86 Green. — On Vegetable Ferments. 
acts very slowly, producing gradually a liquefaction of the 
paste and a subsequent conversion of the starch with sugar. 
When allowed to act upon a true solution of starch, the so- 
called soluble starch, the transformation into sugar is rapid. 
The solution of starch can be prepared by the method of 
Kjeldahl, by acting on starch- paste with a little malt-extract 
and boiling the mixture as soon as liquefaction is complete, 
or preferably by that of Lintner, preparing the solution by 
acting on the starch-paste with dilute hydrochloric acid and 
subsequently neutralising. 
Another and more active form of diastase has been de- 
scribed by several observers, notably Brown and Morris 1 and 
Haberlandt, as being formed at the onset of germination in 
the seeds of several members of the Gramineae. To dis- 
tinguish it from the former variety Brown and Morris have 
given it the name of c diastase of secretion/ the first being 
called by them f translocation-diastase.’ They speak of it 
as originating, shortly after germination begins, in the epi- 
thelial cells covering the scutellum. The conversion into sugar 
of the grains of starch in the endosperm starts just under 
the scutellum and proceeds gradually towards the distal 
portion of the seed. The mode of dissolution of the starch- 
grains is essentially different from that caused by translo- 
cation-diastase. They become irregularly pitted, the fissures 
increase in number and depth, the outline of the grain be- 
comes irregular and its laminae separate from each other, the 
grain becoming completely disintegrated before it disappears. 
The process is hence one of corrosion rather than of solution. 
When a solution of this form of diastase is mixed with starch- 
paste it rapidly liquifies it, converting it subsequently mainly 
into sugar. Embryoes removed from germinating barley- 
seeds and allowed to rest upon various preparations of starch- 
paste, and of gelatin containing starch-grains in suspension, 
were found to have a similar power of corroding and dis- 
solving the granules, the latter undergoing the same changes 
as in the uninjured germinating seed. 
1 op. cit. 
