INORGANIC CONSTITUENTS OF THE TJKINE. 213 



Sulphates. There is very little to be said regarding the 

 sulphates, beyond the general statements concerning the in- 

 organic principles of the urine. The proportion of these 

 salts is here very much greater than in the blood, in which 

 there exists only about 0*28 of a part per thousand. Inas- 

 much as the proportion in the urine is from three to seven 

 parts per thousand, it seems probable that the kidneys elimi- 

 nate these principles as fast as they find their way into the 

 circulating fluid either from the food or from the tissues. 1 

 Like other principles derived in great part from the food, 

 the normal variations in the proportion of sulphates in the 

 urine are very great. It is unnecessary to consider in detail 

 the variations in the amount of sulphates discharged in the 

 urine, depending upon the ingestion of different salts or upon 

 diet, for all the recorded observations have been followed 

 by the same results, and show that the ingestion of sulphates 

 in quantity is followed by a corresponding increase in the 

 proportion eliminated. Numerous experiments on this point 

 have been made by Yogel and others. 1 



Thudichum estimates the daily excretion of sulphuric 

 acid at. from twenty-three to thirty-eight grains. 3 Assum- 

 ing, with Eobin, that the sulphates consist of about equal 

 parts of sulphate of potassa and sulphate of soda, with traces 

 of sulphate of lime, 4 the quantity of salts would be from 22*5 

 to 37*5 grains of sulphate of potassa and an equal quantity 

 of sulphate of soda. 



Phosphates. The urine contains phosphates in a variety 

 of forms ; but inasmuch as it is not known that any one of 

 the different combinations possesses peculiar relations to the 

 process of disassirnilation, as distinguished from the other 

 phosphates, the phosphatic salts may be considered together. 



1 ROBIN, Lemons sur les humeurs, Paris, 1867, p. 663. 



2 XEUBAUER AXD VOGEL, op. cit, p. 404. 



3 THUDICHUM, A Treatise on the Pathology of the Urine, London, 1858, p. 416. 



4 ROBIN, loc. cit. 



