642 THE URINARY ORGANS. 



Adult may be single aiid occur in otherwise normal organs. There may 

 be one or more cysts filled with clear or browii serum or gelatinous 

 material (Fig. 403). These cysts do not appear to interfere with the 

 function of the kidneys. 



In chronic diffuse nephritis, especially in the atrophic form, groups 



FIG. 403. SINGLE CYST OF THK KIDNEY. 



of tubes may be dilated. Apparently one or more of the larger tubes 

 in the pyramids is obstructed, and this causes dilatation of a correspond- 

 ing group of tubes. Such a dilatation may be moderate in size, or it 

 may form cysts visible to the naked eye. Occasionally both kidneys are 

 very much enlarged and converted into a mass of cysts containing clear 

 or colored serum or gelatinous material. The nature of these cysts is 

 uncertain : they may be congenital. They are sometimes associated with 

 similar cysts in the liver. ' 



Small multiple cysts of the ureter, lined with flattened or cuboidal 

 epithelium, are of occasional occurrence, and may be associated with sim- 

 ilar cysts in the pelvis of the kidney. Such cysts in the ureter may be 

 pedunculated. 2 



1 For a study of cystic kidney with extensive bibliography see Ritchie, Laboratory 

 Reports, Royal College of Physicians, Edinburgh, vol. iv. 



' 2 For a resume of cysts of the ureter with bibliography see Harris, Am. Med. , May 

 3d. 1902. 



