THE UEINAKY ORGANS. 



643 



RENAL CALCULI. 



In the kidneys of new -born children, from the first to the fourteenth 

 day after birth, the large tubes of the pyramids often contain small, 

 brownish, rounded bodies composed of the urates of ammonium and so- 

 dium. Similar masses may also be present in the calyces and pelves. 

 In still-born children these masses are usually absent. The carbonate 

 and phosphate of lime may be deposited in the tubes of the pyramids, in 

 the form of white linear masses, in the kidneys of old persons and of 

 those who have suffered from destructive diseases of the bones. 



Urate of soda in the form of acicular crystals is deposited both in the 

 tubes and stronia of the kidneys of gouty persons. 



Concretions of the urinary salts are often formed in the pelves of the 

 kidneys. They may remain there as rounded masses, or they may attain 

 a large size and be moulded into the shape of the pelvis and calyces. 

 Smaller calculi may pass into the ureter and either become impacted 

 there or pass through it into the bladder. The most common form of 

 calculus is that composed of uric acid. But they may also be formed of 

 uric acid with a shell of oxalate of 

 lime, or of oxalate of lime alone, or 

 of the phosphates, or of cystin. 



The most serious result of the 

 presence of these calculi is the oc- 

 clusion of the ureters or the incite- 

 ment of pyelo-uephritis. 



TUMORS. 



Small fibromata, lipomata, 1 myo- 

 mata, and angiomata may occur in 

 the kidney and with the exception 

 of the fibromata are most common 

 in the cortical portion. Papilloma 

 may form in the mucous membrane 

 of the pelvis. Sarcoma, myxosarcoma, 

 and endothelioma, often of large size, 

 may develop in the kidney. These 

 tumors are frequently soft and vas- 

 cular and are prone to hemorrhage. Primary sarcoma of the kidney is 

 common in children. Secondary sarcoma of the kidney is not rare. 



Adenoma is of frequent occurrence in the kidneys. It usually origi- 

 nates in the cortex and may be invisible to the naked eye (Fig. 404), or, 

 in the form of a well-defined, circumscribed nodule (Figs. 405 and 406), 

 it may invade the medulla or largely replace the kidney. The adeno- 

 mata are usually light in color save when very vascular with hsemor- 



1 See for studies and bibliography of lipoma Ulrich, Ziegler's Beitr. z. path. Anat., 

 Bd. xviii., p. 603, 1895; also Miller, Virchow's Arch., Bd. cxlv., p. 339, 1896. 



FIG. 404.- SMALL ADENOMA OF KIDNEY. 

 Situated in the cortex. 



