PROPERTIES OF THE TJKINE. 189 



in health are between twenty-ssven and fifty fluidounces ; * 

 but his average of the total quantity in the twenty-four hours 

 is only forty-four ounces, which is rather lower than the one 

 we are disposed to adopt. The circumstances that lead to a 

 diminution in the proportion of water are usually more effi- 

 cient in their operation than those which tend to an increase ; 

 and the range below the healthy standard is rather wider 

 than it is above. All these estimates, however, are merely 

 approximative. Assuming that the usual quantity in the 

 male is about fifty ounces, it may be stated, in general terms, 

 that the range of normal variation is between thirty and 

 sixty ; and that when the quantity varies much from these 

 figures, it is probably due to some pathological condition. 



According to the researches of Becquerel, the quantity 

 of water discharged 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 amount of solid 

 constituents is relatively and absolutely less. 2 



The specific gravity of the urine should always be 

 estimated in connection with the absolute quantity in the 

 twenty-four hours. Those who assume that the daily quan- 

 tity is about fifty ounces give the ordinary specific gravity 

 of the mixed urine of the twenty-four hours, at 60 Fahr., as 

 about 1020. The specific gravity is liable to the same vari- 

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

 precisely as the amount of water is diminished. The ordi- 

 nary range of variation in specific gravity is between 1015 

 and 1025 ; but without positively indicating any pathologi- 

 cal condition, it may 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 is usually 

 acid at the moment of its discharge from the bladder ; though 

 at certain periods of the day it may be neutral or feebly 



1 BECQUEREL ET RODIER, Traite de chimie pathologique appliquee d la medecint 

 pratique, Paris, 1854, p. 273. 



8 BECQUEREL ET RODIER, op. tit., p. 270, table. 



