FAMILY SECRET July 21, 2007 -- A NEW biography of Cornelius Vanderbilt reveals a deep, dark secret the American railroad tycoon carried to his grave - he had an unquenchable thirst for hookers and succumbed to a debilitating sexual disease. In COMMODORE: THE LIFE OF CORNELIUS VANDERBILT, due in October from Basic Books, author Edward Renehan Jr. says the patriarch of the famed Vanderbilt dynasty suffered and died from an advanced case of syphilis in 1877. ‘He contracted it during a long career of frequenting waterfront whores in downtown New York,’ the author told us.