276 Drs. Mott and Halliburton and Mr. Edmunds. [June 12, 



impression that they had never been previously performed. But on looking 

 up the literature we find this is not the case. Like so much of the present 

 work set going by the revival of the autogenetic theory, this experiment has 

 also been performed by others. As long ago as 1859 Philippeaux and 

 Vulpian did it, and obtained the same result as we have ; we can hardly 

 doubt that this formed one of the factors that later led Vulpian to abandon 

 the autogenetic theory. 



Fig. 5. — Wallerian degeneration of regenerated nerve-fibres. Cat. Drawn from a 

 teased preparation with the camera lucida. Marchi method of staining. Magnified 

 820 diameters. 



Bethe also has repeated the experiment ; he states that a nerve which has 

 regenerated autogenetically degenerates afresh when it is again cut; that 

 this degeneration occurs only in the peripheral segment, and that the central 

 end remains intact. According to him this experiment convinces him in 

 a striking way that the integrity of the central end does not depend on its 

 connection with the cells in the central nervous system. This is an 

 excellent example of arguing in a circle, for his first assumption that 

 autogenetic regeneration has occurred is entirely unwarranted. 



v 



