, and
that as much attention should be paid to the paper as to the tub. A
most efficient way of treating paper, either for tub liners or print
wrappers is to place same in boiling water for a few minutes.

CHAPTER VIII.

BACTERIA AND CHEESE MAKING.

Butter, such as that of the sweet-cream type that is highly esteemed
in many parts of the world, may be made without the aid of bacteria,
but no important kind of cheese can be made under commercial
conditions without them.

=Types of cheese.= Cheese consists of the fat and the precipitated
casein of milk, together with a large amount of water and the salts
found in milk. The numerous types of cheese may be divided into two
groups, depending on the manner in which the curdling of the milk is
brought about. Sour-milk cheese is made from curd, formed as a
result of the acid fermentation of the milk. Thus, at the very first
stage in the making of this type, the importance of bacteria is
apparent.

The second type is that made from curd, which is precipitated by the
addition of rennet to the milk. This type may also be divided into
two groups, depending upon their texture; the hard cheese, and the
soft cheese. The ordinary cheddar, the common American type, is the
most important example of the hard cheese; Limburger, of the soft
cheese. Cheese are designated as hard or soft, depending upon the
amount of whey that is retained in them during the making process.
The moisture content has an important influence on the type and
amount of life that develops on and in the curd mass, and as will be
seen, the ripening and flavor of the cheese are dependent upon these
biological factors.

The two groups of hard and soft cheese have no sharply defined
limits, but merge into each other. The extreme types of the hard
cheese are so dry and firm that they can be cut only with
difficulty. Such cheese are used primarily as condiments to impart a
flavor to certain dishes, as macaroni, and for this purpose are
grated. The extreme type of soft cheese is a soft, pasty mass and
can be easily spread with a knife.

Hard cheese, because the ripening process goes on uniformly
throughout the entire mass of cheese, may be made of any size which
permits of commercial handling. They can also be kept for long
periods and preserve their good qualities. Soft cheese are made in
small sizes, since on account of their consistency, they could not
otherwise be handled, and also because of the manne