110 L. B. TWINTER AND W. SMITH.
introduced into the intestine undergo a rapid downward muta-rotation.
The enzyme responsible for the conversion being apparently absent from
the blood, and the reaction of the blood being alkaline, suggests that it is
impossible for so reactive a sugar to exist free in the blood. The
combination, if combination there is, must be of the nature of an unstable
glucoside for it is well established that the sugar of the blood is readily
Experiments after taking glucose and fructose indicate that these
sugars are rapidly changed into the normal form present in blood.
Nef(r3) suggested that the reaction d-fructose - glucose must take place
with the intermediary formation of an enolic form. It is probable then
that the normal blood sugar is y glucose, and that it arises from the
While the work of Hewitt and Pryde(9) may account for the
formation of y glucose owing to passage through the intestinal wall,
some further explanation is necessary as regards the sugar which is
formed from glycogen. The experiment with J. C. C. P. suggests that
y glucose is formed not directly by glycogen breakdown, but as the
result of the interaction of some other mechanism. We may therefore
picture the processes:
glycogen - a, f glucose -> y glucose occurring.
For the first stage of this process the liver diastase is the active agent,
for the second stage the work of Clark(2, 3) suggests that the pancreas
We have confirmed Hewitt and Pryde's observations(s) that ex-
tracts of the mucous membrane of the intestine do not alter the specific
rotation of glucose solutions in vitro, and we can only suggest that as
the result of some stimulus the pancreas secretes an enzyme, or enzymes,
which cause the change a, f glucose -> y glucose. Some experiments
on which we are at present engaged tend to support this view.
The marked difference shown between the curves of polarimetric
readings obtained from normal subjects and severe diabetic patients
throws a new light on the etiology of the disease. It is probable that
glucose can only be stored and utilised after passing through the y form,
and that the severity of diabetes depends on the degree to which the
power to form this sugar is lost. In the severe cases which we have
examined there was no y glucose which we were able to detect, any
small amount present being masked by the large amount of other sugar
in the solution. This would be especially the case in the diabetic where
the very high ratio polarimeter to copper value suggests that a certain