678 NERVES OF THE KIDNEY. [BOOK n. 



medullated fibres ; others pass on to the renal plexus without 

 being so connected. 



Nothing very definite is known of the termination of the renal 

 nerves within the kidney. Some of them, and considering how 

 vascular is the kidney, probably a large number, end in the blood 

 vessels ; but some of them must have other endings. We may 

 suppose, but have as yet no clear evidence, that some of them 

 are connected with the epithelium of the tubules. Since under 

 abnormal circumstances afferent impulses sufficient to give rise to 

 very great pain may pass up to the central nervous system from 

 the kidney, at least from the pelvis of the kidney, some of the 

 fibres of the renal nerves are afferent fibres ; and some of the 

 medullated fibres are probably of this nature. 



