The path that doctors follow in our training is a continuous challenge, it is walking a narrow university route that leads us to multiple hospitals where we are nomads in search of excellence. We have a thirst for knowledge that allows us to learn how to help our patients and provide us with an honorable way of living. In this route we try to maintain our personality, our illusions, but the objectives change during the training process until we finally achieve that long-awaited goal: to become a physician.

As a baby boomer physician educated in México and the United States of America I have wondered about the enormous differences that exist between the various generations of doctors with respect to professional training programs, update methods, and the individualized treating each of our patients and their families. Although almost all practitioners recognize the Hippocratic Oath¹ as the guide in our professional praxis that keeps us in a scientific and ethical settings throughout the accelerated changes in knowledge and human principles, - from the statement primum non nocere to artificial intelligence applied to medicine- during the last year’s changes happen at the speed of sound making it impossible for a doctor – no matter how bright he or she is- to keep fully up to date.^2-4

From our birth to the that day we graduate as medical specialists, we spend almost half of our lives acquiring knowledge and skills with the goal of saving lives. Even after that day, it is mandatory to continue studying to maintain that ability in our work and, of course, to maintain board certification. All of this requires hundreds of teachers throughout our lives.  As for my medical professors, I had many; from medical school to the hospitals where I did my training as a resident and fellow until I became a specialist. Most of them were excellent, demanding, updated in their knowledge, upright in their professional actions, and dedicated to teaching. Some had written relevant texts on medicine and/or research with international recognition. Like all medical students, I also had some very stupid professors like the one who argued with me -in the middle of a lecture-, that the Golgi apparatus was an organelle that was part of the cell nucleus. This was an argument that earned me my early expulsion as a histology instructor, and also prematurely opened my eyes to realize that having chosen to be a doctor meant a long and demanding path in which I would have to search for the true truth, confront small and great personalities, fall and climb to modify my own opinions for the benefit of my patients.

Fortunately, I had an incomparable mentor who broke my heart and taught me minute by minute, without schedule, day and night, regardless of whether it was a weekend or a holiday, cold or hot weather. That special educator who never had vacations or professional fees; that mentor was my patient; alive or dead. That patient who, with his/her dignity and suffering, were like thousands of open books where I could read everything about how to help them, how to cure them, how to learn to let them go, and of course, how to prolong their lives. This particular mentor became my best book where I was able to study paragraphs that illustrated the suffering of those people. It was a blessing, a fortune that continues to accompany me every day of my professional practice; a noble teaching that gave a special touch to my life goal; to become a medical professional.

During the first months at the school of medicine, students with almost zero economic resources took turns with the few available real bones to study the intricate details of the skeletal system. This pressing situation led a group of 4 young medical students to obtain a permit for just 25 Mexican pesos to obtain human bones from a common grave in the Dolores cemetery, in Mexico City. In a similar way to George W. Crile,⁵ we desecrated not one, but three graves to obtain our first three medical books: three skeletons that at one time were people with goals, with illusions and surely with family, friends, and enemies. Although these people were not our patients, with their bones they taught us anatomy in a unique exceptional way, at no more cost than a few coins. Once the anatomy class has been passed, we give away those bone-books to other students to facilitate their learning. It was like this, with an experience as a grave robber, as many years later I realized the enormous importance that patients have as teachers, like open books where valuable details of each one of the diseases can be scrutinized.

In anatomy class, every two students were assigned a complete human cadaver. This particular book that in life had family, work, goals and failures showed us the most intimate of his entrails. I still remember the days I spent dissecting that corpse preserved in formaldehyde; that peculiar and unpleasant smell at the beginning that as the days went by was like a perfume that invited me to study each of his monochrome corners that were not similar to the colorful illustrations in my human anatomy book. I wanted to dissect every corner of his sacred humanity, so that day by day we advanced a region or two. It was strictly forbidden to mutilate them or take part of their organs out of the amphitheater. However, the professor of dissections, a very elegant Arab surgeon, occasionally let us take organs to study at home. One night I took his heart and the great vessels to meticulously study them under the light of a pale old lamp. Three nights later I had finished what now looks like an illegal and frightening study. I perfectly understood each cardiac structure and function and decided to keep that heart for myself, which I had carried from house to house for a couple of years. One weekend, when I had to escape from one of those houses due to lack of payment, I forgot my twin heart under my bed. Only God knows the reason for this and where that vital organ ended up, which on the one hand had maintained the life of that corpse and on the other, had transformed me into a knowledgeable student of the cardiovascular system.

I could narrate my relationship with many corpses that were my book-mentors, but I will only tell you one more; a very special body. The first two months of my internal medicine residency I was assigned to the pathology department where we had to perform and assist in autopsies guided by pathology residents and/or pathologists. It was 2 a.m. and I was on duty when I received a call because there was a corpse coming from the intensive care unit with a history of gastrointestinal bleeding secondary to portal hypertension. All the cadavers that arrived at the pathology department had to be autopsied, so two residents got ready to perform the necropsy at dawn. Because I was the lowest-ranking resident, I was assigned the abdominal cavity, while the other resident was in charge of the skull and thorax. When opening the colon, I noticed some lesions in the cecum that in my ignorance I thought were due to amoebiasis, a common pathology in México. That morning we presented the findings to the head of pathology who - with that elegance characteristic of erudite teachers- branded us as ignorant and without hesitation made the diagnosis of malakoplakia of the colon, assuring that it would be the 7th case reported. Months later they published it without giving me any credit. This corpse motivated me to study all digestive pathologies, especially malakoplakia lesions.

I have seen a large number of patients die in the ICU and in the emergency room, less in the operating room or in hospital floors. I have only seen a couple of people die due to my mistakes and inexperience in the initial years of my professional practice. Both died due to not being able to manage the airway correctly at the start of anesthesia at the time when there was no oximetry or ETCO₂ monitoring, when the monitor screens were so small that no more than 5 QRS complexes were barely visible, and when we only have a simple laryngoscope for the best approach to the airway. They continue to be my mentors and day by day they remind me of the importance of a correct assessment of the airway, of overcoming difficulties with the skill or support of another colleague, and of course, of having up-to-date equipment.

Fortunately, the largest group of my mentors-books were those people-patients who throughout my training as a doctor listened to me, showed me their sufferings, wonderfully describing each symptom of their disease. Children, young people, adults and the elderly allowed me to integrate thousands of clinical histories, carefully examine their bodies, their injuries. Study their laboratory and cabinet exams to complete diagnoses and prescribe their treatments. Some patients let me operate on them as an obligatory part of my training. Others allowed me to go further and share their joys when they returned home. There, I learned that healing is a divine blessing that gives us the opportunity to understand people closely, to be their friends, part of their families.

There were two special patients who, similar to other patients, taught me that the practice of medicine is an exceptional compromise. They were two of my professors in the final stage of my residency whom I was fortunate to take care of them at the ICU. One was an erudite anesthesiologist who not only lectured me in the classroom and in the operating room, but also showed me the beauty of life, taught me a thousand tricks not described in textbooks, and on his deathbed left me the obligation to maintain myself updated and to continue teaching new generations. The other patient was the director of the hospital; from him I learned not only medicine, he taught me ethics, mysticism, and responsibility; guides that, like all the graduates of that hospital, defined my professional life forever.

Finally, I must mention two large groups of patients who have been mentors to almost all health professionals; the patients of the N1H1 influenza pandemic and those of the most recent SARS-CoV-2 pandemic that turned the planet upside down, affecting all governments, world economy and, of course, the health sector. In the first pandemic I had the opportunity to catch it and be inactive for a month. I learned the lesson. When COVID-19 appeared in December 2019, all workers in the health sector received many lessons from our patients. Of course, these two pandemics are two different; the last one longer and deadlier. Although many doctors died infected by this novel virus, the majority -especially the young doctors who worked directly with these patients- all learned diverse forms of prevention to reduce infections, virtual medical practice increased in all its aspects, hundreds of procedures in all specialties were modified, especially in emergencies, critical medicine, anesthesiology and first contact medicine.

Thanks to each one of these mentors-books that have unknowingly guided me on a long, arduous and beautiful route during my training and professional practice as a doctor.

I thank Bertha Ramírez-Gutiérrez MD, Patricia Calvo-Soto MD, and Ramón De Lille-Fuentes MD for reviewing this manuscript

1. Meskó B, Spiegel B. A Revised Hippocratic Oath for the era of digital health. J Med Internet Res. 2022;24(9):e39177.
2. Campbell AV, Chin J, Voo TC. How can we know that ethics education produces ethical doctors? Med Teach. 2007;29(5):431–436.
3. Grunhut J, Wyatt AT, Marques O. Educating future physicians in artificial intelligence (AI): An integrative review and proposed changes. J Med Educ Curric Dev. 2021;8:23821205211036836.
4. Weidener L, Fischer M. Artificial intelligence teaching as part of medical education: Qualitative analysis of expert interviews. JMIR Med Educ. 2023;9:e46428.
5. Crile G. George Crile. An Autobiography. Volume I-II. JB Lippincott Company.  Philadelphia. 1947.