409 BOTANICAL GAZFTTE [JUNE 
It is true that no catalytic outside the living cell is known which 
will transform maltose into cane sugar, but the cell is known to do so 
and the catalytic will probably be discovered. The transformation of 
starch to cane sugar seems to be established for the banana and apple, 
but here again no catalytic is known that will cause the transforma- 
tion, although many, and some of organic origin, transform it into 
maltose. Brown and Morris, moreover, have shown maltose to be 
the final product of starch hydrolysis in the leaf. Thus it seems 
probable that in these cases starch changes to cane sugar through 
maltose. It is also probable that the speed of transformation, maltose 
to sucrose, is very considerable, since BicELow and Gore? find the 
curve representing the increase of cane sugar in a ripening apple to 
be nearly the reverse of that representing the decrease in starch. 
An examination of the accompanying table will reveal the chief 
points of interest in the development of the date, and also the diver- 
gence between the cane and invert sugar varieties. The cane sugar 
date is represented by the fruits of the Deglet Noor33 from palms 
imported from the oasis of French Algeria in 1900. The invert sugar 
date is from a seedling palm of excellent quality growing upon the 
university campus and immediately accessible from the laboratory. 
It seems that any attempt to interpret a series of date analyses, 
made at different stages of growth, by reducing them to the dry basis, 
can give only a partial idea of what is actually taking place. Water 
has as much to do with the changes as cane sugar or invert sugar. A 
date having 20 per cent. of dry matter may change in a few days to 
one of 60 per cent. in three ways: by the loss of water through transpi- 
ration with decrease in weight; by the addition of dry matter without 
loss of water, possibly some gain, and increase in weight; or by the 
addition of dry matter with loss of water and little or no change in 
weight. In the case of the cherry, Ker has noted that the period of 
maximum increase in percentage of dry matter in the fruit is parallel 
with that of maximum increase in weight. In the peach>+ the increase 
in solids is fairly proportional to the increase in water. With the date 
there is a more or less parallel increase in percentage of dry matter and 
3? Bull. 94, Bur. of Chem., U.S. Dept. Agric. 
33 SWINGLE, Bur. Plant Ind., U. S. Dept. Agric. Bull. 53:33. 
34 BIGELow and Gore, Bur. of Chem., U. S. Dept. Agric. Bull. 97: 12. 
