88 HANDBOOK FOE BIO-CHEMICAL LABORATORY. 



water. This mixture should stand 2 months. For use mix 

 1 part of this solution with 3 parts water and filter. 



PA YY'S Reagent (Albumin). This is a practical dry reagent 

 for albumin. It consists of small disks or plates of citric acid 

 and sodium ferrocyanide. 



PAVY'S Solution (Glucose). Mix 120 c.c. of the ordinary 

 Fehling's solution with 300 c.c. of strong ammonia (sp. gr. 

 0.88) and with 400 c.c. more of caustic soda solution of sp. gr. 

 1.14. Now dilute to 1000 c.c. with water. One hundred c.c. 

 of this solution is reduced by glucose to the same extent as 

 10 c.c. of the ordinary Fehling's solution. This solution 

 becomes decolorized by boiling with glucose solution. 



PENZOLDT'S Test (Glucose). Dissolve 1 part diazobenzo-sul- 

 phonic acid in 60 parts of water, and to facilitate solution add 

 1 or 2 drops caustic potash. 



In applying this tejst make some of the solution to be 

 tested strongly alkaline, and then add an equal volume of the 

 above solution of diazobenzol sulphonic acid. It is advisable 

 to do the same with a solution free from sugar. On allowing 

 to stand the mixture becomes yellowish red or light claret 

 red, then darker, and in the presence of considerable glucose 

 it becomes dark red and opaque. The red color has a bluish 

 shade. 



PENZOLDT'S Test (Acetone). A warm saturated solution of 

 orthonitrobenzaldehyde is treated with the liquid to be tested 

 for acetone and then made alkaline with caustic soda. In the 

 presence of acetone the liquid first becomes yellow, then green, 

 and lastly indigo separates, and this may be dissolved with a 

 blue color by shaking with chloroform. 



