In a Study in Scarlet, after the piece about the Mormons in Slt Lake City the next chapter is something like "A resumptio of the Narrative of John Watson, M.D.".
During the opening page of The Man with the Twisted Lip Mary Waton refers to her husband as James.
In another story Dr. Watson is called "John H. Watson". Many fans think that the "H." stands for Hamish, because "James" can also be a nickname for Hamish... and *that's* why his wife called him James.