n8 SCIENCE PROGRESS 



fication, and deserves a short discussion as a substance common 

 to both animals and plants. Since its discovery in muscle by 

 Scherer in 1850 it has also been known as muscle sugar, 

 possessing the same molecular formula as the simple sugars 

 C 6 H 12 6 . 



It has, however, except its sweet taste and empirical formula, 

 nothing in common with sugars ; but Maquenne showed in 1887 

 that the constitution of a reduced hexa-oxy-benzene must be 

 ascribed to it : 



HOH 

 HOH/\HOH 



HOHS/HOH 

 HOH 



It represents one of the few known cases of optical activity in 

 the absence of an asymmetric carbon atom, as foreseen by Van't 

 Hoff and Le Bel's theory. Nine forms are possible, of which 

 two optically active and one inactive modification are known- 

 Inosite has been found since its discovery in nearly every 

 animal organ (brain, heart, spleen, kidney, etc.). In plants it 

 also occurs as a general constituent of roots and leaves, especially 

 growing leaves. 



Although we are still without any definite knowledge as to 

 its functions in the animal body, we may assume that it repre- 

 sents a transition stage from the carbohydrates to the benzene 

 derivatives. By a closing-up of the open chain of the carbo- 

 hydrate molecule its formation is theoretically possible from the 

 latter. On the other hand, the opening of the ring would give 

 rise to an open chain, and it has indeed been found that lactic 

 acid is formed from inosite by bacterial action — a fact recently 

 confirmed by Harden and Young. 



Organic Compounds of Phosphoric Acid. — A much clearer idea, 

 if not about its functions, so at least about the formation of 

 inosite in the plant, has been obtained through recent researches. 

 Winterstein was the first to notice that mustard seeds contained 

 the magnesium salt of an organic compound of phosphoric acid, 

 which on boiling with acids gives rise to inosite. Independently 

 of Winterstein, the same substance was also obtained by 

 Posternack, who was able to isolate it from leguminous seeds, 

 cereals, many oily seeds, and rhizomes. According to him, the 

 globoid of the aleurone grains represents the source of this 

 substance. Its chemical investigation showed an unexpected 



