What is the theme in Arsenic and Old Lace by Joseph Kesselring?

Loyalty is another theme in this book. Loyalty – sometimes misplaced – is central to the plot of this play, and is exhibited in one form or another by the major characters. Abby and Martha are fiercely loyal to Teddy – to the point of being willing to commit themselves to a sanitarium to remain with him – while Mortimer is willing to go to any lengths to cover up his aunts’ crimes. Elaine remains loyal to Mortimer, even though he spends most of the play either ignoring her, or throwing her out of the Brewster house. Even Dr. Einstein – although he does what he can to keep him from committing further murders – remains loyal to Jonathan. Jonathan is the only major character who does not show some level of loyalty, and this is part of what makes the audience consistently dislike him.