Sentence:  "Jeeves:" Foreign travel often <WSD>liberates</WSD> emotions best kept in check, sir. The air of North America is notoriously stimulating in this regard, as witness the regrettable behavior of its inhabitants in 1776./ "B. Wooster:" Hm? What happened in 1776, Jeeves?/ "Jeeves:" I prefer not to dwell on it, if it's convenient to you, sir. 
Meaning of the word marked with <WSD> tags:  To release from restraint or inhibition.