DISEASES OF THE UKINARY SYSTEM. 197 



What is hydronephrosis? 



This condition is also called hydrops renum, and is an accu- 

 mulation of non-purulent fluids, the result of obstruction, causing 

 a dilatation of the pelvis and calices of the kidney, with atrophy 



of its substance. 



What may cause dropsy of the kidney? 



It may be caused by pressure from tumors, calculi, blood-clots, 

 parasites, etc., blocking up the ureters and producing the accumu- 

 lation of fluid in the pelves of the kidneys. This condition is 

 difficult to diagnose. 



Define nephroptosis. 



This is called floating-kidney, and is a condition due to the 

 kidney breaking loose from its position, being normally held by its 

 capsule, by the peritoneum, and by blood-vessels. It is rare and 

 only interesting to us on post mortem. 



What is meant by nephrolithiasis ? 



By this is understood a formation in the kidney or its pelvis 

 by the deposition of certain of the solid constituents of the urine. 



THE URINE. 



What are the physical properties of the urine ? 



It is more or less transparent, of a yellowish color, is alkaline, 

 neutral, or acid in reaction, has a strong and peculiar odor, and a 

 specific gravity varying from 1020 to 1060. 



Describe and give some of the normal constituents of 

 the urine. 



Normal constituents are the result of tissue changes taking 

 place in the body. 



The inorganic constituents are principally sodium, potassium, 

 calcium, and magnesium (carbonates, chlorides, sulphates, etc.). 



The organic constituents are chiefly urea, uric acid, hippuric 

 acid, etc., coloring matters and extractives. 



What changes may take place in disease ? 



Abnormally, there may be an increase in the normal constitu- 

 ents or they may be present abnormal substances. These changes 

 cause alterations in the quantity, color, odor, reaction, specific 

 gravity, etc. 



