Parent and daughter axon density in the limb stump and regenerating limb bud of the newt.

Axonal density in the amputated limb stump and regenerating limb bud of the newt was determined by axon counts and planimetry of silver-stained sections at various distances from the amputation level. Traumatic degeneration occurred for at least 250 micron proximal to the amputation level. Axonal density at 250 micron distal to the amputation was less than half that at 100 micron. Attempts to increase in situ axonal density in limbs of animals naturally incapable of limb regeneration can be based on specific knowledge of natural traumatic degeneration and sprouting prior to axonal manipulation.