The Evening critic., 1883-05-04
oLEoMARGARINE AND BUTTER.
Professor De Smedt Again Take
Issue with Professor Taylor OF
the SuIphuric Acid Test.

The discussion of the tests calculated TO
discriminate between genuine butter and
the spurious limitations of the article by
the eminent scientists, Professors Taylor
and De Smedt, as presented in the columns
of THE CRITIC, has attracted general inter
est among the dealers in and purchasers of
butter.
reporter called upon Professor De
Smedt this morning and found him SUR
rounded by the bottles, apparatus and
chemicals of his laboratory in his room at
Police Headquarters.
The reporter asked the Professor whether
he had read the communication of Professor
Taylor in defense of the sulphuric acid
test and whether he had any additional
light to throw ON the subject
Mr.. De Smedt replied: II read the state
ment of Professor Taylor in defense of the
sulphuric acid test Of butter and oleomar-
garine with care, but regret to say that it
did not convince me and cannot change
my opinion. / have made further expert
ments, and the more complete and careful
my tests, the more firmly 1 am convinced
of my former statements of the inconclu-
siveness of Professor Taylor's tests. 1t is
q well-known fact that butter and the imi-
tation thereof are fats containing many
impurities. They contain water, chloride
of sodium, very often nitrate of potash,
and col0ring matter. These impurities
exist in those fats in varied quantities, aud
have all different effect on the coloration
obtained with sulphuric acid, so that sui
phuric acid in contact with these fats will
produce varied colors in accordance with
the existence, absence and quantities Of the
above-named impurities in butter or its
limitations. In my first conversation with
You stated that the coloring matter inter
feres with the sulphuric acid test, and
that with colored fats they test
all alike, or nearly so. So
it is with the presence of certain guam
tity Of nitrate Of potash, which obliterates
the sulphuric acid test. 1t becomes thus
evident that the application of sulphuric
soiled with different impurities is too crude
a method to be employed by experts and
chemists"
Have you made further tests with the
acid ?" queried the reporter.
Il have made number of additional
tests" continued the Professor, "with
chemically pure butter and fats, uncolored.
Among the results of these tests found
the following to be the case: Chemically
pure butter or lard produce with the acid
almost identical results-frst clean yell
low, then orange then red feshy tint,
then the purple and brownish, and
finally bleaching to dirty white.
Tallow produces clean yellow, then
orange, then red feshy color, which is
not always clearly visible; then purple,
blush, brownish and finally the. dirty
white. Butter mixed with lard or tallow
in equal parts produces the same colors as
unmixed butter. We might conclude
this to be n test for fats from
the OK, when not mixed with
butter or lard; but when mixed, the
test is entirely obliberated. All these fats,
when mixed with coloring matter and
tested with sulphuric acid, retain the dark
color for length of time in the ratio OF
the quantity of coloring matter which they
contain. As to the microscopic test, which
continues to be the best test we have for
| the examination of butter, it is still de.
fective in its results. When butter has been
melted or partially melted, which may
happen In warm room or by the heat OF
the sun, and under such circumstances the
| microscope will show the crystalizaton OF
the margarine, the microscopic may
classify the butter as oleomargarne OF
mixed with lard. OF course we have
several other tests more or less conclusive
but nothing positive, and the most reliable
| examination, in my opinion, is still by the
microscope, polarized light or otherwise"
Pleasant Musical Entertainnient.
| number of mutual friends had an
| agreeable social reunion on Wednesday