aracter for that of
any other oil. The finest virgin oil is pale green in color, the
cheaper grades are light yellow.

The adulterants consist of cotton-seed, corn, mustard, and peanut
oils.

When pure olive oil is shaken in a glass or porcelain dish with an
equal quantity of concentrated nitric or sulphuric acid[7] it turns
from a pale to a dark green color in a few minutes; if under this
treatment a reddish to an orange or brown color is produced the
presence of a foreign vegetable oil is to be suspected.

=FLAVORING EXTRACTS--Vanilla.=--This may be wholly or in part the
extract of the Tonka bean or may be made from a chemical substance
known as vanillin. The best practical working tests as to its purity
are the price, taste, and odor. The distinctive odor and taste of
vanilla are characteristic and cannot be mistaken.[8]

=Lemon.=--This extract is often made from tartaric or citric acid.
They may be tested for as follows: to a portion of the extract in a
test tube add an equal volume of water to precipitate the oil; filter,
and add one or two drops of the filtrate to a test tube full of cold,
clear limewater; if tartaric acid is present a precipitate will fall
to the bottom of the tube. Filter off this precipitate (if present)
and heat the contents of the tube; if citric acid is present it will
precipitate in the hot limewater.

FOOTNOTE.--Dr. Baker wishes to acknowledge her indebtedness to the
following authorities and the volumes mentioned for many helpful
suggestions. Pearman and Moore, "Aids to the Analysis of Foods and
Drugs"; Albert E. Leach, "Food Inspection and Analysis"; Francis
Vacher, "Food Inspector's Hand Book."

FOOTNOTES:

[4] The presence of aniline dyes may be detected by mixing a portion
of the suspected sample with enough water to make a thin paste. Wet a
piece of white wool cloth or yarn thoroughly with water and place it
with the paste in an agate saucepan. Boil for ten minutes, stirring
frequently. If a dye has been used the wool will be brightly colored;
a brownish or pinkish color indicates the natural coloring matter of
the fruit or vegetable.--EDITOR.

[5] A little vinegar added to heated cream or milk produces in the
curd a distinct orange color if an aniline dye has been used to make
the cream look "rich." The curd will be brown if annatto or caromel
has been used. If pure, the curd will be white.--EDITOR.

[6] This acid must be used with great care; n