216 



E. M. WiDDOwsoN AND R. A. McCance 



by the present series of adults was higher than that of the 

 newborn infants, the value for adults shown in Fig. 6 (70-80 

 per cent) has been taken from Gamble (1942). Phosphates 

 accounted for a very small fraction of the titratable acidity of 



m-inole/kg./24 h. 

 lO • 



0-8 

 06 

 0-4 

 02 

 O 



i 



--Adult 



O- 24-7- I 

 24hL 48h. 8 day year 



Fig. 5. The excretion of titratable 

 acid. 



the infant's urine, which is due to the fact, already mentioned, 

 that the urine of breastfed infants contains so little phosphate 

 at this time of life. 



Investigations are being made on the organic acids in the 



Adult 



^^^^^^ 



Infant 



Phosphate 



Organic acids 



j Phosphate 



Organic acids 



lO 20 30 40 50 60 70 80 

 Percentage of titratable acidity 



90 ICO 



Fig. 6. The proportion of titratable acid due to phosphates and 

 organic acids in the urine (pH 5 • 5-6 • 0) of adults and infants. 



urine during the first week of life. Citric acid is one of the 

 major constituents, and on the seventh day the breastfed 

 babies were found to be excreting 33 mg. citrate/kg. body 

 weight/24 hours (Stanier, personal communication). This 



