REGENERATION 



449 



Fig. 24. — Technique for local exposure of tadpoles, Pdobates fuscus. a, external view 

 of one of the holders shown in c with lead cover in place as during exposure; h, method of 

 fastening the tadpoles under the lead shield by means of a bent strip of lead and wooden 

 block; c, arrangement of such holders in a crystallization dish during irradiation. {From 

 Scheremetjcwa and Brunst, 52.) 



o\ 



d 



Fig. 25. — Effects of X-rays upon regeneration of tail in tadpole of Pdobates fuscus. 

 a, b, and c, three regenerates at 32 days after local exposures of 1500 r and amputations 

 immediately following; d, normal regeneration of control. {From Scheremetjcwa and 

 Brunst, 52.) 



Fig. 26. — Schematic representation of dififerent reactions in tail regeneration of tadpoles 

 of Pelobates fusc^^s following X-ray exposures ranging from 1500 to 2250 r. Chr, regenerated 

 chorda; Chst, stump of chorda; G, border between the new and old tissue; Rmr, regenerated 

 spinal cord. {From Scheremetjewa and Brunst, 52.) 



