SUGAR OF BLOOD. 109
in a variety of ways. We determined his blood sugar next day by Bang's
method, and obtained the figure .12 p.c., which would tend to support
this view.
One experiment was made on a case of cerebral hæemorrhage in which
there was sugar in the urine. The subject was on a milk diet, was comatose
and apparently unconscious that blood (100 c.c.) was being drawn.
A large amount of sugar was present in the blood. The ratio polarimeter
to copper reducing value was however much below that of the diabetic
cases. The polarimeter value attained the copper value in 12 hours, the
short time being no doubt due to the difference between them being
originally slight. Thus the change was like that of normal, and not like
that of diabetic subjects in which the polarimeter value approaches the
copper line from the upper side.
Discussion.
The nature of the normal blood sugar we leave for the present
undecided. Since the sugar yields an osazone having the same melting
point as glucosazone, and the same microscopic appearance, it is prob-
ably a hexose. The failure to obtain læevo-rotation may possibly have
been due to a rapid change in the sugar notwithstanding the care taken
to prevent it. Professor Hopkins suggested that if alcohol were used
throughout as a precipitant, alteration of the sugar might be prevented.
This was tried but the clear filtrate was dextro-rotatory.
The method takes much more time than that with tungstic acid. Alcohol allows fatty
substances to pass into the filtrate, whilst by the tungstic acid method almost the whole
of the fatty bodies remain entangled in the precipitate; and it was only after repeated
filtering in the various stages that a clear fluid suitable for polarimetric observations was
obtained.
On applying Seliwanoff's test for fructose, negative results were
obtained, indicating the absence of læevulose and pseudo-laævulose (iso-
glycuronic acid).
The sugar we consider is some form of glucose. We have seen that
the. polarimetric readings finally reach a value corresponding to that
given by a, f glucose in equilibrium. Further experiments on the final
filtrate as soon as obtained showed that KMnO4(12) was decolourised
with great rapidity when compared with a solution of glucose of equal
concentration; but after being allowed to stand for some days until the
polarimeter reading has risen to a value corresponding to that of a, f
glucose, the decolorisation is slow and approximates to that of a,
glucose. It is suggested therefore that the decolorisation by the fresh
filtrate is due to the sugar and not to some impurity. It is in harmony
with this view that, according to Hewitt and Pryde(s), sugar solutions