In the Center Ring -- Description du film [en anglais] :
« Of all the daredevil circus performers in this animated short, it is the two children in the center ring who are the most courageous.The film is one of a trio of animated shorts by Lynn Smith that form an anti-smoking campaign, produced by the National Film Board of Canada, with the participation of Health and Welfare Canada. Although this particular campaign was originally aimed at children, the three films have been shown on TV nationwide. »
-- National Film Board of Canada

Source :
National Film Board of Canada. "NFB -- In the Center Ring" National Film Board of Canada. http://onf-nfb.gc.ca/en/our-collection/?idfilm=50828.