 Complete the following phrase:  Among the first films to be sold with text brochures to aid teachers were nature documentaries focusing on the time-lapse photography of plants and close-up footage of animals. These were credited to George Clyde Fisher of the American Museum of Natural History, borrowing much footage from earlier British Instructional Films. Other early films of importance included a Yale University backed Arnold Gesell covering early child development and a slow motion study of football techniques with popular coaches like Biff Jones of West Point and H.E. Von Kersburg of Harvard. Dr. Carey Croneis supervised some geology subjects and also worked on the science pavilion at the 