THE URINARY TRACT. 769 



I am able to corroborate the statement made by A. Meyer, that in the 

 process of catarrhal nephritis in the cortical substance many tubules are 

 destroyed, and that their epithelia, after a considerable increase of living 

 matter, break down into medullary corpuscles, from which a new formation of 

 connective tissue subsequently arises. This destructive process in chronic 

 catarrhal nephritis invades first and in the highest degree the narrow 

 tubules running in the medullary rays. By a swelling of the epithelia the 

 calibers of the tubules are obliterated, the epithelia then break down and 

 form rows of medullary corpuscles. A corresponding change takes place in 

 the capillary blood-vessels in the neighborhood. These metamorphoses result 

 in the formation of a tissue, which, from the presence of basis-substance, 

 must be regarded as connective tissue, though it rarely becomes fibrous, and 

 the vascular supply is always scanty. If a number of tubules in the medullary 

 rays are involved in this destructive process, the surface of the kidney corre- 

 sponding to them will be retracted by the cicatricial tissue. 



The obliteration of a number of the narrow tubules, including the ascend- 

 ing and descending branches, would explain the clinical fact that persons 

 affected with cirrhosis void large quantities of urine almost destitute of salts. 

 We know, from the results of Bowman's investigations, which have recently 

 been corroborated by R. Heidenhain, that the tuft excretes water only, and 

 this becomes thicker by the addition of the saline constituents excreted by 

 the narrow tubules. It is in the narrow tubules that much of the watery part 

 of the urine is restored to the thickened blood which runs in the neighbor- 

 ing capillaries, including also the vasa recta of the pyramids. If the function 

 of the tubules be much interfered with, the interchange between the liquid 

 contents of the tubes and the solid constituents of the blood will not 

 take place, and consequently the urine will be voided in about the same con- 

 dition in which it was pressed into the capsule from the tuft. Numbers of 

 the convoluted tubules perish also through the increased formation of connec- 

 tive tissue, while from others the epithelia are simply desquamated, and, 

 together with pus-corpuscles, which are the offspring of epithelia, appear in 

 the urine. Both the quantity and the character of the urine, as well as its 

 morphological elements visible under the microscope, enable us with cer- 

 tainty to make a diagnosis of cirrhosis of the kidney. 



From the above description it is evident that interstitial and desquama- 

 tive nephritis are concomitant features of chronic catarrhal nephritis, and 

 that the latter expression includes the two former. 



In high degrees of cirrhosis many of the tufts are completely destroyed. 

 I have been able to trace the changes by which the destruction is brought 

 about. At first the tuft appears slightly enlarged and crowded with bodies 

 having the appearance of nuclei, and which undoubtedly originated from 

 the covering epithelia and from the endothelia of the capillary walls. By 

 this process the calibers of the vessels are obliterated, and all that remains 

 of the former capillaries is a solid cord. Next the solidified capillaries break 

 down into medullary or inflammatory corpuscles, and in this stage the tuft 

 consists of an aggregation of inflammatory corpuscles. The capsule is usually 

 considerably thickened, and between it and the inflammatory bodies no 

 space can be recognized. In the succeeding stage the medullary corpuscles 

 are transformed into homogeneous or faintly striated connective tissue 

 containing only a very limited number of plastids. 



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