] I take "a neighborhood of voluntary spies" to mean that in any small town or village there are no secrets. Everybody knows everybody else's business - you cannot help it, living in close society and seeing the same people all the time.

I'll confess that I can never read Henry's speech without thinking of a much later piece of literature: one of the Sherlock Holmes stories by Arthur Conan Doyle, in which Holmes confesses to Watson that he is, at times, horrified by the possibilities for crime at an isolated country estate where, to borrow a movie tag, "no one can hear you scream." No, it would not be the same as a rural village, where there is indeed that "neighborhood of voluntary spies," but it's interesting to me how in so many ways people seem to consider crime as a feature exclusive to large cities.