rk of reproduction goes on.

In the first stages molds are white or light gray and hardly noticeable;
but when spores develop the growth gradually becomes colored. In fact,
the conditions of advanced growth might be likened to those of a flower
garden. The threads--mycelium--might be likened to the roots of plants
and the spores to the flower and seeds.

Mold spores are very light and are blown about by the wind. They are a
little heavier than air, and drop on shelves, tables, and floor, and are
easily set in motion again by the movement of a brush, duster, etc. If
one of these spores drops on a jar of preserves or a tumbler of jelly,
it will germinate if there be warmth and moisture enough in the
storeroom. Molds do not ordinarily cause fermentation of canned foods,
although they are the common cause of the decay of raw fruits. They are
not as injurious to canned goods as are bacteria and yeasts. They do not
penetrate deeply into preserves or jellies, or into liquids or
semiliquids, but if given time they will, at ordinary room temperature,
work all through suitable solid substances which contain moisture.
Nearly every housekeeper has seen this in the molding of a loaf of bread
or cake.

In the work of canning, preserving, and jelly making it is important
that the food shall be protected from the growth of molds as well as the
growth of yeasts and bacteria.

To kill mold spores food must be exposed to a temperature of from 150
deg. F. to 212 deg. F. After this it should be kept in a cool, dry place
and covered carefully that no floating spore can find lodgment on its
surface.

STERILIZATION.

To sterilize a substance or thing is to destroy all life and sources of
life in and about it. In following the brief outline of the structure
and work of bacteria, yeasts, and molds, it has been seen that damage to
foods comes through the growth of these organisms on or in the food;
also that if such organisms are exposed to a temperature of 212 deg. F.,
life will be destroyed, but that spores and a few resisting bacteria are
not destroyed at a temperature of 212 deg. F., unless exposed to it for
two or more hours.

Bacteria and yeasts, which are intimately mixed with food, are not as
easily destroyed as are those on smooth surfaces, such as the utensils
and jars employed in the preparation of the food.

Since air and water, as well as the foods, contain bacteria and yeasts,
and may contain mold spores, all utensils us