BLOOD. 201 



4. Sugar in Serum. Test a little of the filtrate from Experi- 

 ment 3 by Fehling's test. What do you conclude? 



5. Detection of Sodium Chloride. (a) Test a little of the 

 filtrate from Experiment 3 for chlorides, by the use of nitric acid 

 and argentic nitrate, (b) Evaporate 5 c.c. of the filtrate from 

 Experiment 3 in a watch glass on a water-bath. Examine the 

 crystals and compare them with those reproduced in Fig. 60, 

 page 200. 



6. Separation of Serum Globulin and Serum Albumin. Place 

 10 c.c. of blood serum in a small beaker and saturate with magne- 

 sium sulphate. What is this precipitate? Filter it off and acidify 

 the filtrate slightly with acetic acid. What is this second precipi- 

 tate? Filter this precipitate off and test the filtrate by the biuret 

 test. What do you conclude? 



III. Blood Plasma. 



1. Preparation of Oxalated Plasma. Allow arterial blood to 

 run into an equal volume of 0.2 per cent ammonium oxalate 

 solution. 



2. Preparation of Fibrinogen. To 25 c.c. of oxalated plasma 

 add an equal volume of saturated sodium chloride solution. Note 

 the precipitation of fibrinogen. Filter off the precipitate (reserve 

 the filtrate) and test it by a protein color test (see page 90). 



3. Effect of Calcium Salts. Place a small amount of oxalated 

 plasma in a test-tube and add a few drops of a 2 per cent calcium 

 chloride solution. What occurs? Explain it. 



4. Preparation of Salted Plasma. Allow arterial blood to run 

 into an equal volume of a saturated solution of sodium sulphate 

 or a 10 per cent solution of sodium chloride. Keep the mixture 

 in a cold place for about twenty- four hours. 



5. Effect of Dilution. Place a few drops of salted plasma in a 

 test-tube and dilute it with 10-15 volumes of water. What do you 

 observe? Explain it. 



6. Crystallization of Oxyhaemoglobin. Reichert's Method 

 Add to 5 c.c. of the blood of the clog, horse, guinea-pig, or rat, 



:fore or after laking, or defibrinating, from I to 5 per cent of 

 immonium oxalate in substance. Place a drop of this oxalated 

 >lood on a slide and examine under the microscope. The crystals 

 f oxyhsemoglobin will be seen to form at once near the margin 

 >f the drop, and in a few minutes the entire drop may be a solid 



lass of crystals. Compare the crystals with those shown in Figs. 

 ;o to 56, pages 1 86 to 189. 



