, he was unfortunate enough to contract malaria as well as tuberculosis, but this did not prevent him from marrying and having seven children after he returned. In 1881 he became a professor in Valencia, but it was several years earlier that he had used his modest savings to buy an old microscope with which he studied the structure of tissues and similar biological preparations.

    A method successful because it rarely works

    In Madrid in the year of 1887, when he was thirty-five, he met a psychiatrist friend who had just come back from Paris and brought with him a sample of brain tissue, prepared according to a special method invented by Camillo Golgi fourteen years earlier. Cajal was at that time compiling a book on the techniques used in histological research, which he intended to illustrate himself. He had a lot of difficulties with the studies of the nerve tissue, so his introduction to Golgi’s new method was a true revelation.

    The essential advantage of Golgi’s neuron staining method was that it almost never worked. It only colored one in approximately a thousand neurons, which was extremely important for observing the structure and functioning of the nerve tissue. This made it possible to observe a single neuron in a mass of neurons and examine it in detail. This is something like having a bowl of pasta in which most of the spaghetti are transparent and invisible and one or two are dyed in dark yet vivid colors.

    After learning about the new “black reaction” method, as Golgi’s staining technique was called, Cajal moved the focus of his research and came to many key conclusions about the structure and functioning of the nervous system. Before, it was believed that the brain was a mass of intertwined connections constituting networks, while Cajal, with his anatomical studies, demonstrated that the nervous system was also made of individual cells which were called neurons and through which nerve signals traveled.

    Even though both scientists used the same staining technique that Golgi had developed, their conclusions were diametrically opposed. The principal dispute was over whether neurons were completely independent and separate cells or whether they formed some sort of homogenous network.

    The objectivity argument

    Risba nevronov v nosu psa, Camillo Golgi, 1875.
    Camillo Golgi’s original black-and-white drawing of a dog’s olfactory bulb, 1875.

    When it came to interpreting their argument, drawings were of key importance. The difference between Cajal and Golgi was their differing opinions on how a scientist should ensure that his data is as reliable as possible. Basically, they were waging something like a war of images. They both criticized each other for not being objective: Cajal defended an unaltered representation and accused Golgi of intentionally interfering and modifying his descriptions, so that they corresponded to his own theoretical preferences.

    Cajal was convinced that a scientist should only copy what he sees in as much detail as possible and try not to interfere with that in the image he produces. According to him, a scientist should be like a camera, only transferring onto the image what he sees under the microscope. Golgi, on the other hand, was of the opinion that a scientific drawing should demonstrate the essence of the phenomenon it is describing and try to understand it. The duty of the scientist was supposed to lie in modifying a drawing, so that it reflects an ideal example, even though it might be composed of several examples of what can be seen under the microscope.

    Lorraine Daston, a director of the Max Planck Institute for the History of Science in Berlin, and Peter Galison, a professor of art history at Harvard University have emphasized in their book Objectivity (Zone books, MIT Press, 2007) that in trying to understand this interesting episode from the history of science it is necessary to realize that both scientists argued in good faith and that their sincere personal integrity should be viewed as the ideal of the true scientific approach. Both were convinced that their methods and consequently their conclusions were in accordance with the strictest principles of scientific work, so they firmly stuck to their beliefs.

    As the two historians elaborate their book, scientific objectivity has a checkered history. The scientists of the Age of Enlightenment, for example, gradually felt obligated to improve their drawings of plants and animals and ended up creating much better and more beautiful images than those they could observe in the nature. Golgi, who followed this enlightened ideal, made his drawings of the nervous system illustrative by allowing them to be interpretative, because he thought that best met the goal of his inquiry.

    However, as the historians clearly demonstrate with numerous examples, some scientists began to look upon such practice as a sin. Around the middle of the nineteenth century a new ideal of pursuing objectivity appeared, one which was in time defended by Cajal. “Let nature speak for itself!” became the motto for understanding scientific activity and the main question became how to describe and represent the world without creating the feeling of the presence of an actual observer. It was because of the pursuit of different ideals of how to portray objectivity in science that the two Nobel laureates began their dispute and their so-called war of images.