eta], C_{24}H_{42}O_{21} (previously named by Prior,
achroodextrin III.). They also separated a substance, C_{12}H_{22}O_{11},
isomeric with maltose, which had, however, the characteristics of a
dextrin. This is probably identical with the so-called dextrinose isolated
by V. Syniewski in 1902, which yields a phenylosazone melting at 82-83 deg. C.
It has been proved by H. Ost that the so-called isomaltose of Lintner is a
mixture of maltose and another substance, maltodextrin, isomeric with Ling
and Baker's maltodextrin-[beta].

The theory of Brown and Morris of the degradation of starch, although based
on experimental evidence of some weight, is by no means universally
accepted. Nevertheless it is of considerable interest, as it offers a
rational and consistent explanation of the phenomena known to accompany the
transformation of starch by diastase, and even if not strictly correct it
has, at any rate, proved itself to be a practical working hypothesis, by
which the mashing and fermenting operations may be regulated and
controlled. According to Brown and Morris, the starch molecule consists of
five amylin groups, each of which corresponds to the molecular formula
(C_{12}H_{20}O_{10})_{20}. Four of these amylin radicles are grouped
centrally round the fifth, thus:--

(C_{12}H_{20}O_{10})_{20} (C_{12}H_{20}O_{10})_{20}
\ /
(C_{12}H_{20}O_{10})_{20}
/ \
(C_{12}H_{20}O_{10})_{20} (C_{12}H_{20}O_{10})_{20}

By the action of diastase, this complex molecule is split up, undergoing
hydrolysis into four groups of amyloins, the fifth or central group
remaining unchanged (and under brewing conditions unchangeable), forming
the substance known as stable dextrin. When diastase acts on starch-paste,
hydrolysis proceeds as far as the reaction represented by the following
equation:--

5(C_{12}H_{20}O_{10})_{20} + 80 H_2O
starch. water.
= 80 C_{12}H_{22}O_{11} + (C_{12}H_{20}O_{10})_{20}
maltose. stable dextrin.

The amyloins are substances containing varying numbers of amylin (original
starch or dextrin) groups in conjunction with a proportional number of
maltose groups. They are not separable into maltose and dextrin by any of
the ordinary means, but exhibit the properties of mixtures of these
subs