URINE 565 



The condition of cystinuria has been already explained 

 (p. 556), as has also the occurrence of alkaptonuria (p. 555). 



3. Phosphorus-containing Bodies. 



In herbivorous animals phosphates are practically absent 

 from the urine. They are excreted from the mucous membrane 

 of the bowel. Hence, in the horse, crystals of triple phosphates 

 are found in the faeces, not in the urine. 



In carnivores the phosphorus in the urine is derived partly 

 from phosphates taken in the food, and partly from the nucleins 

 of the food and tissues and from the bones. 



(a) Normally the phosphorus is fully oxidised to PoOj, 

 which is linked to alkalies and earths, and excreted in the 

 urine. The most important phosphate is the phosphate of soda, 

 NaH.PO^, which is the chief factor in causing the acidity 

 of the urine. When the urine becomes ammoniacal, triple 

 phosphate is formed (p. 559). 



(6) It is probable that a small quantity of the phosphorus 

 is excreted in organic compounds, such as glycero-phosphates ; 

 but so far these have not been fully investigated. 



4. Chlorine Compounds. 



Sodium chloride is the chief salt of the urine. It is entirely 

 derived from the salt taken in the food, and its amount varies 

 with the amount ingested. From 10 to 15 grms. are usually 

 excreted per diem in a person on a normal diet. 



In starvation, to a certain extent, and very markedly in 

 fever, the tissues of the body have a great power of holding on 

 to the chlorine, and the chlorides may almost disappear from 

 the urine. 



5. Inorganic Bases of the Urine. 



Sodium, potassium, calcium, and magnesium occur in the 

 urine in amounts varying with the amounts taken in the food. 

 On a flesh diet and in starvation potassium is in excess of the 

 others. Calcium and magnesium are present in much smaller 

 quantities. In herbivora potassium is the chief salt, and in the 

 horse calcium is also abundant. 



