Panel 1: We start off with MikeClone asking RetJohn if he had a dog as a boy. The answer is "Yes"; his name was "Wimpy". "Wimpy?", the budding genius asks?
Panel 2: RetJohn reminds his son of the hamburger-eating moocher from "Thimble Theater staring Popeye". Apparently living in a time and place wherein they run the cartoons from the forties, MikeClone mutters "Yeah" because he'd gladly pay you Tuesday for a puppy-dog today.
Panel 3: He then asks the question I want to ask: why RevElly is so dead-set against having a dog. RetJohn's answer is that she's being practical. She'd be the one looking after the dog, after all.
Panel 4: It only stands to reason that, with her at home alone while he's sucking at being a dentist, she'd want to minimize her workload. The kid murmurs acceptance of his father's argument.
Panel 5: He then thought-bubbles that he now knows that he's too young for a dog and can't stand it.
Summary: It's a good thing Old Lady Baird is going to be better at tugging at RevElly's heartstrings, isn't it? Once she appeals to the younger woman's sense of fair play, we'll have lots of fun seeing that she's a lousy pet owner.