Expernnents in Transplanting Lnnbs 25 1 



op<;ration. After the fourth day Gemelli was in all cases able to 

 detect nerve filaments which arose from the nerves of the host and 

 extended toward the grafted appendage; in somewhat later stages it 

 was found that these nerves entered the latter and that they in all 

 cases preserved their connection with the nerves of the host. 



When, therefore, we consider that Braus, Gemelli and myself 

 have never found cases in which the nerves of the transplanted 

 limb were not connected with the nerves of the host, and also that 

 Banchi himself claims to have found only a small proportion of 

 cases in which no connection could be traced; and further, when 

 we consider that a ready source of contamination was present, and 

 that small nerves in the embryonic body may easily elude observ- 

 ation, we cannot but conclude that Banchi is in error in the inter- 

 pretation of his material, and that there is as yet no satisfactory 

 proof for the claim that nerves may differentiate in a peripheral 

 part when nervous connection with the center does not exist. 2' In 

 order to prove definitely this important proposition, it is necessary 

 that every possible precaution be taken to prevent the formation 

 of anastomoses. The experiments upon which the present claims 

 in favor of the autogenetic development of nerve fibers are based 

 do not measure up to this standard, and the position of those 

 who are now advocating this view on the strength of these experi- 

 ments, in which sources of contamination were not eliminated, 

 presents a strong resemblance to the position formerly taken by 

 the advocates of abiogenesis, while in fact there is no more evidence 

 for the one than for the other. 



EXPERIMENTS 



The experiments, consistmg of two series, which are to be de- 

 scribed below, were made upon larvae of Rana sylvatica and Bufo 

 lentiginosus. 



In the first series limb buds taken from nerveless or "aneuro- 

 genic" larvae were transplanted to normal individuals. The 

 nerveless specimens were produced, as described previously," by 



2'The question of autoregeneration of fully differentiated nerves is here left out of consideration, 

 the writer reser\-ing his opinion on this matter. 

 ^Harrison '04, p. 201. 



