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. 25. Above is shown the relation between a cell-body such as is 

 found in a dorsal root ganglion and the associated afferent fiber. The 

 arrow suggests the course of passing impulses. Whether these actually 

 visit the cell-body has been much discussed. The problem recalls the 

 situation represented below: the traveller from Washington (W.) to New 

 York (N. Y.) may be carried into the Broad Street Station in Philadel- 

 phia (P.) or he may be taken past the junction point without making the 

 detour. 



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 

 the gray matter. The manner of their ending is some- 

 what in doubt but in all probability they lead to 

 the dendrites of various cells. Impulses led into the 

 nervous system by afferent fibers can thus be carried 

 to the receiving processes of those nerve cells which 



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