762 THE URINARY TRACT. 



a severe degree of inflammatory changes which, on account of the presence 

 of the casts within the tubules, might be called croupous, in the sense of 

 Henle and Traube. 



The condition of the kidney of a man, thirty-seven years of age, who died 

 with symptoms of uraemia, on the sixth day after the extirpation of an orbital 

 tumor, is the following : The kidneys increased in size by one-half their bulk, 

 rich in blood, of a doughy softness ; the capsule easily stripped ; the surface 

 markedly injected ; the cortical substance twice as broad as normal ; the border 

 toward the pyramids indistinct. The whole tissue, especially that of the corti- 

 cal substance, of a nearly homogeneous, grayish-red color, evacuating a thick, 

 grayish-red, cloudy fluid when its cut surface is scraped with the knife. The 

 glomeruli appear enlarged, even to the naked eye, and are of a dark red color. 

 Under the microscope the blood-vessels appear dilated, partly filled with 

 blood. The arteries (especially their middle coat), are widened, the muscle- 

 fibers in part coarsely granular, in part converted into homogeneous, shining 

 layers. The glomeruli universally enlarged, their vascular loops dilated, the 

 vascular walls shining and nearly homogeneous ; the connective tissue between 

 the loops widened, provided with shining granules and lumps. The capsule 

 and the interstitial connective tissue have for the most part lost their striated 

 character, and appear granular, dotted with numerous, partly homogeneous, 

 partly coarsely granular lumps. 



The urinary tubules present changes, as in catarrhal inflammation the 

 convoluted tubules enlarged and wound; their epithelia in a condition of 

 1 ' cloudy swelling," in part detached from the wall, and lying free* in the 

 lumen; in many places the epithelium broken up into yellowish, shining 

 lumps. Moreover, the epithelia of many convoluted and straight tubules pre- 

 sent changes which must be regarded as characteristic of croupous inflam- 

 mation. . The epithelia are swollen up to a complete closure of the lumen ; 

 they are converted into globules or plates of a faint luster, which, partly coa- 

 lescing, represent irregular, caky masses. Finally, all the epithelia of a tubule 

 appear changed into such a mass, in which even the outlines of the former 

 epithelia are recognized ; these are the tubular casts. Hyaline or finely 

 granular casts are colorless in the fresh state, and are readily stained by car- 

 mine, while, more particularly in .the narrow tubules, granular, yellowish plugs 

 occur which do not imbibe the carmine. Since plugs of the latter kind are 

 also to be observed in blood-vessels, nay, even in single loops of the tufts, 

 there can be no doubt that they are albuminates, being essentially the same 

 as the fluid portion of the blood, and stained yellow by the coloring matter of 

 the blood. Wherever the epithelium has gone through the process described, 

 small, shining, spindle-shaped projections are visible on the membrana pro- 

 pria, in part distinctly separated from the caky mass ; and where the forma- 

 tion of a hyaline cast is complete, we almost constantly meet with a narrow 

 epithelial layer, composed, in the optical section, of spindles. 



Many convoluted tubules contain hyaline casts, the epithelium of the 

 tubules being only slightly changed or desquamated. It is probable that these 

 are casts which have not been formed in situ, but were washed down. Where 

 the cast adheres closely to the wall, the epithelia are either not recognizable, 

 or we see irregular projections of the wall or flat bodies quite irregularly 

 arranged. (See Fig. 344.) 



How did the casts originate f Since changes such as described in the epi- 

 thelia of the uriniferous tubules occur also in the interstitial connective 

 tissue, and even in the blood-vessels, there can be no doubt that the exuda- 



