has
begun to decompose and while the decomposition may not have advanced
sufficiently far to be discernible from the flavor or odor, it is
there, and if the resistance of the individual eating this food is not
great, serious danger may result. Poisoning develops in some
individuals upon the eating of shellfish, strawberries, oranges,
pimentos, and various other foods,--another evidence of personal
idiosyncrasy against certain articles of diet. There is no way to
overcome these idiosyncrasies; the only thing to do is to warn the
individuals so affected to let the offending foods alone.

ADULTERATION OF FOOD

The adulteration of food, which formerly was practised by unscrupulous
dealers to cover up inferior articles, or by manufacturers to prevent
or arrest decomposition in canned goods, is regulated by law. The
passage of the National Pure Food and Drug Act gave the Government
authority to regulate the preservatives and coloring matter used in
canned and bottled goods, forcing the manufacturers to state on the
label the exact contents of each bottle or can. There are likewise
stringent laws governing the adulteration of milk, butter, and other
articles of food.

~Tests for Adulterants.~--Boric acid, borax, and formaldehyde are the
preservatives more often found in milk. These chemicals are introduced
to arrest the natural souring and decomposition which takes place
after milk reaches a certain age. Occasionally salicylic acid and
sodium carbonate are used. Formaldehyde may be detected by placing
about 20 c.c. of milk in a small glass vessel or tube. Dilute with an
equal amount of pure water, add commercial sulphuric acid, allowing it
to flow gently down the inside of the tube. A purple ring will appear
at the zone of contact if formaldehyde is present. "Boric acid and
borax may be detected by adding a drop or two of hydrochloric acid to
a few drops of milk in a white dish and then several drops of a
saturated alcoholic solution of _turmeric_. The dish is then heated
gently for a few minutes, and, if boric acid or borax is present, a
pink or dark red color will appear. A dark blue-green should appear
when the dish is cooled and a drop of ammonia added."[28]

~Canned goods~ must be carefully examined before being used. The
domestic canned goods are rarely adulterated, but imperfect
sterilization and defective cans may bring about a condition of
fermentation and gas formation due to bacterial action. Cans should
ha