Every vegetable, spice, and sweet herb, curry-powders, catchups, sauces, dried or fresh lemon-peel, can be used; and the simple stock, by the addition of these various ingredients, becomes the myriad number of soups to be found in the pages of great cooking manuals like Gouffee's or Francatelli's.
_Brown soups_ are made by frying the meat or game used in them till thoroughly brown on all sides, and using dark spices or sauces in their seasoning.
_White soups_ are made with light meats, and often with the addition of milk or cream.
_Purees_ are merely thick soups strained carefully before serving, and made usually of some vegetable which thickens in boiling, as beans, pease, &c, though there are several forms of fish _purees_ in which the foundation is thickened milk, to which the fish is added, and the whole then rubbed through a common sieve, if a regular puree-sieve is not to be had.
Browned flour is often used for coloring, but does not thicken a soup, as, in browning it, the starchy portion has been destroyed; and it will not therefore mix, but settles at the bottom.

Burned sugar or caramel makes a better coloring, and also adds flavor.

With clear soups grated cheese is often served, either Parmesan or any rich cheese being used.

Onions give a better flavor if they are fried in a little butter or dripping before using, and many professional cooks fry all soup vegetables lightly.
Cabbage and potatoes should be parboiled in a separate water before adding to a soup.

In using wine or catchup, add only at the last moment, as boiling dissipates the flavor.