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9. The alkaline urine after a meal owed its reaction to a 
fixed alkali. It did not contain ammonia. Generally it was 
turbid from precipitated phosphates when passed; but not 
unfrequently, however, it was clear, and once or twice it was 
clear when strongly alkaline. Its odour was very peculiar, 
and resembled exactly that of the urine of the horse. It was 
found rich in uric acid, also in earthy phosphates, the alkaline 
phosphates seemed only moderately abundant in it. 
10. The emission of urine, turbid with phosphates, is there- 
fore, within certain limits, a natural phenomenon, and earthy 
phosphates are the only urinary deposits which can appear 
in the urine before cooling, in the healthy state. 
11. The depression of the acidity after a meal coincides in 
point of time with chymification rather than with digestion. 
The solids of the urine began to increase simultaneously with 
the declension of its acidity. So that the passage of food into 
the blood, and the diminished acidity of the urine seemed to 
be connected together as cause and effect. 
12. Liebig has pointed out that phosphoric acid and the 
alkalies are present in such proportion in bread, meat, and our 
ordinary food, that if w^e su])pose them dissolved, the alkalies 
invariably preponderate. Hence arises, he says, the alkalinity 
of the blood.* If this be so, every meal that is dissolved and 
absorbed into the blood must increase the alkalinity of that 
fluid, and raise it for a time above the natural level. But it 
is well known that the kidneys are the unique channel by 
which fixed alkalies given as medicines pass through the 
system, and in their traject they render the urine alkaline. 
And what is a meal, viewed in this light, but a dose of 
alkali? This explanation accords perfectly with the state- 
ment in proposition 11. 
Dr. Joule having taken the Chair, a Paper was read by 
the President, W. Fairbairn, F.R.S., entitled “ Experiments 
* “Fiiinilin- Letters,” letter 28. 
