This 1944 painting by Jack McMillen was commissioned by the U.S. government for Walter Reed Army Medical Center as part of the Works Projects Administration (WPA) artists' program of World War II. It illustrates the historical function of the Forest Glen annex of the Walter Reed Army Medical Center as a holding and rehabilitation unit for medical patients, including psychiatric patients, during World War II.
This is a role the Forest Glen annex also played in subsequent wars. Psychiatric patients were identified, and to an extent stigmatized, by wearing maroon hospital clothing. For many years this painting was on display at the Forest Glen annex in Silver Spring, Maryland.
(from a
publication by the Borden Institute)

The painting is egg tempera on canvas and measures 7 by 10.5 feet. It now is on display at the museum.
I also found a website while searching for whatever I could find on the artist. It's the
New Deal Art Registry, a fun site to browse.