The Sunshine Makers (1935)

Cool animation released in 1935. From IMDb:

Sponsored by Borden's Milk---Elsie the Borden Cow is missing but her trademark sunflower is present---this fable has the Sunshine Gnomes (happiness) doing battle with the Blue Devils of Melancholy ( sadness and misery). The gnomes bottle sunshine (milk) and spray it over the unhappy denizens, thereby converting them to Bluebirds of Happiness.