188 MANNITE. 



the constitution expressed by the formula CEP.OIL 

 CH.OH.CH.OILC.OH j Qjp OH. 



1. Mannite. 

 C 6 H 14 6 = C 6 H 8 (OH) 6 . 



Occurrence. Pretty widely distributed. In celery, 

 in spo'nges, in sea grasses, in the wood of Pinus larix, 

 in the bark of Canella alba; most particularly, how- 

 ever, in manna, the dried juice of Fraxinus ornus. 



Formation. During the fermentation of sugar under 

 certain circumstances. By the action of nascent 

 hydrogen (sodium-amalgam) on grape-sugar. 



Preparation. Manna is dissolved in boiling alcohol, 

 and, when the solution cools, mannite crystallizes out ; 

 by pressing and recrystallization, it is purified. 



Properties. Crystallizes from alcohol in fine, color- 

 less crystals; from water in large, clear prisms. Of 

 very sweet taste, easily soluble in water. Fusing 

 point, 166. It does riot reduce an alkaline solution 

 of copper subchloride nor the solutions of the noble 

 metals. In contact with cheese and chalk it is resolved, 

 at 40, into hydrogen, carbonic anhydride, alcohol, 

 and lactic, butyric, and acetic acids. In aqueous solu- 

 tion, in contact with platinum-black or with testicle- 

 substance for some time, it is converted into a syrupy 

 sugar, mannitose C 6 H 12 6 , which is capable of under- 

 going fermentation. "When heated with concentrated 

 hydriodic acid, it yields 0-hexyl iodide (p. 72). It 

 combines with bases forming amorphous, easily de- 

 composable compounds. 



Mannite nitrate (nitromannite), ^ C 6 H 8 (0.]TO 2 ) 6 , is 

 formed by treating mannite with a mixture of concen- 

 trated sulphuric and nitric acids. Fine prisms, easily 

 soluble in hot alcohol. Fuses at 72 ; and detonates at 

 120, or under the hammer, with a sharp report. 



Mannite acetate, C 6 H 8 (O.C 2 IPO) 6 . Is produced by 

 heating mannite for a long time with acetic anhy- 



