Quarantines, masks, death-terms familiar to anyone who faced the so-called Spanish Flu of 1918. World-wide, it is estimated that the horrifying influenza killed more than 50 million people, significantly more than did the guns of the Great War, which was just then coming to a close. And yet no one has ever heard from Sherlock Holmes or Dr. Watson concerning their own experiences surviving the terrible virus-until now. In a recently-discovered manuscript,...