282 DR. ROBERTS ON THE DIURNAL 
per 1000. The mean acidity, taking all the hours during 
which the urine flowed acid, was 1:13 per 1000; if the 
hours of sleep, the two hours before dinner and the 
hour before breakfast be excluded, the mean acidity for 
the remaining hours of the acid flow falls to about 0°80 
per 1000. 
The amount of free alkali passed in the twenty-four hours 
varied according to the duration and intensity of the alka- 
line tide. On the nineteen days represented in Tables 
I., IIL., XI. and XV. the urine was alkaline, on an aver- 
age, for more than three and half hours each day, and 
contained a quantity of free alkali equal in saturating 
power to 3°32 grains of dried carbonate of soda. The 
mean quantity discharged per twenty-four hours, with 
mixed food, was 4°14 grains for the first set and 4°72 
grains for the second (Tables I. and III.) ; for vegetable 
food, 1:71 grains (Table XI.) ; and for animal food, 1-68 
grains (Table XV.) 
The numbers for the separate days ranged from zero to 
9°35 grains, and great irregularities prevailed throughout, 
even when the days were consecutive and the diet the 
same. 
It is to be remarked that the days of mixed diet showed 
a greater discharge of free alkali than those of purely 
animal or purely vegetable diet. This corresponds with 
the lower figure representing the free acid on those days. 
The hourly discharge of free alkali oscillated from 0-00 
to 2°60; and it usually ranged between 0°50 and 1:00. 
The degree of alkalinity per 1000 grains varied also in 
the same manner. The highest grade observed was 4:12; 
but the usual numbers were from 0°40 to 1:60. 
In comparing the effects of the three different kinds of 
diet it must be owned that the results are very contradic- 
tory. In the first set of experiments on vegetable food 
the urime did not once become alkaline (Table IX.) nor 
