VARIATIONS IN THE ACIDITY OF THE URINE. 269 
shall find that the fall after breakfast is brought out in its 
true prominence, as the following table shows. 
TABLE XVIII. The first column is a transcription of the 
hourly discharge of acid from Table IX. The second column 
shows the per-centage of acid on the solids at successive hours 
Srom seven a.m. to four p.m. (Breakfast at Eight). 
Pe Acid corres- 
Acid discharged ponding to 100 
Time of day 
per hour grains of solids 
7-8 1:20 3°87 
8-9 1°35 2°87 
9-10 114 2°11 
10-11 1:00 1:72 
11-12 119 2°12 
12-2 1:32 2°32 
2-4 1:30 3°82 
By this table it is made evident that the solid constitu- 
ents of the urine, or what, for brevity, may be called the 
solid urine, became steadily less and less acid after break- 
fast until eleven o’clock ; from that time its acidity rose 
as steadily until dinner. At eleven o’clock the solid urine 
had less than one-half the acidity it possessed before 
breakfast, or just before dinner. 
The same result is brought out after dinner, and in 
about the same degree. Taking the two hours before 
dinner, and the sixth and seventh hours after dinner, 
every 100 grains of solid residue had an acidity of 3°65; 
whereas during the third and fourth hours after dinner 
(the period of the supposed alkaline tide) the solid residue 
of the urine had but 1°82 per cent. of acid. 
The apparently exceptional cases, where meals do not 
appear to lower the acidity at all, or where the hourly dis- 
charge rises even for a while after a meal, are thus made 
conformable to the general result. The taking of a meal 
greatly increases the excretion of solids by the kidneys; 
and even if these be of diminished acidity, the quantity 
passed per hour may overbalance this diminution, and, 
for a while, actually cause an increased hourly discharge 
