Short piece showing the safe method of using diseased potatoes as a substitute for flour in Britain, 1918.
The action is shown on a workbench. First the diseased pieces are cut out and discarded, and the potatoes sliced. Then flowers of sulphur are heated into a gas, which is captured in a jar. The slices of potato are put in the jar to bleach them, then taken out and put in an oven to dry. Finally they are passed three times through a mincer and emerge as flour.