308 URINE. [CH. XII. 



378. Hay's test for bile salts. Sprinkle the surface of 

 some urine in a test-tube with flowers of sulphur. The particles 

 fall to the bottom of the tube if bile salts are present. (See Ex. 316.) 



379. Oliver's test for bile salts. Acidify the urine with 

 acetic acid and filter if necessary. To it add a clear i per cent, 

 solution of Witte's peptone, also acidified with acetic acid. A white 

 precipitate indicates bile salts. (Ex. 317.) 



6. Glucose. 



Glucose is not, strictly speaking, an abnormal con- 

 stituent of urine. The author was finally convinced of 

 this some years ago when working at a method for the 

 detection of small amounts of glucose in urine* (see Ex. 381). 

 Folinf confirmed this, using practically the same method. 

 Recently Benedict and Osterbergf have introduced a new 

 method for the estimation of glucose in normal urine (see 

 Ex. 407), and although it has only been applied to a few 

 individuals, the results obtained are of very great im- 

 portance, and will probably serve as the starting point for 

 a new attack on the problems of diabetes. According to 

 these observers about i gram, of non-nitrogenous reducing 

 substance is excreted per diem, of which about 55 per cent, 

 is not fermentable by yeast, and has not yet been identified. 

 The effect of diet is interesting. The excretion is increased 

 by carbohydrate intake, especially at breakfast. A 

 similar intake at mid-day, during normal muscular activity, 

 has a much smaller effect. For this reason a normal 

 individual may pass a urine shortly after breakfast which 

 might cause him to be rejected as a diabetic when examined 

 for life insurance. Such cases would probably Be passed as 

 normal if a sample of the mixed 24 hours' specimen were 

 examined. The effect of taking glucose varies with the 

 dose and also with the time of administration. Apparently 



* Cole, Lancet, 1913, ii., p. 859. 



f Folin, Journ. Biol. Chem., xxii., p. 327. 



J Benedict and Osterberg, Journ. Biol. Chem., xxxiv., p. 195. 



