In 1942, Sperry began work at the Yerkes Laboratories of Primate Biology, then a part of Harvard University. There he focused on experiments involving the rearranging of motor and sensory nerves. He left in 1946 to become an assistant professor, and later associate professor, at the University of Chicago. In 1949, during a routine chest x-ray, there was evidence of tuberculosis. He was sent to Saranac Lake in the Adironack Mountains in New York for treatment. It was during this time when he began writing his concepts of the mind and brain, and was first published in the "American Scientist" in 1952. In 1952, he became the Section Chief of Neurological Diseases and Blindness at the National Institutes of Health and finished out the year at the Marine Biology Laboratory in Coral Gables, FL. Sperry went back to The University of Chicago in 1952 and became an Associate Professor of Psychology. He was not offered tenure at Chicago and planned to move to Bethesda, Maryland but was held up by a delay in construction at the National Institutes of Health. During this time Sperry's friend Victor Hepburn invited him to lecture about his research at a symposium. There were professors from the California Institute of Technology in the audience of the symposium who, after listening to Sperry's lecture, were so impressed with him they offered him a job as the Hixson Professor of Psychobiology. In 1954, he accepted the position as a professor at the California Institute of Technology (Caltech as Hixson Professor of Psychobiology) where he performed his most famous experiments with Joseph Bogen, MD and many students including Michael Gazzaniga.