If you were to open up a baby's head — and I am not for a moment suggesting that you should — you would find nothing but an enormous drool gland.

Barry’s line is a piece of comic hyperbole about infancy: the baby is imagined as a creature governed less by thought than by bodily functions—especially drooling. The parenthetical disclaimer (“I am not for a moment suggesting that you should”) mimics the tone of a mock-scientific lecture while also acknowledging the grotesque absurdity of the image, which is what makes it funny. Beneath the joke is a familiar parental observation: newborns can seem like pure appetite and reflex, and adults project meaning onto behavior that is, at first, largely nonverbal and physiological. The humor deflates sentimental idealizations of babies without denying their appeal.