500 VICTOR C. MYERS 



this sugar roughly half is fermentable. The 24 hr. elimination may vary 

 from 0.5 to 1.5 grams, but from a large series of analyses made by Croll 

 on hospital cases the daily average would appear to be about 0.7 gram. 

 Unless the carbohydrate tolerance is definitely disturbed, larger amounts 

 do not appear to be excreted. Even in hyperthyroidism comparatively 

 normal values are found. 



Inorganic Constituents 



. 



The inorganic constituents of the urine are chiefly the sodium, potas- 

 sium, calcium, magnesium and ammonium salts of hydrochloric, phos- 

 phoric and sulphuric acids. The salts of sodium and potassium are elimi- 

 nated almost exclusively in the urine, but, as pointed out in the section 

 on feces, much more calcium and magnesium are eliminated by the intes- 

 tine than by the kidneys, these elements being largely in combination 

 with phosphoric acid. The average inorganic solid elimination in the 

 urine amounts to about 20 grams daily, sodium chlorid ordinarily con- 

 tributing considerably more than half of the total. The average elimina- 

 tion of these different constituents for the human adult may be given as 

 follows : 



Grams 



Sodium as Na 2 O c , 6.0 



Potassium as K 2 3.0 



Calcium as CaO 0.3 



Magnesium as MgO < . 0.2 



Ammonium as NH 3 , , 0.6 



Iron as Fe. . . o . . . . 0.003 



Chlorids as Cl , 7.0 



Phosphates as P 2 O 5 . 2.5 



Sulphates as SO 3 . . 2.0 



Long and Gephart have made fairly complete mineral analyses on 

 the composite urines of six healthy adults. They found that they could 

 obtain an almost exact balance between acids and bases, if they assumed 

 that four-fifths of the phosphoric acid was held as dihydrogen phosphate 

 and one-fifth as monohydrogen phosphate. On this basis they suggested 

 the arbitrary salt combinations given in tabular form on the next page. 



Chlorids. The amount of chlorids, chiefly sodium chlorid, excreted 

 per day is dependent upon the food chlorids. The elimination is quite 

 variable but ordinarily falls between 10 and 15 grams. Some people 

 ingest very large amounts of salt with their food. This" salt is absorbed 

 and passes rapidly through the kidneys into the urine. In starvation the 

 sodium chlorid excretion is reduced to a minimum. The same conditions 



