Continuity mistake: When Elmer pretends to be a rabbit, he jumps into a hole and there is a tree and a bush in the background. When Bugs tells him to come out of the hole, more trees and bushes have appeared.
Continuity mistake: When Elmer starts hypnotising the bear, the book he was reading is beside him. Later on, it disappears.
Continuity mistake: When we see Elmer reading his book at the beginning of the cartoon, the strap of his gun switches shoulders between shots.