Both Bugs and Elmer are in transitional stages of appearance development here, with Elmer wearing the outfit seen on his earlier version, Egghead. Bugs is shorter and had more salmon pink inner ears. Both would evolve further through the next decades.
"Dr. Kilpatient" is a parody of Dr. Kildare, a popular fictional American medical doctor, originally created in the 1930s by author Frederick Schiller Faust (under the pen name Max Brand).
Bugs emerging from inside the Looney Tunes drum (instead of Porky Pig), munching a carrot and saying, "And dat's de end!" rather than the usual "That's All Folks!" only happened one other time - in 1946's "Baseball Bugs."
Bugs pretending to be Elmer's reflection in the mirror parodies the famous mirror scene from the 1933 Marx Brothers' film, "Duck Soup."
Bugs, not his castmate Porky Pig, delivers the closing lines in his usual confident style.