The retelling of this Pennsylvania folk tale has its ease and its ends. An ornery but reasonable mule, Old Satan is put out when given a job on a treadmill, because it never gets him anywhere. He fumes and frets until he drinks up a batch of soft soap the farmer's wife made. Soft soap proves gentling. It also makes old a provider of lather for all occasions and the proud owner of a shaving brush tall he bequeaths to future muledom. The author's red and black cartoons look scrubbed.