“The Secret of the Su” was published in November 1943. The inspiration for “The Secret of the Su” came from a newspaper article. Dr. George Sperti was part of an expedition into the Florida Everglades seeking plants that could replace the products now denied the United States because of World War II.
In an undated letter from early 1943, Doc Savage editor John Nanovic writes to Lester Dent acknowledging receipt of a Doc Savage story. Nanovic also included a newspaper clipping about a scientific expedition into the Florida everglades to discover new drugs. This will be “The Secret of the Su” which was published in November 1943.
Nanovic included some colorful ideas for plot development along this line:
“Also enclosing clipping for an idea on another. How about having Doc get the job of going into the Everglades for this medical stuff, and there he meets trouble. See what it might suggest: enemy submarine base (too far-fetched); some simple hide-out of crook; undercover headquarters of spies; or just plain trouble with natives, etc.
Below is a copy of the article Nanovic sent to Dent. The original that is in the Western Historic Manuscript Collection has a different layout and is probably from the New York Herald-Tribune. We can conclude from the article’s date, February 5, 1943, that Nanovic’s letter to Dent was sometime before this.
The United States was in the midst of World War II when this article appeared. Vital materials traditionally imported from Asia were now unavailable. Substitutes had to be found. Dr. George Sperti, director of the Institutum Divi Thomae, was the head of an expedition into the Florida everglades to seek new plants and materials that could replace these vital items.
Items of interest to the scientist were replacements for quinine, agar, and native herbs for the treatment of dysentery. Quinine is used to treat malaria. Agar is a sugar used to culture specimens for biological research. Prior to the war, most agar came from Japan.
Scientists in the expedition believe the natives Seminole tribe have some useful knowledge about the various medical uses of the local plants.
All these ideas about vital medical discoveries waiting to be discovered in the vast Florida Everglades provided Lester Dent with more than enough material for “The Secret of the Su.” In Dent’s story, the Su are a reclusive tribe secretly living in the Florida Everglades. Their secret is an herb with miraculous healing powers. It is explained how this new drug will save the lives of American soldiers. Doc Savage and his men battle a criminal gang along the way who plans to capture the secret and then cash it in for big bucks.