ALKALINE FERMENTATION OF THE URINE. 361 



may be afterward kept, for an indefinite time, without alteration. 

 But under ordinary circumstances, the mucus, as soon as its putre- 

 faction has commenced, excites the decomposition of the urea, and 

 carbonate of ammonia begins to be developed. 



The first portions of the ammoniacal salt thus produced begin to 

 neutralize the biphosphate of soda, so that the acid reaction of the 

 urine diminishes in intensity. This reaction gradually becomes 

 weaker, as the fermentation proceeds, until it at last disappears 

 altogether, and the urine becomes neutral. The production of 

 carbonate of ammonia still continuing, the reaction of the fluid 

 then becomes alkaline, and its alkalescence grows more strongly 

 pronounced with the constant accumulation of the ammoniacal salt. 



The rapidity with which this alteration proceeds depends on the 

 character of the urine, the quantity and quality of the mucus which 

 it contains, and the elevation of the surrounding temperature. The 

 urine passed early in the forenoon, which is often neutral at the 

 time of its discharge, will of course become alkaline more readily 

 than that which has at first a strongly acid reaction. In the summer, 

 urine will become alkaline, if freely exposed, on the third, fourth, 

 oj fifth day ; white in the winter, a specimen kept in a cool place 

 may still be neutral at the end of fifteen days. In cases of paralysis 

 of the bladder, on the other hand, accompanied with cystitis, where 

 the mucus is increased in quantity and altered in quality, and the 

 urine is retained in the bladder for ten or twelve hours at the tem- 

 perature of the body, the change may go on much more rapidly, so 

 that the urine may be distinctly alkaline and ammoniacal at the 

 time of its discharge. In these cases, however, it is really acid 

 when first secreted by the kidneys, and becomes alkaline while 

 retained in the interior of the bladder. 



The first effect of the alkaline condition of the urine, thus pro- 

 duced, is the precipitation of the earthy phosphates. These salts, 

 being insoluble in neutral and alkaline fluids, begin to precipitate as 

 soon as the natural acid reaction of the urine has fairly disappeared, 

 and thus produce in the fluid a whitish turbidity. This precipitate 

 slowly settles upon the sides and bottom of the vessel, or is partly 

 entangled with certain animal matters which rise to the surface and 

 form a thin, opaline scum upon the urine. There are no crystals 

 to be seen at this time, but the deposit is entirely amorphous and 

 granular in character. 



The next change consists in the production of two new double 

 salts by the action of carbonate of ammonia on the phosphates of 



