434 



EXCRETION 



urines, and which is especially abundant in the urines passed by febrile 

 patients. It is characterized by a well-marked spectroscopic absorption 

 band at the junction of green and blue. Those who believe urobilin to 

 be identical with hydrobilirubin suppose that the bilirubin is reduced by 

 the putrefactive processes in the intestines, and is conveyed in its reduced 

 form by the blood stream to the kidneys. 3. Uroerythrin, occasionally 

 found. 



Mucus. Mucus sediment in the urine consists principally of mucin and 

 of the epithelial debris from the mucous surface of the urinary passages. 

 Particles of epithelium, in greater or less abundance, may be detected in most 

 samples of urine, figure 297. As urine cools, the mucus is sometimes seen 

 suspended in it as a delicate opaque cloud, but generally it falls. In inflam- 

 matory affections of the urinary passages, especially of the bladder, mucus 

 is secreted in large quantities. 



FIG. 287. FIG. 298. 



FIG. 297. Urinary Deposit of Mucus, etc. 



FIG. 298. Urinary Sediment of Triple Phosphates (large prismatic crystals) and 

 Urate of Ammonium, from urine which had undergone alkaline fermentation. 



Saline Matter. Sulphuric acid, in the form of salts, is taken in very 

 small quantity with food. Sulphur is also a constituent part of the protein 

 molecule ; hence its elimination, like that of nitrogen, gives a certain measure 

 of protein metabolism. It is excreted as inorganic sulphates of sodium and 

 potassium, and as eth eal sulphates, compounds of phenol, cresol, skatol, 

 i.e., cresol sulphuric acid (C 7 H 7 OSO 2 OH), etc. 



The phosphoric acid in the urine is combined partly with the alkalies, 

 partly with the alkaline earths, about four or five times as much with the 

 former as with the latter. In blood, saliva, and other alkaline fluids of the 

 body phosphates exist in the form of alkaline, neutral, or acid salts. In the 

 urine they are acid salts, viz., the sodium, ammonium, calcium, and magne- 

 sium phosphates, the excess of acid being (Liebig) due to the appropriation 

 of the alkali with which the phosphoric acid in the blood is combined, by 

 the several new acids which are formed or discharged at the kidneys, 

 namely the uric, hippuric, and sulphuric acids. 



