Arrowsmith by Sinclair Lewis

Through the storm of his Christmas examinations, Martin had an intensified need of Leora. She had been summoned home to Dakota, perhaps for months, on the ground that her mother was unwell, and he had, or thought he had, to see her daily. He must have slept less than four hours a night. Grinding at examinations on the interurban car, he dashed in to her, looking up to scowl when he thought of the lively interns and the men patients whom she met in the hospital, scorning himself for being so primitive, and worrying all over again. To see her at all, he had to wait for hours in the lobby, or walk up and down in the snow outside till she could slip to a window and peep out. When they were together, they were completely absorbed. She had a genius for frank passion; she teased him, tantalized him, but she was tender and unafraid.

He was sick lonely when he saw her off at the Union Station. His examination papers were competent but, save in bacteriology and internal medicine, they were sketchy. He turned emptily to the laboratory for vacation time.