_Why are some volatile oils obtained by expression?_

Because they are contained in distinct vesicles in the rind of fruits, as
in the lemon, orange, and bergamot.

_Why is the oil of poppy-seed perfectly wholesome?_

Because it is in no degree narcotic; nor has it any of the properties of
the poppy itself. This oil is consumed on the Continent in considerable
quantity, and employed extensively in adulterating olive oil. Its use was
at one time prohibited in France, by decrees issued in compliance with
popular clamour; but it is now openly sold, the government and people
having grown wiser.

_Why is the juice of the poppy called opium?_

Because of its derivation from the Persian _afioun_, and the Arabian
_aphium_. The botanical name of the poppy, _papaver_, is said to be
derived from its being commonly mixed with the pap, papa, given to
children in order to ease pain, and procure sleep.

_Why does opium produce sleep?_

Because it contains an alkaline substance called Morphia. The same drug
contains a peculiar acid called the Meconic; and a vegetable alkali named
Narcotine, to which unpleasant stimulating properties are attributed by
Majendie.

_Why is sugar so generally found in plants?_