30 



Dse. MMsugfar (Ci^H.^On+H^O). The reduc- 

 maltose is one third less than dextrose. Maltose 

 jfe ifaililrtransformed into dextrose by acids and ferments, 

 dextrose cannot be converted into maltose. Maltose must 

 transformed into dextrose before it can be absorbed into 

 the blood. One molecule of maltose decomposes into two 

 molecules of dextrose. Use a 2% solution of maltose. 



88. Apply Barfoed's test to a portion of the maltose 

 solution and compare with dextrose. 



89. Apply the phenyl-hydrazine test and compare the 

 crystals with those obtained in the dextrose solution. 



90. To other portions of the maltose solution apply 

 Trommer's, Fehling's, and Boettger's tests respectively, and 

 compare with dextrose. 



V 



91. Fats. The fats occur in both plants and animals. 

 They are insoluble in water and have a lower specific gravity. 

 They dissolve in hot alcohol more easily than in cold, and 

 are easily soluble in ether, gasoline, or benzol. 



Fats are composed of three elements : carbon, hydrogen, 

 and oxygen. They contain a much smaller percentage of 

 oxygen than the carbohydrates, the hydrogen and oxygen not 

 being in the proportion to form water. When the fats are 

 kept at the temperature of superheated steam or subjected to 

 the pancreatic enzyme — steapsin, they take up water and are 

 split into two compounds : glycerine, on the one hand, and one 

 or more of the fatty acids, on the other. They may be con- 

 sidered, then, as made up of glycerine and a fatty acid less 

 water. 



This splitting u^ of the fat molecule is called saponifica- 

 tion. It occurs when fats become rancid. It can also be 

 effected by boiling the fat with a caustic alkali. Here, in- 

 stead of the free fatty acid being left, it unites with the 

 alkali to form a salt. These metallic salts of a fatty acid are 

 the soaps. The soaps of the alkalies are soluble in water, the 

 potassium compound being hygroscopic and forming soft 

 soap. The sodium compound forms a hard soap. 



