METABOLISM 



583 



(either organic or inorganic) or acid salts, e.g., sodium dihydrogen phos- 

 phate will increase the hydrogen ion concentration of the urine. The 

 alkalis are much more effective in producing changes in reaction than 

 are the acids. The influence of ingested alkali (sodium bicarbonate) is 

 shown in the foregoing table containing data submitted by Henderson 

 and Palmer. 1 



Blatherwick 2 reports a decrease in ammonia nitrogen output from 

 0.256 gram to 0.072 gram, and an accompanying decreased acidity 

 under the influence of bicarbonate ingestion (25 grams in two days). 



The influence of ingested acid (benzoic) is shown in the following 

 data reported by Blatherwick. 2 



INFLUENCE OF BENZOIC ACID INGESTION 3 



(For further discussion of dietary alterations of urine reaction see 

 preceding experiment.) 



Experiments. (a) Influence of Alkali. Ingest a uniform diet consisting of 

 milk, crackers, butter, peanut butter and distilled water for a period of two 

 days. During the next two days take the same diet and ingest 24 grams of 

 sodium bicarbonate between meals (12 in A. M. and 12 in P. M.). Collect the 

 urine in 24-hour periods and analyze it for titratable acidity, H ion concentra- 

 tion and ammonia. Compare your results with those shown in table on 

 page 582. 



If desired the bicarbonate may be given in one dose of 8-12 grams and the 

 urine collected in hourly specimens for the next five hours and each specimen 

 analyzed. Data from such experiments are shown in table on page 582 . 



(b) Influence of Acid. Proceed as above except that i gram of benzoic acid 

 (in capsule) is ingested before each meal of the experimental period. 



The experiment may also be varied by ingesting 10 grams of sodium dihydro- 

 gen phosphate early in the day and collecting the urine in hourly fractions or in 

 one 24-hour sample. 



1 Henderson and Palmer: Jour. Biol. Chem., 14, 81, 1913. 

 2 See p. 581. 



3 One gram of benzoic acid in a capsule before each meal. Basal diet No. i described on 

 page 582 was used. 



