BLOOD. 73 



(d) Add a few drops of bile, chloroform, and ether to 

 successive portions of 5 c.c. of blood. 



(e) To 5 c.c. of blood add 1 c.c. of hydrogen peroxide. 

 To what is the frothing due? 



(/) To about 10 c.c. of water add a few drops of blood 

 and enough freshly prepared tincture of guaiacum to cause 

 a slight turbidity. Then add to the mixture a few c.c. of 

 hydrogen peroxide. Explain the effects produced. 



(g ) Add 10-12 drops of a saturated glacial acetic acid solu- 

 tion of benzidine to 2-3 c.c. of 3% hydrogen peroxide. Mix and 

 to this add 2 or 3 drops of very dilute blood. Note change 

 in color. Try the same reaction using dilute blood which 

 has previously been boiled and then cooled. 



BLOOD SERUM. 



Blood serum presents a clear yellow liquid with a specific 

 gravity of 1.027-1.032. It consists of a watery solution of 

 serum albumins, globulins, enzymes, dextrose, fats, fibrin 

 ferment, inorganic salts, and a yellow coloring matter belong- 

 ing to the class of luteins or lipochromes. In addition it 

 holds in solution traces of nearly every soluble substance 

 which has been found in the body tissues. Of the 8-9 per 

 cent of total solids in the serum, 7 per cent is made up of the 

 proteins. NaCl is present to the extent of about 65 per 

 cent of the inorganic salts. 



PROTEINS. 



(a) Heat about 25-30 c.c. of serum to boiling with the 

 addition of a drop or two of acetic acid. Filter and test 

 filtrate and precipitate for protein (Millon's and biuret 

 reactions). Retain the filtrate. 



(6) Saturate 15 c.c. of the serum with MgS0 4 . Remove 

 the precipitate by filtration, and to the filtrate add two 

 drops of acetic acid. The filtrate from this second pre- 



