80 CHEMICAL PHYSIOLOGY. 



every 1000 parts" i.e., the number of grammes in 1000 cc. 

 (331 oz .) 



Example. Suppose a patient to pass 1200 cc. of urine in 

 twenty-four hours, and the specific gravity to be 1022, then 



22 x 2-33 = 51-26 grms. in 1000 cc. 

 To ascertain the amount in 1200 cc. 



1000 : 1200 : : 51-26 : a: = ^ = 61-51 grms. 



This formula is purely empirical, and is not applicable where 

 the variations are very marked, as in saccharine diabetes and 

 some cases of Bright's disease, where there is a great diminution 

 of urea. 



The normal quantity of solids, or the total solids sometimes 

 spoken of as " solid urine" is about 70 grms. in twenty-four 

 hours i.e., 1000 to 1050 grains. Parkes gives an average of 

 945 grains per day for an average adult male between twenty 

 and forty years of age. The latter estimate gives about 20 grains 

 of solids per fluid ounce of urine, or about 4 per cent, of solids. 



6. The Odour is "peculiar" and "characteristic," somewhat 

 aromatic in health. Certain medicinal and other substances 

 influence it turpentine (violets); cubebs, copaiba, and sandal 

 wood oil give a characteristic odour, and so do asparagus, 

 valerian, assafsetida, garlic, &c. In disease, note the ammoniacal 

 odour of putrid urine and the so-called " sweet " odour in saccha- 

 rine diabetes. 



7. The Reaction. Normal. Slightly acid, it turns blue litmus- 

 paper slightly red, and does not affect red litmus-paper. The 

 acidity is chiefly due to acid sodium phosphate (NaH 2 PO 4 ), acid 

 urates, and very slightly to free acids lactic, acetic, oxalic, &c. 

 A neutral urine does not alter either blue or red litmus paper. 

 A very acid urine turns blue litmus paper very red. Sometimes 

 violet litmus paper is used; it becomes red in acid urine and 

 blue in alkaline. 



(a.) Take two pieces of neutral litmus-paper, put a drop 

 of water on the one, and a drop of urine on the other, and 

 observe the effects. 



