Why are some oils called vegetable butters?

Because they become solid at the ordinary temperatures.  Such are cocoa-nut oil, palm oil, and nutmeg oil.

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?

Because it is not only the seasoning of most eatable fruits, but abounds in various roots, as the carrot, beet, parsnip, and in many plants of the grass, or cane kind, besides the famous sugar cane.

Sir James Smith observes that “there is great reason to suppose sugar not so properly an original secretion, as the result of a chemical change in secretions already formed, either of an acid or mucilaginous nature, or possibly a mixture of both.  In ripening fruits, this change is most striking, and takes place very speedily, seeming to be greatly promoted by heat and light.  By the action of frost, as Dr. Darwin observes, a different change is wrought in the mucilage of the vegetable body, and it becomes starch.”

M. Berard considers gum and lignin as the principles in unripe fruits which chiefly tend to the formation of sugar during their ripening, and he has given several analyses of fruits in illustration of these views.  Mr. Brande also considers the elements of water as probably concerned in the change.

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THE NATURALIST.

THE SUGAR CANE.

At the island of Tahiti (Otaheite) South Pacific Ocean, there are several varieties of the sugar cane, differing, however, in their qualities.  The number of varieties are eight, and are as follow:—­

1.  Rutu—­of good quality.

2.  Avae—­of indifferent quality.