METABOLISM 



625 



eliminated by way of the feces and a little less than half of the magne- 

 sium. From 20-30 per cent of the phosphorus ingested is usually found 

 in the feces. 



Experiments. (a) Ingest for a period of three days an ordinary mixed diet 

 without added salt and containing no milk. Separate the feces for the period (see 

 page 620) and retain a portion of the well-mixed feces for analysis. 



(b) Proceed as above with the exception that there is added to the mixed diet 

 10 grams of common salt and a quart of milk (containing about 1.6 grams of CaO, 

 0.2 gram MgO, 1.4 grams of chloride expressed as sodium chloride, and 2.2 

 grams P2O5). Mix feces well and reserve part for analysis. 



Ash 10 gram samples of the feces from the above diets. Dissolve with the aid 

 of a little dilute nitric acid, filter and make up to 100 c.c. Determine in aliquot 

 portions of this solution: (i) Chlorides by Volhard method. (2) Calcium and 

 magnesium by McCrudden's method. (3) Phosphorus by uranium titration. 

 (For details of analytical methods see Chapter XXVII.) Calculate the percent- 

 ages of the added Ca, Mg, P, and Cl which are recovered from the feces. 



For a more detailed study of chloride excretion combine this experiment and 

 Experiment 21 (see Experiment 20). 



IV. METABOLISM PROCEDURES INVOLVING THE 

 MANIPULATION OF BOTH URINE AND FECES 



41. Preparation of a Metabolic Balance. This test entails the 

 analysis of the food ingested and of the urine and feces excreted, i.e., 

 a study of the income and outgo. Proceed as follows: 



Select a diet which is simple, i.e., consists of few constituents, and which 

 lends itself readily to accurate chemical analysis. A good type of diet for ordi- 

 nary metabolism experiments of this sort consists of crackers (graham or soda), 



BALANCE OF CALCIUM, MAGNESIUM, PHOSPHORUS, SULPHUR, AND 

 NITROGEN IN ACROMEGALY 



40 



