Development of Acid-Base Control 



213 



Fig. 2 shows the percentage of the surplus anions excreted 

 with ammonia. For this it is possible to give a figure for urine 

 which was formed in utero and passed at the moment of birth 

 and which had a pH of over 6. It will be observed that, 

 although the pH of the urine passed at birth was higher than 

 that of the urine passed afterwards, the percentage of the 

 surplus anions excreted with ammonia was also very high 

 before birth, and of the order to be expected in adults with 



% 



80 

 70 

 60 

 SO 

 40 

 30 

 20 

 lO 



I 



i 



i 



•Adult 



Before O- 24- 7- I 

 birth 24 K 48h. 8 day year 



Fig. 2. Percentage of the surplus 

 anions excreted as ammonium salts. 



very acid urines after taking large doses of ammonium chloride 

 for some days. The percentage of the surplus anions excreted 

 with ammonia in the first 48 hours and on the seventh day of 

 life has also tended in our series to be higher than that in the 

 urine passed by adults. This is probably because the babies' 

 urine contained so little phosphate, and consequently the 

 titratable acidity was low in relation to the total amount of 

 surplus anions to be excreted. It was not because the ability 

 of the newborn kidney to produce ammonia was greater than 

 that of an adult, for all the evidence is against this. Work 



