The Evening critic., 1883-04-30
OLEOMARGARINE,
s'Ts u Possibie 10 Detec, A.,

TO the Editor of he Evening Critic.
In your Issue OF April 81, the above caption
appears heading an article relating to Profes.
sor o,i De smedts experience with my sulphnr.c
acid lest OF oleomargarine and butter Pro.
lessor De Smedt is represented as saying,
"Tests OF genuine and imitation butter had
neen maze and the different colors, crimson
anu purple been produced" BY this Pro.
lessor De smidt appears to moan that when
colored oleoinargnrine, as found In commerce,
Is treated With sulphuric acid, It will turn a
cIilnson color this being the fact In the case)
ana mat when pure butter is 30 treated 1t
turns purple color which, however, does
not describe the actual color obtained in my
own experiment go well as the term light red
This being Professor De Smedt's meaning,
his experience go far agrees substantially
,ay Win my own. He says, however, If correctly
reported, that "when pure and uncolored
oleomargarino was tested, 1t produced OK.
actly the same result as the test of pure but
Ter II the test OF pure butter produces pur.
pie, as professor Do Smedt Is reported to say,
OF light red, as my own experience shows,
the color Is certainly not Identical with that
obtained from the puro uncolored oleomarga.
ilne lat, whether II be that of the OK or that OF
the hog which is used. Both OF these fats re
charred by the action Of suiphurlc acid, pro-
aucing, In all cases, transparent amber
within twenty.four hours after treatment;
while pure butter, under the same conditions,
assumes first the reddish or purpiish tint al.
ready referred to- and within twenty.four
hours after treatment becomes white. There
Is then, according to Professor De. Smedts
own own statement. one result for the oleomarga-
rine r,i OF commerce and another result for pure
putter, so that these two substances may
obviously be distinguished from each
91her %hNI by my suiphuric acid test.
Ihere is also still another result for
each OF tho fats supposed to enter into the
composition OF oleomargarine and OF which
uncolored oleomargorine is composed, so
lhat aha pure butter is evidently distinguish
colored oleomargarine. Obviously, then,
w,e, we nave the means OF distinguishing pure
butter when uncolored from either colored or
uncolored oleomargarine. Professor De smedt
is reported as saying, as the result OF his OK.
periments, "that the coloring matter, and not
me w, animal fat In the compound, caused the
aiIerences In color In the results OF the test"
Iv,,,s whis conclusion Is wholly inconsistent
may, may easily satisfy himself, that the
sume under the acid test the perfectly dis.
tinctive colors mentioned above Had Pro.
lessor Dc smedt observed the three prominent
ana butter pass under the acid test
this test is not vitlated even though both sub.
stances, under the effect of a vegetable color.
Ing matter, should turn crimson at the second
stage In the experiment, as in twenty.four
hours the oleomargarine VIII change to very
DARK brown, while the butter Will become
white or the color Of clear tallow.
Professor De Smedt is aware that in all my
experiments in the late trial used my double
tests in every instance. That Is, 1 subjected
the suspected butter first to the action OF DO.
larized light, under the microscope, aud sec.
ondly to tho action OF sulphuric acid; and
numerous as were the samples tested, I did
not make one failure. Genuine butter, even
though arti1cially colored, will present under
polarized light one even color over the whole
Held OF view, while oleomargarine, whether
colored or colorless, Will exhibit all the colors
OF the rainbow. SO conclusive are my micro.
scopic tests with polarized light that am able
by Its means to detect the adulteration of but.
ter with crystalized fat II even the minutest
particle OF the latter be present: and my two
sets OF tests-microscopic and chemic-nu.
tually confirm each other Yours respectfully,
THOMAS TAyToR N n