Max and the Flirtometer (Le Baromètre de la Fidélité)
The Linders are given a long tube filled with clear liquid and told that their fidelity is proven as long as the liquid stays clear (no swabs or body fluid samples required!). It is missing the opening scene, as described at the Film: Ab Initio blog, which notes “Its brand of humour makes it a forerunner for the screwball comedies of the thirties and forties”. Features the Max Slide.