1907] VINSON—INVERTASE IN DATES 405 
Deglet Noor was prepared and found to contain, per liter, go. 32™ 
cane sugar, 18.818” fructose, and 17.788" glucose. A similar arti- 
ficial mixture was made and both treated with equal amounts of 
Rhars extract. The natural Deglet Noor extract was inverted slightly 
faster than the artificial one. This proved that no antiferment was 
present. 
While glycerin extracts of Deglet Noor and M’Kentichi Degla 
fail to invert solutions of cane sugar, the presence of considerable 
quantities of invert sugar in these dates points with certainty to inver- 
tase. It is untenable, moreover, to consider that these dates differ 
from the invert varieties merely in quantity of invertase without other 
qualifications, for a very small amount of invertase will invert a very 
great amount of cane sugar. O’SULLIVAN found that one part of 
crude invertase inverted 100,000 parts of cane sugar and still retained 
its inverting powers. It must be remembered also that a significant 
amount of invert sugar is formed in a very short time about the period 
of softening, and that this amount is greater under changed condi- 
tions, especially the higher temperature and moisture required for 
artificial ripening. The inverting action, however, is limited, for 
cane sugar determinations in samples one year old showed for Deglet 
Noor 42.14 per cent., M’Kentichi Degla 59.05 per cent., Saffraia 
2.96 percent. Thesame sample of Saffraia one year before contained 
nearly 4 per cent. cane sugar. This failure to invert is not due to the 
invertase becoming inactive, for a Rhars extract made from dates 
stored one year was fully as active as fresh date extract. A portion 
of the pulverized Saffraia used above, tested for inverting powers, 
proved to be one of the strongest preparations examined. These phe- 
nomena seem to be due to the localization of the invertase, which 
means suppression of invertase-secreting tissue. The only thing that 
could have prevented the inversion of the residual cane sugar in the 
Saffraia must have been inability to come into molecular contact with 
the enzyme. The tissues of all dates exhibit inverting powers, 
although the cane sugar varieties show it but feebly. The failure of 
their glycerin extracts to invert is probably due to the very small 
amount of invertase remaining in the same condition as it exists in 
the green invert sugar date. 
Two ways suggest themselves for studying the distribution of the 
