_Foods._--The body uses food to build and repair its tissues, to provide
heat and energy, and to regulate the body processes. Foods differ from
one another in their composition and in their ability to assist the body
in the performance of its varied functions. These differences have led
to the classification of foods into five groups, which are spoken of as
the five food-stuffs or food principles.
_Cooking._--While some foods can be used as they occur in nature, most
of them are made more acceptable by the application of heat. Heat
softens the structure of vegetables and fruits, makes tender the tissues
of meat, prepares starch for digestion, develops the flavour in many
foods, and destroys the parasites and germs that may be present. The
five food-stuffs are differently affected by heat--some require slow
cooking, others require intense heat. Hence, it is necessary to study
cooking, in order that each food may be properly prepared.
_The stove._--A knowledge of the construction of the stove and the
methods whereby heat is obtained is imperative if one is to be a
successful cook. For all stoves three things are necessary--fuel, a
supply of oxygen, and a certain degree of heat, known as the kindling
point, whereby the fire is started. The supply of oxygen is regulated by
dampers and checks so arranged as to admit or cut off the draught of
air.
The creative dampers are doors or slides that come below the fire box.
When open, they admit the entrance of air, increase the draught, and
facilitate combustion.
The oven damper is a flat plate which closes the opening into the
chimney flue, to decrease the drawing of the draught. When the oven
damper is closed, the heat from the fire remains in the stove and passes
around the oven.
Checks are doors or slides higher than the fire-box, which, when open,
allow the cold air to pass over the fire, retarding combustion.
A stove is also provided with means for disposing of the ashes, soot,
and the gases formed. All parts of the stove are so arranged that they
may be kept clean.
(See Twenty Lessons in the Care of the Home. Lesson I)