A cohort of human red cells of the same age persists in the circulation for about 110 days without access to repair but disappears over the next 10 days. Hyperosmotic stress accelerates the process exponentially. The kinetics are Avrami in all cases we have examined, withn=2. We have previously modelled this as a stress failure in a viscoelastic cytoskeleton, but because of the two dimensional long range order in the cytoskeleton, the data can also be interpreted as a state change in a crystalline material.