As promised in my last post, here is evidence of another one of the four films based on The Master Mystery – The Doctor’s Vengeance.

The first ads that I could find are from January, 1921:

[The Public Ledger (Maysville, Kentucky)]

I also found some ads from March 1921:

[Witchita Daily Times (Wichita Falls, Texas)]

May 1921 is the last time I could find an ad for the picture.

[The Houston Post (Houston, Texas)]

Next week:

• Lost Houdini Film(s) Based on The Master Mystery – Mystery Solved