Long words for Short Wednesday (2005/07/06)

According to AMBER, here are the longest words in the current collection of GKC books.

These are perhaps cheating, as they are merely hyphenated...

in-concentration-camp-concentrated-him
nine-thousand-nine-hundred-and-fifty-seven
real-world-politik-scientifically-studying
twelve-thousand-five-hundred-and-eighty-three

So here are the non-hyphenated longest words...

antivivisectionists
characteristically
congregationalists
constitutionalists
conversationalists
intercommunication
internationalising
internationalist's
misrepresentations
oversimplification
representationists
transcendentalists
transubstantiation