468 APPENDIX. 



2. Examine the resulting crystals with a microscope and test 

 their solubility in ammonia, caustic soda, and hydrochloric acid. 



3. Prove that the substance contains sulphur, as follows : place a 

 small amount in a test-tube, dissolve in caustic alkali, add a few 

 drops of acetate of lead solution, and boil ; note the brownish-black 

 color which results owing to the formation of sulphide of lead. 



4. Repeat the preceding experiment : (a) with normal urine ; 

 (6) with urine to which a solution of cystin has been added. 



5. Estimate the amount of neutral sulphur in the urine as de- 

 scribed on page 290. (Be careful with the sodium peroxide.) 



Exercise XXXVI. 1. Prepare a solution of glucose in water 

 (about 1 per cent.) or in urine, and perform : (a) Nylander's test ; 

 (b) Fehling's test ; (c) the fermentation test ; and (d) the phenyl- 

 hydrazin test, as described on pages 293 and 294. 



2. Determine the melting-point of : (a) phenyl-glucosazon ; to this 

 end, purify the crystals and dry them as described on page 295. 

 Prepare a capillary tube about 1 J inches long and with a lumen of 

 approximately 1 mm., seal one end, place some crystals of the osazon 

 in the interior ; fasten the tube with platinum wire to the bulb of a 

 thermometer registering about 250 C. ; suspend the thermometer in 

 concentrated sulphuric acid in a beaker ; heat gently and note the 

 temperature at which the crystals melt. In a similar manner prepare 

 the osazons of: (b) lactose, (c) laevulose, and (d) maltose, and deter- 

 mine the melting-points as described. 



3. Estimate the amount of glucose in solution : (a) with the 

 polarimeter ; (b) by the differential density method ; (c) by Knapp's 

 method ; and (d) by Fehling's method. (The solution of glucose 

 should stand twenty-four hours before being polarized.) 



Exercise XXXVII. 1. Prepare a dilute solution of arabinose 

 (0.1 per cent.) ; perform the orcin test as described by Bial (page 300). 



2. Test with Fehling's solution. 



3. Prepare the corresponding osazon and determine the melting- 

 point (see preceding Exercise). 



Exercise XXXVIII. 1. Procure some albuminous urine and 

 perform : (a) the nitric acid test ; (b) the boiling test ; (c) the potas- 

 sium ferrocyanide test (pages 302 and 303). 



2. Demonstrate the presence of two albumins in such urine, one 

 of which coagulates between 50 and 60 C., and the other between 

 65 and 75 C. ; note that the former is present in smaller amount. 

 Make the examination by hanging a thermometer registering 100 C. 

 in a wide test-tube about one-third full of urine ; immerse this well 

 in a large beaker of water ; heat very slowly. Prove that one of 

 the two albumins is serum-albumin and the other serum-globulin 

 (page 304). 



3. Estimate the amount of albumin : () gravi metrically ; (b) by 

 Esbach's method. 



4. Procure urine from a case of acute cystitis. Test for nucleo- 

 albumin as described on page 304. 



