360 PHYSIOLOGICAL CHEMISTRY. 



both of which are found in acid urines at the same time. OTT 

 found that on an average 60$ of the total phosphoric acid was 

 double- and 40$ was simple-acid phosphate. The total quantity of 

 phosphoric acid is very variable and depends on the kind and the 

 quantity of food. The average amount of P 2 5 is in round num- 

 bers 2.5 grms., with a variation of 1-5 grms., per 24 hours. The 

 phosphoric acid of the urine originates to a small extent from the 

 burning of organic compounds, nuclein, protagon and lecithin, 

 within the organism. The greater part originates from the phos- 

 phates of the food, and the quantity of eliminated phosphoric acid 

 is greater when the food is rich in alkali phosphates in proportion 

 to the quantity of lime and magnesia phosphates. If the food con- 

 tains much lime and magnesia, large amounts of earthy phosphates 

 are eliminated by the excrements ; and even though the food con- 

 tains considerable amounts of phosphoric acid in these cases, the 

 quantity of phosphoric acid in the urine is small. Such a condition 

 is found in the herbivora, whose urine is habitually poor in phos- 

 phates. The extent of the elimination of phosphoric acid by the 

 urine depends not only upon the total quantity of phosphoric acid 

 in the food, but also upon the relative amounts of alkaline earths 

 and the alkali salts in the food. 



From the transformation of tissues rich in proteid or of phos- 

 phorized nerve-substance in the body we might perhaps expect an 

 equal relation between the nitrogen and the phosphoric acid in the 

 urine. Many investigations have been made upon this subject by 

 ZTJELZER, STRUBING, and EDLEFSSE^; but as all the conditions 

 which affect the elimination of phosphoric acid are not yet suffi- 

 ciently known, it is difficult to draw any definite conclusions from 

 the observations thus far made. 



Little is known in regard to the elimination of phosphoric acid 

 in disease. In febrile diseases the amount of phosphoric acid is 

 considerably decreased as compared with the urea (ZUELZER). In 

 diseases of the kidneys the activity of these organs in eliminating 

 the phosphates is considerably diminished (FLEISCHER). In men- 

 ingitis, on the contrary, a marked increase in the phosphates is 

 observed in the urine. TEISSIER has described a special form of 

 polyuria, in which abundant quantities of earthy phosphates, 

 10-20-30 grms. per 24 hours, were eliminated. This polyuria was 



