864 METHYL L.EVO-INOSITOL IN A POISONOUS PLANT, 



AV'heii converted to hevo-iiiositul (1), however, there would 

 a}>}>e;ir to be two groups of melting-point figures, one 10° higher 

 lljcin the other, but since there can be only one possible /-inositol, 

 this dili'erence nuist be otheiwise explained. 



The Table also shows that while the dextro- and Itevo-inositols 

 (3 and 4) are optical antipodes of one another, their esters (1 and 

 2) are not. The optical properties especially ai'e so very diver- 

 gent that, in all probability, the methyl group occupies a different 

 position in the two compounds. Tlie compound isolated from 

 Heterodendron is, therefore, shown not to be an optical isomer 

 of Maquenne's pinite. 



Biochemical Relationships and Significance. 

 (a) The chemical aspect. — Since the researches of Maquenne, 

 cited in the previous paragraphs, no subsequent w^ork has shown 

 any relationship between the inositols and the carbohydrates, 

 other than the sweet taste and the molecular formula common to 

 both. Perhaps one exception to this is found in Neuberg's iden- 

 tification of furfural among the products of decomposition, when 

 inositol is boiled with acids."^ Although furfural is also obtained 

 from the hexoses and heptoses in small amounts (about 0'2 /^), it 

 is characteristic of the pentose sugars. It must be also remem- 

 bered that the production of furfural is the basis of Molisch's 

 group-test for all carbohydrates, and with this reagent the 

 inositols gave negative results. 



However, it seems probable from the results of many workers 

 that the hexamethylenes form a kind of stepping-stone between 

 the open chain compounds and the true benzene ring derivatives. 

 Ojjoi chain camps. Closed ring camps. 



hexose sugars hexamethylene derics. Benzene derivs. 



dulcitol (juercitols phenols 



mannitol inositols 



sorbitol 

 The hexamethylene derivatives are much more easily decom- 

 posed than the simple benzene compounds. In fact, it has been 



* Biocheni. Zeitschrift, ix., 1908, 551. 



