DIGESTION AND ABSORPTION 



159 



Carbohydrates 



QUESTIONS AND PROBLEMS. 



I. Monosaccharids 



II. Disaccharids 



III. Polysaccharids 



(a) How may carbohydrates be classified? (Make three classes.) 

 (6) Which class has the lowest grade of hydration? 



(c) How many of this class are soluble in cold water? 



(d) How many are diffusible? 



(e) Which class has the highest grade of hydration? 



(/) Are all of those which belong to Classes I. and II. soluble in 

 water ? 



(g) Which are diffusible? 



(h) How many of the carbohydrates reduce CuSO 4 in the presence 

 of an excess of NaOH or KOH? 



(i) How many of the carbohydrates are diffusible? 



(j) How may one determine whether or not cane-sugar passed 

 through the animal membrane? 



II. SALIVARY DIGESTION. 



1. Materials. Bread; fibrin; pig-fat; olive oil; starch paste; 

 cane-sugar. 



2. Preparation, (a) Remove the parotid and submaxillary glands 

 of several rabbits or rats, hash them, rinse quickly with water to 

 remove blood, and cover with water. After a few hours (twelve to 

 twenty-four) filter or strain off the opalescent, aqueous extract. It 

 should contain an aqueous solution of ptyalin. Label: Salivary 

 Extract. 



(b) Chew a piece of rubber or paraffin. The flow of saliva is 

 stimulated; catch the secretion in a beaker; dilute and filter. Label: 

 Salivary Secretion. 



(c) Fibrin for use in experiments on digestion may be procured 

 in any quantity at a slaughter-house. Rid it of all red coloring 

 matter and of accidental contamination by repeatedly soaking and 

 washing in water. The white, elastic threads of fibrin may be kept 



