A.J. Cronin's book "The Citadel" was adapted for a 1938 film starring Robert Donat, Rosalind Russell, Ralph Richardson, Rex Harrison, and Emlyn Williams, directed by King Vidor.
Donat plays Andrew, a young, idealistic new doctor who goes to work in a small Welsh mining town, where he marries a pretty schoolteacher, Christine (Rosalind Russell). Many of the miners have a persistent cough, and he becomes interested in finding the cause. But the miners have little understanding of the big picture and just want the "pink medicine" the old doctor gave them, which just helped their symptoms.
Thwarted at every turn, Andrew and Christine move to London, where Andrew opens a practice. Then he has a change of fortune when he runs into an old friend (Rex Harrison) who gets him on the society doctor track, where he gets big money for treating hypochondriacal patients and by merely being present while a surgery is being performed, or taking a referral.
A beautiful movie with the underrated Donat turning in a wonderful performance of quiet intensity. Russell's expressions say more than her words - you know exactly how she's feeling. Ralph Richardson -- was he ever bad? - plays Andrew's old friend Denny, who notices the change in Andrew's goals.
A.J. Cronin was one of the authors whose novels were often adapted for film in the old days: "The Spanish Gardener," "The Green Years,", "Keys of the Kingdom," "Bright Victory," "Vigil in the Night," and others. Some of his stories involve medicine/science and sacrifice/dedication. Those books made for some inspiring films in the '30s and '40s.