IS DISEASES OF THE KIDNEY. 



increasing emigration of the white blood-corpuscles. Under favor- 

 able conditions these cells may undergo fatty degeneration, and a 

 complete resolution of the process may ensue ; otherwise they may 

 convert themselves into fibrous tissue, causing permanent thicken- 

 ing with or without shrinkage of the intertubular substance. 



In such a case as this, the process drags on for years ; and we 

 find after death both kidneys shrunken, sometimes even to a third 

 of their normal size, and the capsule thickened and opaque, and 

 firmly adherent to the parenchyma. The surface of the organ is of 

 a dull brownish-red, here and there of a dirty-yellow hue. The 

 atrophy being complete in some parts of the kidney and less ad- 

 vanced in others closely adjacent to the first, the surface becomes 

 studded with small nodules, some of the size of a pin's head, and 

 some as large as a pea. Hence the term granular kidney. Such a 

 kidney is very hard and tough. Upon section, the cortical substance 

 is often found to be so much wasted that the secreting parenchyma 

 only forms a narrow rim around the pyramids, while the latter are 

 often but little reduced in size, being but sligthly affected by the 

 disease. Certain whitish stripes sometimes observed correspond to 

 the straight tubules which have become obliterated for want of sup- 

 ply of secretion. The general diminution of the kidney, with atro- 

 phy of many of its glomeruli and tubules, is always in the main as- 

 cribable to the compression exerted by the contracting newly-formed 

 connective tissue ; but other factors also contribute to this, such as 

 wasting of the epithelium and urinary tubules. It is sometimes 

 found that the process of thickening of the tissues is much more 

 pronounced in the Malpighian capsules and their vicinity ; or, on 

 the other hand, the greatest change may be in the tunica propria of 

 the tubules and in the connective tissue between them. Accord- 

 ingly, Traube distinguishes two forms of interstitial nephritis, the 

 circumcapsular and the intratubular, each of which presents certain 

 peculiarities from a clinical point of view. Not unfrequently, in 

 the cortical substance we find numerous small cysts having clear 

 contents, and varying in size from that of a millet-seed to that 

 of a pea. These probably are the product of constriction and dila- 

 tation of parts of a uriniferous tubule, particularly of one of the 

 convoluted tubes. 



The chronic parenchymatous form is regarded by some observ- 

 ers as an inflammation which occurs exclusively and entirely in the 

 secretory cells of the tubules. We do not hold it proved that there 

 is such a form, and think that there may be confusion with the so- 

 called "opaque swelling" of the kidney epithelium (Chapter VIII. ). 

 But we find that in some cases the elements of the tubules take 



