Text: Now, if it had been lost and recovered, Mrs. Inglethorp would at once have replaced it on her bunch; but on her bunch I found what was obviously the duplicate key, very new and bright, which led me to the hypothesis that somebody else had inserted the original key in the lock of the despatch-case."
Entailment: She had to put a new key on her bunch.
Contradiction: She was still using the old key.