comedy humor literature uncle tom's cabin

Ok, got bogged down last time.

My overall topic is: how does humor function in Uncle Tom's Cabin? I'm not theorizing on the difference between characters in comedies and characters with comedic attributes in serious works. 

One principle of the theory of humor which I am constructing is that a work may be humorous in nature, or a work may be non-humorous ('serious', is too value-laden a term) but with comedic elements. (Likewise, there are tragic works and tragic elements in non-tragic works; adventure stories can have tragic and comedic elements without being either comic or tragic overall).