In the dark comedy, Arsenic and Old Lace, the steady build up of tension is frequently interrupted whit the use of humor. Beginning with acts such as Abbott and Costello, and episodes of "I Love Lucy," humor is often the result of a misunderstanding. In the movie, "Arsenic and Old Lace," the plot combines murder and insanity. "Arsenic and Old Lace," seemingly outlines a mystery or drama, however with the addition of misunderstanding, it becomes a comedy. The humor is drawn from the characters' relationships with one another as well as the characters themselves, being misunderstood.
The movie centers on two sisters, Abby and Martha, and their nephew Mortimer. The misunderstanding lies between the sisters and the townspeople. Abby and Martha are known as sweet, kind, and charitable, however, the town is oblivious to the sisters' hobby of poisoning old men and burying them in their cellar. There is even a misunderstanding with the sisters themselves, as they see nothing wrong with what they do, and make no attempt to hide it. Yet, the humor of the movie is when their nephew, Mortimer, finds the bodies, and is quite flustered to discover how his aunts treat it with such nonchalance.
Humor is also found in the misunderstanding between Mortimer and his Brewster family. Throughout the entire movie, Mortimer finds himself ashamed of his Brewster name. He discovers that his aunts keep twelve bodies in the basement. Mortimer also receives a visit from his lunatic brother John, who, like his aunts, murders people. While Mortimer discovers more about his insane family, he still must deal with his brother Theodore, who believes that he is president Roosevelt.
Finally, Mortimer commits his brother Theodore along with
his aunts to an insane asylum. He begins to wonder whether he should commit himself as well. The humor in this scene is at the very end of the movie when Mortimer finds out from his aunts that he is not really a Brewster, rather a son of a sea boat...