394 



REACTION OF URINE. 



4. Consistence. Normal urine, like water, is a freely mobile fluid. 



Large quantities of sugar, albumin, or mucus make it less mobile ; while the so-called chylous 

 urine of warm climates may be like a white jelly. 



5. The taste is a saline bitter, the odour is characteristic and aromatic. 

 Ammoniacal urine has the odour of ammonia. Turpentine taken internally gives rise to the 



odour of violets, copaiba and cubebs a strongly aromatic, and asparagus an unpleasant odour. 

 Valerian, assafcetida, and castoreum [but not camphor] also produce a characteristic odour. 

 [The odour of diabetic urine is described as "sweet.' ] 



6. The reaction of normal urine is acid, owing to the presence of acid salts, 

 chiefly acid sodic phosphate, which seems to be derived from basic sodic phosphate, 

 owing to the uric acid, hippuric acid, sulphuric acid, and C0 2 taking to themselves 

 part of the soda, so that the phosphoric acid forms an acid salt. After a diet of 

 flesh, acid potassic phosphate is the cause of the acidity. That the urine contains 

 no free acid is proved by the fact that it gives no precipitate with sodic hypo- 

 sulphite {v. Voit, Huppert). 



The acid reaction is increased after the use of acids, e.g., hydrochloric and phosphoric, also 

 by ammoniacal salts, which are changed within the body into nitric acid ; lastly, after 

 prolonged muscular exertion. The morning urine is strongly acid. 



The urine becomes less acid or alkaline (1) By the use of caustic alkalies, alkaline 

 carbonates, or alkaline salts of the vegetable acids, the last being oxidised within the body 

 into carbonates. (2) By the presence of calcic, or magnesic carbonate. (3) By admixture 

 with alkaline blood, or pus. (4) By removing the gastric juice through a gastric fistula (p. 246, 

 Maly) ; further, from one to three hours after a meal. [The reaction of urine passed during 

 digestion may be neutral, or even alkaline. This is due either to the formation of acid in the 

 stomach (Bence Jones), or to a fixed alkali derived from the basic alkaline phosphates taken 

 with the food ( W. Roberts).] (5) The urine is rarely alkaline in anaemia, owing to a deficiency 

 of phosphoric and sulphuric acids. [(6) The nature of the food vegetable food makes it 

 alkaline. (7) By profuse sweating. (8) By absorption of alkaline transudations (blood, 

 serum).] 



[Method. The reaction of urine is tested by means of litmus paper. Normal urine turns 

 blue litmus paper red, and does not affect red litmus. An alkaline urine makes red litmus 

 paper blue, while a neutral urine does not alter either blue or red litmus paper.] Sometimes 

 violet litmus paper is used, which becomes red in acid, and blue in alkaline urine. 



Estimation of the Acidity. This is done by determining the amount of caustic soda 

 necessary to produce a neutral reaction in 100 c.c. of urine. A soda solution, containing 0*0031 

 grm. of soda in each c.c. is used ; 1 c.c. of this solution exactly neutralises 0*0063 grrn. oxalic 

 acid. To the 100 c.c. of urine in a beaker, soda solution is added, drop by drop, from a 

 graduated burette (tig. 251), until violet litmus paper becomes neither red nor blue. The 

 number of c.c. of soda solution is now read off on the burette, and as each c.c. corresponds to 



