In the Charles Neider edition of Twain' short stories (1957) there are some
letters and an editorial inserted in the middle of "A Double-Barreled
Detective Story." I know these insertions did not appear in Twain's first
publication; they were added later.  I am intrigued by the way they are
inserted in Neider's edition -- they really disturb the flow of the
narrative.
Finally, my question:  when were these insertions added to the text?  did
they
really appear in the Springfield _Republican_ in 1902 as cited in the Neider
edition?  who was responsible for first inserting them?
Any comments on this matter are greatly appreciated.  Thanks.

Albert Sears