197 



3. Lactose. 

 C 6 H 12 6 . 



Formation. From sugar of milk by heating with 

 dilute acids ; together with another variety of sugar, 

 that appears to be grape-sugar. 



Properties. Easily soluble, microscopic crystals, 

 united in nodules. Does not combine with sodium- 

 chloride. Its solution rotates the plane of polarization 

 towards the right, more strongly than that of grape- 

 sugar. Exhibits the same conduct towards an alka- 

 line copper solution, and in connection with fermenta- 

 tion, as grape-sugar; yields, however, mucic acid, on 

 being heated with nitric acid. 



4. Sorbine, C 6 H 12 6 , in the juice of the berries of 

 the mountain-ash. Large, colorless, easily soluble 

 crystals. Not capable of fermentation with yeast. 

 When oxidized, it yields aposorbic acid (p. 187) 

 together with tartaric and racemic acids. 



5. Inosite (phaseomannite), C 6 H 12 6 +2H 2 0. Occurs 

 in the animal organism, particularly in the muscular 

 substance of the heart; is, however, also contained in 

 the lungs, kidneys, liver, spleen, in the brain ; and, in 

 certain diseases (Morbus Brightii), it has also been 

 detected in the urine. Occurs, further, pretty widely 

 distributed in the vegetable kingdom, particularly in 

 the unripe fruits of many papilinaces (beans, peas, 

 lentils, acacias), in cabbage, in Digitalis purpurea. Ta- 

 raxacum officinalc, in the shoots of potatoes, in the 

 green portions and the unripe berries of asparagus, in 

 the leaves of Fraxinus excelsior, in grape-juice, etc. 

 Large, colorless, rhombic crystals of a sweet taste, 

 losing their water of crystallization in the air and 

 becoming white and opaque. Easily soluble in water, 

 insoluble in absolute alcohol and in ether. Fuses at 

 210. Not capable of fermentation with yeast. Eva- 

 porated nearly to dryness with nitric acid, then mixed 

 with an ammoniacal solution ol calcium chloride and 



17* 



