Learning that he may receive a knighthood if St. Swithins can produce a medical breakthrough, Professor Loftus takes up Bingham's suggestion that they research plastic catheters but sacks him when he finds he has stolen the idea from a magazine and assigns Duncan to the research instead. Duncan can't quite get the experiment to work but when an irate Bingham blows the whistle on Collier making home brew in the lab and takes a journalist there, it's Bingham's attempt to sabotage the research that causes its success.

Dr. Aziz comes to join Duncan in his research but Duncan finds it hard to understand him. Aziz leaves but a preparation of his is given to McCorquedale, a racist, bigoted Scots patient, as a sedative. Once again Duncan finds it hard to read Aziz's instructions and the wrong dosage is given - turning the patient black. Aziz makes it clear he left, not because he felt he was bullied racially but he found the staff incompetent and impossible to work with.