172 PHYSIOLOGICAL CHEMISTRY 



amounts depend much on the quantity of each present in the 

 food. In the case of calcium and magnesium much may be lost 

 in the feces. About 1 gram a day of the phosphates of these two 

 metals is found in the urine. Two to 4 or 5 grams each of 

 sodium and potassium may be excreted daily. 



Pathological Constituents of the Urine 



The most frequent pathological constituents of the urine are 

 proteins, carbohydrates, acetone bodies, casts, bacteria, etc. The 

 study of pathological urine lies properly in the field of 

 pathology. A short review of the kinds of the above substances 

 occurring most frequently in pathological urine has been in- 

 cluded in the laboratory chapter on the urine, together with the 

 most important or convenient methods for detecting and estimat- 

 ing them. Certain anomalies of metabolism leading to the ap- 

 pearance of these substances in urine will be discussed in the 

 chapter on metabolism. 



