PROPERTIES AND COMPOSITION OF THE URINE 337 



land, France and Germany, and found the average daily quantity of 

 urine in healthy male adults, between twenty and forty years of age, to be 

 fifty-two and a half fluidounces (1552.6 cubic centimeters), the average 

 quantity per hour being two and one-tenth fluidounces (62 cubic centi- 

 meters). The extremes were thirty-five ounces and eighty-one ounces 

 (1035 and 2395 cubic centimeters). The average quantity may be 

 assumed to be about fifty-one fluidounces (1500 cubic centimeters). 

 The normal range of variation is between thirty and sixty ounces (about 

 900 and 1775 cubic centimeters). The conditions which lead to a dimi- 

 nution in the quantity of urine usually are more efficient in their opera- 

 tion than those which tend to an increase; and the range below the 

 normal standard is rather wider than it is above. More urine usually 

 is secreted during the day than at night. The quantity of water dis- 

 charged by the kidneys in the twenty-four hours is a little greater in 

 the female than in the male ; but in the female the specific gravity is 

 lower, and the quantity of solid constituents is relatively and absolutely 

 less. 



The specific gravity of the urine should be estimated in connection 

 with the absolute quantity in the twenty-four hours. Those who assume 

 that the daily quantity is about fifty-one ounces (1500 cubic centimeters), 

 give the ordinary specific gravity of the mixed urine of the twenty-four 

 hours as about 1020. The specific gravity is liable to the same varia- 

 tions as the proportion of water, and the density is increased as the 

 water is diminished. The ordinary range of variation in specific gravity 

 is between 1015 and 1025 ; but without positively indicating a pathologi- 

 cal condition, it may temporarily be as low as 1005 or as high as 1030. 



The reaction of the urine is acid in the carnivora and alkaline in 

 the herbivora. In the human subject it usually is acid at the moment 

 of its discharge from the bladder ; although at certain times of the day 

 it may be neutral or feebly alkaline, the reaction depending on the 

 character of food. The acidity may be measured by neutralizing the 

 urine with an alkali in a solution that has previously been graduated 

 with a solution of oxalic acid of known strength ; and the degree of 

 acidity usually is expressed as equivalent to so many grains of crystal- 

 lized oxalic acid. 



The total quantity of acid in the urine of the twenty-four hours in 

 a healthy adult male is equal to between thirty and sixty grains (2 and 

 4 grams) of oxalic acid. The hourly quantity in the observations of 

 Vogel was equal, in round numbers, to between one and a half and three 

 grains (o.i and 0.2 gram) of acid. The proportion of acid was found to 

 be variable in the same person at different times of the day. The urine 

 contains no free acid, but its acidity under an animal or a mixed diet 



