26 URINE. 



In the investigation of the chemical process of respiration 

 in man or the lower animals, three quantities are to be 

 determined, viz., the discharge of CO 2 , the absorption of 

 oxygen, and the discharge of water. In the most complete 

 methods (e.g., that of Regnault and Reiset) all three are 

 determined. In Pettenkofer's method, the CO 2 and H 2 O 

 discharge only are determined ; but the method has the 

 advantage of being applicable to large animals and to man. 



URINE. 



The average daily discharge of urine of an adult male on 

 full diet is 1500 grammes, containing about 36 grammes of 

 urea, 07 gramme of uric acid, 16 grammes of sodic 

 chloride, and about 6 grammes of other inorganic salts, 

 besides colouring matter and other organic constituents. 

 Hence urine contains about 4*0 per cent, of solids, including 

 2-4 per cent, of urea. Its acidity is equal to that of a 0*2 

 per cent, solution of oxalic acid. 



The salts of the urine are, common salt, potassic chloride, 

 sodic, calcic, and magnesic phosphates ; and sodic and 

 potassic sulphates. The discharge of sodic chloride varies 

 with the store of chlorine in the body. It is markedly 

 diminished by abnormal transudation of blood plasma. 



The discharge of alkaline phosphates also varies with the 

 quantity stored in the blood plasma ; that of earthy phos- 

 phates with the disintegration of proteids of food. Hypo- 

 sulphites and sulphates occur in the urine as results of a 

 process of oxidation which has its seat in the kidneys, for 

 sulphates are met with only in traces in the blood or tissues. 

 Of the two alkaline bases about 8 grammes (reckoned as 

 potash and soda) are discharged daily, the soda constituting 

 a little more than half. In fever and all conditions attended 

 with increased disintegration of tissue or blood-corpuscles, 

 the proportion of potash is larger. If carbonates exist in 

 the urine they are derived from the oxidation of vegetable 

 acids used as food. 



