No. 647] AUTOPHORIC TRANSPLANTATION 555 



centripetally from the retina towards the thalamus op- 

 ticus. In regeneration this same process need only be 

 repeated. Edward Uhlenhuth, while working at our 

 " Biologische Versuchsanstalt, " proved in 1912 that the 

 optic nerve of salamander eyes implanted on the back 

 of the same species grows centripetally towards the spinal 

 cord and even in several instances united with the next 

 spinal ganglion. These transplanted eyes were of course 

 devoid of function, as the nerve had not reached its 

 proper center, but it was of greatest interest to note that 

 the eye, although severed and removed from its natural 

 connection, had totally regenerated after a short period 

 of partial degeneration. Bearing these two points in 

 view, the centripetal growth in ontogeny and the same 

 process in transplanted eyes, we see our theoretical de- 

 mands for the reattachment of replanted eyes fulfilled : 

 the nerve fibers will grow backwards through the orbit, 

 continuing on their usual path and probably finding good 

 conditions there in the degenerating central stump. The 

 usual assumption that function of a sensitive organ can 

 not be restored after severing the nerve is based on false 

 presumptions, especially the idea that the proper central 

 nerve center is responsible for regeneration. We have 

 in several instances proved that it is not necessary for a 

 body part to be connected with its normal nervous center 

 for regeneration to set in and proceed till completion. I 

 may call attention to Oskar Kurz's transplantations of 

 knees taken from developed tritons and placed on the 

 side of the same animal. Out of this bit of leg all distal 

 parts were regenerated, tibia, fibula, foot and toes, al- 

 though connection of the nerve-stump remaining in the 

 graft with the normal nervous center in the lumbar region 

 can not have taken place. It is quite another question, 

 how far the presence of nerve is necessary for restoration 

 of normal form; a question often confounded with the 

 inability of reestablishing function after sovering of 

 nerves. I will not enter into these problems here, as they 

 are being investigated by several of my fellow-workers 



