Just be chance I have been reading the letters on the Mark Twain
Project's site and I came across the one regarding his breaking
quarantine in Spain.  The explanatory notes provided by the Project
have a recapitulation of the missing Spain chapter/


https://www.marktwainproject.org/xtf/view?docId=letters/UCCL00152.xml;style=letter;brand=mtp#an2


On Sat, 2020-03-14 at 14:08 -0500, Barbara Schmidt wrote:
> The chapter on Spain that was deleted from INNOCENTS ABROAD is in the
> Vassar College Special Collections, Folder 27-A, pp. 1289-1331.
> 
> Barb