7 o 
Pond . — The Incapacity of the 
All the figures represent anhydrous weight in grams. Three ratios 
of enzyme to starch were tried in duplicate. The starch solution contained 
in i cc. 0*01625. The enzyme solution contained in 1 cc. 0*00160. Titration 
closer than *i cc. not attempted. 
Enzyme. 
Starch. 
Hydrolytic Product. 
No. i — 0*004960 
0*500 
0*4700 
No. 2 — 0*004960 
0*500 
0*4700 
No. i — 0*002560 
0*500 
0-4870 
No. 2 — 0*002560 
0*500 
0 - 495 ° 
No. 1 — o*oo 1 60 
0*500 
0-4180 
No. 2 — 0*00160 
0*500 
0-4150 
These figures show that a reasonably accurate determination of hydro- 
lytic product can be made with varying dilutions of enzyme. Such a deter- 
mination is far more satisfactory than the usual colour method with iodine. 
The enzyme used was advertised to convert into dextrine and maltose 
250 times its own weight of starch in three hours at about 40° C. The fact 
that the hydrolytic product for the ratio 1 : 200 is greater than that for 
the ratio 1:100 is to be attributed to difference in digestion conditions, since 
no attempt at comparison was made except for the duplicates of a given 
ratio. As dextrine is known to be one of the products of enzyme activity, 
since dextrine is insoluble in 95 per cent, alcohol, it is evidently excluded in 
this method. Since the ratio of the hydrolytic product thus obtained is so 
constant for a given ratio of enzyme to starch, it must be regarded as a very 
convenient and accurate method for testing the hydrolytic capacity of 
a given enzyme. 
In applying this method to the study of the Date it was found necessary 
to evaporate to dryness and then extract with alcohol instead of depending 
upon the alcohol to precipitate all unhydrolized matter. This evaporation 
must continue until the residue is hard. If to the viscous residue alcohol 
be added, some of the carbohydrates, though insoluble in alcohol, mix with 
it and when heated an apparently clear solution is obtained. The alcoholic 
extract should cool to room temperature before filtering. Failure to 
observe these precautions gave me results from which a conclusion contrary 
to the one here given was published 1 . 
During extraction with alcohol the beakers were covered with watch 
crystals thus making a sort of reflux condenser. 
Properties of the aqueous extract . — The powdered endosperm (400 grms.) 
prepared as described above yields, after about six hours’ digestion with 
distilled water (1,200 cc.), a liquid which when filtered has the following 
properties. It is neutral to litmus and remains neutral until by putrefaction 
it becomes acid. It does not contain tannin, as the test with ferric chloride 
1 Pond, ’ 04 , p. 1 81. 
