776 



THE UEINAEY TRACT. 



dently originated from tubular epithelia. The second stage is characterized 

 by the swelling of the inflammatory bodies, which afterward become pale, 

 and, by a process of liquefaction or mucoid degeneration, are transformed 

 into a hyaline, apparently structureless, mass. We very frequently find in 

 this mass delicate granular fibers, which resemble those of myxomatous tis- 

 sue. The new formation thus produced may, at the outset, be extremely 

 small and irregularly bounded by unchanged medullary corpuscles. With 

 the growth of the cyst more medullary bodies gradually become liquefied, 

 till at length a cavity is established, containing a sero-albuminous fluid, and 

 bounded by flattened, polyhedral medullary corpuscles, which, in this 

 situation, might be designated endothelia. At the periphery a forma- 

 tion of fibrous basis-substance takes place, with the production of a cap- 



FIG. 353. CYSTIC DEGENERATION OF THE KIDNEY IN CHRONIC 

 CROUPOUS NEPHRITIS. 



/, mass of inflammatory corpuscles; M, strings of a myxomatous connective tissue trav- 

 ersing cystic spaces, which are filled with a sero-albuminons liquid ; C, fibrous connective 

 tissue producing the wall of the cysts. Magnified 600 diameters. 



sule the cyst-wall proper. Cysts, therefore, are the products of secondary 

 changes of medullary bodies which had their origin in kidney epithelia. 

 (See Fig. 353.) 



Fatty Degeneration. In. all forms of chronic nephritis fat may appear in any 

 of the constituent tissues of the kidney; more especially, however, in the 

 epithelia and in the interstitial connective tissue. Fat-granules unquestion- 

 ably originate from particles of living matter, for in the epithelia we are 

 able to recognize their connection by delicate filaments with the bioplasson 

 reticulum. 



