BY JAMES M. PKTRIE. 



859 



Forms and angles. 



The Inositols. 



Position of the group. — The relative positii^ii of the group, and 

 the mode of occurrence of its members in nature, are of consider- 

 able interest to the biochemist, especially since the discovery of 

 "phytin" in plants by Paladin, in 1895. 



The basis of inositol is the hexamethylene ring (CH..),.. 

 Hexamethylene, C„H^^ (Text-fig. 1 ), occurs only in the hydro- 

 carbons of the petroleum of Russia, Galicia, Baku, East Indies, 

 and California, in the fraction boiling about 80°C. It has not 

 been detected in plants or animals. 



By the substitution of hydroxy! groups (OH) in the hexametliv- 

 lene ring, the following series of compounds is obtained: — 

 (OH), (OH).^, (OH).. — synthetic compounds only. 

 (OH)^ — betite, isolated from beet sugar residues. 

 (OH)- — quercite, in oak and other plants. 

 (OH),; — inosite, in many animals and plants. 



Inosite, or inositol, has, therefore, the constitution ^)i a liexa- 

 hydroxy hexamethylene C,.H,. ' (OH),., and although its formula 

 may be written C\;H^^O,., it is nevertheless, in its relationships, 

 far removed from the carbohydrates. 



Tha couistituJion of Inositol. — The configuration of the inositol 

 molecule, or, in other words, the arrangement of its at<jms in 

 space, admits of eight different geometrical groupings resultinij 

 in eight possible isomeric foi-ms. When these and their mirror- 

 images are built up in models, it is found that seven of the forms 

 may be superimposed on, and, therefore, coincide with, their 



