56. Fresh Vegetables.—The use of fresh green vegetables is necessary to health. Persons deprived of them for any great length of time, as sailors sometimes are at sea, become subject to a very serious and fatal disease termed scurvy. The number of fresh vegetables used as food is very great, but the most valuable are potatoes, cabbages, turnips, carrots, parsnips, and onions. Peas and beans are also largely used in a green state.