Well, we'll never know what Horton was going to say to Mayzie. Because at that very moment "[t]here rang out the noisiest ear-splitting squeaks" (186). That's right—it's coming from the egg.
Horton has been sitting on the egg for fifty-one weeks. Just shy of a year!
Beyond excited, Horton says, "My egg!/ My EGG! WHY, IT'S HATCHING!" (188-189) The "My" is indicative of a strong attachment on Horton's part, wouldn't you say?
This scene is gorgeously and hilariously illustrated. The force of the hatching egg lifts Horton's hind quarters into the air and he has to balance on the tree with his front feet to keep from falling. We highly recommend you check it out.