9. Lettuce is a well-known herb that is much used as a salad vegetable.
There are numerous varieties of lettuce, but these may be reduced to the
two kinds shown in Fig. 2, _leaf lettuce_ on the right and _head
lettuce_ on the left. Leaf lettuce, which is more often used for
garnishing than for any other purpose, has firm, crisp, green, upright
leaves; on the other hand, head lettuce has round leaves forming a
compact head, like cabbage. The outside leaves of head lettuce are
green, but the inside ones are usually bleached by the exclusion of
light, as are those of cabbage and endive. These inside leaves are more
tender than the others, and hence more to be desired as a salad
vegetable than the unbleached variety. In food value, lettuce compares
closely with other varieties of greens and is high in the same mineral
salts that they are. The bleached leaves do not contain so much iron as
the green ones. [Illustration: FIG. 2]
10. As has already been implied, lettuce finds its principal use in
garnishing salads. When used for this purpose, it should be eaten along
with the salad, for it is too valuable to be wasted. Since the coarse
outside leaves of a stalk or a head of lettuce do not look so well as
the tender bleached ones, they are often rejected, but this should not
be done, for use can also be made of them. For instance, such leaves may
be shredded into narrow strips and used as a foundation for salads that
will be just as attractive as those having a single lettuce leaf for a
garnish. When it is realized that the outside leaves are purchased at
the same price as the more delicate parts of the lettuce, it can readily
be understood why they also should be utilized as food. Most of the
garden varieties of lettuce, especially when they have grown very large,
are frequently cooked as greens. When used in this way, lettuce is
prepared, as are other greens, according to the directions given in Art.
3. This vegetable also makes an appetizing dish when it is prepared with
a sauce and served hot in the same way as dandelion.