Only an observation today to satisfy our curiosity.  Details and conclusions and error-checking will come in the weeks ahead.  These words appear in the 1937 Chapter 5 of The Hobbit and do not appear in the 1951 edition, the one with which we are most familiar:

croaking   daresay   durstn’t   findings   flip-flap   funnily   fuss   good-bye   jags   politely   recklessly   shuddered   slipping   sneak   sometime   spluttering   squeeze   unsuspecting

My goodness!  “Funnily” and “good-bye” and “politely”!  what a different feeling.  Here follow those words which were added in our 1951 edition.  I have included links for those which have entries in the Concordance or other posts:

back-door   backwards   Baggins   betterment   birthday-present   blindly   blood-curdling   bowstring   brooded   cracking   crawling   creepsy   crouched   cursing   dursn’t   eyeses   flapped   flattened   forefinger   galled   gleamed   gnaw   goblin-imp   goblinses   groping   guesses   gurgling   hates   hiding-place   hiss   hissed   hissing   humped   iss   jagged   leapt   losst   maddened   menacing   menacingly   mouse   musst   nassty   noser   nosey   oddments   orcs   paddling   palely   pang   panted   peered   pinch   pocketses   pouch   pricked   quicker   screech   shambling   sharpened   sharper   sheathed   shiver   shivering   shriek   shrieked   shrieking   side-passages   slide   slimy   sloping   smells   smelt   snag   sneaking   sniffed   softer   splayed   squeaked   squeaker   squeaking   squeezes   ssorry   ssss   stab   stiffened   swayed   tense   tricksy   tripping   tunnel-wall   tunnels   unlost   unmarked

Please do note that both editions have “ss”, “sss”, and “sssss” in them – it’s just four esses, “ssss” which is unique to the 1951.  So many things to say about these words, but I had better save it for another day, in the morning after coffee when I’m fresh.