QUANTITATIVE COMPOSITION. 771 



eliminated in twenty-four hours; therefore the quantity of solids excreted was 



48 9 X 1050 



21 X 2.33 =48.9 and "Tonn =51.35 grams. LONG l has made a new determina- 

 tion of the coefficient for the specific gravity taken at 25 C. and finds that it is 

 equal to 2.6, which almost corresponds to HASER'S coefficient at 15 C. 



Those bodies which, under physiological conditions, affect the density 

 of the urine are common salt and urea. The specific gravity of the first 

 is 2.15 and the last only 1.32, so it is easy to understand, when the relative 

 proportion of these two bodies essentially deviates from the normal, 

 why the above calculation from the specific gravity is not exact. The 

 same is true when a urine poor in normal constituents contains large 

 amounts of foreign bodies, such as albumin or sugar. 



As above stated, the percentage of solids in the urine generally decreases 

 with a greater elimination, and a very considerable excretion of urine 

 (polyuria) has therefore, as a rule, a lower specific gravity. An important 

 exception to this rule is observed in urine containing sugar (diabetes 

 mellitus), in which there is a copious excretion with a very high specific 

 gravity due to the sugar. In cases where very little urine is excreted 

 (oliguria), e.g., during profuse perspiration, in diarrhoea, and in fevers, 

 the specific gravity of the urine is as a rule very high; the percentage of 

 solids is also high and the urine has a dark color. Sometimes, as for 

 example, in certain cases of albuminuria, the urine may have a low specific 

 gravity notwithstanding the oliguria, and be poor in solids and light in 

 color. i 



In certain cases it is interesting to know the relation between the 

 carbon and the nitrogen, or the quotient C/N. This factor may vary 

 between 0.6 and 1 ; as a rule, it amounts on an average to 0.87, but changes 

 according to the nature of the food and is higher after a diet rich in carbo- 

 hydrates than after food rich in fat (PREGL, TANGL, LANGSTEIN and 

 STEINITZ). According to MAGNUS- ALSLEBEN it rises after body exer- 

 tion, but in healthy individuals the variation is independent of the 

 kind of food. In the urine analyses of BOUCHEZ 2 a variation between 

 0.62 and 0.90 was observed which showed no regular relation to the food. 



On account of the great variations which the composition of the urine 

 shows it is difficult and of little value to give a tabular review of the 

 composition of the urine. The following table contains only approximate 

 values and it must not be overlooked that the results are not given for 

 1000 parts of urine, but only approximate figures for the quantities 



1 Journ. Amer. Chem. Soc., 25. 



2 Pregl, Pfliiger's Arch., 75, which contains the earlier literature. Tangl, Arch. f. 

 (Anat. u.) Physiol., 1899, Suppl.; Langstein and Steinitz, Centralbl. f. Physiol., 19; 

 Magnus-Alsleben, Zeitschr. f. klin. Med., 68, Bouchez, footnote 1, page 767. 



