I watched this film on a DVD that was rammed with short films from the period. I didn't watch all of them as the main problem with these type of things that their value is more in their historical novelty value rather than entertainment. So to watch them you do need to be put in the correct context so that you can keep this in mind and not watch it with modern eyes. With the Primitives & Pioneers DVD collection though you get nothing to help you out, literally the films are played one after the other (the main menu option is "play all") for several hours. With this it is hard to understand their relevance and as an educational tool it falls down as it leaves the viewer to fend for themselves, which I'm sure is fine for some viewers but certainly not the majority. What it means is that the DVD saves you searching the web for the films individually by putting them all in one place but that's about it.
A man sees he is being filmed and starts to remonstrate with the camera crew about it. Finally losing his temper the man closes in the camera and, well, eats it. This sounds simple and it is but I had assumed that the film would merely end on the darkness of the man's mouth as the punchline. Instead the delivery is cleverer than that and we step back to see the camera and the cameraman falling into the "mouth" before we then cut back to the man walking backwards chewing. It is a clever combination of camera shots to create the gag and invention work from Williams. Not brilliant but quite clever when you look at it in context.