freshly teased tissues add an alkaline mixture of u-naphthol and 

 p-diamino benzene solutions in 0.7' ','< NaCl. Note the results. Ar- 

 range the tissues in the order of their actiritv in accelerating this 

 oxidation. 



97. Localization of iinloplicnol formation in blood corpuscles of 

 the fro(j. Prepare 4 cc. of a mixture of equal parts saturated solu- 

 tion of alpha naphthol in an alkaline NaCl solution (m/8 NaCl -)- 

 m/ioo Na L ,CO :; ). and i% di-methyl para-diamino benzene in 0.7% 

 NaCl. Add this mixture to a few drops of a suspension of frog's 

 blood corpuscles in a solution of m/8 NaCl + m/ioo K.,C,O 4 in a 

 watch-glass. Mount two or three drops of this mixture en a slide so 

 as to have several air bubbles under the cover. In the course of a 

 few minutes the indophenol will appear in the cells. 



In which cells does it appear first? Where is it chiefly localized 

 in the cell ? Is there any relation between the position of the air bub- 

 bles and the rate of formation of the oxidation product? 



98. O.vidation test for blood with (juaiac tincture. Apply a little 

 guaiac suspension containing hydrogen peroxide to a blood stain. 

 Note the result. Other dried animal tissues give a similar reaction. 



IV. SPECIAL CHARACTERISTICS OF ENZYME ACTION. 



99. Specificity of enzyme action. Collect saliva, dilute with four 

 volumes of water and filter. Place about 3 cc. in each of five test- 

 tubes. Then add : 



a. 5 cc. of starch paste. 



b. 5 cc. of 5^- cane sugar solution. 



c. One drop of olive oil -(- 5 cc. I '/( Na.CO.,. 



d. A shred of fibrin -f- 5 cc. of 0.2% HO. 



e. 5 cc. milk. 



Set tubes a to e ( inclusive ) in water bath at 40 for i hour, and then 

 test the tubes as f ollo\vs : 



Tube a, for starch and glucose. 



Tube b, for glucose. 



Tube c, for soap by emulsification. 



Tube d, for peptone. 



Tube e, note if coagulation occurs. 

 What do you conclude as to the action of ptyalin in the saliva? 



100. Reversibility of enzyme action. Many enzymes are reversi- 

 ble in their action, i. e. they can accelerate either decompositions or 

 syntheses of the substances on which they act, according to the con- 



