I am fearlessly reading the stupendous "Mark Twain Day By Day," and in volume 2 of the digital edition, I note that it contains the assemblage of letters ("isterine") in multiple (6) places. My hunch is that this is a global search-and-replace gone wrong, but I haven't figured out just yet what the replaced word or fraction of a word originally was.
Here are the occasions where it occurs:
0) saving it up, & isterine it, & making it last as long as possible
1) and I were isterine up and down the library 
2) Finally he said to Mamma in an isterine tone, 
3) recounted the isterine stories which each Knight 
4) He was such a isterine speaker 
5) Mch 16 Bottle isterine 1.00 Mch 17 Flax Seed .35 tot 1.35 


Does anybody know what I should replace (in my mind) when I come across "isterine"? "Punch, Brother, Punch with Care" does not quite seem to fit...
- B. Clay Shannon