The beautiful brain. The drawings of Santiago Ramon y Cajal
Title : The beautiful brain. The drawings of Santiago Ramon y Cajal.
Author : Essays by Larry W. Swanson, Lyndel King and Eric Himmel
Editors : Eric A Newman, Alfonso Araque, Janet M Dubinsky
Paperback Publisher : Abrams, New York
Year : 2017.
Number of pages : Hardcover. 208 pages
Cost : $28.00.
The editors have impressive credentials. Dr. Eric Newman, Dr. Afonso Araque and Dr. Janet Dubinsky work at the University of Minnesota. Dr. Newman's research interest parallels that of Dr. Araque but also includes the interactions between glia and blood vessels in the nervous system. In a recent paper, he has described the mechanisms governing functional hyperemia in the brain, including the role of glial calcium-signaling in mediating neurovascular coupling and the manner in which arachidonic acid from neurons diffuses into astrocytic end feet leading to the formation of vasoactive metabolites. As we shall see below, this is especially appropriate.
Dr. Araque studies astrocyte-neuron signaling and synaptic physiology. Traditionally astrocytes have been assigned the role of support structures for neurons and axons. Dr. Araque and his team describe astrocytes as relevant elements in brain function by showing how astrocytes respond to neuronal activity, how they control neuronal activity and synaptic transmission and plasticity, and how they are involved in neural network function. One of his publications has an especially apt title – Do stars govern our actions? The stars referred to are astrocytes. In another paper, he has described Cajal's own contributions to the physiological significance of neuroglia. (Frontiers in neuroanatomy 2014;8:1-5).
Dr. Dubinsky is specially interested in mitochondria in the normal brain and in diseases such as Huntington's chorea. Among the courses she teaches are Neuroscience and society (including discussions on ethics in the neurosciences) and Neuroscience in the community (where students are encouraged to partner teachers in middle schools).
The book features essays by Drs. Larry W. Swanson, Lyndel King and Eric Himmel.
Dr. Larry Swanson has written books on the classical origins and historical foundations of the terms used in neuroanatomy and the basic structure of the brain. He has helped map the structure of the brain of the rat. He works at the University of Southern California and is the past President of the Society for Neuroscience.
Dr. Lyndel King has been acclaimed for her vision and passion that led to the completion of the Weisman Museum at the University of Minnesota. A report in MinnPost provides an instance of her enthusiastic approach. “In the film (used by her to stimulate her colleagues), King Henry V is leading his exhausted English footmen across Northwestern France, frightfully outnumbered by French forces. The king rallies them with one of the most famous leadership speeches in English literature: The fewer men, the greater share of honor.… He who hath no stomach for this fight let him depart.… We few, we happy few, we band of brothers, for he today that sheds his blood with me shall be my brother. The words are intense and inspired. Lyndel King summoned those words in a move that was characteristic of her intense, inspired and audacious bid to bring the Weisman Art Museum to its full stature at the University of Minnesota. She sent the clip to her staff in the wind-up weeks before the October grand reopening of the expanded museum, now known as WAM. Oh, for good measure, she also brought her troops ample supplies of jelly beans, something poor King Henry didn't have at his disposal. ' It gives people strength,' she declared with authority. 'I just know that sugar works.'
Mr. Eric Himmel is Vice-President and editor in chief at Abrams Books in New York. You will find photographs of the celebration of his 30th year at Abrams at https://www.flickr.com/photos/abrams_books/sets/72157623727109804.
The opening chapter summarizes the contents of the book. Dr. Swanson describes the life and work of Dr. Cajal. Drs. Lyndel King and Eric Himmel demonstrate the unique drawings that Dr. Cajal made to illustrate his understanding of the human brain. These drawings are grouped under three classes: the cells within the brain, the sensory system and the neuronal pathways and, in the final section, those on the development of the nervous system and its diseases.
Dr. Dubinsky places these historic drawings in the modern context, telling us of advances since Dr. Cajal completed his work.
Dr. Santiago Ramón y Cajal (1852-1934) was born in Petilla de Aragon in north-east Spain. His name follows Spanish customs. The first or paternal family name is Ramón and the second or maternal family name is Cajal. 'y' stands for 'and'.
Grandson of a farmer and son of a doctor, he was shy and unsociable as a child, with a penchant for getting into trouble. His first publication at the age of 14 was Estrategia lapidaria which, Dr. Swanson tells us, was a treatise on how to design and use slingshots!
The frontispiece features four self-portraits taken by Dr. Cajal in 1886, at the age of 34. The lower two show a pensive, bearded individual whilst the two above show him cutting sections on his microtome, the microscope lying just ahead. The visage familiar to us is seen in the self-portrait in 1910, taken in his late fifties. A bottle to his left is labeled sulfito de sosa. The dictionary translates sosa as caustic soda. Another bears the label sulfato cobre – copper sulphate. On page 10, we see a self-portrait taken in 1920, at the age of 68. There are other portraits by himself as well. You might wonder at the tendency to make selfies well before this term was coined.
By the age of 8, he was drawing his collection of birds, bird's eggs and their nests. He taught himself the techniques described by Louis Daguerre (1787-1851) and developed and printed all his photographs. Drawing and photography were to remain life-long passions. Indeed, he dreamt of a career as an artist. This fortunate talent resulted in the availability of photographs documenting several stages of his life. (For more on his photography download López-Cantos' paper 'Photography in the boundaries of the visible from Santiago Ramón y Cajal to Cecil Frank Powell.' from https://doi.org/10.1080/23311983.2016.1182715)
Dr. Cajal later described how he preferred to learn by seeing, observing and taking things apart rather than by memorizing and listening to dry lectures. His observational stamina can be gauged from the fact that he once 'spent twenty hours continuously at the microscope watching the movements of a sluggish leukocyte in its laborious efforts to escape from a capillary.' This patience, skill and mental discipline contributed to his emergence as a noteworthy field guide to the neuronal forest.
His father, Justo Ramón Casasus, hit upon the stratagem of persuading his son to take up medicine as a career. Initially, he made his son an accomplice in grave robbing to obtain human bones for study. He then coaxed him to teach anatomy to students in the nearby medical school in Zaragoza. Writing about his father in later years, Dr. Cajal described him as his first teacher and exclaimed, 'To construct original brains, that is the great triumph of the teacher.'
Dr. Cajal found the structure of man fascinating and was soon drawing from his dissections. He enrolled as a medical student and graduated as a licentiate of medicine at the age of 29. Enfeebled by an attack of malaria during service in the army medical corps in Cuba, he opted to teach medicine instead of practicing it.
In 1875, he purchased a Verick microscope and a Ranvier microtome to be used at home to study minute anatomy. Histology had developed into a discipline by the 1840s with the Germans, Dr. Matthias Jakob Schleiden (1804-1881) and Dr. Theodore Schwann (1810-1882), leading the way. Dr. Cajal's first publication in 1880 was on the histological study of the changes following injury. (His illustrations of changes in the nervous system following injury are to be found in the section entitled Development and pathology.)
This year was also memorable as he married Ms. Silveira Garcia.
At the age of 33, Dr. Cajal was promoted to the post of Professor of Anatomy in Valencia. In 1889, he published a textbook of histology.
His explanation on his choice for a career, published in Recollections of my life, encapsulates his philosophy: 'I finally chose the cautious path of histology, the way of tranquil enjoyments. I knew well that I should never be able to drive through such a narrow path in a luxurious carriage; but I should feel myself happy in contemplating the captivating spectacle of minute life in my forgotten corner and listening, entranced, from the ocular of my microscope, to the hum of the restless beehive which we all have within us.' I found myself pondering on the act of 'listening' to what the microscope showed, and 'the hum of the restless beehive' perceived from inanimate histological sections.
Dr. Sherrington, with his perspicacity, described Dr. Cajal's genius thus: 'A trait very noticeable in (Dr. Cajal) was that in describing what the microscope showed, he spoke habitually as though it were a living scene…He treated the microscopic scene as though it were alive and were inhabited by beings which felt and did and hoped and tried even as we do. It was a personification of the natural forces as unlimited as that of Goethe's Faust Part 2…' (Dr. Cajal visited England just once, when he was invited by the Royal Society to deliver the Croonian Lecture. He was Dr. Charles Sherrington's guest during this visit. Dr. Sherrington's account, entitled A memoir of Dr. Cajal forms an excellent prefatory note to the biography of Dr. Cajal by Dorothy Cannon. This book can be downloaded from https://archive.org/details/in.ernet.dli.2015.63985).
On his return to Madrid, he wrote: 'My attention hunted in the flower garden of the gray matter cells with delicate and elegant forms, the mysterious butterflies of the soul, the beatings of whose wings may some day… clarify the secret of mental life.' (McMenemey WH: Santiago Ramon y Cajal (1852-1934) Proceedings of the Royal Society of Medicine 1952;46:173-176).
Propulsion into the field of neuroanatomy appears to have followed 'the fateful moment in 1887 when Cajal peered down the microscope at a slide of nervous tissue prepared with the method described by Golgi.' The clarity with which nerve cells and their processes could be seen as deep black silhouettes against a light-yellow background aroused both the scientist and the artist in him. Over the next year, Dr. Cajal refined the staining technique developed by Dr. Camillo Golgi (1843-1926). 'He often worked fifteen hours a day, complaining that each discovery cost a night's sleep.' In 1890, he published fourteen illustrated papers with clear demonstrations of the nerve cells, their dendrites and their axons.
Dr. Golgi had demonstrated cell bodies, their long slender cables that did not branch and the clusters of shorter branching fibres but failed to differentiate between axons and dendrites. He did not refute German histologist Dr. Joseph Gerlach's postulate of the reticular structure of the brain.
The two volumes of Dr. Cajal's Histologie du système nerveux de l'homme et des vertébrés, published in 1909 and 1911 contained more than a thousand illustrations. He demolished the theory, held since the days of Joseph Gerlach (1820-1896), that the nervous system has an ill-defined network or reticulum. He also laid down the concept of neurons, axons, dendrites and glial cells that we continue to use.
Other major works on neuroanatomy and on colour photography followed. Equally cherished are his autobiography and his Advice for a young investigator.
Dr. Cajal shared the Nobel Prize with the Italian Dr. Camillo Golgi in 1906. The tantrum by Dr. Golgi at this award marred the event. Dr. Cajal opined that functions such as this demand 'a heart of steel, the skin of an elephant and the stomach of a vulture.'
When Drs. Wilder Penfield and Del Rio Hortega visited Dr. Cajal towards the end of his life, they found him with a cold, propped up in bed, surrounded by manuscripts. 'Deafness and feebleness which had come on him recently were shutting doors behind him and the world but his eyes blazed under shaggy brows showing an unquenched fire.' (McMenemy 1952) He died peacefully in his eighty-third year, on 17 October 1934, and lies buried in the necropolis of Madrid, next to his wife of 54 years.
The book under review appears to have been produced both for the scientist and the lay person as the editors found it necessary to explain that the neurones are 'the nerve cells that comprise the brain' and clarify the need to use chemical stains on thin slices of the brain.
The book contains high quality reproductions of eighty of Dr. Cajal's drawings. Some have not been reproduced earlier except in Dr. Cajal's scientific papers.
There is also a profusion of photographs taken by Dr. Cajal, including one in colour taken in 1912.
King and Himmel's brief chapter on Dr. Cajal's drawings applauds Leonardo da Vinci's anatomical studies and drawings but fails to credit Leonardo's younger rival, Michelangelo, who had actually planned to write a text on human anatomy illustrated by his own dissections.
They rightly applaud Dr. Cajal's 3000 and more drawings as 'unprecedented in the history of modern science' as creations by a single author illustrating and illuminating the basic facts of nature. Their description of how he made these drawings enhance our admiration for them for he spurned the camera lucida and preferred freehand drawing. Several of his drawings were entirely from memory! He would return to the microscope merely to confirm the accuracy of what he had put on paper. They explain the whitened-out areas and numbers placed by Dr. Cajal on the illustration used on the cover of this book as well as those within. Since money was always in short supply, he often made the photolithographic plates for the printer himself. He used what was later described as the time-lapse technique to illustrate stages in the development of a neuron (see page 159). King and Himmel serve as guides and commentators on several of the drawings in the next section. I especially enjoyed their comment on the penguin in the drawing on page 170. They bring alive Dr. Cajal's imagery in words, using botanical metaphors to explain what he saw in the formal garden and intricate forest within the brain. Dr. Cajal's comments on 20th century modern art, surrealism and cubism will interest many.
The crux of the book lies between pages 33 and 191. Here we can study Dr. Cajal's drawings on the cells of the brain, sensory systems, neuronal pathways and illustrations on the development of the brain and the consequences of injury and disease. Each illustration has an explanatory note on the facing page that enriches our understanding.
The illustration on pages 146 shows the reticular structure of the brain championed by Gerlach. On the facing page, we see Dr. Cajal's finding of distinct neurons, their processes and synapses. The reticulum theory was finally and permanently laid to rest with the advent of electron microscopy in the 1930s and its increasing use in the neurosciences from the 1950s.
The note on page 74 explaining Dr. Cajal's drawing of gray matter astrocytes in the spinal cord also provides a quotation from Dr. Cajal: 'Every astrocyte of the white or gray matter is provided with a sucking apparatus or perivascular pedicle… The purpose of these elements is to provoke, by contraction of such appendages, local dilation of these vessels and thus increased blood flow linked to the intensity of the mental processes.' King and Himmel bring us up to date on the subject: 'A century later, research has shown Dr. Cajal to be largely correct. Although astrocyte end feet do not contract, they do release chemicals that cause blood vessels to dilate…' Astrocytic end feet against a capillary are clearly shown in Dr. Cajal's diagram on the opposite page.
It was postulated that apart from providing insulation, structural support and nutrition to neurons, astrocytes participated in the information processing functions within the brain. The note on page 73 describing Dr. Cajal's drawing of an astrocyte in the human hippocampus refers to his description of the cerebral astrocytes as constituting 'a vast endocrine gland', releasing chemical signals associated with brain activity. King and Himmel point out that Dr. Cajal was close to the mark as astrocytes do release gliotransmitters on to synapses and thus modulate the electrical responses of neurons.
Dr. Cajal termed the pyramidal neuron the 'noble and enigmatic cell of thought'. He also studied in detail the Purkinje's cells and his diagram of a human cerebellar Purkinje neuron is placed on the cover of this book. His drawings of these cells – in man and in the pigeon - are in common usage in neuroanatomical publications to this date.
Each drawing selected for reproduction in this book deserves careful study. Taken together – and we must remember that they are just a small sample from the 12,000 drawings made by Dr. Cajal (of which about 3000 remain) – they serve to provoke intense admiration for his outstanding abilities.
The concluding essay by Dr. Dubinsky shows us some of the changes since Dr. Cajal's epochal work ended. She points out that whilst Dr. Cajal worked with sections varying from 1 to 100 microns in thickness, modern scientists work on sections varying from 0.1 to 0.0001 microns. Standing on the shoulders of giants such as Drs. Cajal, Golgi, Edinger, Kölliker, His, Forel and Retzius, we can now access details much subtler than those available to them. The ability to reconstruct findings under light and electron microscopes in three dimensions and colour; neurochemistry; crystallography and genetics of high order; and tools such as magnetic resonance imaging have further improved our understanding of the brain which, as Emily Dickinson put it, is 'wider than the sky and deeper than the sea.'
Although the drawing on page 159 depicts Dr. Cajal's illustration showing the stages of the development of a neuron, I failed to find a reference to the Dr. Cajal-Retzius cell. (It is also not referred to in the index.) He had described these slender horizontal bipolar cells in the brain of Lagomorphs (the mammalian order that includes hares and rabbits) in 1891. Dr. Gustaf Retzius described them in human foetuses in 1893. Dr. Cajal, studying the human foetus in 1899, described them in layer 1 of the cerebral cortex at term and in the newborn. The morphological details provided by these pioneers differed a little. Similar cells were also found in the hippocampus. They have since been shown to use glutamate as their transmitter and are linked to the production of reelin. They play a role in the organisation of the developing human brain. Abnormalities in the production and activity of these cells may be related to a variety of developmental abnormalities of the brain.
Dr. Cajal's drawings illustrate not only the magnificent structure and function of our nervous systems but also vindicate the quotation from the works of Saint Augustine used by Dorothy Cannon at the start of the first chapter of her book on Dr. Cajal: 'Man wonders over the restless sea, the flowing water, the sight of sky and forgets that of all wonders, man himself is the most wonderful.'
This book will be especially treasured by those interested in the neurosciences and their history, and the life and work of Dr. Santiago Ramon y Cajal.