The Happy Microbes (1909)

Original title: Les Joyeux microbes

A scientist has acquired a microscope and is showing it off to his friend. He takes various body samples - hair, phlegm, etc. - and puts them under the microscope. The "microbes" coalesce and form different shapes, creating caricatures of various people, such as mothers-in-law and drunks. These animated characters goof around in traditional cartoon fashion.