TUBE CASTS IN UEINE. 



417 



D. Spermatozoa may be present. 



E. Lower organisms occur in the urinary passages very seldom, but they may be present, 

 e.g., in the bladder, when germs are introduced from without by means of a dirty catheter. 

 [Before introducing a catheter into the bladder one ought always to make sure that the instru- 

 ment is perfectly aseptic] Micrococci are found in the urine in certain diseases, e.g., 

 diphtheria. The following forms are distinguished : 



1. Schizomycetes ( 184). Normal human urine contains neither schizomycetes nor their 

 spores. In pathological conditions, however, fungi may pass from the blood into the urinary 

 tubules and thus reach the urine (Leube). During 

 the alkaline fermentation of urine, micrococci, 

 rod-shaped bacteria or bacilli (fig. 273) appear. 

 Sarcinae belong to the group ( 186). 



2. Saccharomycetes (fermentation fungi) : (a) 

 The fungus of the acid urine fermentation (S. 

 urinse) consists of small bladder-like cells arranged 

 either in chains or in groups (figs. 260, a ; 273, /). 

 (b) Yeast (S. fermentum) occurs in diabetic urine, 

 as oval cells with a dotted eccentrically-placed 

 nucleus (fig. 237). 



3. Phytomycetes (moulds) occur in putrid urine * ' ' 



(fig. 273, e). They are without clinical signifi- Fungi in urine, e, mould ; /, yeast ; d, g, 

 cance. micrococci and bacilli ; a, b, c, uric acid. 



F. Tube Casts. The occurrence of tube casts, i.e., casts of the uriniferons tubules (Henle, 

 1837), is of great importance in the diagnosis of renal diseases. If these structures are relatively 

 thick and straight, they probably come from the collecting tubules, but if they are smaller and 

 twisted, they probably come from the convoluted tubules. There are various forms of tube 



casts : 1. Epithelial casts, consisting of the actual cells of the uriniferous tubules. 

 They indicate that there is no very great change going on, but only that, as in 

 catarrhal inflammation of any mucous membrane, the epithelium is in process of 

 desquamation. 2. Hyaline casts (fig. 280) are quite clear and homogeneous, usu- 

 ally long and small; sometimes they are "finely granular," from the 

 ^ presence of fat or other particles. They are best seen after the addition 

 solution of iodine. They are probably formed from albumin, which 



Fig. 276. 

 -Epithelial casts. Fig. 275. Blood cast. Fig. 276. Leucocyte cast. 

 Acid sodic urate in cylinders. Fig. 278. Finely granular cast. 



Fig. 275 



passes into the uriniferous tubules. They are dissolved in alkaline urine, while acid urine 

 favours their formation. They usually occur in the late stages of renal disease, after the 

 tubular epithelium has been shed. 3. Coarsely granular casts (fig. 279) are brownish- 

 yellow, opaque, and granular, usually broader than 2. There are various forms. Not unfre- 

 quently there are fatty granules, and, it may be, epithelial cells in them. 4. Amyloid casts 

 occur in amyloid degeneration of the kidneys (fig. 280). They are refractive and completely 

 homogeneous, and give a blue colour (amyloid reaction) with sulphuric acid and iodine. 5. Blood 

 casts occur in capillary haemorrhage of the kidney, and consist of coagulated blood entangling 

 blood- corpuscles (fig. 275). "When tube casts are present, the urine is always albuminous. 



Leucocyte casts occur in suppurating conditions of the urinary tubules (fig. 280). The urates 

 in the form of casts (fig. 277) are without significance. 



II. Unorganised Deposits. 



Some of these are crystalline and others are amorphous, and they have been referred to in 

 treating of the urinary constituents. 



2d 



