Who is Campbell from Collected Short Stories Volume Three and what is their importance? W._Somerset_Maugham English & Literature Campbell | Collected Short Stories Volume Three

Campbell appears in the story, Sanatorium. He is a patient at the Sanatorium, and he is also the person who has lived there the longest. Campbell believes that McLeod, another patient at the hospital, has the best room. Thus, he waits impatiently for McLeod to die or move out so he can have his room. As a way to frustrate the other man, Campbell plays the same tune on his violin repetitively.