Lotte Reiniger's Animated "Doctor Dolittle" Feature (1922)-- The earliest Dolittle adaptation of which I'm aware is actually an important piece in the history of animation. Based on Lofting's first book, it was the second feature-length production by Lotte Reiniger, a German animation pioneer whose work employed a "silhouette cut-out" method (rather than the "painted cel" technique Disney would later use). That is, figures were cut out of black paper and positioned on a background; one frame was shot; the animator re-positioned the figures; another frame was shot; and so on ... This painstaking, stop-motion technique produced a unique and effective result. Reiniger's "Doctor Dolittle" was a product of the silent era, so originally it would have been accompanied only by music (although the version I saw had been re-done for television decades later, and had a narration attached). Unfortunately, the original "Dolittle" score is lost: we know, however, that the composer Paul Hindemith (a friend of the animator) was among the contributors!
More to come...