Sure, the "Doctor" explaining the circulatory system to children is puffing on a butt, but of all the educational films I watched in school, this is one of the few that I vividly recall. I saw this in 5th grade (public school, c.1987 - long past the film's prime, and even then the teacher gave us a verbal disclaimer about the cigarette), but I still remember the powerful visuals, and any time I've thought about the circulatory system in the decades since, I've recalled "Hemo." I'm sure there are more up-to-date and accurate educational films on this subject available today, but I doubt that any are this entertaining and memorable. Presented with appropriate guidance and context, this remains a powerful educational tool.