"Shoveling warm human hearts and bodies into the furnace." 

Hitler knew what he was doing. He replicated his experience of the First World War with Jews substituting for German soldiers.

Harry Pearson, reported by Winifred Holtby "Pearson told me about all the enormities he had seen at the front: the driving--the callous, perpetual driving by some great force which shoveled warm human hearts and bodies, warm human hopes, by the million into the furnace.”