MS of binocular microscope at Connaught Laboratory in Toronto, white-coated man approching, sitting down and peering into microscope. MS of mouse in wire cage. Interior shots of empty chemical laboratory in University of Toronto's Walberg Building, pupils coming in, working at tables. Rear HAS of students in class in the new mechanical building at University of Toronto. Students arriving past camera, taking their seats, professor visible in the distance at front of class. MLS of professor speaking (silent), heads of students in foreground. MS of slide projector operator in booth as seen through glass, operator putting out light prior to slide show. Shots of group of doctors examining man's neck. MCS of interns wheeling patient to operating room. ECU of tumor on man's neck, of finger tips of doctor moving into frame. Shots of boy looking at rat in wire cage. Shots of several white mice in cage. HAS of test tube being emptied into beaker. MS of girl working at keypunch machine. CU of cards in automatic sorter.