2?8 
Notes. 
34. Hymenophyllum demission . . . . . 4 20' 
35. Hydrocharis Morsus-ranae . . , . . 0-267 
36. Solanum tuberosum . . . . . . 8-163 
37. Nicotiana affinis ....... 7*524 
38. Ly coper sicum escu ten turn . . . . . 6-569 
We need not here describe the method by which the numbers were 
obtained, but will only remark that they are strictly comparable. 
They really represent the amount of maltose in grams which the diastase 
of ten grams of leaf is able to produce by hydrolysis from soluble starch 
in forty -eight hours at a temperature of 30° C. 
As an example of the accuracy of which the method is susceptible, 
we give the results of two determinations of diastase on the same 
sample of Tropaeolum- leaf 
(1) 4.96 
(2) 4-90. 
We see from the table that the foliage-leaves of all plants 
examined contain more or less diastase, but that the amount of 
enzyme varies enormously in different plants, and, within narrower 
limits, even in the same plant at different times. 
It will help us to realize the high diastatic power of some leaves if 
we compare them in this respect with an ordinary malt , acting under 
the same conditions. We see that the leaves of Pisum sativum contain 
a sufficiency of diastase to convert twenty-four times their own dry 
weight of starch under the standard conditions. Under these same 
conditions an ordinary pale barley-malt will convert sixty-three times its 
own weight of starch, so that we are led to the remarkable conclusion 
that the diastatic activity of the leaf of Pisum sativum is, weight for 
weight, between one-half and one-third of that of an average barley-malt. 
At the other end of the scale as regards diastatic activity, we have 
the leaves of Hydrocharis Morsus-ranae , which can only hydrolyze 
2-5 per cent, of their own dry weight of starch, but there is no doubt 
that in this case our method gives too low an expression of the 
diastatic activity owing to the large quantity of tannin which the leaf 
contains, and which partially inhibits the action of the diastase. 
It will be noticed in the table that the Leguininosae stand out 
pre-eminently for the high diastatic power of their leaves. The one 
exception is the Lupin, and here again we have to do with a leaf 
containing a good deal of tannin. 
