THE CARBOHYDRATES. 7 



2. Place 10 c.c. of the saccharose solution in a test-tube 

 with 5 c.c. of 1 per cent HC1. Allow the mixture to remain 

 two hours at 37 C. Finally examine this in the polariscope 

 and test its reducing power. To what condition in the body 

 is this comparable? 



3. To 10 c.c. of the saccharose solution add some invertin 

 and allow the test-tube to remain at 37 C. Test for invert 

 action. 



4. See demonstration of the formation of alcohol and 

 C0 2 from a fermentation of cane-sugar by yeast. The C0 2 

 as it forms is caught in passing out of the flask by a valve of 

 Ba(OH) 2 . The alcohol is distilled off from the mixture in 

 the flask. 



MALTOSE will be studied under Salivary Digestion and 

 LACTOSE under Milk. 



POLYOSES OR POLYSACCHARIDES, (C 6 H 10 5 )- 



STARCHES. DEXTRINS. GLYCOGEN. CELLULOSES. 

 VEGETABLE GUMS. 



The polysaccharides, as a class, are amorphous, more or 

 less insoluble substances which do not diffuse through animal 

 membranes. They are optically active, and with the excep- 

 tion of the dextrins do not reduce Fehling's solution. By 

 hydration with weak acids or with enzymes the polysac- 

 charides are converted into monosaccharides ; dextrins and 

 disaccharides being the intermediate products. The polysac- 

 charides are incapable of undergoing fermentation unless 

 previously inverted. 



STARCHES. 



The starches are insoluble bodies which, with hot water, 

 form opalescent colloidal solutions or pastes. These, if suffi- 



