NBPHEITIS. 425 



occurs as renal colic ; in others it is referred to the spine and 

 termed " rachialgia ; " sometimes it is reflected along the nerves 

 of the corresponding abdominal segments, producing modifica- 

 tions of tactile sense, and in others it radiates down the outer 

 side of the thigh, or appears in the knee, the heel, or the sole of 

 the foot. The pains are in part due to a stretching of the renal 

 plexus, which is an offset of the solar plexus and accompanies 

 the renal vessels. The nerve supply of the kidney is derived 

 from the tenth, eleventh and twelfth dorsal and first lumbar 

 segments of the cord, through the splanchnic nerves. Kenal 

 pain may be referred along any of the sensory nerves derived 

 from these segments. In some instances, the displaced kidney 

 exercises direct pressure on branches of the lumbar plexus, 

 i.e., on the ilio-hypogastric, ilio-inguinal, genito-crural, external 

 cutaneous or anterior crural nerves. 



Nephritis. Infective or toxic matter may reach the kidney by 

 the blood stream, the ureter, or the lymphatics. Blood infection 

 is probably the cause of most cases of nephritis. The toxic 

 material may have been ingested or be the product of the activity 

 of bacteria in some other part of the system. The cortex of the 

 kidney contains the active secretory epithelium, and the blood is 

 chiefly distributed to this part. Consequently the stress of 

 inflammation falls chiefly on the cortex, involving the glomeruli 

 and the convoluted tubes. The blood supply of the convoluted 

 tubes is derived from the afferent vessels of the glomerular tufts. 



The tough renal capsule resists the swelling of an acutely 

 inflamed kidney, and thus may. produce further damage. The 

 favourable results of nephrotomy in acute nephritis may be 

 attributed to diminution of renal tension. The tension may 

 induce acute renal colic simulating that produced by calculus. 

 The practice of wet cupping the loin in acute nephritis is justified 

 by the free connexion which exists between the superficial vessels 

 of the kidney, the subperitoneal vascular plexus of Turner and 

 the lumbar vessels. 



Infection which ascends the ureter usually gives rise to a 

 pyelitis before nephritis supervenes, and cystitis may precede 



