L. Frank Baum,
Mary Louise Solves a Mystery — Chapter XIX. ON THE TRAIL
(1917)
“ You can't open a mystery as you do a book, Mary Louise; it has to be pried open. The very fact that this Mrs. Orme has so carefully concealed her hiding- place is assurance that she's the guilty party who abducted Alora. Being positive of that, it only remains to find her—not an impossibility, by any means—and then we shall have no difficulty in liberating her prisoner. ”
