OPEEATIONS ON THE FOOT 105 



tissue elements permeated by nerve fibres which have 

 grown out from the axis- cy Under s of the nerve stump. 

 It may vary in size from a pea to a hazel-nut, and is 

 frequently the cause of much pain. This must be cut down 

 upon and cleanly removed, taking away at the same time 

 as much of the nerve as is possible. 



Reunion of the Divided Nerve. — We may say at once that 

 ' reunion ' in the popular sense of the word does not take 

 place. At a varying period after section, however, we do 

 get a return of sensation. This is brought about in the 

 following manner : The axis-cylinder of the nerve, still in 

 connection with the spinal cord, swells somewhat, and 

 hypertrophies. The cells of this hypertrophied portion 

 show a great tendency to proliferate and produce new nerve 

 structure. This growing point splits, and gives rise to 

 several fibrils, which are new axis-cylinders. These com- 

 mence to grow towards the periphery, and, in so doing, 

 grow through the cicatricial tissue that has formed at the 

 seat of the operation. 



After passing through the cicatricial tissue (the amount 

 of which tissue, of course, controls the length of time that 

 insensibility remains), the growing axis-cylinders reach the 

 degenerated portions of the nerve below the point of section. 

 It is along the track of the old nerve that the new growths 

 from the stump reproduce themselves. 



The fact of the new growths having to pass through the 

 fibrous tissue of the cicatrix before they can gain the course 

 of the old nerve, along which latter their progress of growth 

 is comparatively easy, affords ample illustration that as 

 large a portion as is possible of the nerve should be removed 

 when operating, in order to convey insensibility for the 

 longest time. After reunion, of course, nothing remains 

 but to repeat the operation. 



Tlie Existence of an Adventitious Nerve-supply. — While 

 not exactly a sequel of the operation, the fact that it is not 

 discovered until after the operation has been performed 

 warrants us in mentioning it here. It is not an uncommon 

 thing in the lower operation to find that sensation and 



