1907] VINSON—INVERTASE IN DATES 397 
fruit. They explained this erroneously by considering that the 
acidity of the leaf was insufficient to invert the cane sugar, and 
only after it reached the acid fruit could such inversion take place. 
The occurrence of some cane sugar in the earliest stages of growth of 
the cherry, and its subsequent disappearance, they also attribute to a 
lack of acid. BuIGNET? attempts to explain the high cane sugar con- 
tent of some strawberries in much the same way, on the hypothesis 
that the sugar and acid exist in different cells, and that in the watery 
varieties diffusion and consequently inversion take place more 
rapidly than in drier berries. In a later paper?® he concludes that 
acidity has nothing to do with the inversion, but that it is probably 
the work of a “‘nitrogenous ferment.” In the date acidity has nothing 
to do with inversion, for the cane sugar dates are usually the more 
acid. Neither does the high acidity of the orange appear to deter- 
Mine inversion, for here the cane sugar increases during ripening, 
while the invert sugar remains nearly constant. This BERTHELOT 
and BuicNet?’ think is especially remarkable, since the green fruit 
contains no starch from which to derive the cane sugar. The phe- 
nomenon, however, is almost identical with that of the cane sugar 
date and just what would be expected of any fruit having similar 
invertase relations. The accumulation of starch in the stem of fruits 
which contain none appears to be quite common and has been 
observed in the grape.?® Whether or not this is the case with the 
date has not been determined. 
While the observed fact that cane sugar accumulates at the time 
of maximum ripening in nearly all fruits, even the pea?® and cucur- 
bits,3° points very strongly to that sugar as the original carbohydrate 
to enter the fruit, one point militates most powerfully against such a 
hypothesis; the partial osmotic pressure of cane sugar within the 
date would stop flow in that direction long before the high observed 
25 Résumé, Compt. Rend. 49:276-278. 1859; through Bull. 94, Bur. of Chem. 
26 Compt. Rend. 51:894. 1860; ibid. 
27 Compt. Rend. 51:1094. 1860; ibid. ; 
28 FamIntzin, Ann. Oenol. 2:242. 1871; and Hitcer, Landw. Vers. Station 
1'7:245. 1874; through Ker, Joc. cit. 
20 SCHWARZ AND RIECHEN, Zeits. Unters. Nahr. Genuss. 1904:550; and FRE- 
RICHS AND RopENBERG, Arch. Pharm. 243:276. 1905. 
3° LECLERC DU SABLON, Compt. Rend. 1402320, 321. 1905. 
