LITERARY NOTICES. 



Degeneration of Peripheral Nerves. i 



In 1795 Cruikshank divided the vagus-sympathetic nerve trunk in 

 the neck of a dog and found that, when the section was performed on 

 both sides, death followed very promptly, while a unilateral section was 

 not fatal. He then divided the nerve on one side and, after an interval 

 of three or more weeks, cut the other. The animal survived, thus show- 

 ing that the severed trunk had meanwhile united. This experiment 

 seems to have been the starting point for a long series of research upon 

 the nature of the dependence of nerve fibres upon nerve centres, which 

 have culminated in the masterly monograph before us. 



Flourens (as it is claimed) succeeded in suturing the cut ends of the 

 median and ulnar nerve, each to the stump of the other. Functional 

 union was effected and stimulation of the dorsal nerve caused motion of 

 the ventral peripheral muscles and vice versa. Since Flourens' time the 

 fact that a severed nerve may again become functional has been repeat- 

 edly demonstrated, but it has not been so easy to determine whether the 

 union was preceeded by a degeneration and regeneration of the entire 

 peripheral portion. The histological problems involved, c. g. whether 

 the axis cylinder repenetrated the sheath from the stump, have remained 

 unsolved. 



When the nerve is cut and the stumps not reunited or sutured, every 

 one admits that a process of degeneration follows. Beyond this there is 

 little unanimity. All admit that the myelin disappears, but Neumann, 

 Eichhorst, Mayer, etc., suppose that the myelin simply suffers transfor- 

 mation and forms the material of the new sheath in case of regeneration. 

 While some describe the process of degeneration as beginning at the 

 proximal end, the majority recognize the process as coetaneous through- 



1. Howell, W. H. and Huhek, (i. C. .V Physioldgital, Histologieiil and flinical 

 Study of the Degeneration and Regeneration in Peripheral Nerve Fibres atter sever- 

 ance of their connections with the nevve iciifrcs. .Tournal of Physiology. XIII. o. 

 IS'.Ci. 



