Cajal´s butterflies of the soul
By Javier DeFelipe
Most scientific figures presented in the nineteenth century and first third of the twentieth century were the drawings of early neuroanatomists, such as Santiago Ramón y Cajal (1852-1934) whose studies and theories had a profound impact on the researchers of his era and represent the true beginnings of the detailed analysis of the nervous system. Such illustrative work provided a valuable “pretext” for these scientists to express and develop their artistic talent.
Many of the illustrations of Cajal and other scientists can be considered to belong to different artistic movements, such as modernism, surrealism, cubism, abstraction, or impressionism. Cajal beautifully explained the combination of art and science in his book Recuerdos de mi vida-Historia de mi labor científica (“Recollections of my life-The story of my scientific work”, 1917), referring to the intellectual pleasure he felt when observing and drawing from his histological preparations:
My work began at nine o’clock in the morning and usually lasted until around midnight. Most curiously, my work caused me pleasure, a delightful intoxication, an irresistible enchantment. Indeed, leaving aside the egocentric flattery, the garden of neurology offers the investigator captivating spectacles and incomparable artistic emotions. In it, my aesthetic instincts were at last fully satisfied.
One of Cajal’s favorite topics was the study of the human cerebral cortex and he beautifully referred to the most common neurons in this brain region (the pyramidal cells) as the butterflies of the soul. He wrote at the beginning of his study of this region:
I felt at that time the most lively curiosity — somehow romantic — for the enigmatic organization of the organ of the soul. Humans — I said to myself — reign over Nature through the architectural perfection of their brains… To know the brain — we said to ourselves in our idealistic enthusiasm — is equivalent to discover the material course of thought and will… Like the entomologist hunting for brightly coloured butterflies, my attention was drawn to the flower garden of the grey matter, which contained cells with delicate and elegant forms, the mysterious butterflies of the soul, the beating of whose wings may some day (who knows?) clarify the secret of mental life … Even from the aesthetic point of view, the nervous tissue contains the most charming attractions. In our parks are there any trees more elegant and luxurious than the Purkinje cells from the cerebellum or the psychic cell that is the famous cerebral pyramid?
While looking at the captivating old illustrations it is exciting to think about the nature of our brain in romantic prose terms, a way of thinking that unfortunately we have lost in modern scientific writing. These illustrations represent the basis of our current understanding of the nervous system and their study represents a fascinating journey through the history of neuroscience since, by their very nature, they were an “interpretation” of the microscopic world rather than a reflection of absolute accuracy. Any scientist, who has used hand drawings for scientific illustrations (as I did during my early days at the Instituto Cajal), would no doubt agree that this is the case. Like a painter of natural scenery, the scientists of the past did not reproduce the entire field of the histological preparations they observed through the microscope. They only illustrated those elements they thought to be important for what they wanted to describe. Therefore, it was not necessarily free of technical errors, making this early period of neuroscience an interesting page of history where the exchange of information between scientists was hindered by inevitable skepticism concerning findings. However, there can be little doubt that this era was also a golden period of art in neuroscience.
Javier DeFelipe, PhD is a Research Professor at the Instituto Cajal (CSIC) located in his hometown, Madrid, Spain. He is the author of Cajal’s Butterflies of the Soul: Science and Art.