A Psychical Invasion — Algernon Blackwood

Dr. Silence was a free-lance, though, among doctors, having neither consulting-room, bookkeeper, nor professional manner. He took no fees, being at heart a genuine philanthropist, yet at the same time did no harm to his fellow-practitioners, because he only accepted unremunerative cases, and cases that interested him for some very special reason. He argued that the rich could pay, and the very poor could avail themselves of organised charity, but that a very large class of ill-paid, self-respecting workers, often followers of the arts, could not afford the price of a week's comforts merely to be told to travel. And it was these he desired to help: cases often requiring special and patient study -- things no doctor can give for a guinea, and that no one would dream of expecting him to give.  (Jacketless library hardcover.)