Imaginary man.
his "Imaginary man" could possibly refer to the "French gentleman" in Mr. Venus's shop, but it most likely refers to Mr. Venus himself, an imaginary version of the taxidermist Mr. Willis, to whom illustrator Marcus Stone took Dickens for inspiration (see note above). In a letter to Stone on Februrary 28, 1864, Dickens wrote: "I have done the St. Andrew Street place, and have made it the last Chapter of the 2nd. No. I will send you a proof when I get it. It is very like, with an imaginary man and an imaginary place in the story." The full text of this letter is available on the Our Mutual Friend Scholarly Pages (University of California Santa Cruz) at http://omf.ucsc.edu/dickens/letters/marcus-stone.html.