1906.] 



Regeneration of Nerves. 



265 



All the medullated nerve-fibres found in the peripheral end of a cut nerve, 

 which had been sutured to the central end, degenerated when the central 

 end was again cut nearer the spinal cord ; in other words, all the nerve-fibres 

 were fibres which were connected with the central nervous system. If the 

 regeneration had been autogenetic, this would mean that every one of 

 them had become united with the end of a nerve-fibre in the central 

 stump ; on the autogenetic theory this is highly unlikely, whereas it is quite 

 simply accounted for on Wallerian lines. If the number of medullated 

 fibres in the peripheral end was small, then the connection with the central 

 end was found to be slight. If no connection occurred, then medullated 

 nerve-fibres were entirely absent. Bethe admits a variability in the number 

 of medullated fibres, and this again, though easily explicable on the view that 

 such fibres come from the central end, is not accounted for at all by the 

 autogenetic theory. 



Langley and Anderson further point out that Bethe admits age to be an 

 important factor in the case ; in adult animals he has little or no proof of 

 autogenetic regeneration. This is a very weak point, for surely the difference 

 is due to the greater ease with which reunion with central nerves occurs in 

 young and growing animals. 



Lugano* objects to Bethe's views on much the same lines as Langley 

 and Anderson. 



Cajal,f from the histological point of view, has made a very complete 

 rejoinder to Bethe's work. He has also controlled his results by noting the 

 effects of stimulating the nerves. We are unfortunately not able to read 

 the full account of his work in the original Spanish, but the numerous 

 illustrations he gives remind us very forcibly of what we have seen in our 

 own microscopical work. We have, therefore, to rely on the brief summary 

 he has published in French. By the help of his new silver method he comes 

 to the conclusion that the new formation of nerve-fibres in the peripheral 

 stump is exclusively due to growth from the central end. He describes the 

 long and often contorted course of these growing fibres in the swelling at 

 the cut central end, and shows that they ultimately reach their goal, the 

 peripheral stump, in time and in spite of all hindrances. The greater the 

 obstacles interposed, the later does the union and consequent regeneration 

 in the peripheral end occur. He also calls attention to the olive-shaped 

 swelling at the free end of each growing axis cylinder. These are also 

 figured by Marinesco and Minea.J 



* 1 Riv. di Patologia nervosa e mentale,' November, 1904, p. 550. 

 t Loc. cit. 



\ " La loi de "Waller, et la legenerescence autogene," by M. G. Marinesco and J. Minea, 

 ' Revista Stiintelor Medieale,' No. 5, September, 1905, Bucharest. 



