THE REPAIR OF A NERVE 



By W. D. HALLIBURTON, M.D., F.R.S. 



It is not probable that many readers of Science Progress have 

 ever experienced the misfortune of having an important nerve 

 cut across. But those engaged in hospital practice, especially 

 in manufacturing districts where machinery is employed, often 

 see accidents of this nature. The result of such an injury is that 

 the parts of the body which the divided nerve served to link 

 with the central nervous system are destitute of the power to 

 move and to feel. The telegraphic service of the body has been 

 interfered with, and the brain is no longer able to transmit its 

 commands to the motor mechanism, nor to receive communica- 

 tions from that part of the sensory surface which is severed from 

 it by the division of nerve fibres. Many of these cases recover 

 after the lapse of time, and this period can always be shortened 

 if by surgical interference the divided segments of the nerve are 

 sutured together. 



If, on the other hand, the injury occurs in the central nervous 

 system, the effects are more serious. Suppose, for example, 

 the spinal cord is divided or crushed, then the main line of 

 communication is no longer capable of conducting nerve im- 

 pulses up and down, and a large area of the body surface 

 is thrown out of connection with the sensorium. And again, 

 unless the division is a complete one, a certain amount of 

 recovery takes place. But the method of repair is different 

 in this case from what it is in our first example — the division of 

 a nerve. 



In the recovery that occurs to a small extent when important 

 conducting paths are cut across in the central nervous system, 

 restoration is not due to the healing of the injured tracts, nor 

 to the regeneration of the divided threads, which are called 

 nerve-fibres; but to the happy circumstance that the complex 

 labyrinth of conducting paths has so many cross connections 

 that it is possible for impulses to avail themselves of these, 



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