REFLEXES 



97 



The fiber which we have chosen as a type of its order 

 continues from the ganglion to the dorsal portion of 

 the cord. Within this part of the nervous axis it is 

 said to branch into an ascending and a descending divi- 

 sion. These run in the dorsal columns of the white 



FIG. 23. The upper figure suggests the simplest possible basis for 

 reflex action. An afferent fiber, entering through a dorsal root, comes 

 into relation with the cell-body l^dng rise to a motor fiber. This leaves 

 the cord by way of the ventral root. 



The lower figure shows the branching form of the afferent fiber and 

 the possibility that it may play upon a number of motor cells at differ- 

 ent levels. 



matter. Here we have evident provision for the in- 

 troduction of impulses into the cord and we know the 

 cells of the neuromuscular apparatus are close by. 

 It remains to show how a connection can be established. 

 It has been shown by the histologists that the af- 

 ferent fibers in the cord send branches at intervals into 



