George Minot’s education at Harvard Medical School was on the modern side of this revolution in medical education. The first lecture he sat through was on manners and the appropriate way to dress. But after that, it was lectures on anatomy and histology, within a few weeks he started a dissection of a human body. The first year courses included physiology and biological chemistry. His second year courses included pathology and bacteriology, before he was introduced to patients. His instructors included Otto Folin, who developed many different blood and urine tests; Walter Cannon, who developed the method of feeding patients special mixtures of x-ray absorbing food to allow x-ray imaging of the digestive tract, and Lawrence Henderson who described how blood could maintain its pH level even when lactic acid is released into it.
At the end of the third year, the students had a series of examinations, a precursor to today’s shelf exams. These exams consisted of a series of eleven exams, given one each weekday over a two week period. The fourth year courses met in different hospitals and trained the students in practical medical care: taking medical histories and performing physical examinations. George Minot graduated from Harvard Medical School in 1912, along with fifty-four other men.
George, along with eleven other graduates, all wanted to be one of the six House Pupils that Massachusetts General Hospital was hiring for the next year. A House Pupil, today these positions are called “interns”, is a doctor who is in the first year of a residency training program. The hospital held an interview, which was more of an oral examination, for each of the twelve applicants. The interview was in front of the selection committee, four physicians who were on the staff of the hospital. George’s father was one of the four. Unsurprisingly, George was selected for the position, along with his classmate, cousin, and close friend Francis Rackemann. For George’s first real job, he was hired by his father.
The Massachusetts General Hospital is located in Boston, only about a mile from the house where George’s family lived. He had spent his whole life in this section of Boston. The furthest of the schools he had attended was Harvard College and that was about 3 miles from his home, a distance you could walk in about an hour.
This training program at the MGH took 16 months. It progressed through four positions of increasing responsibility, each four months long. The second position, called “pup,” was responsible for the laboratory tests. The pup measured the amount of sugar in urine, looked at blood smears in a microscope, and even grew cultures of typhoid each night (used in the Widal test to diagnose typhoid fever). The pup was helped by the man in the first position, the “sub pup”. The fourth position, called “senior”, was responsible for the care of his section of the hospital. The hospital had two sections, the East and West Medical Services. Each had about 60 patients. A visiting physician did morning rounds with the senior to check on the care of patients, but at all other times the senior cared for the patients.
At MGH, George also witnessed the maturation of x-rays as a diagnostic tool. The man who ran the x-ray department at the hospital was Walter J Dodd. Dodd had started at the hospital in the apothecary, as a chemist. But when Roentgen published his discovery of x-rays, in 1896, Dodd had adopted a role as the Hospital’s x-ray expert. Dodd acquired vacuum tubes and built his own x-ray machine. Unfortunately, his pioneering work was done before the dangers of x-rays were understood. He had visible deformities due to frequent exposure to x-rays. His face was marked by burns and scars, his hands were missing parts of his fingers. He had undergone 50 different surgical procedures to treat his burns. He died early, at the age of 47, in 1916, of metastatic lung cancer almost certainly from multiple primary radiation cancers caused by overexposure to x-rays.
After his stint at MGH, George’s career was at a crossroads. He could pursue a conventional career in medicine: open up an office and begin seeing patients, like his father. Or, he could pursue a career in research. At the time, research in medical schools was mostly on basic sciences, subjects like physiology and anatomy. MGH had created a new position and hired a new man to begin a research program, Dr David Edsall. Clinical research was absent from most hospitals. George had worked within the structure at MGH, and he was really too busy there taking care of patients to engage in any serious research. There was one place, however, in the United States where clinical research was possible: Johns Hopkins University in Baltimore, Maryland. Dr David Edsall made arrangements and George was offered a position there.
He started in Baltimore at the beginning of January 1914. His responsibilities were initially similar to those at MGH. He oversaw the medical care for patients. That position lasted through the end of September, then he began doing research. Minot was interested in blood, and he was introduced to research by Dr William Howell. Howell was conducting research on the coagulation of blood. Blood outside of the circulatory system quickly forms a clot, while blood in its natural environment does not. George only worked with Howell for a few months, long enough to learn some basic laboratory techniques.
Howell, over several years, showed that blood contained two factors related to clotting: thrombin, which was already known, and anti-thrombin, which was not. At first, he was unable to isolate anti-thrombin, but through careful experiments he inferred its presence and that it originates in the liver. Two years after Minot left his laboratory, a medical student at Johns Hopkins named Jay McLean working in Howell’s laboratory isolated the “anti-thrombin” from a dog’s liver cells. Howell named the substance heparin. Heparin is still used medically today both as a drug to reduce the risk of blood clots forming and as a treatment for blood samples being sent to a laboratory.