344 The Dextrose- Laevulose Ratio in the Mamjold 



and 5) shows that it is possible to correlate the wide variations in the 

 differences (A) between the reduction and polarisation values for cane 

 sugar with the variations in the apparent dextrose and laevulose, a fact 

 which points to their having a common origin, namely the presence of 

 optically active impurities. Fig. 4 shows the variation of the apparent 

 dextrose and laevulose in the top half of the stalks and also the curves 

 for cane sugar and total hexoses. During the whole 24 hours the 

 "de.Ktrose" fluctuates only slightly — there is a slight rise and fall during 



Table VIII. 



Divergence of Results for Saccharose by Reduction and Polarisation 

 in Mangold Stalks — Series I. 



the day and a shght rise and fall at night. The saccharose also is nearly 

 constant during the 24 hours. But the "apparent laevulose" varies 

 enormously. Between 6 a.m. and noon this sugar increases from 

 nil to 4-5 per cent., but from noon onwards falls along almost a straight 

 hne until the zero is again reached shortly after midnight. The 

 important fact to be noted is that while the apparent laevulose increases 

 the differences (A) between the polarisation and reduction values of cane 

 sugar become more and more negative (change from -f 10 to — 90 for 

 invertase values, Table VIII), whilst when the apparent laevulose falls 

 the values of A become more and more positive (— 84 per cent, at 

 6 p.m., + 28 at midnight). It may be noted that the curve of apparent 



