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Beautiful Brain: The Stunning Drawings of Neuroscience Founding Father Santiago Ramón y Cajal

“A graphic representation of the object observed guarantees the exactness of the observation itself.”

Oliver Sacks insisted that “ideas emerge, are shaped, in the act of writing,” which he considered “a special, indispensable form” of talking to himself. Unusual creature though he was, the beloved neurologist was not the only scientist who turned to other forms of creative expression as a clarifying force for scientific inquiry. The Spanish histologist, onetime bodybuilder, selfie pioneer, and Nobel laureate Santiago Ramón y Cajal (May 1, 1852–October 17, 1934), widely considered the founding father of modern neuroscience, used drawing the way Dr. Sacks used writing — as a vital way of thinking out loud, of giving form to ideas, of making arguments and fleshing out theories around the skeleton of observations.

Cajal — who, given the magnitude of his contributions, ought to be as much of a household name as Darwin and Pasteur — created hundreds of exquisite, exceptionally skilled drawings to illustrate his scientific papers. In them, he laid out the basic architecture of the nervous system and tackled the grand unanswered question of his era: How do nerve impulses travel between separate cells, or, what is the neurological basis of reflexes? Art became the sandbox for testing his theories, which in turn became a centerpiece of modern science.

The best of his drawings, ranging from the iconic to the never-before-published, are now collected in Beautiful Brain: The Drawings of Santiago Ramón y Cajal (public library) — astonishingly detailed and deft illustrations, some reminiscent of Johannes Hevelius’s 17th-century comet drawings and others of the tree diagrams of medieval manuscripts.

Glial cells of the cerebral cortex of a child

Cajal was drawn to art from an early age, to a point of compulsion — as a boy, he was frequently possessed by what he called “manias” to draw everything in sight, and even drew his dreams. At sixteen, he fell in love with photography, particularly with the photographic process Daguerre had invented three decades earlier, and taught himself how to take, develop, and print daguerrotypes. A century and a half before the selfie, he produced a lifelong series of remarkably artful photographic self-portraits.

Self-portrait by Cajal at his library in his thirties
Self-portrait by Cajal at his laboratory in his thirties

But Cajal’s father, a physician, was unthrilled by his son’s artistic pursuits and hoped the boy would instead follow in his own footsteps. In an attempt to gently steer his course away from art and toward science, he persuaded young Santiago to help him teach anatomy at the local medical school. The plan was both a success and a failure — it only amplified Cajal’s passion for art, but it also kindled a lively interest in science. Like Leonardo, who made porous the membrane between art and science and who was a prescient anatomist, Cajal became enchanted by the mysteries of the human body and used his meager savings to build a home laboratory where he could undertake histology — the study of body tissues through a microscope.

The medial geniculate nucleus in the thalamus of the cat

Both in scope and in promise, histology fell partway between anatomy, which had been a staple of medicine for centuries, and microbiology, which Pasteur had rendered a research field du jour. The obscure discipline was in its infancy, its growth only recently accelerated by innovations in optical technology in the 1830s, but Cajal saw it as full of possibility. He would later write his poetic autobiography, Recollections of My Life:

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 [as microbiology] 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 the microscope, to the hum of the restless beehive which we all have within us.

Calyces of Held — synapses made by axons carrying auditory information and contacting neurons in a brainstem structure called the trapezoid body

It was from this transfixed vantage point at the eyepiece of the microscope that Cajal, who always considered himself “a visual type,” first saw the potential of fusing science with art in advancing discovery. At the University of Barcelona, he learned of the Golgi method — a technique pioneered by the Italian physician Camillo Golgi, using potassium dichromate and silver nitrate to stain neurons in black. It worked beautifully but unpredictably — there was no control over which neurons would be stained and which wouldn’t, rendering the results uneven and unreliable.

The pyramidal neuron of the cerebral cortex
A Purkinje neuron from the human cerebellum

Cajal toiled tirelessly to improve the technique until its scientific reliability was as spectacular as its aesthetic splendor — a feat he accomplished in 1888, which he considered his “year of fortune,” his very own pre-Einsteinian annus mirabilis. In a passage that calls to mind Alan Lightman’s beautiful writings about the creative sympathies between scientific and artist breakthrough, Cajal would later write:

The new truth, laboriously sought and so elusive during two years of vain efforts, rose up suddenly in my mind like a revelation… Realizing that I had discovered a rich field, I proceeded to take advantage of it, dedicating myself to work, no longer merely with earnestness, but with a fury.

In the grip of that fury, he worked fifteen-hour days and in a single year published fourteen scientific articles on the nervous system, which at the time was an enigmatic terra incognita.

An astrocyte in the human hippocampus
Pyramidal neurons of the central cortex and their axon pathways
The embryonic spinal cord

But even through his most groundbreaking scientific discoveries, Cajal remained at heart a Renaissance man. His books included a treatise on the technology and art of color photography, a compendium of aphorisms à la Oscar Wilde, a book of advice to young scientists à la Rilke, and a collection of science fiction short stories. He deliberately divided his autobiography into two parts, one exploring his artist passions and the other his scientific career.

Superior colliculus of the kitten
Diagram illustrating how information from the eyes might be transmitted to the brain

There was an almost daredevil aspect to Cajal’s choice to study the brain — the often controversial and infinitely challenging Everest of science at the end of the nineteenth century. Bodies fell along the way as some of the world’s most ambitious scientists attempted to reveal its mysterious inner workings. In one of the essays in the monograph, curator Lyndel King and editor Eric Himmel consider the visionary approach that elevated Cajal above the rest:

At best, a brain slice seen through a microscope is notoriously difficult to interpret. To borrow one of Cajal’s favorite metaphors, imagine entering a forest with a hundred billion trees armed only with a sketchbook, looking each day at blurry pieces of a few of those trees entangled with one another, and, after a few years of this, trying to write an illustrated field guide to the forest. You won’t get anywhere if you simply draw what you see every day; you’re going to have to build up a mental inventory of rules for the forest, and then scrupulously try to fit what you see into that framework, or be flexible enough to allow what you see to reshape your stock of ideas.

A generation earlier, the great Victorian art critic John Ruskin had argued that drawing cultivates the art of observation and helps one see the world more clearly. Cajal brought this ethos to his scientific work, using his illustrations — which he preferred to do freehand, rather than tracing images projected from a microscope — to deduce the framework of how the brain works. He would later write:

A graphic representation of the object observed guarantees the exactness of the observation itself.

But Cajal also cared deeply about the aesthetic quality of the art itself — he took great pains with his draughtsmanship and, at the start of his career, pooled his meager resources to pay for high-quality printing.

The labyrinth of the inner ear
The olfactory bulb of the dog

King and Himmel consider the integral role of Cajal’s art in his ultimate legacy as a scientist:

As with Einstein’s theories, it has taken many decades for those of us who are not scientists to catch up with Cajal’s brain. It wasn’t until 1946, twelve years after Cajal’s death, that the first electronic computer flickered into life, hinting that a machine could be built that behaved like a brain. That day may be (infinitely) far off, but since then, the concepts that Cajal discovered, explained, and illustrated have burrowed into the world’s technology, economy, popular myths, moral dilemmas, philosophical debates, and art and literature. Since Cajal, we have seen mounting evidence that the idea of the brain being as vast and mysterious as the universe — for centuries a trope for poets — may contain some literal truth. When we look at his drawings today, we see not diagrams or arguments, but the first clear pictures of that remote frontier, drawn by the man who traveled farthest into its endless reaches.

Complement the scrumptious Beautiful Brain, annotated with fascinating background on each of Cajal’s drawings, with Peter Rabbit creator Beatrix Potter’s little-known mycological illustrations and Leonardo da Vinci’s visionary anatomical drawings, centuries ahead of medicine, then revisit this modern-day graphic novel about how the brain works, built upon Cajal’s legacy.

Images courtesy of Abrams Books


How the French Mathematician Sophie Germain Paved the Way for Women in Science and Almost Saved Gauss’s Life

“The taste for the abstract sciences in general and, above all, for the mysteries of numbers, is very rare… since the charms of this sublime science in all their beauty reveal themselves only to those who have the courage to fathom them.”

How the French Mathematician Sophie Germain Paved the Way for Women in Science and Almost Saved Gauss’s Life

A century after the trailblazing French mathematician Émilie du Châtelet popularized Newton and paved the path for women in science, and a few decades before the word “scientist” was coined for the Scottish mathematician Mary Somerville, Sophie Germain (April 1, 1776–June 27, 1831) gave herself an education using her father’s books and became a brilliant mathematician, physicist, and astronomer, who pioneered elasticity theory and made significant contributions to number theory.

In lieu of a formal education, unavailable to women until more than a century later, Germain supplemented her reading and her natural gift for science by exchanging letters with some of the era’s most prominent mathematicians. Among her famous correspondents was Carl Friedrich Gauss, considered by many scholars the greatest mathematician who ever lived. Writing under the male pseudonym M. LeBlanc — “fearing the ridicule attached to a female scientist,” as she herself later explained — Germain began sharing with Gauss some of her theorem proofs in response to his magnum opus Disquisitiones Arithmeticae.

Sophie Germain

Their correspondence began in 1804, at the peak of the French occupation of Prussia. In 1806, Germain received news that Napoleon’s troops were about to enter Gauss’s Prussian hometown of Brunswick. Terrified that her faraway mentor might suffer the fate of Archimedes, who was killed when Roman forces conquered Syracuse after a two-year siege, she called on a family friend — the French military chief M. Pernety — to find Gauss in Brunswick and ensure his safety. Pernety tasked one of his battalion commanders with traveling two hundred miles to the occupied Brunswick in order to carry out the rescue mission.

But Gauss, it turned out, was unscathed by the war. In a letter from November 27 of 1806, included in the altogether fascinating Sophie Germain: An Essay in the History of the Theory of Elasticity (public library), the somewhat irate battalion commander reports to his chief:

Just arrived in this town and have bruised myself with your errand. I have asked several persons for the address of Gauss, at whose residence I was to gather some news on your and Sophie Germain’s behalf. M. Gauss replied that he did not have the honor of knowing you or Mlle. Germain… After I had spoken of the different points contained in your order, he seemed a little confused and asked me to convey his thanks for your consideration on his behalf.

Carl Friedrich Gauss (Portrait by Jensen)

Upon receiving the comforting if somewhat comical news, Germain felt obliged to write to Gauss and clear his confusion about his would-be savior’s identity. After coming out as the woman behind the M. LeBlanc persona in a letter from February 20 of 1807, she tells Gauss:

The appreciation I owe you for the encouragement you have given me, in showing me that you count me among the lovers of sublime arithmetic whose mysteries you have developed, was my particular motivation for finding out news of you at a time when the troubles of the war caused me to fear for your safety; and I have learned with complete satisfaction that you have remained in your house as undisturbed as circumstances would permit. I hope, however, that these events will not keep you too long from your astronomical and especially your arithmetical researches, because this part of science has a particular attraction for me, and I always admire with new pleasure the linkages between truths exposed in your book.

Gauss responds a few weeks later:


Your letter … was for me the source of as much pleasure as surprise. How pleasant and heartwarming to acquire a friend so flattering and precious. The lively interest that you have taken in me during this war deserves the most sincere appreciation. Your letter to General Pernety would have been most useful to me, if I had needed special protection on the part of the French government.

Happily, the events and consequences of war have not affected me so much up until now, although I am convinced that they will have a large influence on the future course of my life. But how I can describe my astonishment and admiration on seeing my esteemed correspondent M. LeBlanc metamorphosed into this celebrated person, yielding a copy so brilliant it is hard to believe? The taste for the abstract sciences in general and, above all, for the mysteries of numbers, is very rare: this is not surprising, since the charms of this sublime science in all their beauty reveal themselves only to those who have the courage to fathom them. But when a woman, because of her sex, our customs and prejudices, encounters infinitely more obstacles than men in familiarizing herself with their knotty problems, yet overcomes these fetters and penetrates that which is most hidden, she doubtless has the most noble courage, extraordinary talent, and superior genius. Nothing could prove me in a more flattering and less equivocal way that the attractions of that science, which have added so much joy to my life, are not chimerical, than the favor with which you have honored it.

The scientific notes which your letters are so richly filled have given me a thousand pleasures. I have studied them with attention, and I admire the ease with which you penetrate all branches of arithmetic, and the wisdom with which you generalize and perfect. I ask you to take it as proof of my attention if I dare to add a remark to your last letter.

With this, Gauss extends the gift of constructive criticism on some mathematical solutions Germain had shared with him — the same gift which trailblazing feminist Margaret Fuller bestowed upon Thoreau, which shaped his career. Although Gauss eventually disengaged from the exchange, choosing to focus on his scientific work rather than on correspondence, he remained an admirer of Germain’s genius. He advocated for the University of Gottingen to award her a posthumous honorary degree, for she had accomplished, despite being a woman and therefore ineligible for actually attending the University, “something worthwhile in the most rigorous and abstract of sciences.”

She was never awarded the degree.

Red fish pond in front of the girls’ school named after Germain

After the end of their correspondence, Germain heard that the Paris Academy of Sciences had announced a prix extraordinaire — a gold medal valued at 3,000 francs, roughly $600 then or about $11,000 now — awarded to whoever could explain an exciting new physical phenomenon scientists had found in the vibration of thin elastic surfaces. The winning contestant would have to “give the mathematical theory of the vibration of an elastic surface and to compare the theory to experimental evidence.”

The problem appeared so difficult that it discouraged all other mathematicians except Germain and the esteemed Denis Poisson from tackling it. But Poisson was elected to the Academy shortly after the award was announced and therefore had to withdraw from competing. Only Germain remained willing to brave the problem. She began work on it in 1809 and submitted her paper in the autumn of 1811. Despite being the only entrant, she lost — the jurors ruled that her proofs were unconvincing.

Germain persisted — because no solution had been accepted, the Academy extended the competition by two years, and she submitted a new paper, anonymously, in 1813. It was again rejected. She decided to try a third time and shared her thinking with Poisson, hoping he would contribute some useful insight. Instead, he borrowed heavily from her ideas and published his own work on elasticity, giving Germain no credit. Since he was the editor of the Academy’s journal, his paper was accepted and printed in 1814.

Still, Germain persisted. On January 8, 1816, she submitted a third paper under her own name. Her solution was still imperfect, but the jurors decided that it was as good as it gets given the complexity of the problem and awarded her the prize, which made her the first woman to win an accolade from the Paris Academy of Sciences.

But even with the prize in tow, Germain was not allowed to attend lectures at the Academy — the only women permitted to audit were the wives of members. She decided to self-publish her winning essay, in large part in order to expose Poisson’s theft and point out errors in his proof. She went on to do foundational mathematical work on elasticity, as well as work in philosophy and psychology a century before the latter was a formal discipline. Like Rachel Carson, Germain continued to work as she was dying of breast cancer. A paper she published shortly before her terminal diagnosis precipitated the discovery the laws of movement and equilibrium of elastic solids.

Her unusual life and enduring scientific legacy are discussed in great detail in the biography Sophie Germain. Complement it with the stories of how Ada Lovelace became the world’s first computer programmer, how physicist Lise Meitner discovered nuclear fission, was denied the Nobel Prize, but led the way for women in science anyway, and how Harvard’s unsung 19th-century female astronomers revolutionized our understanding of the universe decades before women could vote.


Bruce Lee’s Never Before Revealed Letters to Himself About Authenticity, Personal Development, and the Measure of Success

“Where some people have a self, most people have a void, because they are too busy in wasting their vital creative energy to project themselves as this or that, dedicating their lives to actualizing a concept of what they should be like rather than actualizing their potentiality as a human being.”

“This is the entire essence of life: Who are you? What are you?” So wrote young Leo Tolstoy in his diary of moral development. Bruce Lee (November 27, 1940–July 20, 1973) was around Tolstoy’s age when he turned to this central question of existence more than a century later and approached it with the same subtleness of insight and sincerity of spirit with which he approached all of life.

Bruce Lee (Photograph courtesy of the Bruce Lee Foundation archive)
Bruce Lee (Photograph courtesy of the Bruce Lee Foundation archive)

Revered by generations as the greatest martial artist in popular culture, Lee is increasingly being recognized as the unheralded philosopher that he was, from his famous metaphor for resilience to his recently revealed unpublished writings on willpower, imagination, and confidence. But his most intently philosophical work was the personal credo statement he wrote in the final year of his life, at the age of thirty-one, as a series of letters to himself under the heading “In My Own Process.” The piece underwent nine drafts, never finished and never published, which I’m delighted to share for the first time with special permission from Lee’s daughter, Shannon Lee, and the Bruce Lee Foundation.

Bruce Lee (Photograph courtesy of the Bruce Lee Foundation archive)

The timing of “In My Own Process” is also significant, for Lee began writing it at a pivotal point in his life. After years of being sidelined by the Hollywood studio system, which continued to cast Caucasian actors to play Asian lead characters, Lee finally got his big break and was cast as the lead in Enter the Dragon, the script for which he helped write. But when Warner Brothers pushed to cut out all the philosophy and turn the film into a mindless action movie, Lee refused to show up on set in protest — he firmly believed that the kung fu was merely the vehicle for the deeper philosophical message, rather than the philosophy being a distraction from the kung fu, as Warner Brothers implied.

Well aware that his principles could cost him the fulfillment of his lifelong dream, he stood his ground. After a two-week standstill, the studio relented and let Lee keep the philosophical elements, so production began.

Bruce Lee on set (Photograph courtesy of the Bruce Lee Foundation archive)

In the midst of this busiest and most tumultuous period of his career, Lee made deliberate time for self-reflection in drafting his credo. It was in these letters to himself, written in his third language over the course of several months on a colorful variety of stationery, that he arrived at the concept of being an “artist of life.” In them, he examines with great simplicity and wisdom some of the most elemental questions of existence. Decades before the Harvard psychologist Dan Gilbert made his memorable assertion that “human beings are works in progress that mistakenly think they’re finished,” Lee considers with acute self-awareness the mutability of what we experience as the “self.” Echoing the poet Laura Riding’s conviction that “nothing is really important but being oneself,” he maintains through the various revisions that all knowledge is self-knowledge — the seedbed of his oft-cited assertion that “the greatest help is self-help” — and that personal authenticity is the object of life and the only real measure of success.

“In My Own Process,” Draft 1 (Courtesy of the Bruce Lee Foundation archive)

In the first draft, he writes:

Any attempt to write a somewhat meaningful article — or else why write it at all — on how I, Bruce Lee by name, emotionally feel or how my instinctive honest reaction toward circumstances is no easy task. Why? Because I am a changing as well as an ever-growing man. Thus what I held true a couple of months ago might not [be] the same now.

“In My Own Process,” Draft 2 (Courtesy of the Bruce Lee Foundation archive)

In the second draft, after relaying the difficulty of conducting this self-examination in the midst of his grueling work schedule, he insists on the importance of personal authenticity above all else and considers the vital difference between what Hannah Arendt called being vs. appearing and Kahlil Gibran contrasted as the seeming self vs. the authentic self. Lee writes:

Of course, this writing can be made less demanding should I allow myself to indulge in the standard manipulating game of role playing, but my responsibility to myself disallows that… I do want to be honest, that is the least a human being can do… I have always been a martial artist by choice, an actor by profession, but above all, am actualizing myself someday to be an artist of life. Yes, there is a difference between self-actualization and self-image actualization.

“In My Own Process,” Draft 3 (Courtesy of the Bruce Lee Foundation archive)

In the third draft, he considers our chronic fear of the unfamiliar in a sentiment of particular poignancy at this political moment:

Among people, a great majority don’t feel comfortable at all with the unknown — that is anything foreign that threatens their protected daily mould — so for the sake of their security, they construct chosen patterns to justify.

“In My Own Process,” Draft 4 (Courtesy of the Bruce Lee Foundation archive)

In the fourth draft, Lee turns to the perpetual evolution of personhood, which renders the idea of static self-definition unnecessary and unhelpful:

I have come to accept life as a process, and am satisfied that in my ever-going process, I am constantly discovering, expanding, finding the cause of my ignorance, in martial art and especially in life. In short, to be real…

“In My Own Process,” Draft 5 (Courtesy of the Bruce Lee Foundation archive)

In the fifth draft, the revisits the inherent paradox of the quest to define himself and his process:

I don’t believe in the manipulation game of creating a self image robot.

“In My Own Process,” Draft 6 (Courtesy of the Bruce Lee Foundation archive)
“In My Own Process,” Draft 7 (Courtesy of the Bruce Lee Foundation archive)

In the seventh draft, he echoes Walt Whitman’s incantation to “re-examine all you have been told at school or church or in any book,” and writes in a passage of especial relevance to our present epidemic of unquestioned “alternative facts”:

Surely we all admit that we are intelligent beings, though in reality we are being crammed with ready-made facts handed down to us ever since [childhood]. Some of us even went through college but something is the matter because … some of these facts are examined in the form of self-inquiry, but in most cases we accept most of these facts unexamined.


We possess a pair of eyes to help us to observe as well as to discover, yet most of us simply do not see in the true sense of the word. However, when it comes to observing faults in others, most of us are are quick to react with condemnation. But what about looking inwardly for a change? To personally examine who we really are and what we are, our merits as well as our faults — in short, to see oneself as [one] is for once and to take responsibility [for] oneself.

“In My Own Process,” Draft 8 (Courtesy of the Bruce Lee Foundation archive)

In the penultimate draft, he turns from the intellectual dimension of self-knowledge to its emotional rewards:

I am happy because I am daily growing and honestly not knowing where the limit will yet lie. To be certain, every day can be a revelation or a new discovery. However, the most satisfaction is yet to come to hear another human being say, “Hey, here is something real.”

He touches on the deeper significance martial art held for him as a spiritual practice and not the merely the decorative performance Hollywood made it out to be:

By martial art I mean, like any art, an unrestricted expression of our individual soul… The human soul is what interests me. I live to express myself freely in creation.

Bruce Lee (Photograph courtesy of the Bruce Lee Foundation archive)

Lee’s reflection on what it means to be a great actor applies equally to every art, as well as to the art of life itself:

An actor, a good actor that is, not the shallow stereotyped artist, is an ever-growing process of learning, expansion and constant discoveries… To be of quality in acting means … lots of painful hard work and lots of undivided dedication to practicing what one believes.

“In My Own Process,” Draft 9 (Courtesy of the Bruce Lee Foundation archive)

In the ninth and last draft — which is still a draft, for his untimely death intercepted the completion of the piece — Lee reassembles the mosaic of the intellectual, spiritual, and emotional dimensions of selfhood, and returns to his central ethos of personal authenticity:

Where some people have a self, most people have a void, because they are too busy in wasting their vital creative energy to project themselves as this or that, dedicating their lives to actualizing a concept of what they should be like rather than actualizing their potentiality as a human being, a sort of “being” vs. having — that is, we do not “have” mind, we are simply mind. We are what we are.

Complement with Lee on self-actualization and the crucial difference between pride and self-esteem and the philosophy and origin of his famous water metaphor, then hear Shannon Lee discuss her father’s work on “In My Own Process” with cohost Sharon Lee in this episode of the excellent Bruce Lee Podcast:


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