ANIMAL [AND VEGETABLE 198 



become at once apparent, for they would afford protection 

 to the axon against extensive degeneration consequent 

 upon injury. 



Let us examine a node in a piece of bamboo. 

 According to Strasburger there is a 

 wax incrustation, in the form of small 

 rods, at a, b. The interior of the stem, 

 between the nodes, is filled with a soft 

 sponge-like substance which, while the 

 plant is alive, transmits electricity each 

 internode indeed seems to bear some 

 resemblance to a cell so that the line 

 a, b, notwithstanding the wax incrusta- 

 tion, does not involve a break of Fig 103 

 continuity. That being so, it would 

 appear that the node is of the nature of a synapse, 

 and that if the current is not inductively transmitted 

 there is considerable added resistance at each node. 



These nodes, be it remarked, occur at regular intervals 

 upon the stems of bamboo (all canes) and sugar-cane, in 

 much the same way as they do along the course of human 

 nerves. 



In the nodes of Ranvier the line a, b is absent, and it 

 does not necessarily follow because a colouring matter like 

 picro-carmine diffuses into the fibre only at the nodes, and 

 stains the axis-cylinder red, while it does not diffuse 

 through the white substance of Schwann, that there is any 

 difference in the substance of the axon itself at those 

 points. 



But that there is a phase in the nature of a com- 

 paratively high resistance across the line a, b is, I think, 

 more than probable ; for this reason : 



When a nerve is severed, degeneration in the proximal 

 segment takes place only as far as the first node of Ranvier. 



Consider what, from an electrical point of view, that 



o 



