cells to maintain the tension. With Eadie we have found that the free
glucose extractable from the muscles by warm alcohol is reduced following
the injecting of insulin, but we know nothing of the fate of the glucose
which disappears. It is not converted into glycogen (McCormick, Noble
and Macleod, Dudley and Marrian, Cori etc.) nor is it immediately oxidi-
sed, since the respiratory metabolism (intake 02 and R. Q.) does not be-
come increased at the time when the blood sugar is falling (Eadie, Dickson,
Macleod and Pember; Trevan and Boock; Krogh; Boothby and Wilder etc.).
Although the intake of oxygen may become greater in certain animals
such as dogs, cats and man when hypoglycaemic symptoms make their
appearance this does not occur when sugar is also administered. In light
of these results we have concluded that the glucose which disappears must
become converted into some hitherto unidentified substance, but we have
been unable to obtain any clue as to what this substance may be. Large
amounts of it must be formed to account for the enormous quantities of
glucose which may vanish from the blood, as when glucose is injected
along with insulin. We have, for example, injected into rabbits, in the
course of 8 hours, as much as Io grams of glucose per kilo body weight
along with insulin without finding, at the end, any increase in blood sugar.
or in the free or the combined sugar of the muscles or liver. Burn and
Dale have also shown that very large quantities of glucose can be injected
along with insulin into eviscerated animals without increasing the percentage
of the blood sugar. It is conceivable that between glucose and the ma-
terial which is finally oxidised in the tissues there exists, not one, but a
group of substances constantly changing from one into another in an
equilibrated system, and that no one of them ever accumulates in sufficient
quantity to make its identification possible by available chemical methods.
Be this as it may, it is significant that the percentage of inorganic
phosphoric acid in the blood declines at the same rate as the sugar, al-
though, in the recovery process, the phosphoric acid begins to rise deci-
dedly before the sugar in animals injected with insulin. Accompanying this
fall in the phosphates of the blood, those of the urine entirely disappear
for several hours and then return to considerably above the normal level
so that, in urine collected throughout the 24 hours, an excess is excreted,
I
Practically all observers have confirmed the observation first nade by Dickson and
Pember that R. Q. rises somewhat in normal animals injected with insulin but the extent of
this tise is' not sufficient to indicate that increased combustion of glucose can be the significanrt
cause for the rapid reduction in blood sugar.