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



The view taken by the last named observers seems, like Graham Kerr's, 

 to be somewhat of the nature of a compromise. 



They point out that all authors are agreed as to the activity and 

 multiplication of the neurilemmal cells in the peripheral segment of a cut 

 nerve, and that these unite together into long strands, but if the central 

 end is compared with the peripheral the activity in the former is much 

 greater and the formation of nerve-fibres is there rapid ; these grow in length, 

 assume a contorted course, become myelinated, and an axis cylinder is well 

 defined. In the peripheral end the process is much slower, excitability 

 never returns if union with the central end is prevented, and no real 

 differentiation of axis and sheaths takes place. If the ends are united, 

 then restoration of the peripheral end is more rapid. 



They point out that this is due to the fibres at the central end remaining 

 in communication with their cells of origin and so are under their influence. 

 The cutting of the nerve has suppressed in the peripheral end all func- 

 tional acts, and in consequence all nutritive acts depending on the nervous 

 centres cease also. In the central end, on the other hand, the internal work 

 elaborated by the cells still reacts on the fibres and favours their nutrition 

 and growth. 



By the help of Cajal's silver method they describe and figure rows of 

 granules formed in the peripheral segment, especially in the neighbourhood 

 of the neurilemmal nuclei and independently of central union, and believe 

 that these unite to form neuro-fibrillae which, however, do not become 

 functional until activated by union with the central fibres.* Cajal, how- 

 ever, criticises this part of their observations and conclusions, and does not 

 believe that the striations described are real neuro-fibrils. 



In a sense, therefore, they believe in autogenetic regeneration; in fact 

 they regard it as the only form of regeneration, and that the difference 

 between what is seen at the central and peripheral ends is one of degree 

 only, being more active and efficient at the former situation. 



They, however, part company from Bethe, for they regard the functional 

 activity of the central nervous system as being absolutely indispensable for 

 the return of function in the nerve-fibres and also for their complete 

 histological restoration. They consider that the nerve cell and its axis 

 cylinder constitute a functional unit, and regard the mere fact that the 

 latter undergoes degeneration when cut off from its cell of origin as 

 sufficient evidence of that. 



Perhaps the most steadfast upholders of the theory that peripheral nerves 



* Similar appearances were also described by Biingner, ' Ziegler's Beitrage,' vol. 10, 

 p. 321 (1891). 



