adherent and not crumbly when molded into shapes. Pure butter is
very light in color; nearly all that is sold is colored, in order to
meet the popular demand for "yellow" butter; annatto and other
vegetable and mineral substances are sometimes employed for this
purpose. These coloring matters are generally harmless but may be
detected by dissolving a portion of the butter in alcohol; the natural
color will dissolve, while foreign coloring will not. Butter should
consist of eighty-five per cent fat, with the remainder water,
casein, and salt. The most common methods of adulteration consist in
an excess of water and the addition of oleomargarine. If an excess of
water has been added it may be shown by melting the butter; the water
and fat will separate in two distinct layers. Oleomargarine has a
distinctive meaty smell, like that of cooked meat, and lacks the
characteristic odor of pure butter. If pure butter is melted in a
spoon, it will not sputter; if oleomargarine is present, it will.

The preservatives sometimes used, namely, boric and salicylic acids
and formaldehyde, can only be detected by chemical tests.

=Eggs.=--Two methods may be used to detect stale eggs. First: make a
solution of one part of table salt to ten parts of water and immerse
the suspected egg; if it sinks, it is perfectly fresh; if it remains
in the water below the surface, it is at least three days old, and if
it floats, it is five or more days old.

Second: hold the egg between a bright light and the eye. If it is
fresh, it will show a rosy tint throughout, without dark spots, as the
air chamber is small; if not fresh, it will look cloudy, with many
dark spots present.

=TEA AND COFFEE.=--These substances are extensively adulterated, but
the adulterants are almost without exception harmless.

=Tea.=--The commonest forms of adulteration of tea are as follows:
(_a_) Exhausted tea leaves which have already been used are dried and
added. Their presence may be detected by the weakness of the infusion,
made from a given quantity of the suspected tea, compared with a
similar infusion made from tea known to be pure. (_b_) Leaves from
other plants are sometimes dried and added; these are easily shown if
an infusion is made and when the leaves are thoroughly wet unrolling
and comparing them. (_c_) Green teas may be "faced" or colored with
Prussian blue, indigo, French chalk, or sulphate of lime; black teas
may be similarly treated with plumbago or