Leon O. Jacobson

Leon O. Jacobson was Associate Director of the Health Division and Section Chief of H-I, Clinical Medicine and Medical Research, at the University of Chicago's Metallurgical Laboratory ("Met Lab") during the Manhattan Project. 

Beginning in 1944, Jacobson served as the Associate Director of the Health Division and the Section Chief of H-I, Clinical Medicine and Medical Research. He worked under Director of the Health Division, Robert S. Stone. During World War II, he was also a consulting physician at the University of Chicago's Toxicity Laboratory, where he worked with chemical warfare agents and developed forms of protection against them.

Early Years

Leon Orris Jacobson was born in Sims, North Dakota on December 16, 1911. Jacobson initially saw himself studying agriculture and continuing the family tradition of ranching in North Dakota. The Great Depression, however, led to economic troubles and he stopped his agriculture studies during his second year at North Dakota State University. 

To earn money, Jacobson taught eight grades at the elementary school in Sims for three years. While teaching at the school and observing children coming down with various illnesses, Jacobson became interested in medicine.

In 1935, Jacobson graduated from North Dakota State University. For medical school, he decided to apply to only one school, the University of Chicago. He graduated from the University of Chicago's medical school in 1939 and stayed at the University for his internship and residency. Jacobson became an instructor in the Department of Medicine in 1942.


Later Years

From 1945 to 1948, Jacobson worked as an assistant professor of medicine at the University of Chicago. In 1948, he was promoted to associate professor and continued to hold that position until 1951. During this period, he also served as the associate dean of the Division of Biological Sciences and the School of Medicine at the University of Chicago.

In 1951, Jacobson was appointed as Professor of Medicine, Head of Hematology, and Director of the Argonne Cancer Research Hospital. The Argonne Cancer Research Hospital was designed to be a clinical research institute with research beds and laboratory space. The hospital specifically researched how nuclear medicine could be applied to cancer-related problems and developed into therapies.

Jacobson became the chairman of the University of Chicago's Department of Medicine in 1961, the Joseph Regenstein Professor in 1965, and the dean of the Division of the Biological Sciences and Pritzker School of Medicine in 1966. He became a professor emeritus in 1976, but did not retire until 1981.

At the age of eighty, Leon Orris Jacobson died on September 20, 1992 in Chicago, IL.


Scientific Contributions

At the Toxicity Laboratory, Jacobson studied nitrogen mustards and their effects on hemopoiesis. Using his research knowledge, he began to study the clinical applications of nitrogen mustard for cancer therapies in 1943. The treatment ultimately proved effective for treating Hodgkin's disease and providing a lasting remission.

While at the Met Lab, Jacobson focused on recovery from radiation injury. His experiments on the effects of ionizing radiation on hemopoiesis in mice led him to the conclusion that the blood-forming system was one of the most sensitive to radiation. During this period, Jacobson began to work in the fields of erythropoietin and erythropoiesis within hemopoiesis.


For more information about Leon O. Jacobson, please see the following references:

Leon O. Jacobson's Timeline

  • 1911 Dec 16th Born in Sims, North Dakota.
  • 1935 Graduated from North Dakota State University.
  • 1939 Graduated from the University of Chicago's medical school.

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