26 THE JOURNAL OF PHARMACOLOGY. 



from the number of cc. of decinormal silver nitrate solution, originally 

 employed. The difference represents the number of cc. of decinormal silver 

 nitrate solution which were actually required to combine with the chlorine 

 present. From this the quantity of chlorine expressed as such, or as 

 sodium chloride, eliminated during 24 hours is calculated. 



N 

 I cc. of AgNOs V-S = 0.003537 gm. chlorine. 



^° = 0.005837 gm. sodium chloride. 



Example : To 10 cc. of urine 25 cc. of decinormal silver nitrate solution 

 were added ; 50 cc. of the filtrate (obtained as above) required for the 

 production of a permanent reddish tint, 2.5 cc. of the decinormal 

 potassium sulphocyanate solution ; 100 cc. (the entire filtrate) would, 

 therefore, have required 5 cc. As each cc. of the decinormal potassium 

 sulphocyanate solution is the exact equivalent of i cc. of the decinormal 

 silver nitrate solution, therefore, 5 cc. represent the number of cc, of deci- 

 normal silver nitrate solution which were added in excess. 25 — 5 = 20, 

 this number therefore represents the number of cc. of decinormal silver ni- 

 trate solution required to combine with all the chlorine in the sample. If 

 each cc. of the decinormal silver nitrate solution is the equivalent of 0.005837 

 gm. of sodium chloride, then 20 cc. will be the equivalent of 20 X 0.005837, 

 or . 1 16740 gm. of sodium chloride, or this quantity was present in 10 cc. of 

 urine. Now suppose 1200 cc. of urine were eliminated during 24 hours ; 



then, 



ro : .11674 *• ^200 : x = 14.0088, 



or 14.0088 grammes of sodium chloride were present in the urine passed 

 during 24 hours. 



It is of course not absolutely necessary to employ decinormal silver ni- 

 trate V.S. Any silver solution whose sodium chloride or chlorine equiv- 

 alent is known may be employed. The solution of potassium sulphocy- 

 anate also need not correspond cc. for cc. to the decinormal silver nitrate 

 solution. Its exact relation to this must, however, be known. 



Example : To the 50 cc. of filtrate (as above), containing 15 cc, of the 

 decinormal silver nitrate solution, it was found necessary to add 6 cc, of 

 potassium sulphocyanate solution, or 12 cc. to 100 cc. of filtrate. Accor- 

 ding to its titre, 9.6 cc. of this potassium sulphocyanate solution were the 

 equivalent of 10 cc. of the decinormal silver nitrate solution. Therefore, 

 12.5 cc. must be deducted from the 30 cc. of decinormal silver nitrate so- 

 lution originally employed, as follows : 



9.6 : 10 :: 12 : x = 12.5, 



30 — 12.5 = 17.5. 17.5 X 0.005837 = .1021 4- gm. or 1,021 % sodium 

 chloride in 10 cc. of the sample employed. 



2. The quantitative estimation of chlorine may be carried out after ash- 

 ing the sample of urine with sodium carbonate and sodium nitrate. In 



