"Ferdinand" has the same lush art direction and is based on the same kind of sweet parable as a Silly Symphony, and was released while that series was still going (it would end on a high note with "The Ugly Duckling" in 1939), but it's something else altogether: the first of Disney's "storybook" cartoons. It is, in fact, based on a children's storybook, but that's not the point. The point is that there is spoken narration, and the drawings ILLUSTRATE the narration, much as they would illustrate the printed text in a picture book.
So far as I know this is the first cartoon from ANY studio to attempt this kind of thing. It's not the best; narration and illustration are too independent of one another. I'm not saying that Disney should have used any of those old cartoon gimmicks - characters arguing with the narrator, etc. - which postmodernists delight in as though they weren't half obvious; such gimmicks would not, in a sincere work such as this, have worked. But words and pictures should partner each other in a subtle dance; each should know when to withdraw and place the narrative burden upon the other. I can't put it more precisely than this; but watch two "storybook" cartoons that Disney produced later - "Lambert the Sheepish Lion" from 1951, "Pigs is Pigs" from 1954 - to see the dance perfected, resulting in an animated storytelling sessions that FLOW, from beginning to end.
To be fair, unqualified successes like these are rare. Most of Disney's later "storybook" cartoons also get it wrong, some of them are dreadful, and not a single one apart from the two I've named can match the charm of the first.