100 HANDBOOK FOB BIO-CHEMICAL LABORATORY. 



VITA LLI'S Test (Bile Pigments.) Treat the solution with 

 a few drops of a solution of potassium nitrite and then some 

 dilute sulphuric acid, when a beautiful green color will be 

 obtained. This green color changes to yellow after a time, 

 but first turns red or blue. 



WEBER'S Test (Indican in Urine). Treat 30 c.c. of the 

 urine with an equal volume hydrochloric acid and 1-3 drops 

 dilute nitric acid and heat to boiling. The solution becomes 

 dark, and if shaken with ether, when cold, the ether will be 

 colored red to violet, while a blue foam is observed on the top 

 of the ether. 



WEIDEL'S Reaction (Xantliiri). A little of the substance 

 is dissolved in fresh chlorine water containing some nitric 

 acid and evaporated on the water-bath to dryness. On expos- 

 ing the white or yellowish residue to the vapors of ammonia, 

 under a bell- jar, a red or purple violet color is produced. 



WENDKR'S Test (Glucose). Dissolve 1 part commercial 

 methylene blue in 3000 parts distilled water. On making this 

 solution alkaline with caustic potash and heating with a 

 glucose solution the blue color disappears and the solution 

 becomes decolorized. 



WETZEL'S Test (CO in Blood). Dilute the blood with 4 

 vols. water and treat with 3 vols. of a \<f> tannic acid solution. 

 In the presence of carbon monoxide the blood becomes car- 

 mine red, while normal blood gradually becomes gray. 



WEYL'S Reaction (Great in in). Add a few drops of a 

 freshly prepared solution of sodium nitro-prnsside to the 

 solution of creatinin and then a few drops of caustic soda. A 

 ruby-red liquid is obtained, which quickly turns yellow again. 

 The solution of creatinin zinc chloride may also be used. 



