68 



is credited in 1842, with first carefully describing the casts 

 moulded in the tubules of the kidneys. Among earlier views, 

 casts were considered as being composed of coagulated fibrin; 

 as products of the secretion of the epithelium of the tubules; as 

 transformed or disintegrated epithelial cells and as products 

 from the blood. A view quite commonly accepted is that casts 

 are the products of the coagulation of albuminous material. The 

 fact that the presence of casts in the urine is usually accompanied 

 by the presence of albumin lends 

 force to this view; for the more 

 abundant the albumin, the more 

 likelihood is there of finding casts. 

 From this standpoint, then, casts, 

 may be regarded as albuminous 

 exudates from the blood, with the 

 addition of transformed or de- 

 stroyed epithelium. In nearly all 

 cases where casts are present, 

 some albumin is found. Occasion- 

 ally they are sometimes described 

 as being present without the ap- 

 pearance of albumin. This condi- 

 tion is looked upon with some 

 doubt ; for it is commonly be- 

 lieved that albumin exists but in 

 an amount too slight to be detected by the ordinary chemical 

 tests. 



The presence of casts in the urine is of much diagnostic im- 

 portance ; if found in any quantity, they indicate nephritis par- 

 ticularly if albumin is also present in any amount. It is claimed 

 by some that merely hyperemia of the kidney will cause the 

 appearance of casts in the urine, and that they may sometimes be 

 found when the kidneys are perfectly intact. Mitchell states 

 that two or three hyaline or one or two small granular casts may 

 be found in one of every three specimens of the twenty-four 

 hour's urine examined (human). Casts have been described in 

 eases of gastro-intestinal catarrh, in jaundice, in acute and 

 chronic anemia, as well as in nervous affections of different kinds, 

 without accompanying inflammation of the kidneys. There are 



Fig. 23. a. Showing forma- 

 tion of hyaline cast in tubule, 

 b. Hyaline cast with granular 

 deposit, c. Granular cast. 



