THE URINE. 427 



so-called mucus, a few epithelium-cells, mucous corpuscles, and 

 urate particles. If an acid urine is allowed to stand it will gradu- 

 ally change ; it becomes darker and deposits a sediment consisting 

 of uric acid or urates and sometimes also calcium-oxalate crystals, 

 in which yeast-i'uugus and bacteria are often to be seen. The 

 cause of this change, which the earlier investigators called " ACID 



FERMENTATION OF THE URINE," is, according to SCHERER, the 



mucus, which acts like an enzyme or ferment, producing an acetic- 

 acid or lactic-acid fermentation, precipitating free uric acid or acid 

 urates. According to NEUBAUER, an actual acid fermentation may 

 occur in diabetic urine, but this change in the urine is now 

 generally explained in other ways. According to VOIT and HOF- 

 MANN, a separation of free uric acid and acid urates may be pro- 

 duced without any increase in the acid reaction, by an exchange of 

 the di-hydrogen alkali phosphates with the alkali urate on cooling 

 and on standing. Simple acid phosphate and, according to the 

 conditions, acid urate or free uric acid are formed. A gradual pre- 

 cipitation of uric acid may occur not only without an increase in 

 the acid reaction, but, because of the alkaline reaction of the 

 di-alkali phosphate, it may occur with a simultaneous decrease of 

 the same. 



Earlier or later, sometimes only after several weeks, the reaction 

 of the original acid urine changes and becomes neutral or alkaline. 

 The urine has now passed into the "ALKALINE FERMENTATION," 

 which consists in the decomposition of the urea into carbon dioxide 

 and ammonia by means of lower organisms, micrococcus urese, 

 bacteria ureae, and other bacteria. MUSCULUS has isolated an 

 enzyme from the micrococcus ureas which decomposes urea and is 

 soluble in water. During the alkaline fermentation volatile fatty 

 acids, especially acetic acid, may be produced, chiefly by the fer- 

 mentation of the carbohydrates of the urine (SALKOWSKI). 



If the alkaline fermentation has only advanced so far as to 

 render the reaction neutral, then we often find in the sediment 

 fragments of uric-acid crystals, sometimes covered with prismatic 

 crystals of alkali urate; dark-colored globules of ammonium urate, 

 often crystals of calcium oxalate, and sometimes crystallized cal- 

 cium phosphate are also found. Crystals of ammonium-magnesium 

 phosphate (triple phosphate) and globules of ammonium urate are 



