88 Green. — On Vegetable Ferments . 
cannot be induced in the epithelium-cells of the scutellum 
without previous expulsion of moisture. 
The two varieties of diastase may be thus compared — 
(1) Translocation-diastase. — Dissolves starch-grains with- 
out corrosion ; has a very slow action on starch-paste, though 
it readily converts soluble starch into sugar ; works best at 
a temperature of 45-50° C. ; is much more energetic at a low 
temperature than secretion-diastase. 
(2) Diastase of secretion. — Corrodes starch-grains and 
disintegrates them before solution ; rapidly liquefies starch- 
paste ; works most advantageously at a temperature of 50- 
55 ° C. 
The action of diastase is one of hydrolysis. It is very 
rapid up to a certain definite point, when the mixture is 
found to consist of maltose and dextrin in the proportion of 
about four parts of the former to one part of the latter. The 
intermediate decomposition is of a very complex character. 
The most recent hypothesis is that advanced by Brown and 
Morris in 1889 1 . They suggest that the starch-molecule has 
a formula of 5(C 12 H 20 O l0 ) 20 and is composed of five amylin 
or dextrin-like groups, four of the latter being arranged about 
the fifth. The first act of hydrolysis is the liberation of them 
from one another, four of them, by successive hydrolysations, 
being then converted through a series of amyloins or malto- 
dextrins to maltose, while the fifth withstands for a long 
time the action of the ferment. When the transformation 
of the four groups is complete, the condition noted above 
is arrived at, the proportion of maltose to dextrin being 
as 4 : 1. 
The products which are formed in the plant by diastase 
have not been so completely examined. The final product 
of the starch is apparently maltose, but very little is known 
at present about the intermediate bodies by actual experi- 
ment. 
The conditions under which malt-diastase works most 
1 On the analysis of a beer of the last century : Transactions of the Laboratory 
Club, No. 4, vol. Ill, February 1890. 
