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XV. Contributions to the Chemistry of the Urine. On the Variations in the Alkaline 

 and Earthy Phosphates in the Healthy State, and on the Alkalescence of the Urine 

 from Fixed Alkalies. By Henry Bence Jones, M.A., Cantab., Fellow of the 

 College of Physicians. Communicated by S. Hunter Christie, Esq., Sec. R.S. 



Received January 23, — Read June 19, 1845. 



On the Variations of the Earthy and Alkaline Phosphates in a healthy state of Urine. 



JllAVING observed the occurrence of a great excess of earthy phosphates in the 

 urine in some cases of disease, and having made frequent examinations as to the 

 quantity present on successive days, I found so great a discrepancy, that it became 

 necessary before any further progress could be made to ascertain the variations in 

 the amount of earthy phosphates in the urine of a healthy man, and, if possible, to trace 

 the causes which determined the presence of an excess or deficiency of these salts in 

 the urine. At the same time it was thought desirable to note the variations which 

 the alkaline phosphates presented in the same water, and to see if they were influ- 

 enced by the same, or by different causes. 



A healthy man taking food twice daily, with moderate exercise for three hours, was 

 the subject of the following experiments. The method followed was to take the 

 specific gravity of the urine, if ever it was not strongly acid adding a drop or two of 

 hydrochloric acid. Then from a weighed quantity, usually about 1000 grains, to 

 precipitate the earthy phosphates by means of pure ammonia, to filter, wash with 

 ammoniacal water, and heat them to redness, adding at last a drop or two of nitric 

 acid. Thus the earthy phosphates were determined. 



The alkaline phosphates were estimated by taking usually about 500 grains of urine, 

 adding an excess of chloride of calcium and then pure ammonia ; by this means all 

 phosphoric acid was precipitated as phosphate of lime ; this was filtered, well- washed, 

 and heated to redness with nitric acid ; by deducting the previously determined earthy 

 phosphates, the difference was considered as alkaline phosphate*. 



Though neither the calculation nor the method were perfectly accurate, yet they 

 answered well for the purposes of comparison ; and in disease the short delay before a 

 result was arrived at which might determine the diagnosis, and sometimes the treat- 



* The formation of a small quantity of carbonate of ammonia and the precipitation of some sulphate of 

 lime, which even long washing cannot entirely remove, make the result too high. The equivalent of lime 

 being less than that of soda tends to reduce the error. It must be remembered that the phosphoric acid is pre- 

 cipitated in combination with three equivalents of lime. 



MDCCCXLV. 2 Y 



