Abstract: An improved hide processing machine has a hide-treating drum supported for rotation about a central longitudinal axis to retain and tumble hides and treating fluids at a closed end of the drum. The drum includes helical partition means extending across the interior of the drum and spirally along the drum axis from its closed end toward its open end, thereby dividing the drum into at least two longitudinally-extending spiral compartments. The partition means prevents movement of hides from one such compartment to another during rotation of the drum, and includes fluid-transmitting openings for free movement of treating fluid between such compartments. The helical partition means can provide a conveying force for retaining or discharging such hides when the drum is rotated in an appropriate direction.