200 



PHYSIOLOGICAL CHEMISTRY. 



frog. Note that the filtrate from the ox blood is colored whereas 

 that from the frog blood is colorless. What deduction do you 

 make regarding the relative size of the erythrocytes in ox and 

 frog blood? Does either filtrate clot? Why? 



II. Blood Serum. 



1. Coagulation Temperature. Place 5 c.c. of undiluted serum 

 in a test-tube and determine its temperature of coagulation accord- 

 ing to the method described on page 100. Note the temperature at 

 which a cloudiness occurs as well as the temperature at which coag- 

 ulation is complete. 



2. Precipitation by Alcohol. To 5 c.c. of serum in a test-tube 

 add twice the amount of 95 per cent alcohol and thoroughly mix 

 by shaking. What is this precipitate? Make a confirmatory test. 

 Test the alcoholic filtrate for protein. Explain the result. 



3. Proteins of Blood Serum. Place about 20 c.c. of undiluted 

 serum in a small evaporating dish, heat to boiling and at the boiling- 



FIG. 60. 



e; 



SODIUM CHLORIDE. 



point acidify slightly with dilute acetic acid. Of what does this 

 coagulum consist? Filter off the coagulum (reserve the filtrate) 

 and test it as follows : 



(a) Millons Reaction. Make the test according to directions 

 given on page go. 



(b) Hopkins-Cole Reaction, Make the test according to direc- 

 tions given on page 101. 



