Arrowsmith by Sinclair Lewis

And always Martin's work went on-assisting Max Gottlieb, instructing bacteriological students, attending lectures and hospital demonstrations-sixteen merciless hours to the day. He stole occasional evenings for original research or for peering into the stirring worlds of French and German bacteriological publications; he went proudly now and then to Gottlieb's cottage where, against rain-smeared brown wallpaper, were Blake drawings and a signed portrait of Koch. But the rest was nerve-gnawing.

Neurology, O.B., internal medicine, physical diagnosis; always a few pages more than he could drudge through before he fell asleep at his rickety study-table.