A cautionary tale on the known quantity

I've seen this attributed to Aesop as well as Ambrose Bierce, and I find it again and again with the concluding line as "I already knew that you were a skunk," but I prefer the version in a print copy of Ambrose Bierce witticisms that concludes as below:

  A Needless Labour


  AFTER waiting many a weary day to revenge himself upon a Lion for some unconsidered manifestation of contempt, a Skunk finally saw him coming, and posting himself in the path ahead uttered the inaudible discord of his race.  Observing that the Lion gave no attention to the matter, the Skunk, keeping carefully out of reach, said:

  "Sir, I beg leave to point out that I have set on foot an implacable odour."

  "My dear fellow," the Lion replied, "you have taken a needless trouble;  I already knew that you were not a rose." 

I love Ambrose Bierce.  How did anyone get to be so cynical before there was the internet or an IRS?