VARIATIONS IN THE ACIDITY OF THE URINE. 27 
Or 
one occasion five hours. The amount of free alkali hourly 
discharged after dinner was, generally, not far from double 
the quantity observed after breakfast; so that in duration 
and intensity the effect of dinner proved about twice as 
great as that of breakfast. 
The Alkaline Urine of Food. 
The alkaline urine which followed the taking of food 
deserves special description. It is important, in the first 
place, to state that its alkalescence did not depend upon 
ammonia, but upon a fixed alkali. It had no ammoniacal 
smell; caustic potash failed to evolve any; and the phos- 
phates which were thrown down in it did not, when freshly 
passed, contain any crystals of the ammoniaco-magnesian 
phosphate. Under the microscope the fresh deposit was 
always found to be amorphous. No effervescence could 
ever be observed in the urine on the addition of hydro- 
chloric acid. As might have been anticipated, the occur- 
rence of an alkaline reaction determined the precipitation 
of the earthy phosphates, and the urine, when passed, 
was frequently turbid. But this was not always so. Not 
unfrequently, especially after breakfast, the urine, al- 
though alkaline, retained its transparency. Generally 
such a urine was of feeble alkalinity and dilute; but now 
and then it was observed to be tolerably concentrated, 
highly alkaline, and still clear. All transparent alkaline 
urines were rendered immediately turbid by caustic am- 
monia and by heating, so that the transparency did not 
depend on the absence of earthy phosphates. It was 
also found that, in the turbid urines after subsidence of 
their deposits, caustic ammonia caused an additional pre- 
cipitation. 
Out of twenty-eight specimens of alkaline urine after 
breakfast, nineteen were more or less turbid and nine 
clear. Of sixty-four specimens alkaline after dinner, fifty- 
one were turbid and thirteen clear. The proportion of 
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