Date Endosperm for Self- Digestion. 75 
used. This quantity of powder was digested fifteen hours in the refrigerator 
(12 0 C.) in 1500 cc. of tap-water which had been filtered through a 
Berkefeld filter. No antiseptics were used, the low temperature sufficing 
to inhibit putrefaction, as was shown by the neutral reaction of the filtered 
extract. The test for tannin in the filtered extract was negative, so 75 cc. 
of it were delivered from pipette into each of four beakers. Two of 
these beakers, group 1, were immediately evaporated to dryness over 
steam. The remaining pair, group 2, were digested eight days at 35 0 C. 
During this period a strength of 5 per cent, toluol was maintained. The 
beakers were covered with a watch crystal and stirred daily. After 
evaporating to dryness the duplicates of group 2, all four beakers were 
then extracted with 95 per cent, alcohol by boiling for three hours. 
After cooling and decanting over night, the alcoholic extracts were 
filtered into four tared beakers and evaporated to dryness over steam. 
The residues thus obtained were dried to constant weight at 120° C. 
and being very hygroscopic were cooled in the desiccator and weighed 
as rapidly as possible. The duplicates of group 1 were respectively 
•5765 grm. and *5805 grm., while those of group 2 were *5465 grm. 
and *5610 grm. Evidently the quantity of monoses in solution did 
not increase and hydrolysis could not have occurred. Since the aqueous 
extract contains non-reducing carbohydrates, which are converted into 
reducing sugars by the action of dilute acids, no reason is apparent why 
hydrolysis should not have taken place, if any enzyme were present, 
unless it might be that the non-reducing carbohydrates were present 
in sufficient amount to inhibit any enzyme action. That this was not 
the cause of the negative result seems clear from the results of subsequent 
experiments. That the temperature of digestion was favourable must 
be assumed because the seed germinates much more rapidly at this 
temperature than at lower ones. 
Experiment No. 2. Is the endosperm powder capable of auto- 
digestion ? Into each of four beakers 25 grms. of powdered endosperm 
were placed. The weighing itself was accurate, but no attempt to get 
the actual weight of the powder was made, the moisture remaining 
after three days’ exposure to room temperature after grinding being 
included. Into each of two of these beakers 75 cc. of 1 per cent. CuS 0 4 
were delivered from pipette, and into each of the remaining two were 
placed 75 cc. of 1 per cent toluol. All four beakers were incubated 
ten days at 35 0 C., being stirred daily and the toluol renewed. On the 
tenth day the liquor from each beaker was filtered, and into four tared 
beakers 50 cc. of each filtrate were respectively placed. The anhydrous 
alcohol soluble residues were: toluol, *4326 grm. and -4110 grm. ; copper 
sulphate, -4400 grm. and -4647 grm. The latter residues were coloured 
by the copper sulphate and no doubt a small amount of the latter was 
