THE INORGANIC CONSTITUENTS OF THE URINE. 491 



a reddish tint. Every cubic centimeter of silver-solution used corresponds to 10 

 mg. of sodium chlorid, or 0.00607 gram of chlorin. 



Phosphoric acid, about 2 grams daily, occurs in the form of mono- 

 potassium and monosodium phosphate, and acid potassium and mag- 

 nesium phosphate. It is present in larger amount after the ingestion of 

 animal than of vegetable food. Its amount increases from the mid- 

 day meal till evening, and it then declines in the night until the next 

 morning. It is increased by muscular activity. It is derived in largest 

 part from the alkaline and earthy phosphates of the food; and it is in 

 part a metabolic product of lecithin and nuclein. 



In the presence of fever, the increased elimination of potassium phosphate is 

 indicative of consumption of blood and muscle. When abnormal destruction of 

 blood takes place suddenly in the body, the phosphoric acid, together with the 

 urea, is greatly increased. In the state of hunger, the phosphoric acid is derived 

 principally from the breaking down of the bones, which contain thirty times as 

 much as the muscles. Also in the presence of cerebral meningitis, softening of 

 the bones, diabetes and oxaluria, the elimination of phosphorus is said to be in- 

 creased; likewise, after administration of lactic acid, morphin, chloral, or 

 chloroform. It is diminished during pregnancy, on account of the formation of 

 bone in the fetus. It is diminished also in consequence of the ingestion of 

 ether and alcohol, and likewise of inflammation of the kidney. 



Qualitative Estimation. Potassium hydrate is added to urine in a test-tube, 

 and heat is applied. The earthy phosphates are thus precipitated in a cloud, 

 while the alkaline phosphates remain in solution. For qualitative estimation, 

 there are necessary a titrated solution of uranic acetate, of which i cu. cm. unites 

 with exactly 0.005 gram of phosphoric acid. To 50 cu. cm. of urine are added 

 5 cu. cm. of a solution of sodium acetate containing 100 grams of the latter salt 

 and 100 cu. cm. of strong acetic acid diluted to i liter with water; and the mixture 

 is heated. The titrating solution is permitted to flow with stirring so long as 

 precipitation is apparent. As soon as free uranium oxid is present in the fluid, 

 one drop of the mixture, to which a solution of potassium ferrocyanid is added 

 upon a porcelain plate, yields a brownish-red reaction of uranium ferrocyanid. 



In addition to phosphoric acid, phosphorus occurs in the urine in an incom- 

 pletely oxidized form, namely as glycerin-phosphoric 'acid, about 0.05 gram 

 daily, in larger amount in the presence of nervous diseases and after chloroform- 

 narcosis. 



Sulphuric acid is united in part with alkaline metals, in part with 

 indol, phenol, skatol, and pyrocatechin, in the form of aromatic ethe- 

 real sulphates, both in the proportion of i to 0.1045 on the average. 

 All factors that favor the formation of indol, phenol, skatol, or pyro- 

 catechin increase the conjugate ethereal sulphates. The total amount 

 of sulphuric acid eliminated is from 2.5 to 3.5 grams daily. It is in- 

 creased after the ingestion of sulphur. The sulphuric acid is derived 

 principally from the decomposition of albuminates. It is increased 

 by muscular activity; and, therefore, its amount is always parallel to 

 that of the urea eliminated. The amount of alkaline sulphates ad- 

 ministered with the food is, as a rule, exceedingly small. 



Increased excretion of sulphuric acid in febrile urine indicates increased 

 tissue-metabolism in the body. In the presence of inflammation of the kidney 

 a diminution has been observed, in cases of eczema a marked increase in the 

 amount of sulphuric acid in the urine. In rabbits, but not in carnivora and 

 human beings, administration of taurin, which contains sulphur, causes the pres- 

 ence of an increased amount of sulphuric acid in the urine. According to Ziilzer, 

 the relative amount of sulphuric acid in the urine is small when the secretion 

 of bile in the intestine is large. 



The qualitative demonstration is made by addition of barium chlorid to the 

 urine, which yields a fine, white, insoluble precipitate of barium sulphate. 



For quantitative estimation, 50 cu. cm. of urine are strongly acidulated with 

 acetic acid and an equal volume of water and barium chlorid is added. After 



