 That clip was from the Friz Freleng short "Clean Pastures".Panning left over the cheering crowd, the camera reveals a singing Heidi on the cover of her eponymous book, a literal "Thin Man" when viewed from the side (a caricature of William Powell as Nick Charles) walking into the "White House Cook Book" and, when walking back out and seen from the side, shows that he has packed on some weight in his posterior.Whistler's Mother, on the cover of the book, "Great Works of Art" whistles "Ain't She Sweet", then three "Little Women" (three Jane Withers clones) and three "Little Men" (three Freddie Bartholomew clones) sing with Old King Cole (spoofing deep-voiced Warners character actor Eugene Pallette), the characters of "The House of the Seven Gables" (seven identical caricatures of Clark Gable), and a drumming bulldog intended to parody "Bulldog Drummond".