PHYSIOLOGICAL CHEMISTRY. 



Note the absence of any true sugar group or free ketone or alde- 

 hyde group. 



FIG. 6. 



Sucrose. 



EXPERIMENTS ON SUCROSE. 



i-u. Repeat these experiments according to the directions given 

 under Dextrose, pages 23-31. 



12. Inversion of Sucrose. To 25 c.c. of sucrose solution in 

 a beaker add 5 drops of concentrated HC1 and boil one minute. 

 Cool the solution, render alkaline with solid KOH and upon the 

 resulting fluid repeat experiments 3 (or 4) and 9 as given under 

 Dextrose, pages 24-26. Explain the results. 



13. Production of Alcohol by Fermentation. Prepare a 

 strong (10-20 per cent) solution of sucrose, add a small amount 



of egg albumin or commercial peptone 

 and introduce the mixture into a bottle 

 of appropriate size. Add yeast, and by 

 means of a bent tube inserted through a 

 stopper into the neck of the bottle, con- 

 duct the escaping gas into water. As 

 fermentation proceeds readily in a warm 

 place the escaping gas may be collected 

 in a eudiometer tube and examined. 

 When the activity of the yeast has prac- 

 tically ceased, filter the contents of the 

 bottle into a flask and distil the mixture. 

 Catch the first portion of the distillate separately and test for alco- 

 hol by one of the following reactions : 



(a) lodoform Test. Render 2-3 c.c. of the distillate alkaline 

 with potassium hydroxide solution and add a few drops of iodine 



IODOFORM. (Autenrieth.) 



