In 1895, she began medical studies at the
University of Michigan; she earned her
Doctor of Medicine degree in 1898 and
Bachelor of Science degree in 1899. Lydia and Alton DeWitt separated during this time. DeWitt remained at University of Michigan for the beginning of her career in research. She held a position under George Dock as a demonstrator of anatomy from 1896–97, while she was still studying medicine, then became an assistant professor of
histology until 1902, and associate professor of histology from 1902–1910. She took a brief sabbatical to study at the
University of Berlin in 1906. That year, she was starred in the first edition of
American Men of Science for her notable work in
microscopic anatomy and
neuroanatomy. In 1910, DeWitt began to work at
Washington University in St. Louis as an instructor of pathology, and also took a post in the
St. Louis Department of Health as a pathologist/bacteriologist. Her research there was so noted that she was invited to join the faculty of the
University of Chicago to work on chemotherapy for
tuberculosis, which she did in 1912. She was an assistant professor of pathology there until 1918, when she was elevated to associate professor. She retired in 1926. As a woman scientist, DeWitt was excluded from the Faculty Research Club and the Junior Faculty Research Club at the University of Michigan. In response, she founded and headed the Women's Research Club in 1902. DeWitt's research career covered a variety of topics and organ systems, including the pathology of
tuberculosis. She studied
muscles extensively, in their pathology and nervous connections, as well as the disease
myositis ossificans. Other topics of her research included
esophageal anatomy, membranous
dysmenorrhea, and the anatomy of connections in the
mammalian heart. Her early research, at the University of Michigan, concerned the structure of nerve endings in both
sensory nerves and
motor nerves of
striated muscle and
smooth muscle. This also included studies of
muscle spindles, which were published in 1897, before she finished her medical studies. Her first solo research was published in 1901 and concerned the
pyloric glands and their structure in different species. While at the St. Louis Department of Health, she conducted extensive research on
diphtheria and diagnosis of
typhoid. Her work on isolating the
islets of Langerhans cells from the
pancreas and her discovery that they secreted a substance involved in
carbohydrate metabolism set the stage for the discovery of
insulin and its role in
diabetes by a Canadian team of researchers. At the University of Chicago, DeWitt and her team worked on developing a drug to treat tuberculosis based on the work of
Paul Ehrlich, who developed a treatment for
syphilis by chemically modifying a dye that would stain parasites. Working with
Hope Sherman,
Gladys Leavell, and
Lauretta Bender, among others, DeWitt examined several dyes as potential precursors to an anti-tuberculosis drug, including
methylene blue and
trypan red. This research did not bear fruit immediately, though the method was later used successfully to develop a chemotherapy for tuberculosis, and as a model for developing other drugs. ==Honors==