SULPHUKOUS ACID AND SULPHITES. 827 



1:5.9 in the fore period to 1:6.2 in the 'preservative period and 

 increasing to 1 : 6.3 in the after period. 



In the case of No. 12 there is a gradual decline throughout the 

 observation in the ratio of phosphoric acid to nitrogen, falling from 

 1:6.2 in the fore period to 1:5.9 in the preservative period and to 

 1 : 5.3 in the after period. 



Comparing the summaries of Nos. 1 to 6, inclusive, with those of 

 Nos. 8 to 11, inclusive, it is seen that the ratio of the phosphoric 

 acid to nitrogen for Nos. 1 to 6 in the fore period is 1:5.8, in the 

 preservative period 1:5.9, and in the after period 1:5.8. 



This shows a slight tendency on the part of the preservative, 

 namely, sodium sulphite, either to increase the excretion of nitrogen 

 or to diminish the excretion of phosphorus in relation to each other. 

 In this case it is noticed that the quantities of nitrogen and of phos- 

 phorus excreted are both decreased somewhat. In the after period 

 the ratio is restored to the same magnitude as that in the fore period. 



In the summaries for Nos. 8 to 11, inclusive, the ratio of the phos- 

 phoric acid to nitrogen is 1:6.1 in the fore period, 1:6.0 in the pre- 

 servative period, and 1:6.3 in the after period. In this case the 

 opposite condition obtains from that noted in the preceding instance. 

 The administration of the sulphurous acid in the form of a free acid 

 or gas has apparently increased the excretion of phosphoric acid in 

 relation to the nitrogen excreted, since the ratio is less. 



The disturbances which have been caused by the administration of 

 the preservative between the relative excretion of nitrogen and 

 phosphoric acid are not of a sufficient magnitude to warrant any 

 certain conclusions. If the two summaries be considered together, 

 it is evident that there has been practically no disturbance of the 

 relation between the excretion of these two substances. Considering 

 the two summaries separately, it would appear that the administra- 

 tion of the sulphurous acid in the form of sulphites tends to decrease 

 the elimination of phosphoric acid in relation to nitrogen, while if 

 administered in the form of uncombined acid it tends to increase the 

 excretion of phosphoric acid in relation to nitrogen. This change, 

 however, is so minute that it may be said that very little influence is 

 exerted by the preservative upon the relative excretions of phosphoric 

 acid and nitrogen in the urine. 



The problem may also be looked at from a different point of view, 

 as illustrated in Table Vllf. In this table the ratios are based on 

 the amounts of nitrogen, sulphur, and phosphoric acid excreted in 

 the urine, expressed as percentage of amounts ingested, instead of 

 making the comparison between the actual amounts of these sub- 

 stances excreted. In the preservative period the calculation for 

 sulphur excreted is made on the sulphur exhibited in the food plus 

 the sulphur administered as a preservative. 



