798 
DE. SMITH ON THE ELIMINATION 
uniformity than was found in reference to the urea. The quantity eliminated in March 
1860 was 51T6 oz. daily, and this progressed through 54*42, 45*53, 53*03, 55*3, and 
60*1 to the maximum of 64*6 oz. daily in September, and then fell through 56, 51*7, 
50*17 to 47*87 in January, and rose to 52*9 and 53*8 in February and March 1861. 
Tlie progression was thus broken by the diminished rate in May and January, and the 
increase began so early as February; but the maximum quantities were found at the 
period of maximum elimination of urea. On dividing the year into two parts, as above 
indicated, when speaking of urea, we find that the elimination of urinary water was 55*7 
oz. daily in the warm, and 51*9 oz. daily in the cold season. The excess of the maximum 
over the minimum monthly rate v/as 40*2 per cent, of the latter. [In 1861 and 1862 
the maximum quantity of 57 oz. occurred in the month of September, and in the 
months of June, July, and August the quantities were less than those recorded in 1860. 
On the division of the year into two parts the quantity was precisely equal in each, viz. 
49*3 fiuid ounces.] 
Causes of Seasonal variation. 
Temper cdiire . — Kaupp, in numerous experiments made at various temperatures, found 
that the quantity of urinary water, urea, chloride of sodium, and, indeed, both solids and 
liquids diminished as the temperature increased, and he attributed the diminution of 
the solid excretions to the lessening of the urinary water. Lehmann found that mode- 
rate cold increased, but great cold decreased the urinary excretion. 
I have not made any experiments with artificial temperatures, or for short periods, 
or with any regulated or standard dietary to be used under varying conditions, but 
have 'ascertained the efiect of seasonal variations of temperature with the ordinary 
variations of food. I was not able to determine the amount of food taken in August 
and September ; but, being then at the sea-side, it is more than probable that it was 
increased. Hence it is highly probable that the observations hitherto recorded and 
those now to be mentioned have not been made under parallel conditions ; and the 
results may be due to different causes, although associated with temperature. 
It is also necessary to bear in mind that the mean external temperature very imper- 
fectly represents the true temperature in which we live during the greater part of the 
twenty-four hours, and particularly in the winter, and also that other causes exert 
influences which may correspond with or be opposed to those of temperature. Hence 
the inquiry is a most difficult oiie. 
The general influence of temperature is evident from the foregoing statement ; for 
the lines of temperature and urea were parallel throughout the year. The average 
temperatures of the two periods of the year were 55° and 44°, corresponding with 570 grs. 
and 480 grs. of urea daily, which gives the very uniform proportion of 10*36 grs. and 
10*9 grs. of urea to each degree of temperature on the average of the two opposite 
seasons. Moreover, the month (May) of marked increase in the urea (56*5 grs.) was 
that of marked increase of temperature (10°*9) ; whilst that (November) of marked 
decrease (63 grs.) was also that of great decrease of temperature (9°*65). As the pro- 
