[Evaluation of amputation techniques for the study of limb regeneration in the newt and toad]

A comparison between forelimb amputations through the radius-ulna and the humerus was made in the adult newt, Cynops pyrrhogaster pyrrhogaster and the young toad, Xenopus laevis. Newts regenerated their forelimbs after the amputations and the new parts resembled the old in structure and function. Toads regenerated their forelimbs incompletely after the amputations. The new parts lacked joints and fingers showing a simply elongate pattern. The effect of re-amputation of exposed bone on the regeneration was evaluated in the adult newt. A left forelimb was amputated through the humerus and the exposed bone which protruded from the cut surface due to the relationships of the soft tissues, was then re-amputated a few minutes later. A right forelimb of the same individual was simply amputated without re-amputation of the exposed bone. Newts regenerated both forelimbs simultaneously. The new parts resembled the old in structure and function.