This section is from the book "Economical Cookery", by Marion Harris Neil. Also available from Amazon: Economical Cookery (1918).
"It provoketh a fine appetite if sauce your meat be by."
It is an art to make a really good sauce - an art not sufficiently cultivated by the majority of cooks, yet one worthy of cultivation, for by means of a good sauce many ordinary dishes can often be redeemed from the commonplace.
A smooth, well-flavored sauce is not so very difficult to manufacture if a little care and thought are bestowed upon it. It need not be rich and elaborate, but it must be thoroughly blended and cooked; one seasoning must not unduly predominate over another, and it must be suitable for the dish with which it is to be served.
Sauces have several uses: They may supply some food deficiency in the dish; they may help to counteract the extreme richness of a dish; and they may simply act as an appetizer to an otherwise somewhat insipid dish. Sauces are economical, for they make whatever they are served with go farther. A little rather expensive fish, served in plenty of comparatively inexpensive sauce, will go a long way, and at the same time taste a great deal better for the addition. The same is true of meat, vegetables, and puddings. Left-overs can be heated up in fresh sauce, and will become hot and tempting dishes. The aims in sauce making are: to produce a well-flavored sauce, to make it of the right consistency, and to keep a good color.
Sauces are qualified as follows:
1. Sauces thickened with butter and flour cooked together to form a roux, either white or brown. Plain white and brown sauces, known as foundation sauces, and all the variations of the above obtained by the addition of extra, distinctive seasonings, such as parsley, onion, capers, eggs, etc.
2. Sauces thickened with eggs, either cooked or uncooked.
3. Sauces thickened with a little blended flour or cornstarch, after the flavor of various ingredients has been extracted by long simmering.
4. Vinegar combined with oil, eggs, or cream.
5. Miscellaneous sauces.