SULPHUKOUS ACID AND SULPHITES. 



839 



TABLE VIII. Urine determinations Relative amounts of nitrogen, sulphur, and 

 phosphoric acid excreted, expressed as percentages of amounts ingested, Series VII 

 Continued. 



SUMMARIES. 



CHANGES IN THE RELATIVE QUANTITIES OF SULPHUR COM- 

 POUNDS EXCRETED IN THE URINE. 



The fact that sulphur was administered both in the form of a pre- 

 servative and in the food presents a very interesting problem in 

 tracing its final elimination from the body. This point is also con- 

 sidered in the discussion of the sulphur balances. Since the kidneys 

 practically have the entire duty of eliminating the preservative, the 

 urine in this case is worthy of special study in regard to the sulphur 

 content. In Table XI are the data for the various sulphur, deter- 

 minations made on the urine, including total sulphur as S and as SO 3 , 

 and the following determinations as SO 3 : Total sulphates; neutral 

 sulphur (representing the sulphur which is held in organic combi- 

 nation and is not completely oxidized) which is the difference between 

 the total sulphur and total sulphates as SO 3 ; ethereal sulphates; 

 inorganic sulphates (total minus the ethereal sulphates), and the 

 ratio of the ethereal to the inorganic sulphates. In addition, neutral 

 sulphur, and total ethereal and inorganic sulphates are expressed in 

 percentage of the total sulphur eliminated. 



To determine whether any of the preservative was excreted as 

 sulphites or sulphurous acid the distillation method for the deter- 

 mination of sulphurous acid was used. a Volumetric determinations 

 of the iodin were useless, as small amounts were found on blank 

 determinations. The iodin was boiled off and the sulphates formed 

 precipitated by barium chlorid. By this method blank determina- 

 tions on normal urine gave 0.08 milligram of SO 2 in 200 cc of urine. 

 Determinations during the various preservative periods on 200 cc of 

 the urine never gave over 1 milligram, the average being 0.07. 



INDIVIDUAL DATA. 



It is seen in the case of No. 1 that there is an average daily increase 

 of 300 milligrams of total sulphur eliminated in the preservative 

 period and an average increase of 36 milligrams in the after period 



all. S. Dept. Agr., Bureau of Chemistry, Bui. 107, p. 187. 



