NEUROMA 151 



yielding primitive sheath, an imperfect provision of the 

 nodes of Ranvier, or a perhaps too fluid condition of the 

 white substance of Schwann, either or all of which may 

 suffice, along with an exciting cause, to initiate and con- 

 tinue the neuromatous growth by allowing passive 

 accumulation of that substance within the peri-neurium of 

 the implicated nerve trunks, in obedience to the influences 

 of local anatomical conditions and histological environ- 

 ment. Thus, for instance, is determined that the long 

 diameter of the tumour is universally parallel with the 

 direction of the affected nerve, which circumstance is due 

 to the escape and deposition of the tumour material along 

 the lines of least resistance. 



Neuroma is, therefore, not a "new growth" in the 

 strict acceptation of the phrase, but an accumulation of 

 the material being locally circulated through the interstices 

 of the neural tubules in certain definite areas, where the 

 operation of local conditions secures its conversion into 

 definite nodules and larger masses. Generally speaking, 

 these neuromatous nodules and masses may be regarded 

 as due to stasis of the medullary circulation and substance 

 alone, inasmuch as the axis cylinders of the involved nerve 

 fibrils remain intact, and capable of transmitting nerve 

 impulses ; therefore, we have here to deal with, in the 

 main, an arrest of medullary circulation and subsequent 

 accumulation of that substance within the neurilemmar 

 coverings of the affected nerve trunks, and, consequently, 

 with the insulating media and the transmission phenomena 

 of innervation, as they in turn become affected by these 

 altered environing circumstances. 



