I don't know if this is the place to get the best answers to this question, but hopefully someone here can help me. Why is it that, when writing out full names, some authors, especially in the 19th century, have a tendency to run a line through all but the first letter of he name? For example, in Jules Verne's "Five Weeks in a Balloon," Verne spells out completely the name of Dr. Samuel Ferguson, but names the president of the Royal Geographical Society as Sir Francis M----. Similarly, Poe has many poems titled as "To M---" or "To F--S S. O--D."
Hopefully, someone can provide some insight for me, whether through explaining it as individual quirks of the authors or enlightening me as to what changed between then and now that the practice fell out of fashion.
It was a practice supposedly for anonymity, or at least tact; you'll also see a common practice where part of the date is left out, as in "192-". Many writers of the 18th-20th century wrote with the narrative pretense or framing device that their works were true stories, however uncanny, and that they were merely relating the tale - it was a way to help the reader suspend disbelief (and, if they referred to real persons, a way to avoid being sued). John Barth in "Lost in the Funhouse" [PDF] (1980) specifically calls attention to it:
Initials, blanks, or both were often substituted for proper names in nineteenth century fiction to enhance the illusion of reality. It is as if the author felt it necessary to delete the names for reasons of tact or legal liability. Interestingly, as with other aspects of realism, it is an illusion that is being enhanced, by purely artificial means.
Other authors would go into detail about how the names they used were not the actual names of those involved - for example, pulp writer A. Merritt in "Three Lines of Old French" (1919) wrote:
There were four of us in front of the fireplace of the Science Club - Hawtry, who rules the chair of psychology in one of our greatest colleges, and whose name is an honored one throughout the world; Latour, an immortal of France; McAndrews, the famous American surgeon whose work during the war has written a new page in the shining book of science; and myself. These are not the names of the three, but they are as I have described them; and I am pledged to identify them no further.
This was a not-uncommon practice at least as late as the 1950s, when the television show Dragnet would assert that:
Ladies and gentlemen, the story you are about to see is true. The names have been changed to protect the innocent.
It's tricky to say why it fell out of fashion without going into speculation; the rhetorical and literary device of a "true relation" where the details of who is involved are obscured appear to have fallen out of favor as stories tended to get more direct - at least in the area of popular fiction - with pseudonyms and aliases find better favor than blanks. This was, at least, the case with many "confession" style pulps.