782 DE. SMITH OH THE ELIMINATION 
analyses throughout the year. It should also be noticed, in reference to the amount of 
urine emitted on the same day, that whilst on the average it was scarcely higher than 
the average of the year, the list comprehends twenty-one occasions on which the quantity 
exceeded 60 ounces. 
On turning to the exceptions in the relation of the basis quantity of urea with the 
night urine, it is seen that the defect in the quantity of urine emitted, both on the pre- 
ceding and on the same day on which the defect in the basal quantity of urea occurred, 
is quite as marked as is the excess of urine in relation to excess of the basal quantity of 
urea ; for the average was below that of the whole year, and the list comprehends a large 
proportion of the days of unusually small emission of urine. 
Hence it is shomi that, although the “ basis quantity” of urea is on the whole average 
greater than the night and less than the day quantities, it has a marked tendency to 
become in excess whenever the quantity of urine is increased, and to be in defect when 
the quantity of urine is diminished. After a laborious analysis of the returns, and a 
careful consideration of the subject, I fear that there is not any period of the day at 
which a standard excretion of urea may be established for short periods, and that the 
determination of this basis quantity will aid but little as a measure of the vital actions 
proceeding in the body. 
The monthly and A"/?/ averages of the rate of excretion of urea before midday, with 
but one exception, conformed to the rule established by the yearly average. The excess 
in this quantity over the daily average varied in ditferent weeks from 0 to 8-6 grs. per 
hour. In the instance which forms the exception, this morning rate was equal to that 
of the whole day, and was caused by a reduction of the rate on one day from an attack 
of dian’hoea, which occurred in the morning hours. There were also three exceptions 
in the weekly averages ; but two of these involved only the second place in decimals, 
and the last was deficient to the extent of 2 grs, per hour. With all these exceptional 
conditions, there w’as associated a remarkable diminution in the quantity of urine voided 
during the morning hours. 
The relative position of the excretion of urea in the morning hours, in reference to 
the other periods now referred to, is thus well established. 
I determined the rate of the excretion of urea during the afternoon at intervals of 
two or three hour's in the month of February 1860, and have stated the results in a 
few cases in Table XVI. There are variations on the different days ; but they do not 
affect the general direction of the curves, so that all agree in showing that there is a 
large and rapid increase in the elimination of urea in the morning hours, followed by 
a gradual decline as the afternoon advances. The hour of maximum elimination was 
commonly from midday to 2 p.m.; but sometimes it was so early as 10 a.m., and so late 
as 4 P.M. There was frequently seen an attempt at increase in the middle of the after- 
noon, and this will be further elucidated when we describe the results of the next series 
of inquiries ; but in the instance of February 17 this tendency was so exaggerated as to 
cause the maximum elimination to occur at that period, a circumstance w'hich was due 
