Jacobs left Massachusetts General Hospital in spring of 1888. He then became a physician at the Boston Dispensary and started a general medical practice at 8 Hancock Street in Boston. He was a member of the board of managers of the Maryland State Tuberculosis. He was secretary of the National Association for Prevention of Tuberculosis from 1904 to 1920. He also served as director. Jacobs was a member of the International Association for Prevention of Tuberculosis. Jacobs wrote "Some Distinguished American Students of Tuberculosis" and articles on hygiene. In 1911, Jacobs was elected as a trustee of
Johns Hopkins Hospital. He also served as a trustee of
Peabody Institute. He was a fellow of the
American Association for the Advancement of Science. Jacobs served as vice president of the
Baltimore Museum of Art and became president in June 1936. He was member of the executive committee of the Baltimore Society of the Friends of Art. Jacobs was a collector of medical portraiture. He was president of the Johns Hopkins Medical Historical Society. He was a member of the Medical Historical Society of Paris and was an associate editor of the Annals of Medical History. Jacobs spent summer months of his life in
Newport, Rhode Island, starting in 1890. He served on the executive committee of the Newport Art Society. He served as president of the Spouting Rock Beach Association. He also served as secretary and treasurer. Jacobs was president of the
Redwood Library from 1931 to 1939 and governor of the
Newport Casino. He was also vice president of the Newport Improvement Association. He was one of the first members of the board of managers of the
Seamen's Church Institute of Newport. ==Personal life==