28 



patients suffering from all kinds^of J^evers. In testing for hip- 

 purie acid the fresh urine shonld'l3e used; if stale, benzoic acid is 

 likely to be obtained instead. 



Test. Saturate the fresh urine with lime water, which 

 transforms the' hippuric acid into a salt of lime, the fluid 

 is then filtered, evaporated to a syrupy consistency and 

 excess of hydrochloric acid added, when hippuric acid 

 crystallizes out on standing. The horse urine is to be 

 evaporated in the hood. 



Creatinin (C4H7N3O). This substance was discovered in 

 the urine by Liebig. It is easily produced from creatin, a sub- 

 stance normally existing in plain and striated muscular tissue. 

 Creatinin occurs constantly in normal human urine, the amount 

 varying according to Voit, from 0.5 to 4.9 grams per day accord- 

 ing to the quantity of proteids eaten. It is said not to be dimin- 

 ished by fasting. 



Pathologically it is increased in 

 typhoid fever; intermittent fever; 

 pneumonia; tetanus. It is de- 

 creased during convalescence from 

 the above diseases ; and likewise 

 in anemia ; chlorosis ; muscular 

 atrophy ; tuberculosis ; paralysis, 

 etc. 



Test. Add a little caustic soda 

 to the urine and then a few drops 

 of freshly prepared 1% sodium 

 nitro-prusside. A ruby red color 

 develops. Boil, the color fades. "While boiling, add glacial 

 acetic acid, the color changes to blue. The above is a modi- 

 fication of Weyl's test. Acetone, if present, also gives the 

 red reaction. 



Perform the above test on both urines. 

 Caution. Creatinin reduces copper oxide and may 

 be taken for small quantities of sugar. 

 Mucus. Mucus in the urine is not visible, but causes 

 cloudiness sometimes by entangling epithelial cells, urates, oxalate 

 of lime and other crystals in various amounts. 



Add to the urine a little acetic or citric acid and, in 



