74 LABORATORY WORK IN PHYSIOLOGICAL CHEMISTRY. 



cipitate should be protein-free. Test it. What is the dif- 

 ference between the two precipitates? What is another 

 method for the separation of albumins and globulins? 



(c) To 5 c.c. of the serum add 10 c.c. of 95 per cent alcohol. 



(d) " 5 " " " " at 30 C add anhydrous Na 2 S0 4 

 to saturation. 



(e) To 5 c.c. of the serum add a solution of uranium 

 acetate until no further precipitate is obtained. 



After the removal of the precipitates in experiments 

 (c), (d), and (e), test the nitrates for protein. 



SUGAR AND SODIUM CHLORIDE. 



Use the protein-free filtrate from experiment a (under 

 Proteins). 



(a) Test a few c.c. of the filtrate with Fehling's solution. 



(6) Allow a few c.c. to evaporate on a watch-glass over 

 the water-bath. Examine the glass under the microscope. 



(c) Test for chlorides. 



BLOOD PLASMA. 



(a) To a few c.c. of oxalated plasma add a few drops of 

 a 2 per cent CaCl 2 solution. What is the result? Why? 



(6) Dilute 2 c.c. of salted plasma with 10 volumes of 

 water. What happens? 



(c) Do the same to some serum. What is the difference, 

 and why?. 



(d) To 5 c.c. of the salt-plasma add an equal volume of 

 a saturated NaCl solution. What is the precipitate? 



FIBRIN. 



This substance is formed by the action of the fibrin fer- 

 ment upon the globulin, fibrinogen, which is present in all 

 the coagulable fluids of the body. 



