Paul Ehrlich: The Magician of Medicine
He opened the door to a way of thinking about disease treatment
One hundred and seventy years after his birth, Paul Ehrlich should still be celebrated, although perhaps the average person is none the wiser about this pioneer's great achievements and contributions to humanity. Ehrlich, the discoverer of the famed "magic bullet," the man who brought us Salvarsan, the first effective treatment for syphilis which was at that time one of the most lethal and infectious diseases in Europe. His treatment, known as compound number 606, was named "606" from the fact that it was the 606th compound tested by Ehrlich and his team in their search for a successful antimicrobial agent. He is commonly portrayed in the guise of an alchemist, someone who methodically tested hundreds of compounds to find the right one. But if this conjures an image of a curious, slightly obsessive mad scientist in a lab coat, it misses the larger, more profound story of Ehrlich. Ehrlich wasn't just a chemist; he was a biologist in the deepest sense, an explorer of life's mysteries, both human and microscopic. His contributions were recognized with the Nobel Prize in Physiology or Medicine in 1908, awarded for his work on immunity alongside Élie Metchnikoff. He elucidated not only what he worked on, but also the very nature of what it means to explore.
Ehrlich was born to an innkeeper in Strehlen (Strzelin), a small town in Silesia, in modern day Poland, in 1854. His youth was unremarkable, except for a fondness for Latin, enough to pepper his daily conversations with Latin phrases, an oddity that hinted at an eclectic spirit. He seemed destined for the ordinary, but then came chemistry, dyes, and a cousin named Carl Weigert, who introduced him to tissue and bacteria staining. Those colors caught Ehrlich's imagination and held it fast, becoming the means by which he would understand the vibrant, unseen world.
Technique
By injecting dyes into living organisms, Ehrlich did something radical, he sought to see what the eye could not, to reveal hidden affinities. His early work made it possible to differentiate cellular components of blood, laying the foundation for modern hematology. Yet Ehrlich wasn’t interested in dyes as mere spectacle, for him, they were a way to expose life's fundamental chemical relationships. Why does one tissue stain blue and another red? Why do certain bacteria absorb certain dyes and not others? Ehrlich thought deeply about such questions, and these were no superficial musings, they led him to understand the very notion of chemical affinities, an insight that would guide him in developing the first effective treatment for syphilis.
The popular science imagination likes to think of Ehrlich as the discoverer of a "magic bullet", a therapeutic agent that could selectively target and kill pathogens while sparing the host. In his day, this idea must have seemed an almost mystical proposition, akin to turning lead into gold. Yet, Ehrlich's genius lay in grounding such seemingly magical aspirations in the realities of biology and chemistry. Ehrlich's practicality wasn't about mundane or selfish concerns, instead, it was a more inspired and aspirational type of practicality, aimed at advancing science and medicine. In the end, Salvarsan, his so-called magic bullet, wasn't perfect. It was cumbersome to administer, required multiple treatments, and came with side effects, not the one-shot elixir he had hoped for. But it was something greater, it was a proof of concept. It opened the door to a way of thinking about disease treatment that has shaped medicine ever since.
Work Ethic
One might ask, what drove Ehrlich to pursue this path? He wasn't motivated by the promise of fame, nor by the conventional rewards of medicine, the glory of being a healer. If anything, his motivations seemed rooted in a restless need to interrogate nature, to ask, as Goethe's Faust did, what holds the world together in its inmost folds. His career was defined by toil, a Faustian pursuit of knowledge that sought to unravel the chemical basis of immunity and disease. And perhaps that’s why Ehrlich’s story should resonate today. His spirit, untidy, obsessive, and profoundly curious, feels like a challenge to the reductionism that often accompanies our conversations on progress.
There is something inspiring in Ehrlich’s willingness to start from the foundation, to question even the most basic assumptions about how to treat disease. His "side-chain theory" of immunity, with its talk of antigens, antibodies, and receptors, might have sounded almost alchemical to his contemporaries. It drew skepticism, and yet it provided a conceptual framework that helped birth immunology. Ehrlich knew that understanding was never complete, that every answer merely leads to new questions. He was deeply aware of his own limitations, not just as a scientist, but as a human being. He knew that the medicines he created were far from perfect; he foresaw future chemotherapies that would one day make his own work look rudimentary. He was not content with the discovery of diphtheria antitoxin; he needed to understand the mechanism, the "how and why" of its function.
Keep Trying
Is there a lesson here for us? Progress, it seems, is rarely about perfection. It is often about the messy, laborious, and sometimes deeply flawed pursuit of something greater, a pursuit that might require 606 attempts, but which is driven by the conviction that each failure brings us closer to an answer. Today, Ehrlich might tell us not to chase the illusion of a flawless magic bullet, but rather to appreciate the beauty of each partial solution, each new insight that brings us closer to understanding what we are really made of. His work was not the end, but the beginning of a conversation, one that we are still having, and must continue to have, about the nature of disease and of life.
Medical Visionary
Between 1850 and 1915, the emerging scientific disciplines of chemistry, biology, physics, and medicine witnessed extraordinary progress driven by the remarkable contributions of numerous brilliant scientists, such as Louis Pasteur, Rudolf Virchow, Ilja Iljitsch Metschnikow, Carl von Rokitansky, Robert Koch, Karl Landsteiner, Emil von Behring, among others. In this climate of pioneering discoveries and achievements, Paul Ehrlich emerged as a prominent and influential researcher, helping to lay the foundational groundwork for the fields of hematology, immunology, pharmacology, and chemotherapy.
Paul Ehrlich was not simply a chemist or biologist, he was a medical visionary. An idea that progress is not neat, that discovery is not instantaneous, and that every endpoint is simply a new starting point. His tireless industry, kindness, and modesty are well-documented by his former secretary, Martha Marquardt. She vividly described his lifelong habit of eating little, smoking 25 strong cigars a day (often carried under one arm), and his insistence on rigorously proving his results through repeated experiments. The street where his Institute was located in Frankfurt was named Paul Ehrlichstrasse in his honor, but this was later revoked during the Jewish persecution. Yet, after World War II, when his birthplace of Strehlen came under Polish jurisdiction, it was renamed Ehrlichstadt in tribute to their great native son.
If we remember Ehrlich today, it should not only be for the discovery of Salvarsan or his Nobel Prize awarded in 1908, but for the spirit of his questions. Questions that still drive us forward, urging us to look deeper, to ask what remains unseen, and to keep seeking answers, however many attempts it might take.
Stay curious
Colin
This is part of a series of classic scientists, and books about, or by them, that I think should be widely read to help us have a better understanding of the world we live in, and of each other. Others in the series are:
Many more to follow.