The title and plot are a bit of a spoof on the oft borrowed theme of Dr. Jekyll and Mr. Hyde.
The junior chemistry kits popular at the time contained actual chemical ingredients and could be hazardous. Modern versions are much less toxic, but still lots of fun for budding science aficionados.
Among the food items in the modern kitchen fridge are celery, milk, spare ribs, and a very 60's looking parfait style chilled dessert.
Jerry borrows a very Bugs Bunny signature move when he kisses Tom after being caught.
Not only do both characters break the fourth wall, they make sounds (but don't speak).