He helped to plan the new Hunterian Laboratory for experimental surgery and medicine and improved the facilities for metabolic studies.
The Janeway firm of the Osler Residency program at Johns Hopkins Hospital is named after him.
In 1917, Janeway resigned his position at Johns Hopkins and entered the medical services of the U.S. Army, with the rank of Major.
He was assigned to the Office of the Surgeon General, where he became director of research on heart disease.
Their son Charles Alderson Janeway was an eminent American pediatrician, medical professor, and clinical researcher.