“The Germans Burn Their Dead in the Blast Furnaces.” Le Petit Journal, April 16, 1916.
This might be a reference to one of the more bizarre propaganda stories of the First World War - Kadaververwertungsanstalt, “Corpse-Rendering Factories”. Fats being scarce in the Central Powers due to a British naval blockade, it was rumored the Germans were operating factories behind the front lines to burn their war dead down for the fat to make candles, nitroglycerine, etc. The source was a German newspaper story, wherein the Allies (perhaps deliberately) mistranslated the German word Kadaver - which refers to non-human corpses in all cases except medical dissection.
The accusations were false, though they naturally enjoyed some popularity in the Allied countries. Nevertheless, the Nazi regime which was to take power in Germany several years later would turn a similar idea against its civillian population.