766 URINE. 



FOLIN l has suggested a method for estimating the sulphate-sul- 

 phuric acid as well as the ethereal-sulphuric acid, and also the total 

 sulphur, which is somewhat different from the ordinary methods. 



Nitrates occur in small quantities in human urine (SCHONBEIN), and they 

 probably originate from the drinking-water and the food. According to WEYL 

 and CITRON, 2 the quantity of nitrates is smallest with a meat diet and greatest 

 with vegetable food. The average amount is about 42.5 milligrams per liter. 



Potassium and Sodium. The quantity of these bodies eliminated 

 by the urine by a healthy adult on a mixed diet is, according to SALKOW- 

 SKi, 3 3-4 grams K2O and 5-8 grams Na20, with an average of about 2-3 

 grams K2O and 4-6 grams Na2O. The proportion of K to Na is ordinarily 

 3:5. The quantity depends above all upon the food. In starvation 

 the urine may become richer in potassium than in sodium, which results 

 from the lack of common salt and the destruction of tissue rich in potas- 

 sium. The quantity of potassium may be relatively increased during 

 fever, while after the crisis the reverse is the case. 



The quantitative estimation of these bodies is made by the gravi- 

 metric methods as described in works on quantitative analysis. In 

 the ' determination of the total alkalies new methods have been devised 

 by PRIBRAM and GREGOR, and for the potassium alone a method by 



AUTENRIETH and BERNHEIM. 4 



Ammonia. Some ammonia is habitually found in human urine and 

 in that of carnivora. The quantity in human urine on a mixed diet is 

 an average of 0.7 gram, according to NEUBAUER. MAILLARD 5 found 

 higher values for soldiers, namely 1.11 grams. The ammonia nitrogen 

 relative to the total nitrogen is, on a mixed diet, 3.6-5.8 per cent. 



As above stated (page 685), on the formation of urea from ammonia, 

 this quantity may represent the small amount of ammonia which is 

 excluded from the synthesis to urea by being combined with acids formed 

 in excess by combustion and not united with the fixed alkalies. This 

 view is confirmed by the observation that the elimination of ammonia was 

 smaller on a vegetable diet and larger on a rich meat diet than on a mixed 

 diet. After abundant meat feeding BOUCHEZ found, for example, 1.35- 

 1.67 gram NH? in twenty-four hours. The relationship of the ammonia 

 elimination to the acid formation in the animal body corresponds also 

 to the unquestioned relation between the hydrochloric acid content of the 



1 Journ. of Biol. Chem., 1, and Amer. Journ. of Physiol., 13. 



8 Schonbein, Journ. f. prakt. Chem., 92; Weyl, Virchow's Arch., 96, with Citron, 

 ibid., 101. 



Ibid., S3. 



4 Pribram and Gregor, Zeitschr. f. analyt. Chem., 38; Autenreith and Bernheim, 

 Zeitschr. f. physiol. Chem., 37. 



6 Journ. de Physiol. et de Path., 10. 



