CARBOHYDRATES. 47 



enzyme inulase it yields the monosaccharide Isevulose which readily 

 reduces Fehling's solution. The ordinary amylolytic enzymes occur- 

 ring in the animal body do not digest inulin. 



EXPERIMENTS ON INULIN. 



1. Solubility. Try the solubility of inulin powder in each of 

 the ordinary solvents. If uncertain regarding the solubility in any 

 reagent, filter and neutralize the filtrate if it is alkaline in reaction. 

 Add a drop of concentrated hydrochloric acid to the filtrate and 

 boil it for one minute. Render the solution neutral or slightly 

 alkaline with solid potassium hydroxide and try Fehling's test. 

 What is the significance of a positive Fehling's test in this connection ? 



2. Iodine Test. (a) Place 2-3 c.c. of the inulin solution in a 

 test-tube and add a drop of dilute iodine solution. What, do you 

 observe ? 



(b) Place a small amount of inulin powder in one of the depres- 

 sions of a test-tablet and add a drop of dilute iodine solution. Is 

 the effect any different from that observed above? 



3. Molisch's Reaction. Repeat this test according to directions 

 given under Dextrose, 2, page 23. 



4. Fehling's Test. Make this test on the inulin solution accord- 

 ing to the instructions given under Dextrose, page 27. Is there any 

 reduction P 1 



5. Hydrolysis of Inulin. Place 5 c.c. of inulin solution in a 

 test-tube, add a drop of concentrated hydrochloric acid and boil 

 it for one minute. Now cool the solution, neutralize it with con- 

 centrated KOH and test the reducing action of i c.c. of the solution 

 upon i c.c. of diluted (1:4) Fehling's solution. Explain the result. 2 



GLYCOGEN, (C 6 H 10 5 )x. 



(For discussion and experiments see Muscular Tissue, Chapter 

 XV.) 



1 See the discussion of the properties of inulin, page 46. 



~ If the inulin solution gave a positive Fehling test in the last experiment it 

 will be necessary to check the hydrolysis experiment as follows: To 5 c.c. of 

 the inulin solution in a test-tube add one drop of concentrated hydrochloric 

 acid, neutralize with concentrated KOH solution and test the reducing action 

 of i c.c. of the resulting solution upon i c.c. of diluted (1:4) Fehling's solu- 

 tion. This will show the normal reducing power of the inulin solution. In 

 case the inulin was hydrolyzed, the Fehling's test in the hydrolysis experiment 

 should show a more pronounced reduction than that observed in the check 

 experiment. 



