VARIATIONS IN THE ACIDITY OF THE URINE. 267 
their urine resumed its natural clearness and acid re- 
action. 
It is more easy to reconcile the experiments detailed in 
the preceding pages with the first of these considerations 
than with the second. All food was found essentially to 
affect the reaction of the urine alike, but, contrary to what 
one would expect, animal food produced usually a stronger 
and more enduring impression than vegetable food. Yet 
it may be pointed out as worth notice, that of the three 
consecutive days of exclusively animal and exclusively 
vegetable diet, the greatest effect in the former was on 
the first day, and it fell progressively on the second and 
third days; whereas the reverse took place on the days of 
vegetable food. On the first day the urine did not be- 
come alkaline at all; on the second it was neutral after 
breakfast and alkaline for two hours after dinner; on 
the third day it was strongly alkaline for an hour after 
breakfast and for three hours after dinner. 
Ordinary food, whether it was purely animal, purely 
vegetable, or, as was more usual, an admixture of the two, 
was invariably found to cause a diminution in the amount 
of acid separated by the kidneys. In the tables there is 
record of thirty-two days on which the urine was examined 
both after breakfast and after dinner (with the exception 
of one day on which the observations did not commence 
until after dinner); and I have notes, in addition, of the 
state of the urine on five other days after breakfast and 
on four days after dinner. The following table shows how 
often the urine became neutral or alkaline, or sustained 
its acidity, after these two meals, with various kinds of 
food. 
VOL. XV. NWN 
