A hutkin, a cover for a sore finger. The Germans call a thimble a finger-hut, where hut is evidently the word hut or huth (a tending, keeping, or guarding), from the verb huten (to keep watch over). Our hutkin is simply a little cap for guarding a sore finger. Stall is the Saxon stæl (a place), whence our stall, a place for horses.
Source: Dictionary of Phrase and Fable, E. Cobham Brewer, 1894
More on Finger-stall from Infoplease: