Gregg:

Well, what did Mr. Duhigg find for you?

What I found was: "But I was born with the speculative instinct and I did
not want that temptation put in my way." (Notebook 32, TS p. 14, cited in
_Mark Twain's Correspondence with Henry Huttleston Rogers_, 337n1). 'Tis a
poor thing, but 'tis mine own.

I do have a feeling that, like the punch lines to jokes that appear over
and over in his notebooks, Clemens probably expressed his awareness of his
inclination to speculate many times, in many places--though not often
enough, one might say.

You do come up with interesting requests for help.

Ken