158 DISEASES OF THE HOESE. 



surfaces. The color of calculi varies from white to yellow and deep 

 brown, the shades depending mainly on the amount of the coloriiig 

 matter of blood, bile, or urine which they may contain. 



Renal calculi. — These may consist of minute, almost microscopic, 

 deposits in the uriniferous tubes in the substance of the kidney, but 

 more commonly they are large masses and lodged in the pelvis. The 

 larger calculi, sometimes weighing 12 to 24 ounces, are m.olded in the 

 pelvis of the kidney into a cylindroid mass, with irregular rounded 

 swellings at intervals. Some have a deep brown, rough, crystalline 

 surface of oxalate of lime, while others have a smooth, pearly white 

 aspect from carbonate of lime. A smaller calculus, which has been 

 called coralline, is also cylindroid, with a number of brown, rough, 

 crystalline oxalate of lime branches and whitish depressions of car- 

 bonate. These vary in size from 15 grains to nearly 2 ounces. Less 

 frequently are found masses of very hard, brownish white, rounded, 

 pealike calculi. These are smoother, but on the surface crystals of 

 oxalate of lime may be detected with a lens. Some renal calculi are 

 formed of more distinct layers, more loosely adherent to one another, 

 and contain an excess of mucus, but no oxalate of lime. Finally, a 

 loose aggregation of small masses, forming a very friable calculus, 

 is found of all sizes within the limits of the pelvis of the kidney. 

 These, too, are in the main carbonate of lime( 84 to 88 per cent) and 

 without oxalate. 



Symptoms of renal calculi are violent, colicky, pains, appearing sud- 

 denly, very often in connection with exhausting work or the drawing 

 cf specially heavy loads, and in certain cases disappearing with equal 

 suddenness. The nature of the colic becomes more manifest if it is 

 associated with stiffness of the back and hind limbs, frequent passage 

 of urine, and, above all, the passage of gravel with the urine, espe- 

 cially at the time of the access of relief. The passage of blood and 

 pus in the urine is equally significant. If the irritation of the kid- 

 ney goes on to active inflammation, then the symptoms of nephritis 

 are added. 



Ureteric caZcvli. — These are so called because they are found in the 

 passage leading from the kidney to the bladder. They are simply 

 small, renal calculi which have escaped from the pelvis of the kidney 

 and have become arrested in the ureter. They give rise to symptoms 

 almost identical with those of renal calculi, with this difference, that 

 the colicky pains, caused by the obstruction of the ureter by the 

 impacted calculus, are more violent, and if the calculus passes on 

 into the bladder the relief is instantaneous and complete. If the 

 ureter is completely blocked for a length of time, the retained urine 

 may give rise to destructive inflammation in the kidney, which may 

 end in the entire absorption of that organ, leaving only a fibrous 



