THE URINARY TRACT. 



775 



and has nothing in common with tubercle, except that, the watery portions 

 having been absorbed, the pus-corpuscles shrivel and become partly trans- 

 formed into fat-granules. In the caseous and fatty degenerations of tubercle 

 we observe an analogous result, the cause of these processes being identical 

 i. e., the absence of blood-vessels. 



Formation of Cysts. Pathologists hold widely differing views regarding the 

 origin of cysts. Some claim that cysts arise from the distended capsules, 

 entirely overlooking the fact that cysts are not infrequently found at the 

 periphery of the kidney, where there are no tufts. Others believe that cysts 

 sta,rt in an expanded tubule, without attempting to explain the process by 

 which the tubule attains the size of a cyst. 



I have frequently observed tufts which were considerably reduced in size, 

 while the space between them and the wall of the capsule was filled with a 

 finely granular mass, evidently sero-albuminous in nature. The capsule was 

 in no instance markedly distended, its diameter not noticeably exceeding that 

 of the normal capsular space. Probably such a condition arose from a chok- 

 ing of the uriniferous tubule, followed by a damming back into the capsule of 



FIG. 352. COMPRESSED TUFT IN A CAPSULE, FILLED WITH SERO- 

 ALBUMINOUS LIQUID. CIRRHOTIC KIDNEY. 



T, compressed tuft ; E, detached epithelia of the tuft ; A, linely granular, sero-albuminous 

 liquid ; C, capsule of tuft, unchanged ; O, interstitial, slightly oedematous connective tissue. 

 Magnified 500 diameters. 



the liquid excreted by the tuft. In consequence of the pressure of the accu- 

 mulated liquid the tuft was compressed more and more, until finally its func- 

 tion was abolished. I doubt if we have any good reason for terming such 

 formations cysts. (See Fig. 352.) 



A more satisfactory explanation of the production of cysts is the follow- 

 ing : The first thing noticed is an abundant formation of inflammatory cor- 

 puscles in circumscribed districts of the kidney-tissue. These maybe situated 

 in the cortex or in the pyramidal substance: Many of these corpuscles evi- 



