At a recent meeting of the Clinical Society of London, Dr. Oliver gave
a demonstration of the method he employs for the detection of sugar
in the urine by means of test-papers. The test-papers were charged
with the carmine of indigo and carbonate of soda. When one was dropped
into an ordinary half inch test tube, and as much water poured in
as just covered the upper end, and heat applied, a transparent and
true blue solution, resembling Fehling's in appearance, was obtained.
(A transparent solution could not, at the meeting, be produced from
the London water. The characteristic reaction with grape sugar was,
however, unimpaired).
If with the paper one drop of diabetic urine had been added, shortly
after the first simmer, a beautiful series of color changes appeared;
first violet, then purple, then red, and finally straw color; while, on
the other hand, one drop of non-diabetic urine induced no alteration of
color. The colors returned in the inverse order on shaking the tube,
which allowed the air to mingle with the liquid. Reheating restored the
colors again.
Confirmation of the presence of glucose was obtained by dropping
in a mercuric chloride paper, while the solution was still quite
hot, after the complete development of the indigo reaction. Then
there was produced immediately a blackish green precipitate. No such
precipitation occurred when a drop of non-saccharine urine was under
examination by the indigo test; then the blue solution was merely
turned into a transparent green one.
This test, as Dr. Oliver pointed out, discovers (_a_) the normal sugar;
(_b_) the varying proportions of sugar which fill in the gap between
the normal amount and that which characterizes diabetes mellitus, as
in liver derangements and vaso-motor disturbances; (_c_) diabetic
proportions.
It possesses the following advantages over Fehling's test:
1. It will detect sugar in any proportion in the presence of albumen,
peptone, blood, pus, or bile, and as readily as in ordinary diabetic
urine.