

Growth of Amputated Parts and Grafts 117 



besides the fin margin, the notochord and the spinal cord 

 take part in this new formation. It is interesting that 

 the tail of a tadpole is capable of such a regenerative 

 new formation not only in the caudal direction but also 

 in the opposite direction." 79 



We say then that these phenomena, which the ampu- 

 tated tail of the tadpole presents, can be cited by the pre- 

 formationists against the epigenesists, as well as by the 

 latter against the former. For the former can object 

 that the progress of the histological differentiation in 

 the fragment of tail cut off from all the rest of the 

 organism would denote the absence of any action of 

 the organism upon the development of this part of the 

 body, and the epigenesists on their side could show that 

 the power of the tail to regenerate even in the direction 

 from the tail toward the head, could not be explained 

 by preformation, even with the aid of reserve idioplasm, 

 for that could effect regeneration only in the direction 

 from the head toward the tail. 



It is the same with Bern's celebrated experiments on 

 the grafting of certain fragments of tadpoles upon one 

 another or upon complete tadpoles, which are opposed 

 to simple epigenesis and at the same time indicate a 

 process of epigenetic nature. 



In the first place they are opposed to epigenesis. For 

 in all grafts of parts of tadpoles upon complete tadpoles, 

 the grafted parts have continued their development regu- 

 larly as if they had remained united to their own 

 organisms. Therefore the rest of this organism has not 

 under normal conditions any influence upon the 

 development of these portions. 



"Born: Uber Verwachsungsversuche mit Amphibienlarven. 

 Leipzig, Engelmann, 1897. P. 3233. 



